MMI COMPANIES INC
SC 14D1, 1997-11-06
SURETY INSURANCE
Previous: PUTNAM INVESTMENTS INC, SC 13G/A, 1997-11-06
Next: GLASGAL COMMUNICATIONS INC, 10-Q/A, 1997-11-06



<PAGE>
                                           
                          SECURITIES AND EXCHANGE COMMISSION
                                Washington, D.C. 20549
                                           
                                    SCHEDULE 14D-1
                      TENDER OFFER STATEMENT PURSUANT TO SECTION
                   14(d)(1) OF THE SECURITIES EXCHANGE ACT OF 1934
                                           
                                Unionamerica Holdings plc
          -----------------------------------------------------------------
                               (Name of Subject Company)
                                           
                                  MMI Companies, Inc.
            -------------------------------------------------------------
                                       (Bidder)
                                           
                             American Depositary Shares, 
                        each representing an ordinary share, 
                          nominal value $0.0448 per share
      -------------------------------------------------------------------------
                            (Title of Class of Securities)
                                           
                                       909048100
                       ---------------------------------------
                         (CUSIP Number of Class of Securities)
                                           
                                           
                               Wayne A. Sinclair, Esq.
                                 MMI Companies, Inc.
          540 Lake Cook Road, Deerfield, Illinois 60015-5290 (847) 940-7550
        ----------------------------------------------------------------------
             (Name, Address and Telephone Number of Person Authorized to
               Receive Notices and Communications on Behalf of Bidder)
                                           
                                   with a copy to:
                                           
                                Jerald P. Esrick, Esq.
                           Wildman, Harrold, Allen & Dixon
                                225 West Wacker Drive
                                      Suite 3000
                               Chicago, Illinois  60606
                                    (312) 201-2508
                                           

<PAGE>

                              CALCULATION OF FILING FEE

             --------------------------------------------------------
              Transaction Value*              Amount of Filing Fee**
               $  191,893,233                      $  38,379      
             --------------------------------------------------------

* For purposes of calculating the filing fee only.  This calculation assumes
7,685,336 shares of common stock, par value $0.10 per share, of MMI Companies,
Inc., will be issued in exchange for all outstanding American Depositary Shares
of Unionamerica Holdings plc, each  representing an ordinary share of
Unionamerica which are unconditionally issued or allotted upon the exercise of
options granted under existing Unionamerica share option schemes.  Pursuant to
Exchange Act Rules 0-11(d) and 0-11(a)(4) the filing fee was computed on the
average of the high and low prices of MMI Companies, Inc.'s common stock on
October 31, 1997 in the Consolidated Reporting System.
** 1/50 of one percent of the Transaction Value.
                                           
                                           
    /x/ Check box if any part of the fee is offset as provided by Exchange Act
    Rule 0-11(a)(2) and identify the filing with which the offsetting fee was
    previously paid.  Identify the previous filing by registration statement
    number, or the Form or Schedule and the date of its filing.

               Amount previously paid:       $71,387

               Form or Registration 
               Statement No.:                333-32027

               Filing Party:                 MMI COMPANIES, INC.

               Date Filed:                   JULY 25, 1997

                                        - 2 -
<PAGE>

1)  Names of Reporting Persons 
    I.R.S. Identification Nos. of Above Persons

           MMI Companies, Inc., a Delaware corporation
           36-3263253

- --------------------------------------------------------------------------------

2)  Check the Appropriate Box if a Member of a Group     (a)     [  ]
                                                         (b)     [  ]

- --------------------------------------------------------------------------------

3)  SEC Use Only 

- --------------------------------------------------------------------------------

4)  Sources of Funds

          OO

- --------------------------------------------------------------------------------

5)  Check if Disclosure of Legal Proceedings is Required Pursuant to 
Items 2(e) or 2(f) ___ 

- --------------------------------------------------------------------------------

6)  Citizenship or Place of Organization

         Delaware



                                        - 3 -
<PAGE>

- --------------------------------------------------------------------------------

7)  Aggregate Amount Beneficially Owned by Each Reporting Person

         0

- --------------------------------------------------------------------------------

8)  Check if the Aggregate Amount in Row (7) Excludes Certain 
Shares _________

- --------------------------------------------------------------------------------

9)  Percent of Class Represented by Amount in Row (7)

         0

- --------------------------------------------------------------------------------

10) Type of Reporting Person

         CO

- --------------------------------------------------------------------------------



                                        - 4 -
<PAGE>

    This Schedule 14D-1 Tender Offer Statement (this "Statement") relates to
the offer by MMI Companies, Inc., a Delaware corporation ("Bidder" or "MMI"), to
acquire all outstanding American Depositary Shares, each representing an
ordinary share, nominal value $0.0448 (a "Unionamerica ADS"), of Unionamerica
Holdings plc, a corporation registered in England and Wales under the Companies
Act 1985 of Great Britain, as amended, registered number 2822469
("Unionamerica"), in exchange for 0.836 shares of common stock, par value $0.10
per share, of MMI (the "MMI Common Stock"), upon the terms and subject to the
conditions set forth in the Offer to Exchange/Prospectus, dated November 5, 1997
(the "Prospectus"), and in the related Letter of Transmittal (which, as amended
from time to time, together constitute the "Offer").   Copies of the Prospectus
and the Letter of Transmittal are annexed hereto as Exhibits (a)(1) and (a)(2),
respectively.

ITEM 1.        SECURITY AND SUBJECT COMPANY

    (a)  The subject company is Unionamerica Holdings plc, a corporation 
registered in England and Wales under the Companies Act 1985 of Great 
Britain, as amended, registered number 2822469.  The address of its principal 
executive office is London Underwriting Centre, 3 Minster Court, Mincing 
Lane, London EC3R 7DD, England.

    (b)  The information set forth on the Cover Page of the Prospectus is 
incorporated herein by reference.

    (c)  The information set forth in "Prospectus Summary - Market Price of 
MMI Common Stock and Unionamerica ADS", and Appendix D of the Prospectus 
- -"Certain Market, Dividend and Exchange Rate Information" is incorporated 
herein by reference.

         The following is the high and low sales price for Unionamerica ADSs on
the New York Stock Exchange for each quarterly period during the last two years:

                                                       High      Low
                                                       ----      ---

               Fourth Quarter, 1995                   17.375    16.625
               First Quarter, 1996                    17.75     16.1250
               Second Quarter, 1996                   17.625    15.1250
               Third Quarter, 1996                    19.50     15.1250
               Fourth Quarter, 1996                   20.6250   16.75
               First Quarter, 1997                    19.50     15.25
               Second Quarter, 1997                   20.6875   16.00
               Third Quarter, 1997                    22.5625   19.625



                                        - 5 -
<PAGE>

ITEM 2.        IDENTITY AND BACKGROUND.

    (a-d, g)  MMI Companies, Inc., a Delaware corporation, is an international
healthcare risk management company.  Through its operating subsidiaries, MMI
provides professional liability insurance and reinsurance, education and
information management products, clinical and financial risk management
services, managed care design and infra-structure development, healthcare
restructuring products and strategic management, and employee relations and
human resource consulting services.  The address of its principal executive
office is 540 Lake Cook Road, Deerfield, Illinois 60015-5290.

    The following table sets forth the name, business or residence address,
principal occupation or employment at the present time and during the last five
years, and the name of any corporation or other organization in which such
employment is conducted or was conducted of each executive officer or director
of MMI.  Except as otherwise indicated, all of the persons listed below are
citizens of the United States of America.  Each occupation set forth opposite a
person's name, unless otherwise indicated, refers to employment with MMI. 
Unless otherwise indicated, the principal business address of each director or
executive officer is MMI Companies, Inc., 540 Lake Cook Road, Deerfield,
Illinois 60015-5290.

<TABLE>
<CAPTION>

                 NAME, CITIZENSHIP                         PRESENT OCCUPATION                     MATERIAL POSITIONS HELD
                        AND                                       OR                                     DURING THE
             CURRENT BUSINESS ADDRESS                         EMPLOYMENT                              PAST FIVE YEARS            
   ------------------------------------------   --------------------------------------   ----------------------------------------
<S>                                             <C>                                      <C>
 Richard R. Barr.............................   Executive Vice President -               President - Presbyterian Healthcare
 Rust Tractor Co.                               Rust Transfer Co. since 1995;            Services from 1969 to 1995
 4000 Osuna Road, NE                            Director - MMI since 1986                P.O. Box 26666
 Albuquerque, New Mexico  87125                 President Emeritus - Presbyterian        Albuquerque, New Mexico  87125
                                                Healthcare Services from 1995 to      
                                                Present                               
                                                5901 Harper Drive, NE                 
                                                Albuquerque, New Mexico 87109         
                                                                                      
 B. Frederick Becker.........................   Chairman and Chief Executive Officer -   President and Chief Executive Officer -
                                                MMI since 1994;                          MMI from 1985 to 1994
                                                Director - MMI since 1985;            
                                                                                      
 George B. Caldwell..........................   President Emeritus - Lutheran General    President - Lutheran General
 The Collier Company                            HealthSystem since 1990;                 HealthSystem from 1984 to 1990
 205 W. Touhy Avenue                            Chairman - Collier Company since 1990;   1175 Dempster
 Park Ridge, Illinois  60068                    Director - MMI since 1983                Park Ridge, Illinois  60068
                                                                                      
 K. James Ehlen, M.D. .......................   President - Allina Health System since   Chairman and Chief Executive Officer -
 Allina Health System                           1994;                                    Medica Health Plan from 1991 to 1994
 5601 Smetana Drive                             Director - MMI since 1997                5601 Smetana Drive
 Minneapolis, Minnesota 55436                                                            Minneapolis, Minnesota 55436
                                                                                      


                                       -6-
<PAGE>

 F. Laird Facey, M.D. .......................   Surgeon - Facey, Shorr, Smith, M.D.'s    Surgeon - Facey, Shorr, LoPresti from
 Facey, Shorr, Smith, M.D.'s                    since 1992;                              1990 to 1992
 323 N. Prairie Avenue                          Director - MMI since 1983                323 N. Prairie Avenue
 Suite 208                                                                               Suite 208
 Inglewood, California 90301                                                             Inglewood, California 90301
                                                                                      
 Anna Marie Hajek............................   Executive Vice President - MMI since     President - MMI Risk Management
                                                1995;                                    Resources, Inc. from 1992 to 1997
                                                President - MMI Healthcare Services   
                                                Group since 1995                      
                                                                                      
 William M. Kelley...........................   Chairman and CEO - Hill-Rom since        President and Chief Executive Officer
 Hill-Rom                                       1995;                                    Hill-Rom from 1992 to 1995
 1069 State Route 46E                           Director - MMI since 1993             
 Batesville, Indiana 47006                                                            
                                                                                      
 Andrew D. Kennedy...........................   Partner - Beachroft Stanleys from     
 [United Kingdom citizen]                       since 1970                            
 Beachcroft Stanleys                            Director - MMI since 1996             
 20 Farnival Street                                                                   
 London EC4A 1BN England                                                              
                                                                                      
 Timothy R. McCormick........................   President - Park Ridge Health System  
 Park Ridge Health System                       since 1973;                           
 1555 Long Pond Road                            Director - MMI since 1986             
 Rochester, New York 14626                                                            
                                                                                      
 Gerald L. McManis...........................   President - McManis Associates, Inc. 
 McManis Associates, Inc.                       since 1964;                  
 1900 K Street, NW                              Director - MMI since 1994             
 Washington, DC  20006                                                                
                                                                                      
 Paul M. Orzech..............................   Executive Vice President and Chief       Vice President-Finance - Security Life
                                                Financial Officer - MMI since 1993       of Denver Insurance Company from 1990 to
                                                                                         1993
                                                                                         1290 Broadway
                                                                                         Denver, Colorado
                                                                                      
 Scott S. Parker.............................   President and Chief Executive Officer 
 Intermountain Health Care, Inc.                - Intermountain Health Care, Inc.     
 Beneficial Life Tower, 22nd Floor              since 1975;                           
 36 S. State Street                             Director - MMI since 1986             
 Salt Lake City, Utah 84111                                                           
                                                                                      
 Edward C. Peddie............................   President and Chief Executive Officer    President and Chief Executive Officer -
 AvMed-SantaFe                                  - AvMed-Santa Fe since 1996;             AvMed HealthPlan Santa Fe from 1978 to
 8930 Northwest 39th Avenue                     Director - MMI since 1990                1996
 Gainesville, Florida 32606                                                              8930 Northwest 39th Avenue
                                                                                         Gainesville, Florida 32606
                                                                                      


                                       -7-
<PAGE>

 Joseph D. Sargent...........................   Chairman and Chief Financial Officer -   Chairman -- Conning & Company from 1991
 Connecticut Surety Company                     Connecticut Surety Company since 1993;   to 1993;
 Cityplace II, 185 Asylum                       Director - MMI since 1985                Vice Chairman - Conning & Company from
 Hartford, Connecticut  06103-4105                                                       1993 to 1995 
                                                                                         Cityplace II, 185 Asylum
                                                                                         Hartford, Connecticut  06103-4105
                                                                                      
 Steve A. Schleisman.........................   Executive Vice President - MMI and       President - American International
                                                President - MMI Insurance Group since    Underwriters-North America, Inc. from
                                                1995                                     1972 to 1995
                                                                                         80 Pine Street
                                                                                         New York, New York 10005

 Wayne A. Sinclair...........................   Senior Vice President, Secretary and
                                                General Counsel - MMI since 1987
</TABLE>



    (e-f)   During the last 5 years, neither MMI nor, to the best knowledge of
MMI, the persons listed above, has been (i) convicted in a criminal proceeding
(excluding traffic violations or similar misdemeanors), or (ii) a party to a
civil proceeding of a judicial or administrative body of competent jurisdiction
and as a result of such proceeding was or is subject to a judgment, decree or
final order enjoining future violations of, or prohibiting activities subject
to, federal or state securities laws or finding any violation of such laws.

ITEM 3.     PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH THE SUBJECT
COMPANY.

    (a-b)   The information set forth in "Prospectus Summary - Summary of the
Offer and Proposed Acquisition", "THE OFFER - Background of the Proposed
Acquisition", and "THE OFFER - Material Contracts between MMI and Unionamerica"
in the Prospectus is incorporated herein by reference.

ITEM 4.     SOURCE AND AMOUNT OF FUNDS OF OTHER CONSIDERATION.

    (a)     The information set forth on the Cover Page of the Prospectus and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition" and "THE
OFFER - Changes in the Rights of Unionamerica Securityholders - Dividends" in
the Prospectus is incorporated herein by reference.  

    (b-c)   No part of such funds or other consideration are or are expected to
be, directly or indirectly, borrowed for the purpose of the Offer. 

ITEM 5.     PURPOSE OF THE TENDER OFFER AND PLANS OR PROPOSALS OF THE BIDDER.

    The information set forth in "MMI's Reasons for the Proposed Acquisition
and Recommendation of the MMI Board" in the Prospectus is incorporated by
reference herein.


                                        - 8 -
<PAGE>

    (a)     MMI does not currently contemplate any extraordinary corporate
transaction, such as a merger, reorganization or liquidation, concerning
Unionamerica or any of its subsidiaries.

    (b)     MMI does not currently contemplate any sale or transfer of a
material amount of assets of Unionamerica or any of its subsidiaries.

    (c)     MMI currently contemplates replacing a majority of the members of
the Board of Directors of Unionamerica after the consummation of the Proposed
Acquisition (as defined in the Prospectus).

    (d)     The information set forth on the Cover Page of the Prospectus, and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition", "THE
OFFER - Background of the Proposed Acquisition", "THE OFFER - Terms of the Offer
and Proposed Acquisition", "THE OFFER - Proposed Refinancing of Bank Debt", "THE
OFFER - Description of MMI Capital Stock", "THE OFFER - Description of
Unionamerica Capital Stock", "THE OFFER - Changes in the Rights of Unionamerica
Securityholders", and "Appendix D - Certain Market, Dividend and Exchange Rate
Information" in the Prospectus is incorporated by reference herein.

    (e)     MMI does not currently contemplate any material change in
Unionamerica's corporate structure or business, other than the change in
ownership contemplated by the Offer.

    (f)     The information set forth on the Cover Page of the Prospectus, and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition", "THE
OFFER - Terms of the Offer and Proposed Acquisition", "THE OFFER - MMI's Reasons
for the Proposed Acquisition and Recommendation of the MMI Board", "THE OFFER -
Unionamerica's Reasons for the Proposed Acquisition and Recommendation of the
Unionamerica Board", "THE OFFER - Proposed Refinancing of Bank Debt", "THE OFFER
- - Description of MMI Capital Stock", "THE OFFER - Description of Unionamerica
Capital Stock", and "THE OFFER - Changes in the Rights of Unionamerica
Securityholders" in the Prospectus is incorporated by reference herein.

    (g)     The information set forth on the Cover Page of the Prospectus, and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition", "THE
OFFER - Terms of the Offer and Proposed Acquisition", "THE OFFER - MMI's Reasons
for the Proposed Acquisition and Recommendation of the MMI Board", "THE OFFER -
Unionamerica's Reasons for the Proposed Acquisition and Recommendation of the
Unionamerica Board", "THE OFFER - Proposed Refinancing of Bank Debt", "THE OFFER
- - Description of MMI Capital Stock", "THE OFFER - Description of Unionamerica
Capital Stock", and "THE OFFER - Changes in the Rights of Unionamerica
Securityholders" in the Prospectus is incorporated by reference herein.


                                        - 9 -
<PAGE>

ITEM 6.     INTEREST IN SECURITIES OF THE SUBJECT COMPANY.

    (a)     None of the persons named in Item 2 of this Statement, or any
associate and/or majority-owned subsidiaries of such persons, directly or
indirectly beneficially own any securities of Unionamerica.

    (b)     There have been no transactions in Unionamerica ADSs effected
during the past 60 days by the persons named in response to paragraph (a) of
this Item 6, or by any executive officer, director or subsidiary of any such
person.

ITEM 7.     CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH
RESPECT TO THE SUBJECT COMPANY'S SECURITIES.

    The information set forth on the Cover Page of the Prospectus, and in
"Prospectus Summary - Summary of the Offer and Proposed Acquisition", and "THE
OFFER - Terms of the Offer and Proposed Acquisition", in the Prospectus is
incorporated by reference herein.  

    The Undertakings described therein have been executed by the following
Selling Stockholders: International Insurance Investors, L.P., Centre
Reinsurance Limited, Trustees of the Estate of B.P. Bishop, J. P. Morgan Capital
Corp., Carlisle Ventures, Inc., III (Bermuda) Limited, IIA 401(k)/Pension Plan
FBO Craig Schwarberg, Robert A. Spass, Paul H. Warren, Beach Haven Investors,
Inc., IIA 401(k)/Pension Plan FBO Paul Warren, IIA 401(k)/Pension Plan FBO Brad
Cooper,  Robert A. Spass, Paul H. Warren, Bradley Cooper, Craig Schwarberg, IIA
401(k)/Pension Plan FBO Craig Schwarberg, UA Partners, L.P., UA Partners II,
L.P., Acadia Partners, L.P., Alisdair G. Bishop, Peter J. Cooper, Hugh C. Evans,
Howard G. Eyre, Hugh B. Jago, Roland J. James, Andrew M. Marks, Timothy P. Open,
Ian G. Sinclair, Trevor R. Smith, Stuart C. Willoughby and Anthony B. Withersby.

    Affiliates Agreements described therein have been executed by the following
persons:  UA Partners, L.P., Peter J. Cooper, Ian G. Sinclair, Robert A. Spass,
Steven B. Gruber, Paul H. Warren, Hugh B. Jago, Timothy P. Open, Andrew E.
Marks, and Alisdair G. Bishop. 

    The Acquisition Agreement described therein has been executed by MMI and
Unionamerica.

ITEM 8.     PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED.

    MMI has retained ChaseMellon Shareholder Services L.L.C. to act as the
Information Agent in connection with the Offer.  The Information Agent will
receive reasonable and customary compensation for its services and be reimbursed
for certain reasonable out-of-pocket expenses.  MMI has also agreed to indemnify
the Information Agent against certain liabilities and expenses in connection
with the Offer.


                                        - 10 -
<PAGE>

    MMI will not pay any fees or commissions to any broker or dealer or any
other person for soliciting tenders of Unionamerica ADSs pursuant to the Offer
(other than to the Information Agent).  Brokers, dealers, commercial banks,
trust companies and other nominees will, upon request, be reimbursed by MMI for
customary mailing and handling expenses incurred by them in forwarding offering
materials to their customers.

ITEM 9.     FINANCIAL STATEMENTS OF CERTAIN BIDDERS.

    The information contained in the following sections of the Prospectus is
incorporated herein by reference:  "Prospectus Summary - Selected Consolidated
Financial Information of MMI", "Prospectus Summary - Selected Pro Forma
Condensed Combined Financial Information", "Unaudited Pro Forma Condensed
Combined Financial Information" and "Incorporation of Certain Documents by
Reference".

ITEM 10.    ADDITIONAL INFORMATION.

    (a)     There are no present or proposed material contracts, arrangements,
understandings or relationships between MMI or any of its executive officers,
directors, controlling persons or subsidiaries and Unionamerica or any of its
executive officers, directors, controlling persons or subsidiaries other than
those disclosed in Items 3 and 7 of this Statement.

    (b)     The information set forth on the Cover Page of the Prospectus, and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition",
"Prospectus Summary - Regulatory Approval Requirements", "Risk Factors", "THE
OFFER - Terms of the Offer and Proposed Acquisition", and "Appendix E - Certain
Additional Information Required Under the City Code" of the Prospectus is
incorporated herein by reference.

    (c)     The information set forth on the Cover Page of the Prospectus, and
in "Prospectus Summary - Summary of the Offer and Proposed Acquisition",
"Prospectus Summary - Regulatory Approval Requirements", "THE OFFER - Terms of
the Offer and Proposed Acquisition", and "Appendix E - Certain Additional
Information Required Under the City Code" of the Prospectus is incorporated
herein by reference.

    (d)     The margin requirements of Section 7 of the Exchange Act and the
regulations promulgated thereunder do not apply to the Offer.

    (e)     There are no material pending legal proceedings relating to the
Offer.

    (f)     There is no material information necessary to make the above
statements, in light of the circumstances under which they are made, not
materially misleading.


                                        - 11 -
<PAGE>

ITEM 11.      MATERIAL TO BE FILED AS EXHIBITS.

    (a)(1)    Prospectus 

    (a)(2)    Letter of Transmittal

    (a)(3)    Notice of Guaranteed Delivery

    (a)(4)    Letter from Smith Barney Inc. to Brokers, Dealers, Commercial
              Banks,Trust Companies and Other Nominees

    (a)(5)    Letter to Clients for use by Brokers, Dealers, Commercial Banks,
              Trust Companies and Other Nominees 

    (a)(6)    Substitute Form W-9 and Guidelines for Certification of Taxpayer
              Name and Identification Number on Substitute Form W-9*

    (a)(7)    Certificate of Foreign Status on Form W-8

    (a)(8)    Recommended Proposals made to Option holders under the
              Unionamerica Holdings plc Unapproved Executive Share Option
              Scheme dated November 6, 1997

    (a)(9)    Acceptance Form for use by Option holders under the 1996 Scheme

    (a)(10)   Recommended Proposals made to Option holders under The
              Unionamerica Holdings plc 1996 Executive Share Option Scheme
              dated November 6, 1997

    (a)(11)   Acceptance Form for use by Option holders under the 1993 Scheme

    (a)(12)   Press Release of MMI dated November 6, 1997

    (a)(13)   Press Release of Unionamerica dated November 6, 1997

    (b)       Not applicable

    (c)(1)    Form of Undertaking

    (c)(2)    Form of Affiliates Agreement

    (c)(3)    Acquisition Agreement dated as of June 25, 1997 by and between
              MMI and Unionamerica**

    (d)(1)    Opinion of Paul, Weiss, Rifkind, Wharton & Garrison


                                        - 12 -
<PAGE>

    (d)(2)    Opinion of Lovell White Durrant

    (e)       See Exhibit (a)(1) hereto.

    (f)       None

__________ 

*Included in Exhibit (a)(2) - Letter of Transmittal

**Included in Exhibit (a)(1) - Appendix A to the Prospectus



    After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this Statement is true, complete and correct.

Dated: November 6, 1997

                                       MMI COMPANIES, INC.



                                       By:  /s/ B. Frederick Becker
                                       Its: Chairman of the Board and 
                                            Chief Executive Officer



                                        - 13 -
<PAGE>

                                    EXHIBIT INDEX

EXHIBIT      EXHIBIT NAME

    (a)(1)    Prospectus 

    (a)(2)    Letter of Transmittal

    (a)(3)    Notice of Guaranteed Delivery

    (a)(4)    Letter from Smith Barney Inc. to Brokers, Dealers, Commercial
              Banks, Trust Companies and Other Nominees

    (a)(5)    Letter to Clients for use by Brokers, Dealers, Commercial Banks,
              Trust Companies and Other Nominees 

    (a)(6)    Substitute Form W-9 and Guidelines for Certification of Taxpayer
              Name and Identification Number on Substitute Form W-9*

    (a)(7)    Certificate of Foreign Status on Form W-8

    (a)(8)    Recommended Proposals made to Option holders under the
              Unionamerica Holdings plc Unapproved Executive Share Option
              Scheme dated November 6, 1997

    (a)(9)    Acceptance Form for use by Option holders under the 1996 Scheme

    (a)(10)   Recommended Proposals made to Option holders under The
              Unionamerica Holdings plc 1996 Executive Share Option Scheme
              dated November 6, 1997

    (a)(11)   Acceptance Form for use by Option holders under the 1993 Scheme

    (a)(12)   Press Release of MMI dated November 6, 1997

    (a)(13)   Press Release of Unionamerica dated November 6, 1997

    (b)       Not applicable

    (c)(1)    Form of Undertaking

    (c)(2)    Form of Affiliates Agreement

    (c)(3)    Acquisition Agreement dated as of June 25, 1997 by and between
              MMI and Unionamerica**


                                        - 14 -
<PAGE>

    (d)(1)    Opinion of Paul, Weiss, Rifkind, Wharton & Garrison

    (d)(2)    Opinion of Lovell White Durrant

    (e)       See Exhibit (a)(1) hereto.

    (f)       None
__________ 

*Included in EXHIBIT (a)(2) - Letter of Transmittal

**Included in EXHIBIT (a)(1) - Appendix A to the Prospectus


                                        - 15 -

<PAGE>
O F F E R T O E X C H A N G E / P R O S P E C T U S
 
                               OFFER TO EXCHANGE
 
                         0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
 
                 FOR EACH OUTSTANDING AMERICAN DEPOSITARY SHARE
                          OF UNIONAMERICA HOLDINGS PLC
 
              REPRESENTING ALL OF THE OUTSTANDING ORDINARY SHARES
                          OF UNIONAMERICA HOLDINGS PLC
 
    This Offer to Exchange/Prospectus (this "Prospectus") is being furnished to
the holders of ordinary shares, nominal value $0.0448 per share (the
"Unionamerica Common Stock") and to the holders of American Depositary Shares,
each representing a share of Unionamerica Common Stock (the "Unionamerica ADSs")
(the Unionamerica ADSs and the Unionamerica Common Stock are together referred
to herein as either the "Unionamerica Securities" or the "Unionamerica ADSs"),
of Unionamerica Holdings plc, a corporation registered in England and Wales
under the Companies Act 1985 of Great Britain, as amended (the "Companies Act")
with registered number 2822469 ("Unionamerica"), in connection with the offer,
upon the terms and subject to the conditions set forth herein and in the related
Letter of Transmittal (collectively, the "Offer"), by MMI Companies, Inc., a
Delaware corporation ("MMI"), to exchange 0.836 shares of MMI common stock, par
value $0.10 per share (the "MMI Common Stock"), for each outstanding
Unionamerica ADS (the "'Exchange Ratio"). Upon consummation of the Offer, and
the subsequent compulsory acquisition of any remaining outstanding Unionamerica
ADSs (the "Compulsory Acquisition"), Unionamerica will become a wholly-owned
Subsidiary of MMI (the "Proposed Acquisition"). Each share of MMI Common Stock
issued in connection with the Offer will be accompanied by a right (a "Right")
which will entitle the registered holder thereof to purchase from MMI a unit
consisting of one one-hundredth of a share (a "Unit") of Series B Junior
Participating Preferred Stock of MMI, par value $20.00 per share (the "Series B
Preferred Stock"), at a purchase price of $75.00 per Unit (the "Purchase
Price"), subject to adjustment, pursuant to a rights agreement between MMI and
ChaseMellon Shareholder Services L.L.C., as Rights Agent (the "Rights
Agreement"). The Offer is being made pursuant to an Acquisition Agreement dated
as of June 25, 1997 by and between MMI and Unionamerica (the "Acquisition
Agreement"). See "Prospectus Summary-- Summary of the Offer and Proposed
Acquisition", "The Offer--Terms of the Offer and Proposed Acquisition" and
Appendix A--"Acquisition Agreement". See Appendix G--"Key Definitions" for
definitions of certain key terms, including some terms not otherwise defined
herein.
 
    THE OFFER WILL EXPIRE AT 12 MIDNIGHT, NEW YORK CITY TIME, ON DECEMBER 5,
1997 UNLESS THE OFFER IS EXTENDED IN ACCORDANCE WITH THE TERMS OF THE
ACQUISITION AGREEMENT (THE "EXPIRATION DATE"). UNIONAMERICA ADSS WHICH ARE
TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE
EXPIRATION DATE (OTHER THAN THOSE UNIONAMERICA ADSS WHICH ARE TENDERED BY
CERTAIN UNIONAMERICA SECURITYHOLDERS (THE "SELLING STOCKHOLDERS") WHO HAVE
EXECUTED IRREVOCABLE UNDERTAKINGS TO ACCEPT THE OFFER (THE "UNDERTAKINGS")
REPRESENTING 50.21% OF THE OUTSTANDING UNIONAMERICA ADSS AS OF OCTOBER 31,
1997). SEE APPENDIX E--"CERTAIN ADDITIONAL INFORMATION REQUIRED UNDER THE CITY
CODE".
 
    At the Expiration Date, including any extension thereof, and satisfaction
or, where permitted, waiver of the Conditions of the Offer, all Unionamerica
ADSs validly tendered and not validly withdrawn will be exchanged.
                               ------------------
 
    UNIONAMERICA SECURITYHOLDERS SHOULD CAREFULLY CONSIDER ALL OF THE FACTORS
SET FORTH IN "RISK FACTORS", COMMENCING ON PAGE 17 OF THIS PROSPECTUS.
                                 -------------
 
    MMI's obligation to exchange shares of MMI Common Stock for Unionamerica
ADSs pursuant to the Offer is subject to a number of Conditions (as defined
below), including (i) the acceptance of the Offer by holders of at least 90% of
the outstanding Unionamerica ADSs; provided, however, that this 90% level may be
reduced by MMI, but only with the prior written consent of Unionamerica, to a
level less than 90% but greater than 50%, (ii) approval of the issuance of MMI
Common Stock by MMI's stockholders, and (iii) regulatory approval in the United
Kingdom (the "U.K.") and in the United States ("U.S."). See "Prospectus
Summary--Summary of the Offer and Proposed Acquisition", "The Offer--Terms of
the Offer and Proposed Acquisition" and Appendix A--"Acquisition Agreement".
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE U.S. SECURITIES
      AND EXCHANGE COMMISSION (THE "COMMISSION") OR ANY STATE SECURITIES
          COMMISSION NOR HAS THE COMMISSION NOR ANY STATE SECURITIES
          COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
             PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
                               CRIMINAL OFFENSE.
 
    THIS PROSPECTUS AND THE OFFER MADE HEREBY DO NOT CONSTITUTE A SOLICITATION
OF ANY PROXIES OR CONSENTS. ANY SUCH SOLICITATIONS WILL BE MADE ONLY PURSUANT TO
SEPARATE PROXY OR CONSENT SOLICITATION MATERIALS COMPLYING WITH THE REQUIREMENTS
OF SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED.
 
    ANY PERSON WHO, ALONE OR ACTING TOGETHER WITH ANY OTHER PERSON(S) PURSUANT
TO ANY AGREEMENT (FORMAL OR INFORMAL), OWNS OR CONTROLS, OR BECOMES THE OWNER OR
CONTROLLER OF, DIRECTLY OR INDIRECTLY, 1% OR MORE OF THE UNIONAMERICA ADSS OR
MMI COMMON STOCK IS REQUIRED, UNDER THE PROVISIONS OF RULE 8 OF THE CITY CODE ON
TAKEOVERS AND MERGERS OF THE U.K. (THE "CITY CODE") TO NOTIFY THE COMPANY
ANNOUNCEMENTS OFFICE OF THE LONDON STOCK EXCHANGE (THE "LSE") WHICH WILL NOTIFY
THE PANEL ON TAKEOVERS AND MERGERS OF THE U.K. (THE "PANEL") AND THE U.K. PRESS,
OF EVERY DEALING IN ANY UNIONAMERICA ADSS OR MMI COMMON STOCK UNTIL SUCH TIME AS
THE OFFER IS DECLARED UNCONDITIONAL OR LAPSES, IN ACCORDANCE WITH RULE 8.
DEALINGS BY "ASSOCIATES" (WITHIN THE MEANING OF THE CITY CODE) OF MMI OR
UNIONAMERICA IN MMI COMMON STOCK OR UNIONAMERICA ADSS DURING THE INITIAL OFFER
PERIOD MUST ALSO BE DISCLOSED. PLEASE CONSULT YOUR LEGAL COUNSEL IF YOU BELIEVE
RULE 8 MAY BE APPLICABLE TO YOU.
 
The Dealer Manager for the Offer is Smith Barney Inc.
 
The date of this Prospectus is November 5, 1997
<PAGE>
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
Available Information.....................................................     1
Incorporation of Certain Documents by Reference...........................     1
Forward-Looking Statements................................................     3
Prospectus Summary........................................................     4
  Summary of the Offer and Proposed Acquisition...........................     4
  Description of MMI......................................................     7
  Description of Unionamerica.............................................     8
  Selected Consolidated Financial Information of MMI......................     9
  Selected Consolidated Financial Information of Unionamerica.............    10
  Selected Pro Forma Condensed Combined Financial Information.............    12
  Comparative Historical and Pro Forma Per Share Data.....................    13
  Market Price of MMI Common Stock and Unionamerica ADSs..................    13
  MMI Common Stock and Unionamerica ADSs Held by Directors, Executive
    Officers, and Their Affiliates........................................    14
  Regulatory Approval Requirements........................................    15
  Dissenters' Rights......................................................    15
  Tax Consequences of the Offer...........................................    16
Risk Factors..............................................................    17
The Offer.................................................................    21
  Background of the Proposed Acquisition..................................    21
  Terms of the Offer and Proposed Acquisition.............................    23
  Procedures for Tendering Unionamerica ADSs..............................    31
  Extensions; Amendments; and Termination.................................    35
  MMI's Reasons for the Proposed Acquisition and Recommendation of the MMI
    Board.................................................................    39
  Opinion of Financial Advisor to MMI.....................................    40
  Unionamerica's Reasons for the Proposed Acquisition and Recommendation
    of the Unionamerica Board.............................................    44
  Opinion of Financial Advisor to Unionamerica............................    46
  Proposed Refinancing of Bank Debt.......................................    52
  Description of MMI Capital Stock........................................    53
  Description of Unionamerica Capital Stock...............................    55
  Changes in the Rights of Unionamerica Securityholders...................    57
  Accounting Treatment....................................................    69
  Tax Consequences of the Offer...........................................    69
  Material Contracts between MMI and Unionamerica.........................    72
Unaudited Pro Forma Condensed Combined Financial Information..............    73
  Unaudited Pro Forma Condensed Combined Balance Sheet as of June 30,
    1997..................................................................    74
  Unaudited Pro Forma Condensed Combined Statement of Income for the six
    months ended June 30, 1997............................................    75
  Unaudited Pro Forma Condensed Combined Statement of Income for the six
    months ended June 30, 1996............................................    76
</TABLE>
 
                                       i
<PAGE>
<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
  Unaudited Pro Forma Condensed Combined Statement of Income for the year
    ended December 31, 1996...............................................    77
  Unaudited Pro Forma Condensed Combined Statement of Income for the year
    ended December 31, 1995...............................................    78
  Unaudited Pro Forma Condensed Combined Statement of Income for the year
    ended December 31, 1994...............................................    79
  Notes to Unaudited Pro Forma Condensed Combined Financial Information...    80
Legal Matters.............................................................    81
Experts...................................................................    81
Appendices
  A Acquisition Agreement
  B Opinion of Smith Barney Inc., Financial Advisor to MMI
  C Opinion of Donaldson Lufkin & Jenrette Securities Corporation,
      Financial Advisor to Unionamerica
  D Certain Market, Dividend and Exchange Rate Information
  E Certain Additional Information Required Under the City Code
  F Certain Provisions of the Companies Act
  G Key Definitions
</TABLE>
 
                                       ii
<PAGE>
                             AVAILABLE INFORMATION
 
    MMI has filed with the Commission a Registration Statement on Form S-4 (the
"Registration Statement") under the Securities Act of 1933, as amended (such Act
and the rules and regulations promulgated thereunder being referred to herein as
the "Securities Act"), with respect to the shares of MMI Common Stock offered
hereby. This Prospectus, which forms part of the Registration Statement, does
not contain all of the information set forth in the Registration Statement and
the exhibits and financial statements thereto, certain portions of which have
been omitted pursuant to the rules and regulations of the Commission, to which
portions reference is hereby made. Statements contained in this Prospectus as to
the contents of any contract, agreement or other document are summaries which
are not necessarily complete, and in each instance reference is made to the copy
of such contract, agreement or other document filed as an appendix to this
Prospectus or as an exhibit to the Registration Statement, each such statement
herein being qualified in all respects by such reference.
 
    MMI and Unionamerica are subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (such Act and the rules and
regulations promulgated thereunder being referred to herein as the "Exchange
Act"), and in accordance therewith, file annual and quarterly reports, proxy
statements (in the case of MMI) and other information with the Commission. Such
reports, proxy statements, other information and the Registration Statement,
including all exhibits thereto, may be inspected without charge and copied at
the public reference facilities of the Commission at its principal office at
Judiciary Plaza, 450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549, and
at its regional offices at Citicorp Center, 500 West Madison Street, Suite 1400,
Chicago, Illinois 60661 and at Seven World Trade Center, 13th Floor, New York,
New York 10048. Any interested party may obtain copies of all or any portion of
the Registration Statement and its exhibits at prescribed rates from the Public
Reference Section of the Commission at its principal office at Judiciary Plaza,
450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549. In addition, reports,
proxy statements, other information and this Registration Statement may be
inspected at the offices of the New York Stock Exchange, Inc. (the "NYSE"), 20
Broad Street, New York, New York 10005.
 
    Not earlier than the date of commencement of the Offer, MMI will file with
the Commission a statement on Schedule 14D-1 pursuant to Rule 14d-3 under the
Exchange Act furnishing certain information with respect to the Offer. Pursuant
to Rules 14d-9 and 14e-2 under the Exchange Act, Unionamerica will file a
statement on Schedule 14D-9 furnishing certain information with respect to its
position concerning the Offer. Such Schedules (together with all exhibits
thereto) and any amendments thereto shall be available for inspection and
copying as set forth above (except that such Schedules and amendments thereto
will not be available at the regional offices of the Commission).
 
    The Commission maintains a World Wide Web site on the Internet at
http://www.sec.gov that contains reports, proxy and information statements and
other information regarding registrants, such as MMI, that file electronically
with the Commission.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
    The following documents have been filed by MMI (File No. 1-11920) with the
Commission and are incorporated herein by reference: (i) MMI's Annual Report on
Form 10-K for the year ended December 31, 1996, as amended to date; (ii) MMI's
Quarterly Report on Form 10-Q for the quarter ended March 31, 1997, as amended
to date; (iii) MMI's Quarterly Report on Form 10-Q for the quarter ended June
30, 1997, as amended to date; (iv) MMI's Proxy Statement for the annual meeting
of stockholders held on April 17, 1997; (v) the description of Common Stock
contained in MMI's Registration Statement on Form 8-A filed April 28, 1993,
pursuant to Section 12 of the Exchange Act and all amendments thereto filed for
the purpose of updating such description; (vi) the description of the MMI
Shareholder Rights Plan contained in MMI's Registration Statement on Form 8-A
filed June 27, 1997; and (vii) MMI's Current Reports on Form 8-K dated June 25,
1997 and filed June 27, 1997, and dated June 17, 1997 and filed
 
                                       1
<PAGE>
June 18, 1997. All documents filed by MMI with the Commission pursuant to
Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, subsequent to the date
of this Prospectus and prior to the termination of the Offer, shall be deemed to
be incorporated by reference into this Prospectus. Any statement contained
herein or in a document incorporated or deemed to be incorporated by reference
herein shall be deemed to be modified or superseded for purposes of this
Prospectus to the extent that a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated by
reference herein, modifies or supersedes such statement. Any statement or
document so modified or superseded shall not be deemed, except as so modified or
superseded, to constitute a part of this Prospectus.
 
    THIS PROSPECTUS INCORPORATES DOCUMENTS OF MMI BY REFERENCE WHICH ARE NOT
PRESENTED HEREIN OR DELIVERED HEREWITH. THESE DOCUMENTS (OTHER THAN EXHIBITS TO
SUCH DOCUMENTS WHICH ARE NOT SPECIFICALLY INCORPORATED BY REFERENCE IN SUCH
DOCUMENTS) ARE AVAILABLE FROM MMI, UPON WRITTEN OR ORAL REQUEST, WITHOUT CHARGE,
TO EACH PERSON (INCLUDING ANY BENEFICIAL OWNER) TO WHOM THIS PROSPECTUS IS
DELIVERED. REQUESTS SHOULD BE DIRECTED TO MMI COMPANIES, INC., 540 LAKE COOK
ROAD, DEERFIELD, ILLINOIS 60015, ATTENTION: INVESTOR RELATIONS, TELEPHONE (847)
374-2254. IN ORDER TO ENSURE TIMELY DELIVERY OF THE DOCUMENTS, ANY REQUEST
SHOULD BE MADE NO LATER THAN FIVE BUSINESS DAYS PRIOR TO THE EXPIRATION DATE.
 
    The following documents have been filed by Unionamerica (File No. 1-14112)
with the Commission and are incorporated herein by reference: (i) Unionamerica's
Annual Report on Form 10-K for the year ended December 31, 1996, as amended to
date; (ii) Unionamerica's Quarterly Report on Form 10-Q for the quarter ended
March 31, 1997; (iii) Unionamerica's Quarterly Report on Form 10-Q for the
quarter ended June 30, 1997; (iv) the description of Unionamerica Common Stock
contained in Unionamerica's Registration Statement on Form 8-A filed November
30, 1995, pursuant to Section 12 of the Exchange Act and all amendments thereto
filed for the purpose of updating such description; and (v) Unionamerica's
Current Report on Form 8-K dated June 2, 1997 and filed June 11, 1997. All
documents filed by Unionamerica with the Commission pursuant to Sections 13(a),
13(c), 14 or 15(d) of the Exchange Act, subsequent to the date of this
Prospectus and prior to the termination of the Offer, shall be deemed to be
incorporated by reference into this Prospectus. Any statement contained herein
or in a document incorporated or deemed to be incorporated by reference herein
shall be deemed to be modified or superseded for purposes of this Prospectus to
the extent that a statement contained herein or in any other subsequently filed
document which also is or is deemed to be incorporated by reference herein,
modifies or supersedes such statement. Any statement or document so modified or
superseded shall not be deemed, except as so modified or superseded, to
constitute a part of this Prospectus.
 
    THIS PROSPECTUS INCORPORATES DOCUMENTS OF UNIONAMERICA BY REFERENCE WHICH
ARE NOT PRESENTED HEREIN OR DELIVERED HEREWITH. THESE DOCUMENTS (OTHER THAN
EXHIBITS TO SUCH DOCUMENTS WHICH ARE NOT SPECIFICALLY INCORPORATED BY REFERENCE
IN SUCH DOCUMENTS) ARE AVAILABLE FROM UNIONAMERICA, UPON WRITTEN OR ORAL
REQUEST, WITHOUT CHARGE, TO EACH PERSON (INCLUDING ANY BENEFICIAL OWNER) TO WHOM
THIS PROSPECTUS IS DELIVERED. REQUESTS SHOULD BE DIRECTED TO UNIONAMERICA
HOLDINGS PLC, LONDON UNDERWRITING CENTRE, 3 MINSTER COURT, MINCING LANE, LONDON
EC3R 7DD, ENGLAND ATTENTION: TREVOR R. SMITH, TELEPHONE +44-171-617-5959. IN
ORDER TO ENSURE TIMELY DELIVERY OF THE DOCUMENTS, ANY REQUEST SHOULD BE MADE NO
LATER THAN FIVE BUSINESS DAYS PRIOR TO THE EXPIRATION DATE.
 
    NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR MAKE ANY
REPRESENTATION IN CONNECTION WITH THE OFFER OTHER THAN THOSE CONTAINED OR
INCORPORATED BY REFERENCE IN THIS PROSPECTUS, AND, IF GIVEN OR MADE, SUCH
INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED
BY MMI OR THE DEALER MANAGER. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER OR A
SOLICITATION TO ANY PERSON IN ANY JURISDICTION IN WHICH SUCH OFFER OR
SOLICITATION IS UNLAWFUL. THE OFFER IS NOT BEING MADE TO, NOR WILL TENDERS BE
ACCEPTED FROM OR ON BEHALF OF, UNIONAMERICA SECURITYHOLDERS IN ANY JURISDICTION
IN WHICH THE MAKING OR ACCEPTANCE
 
                                       2
<PAGE>
THEREOF WOULD NOT BE IN COMPLIANCE WITH THE LAWS OF SUCH JURISDICTION. HOWEVER,
MMI MAY, IN ITS SOLE DISCRETION, TAKE SUCH ACTION AS IT MAY DEEM NECESSARY TO
MAKE THE OFFER IN ANY SUCH JURISDICTION AND EXTEND THE OFFER TO UNIONAMERICA
SECURITYHOLDERS IN SUCH JURISDICTIONS. NEITHER THE DELIVERY OF THIS PROSPECTUS
NOR ANY EXCHANGE HEREUNDER SHALL UNDER ANY CIRCUMSTANCES CREATE ANY IMPLICATION
THAT THERE HAS BEEN NO CHANGE IN THE AFFAIRS OF MMI OR UNIONAMERICA SINCE THE
DATE AS OF WHICH INFORMATION IS FURNISHED OR THE DATE HEREOF.
 
    IN ANY JURISDICTION WHERE THE SECURITIES, BLUE SKY OR OTHER LAWS REQUIRE THE
OFFER TO BE MADE BY A LICENSED BROKER OR DEALER, THE OFFER SHALL BE DEEMED TO BE
MADE ON BEHALF OF MMI BY SMITH BARNEY, AS DEALER MANAGER, OR ONE OR MORE
REGISTERED BROKERS OR DEALERS LICENSED UNDER THE LAWS OF SUCH JURISDICTION.
 
                           FORWARD-LOOKING STATEMENTS
 
    This Prospectus includes forward-looking statements. All statements
regarding MMI's or Unionamerica's expected future financial position, business
strategy, budgets, projected costs, and plans and objectives of management for
future operations, are forward-looking statements. Although MMI and Unionamerica
believe their respective expectations reflected in such forward-looking
statements are based on reasonable assumptions, no assurance can be given that
such expectations will prove to have been correct. Important factors that could
cause actual results to differ materially from the expectations reflected in the
forward-looking statements herein include, among others, those set forth under
"Risk Factors", general economic and business and market conditions, changes in
U.S. and non-U.S. laws and regulations with respect to the insurance and
reinsurance industries, difficulties in achieving expected cost savings from the
Proposed Acquisition or costs or difficulties relating to the integration of
MMI's and Unionamerica's businesses, increased competitive and/or customer
pressure in the insurance and reinsurance industries and the ability of MMI and
Unionamerica to achieve the goals described in "MMI's Reasons for the Proposed
Acquisition and Recommendation of the MMI Board".
 
                                       3
<PAGE>
                               PROSPECTUS SUMMARY
 
    THE FOLLOWING SUMMARY IS QUALIFIED IN ITS ENTIRETY BY THE MORE DETAILED
INFORMATION AND THE FINANCIAL STATEMENTS AND NOTES THERETO APPEARING ELSEWHERE
IN THIS PROSPECTUS OR INCORPORATED BY REFERENCE. ALL FINANCIAL DATA FOR MMI AND
UNIONAMERICA ARE PRESENTED ON THE BASIS OF U.S. GENERALLY ACCEPTED ACCOUNTING
PRINCIPLES ("GAAP") UNLESS OTHERWISE STATED. UNLESS THE CONTEXT OTHERWISE
INDICATES, ALL REFERENCES TO "MMI" REFER TO MMI COMPANIES, INC. AND ITS
SUBSIDIARIES, AND ALL REFERENCES TO "UNIONAMERICA" REFER TO UNIONAMERICA
HOLDINGS PLC AND ITS SUBSIDIARIES. SEE APPENDIX G TO THIS PROSPECTUS--"KEY
DEFINITIONS", FOR DEFINITIONS OF CERTAIN KEY TERMS, INCLUDING SOME TERMS NOT
OTHERWISE DEFINED HEREIN.
 
SUMMARY OF THE OFFER AND PROPOSED ACQUISITION
 
    INTRODUCTION.  On June 25, 1997, MMI and Unionamerica entered into an
Acquisition Agreement pursuant to which, subject to the terms and conditions
stated therein and in this Prospectus and the accompanying Letter of
Transmittal, MMI agreed to offer 0.836 shares of MMI Common Stock for each
outstanding Unionamerica ADS. This Prospectus contains the formal offer by MMI.
 
    THE OFFER.  MMI hereby offers to acquire, on the terms and subject to the
conditions set out in this Prospectus and the accompanying Letter of Transmittal
(including if the Offer is revised, varied, extended or renewed, the terms and
conditions of any such revision, variation, extension or renewal), each
outstanding share of Unionamerica Common Stock (including shares represented by
Unionamerica ADSs) in exchange for 0.836 shares of MMI Common Stock. Each share
of MMI Common Stock issued in connection with the Offer will be accompanied by a
Right which will entitle the registered holder thereof to purchase from MMI a
Unit of Series B Preferred Stock at a purchase price of $75.00 per Unit (the
"Purchase Price"), subject to adjustment, pursuant to the Rights Agreement. The
Offer which is being made to all Unionamerica Securityholders (including U.S.
Persons) will remain open until the Expiration Date, including any extension
thereof. The Offer and this Prospectus are subject to the requirements of both
the Panel and the Commission.
 
    MARKET PRICE OF MMI COMMON STOCK AND UNIONAMERICA ADSS.  On October 31, 1997
(being the latest practicable date prior to the filing of this Prospectus with
the Commission) the closing price of MMI Common Stock on the NYSE was $24.94 per
share and the closing price of Unionamerica ADSs on the NYSE was $19.88 per ADS.
 
    UNDERTAKINGS.  MMI has received undertakings (the "Undertakings") to accept
the Offer, subject to certain conditions, from the Selling Stockholders in
respect of not less than an aggregate of 4,272,983 Unionamerica ADSs
(representing 50.21% of Unionamerica's outstanding ADSs as of October 31, 1997).
For further information regarding these Undertakings, see Appendix E--"Certain
Additional Information Required Under the City Code".
 
    NO FRACTIONAL SHARES.  Cash will be paid to Unionamerica Securityholders in
lieu of any entitlements to fractional shares of MMI Common Stock to be issued
upon the surrender for exchange of Unionamerica ADSs. All fractional shares to
be issued in the Offer will be aggregated and sold by the Exchange Agent for the
benefit of the Unionamerica Securityholders receiving such fractional shares.
See "The Offer-- Terms of the Offer and Proposed Acquisition".
 
    DEFERRED STOCK.  At the consummation of the Offer, Unionamerica will, in
accordance with Article 5 of the Articles of Association of Unionamerica (the
"Unionamerica Articles"), cause all of the issued and outstanding shares of
deferred stock of Unionamerica, par value L1 per share (the "Deferred Stock"),
to be transferred to MMI (with the exception of one share of Deferred Stock
which will be transferred to a Person designated by MMI to hold such share as
nominee for MMI) in exchange for one share of MMI Common Stock for each 25,000
shares of Deferred Stock outstanding. As of the date of this Prospectus,
Unionamerica has 50,000 shares of Deferred Stock outstanding.
 
                                       4
<PAGE>
    ACQUISITION OF REMAINING UNIONAMERICA ADSS.  Following the Offer becoming or
being declared unconditional in all respects, if MMI has received acceptances
constituting not less than 90% of the outstanding Unionamerica ADSs, MMI shall
be entitled, and intends, to apply the provisions of Sections 428 to 430F of the
Companies Act to effect the Compulsory Acquisition and acquire compulsorily any
outstanding Unionamerica ADSs. See "The Offer--Terms of the Offer and Proposed
Acquisition", "Prospectus Summary--Dissenters' Rights--Unionamerica", and
Appendix E--"Certain Additional Information Required Under the City Code".
 
    PROPOSED ACQUISITION.  Following the closing of the Proposed Acquisition,
Unionamerica will become a wholly-owned Subsidiary of MMI. It is MMI's present
intention to continue the existing management and business plans of Unionamerica
after the Proposed Acquisition, and to continue to operate Unionamerica as a
distinct business entity at its present location in London.
 
    MMI COMMON STOCK.  The shares of MMI Common Stock to be issued pursuant to
the Offer will rank PARI PASSU in all respects with the issued and outstanding
MMI Common Stock, including the right to receive all future dividends (payable
in U.S. dollars), if any, and other distributions, having a record date after
the Expiration Date, including any extension thereof. Application will be made
to list the MMI Common Stock to be issued in connection with the Offer on the
NYSE.
 
    TAX TREATMENT.  MMI and Unionamerica intend that the exchange of shares of
MMI Common Stock for Unionamerica ADSs pursuant to the Offer will be treated as
a tax-free reorganization as described in Section 368(a)(1)(B) of the Internal
Revenue Code of 1986, as amended (the "IRC"). See "The Offer-- Tax Consequences
of the Offer".
 
    POOLING-OF-INTERESTS ACCOUNTING TREATMENT.  It is contemplated that the
Proposed Acquisition will be accounted for as a pooling-of-interests for
accounting purposes under GAAP. Under this accounting treatment, the accounts of
MMI and the accounts of Unionamerica will be combined for all past and future
periods presented after the Offer becomes or is declared unconditional in all
respects.
 
    AFFILIATES' RESTRICTIONS ON SALE OF SHARES OF MMI COMMON STOCK.  The shares
of MMI Common Stock to be issued pursuant to the Offer have been registered
under the Securities Act pursuant to a Registration Statement on Form S-4,
thereby allowing such securities to be traded without restriction by any former
holder of Unionamerica ADSs if such former holder (i) is not deemed to be an
"affiliate" (as defined for the purposes of Rule 144 under the Securities Act)
of Unionamerica within 30 days prior to the date the Offer is declared
unconditional in all respects, and (ii) does not become an affiliate or officer
of MMI pursuant to the Offer.
 
    In order to ensure that one of the requirements of pooling-of-interests
accounting is met, certain directors and executive officers of Unionamerica have
executed and delivered, and prior to the date of this Prospectus, certain other
directors and executive officers shall have executed and delivered, an Affiliate
Letter to MMI, pursuant to which they agreed not to sell any shares of MMI
Common Stock or Unionamerica Securities during the time period that would cause
the violation of the requirements for pooling-of-interests accounting, which
period ends when the financial results of the combined operations of MMI and
Unionamerica covering a period of at least 30 days are publicly released by MMI.
 
    ELECTION OF REPRESENTATIVES TO THE MMI BOARD.  MMI has agreed that, at or
prior to the consummation of the Proposed Acquisition, MMI shall increase the
size of its Board by two members to 14 members. Upon consummation of the
Proposed Acquisition, MMI shall use its best efforts to nominate both Ian G.
Sinclair and Robert A. Spass to the MMI Board. At MMI's 1998 Annual Meeting of
Stockholders, MMI shall use its best efforts to nominate the aforesaid
individuals to the MMI Board and cause them to be elected to one full three-year
term. Ian G. Sinclair was Managing Director-Underwriting of Unionamerica
Insurance Company Limited, a wholly-owned subsidiary of Unionamerica ("UICL"),
from 1984 until December 31, 1996, when he was appointed Chief Executive Officer
of UICL. He has been a Director of
 
                                       5
<PAGE>
UICL since 1977 and of Unionamerica since September 10, 1993. From 1973 to 1977,
he was an underwriter with UICL focusing on casualty business. Robert A. Spass
has been a Director of Unionamerica since September 10, 1993. From February 1994
to the present, he has served as a founder and Managing Partner of Insurance
Partners Advisors, L.P. ("IPA"). From March 1990 to the present, he has been
President and Chief Executive Officer of International Insurance Advisors, Inc.
("IIA"). From December 1988 to March 1990, he was a Director of Salomon Brothers
Inc. He is also a Director of Superior National Insurance Group, Inc., Highlands
Insurance Group Inc., Tarquin plc and Charman Group Ltd.
 
    UNIONAMERICA OPTIONS.  The Offer extends to any Unionamerica ADSs
representing any shares of Unionamerica Common Stock which are unconditionally
issued or allotted upon the exercise of options granted under the Unionamerica
Share Option Schemes or otherwise while the Offer remains open for acceptance.
In addition, a proposal is being made to Option holders under the Unionamerica
Share Option Schemes in respect of unexercised options which will, in the event
the Offer becomes or is declared unconditional, enable Option holders to cancel
their options in return for the grant of a comparable option to purchase MMI
Common Stock. See "The Offer--Terms of the Offer and Proposed Acquisition".
 
    CONDITIONS OF THE OFFER.  The Offer is conditioned upon, among other things,
(i) MMI having received valid tenders pursuant to the Offer (which have not been
validly withdrawn) in respect of not less than 90% on a fully diluted basis in
nominal value of the Unionamerica ADSs (the "Minimum Acceptance Condition"), as
described in "The Offer--Terms of the Offer and Proposed Acquisition"; except
that, with the prior written consent of Unionamerica, the Minimum Acceptance
Condition may be reduced by MMI (insofar as this does not have the effect of
reducing the threshold specified above to an amount which is 50% or less) (any
voting rights attributable to any Unionamerica ADSs representing any shares of
Unionamerica Common Stock which are unconditionally allotted or issued fully
paid (including pursuant to the exercise of options granted under the
Unionamerica Share Option Schemes or otherwise) after the date of this
Prospectus and while the Offer remains open for acceptance are included for the
purpose of determining the Minimum Acceptance Condition); (ii) the approval of
the issuance of shares of MMI Common Stock pursuant to the Offer and the
Acquisition Agreement and the transactions contemplated therein by a majority of
the outstanding shares of MMI Common Stock voting on such matter (MMI, through
its Board of Directors (the "MMI Board"), will duly call, give notice of,
convene and hold a meeting of its stockholders (the "MMI Special Meeting") for
the purpose of approving the issuance of MMI Common Stock contemplated by the
Proposed Acquisition (the "MMI Stockholders' Approval") as soon as reasonably
practicable after the date of this Prospectus); (iii) the MMI Common Stock to be
issued pursuant to the Offer and such of the shares of MMI Common Stock required
to be reserved for issuance pursuant to the Acquisition Agreement, if any, being
approved for listing on the NYSE and the listing having become effective,
subject to official notice of issuance; and (iv) the Unionamerica
Securityholders approving and adopting a resolution at an extraordinary general
meeting of Unionamerica (or at any adjournment thereof) to amend the
Unionamerica Articles to disapply certain voting restrictions contained in
Articles 75 and 76 which would otherwise apply to MMI following the closing of
the Proposed Acquisition. See "The Offer--Terms of the Offer and Proposed
Acquisition--Conditions of the Offer".
 
    OFFER PERIOD.  The Offer will commence at 12:01 a.m., New York City time on
November 6, 1997 and will expire at 12 midnight, New York City time, on December
5, 1997, unless extended. Following the Expiration Date, including any extension
thereof and satisfaction or, where permitted, waiver of the Conditions, all
Unionamerica ADSs validly tendered and not validly withdrawn will be exchanged.
 
    WITHDRAWAL RIGHTS.  Unionamerica Securityholders (other than the Selling
Stockholders) will have the right to withdraw any tendered Unionamerica ADSs at
all times during the pendency of the Offer, until the Expiration Date, including
any extension thereof. Subject to the terms of the Acquisition Agreement, MMI
expressly reserves the right (but will not be obligated) at any time or from
time to time to extend the Offer in the manner described in "The Offer--Terms of
the Offer and Proposed Acquisition".
 
                                       6
<PAGE>
    CERTAIN CONSEQUENCES OF THE OFFER.  The purchase of Unionamerica ADSs
pursuant to the Offer will reduce the number of Unionamerica Securityholders and
the number of Unionamerica ADSs that might otherwise trade publicly and,
depending on the number of Unionamerica ADSs so purchased, could adversely
affect the liquidity and market value of the remaining Unionamerica ADSs held by
the public. In addition, Unionamerica ADSs will cease to be quoted on the NYSE
if MMI is entitled to and does effect the Compulsory Acquisition. Even if the
Compulsory Acquisition is not effected, there would be a delisting from the NYSE
if certain minimum requirements with respect to the number of publicly held
shares and/or the number of public shareholders or other criteria are not met.
The Unionamerica ADSs may also be deregistered under the Exchange Act if minimum
requirements with respect to the number of shareholders of record are not met,
with a consequent termination of certain public reporting obligations in the
U.S.
 
    RECOMMENDATION OF THE OFFER.  The Board of Directors of Unionamerica (the
"Unionamerica Board") has determined that the terms of the Offer are fair and
reasonable to holders of Unionamerica ADSs. The Unionamerica Board has
unanimously recommended the Offer to the Unionamerica Securityholders. For a
discussion of the factors taken into consideration by the Unionamerica Board,
see "Unionamerica's Reasons for the Proposed Acquisition and Recommendation of
the Unionamerica Board".
 
    TAX CONSEQUENCES TO UNIONAMERICA SECURITYHOLDERS.  Certain tax consequences
to Unionamerica Securityholders in the U.S. and the U.K. of (i) the exchanges
pursuant to the Offer, and (ii) the receipt, ownership and disposal of MMI
Common Stock are described below under "The Offer--Tax Consequences of the
Offer". Unionamerica Securityholders should consult their own tax advisors
concerning the tax consequences and any tax reporting requirements applicable in
light of their particular circumstances.
 
    PROPOSED REFINANCING OF BANK DEBT.  MMI presently is considering, subject to
market conditions, to refinance the combined bank debt of MMI and Unionamerica
after closing the Proposed Acquisition (approximately $103 million) through a
private placement to institutional investors of approximately $100 million of
preferred trust securities during November or December 1997, which will not be
registered under the Securities Act and may not be offered and sold in the U.S.
absent registration or an applicable exemption from registration requirements.
There is no assurance that MMI will decide to proceed with such refinancing. The
offering will be made through the issuance of MMI non-callable, junior
subordinated debentures maturing in 2027, an MMI guarantee, and the related
issuance of capital securities by a Delaware business trust to be formed by MMI
(the debentures, guarantee, and capital securities collectively referred to
herein as the "Refinancing Securities"). MMI intends to file a registration
statement for an exchange offer for the Refinancing Securities. See
"--Description of MMI Capital Stock" and "Appendix D" for a description of
restrictions on dividends and distributions on, and purchases of, MMI Common
Stock in the event MMI elects to defer the payment of interest on the
subordinated debentures. MMI has no present intention to elect to defer interest
payments on the subordinated debentures.
 
DESCRIPTION OF MMI
 
    MMI offers a comprehensive set of specialized insurance products and
consulting services that are designed to assist healthcare providers manage the
business, clinical, insurable and financial risks associated with the delivery
of healthcare. MMI had total revenues of $243.2 million in 1996, including net
premiums earned of $164.4 million and consulting and fee income of $34.5
million, and net income of $21.0 million.
 
    MMI's business is organized into three operating groups:
 
       The INSURANCE GROUP generates medical malpractice and life and health
       insurance premiums by underwriting primarily professional and general
       liability insurance and reinsurance for healthcare providers, including
       hospitals, healthcare systems and physician groups.
 
       The STRATEGIC MANAGEMENT CONSULTING GROUP generates fee income by
       providing healthcare clients with consulting services, including strategy
       development, healthcare system integration and
 
                                       7
<PAGE>
       development, managed care strategy design and implementation,
       hospital/physician alignment strategies and business process
       reengineering.
 
       The HEALTHCARE SERVICES GROUP generates fee income by providing clinical
       risk modification services, employee relations and human resource
       consulting services, education programs, information services, managed
       care and third party administrative services, physician credentials
       verification and patient billing and coding services.
 
    MMI is a Delaware corporation with its principal office located at 540 Lake
Cook Road, Deerfield, Illinois, 60015. MMI's telephone number is (847) 940-7550.
 
    For additional information regarding MMI, see documents filed with the
Commission under "Incorporation of Certain Documents by Reference".
 
DESCRIPTION OF UNIONAMERICA
 
    Founded in 1971, Unionamerica is a specialty casualty and property reinsurer
and insurer operating in the London-based reinsurance and insurance market.
Unionamerica's core business is professional indemnity reinsurance (including
malpractice reinsurance for groups of healthcare providers, lawyers and other
professionals), as well as casualty reinsurance and insurance for a variety of
U.S. single industry and/or single state risks. In addition, Unionamerica
selectively underwrites other risks where it has underwriting expertise and when
management believes market conditions relating to pricing and terms are
attractive. In 1996, these coverages primarily included individual property
risk, automobile physical damage and property catastrophe coverages. Of the
$153.2 million of gross premiums written by Unionamerica in 1996 (stated before
a prior year adjustment of $7.3 million, mainly as a result of adjustments in
estimates for Unionamerica's 1995 surplus lines premium income), 80.1% were in
specialty casualty lines, 63.7% were in reinsurance and 83.2% were attributable
to U.S. insureds and reinsureds. In 1996, Unionamerica had revenues of $145.5
million, which included net premiums earned of $117.0 million. Unionamerica's
net income in 1996 totalled $19.1 million.
 
    Unionamerica is a holding company registered in England and Wales under the
Companies Act with registered number 2822469. Its registered office and
principal place of business is located at 3 Minster Court, Mincing Lane, London
EC3R 7DD, England. Unionamerica's telephone number is +44-171-617-5959.
 
    For additional information regarding Unionamerica, see documents filed with
the Commission under "Incorporation of Certain Documents by Reference".
 
                                       8
<PAGE>
SELECTED CONSOLIDATED FINANCIAL INFORMATION OF MMI
 
    The following table sets forth selected consolidated financial information
of MMI for each of the years in the five-year period ended December 31, 1996 and
for each of the six month periods ended June 30, 1996 and 1997. The balance
sheet data as of December 31, 1992, 1993, 1994, 1995 and 1996 and the premium
and income data for the years ending December 31, 1992, 1993, 1994, 1995 and
1996 are derived from the audited consolidated financial statements of MMI. The
selected data as of and for each of the six month periods ended June 30, 1996
and 1997 has been derived from the unaudited consolidated financial statements
of MMI. In the opinion of MMI's management, the unaudited consolidated financial
information includes all adjustments necessary for a fair presentation of the
financial position and results of operations for such periods. The selected
consolidated financial information should be read in conjunction with MMI's
consolidated financial statements and notes thereto incorporated by reference in
this Prospectus.
 
<TABLE>
<CAPTION>
                                                                                               SIX MONTHS ENDED
                                                     YEAR ENDED DECEMBER 31,                       JUNE 30,
                                      -----------------------------------------------------  --------------------
                                       1992(1)     1993      1994(2)     1995       1996       1996       1997
                                      ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                                  (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS AND RATIOS)
<S>                                   <C>        <C>        <C>        <C>        <C>        <C>        <C>
PREMIUMS AND INCOME DATA:
Gross premiums written..............  $ 136,774  $ 161,421  $ 184,791  $ 210,752  $ 214,326  $ 131,408  $ 130,497
Net premiums written................    102,350    120,237    139,800    161,188    167,392    100,225     99,960
Net premiums earned.................    100,894    116,295    132,389    155,191    164,409     81,824     78,311
Consulting and fee income...........      5,924      6,962     18,602     22,336     34,535     15,628     25,308
Net investment income...............     28,603     29,836     29,067     39,850     44,274     21,653     23,288
Total revenues......................    142,074    154,864    177,205    218,744    243,178    120,107    128,537
Income from continuing
  operations(3).....................      6,683     14,181     15,051     22,695     26,115     13,759     13,520
  Per share(4)......................       1.01       1.90       1.72       2.34       2.42       1.34       1.13
Cash dividends per common share.....       0.11       0.12       0.16       0.20       0.24       0.12       0.14
Weighted average number of common
  and common equivalent shares(4)...      6,613      7,483      8,763      9,683     10,770     10,276     12,007
BALANCE SHEET DATA (AT END OF
  PERIOD):
Cash and investments................  $ 414,775  $ 472,754  $ 498,177  $ 744,061  $ 789,530  $ 715,345  $ 766,099
Total assets........................    558,998    643,773    693,804    982,678  1,058,018  1,004,199  1,088,051
Loss and loss adjustment expense
  reserves..........................    384,621    419,679    448,672    638,815    631,573    626,340    631,928
Long-term debt......................     23,000     16,000     28,000     49,000     58,000     58,000     58,000
Net unrealized gains (losses) on
  investments.......................     --         --         (7,237)    18,490     12,791      4,024     11,801
Stockholders' equity................     76,966    116,503    123,059    186,463    251,966    187,946    263,199
Book value per share................      11.96      13.56      14.28      19.27      21.67      19.05      22.59
GAAP RATIOS(5):
Loss ratio..........................       86.6%      87.3%      85.1%      83.8%      82.6%      82.8%      82.2%
Expense ratio.......................       36.5       22.6       20.3       22.1       23.0       22.6       26.2
                                      ---------  ---------  ---------  ---------  ---------  ---------  ---------
Combined ratio......................      123.1%     109.9%     105.4%     105.9%     105.6%     105.4%     108.4%
                                      ---------  ---------  ---------  ---------  ---------  ---------  ---------
                                      ---------  ---------  ---------  ---------  ---------  ---------  ---------
</TABLE>
 
- ------------------------------
 
(1) For 1992, income from continuing operations, operating income and GAAP
    ratios have been significantly affected by certain events relating to a
    special assessment by the state of Florida ($2,224), option termination
    expense ($557), a provision for reinsurance ($5,647) and interest income on
    a tax refund ($715).
 
(2) MMI adopted a new standard on accounting for investments in 1994.
 
(3) Income from continuing operations excludes amounts relating to segments that
    were discontinued in 1992. Losses from discontinued operations were $7,024
    in 1992 and $5,100 in 1996. (See Note 14 to the Consolidated Financial
    Statements).
 
(4) Per share data and weighted average shares are presented on a fully diluted
    basis.
 
(5) GAAP ratios have been derived from the financial statements of American
    Continental Insurance Company ("ACIC"), American Continental Life Insurance
    Company ("ACLIC"), and Health Providers Insurance Company ("HPIC"), from the
    date of its acquisition in 1995, as prepared on a GAAP basis for inclusion
    in MMI's consolidated financial statements. The loss ratio is the ratio of
    loss and loss adjustment expenses to net premiums earned. The expense ratio
    is the ratio of insurance segment insurance and administrative expenses to
    net premiums earned. The combined ratio is the sum of the loss ratio and the
    expense ratio. Events described in Note 1 resulted in an increase in the
    GAAP combined ratio of 5.8 percentage points in 1992.
 
(6) MMI entered into business combinations as described in Note 2 to the
    Consolidated Financial Statements and acquired McManis Associates, Inc. in
    December 1993.
 
                                       9
<PAGE>
SELECTED CONSOLIDATED FINANCIAL INFORMATION OF UNIONAMERICA
 
    The following table sets forth selected consolidated financial information
of Unionamerica for each of the years in the five-year period ended December 31,
1996 and for each of the six month periods ended June 30, 1996 and 1997. The
balance sheet data as of December 31, 1993, 1994, 1995 and 1996 and the premium
and income data for the years ending December 31, 1992, 1993, 1994, 1995 and
1996 are derived from the audited consolidated financial statements of
Unionamerica. The selected information as of and for each of the six month
periods ended June 30, 1996 and 1997 and the balance sheet data as of December
31, 1992 has been extracted from the unaudited consolidated financial statements
of Unionamerica. In the opinion of Unionamerica's management, the unaudited
consolidated financial information includes all adjustments necessary for a fair
presentation of the financial position and results of operations for such
periods. The selected consolidated financial information should be read in
conjunction with Unionamerica's consolidated financial statements and notes
thereto incorporated by reference in this Prospectus. Unionamerica's functional
currency has been determined to be the U.S. dollar.
<TABLE>
<CAPTION>
                               PREDECESSOR COMPANY                             SUCCESSOR COMPANY
                           ---------------------------   --------------------------------------------------------------
                                          PERIOD FROM     PERIOD FROM    COMBINED PRO
                                           JANUARY 1,    SEPTEMBER 10,    FORMA YEAR
                            YEAR ENDED      1993 TO         1993 TO         ENDED           YEAR ENDED DECEMBER 31,
                           DECEMBER 31,   SEPTEMBER 9,   DECEMBER 31,    DECEMBER 31,   -------------------------------
                               1992         1993(1)         1993(1)        1993(1)        1994       1995       1996
                           ------------   ------------   -------------   ------------   ---------  ---------  ---------
                                                       (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS AND RATIOS)
<S>                        <C>            <C>            <C>             <C>            <C>        <C>        <C>
PREMIUM AND INCOME DATA:
Gross premiums written...    $130,407       $135,197       $ 10,756        $145,953     $ 140,401  $ 157,366  $ 145,897
Net premiums written.....     114,907        118,254         10,742         128,996       124,584    137,207    122,725
Net premiums earned......     111,805         89,684         36,009         125,693       135,587    117,712    116,982
Net investment income....      25,893         17,154          6,217          23,371        22,083     23,086     29,407
Net realized gains
  (losses) on
  investments(2).........       4,536          4,672            701           5,373       (32,408)       325       (850)
Total revenues...........     143,055        113,845         43,060         156,905       125,262    141,123    145,539
Income (loss) before
  extraordinary
  loss(3)................      14,050         13,964          5,229          19,193        (6,791)    12,953     19,105
Extraordinary loss, net
  of taxes(4)............      --             --             --              --            --         (4,737)    --
Net income (loss)
  available to ordinary
  shareholders...........                                     4,792                        (8,253)     6,699     19,105
Income (loss) per
  ordinary share:
  Income (loss) before
    extraordinary loss...                                      1.00                         (1.85)      2.28       2.18
  Extraordinary loss.....                                    --                            --          (0.94)    --
  Net income (loss)
    available to ordinary
    shareholders.........                                      1.00                         (1.85)      1.34       2.18
Dividend per ordinary
  share(5)                                                   --                            --         0.0125     0.0500
Weighted average number
  of shares and share
  equivalents............                                     4,792          --             4,464      5,018      8,754
BALANCE SHEET DATA (AT
  END OF PERIOD):
Cash and
  investments(6)(7)......    $361,417                      $380,394                     $ 350,872  $ 422,764  $ 425,293
Total assets(7)..........     498,772                       793,977                       712,607    765,118    750,790
Loss and loss adjustment
  expense reserves(7)....     330,480                       603,743                       559,263    561,055    524,153
Long-term debt...........      --                            76,000                        69,000     40,000     35,000
Redeemable preference
  shares.................      --                            15,437                        16,899     --         --
Net unrealized gains
  (losses) on
  investments............      --                            (3,442)                       (2,233)     4,219        665
Stockholders' equity.....      93,357                        20,932                        13,893     85,803    103,200
Book value per share.....      --                            --                              3.11      10.35      12.23
GAAP RATIOS:
Loss ratio...............        76.8%          76.9%          61.4%           72.5%         64.7%      64.8%      62.4%
Expense ratio............        32.8           26.7           31.2            28.0          31.4       33.8       36.9
                           ------------   ------------   -------------   ------------   ---------  ---------  ---------
Combined ratio...........       109.6%         103.6%          92.6%          100.5%         96.1%      98.6%      99.3%
                           ------------   ------------   -------------   ------------   ---------  ---------  ---------
                           ------------   ------------   -------------   ------------   ---------  ---------  ---------
 
<CAPTION>
                             SIX MONTHS ENDED
                                 JUNE 30,
                           --------------------
                             1996       1997
                           ---------  ---------
<S>                        <C>        <C>
PREMIUM AND INCOME DATA:
Gross premiums written...  $ 107,858  $ 115,892
Net premiums written.....     91,614     96,519
Net premiums earned......     67,230     64,448
Net investment income....     13,863     13,692
Net realized gains
  (losses) on
  investments(2).........        186       (660)
Total revenues...........     81,279     77,480
Income (loss) before
  extraordinary
  loss(3)................      9,562      8,187
Extraordinary loss, net
  of taxes(4)............     --           (267)
Net income (loss)
  available to ordinary
  shareholders...........      9,562      7,920
Income (loss) per
  ordinary share:
  Income (loss) before
    extraordinary loss...       1.10       0.93
  Extraordinary loss.....     --          (0.03)
  Net income (loss)
    available to ordinary
    shareholders.........       1.10       0.90
Dividend per ordinary
  share(5)                     0.025      0.025
Weighted average number
  of shares and share
  equivalents............      8,725      8,838
BALANCE SHEET DATA (AT
  END OF PERIOD):
Cash and
  investments(6)(7)......  $ 419,114  $ 417,850
Total assets(7)..........    795,412    782,981
Loss and loss adjustment
  expense reserves(7)....    558,103    512,296
Long-term debt...........     37,500     35,000
Redeemable preference
  shares.................     --         --
Net unrealized gains
  (losses) on
  investments............     (3,988)       348
Stockholders' equity.....     89,215    110,882
Book value per share.....      10.57      13.14
GAAP RATIOS:
Loss ratio...............       64.1%      61.1%
Expense ratio............       34.0       37.9
                           ---------  ---------
Combined ratio...........       98.1%      99.0%
                           ---------  ---------
                           ---------  ---------
</TABLE>
 
                         (Footnotes on following page)
 
                                       10
<PAGE>
(1) Unionamerica acquired Unionamerica Insurance Company Limited from
    Continental Corporation on September 10, 1993 (the "UA Acquisition"). In
    this financial presentation, the statement of operations data for 1993 has
    been split into the pre-UA Acquisition period from January 1, 1993 to
    September 9, 1993 and the post-UA Acquisition period from September 10, 1993
    to December 31, 1993. For convenience, these results have been combined on a
    pro forma basis under the caption "Combined Pro Forma Year Ended December
    31, 1993".
 
(2) In order to eliminate the ongoing effects on Unionamerica's results of
    operations of the amortization of UA Acquisition-related purchase premium on
    debt securities, Unionamerica sold substantially all of its debt securities
    in 1994. As a result of such sales, Unionamerica realized the remaining
    amount of such purchase premium $(28.2 million) as a realized loss during
    the year.
 
(3) Net income (loss) for the post-UA Acquisition period does not reflect issued
    or accrued dividends on Senior Preference Shares in issue from 1993 to 1995.
 
(4) The extraordinary loss in 1995 is in respect of the write-off of deferred
    financing costs in the amount of $3.3 million pre-tax ($2.2 million
    after-tax) upon the refinancing of Unionamerica's prior long term debt
    together with a premium on early redemption of its subordinated loan notes
    in the amount of $2.5 million pre-tax ($2.5 million after tax). The
    extraordinary loss in 1997 is in respect of the write-off of deferred
    financing costs, net of tax, of $0.3 million upon the refinancing of
    long-term debt.
 
(5) Unionamerica declared its first dividend, a quarterly dividend, of $0.0125
    per share of Unionamerica Common Stock on January 31, 1996 and has declared
    quarterly dividends of $0.0125 per share of Unionamerica Common Stock each
    quarter since that date.
 
(6) During 1995 Unionamerica received $63.1 million related to a commutation
    with Accord Re.
 
(7) At December 31, 1993, and all subsequent reporting dates, both assets and
    outstanding losses and loss adjustment expenses and unearned premiums were
    grossed-up separately to account for reinsurance recoverables in accordance
    with Statement of Financial Accounting Standards No. 113. Prior periods have
    not been similarly presented.
 
                                       11
<PAGE>
SELECTED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION
 
    The selected pro forma condensed combined financial information for each of
the years in the three year period ended December 31, 1996 and as of June 30,
1997 and for each of the six month periods ended June 30, 1996 and 1997 is
derived from the unaudited pro forma condensed combined financial information
included elsewhere in this Prospectus. See "Unaudited Pro Forma Condensed
Combined Financial Information". The pro forma condensed combined financial
information does not purport to represent what the combined financial position
or results of operations actually would have been if the Proposed Acquisition
had been completed at the beginning of the periods presented. The information
presented below should be read in conjunction with the historical financial
statements of MMI and Unionamerica incorporated by reference and the unaudited
pro forma condensed combined financial statements included elsewhere in this
Prospectus.
 
<TABLE>
<CAPTION>
                                                                                            SIX MONTHS ENDED
                                                     YEAR ENDED DECEMBER 31,                    JUNE 30,
                                             ----------------------------------------  --------------------------
                                                 1994          1995          1996          1996          1997
                                             ------------  ------------  ------------  ------------  ------------
                                                     (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS AND RATIOS)
<S>                                          <C>           <C>           <C>           <C>           <C>
PREMIUMS AND INCOME DATA:
Gross premiums written.....................  $    323,070  $    365,747  $    357,718  $    237,416  $    244,919
Net premiums written.......................       264,384       298,395       290,117       191,839       196,479
Net premiums earned........................       267,976       272,903       281,391       149,054       142,759
Consulting and fee income..................        18,602        22,336        34,535        15,628        25,308
Net investment income......................        51,150        62,936        73,681        35,516        36,980
Total revenues.............................       302,467       359,867       388,717       201,386       206,017
Income from continuing operations before
  extraordinary loss.......................         8,260        35,648        45,220        23,321        21,707
  Per share................................          0.54          2.46          2.50          1.33          1.12
Dividends per common share outstanding at
  end of period............................          0.16          0.20          0.24          0.12          0.14
Weighted average number of common and
  common equivalent shares.................        12,495        13,878        18,088        17,570        19,396
 
BALANCE SHEET DATA (AT END OF PERIOD):
Cash and investments.......................                                                          $  1,183,949
Total assets...............................                                                             1,864,630
Loss and loss adjustment expense
  reserves.................................                                                             1,138,655
Long-term debt.............................                                                                93,000
Net unrealized gains on investments........                                                                12,149
Stockholders' equity.......................                                                               374,081
Book value per share.......................                                                                 19.99
 
GAAP RATIOS:
Loss ratio.................................          74.8%         75.6%         74.2%         74.4%         72.7%
Expense ratio..............................          25.9          27.2          28.8          27.4          31.5
                                             ------------  ------------  ------------  ------------  ------------
Combined ratio.............................         100.7%        102.8%        103.0%        101.8%        104.2%
                                             ------------  ------------  ------------  ------------  ------------
                                             ------------  ------------  ------------  ------------  ------------
</TABLE>
 
SEE NOTES TO SELECTED CONSOLIDATED FINANCIAL INFORMATION ON PAGES 9 THROUGH 11.
 
                                       12
<PAGE>
COMPARATIVE HISTORICAL AND PRO FORMA PER SHARE DATA
 
    The following table sets forth MMI's and Unionamerica's historical per share
data and pro forma combined per share data for the years ended December 31,
1994, 1995 and 1996 and for the six months ended June 30, 1996 and 1997 giving
effect to the Proposed Acquisition, to be accounted for as a pooling-
of-interests, and is derived from the historical financial statements of MMI and
Unionamerica and the unaudited pro forma condensed combined financial
information. The pro forma combined financial information does not purport to
represent what the combined financial position or results of operations actually
would have been if the Proposed Acquisition had been completed at the beginning
of the periods presented. The information presented below should be read in
conjunction with the historical financial statements of MMI and Unionamerica
incorporated by reference and the unaudited pro forma condensed combined
financial statements included elsewhere in this Prospectus. See "Unaudited Pro
Forma Condensed Combined Financial Information".
 
<TABLE>
<CAPTION>
                                                                                                      SIX MONTHS ENDED
                                                                       YEAR ENDED DECEMBER 31,            JUNE 30,
                                                                   -------------------------------  --------------------
                                                                     1994       1995       1996       1996       1997
                                                                   ---------  ---------  ---------  ---------  ---------
<S>                                                                <C>        <C>        <C>        <C>        <C>
MMI
  Book value (at end of period)..................................                        $   21.67             $   22.59
  Cash dividends.................................................  $    0.16  $    0.20       0.24  $    0.12       0.14
  Income from continuing operations..............................       1.72       2.34       2.42       1.34       1.13
 
UNIONAMERICA
  Book value (at end of period)..................................                            12.23                 13.14
  Cash dividends.................................................     --         0.0125      0.050      0.025      0.025
  Income (loss) before extraordinary loss........................      (1.85)      2.28       2.18       1.10       0.93
  Income (loss) from continuing operations(1)....................      (1.85)      1.34       2.18       1.10       0.90
 
UNIONAMERICA PRO FORMA(2)
  Book value (at end of period)..................................                            15.89                 16.71
  Cash dividends(3)..............................................       0.13       0.17       0.20       0.10       0.12
  Income (loss) before extraordinary loss........................       0.45       2.06       2.09       1.11       0.94
  Income (loss) from continuing operations(1)....................       0.45       1.77       2.09       1.11       0.93
 
MMI PRO FORMA COMBINED
  Book value (at end of period)..................................                            19.01                 19.99
  Cash dividends(3)..............................................       0.16       0.20       0.24       0.12       0.14
  Income before extraordinary loss...............................       0.54       2.46       2.50       1.33       1.12
  Income from continuing operations(1)...........................       0.54       2.12       2.50       1.33       1.11
</TABLE>
 
- ------------------------
 
 (1) Unionamerica recorded an extraordinary loss, net of taxes, of $4.7 million
     in 1995 related to a write-off of deferred financing costs and a premium on
     early redemption of subordinated loan notes, and $0.3 million in 1997
     related to a write-off of deferred financing costs upon the refinancing of
     long-term debt.
 
 (2) Gives effect to the Exchange Ratio of 0.836 shares of MMI Common Stock per
     Unionamerica ADS.
 
 (3) Gives effect to the dividend rate on MMI Common Stock.
 
MARKET PRICE OF MMI COMMON STOCK AND UNIONAMERICA ADSS
 
    On June 25, 1997 MMI announced the signing of the Acquisition Agreement and
its intent to make the Offer. The following table sets forth the closing price
of MMI Common Stock and Unionamerica ADSs on the NYSE on June 24, 1997 (being
the last trading day prior to the announcement that Unionamerica and MMI had
entered into the Acquisition Agreement), and for October 31, 1997 (being
 
                                       13
<PAGE>
the latest practicable date prior to the filing of this Prospectus with the
Commission), and the equivalent market price for the amount of MMI Common Stock
being offered per Unionamerica ADS, based on the Exchange Ratio of 0.836 shares
of MMI Common Stock per Unionamerica ADS.
 
<TABLE>
<CAPTION>
                                        CLOSING      EQUIVALENT
                                         PRICE      MARKET PRICE
                                      -----------  ---------------
<S>                                   <C>          <C>
June 24, 1997:
MMI Common Stock....................   $   26.50         --
Unionamerica ADSs...................       19.50      $   22.15
 
October 31, 1997:
MMI Common Stock....................   $   24.94             --
Unionamerica ADSs...................   $   19.88      $   20.85
</TABLE>
 
    The amounts set forth in the above table for June 24, 1997 represent an
increase in value of Unionamerica ADSs (assuming the exchange was completed on
such date) of $2.65 or 13.59% (without accounting for any liability for taxes or
for sales expenses associated with a transfer of Unionamerica ADSs, and assuming
the issuance of fractional shares).
 
MMI COMMON STOCK AND UNIONAMERICA ADSS HELD BY DIRECTORS, EXECUTIVE OFFICERS AND
  THEIR AFFILIATES
 
    MMI.  As of June 30, 1997, 16 directors and executive officers of MMI as a
group reported beneficial ownership, directly and indirectly, of 366,000 shares
of MMI Common Stock and 571,000 options, exercisable within 60 days, to purchase
shares of MMI Common Stock. The number of shares of MMI Common Stock and options
beneficially held by directors and executive officers, totalling 937,000,
represents 7.6% of the total of the number of shares of MMI Common Stock
outstanding as of June 30, 1997 plus the options held by the directors and
executive officers of MMI.
 
    As reported in a Schedule 13G filed with the Commission and dated May 5,
1997, Wellington Management Company, LLP ("Wellington") reported beneficial
ownership of 1,185,940 shares of MMI Common Stock, representing 10.10% of the
issued share capital of MMI. With respect to those shares, Wellington had the
sole power to vote 615,440 shares and the sole power to direct the disposition
of 1,185,940 shares.
 
    UNIONAMERICA.  The existing shareholders of Unionamerica as of December 4,
1995, including 15 directors and officers of Unionamerica, are parties to an
amended Shareholders' Agreement (the "Shareholders' Agreement") which contains
certain restrictions on the transfer of Unionamerica Common Stock by certain of
the parties thereto, as well as certain voting agreement provisions. As a result
of the Shareholders' Agreement, the parties thereto may be deemed to constitute
a group within the meaning of Rule 13d-5 under the Exchange Act. As such, the
group has reported that it may be deemed to own beneficially an aggregate of
4,867,778 Unionamerica ADSs, representing 55% of the Unionamerica ADSs
outstanding as of December 31, 1996. One of the parties to the Shareholders'
Agreement, UA Partners, L.P., reported beneficial ownership of 1,147,355
Unionamerica ADSs, representing 12.99% of the issued and outstanding
Unionamerica ADSs as of December 31, 1996. With the application of the
Unionamerica Articles' voting provisions, the Unionamerica ADSs owned by UA
Partners, L.P. represents 4.20% of the voting Unionamerica Securities.
 
    MMI has not entered into any employment agreements with any members of the
management of Unionamerica that would require MMI to make payments to those
people as a result of the Proposed Acquisition.
 
                                       14
<PAGE>
    As of October 31, 1997 the number of Unionamerica ADSs and options
beneficially held by directors and officers, totalling 1,075,126, represents
11.7% of the total number of Unionamerica ADSs outstanding as of October 31,
1997 plus the options held by the directors and officers of Unionamerica.
 
    As reported in a Schedule 13G filed with the Commission and dated March 10,
1997, FMR Corp. reported beneficial ownership of 1,077,600 Unionamerica ADSs
which represented 12.77% of the issued and outstanding Unionamerica ADSs as of
December 31, 1996. With the application of the Unionamerica Articles' voting
provisions, the Unionamerica ADSs beneficially owned by FMR Corp. represent
15.04% of the voting Unionamerica Securities. The power to vote the 1,077,600
Unionamerica ADSs is held by the Board of Trustees of various FMR Corp.
investment companies.
 
REGULATORY APPROVAL REQUIREMENTS
 
    In accordance with certain U.K. and U.S. antitrust laws, various regulatory
approvals are required to be obtained under the Offer: (i) on September 12,
1997, the U.K. Department of Trade and Industry advised MMI that it had no
objection to MMI becoming a controller (as defined in the Insurance Companies
Act 1982) of a Subsidiary of Unionamerica, Unionamerica Insurance Company
Limited; (ii) on September 19, 1997, Lloyd's advised MMI that it had no
objection to the proposed new controllers of Unionamerica becoming controllers
of Jago Capital Limited and on October 29, 1997, Lloyd's advised MMI that it had
no objection to MMI becoming a controller of Jago Managing Agency Limited, a
Lloyd's managing agency in which Unionamerica has an effective equity interest
of approximately 39%; and (iii) on September 15, 1997 the Federal Trade
Commission granted the request of MMI for early termination of the waiting
period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as
amended, and the rules and regulations thereunder (the "HSR Act"). In addition,
the Offer will lapse if it is referred to the Monopolies and Mergers Commission
of the U.K. (the "MMC") before 12 midnight, New York time, on the Expiration
Date, including any extension thereof, or the date on which the Offer becomes or
is declared unconditional in all respects, whichever is the later.
 
    For a complete discussion of the regulatory approvals necessary to
consummate the Offer and the Proposed Acquisition, see "The Offer--Terms of the
Offer and Proposed Acquisition--Conditions of the Offer" and Appendix
E--"Certain Additional Information Required Under the City Code--Certain Legal
and Regulatory Matters". MMI is unable to predict the amount of time necessary
to obtain the governmental and regulatory approvals and consents required to
consummate the Offer and the Proposed Acquisition contemplated herein. It is
anticipated, however, that in the event the time necessary to obtain such
governmental and regulatory approvals and consents extends beyond the Expiration
Date, MMI will extend the Expiration Date pursuant to the terms of the
Acquisition Agreement.
 
DISSENTERS' RIGHTS
 
    UNIONAMERICA.  Under English law, shareholders do not generally have
dissenters' rights, as the concept is understood under the General Corporation
Law of the State of Delaware, as amended from time to time (the "DGCL"), and the
Unionamerica Articles do not contain any dissenters' rights. Certain limited
rights analogous to dissenters' rights exist where an offeror who, pursuant to a
takeover offer for a company, has acquired or contracted to acquire not less
than nine-tenths in value of the shares to which the offer relates, seeks to
acquire the outstanding minority shareholdings pursuant to the compulsory
acquisition provisions under the Companies Act. See "The Offer--Changes in the
Rights of Unionamerica Securityholders--Required Vote for Authorization of
Certain Corporate Actions and Certain Provisions Relating to Business
Combinations" and Appendix F--"Certain Provisions of the Companies Act".
 
    MMI.  Under the DGCL, holders of MMI Common Stock are not entitled to
dissenters' rights in connection with the Offer and the Proposed Acquisition.
 
                                       15
<PAGE>
TAX CONSEQUENCES OF THE OFFER
 
    Exchanges of Unionamerica ADSs for MMI Common Stock pursuant to the Offer
and the Proposed Acquisition will be treated for U.S. federal income tax
purposes as exchanges pursuant to a transaction described in Section
368(a)(1)(B) of the IRC, and no gain or loss will be recognized by (i) MMI or
Unionamerica as a result of the Offer or the Proposed Acquisition or (ii) a
holder of Unionamerica ADSs upon the exchange pursuant to the Offer or the
Proposed Acquisition of such Unionamerica ADSs solely for MMI Common Stock,
except with respect to the receipt of cash in lieu of fractional shares of MMI
Common Stock. It is a Condition of the closing of the Offer that Paul, Weiss,
Rifkind, Wharton & Garrison, special U.S. tax counsel to Unionamerica, provide
an opinion to the foregoing effect.
 
    All Unionamerica Securityholders should carefully read the summary of the
material income tax consequences of the Offer and the Proposed Acquisition under
"The Offer--Tax Consequences of the Offer" and are urged to consult with their
own tax advisors as to the U.S., U.K., state and local tax consequences in their
particular circumstances.
 
                                       16
<PAGE>
                                  RISK FACTORS
 
    Unionamerica Securityholders should carefully consider the following
matters, together with the other information contained in this Prospectus, in
evaluating the Offer.
 
    FIXED EXCHANGE RATIO; CHANGE IN RELATIVE STOCK PRICES MAY CHANGE VALUE OF
CONSIDERATION RECEIVED. The Exchange Ratio is expressed in the Acquisition
Agreement as a fixed ratio of 0.836 shares of MMI Common Stock for each
Unionamerica ADS. Accordingly, the Exchange Ratio will not be adjusted in the
event of any increase or decrease in the price of either MMI Common Stock or
Unionamerica ADSs. Therefore, the value of the consideration received by
Unionamerica Securityholders may change. The price of MMI Common Stock at the
closing of the Proposed Acquisition is likely to vary from its price at the date
of this Prospectus and at the date of the MMI Special Meeting. Such variations
may be the result of changes in the business, operations or prospects of MMI or
Unionamerica, market assessments of the likelihood that the Proposed Acquisition
will be consummated and the timing thereof, regulatory considerations, general
market and economic conditions and other factors. Unionamerica Securityholders
are urged to obtain current market quotations for MMI Common Stock and
Unionamerica ADSs.
 
    FAILURE TO QUALIFY FOR POOLING-OF-INTERESTS ACCOUNTING TREATMENT MAY IMPACT
REPORTED OPERATING RESULTS. The Offer and the Proposed Acquisition are intended
to qualify for pooling-of-interests treatment under GAAP. Under
pooling-of-interests treatment, the accounts of MMI will be combined with those
of Unionamerica at their historical carrying amount and MMI's financial
statements for all prior periods will be restated to reflect the accounts of MMI
as if the two companies had been combined for all periods.
 
    Should the Proposed Acquisition become or be declared unconditional in all
respects and not qualify for pooling-of-interests treatment, the purchase method
of accounting would be applied. Under that method, the estimated fair value of
the MMI Common Stock issued to effect the Proposed Acquisition would be recorded
as the cost of acquiring Unionamerica's business. That cost would be allocated
to the individual assets acquired and liabilities assumed according to their
respective fair values with the excess of the estimated fair value of MMI Common
Stock over the fair value of net assets acquired recorded as goodwill, to be
amortized over a period up to 40 years. The estimated fair value of the MMI
Common Stock to be issued pursuant to the Proposed Acquisition is substantially
in excess of the amount at which the net assets are carried in Unionamerica's
accounts. Accordingly, purchase accounting treatment may have a material adverse
impact on the reported operating results of the combined companies as compared
to that under pooling-of-interests treatment. See "The Offer--Terms of the Offer
and Proposed Acquisition", and "Accounting Treatment".
 
    FUTURE SALES OF SOME MMI COMMON STOCK ISSUED PURSUANT TO THE OFFER AND
COMPULSORY ACQUISITION WILL BE RESTRICTED.  Assuming the Offer and the
Compulsory Acquisition are successfully completed, up to 7,685,336 shares of MMI
Common Stock will be issued, of which up to 5,995,999 shares will be immediately
freely tradeable under the Securities Act. The remaining 1,689,337 shares, which
will be issued to affiliates of Unionamerica, will be freely tradeable after MMI
has published financial results covering at least 30 days of combined
operations. Sales of a substantial number of such shares of MMI Common Stock
could adversely affect the market price of the MMI Common Stock. See "The
Offer-- Terms of the Offer and Proposed Acquisition".
 
    CHANGES IN THE RIGHTS OF UNIONAMERICA SECURITYHOLDERS WILL
OCCUR.  Unionamerica is incorporated under English law. Those Unionamerica
Securityholders who exchange their Unionamerica ADSs for MMI Common Stock and
whose rights as Unionamerica Securityholders are currently governed by English
law, including the Companies Act, and by the Unionamerica Articles, will, upon
the exchange of Unionamerica ADSs, become stockholders of MMI and their rights
as stockholders will be governed by the laws of the U.S., and by the DGCL, the
Restated Certificate of Incorporation of MMI (the "MMI Certificate"), and the
Amended and Restated Bylaws of MMI (the "MMI Bylaws"). MMI and Unionamerica are
both currently subject to the U.S. securities laws and the rules and regulations
of the NYSE.
 
                                       17
<PAGE>
Certain differences between the rights of Unionamerica Securityholders and the
stockholders of MMI arise from differences between English law and the laws of
the U.S. and the DGCL, as well as from differences between the corporate
governing instruments of the two companies, and the rules and regulations of the
regulatory bodies governing the two companies. These differences may have a
material effect on the rights of Unionamerica Securityholders to nominate, vote
for and remove directors, approve certain corporate action, receive dividends,
and inspect corporate records, among other things. See "The Offer--Description
of MMI Capital Stock", "The Offer--Description of Unionamerica Capital Stock"
and "The Offer--Changes in the Rights of Unionamerica Securityholders".
 
    REALIZATION OF EXPECTED OPERATING SYNERGIES MAY NOT MATERIALIZE.  The
Proposed Acquisition involves the combination of two companies that have
previously operated independently of each other. Although MMI expects to achieve
savings in operating costs, delays or unexpected expenses related to operating
the companies under common ownership could result in reductions in net income.
In addition, it is possible that MMI or Unionamerica may experience the loss of
personnel or customers as a result of the Proposed Acquisition.
 
    INDUSTRY FACTORS AND COMPETITION MAY INFLUENCE FUTURE RESULTS.  Many factors
influence the financial results of the medical malpractice insurance and
reinsurance businesses, several of which are beyond the control of MMI. The
supply of insurance, or the industry's underwriting capacity, is determined
principally by the industry's level of capitalization, historical underwriting
results, returns on investment and perceived premium rate adequacy. MMI and
Unionamerica compete with numerous insurance companies and consulting
businesses, many of which have greater financial resources than do MMI and
Unionamerica. These factors, together with competitive pricing, could result in
fluctuations in underwriting results and net income.
 
    UNDERWRITING LOSSES AND RESERVES ARE BASED ON ESTIMATES.  The reserves for
losses and loss adjustment expenses established by MMI and by Unionamerica are
estimates of amounts needed to pay reported and unreported claims and related
loss adjustment expenses. The estimates are based on assumptions related to the
ultimate cost of settling such claims. If the reserves are inadequate, MMI will
be required to increase its reserves and thus reduce its net income in the
period in which the deficiency is identified. Unanticipated underwriting losses
or materially underestimated reserves could have a material adverse effect on
MMI.
 
    ABILITY OF REINSURERS TO PAY CLAIMS.  In order to reduce risk and to
increase its underwriting capacity, MMI and Unionamerica obtain reinsurance from
unaffiliated reinsurers, although they generally retain a portion of each risk
reinsured. MMI and Unionamerica are subject to credit risk with respect to their
reinsurers because reinsurance does not relieve the ceding company of liability
to its insureds for the risks ceded to reinsurers. Although MMI believes that
its and Unionamerica's reinsurance is maintained with financially stable
reinsurers and that any reinsurance security maintained is adequate to protect
their interests, a reinsurer's insolvency or inability to make payments under
the terms of a reinsurance treaty could have a material adverse effect on MMI.
 
    HOLDING COMPANY STRUCTURE AND RESTRICTIONS ON INSURANCE SUBSIDIARIES.  As a
holding company, MMI depends on dividends and other permitted payments from its
Subsidiaries to meet its cash needs, including servicing its debt and paying
stockholder dividends. The Missouri and Illinois insurance laws and regulations
impose restrictions on the amount of dividends that may be paid to stockholders
by insurance companies domiciled in the respective states without prior approval
of the Director of Insurance in such states. ACIC may not, without the prior
approval of the Missouri Director of Insurance, pay a dividend that, together
with any other dividends paid within the twelve-month period ending on the date
when the dividend will be paid, exceeds the lesser of ACIC's net investment
income for the prior calendar year or ten percent of its statutory surplus as of
December 31 of the prior calendar year. HPIC may not, without the prior approval
of the Illinois Director of Insurance, pay a dividend that, together with any
other dividends paid within the twelve-month period ending on the date when the
dividend will be paid, exceeds
 
                                       18
<PAGE>
the greater of ten percent of its statutory surplus as of December 31 of the
prior calendar year or net income for the prior calendar year.
 
    In connection with Unionamerica's authorization in the U.K., the Secretary
of State for Trade and Industry acting through the Insurance Directorate of the
U.K. Department of Trade and Industry ("DTI") has set forth Unionamerica's
Notice of Requirements, the provisions of which include, among other things,
that Unionamerica may not pay any dividends unless it has given the DTI 14 days
advance notice and the DTI has not objected. The DTI has the power to prohibit
or require Unionamerica to reduce the amount of a dividend, restrict the amount
of its writings and to prohibit transactions by Unionamerica with affiliates.
 
    MMI's bank credit agreement restricts dividends and share repurchases in an
amount not to exceed for each fiscal year 20% of MMI's consolidated net earnings
after taxes of the previous fiscal year, but MMI may in one fiscal year during
the term of the bank credit agreement pay an amount of dividends up to the
amount paid in the prior fiscal year without regard to the amount of its
consolidated net earnings after taxes in such prior fiscal year. Unionamerica's
bank credit agreement contains covenants, including among others, limitations on
dividend payments, minimum statutory capital and surplus requirements and fixed
charge ratios.
 
    REGULATION.  Unionamerica and its Subsidiaries, and MMI's insurance
Subsidiaries, are subject to supervision and regulation of their businesses and
financial condition by the jurisdictions in which they transact business. The
primary purpose of such supervision and regulation is the protection of the
interests of policyholders as opposed to the interests of the holders of MMI
Common Stock and Unionamerica ADSs. Such supervision and regulation generally
derives from statutes which delegate broad regulatory, supervisory and
administrative authority to insurance departments and other governmental
entities.
 
    In addition to state-imposed insurance laws and regulations, MMI is subject
to statutory accounting practices and the reporting format of the National
Association of Insurance Commissioners (the "NAIC"). The NAIC and many states
have adopted risk-based capital formulas to establish minimum capital and
surplus requirements for insurance companies and a model act for regulation of
such companies. The risk based capital formula measures a company's asset risk,
insurance risk, interest rate risk and business risk. As of December 31, 1996,
the surplus of each of MMI's insurance Subsidiaries exceeded the minimum
requirements under the NAIC formula.
 
    The impact on MMI of any changes in these laws, or of changes in or the
adoption of any other laws or regulations, cannot be predicted.
 
    Unionamerica is a U.K. authorized insurance company subject to regulation
and supervision in the U.K. under U.K. domestic and European Community law. The
Insurance Companies Act 1982, as amended, imposes on U.K. insurance companies
solvency and liquidity standards and auditing and reporting requirements, and
further grants to the DTI powers to supervise, investigate and intervene in the
affairs of insurance companies. Unionamerica is subject to a Notice of
Requirements issued by the DTI (as is frequently the DTI's practice in
connection with an acquisition of a U.K. insurance company) which, among other
things, restricts Unionamerica from entering into certain transactions with
affiliates and sets a ceiling on the annual amount of gross premiums that may be
written by Unionamerica. In addition, before it may pay any dividend,
Unionamerica is required to give 14 days' advance notice to the DTI, which has
the ability to reduce or prohibit such payment. Unionamerica is permitted to
seek the approval of the DTI for an increase in the gross premiums ceiling in
respect of one or more years and may do so depending on future business
conditions. Neither Unionamerica nor any of its Subsidiaries is incorporated or
licensed as an insurance company in any jurisdiction of the U.S. Each state of
the U.S. regulates to an extent the purchase of insurance and reinsurance by its
citizens from alien insurers and reinsurers, such as Unionamerica. Recently,
insurance regulation in the U.S., particularly as it relates to alien insurers
and reinsurers, has been subject to increased scrutiny by the NAIC and
legislative and regulatory bodies.
 
                                       19
<PAGE>
    Medical malpractice and hospital professional indemnity coverages written
for U.S. reinsureds and insureds constituted 28% of Unionamerica's gross
premiums written in 1996. Changes in U.S. laws relating to medical malpractice
liability have been proposed from time to time in recent years. The impact on
MMI and Unionamerica of such changes in these laws, if adopted, or of changes in
or the adoption of any other laws or regulations, cannot be predicted.
 
    TAXATION.  The combined entity's operations will be subject to taxation in
jurisdictions outside the U.S. Specifically, as a result of the Proposed
Acquisition, certain of MMI's operations will be subject to both U.S. taxation
and U.K. taxation, and may be subject to taxation in other jurisdictions. The
U.S. taxation system provides credit for federal taxes paid to other
jurisdictions, subject to certain limitations. If such limitations on available
credits apply, and excess foreign tax credits exist, the effective tax rate
relating to the foreign operations of MMI in any one taxable period could exceed
the U.S. federal statutory rate. MMI's management intends to implement planning
such that foreign tax credits are fully utilized.
 
    In addition, the tax laws of the U.S. and the U.K. could change which may
result in additional taxes.
 
    FAILURE TO QUALIFY FOR U.S. TAX FREE REORGANIZATION TREATMENT.  The Internal
Revenue Service (the "IRS") may challenge the tax free nature of the
reorganization. If such a challenge by the IRS were to prevail, holders of
Unionamerica ADSs who receive MMI Common Stock in the Proposed Acquisition will
recognize a gain or loss for United States federal income tax purposes.
 
                                       20
<PAGE>
                                   THE OFFER
 
BACKGROUND OF THE PROPOSED ACQUISITION
 
    Following the receipt of several informal inquiries from third parties
regarding Unionamerica's interest in exploring a business combination, the
Unionamerica Board, at a meeting on January 29, 1997, discussed the company's
strategy on mergers and acquisitions and agreed that Donaldson, Lufkin &
Jenrette Securities Corporation ("DLJ") would act as Unionamerica's exclusive
financial advisor and act as intermediary in any negotiations with interested
parties.
 
    Following the engagement of DLJ, Unionamerica, through and along with DLJ,
considered the informal inquiries it had received. Unionamerica had preliminary
discussions with certain of the parties that had made such inquiries and with
certain other parties, including MMI, which were selected because, in the
opinion of DLJ and the management of Unionamerica, such companies would fit
strategically with Unionamerica. In all cases other than that of MMI and two
other parties, the discussions were terminated by Unionamerica or the other
party to the discussions before any substantial amount of confidential
information was exchanged. Preliminary proposals from the other two parties were
informally discussed; however, discussions with such parties terminated at a
preliminary stage. As described below, discussions with MMI continued thereafter
and ultimately resulted in a definitive proposal and the negotiation of the
Acquisition Agreement.
 
    Prior to entering into the Acquisition Agreement, the Unionamerica Board
determined that Unionamerica would benefit from being associated with a larger
organization with greater access to, and reduced expense for obtaining, capital.
The Unionamerica Board also determined that Unionamerica Securityholders would
benefit from holding stock in a public company with greater market
capitalization than Unionamerica because such securities would likely have
greater liquidity. The Proposed Acquisition addresses these concerns of the
Unionamerica Board. See "--Unionamerica's Reasons for the Proposed Acquisition
and Recommendation of the Unionamerica Board".
 
    In early 1997, Mr. B. Frederick Becker, Chairman, Chief Executive Officer
and Director of MMI, was made aware of the possibility that Unionamerica might
be receptive to a business combination and decided to investigate and develop a
possible proposal for an acquisition. MMI and Unionamerica have had an ongoing
business relationship in that Unionamerica has been one of MMI's reinsurers for
several years. See "The Offer--Material Contracts Between MMI and Unionamerica."
 
    On February 26, 1997, at a meeting of the Executive and Finance Committee of
the MMI Board (the "Committee"), Mr. Becker, a member of the Committee,
discussed with the Committee analyses relating to a potential acquisition of
Unionamerica, including a description of Unionamerica's business and a summary
financial analysis.
 
    At a meeting on March 11, 1997, Philip M. Marcell, then Chairman and Chief
Executive Officer of Unionamerica, apprised the Unionamerica Board of an
expression of interest by MMI in a potential business combination with
Unionamerica.
 
    On March 14, 1997, MMI and Unionamerica entered into a Confidentiality
Agreement. At that time, MMI began its due diligence investigation of
Unionamerica.
 
    On April 8, 1997, Mr. Becker and Mr. Paul M. Orzech, Executive Vice
President and Chief Financial Officer of MMI, along with representatives of
Smith Barney, met with Mr. Ian Sinclair, CEO of Unionamerica Insurance Company
Limited, Unionamerica's principal operating subsidiary, and Mr. Peter J. Cooper,
Chief Financial Officer of Unionamerica, along with representatives of DLJ, to
discuss the business of Unionamerica, including the history of Unionamerica,
underwriting and reinsurance, reserve adequacy, historical financial results,
investments and business plans.
 
    On April 15, 1997, Mr. Becker and Mr. Orzech, along with representatives of
Smith Barney, met with Mr. Robert Spass, a director of Unionamerica. Topics
discussed included MMI's business reasons for
 
                                       21
<PAGE>
considering a transaction (see--"MMI's Reasons for the Proposed Acquisition and
Recommendation of the MMI Board"), the composition of Unionamerica's shareholder
base and the financial objectives of MMI and Unionamerica (including MMI's
requirement for a transaction which would be non-dilutive to earnings and one
which maintained MMI's debt and insurance claims paying ratings). Issues
relating to the timing of due diligence and negotiations were also discussed.
 
    On April 16, 1997, Mr. Orzech discussed the potential acquisition of
Unionamerica at a meeting of the Committee. Mr. Orzech updated the Committee on
management's activities to date with respect to the transaction, reviewed
Unionamerica's business and organization, and presented various financial data.
The Committee discussed a transaction which would offer as merger consideration
both cash and capital stock of MMI. After this discussion, the Committee granted
MMI management the authority to proceed, within certain parameters, to pursue
the acquisition of Unionamerica. Parameters discussed included a pooling-
of-interests transaction with an exchange ratio of 0.8 or a purchase transaction
with comparable total value, and including up to 25% cash.
 
    Later that same day, Mr. Orzech discussed the potential acquisition of
Unionamerica at a meeting of the MMI Board. Again, Mr. Orzech reviewed
management's activities to date, Unionamerica's business and organization, and
presented various financial data. Mr. Becker then discussed the rationale behind
the acquisition and reported that management would bring final terms and a
recommendation back to the MMI Board. The MMI Board passed a resolution giving
management authority to proceed with the negotiation of definitive agreements
for the acquisition of Unionamerica, provided that the final terms and form of
any definitive agreement would be subject to the approval of the MMI Board.
 
    On May 12, 1997 through and including May 15, 1997, representatives of MMI
conducted due diligence on site at Unionamerica's offices in London. Its
advisors continued their due diligence investigation in the weeks that followed.
On May 19, 1997, representatives of Unionamerica conducted a due diligence
investigation of MMI at MMI's offices in Deerfield.
 
    On May 27, 1997, Mr. Becker and Mr. Orzech and Smith Barney met with Mr.
Spass and Mr. Steven B. Gruber, another Unionamerica director, along with
representatives from DLJ in New York, to discuss the terms of a potential
transaction. Discussion topics included, for both MMI and Unionamerica,
potential future premium writings and underwriting results, reserve levels, and
prospective investment returns. Also discussed were the form of consideration to
be offered in a transaction and the impact of a transaction on future MMI
earnings. The parties concluded with an understanding that the transaction would
be structured as a non-taxable stock-for-stock acquisition which qualified for
pooling-of-interest accounting treatment. MMI proposed an exchange ratio of 0.8,
and Unionamerica indicated that an exchange ratio of 0.8 was not sufficient.
While the meeting concluded without an agreement upon a specific exchange ratio,
both parties agreed that a transaction that provided improved future earnings
for MMI was desirable.
 
    In late May 1997, Mr. Becker and Mr. Spass, after consulting with Smith
Barney and DLJ, agreed in a teleconference upon the Exchange Ratio. The parties
then began to negotiate additional terms of the Acquisition Agreement. Such
meetings occurred frequently by teleconference over the following four weeks,
and included MMI management, Mr. Spass and Mr. Gruber, and MMI's and
Unionamerica's respective financial, tax and legal advisors. Additional terms
negotiated included Unionamerica director representation on the MMI Board,
conditions to closing, undertakings of Unionamerica affiliates to tender their
Unionamerica ADSs, covenants, representations and indemnification of the
parties, termination provisions, and other standard terms of a definitive
acquisition agreement.
 
    At a meeting on June 13, 1997, DLJ summarized for the Unionamerica Board the
discussions of previous months with other interested parties involving a variety
of different transaction structures, including structures in which the form of
consideration was all cash or a portion cash and a portion stock, as well as all
stock. At the meeting, DLJ circulated discussion materials in relation to the
Proposed Acquisition. The Board also received oral presentations on relevant
points from Unionamerica's U.K. and
 
                                       22
<PAGE>
U.S. legal advisors. A full discussion of all material aspects of the proposed
transaction took place and DLJ's consideration of the fairness of the
transaction was reviewed. The legal advisors present reviewed the U.K. and U.S.
statutory and fiduciary duties of the Unionamerica Board including the relevant
provisions of the Securities Act, the Exchange Act, the Companies Act, the U.K.
Financial Services Act 1986, and the City Code. An Acquisition Committee of the
Board comprising Mr. Sinclair, Mr. Cooper and Mr. Spass (the "Acquisition
Committee") was appointed to negotiate further the terms of the proposed
exchange offer and any acquisition agreement and report back to the Unionamerica
Board for its final approval of any acquisition agreement.
 
    At a meeting of the MMI Board on June 14, 1997, Mr. Orzech reported on the
current status of the Unionamerica acquisition. The MMI Board thoroughly
discussed the structure of the transaction, including the pooling-of-interests
versus purchase accounting treatment. Mr. Orzech displayed charts showing the
potential financial impact of this transaction on both MMI and Unionamerica for
the years 1996, 1997 and 1998. At that meeting, representatives of Smith Barney
made a presentation to the MMI Board summarizing certain financial analyses
performed by Smith Barney in connection with the MMI Board's consideration of
the Proposed Acquisition. For a summary of the material financial analyses
performed by Smith Barney and presented to the MMI Board, see "--Opinion of
Financial Advisor to MMI". The MMI Board then discussed various aspects of the
Proposed Acquisition, including structure and timing. Mr. Becker discussed
considerations for the investment community, including the possible financial
effect of the Proposed Acquisition on MMI.
 
    Mr. Becker reviewed the various material factors relating to the
transaction. The MMI Board then unanimously resolved that MMI acquire
Unionamerica pursuant to acquisition documents and/or an exchange offer
providing for the issuance by MMI, in a share-for-share exchange, of 0.836
shares of MMI Common Stock for each Unionamerica ADS, subject to the negotiation
of a definitive acquisition agreement and the approval thereof by the MMI Board.
The MMI Board further resolved to obtain a fairness opinion from Smith Barney
prior to executing a definitive acquisition agreement.
 
    At a meeting on June 24, 1997, the Unionamerica Board considered the
fairness opinion of DLJ and received oral reports of the negotiations with MMI
from the Acquisition Committee and the various advisors to the Board. The
Unionamerica Board unanimously approved the Offer set out in the Acquisition
Agreement and considered the terms of the Offer as being fair and in the best
interests of the shareholders and employees of Unionamerica as a whole, and
authorized the Acquisition Committee to approve any final minor amendments prior
to execution of the Acquisition Agreement on behalf of Unionamerica.
 
    On June 24, 1997, Smith Barney issued an opinion to the MMI Board to the
effect that, as of the date of such opinion and based upon and subject to
certain matters stated therein, the Exchange Ratio was fair, from a financial
point to view, to MMI.
 
    On June 24, 1997, the MMI Board held a telephonic meeting at which it
approved the Acquisition Agreement and the transactions contemplated thereby,
and also authorized the execution and delivery of the Acquisition Agreement.
 
    On June 25, 1997, MMI and Unionamerica each executed and delivered the
Acquisition Agreement and issued press releases announcing the Proposed
Acquisition.
 
TERMS OF THE OFFER AND PROPOSED ACQUISITION
 
    INTRODUCTION.  On June 25, 1997, MMI and Unionamerica entered into an
Acquisition Agreement pursuant to which, subject to the terms and conditions
stated therein and in this Prospectus and the accompanying Letter of
Transmittal, MMI agreed to offer 0.836 shares of MMI Common Stock for each
outstanding Unionamerica ADS. This Prospectus contains the formal offer by MMI.
 
                                       23
<PAGE>
    THE OFFER.  MMI hereby offers to acquire, on the terms and subject to the
conditions set out in this Prospectus and the accompanying Letter of Transmittal
(including if the Offer is revised, varied, extended or renewed, the terms and
conditions of any such revision, variation, extension or renewal), each
outstanding share of Unionamerica Common Stock (including shares represented by
Unionamerica ADSs) in exchange for 0.836 shares of MMI Common Stock. Each share
of MMI Common Stock issued in connection with the Offer will be accompanied by a
Right which will entitle the registered holder thereof to purchase from MMI a
Unit of Series B Preferred Stock at the Purchase Price, subject to adjustment,
pursuant to the Rights Agreement. The Offer which is being made to all
Unionamerica Securityholders (including U.S. Persons) will remain open until the
Expiration Date, including any extension thereof. The Offer and this Prospectus
are subject to the requirements of both the Panel and the Commission.
 
    UNDERTAKINGS.  MMI has received Undertakings to accept the Offer, subject to
certain conditions, from the Selling Stockholders in respect of not less than an
aggregate of 4,272,983 Unionamerica ADSs (representing 50.21% of Unionamerica's
outstanding ADSs as of October 31, 1997). For further information regarding
these Undertakings, see Appendix E--"Certain Additional Information Required
Under the City Code".
 
    NO FRACTIONAL SHARES.  No certificates or scrip representing fractional
shares of MMI Common Stock shall be issued upon the surrender for exchange of
Unionamerica ADSs, and such fractional share interests will not entitle the
owner thereof to vote or to any rights of a stockholder of MMI. As promptly as
practicable following the Expiration Date, including any extension thereof, the
Exchange Agent shall determine the excess of (x) the number of full shares of
MMI Common Stock delivered to the Exchange Agent by MMI pursuant to the Offer
over (y) the aggregate number of full shares of MMI Common Stock to be
distributed to holders of Unionamerica ADSs pursuant to the Offer (such excess
being herein called the "Excess Shares"). As soon as practicable after the
Expiration Date, including any extension thereof, the Exchange Agent, as agent
for the former holders of Unionamerica ADSs, shall sell the Excess Shares at
then prevailing prices on the NYSE, all in the manner provided below.
 
    The sale of the Excess Shares by the Exchange Agent shall be executed on the
NYSE through one or more member firms of the NYSE and shall be executed in round
lots to the extent practicable. Until the net proceeds of such sale or sales
have been distributed to the former holders of Unionamerica ADSs, the Exchange
Agent will hold such proceeds in trust for the former Unionamerica
Securityholders (the "Excess Shares Trust"). All commissions, transfer taxes and
other out-of-pocket transaction costs, including the expenses and compensation,
of the Exchange Agent incurred in connection with such sale of the Excess
Shares, shall be paid out of the Excess Shares Trust. The Exchange Agent shall
determine the portion of the Excess Shares Trust to which each former holder of
Unionamerica ADSs shall be entitled, if any, by multiplying the amount of the
aggregate net proceeds comprising the Excess Shares Trust by a fraction the
numerator of which is the amount of the fractional share interest to which such
former holder of Unionamerica ADSs is entitled and the denominator of which is
the aggregate amount of fractional share interests to which all former holders
of Unionamerica ADSs are entitled. As soon as practicable after the
determination of the amount of cash, if any, to be paid to former holders of
Unionamerica ADSs in respect of any fractional share interests of MMI Common
Stock, the Exchange Agent shall make available such amounts to such former
holders of Unionamerica ADSs.
 
    DEFERRED STOCK.  At the consummation of the Offer, Unionamerica will, in
accordance with Article 5 of the Unionamerica Articles, cause all of the issued
and outstanding shares of its Deferred Stock to be transferred to MMI (with the
exception of one share of Deferred Stock which will be transferred to a Person
designated by MMI to hold such share as nominee for MMI) in exchange for one
share of MMI Common Stock for each 25,000 shares of Deferred Stock outstanding.
As of the date of this Prospectus, Unionamerica has 50,000 shares of Deferred
Stock outstanding.
 
    ACQUISITION OF REMAINING UNIONAMERICA ADSS.  If, on or before March 6, 1998,
as a result of the Offer or otherwise, MMI acquires or contracts to acquire
Unionamerica ADSs representing at least 90% of the
 
                                       24
<PAGE>
Unionamerica ADSs to which the Offer relates then (i) MMI will be entitled, and
intends, to effect a Compulsory Acquisition to compel the purchase of the
remainder of the outstanding Unionamerica ADSs on the same terms as those
offered in the Offer in accordance with Section 428 to 430F of the Companies
Act; and/or (ii) a holder of Unionamerica ADSs may require MMI to purchase his
or her Unionamerica ADSs on the same terms as those offered in the Offer in
accordance with Sections 430A and 430B of the Companies Act. See Appendix
F--"Certain Provisions of the Companies Act". See "Prospectus
Summary--Dissenters' Rights--Unionamerica".
 
    If for any reason the Compulsory Acquisition is not made, MMI will evaluate
its other alternatives to obtain the remaining Unionamerica ADSs not purchased
pursuant to the Offer. Such alternatives could include acquiring additional
Unionamerica ADSs in the open market, in a privately negotiated transaction, in
another tender or exchange offer or by means of the DGCL, a scheme of
arrangement under the Companies Act, or otherwise. Any such additional
acquisitions could be for a consideration greater or less than, or equal to, the
consideration for Unionamerica ADSs in the Offer, and could be for cash or other
consideration. Prior to making any such acquisitions, MMI would consider the
effect such acquisitions, and the methods employed, would have on the Proposed
Acquisition, including the impact on the tax consequences to MMI and the
Unionamerica Securityholders, and the pooling-of-interests treatment. However,
under the City Code, except with the consent of the Panel, if the Offer becomes
or is declared wholly unconditional, neither MMI nor any Person acting or deemed
to be acting in concert with MMI for the purposes of the Offer may acquire any
Unionamerica ADSs on better terms than those of the Offer within six months of
the termination of the Offer.
 
    PROPOSED ACQUISITION.  Following the closing of the Proposed Acquisition,
Unionamerica will become a wholly-owned Subsidiary of MMI. It is MMI's present
intention to continue the existing management and business plans of Unionamerica
after the Proposed Acquisition, and to continue to operate Unionamerica as a
distinct business entity at its present location in London.
 
    APPROVAL OF HOLDERS OF MMI COMMON STOCK.  The Offer is conditioned upon the
approval of the issuance of shares of MMI Common Stock pursuant to the Offer by
a majority of the outstanding shares of MMI Common Stock voting on such matter.
MMI, through the MMI Board, will duly call, give notice of, convene and hold the
MMI Special Meeting for the purpose of obtaining the MMI Stockholders' Approval
as soon as reasonably practicable after the date of this Prospectus.
 
    MMI COMMON STOCK.  The shares of MMI Common Stock to be issued pursuant to
the Offer will rank pari passu in all respects with the issued and outstanding
MMI Common Stock, including the right to receive all future dividends (payable
in U.S. dollars), if any, and other distributions having a record date after the
Expiration Date, including any extension thereof. Application will be made to
list the MMI Common Stock to be issued in connection with the Offer on the NYSE.
 
    TAX TREATMENT.  MMI and Unionamerica intend that the exchange of shares of
MMI Common Stock for Unionamerica ADSs pursuant to the Offer will be treated as
a tax-free reorganization as described in Section 368(a)(1)(B) of the IRC. See
"The Offer--Tax Consequences of the Offer".
 
    POOLING-OF-INTERESTS ACCOUNTING TREATMENT.  It is contemplated that the
Proposed Acquisition will be accounted for as a pooling-of-interests for
accounting purposes under GAAP. Under this accounting treatment, the accounts of
MMI and the accounts of Unionamerica will be combined for all past and future
periods presented after the Offer becomes or is declared unconditional in all
respects.
 
    AFFILIATES' RESTRICTIONS ON SALE OF SHARES OF MMI COMMON STOCK.  The shares
of MMI Common Stock to be issued pursuant to the Offer have been registered
under the Securities Act pursuant to a Registration Statement on Form S-4,
thereby allowing such securities to be traded without restriction by any former
holder of Unionamerica ADSs if such former holder (i) is not deemed to be an
"affiliate" (as defined for the purposes of Rule 144 under the Securities Act)
of Unionamerica within 30 calendar days prior to the
 
                                       25
<PAGE>
date the Offer is declared unconditional in all respects, and (ii) does not
become an affiliate or officer of MMI pursuant to the Offer.
 
    In order to ensure that one of the requirements of pooling-of-interests
accounting is met, certain directors and executive officers of Unionamerica have
executed and delivered, and prior to the date of this Prospectus, certain other
directors and executive officers shall have executed and delivered, an Affiliate
Letter to MMI, pursuant to which they agreed not to sell any shares of MMI
Common Stock or Unionamerica Securities during the time period that would cause
the violation of the requirements for pooling-of-interests accounting, which
period ends when the financial results of the combined operations of MMI and
Unionamerica covering a period of at least 30 calendar days are publicly
released by MMI.
 
    ELECTION OF REPRESENTATIVES TO THE MMI BOARD.  MMI has agreed that, at or
prior to the consummation of the Proposed Acquisition, MMI shall increase the
size of its Board by two members to 14 members. Upon consummation of the
Proposed Acquisition, MMI shall use its best efforts to nominate both Ian G.
Sinclair and Robert A. Spass to the MMI Board. At MMI's 1998 Annual Meeting of
Stockholders, MMI shall use its best efforts to nominate the aforesaid
individuals to the MMI Board and cause them to be elected to one full three-year
term. Ian G. Sinclair was Managing Director - Underwriting of UICL, from 1984
until December 31, 1996, when he was appointed Chief Executive Officer of UICL.
He has been a Director of UICL since 1977 and of Unionamerica since September
10, 1993. From 1973 to 1977, he was an underwriter with UICL focusing on
casualty business. Robert A. Spass has been a Director of Unionamerica since
September 10, 1993. From February 1994 to the present, he has served as a
founder and Managing Partner of IPA. From March 1990 to the present, he has been
President and Chief Executive Officer of IIA. From December 1988 to March 1990,
he was a Director of Salomon Brothers Inc. He is also a Director of Superior
National Insurance Group, Inc., Highlands Insurance Group Inc., Tarquin plc and
Charman Group Ltd.
 
    UNIONAMERICA OPTIONS.  The Offer extends to any Unionamerica ADSs
representing any shares of Unionamerica Common Stock which are unconditionally
issued or allotted upon the exercise of options granted under the Unionamerica
Share Option Schemes or otherwise while the Offer remains open for acceptance.
In addition, a proposal is being made to Option holders under the Unionamerica
Share Option Schemes in respect of unexercised options pursuant to which such
Option holders may elect (i) to exercise their existing Unionamerica options
immediately following the Offer becoming or being declared unconditional in all
respects, and then tender the Unionamerica ADSs received upon such exercise in
the Offer, or (ii) to rollover their existing options. Option holders who elect
to rollover their options will receive comparable options from MMI on the terms
of the existing relevant Unionamerica Share Option Scheme, such options to be
issued pursuant to MMI's Amended 1993 Employee Stock Plan. Entitlements to
fractional shares of MMI Common Stock will be treated as set forth above. The
proposal to Option holders is conditioned upon the Offer becoming or being
declared unconditional in all respects.
 
    CONDITIONS OF THE OFFER.  In addition to the conditions discussed above, the
Offer is subject to the following additional conditions (collectively, the
"Conditions"):
 
    (a) the issuance of shares in connection with the Offer having been approved
       by the MMI stockholders under the DGCL;
 
    (b) the Minimum Acceptance Condition having been met, that is, at least 90%
       on a fully diluted basis in nominal value of voting shares of
       Unionamerica Common Stock and all of the non-voting shares of
       Unionamerica Common Stock to which the Offer relates (such expression to
       be construed in accordance with Sections 428 through 430F of the
       Companies Act) having been validly tendered and not properly withdrawn
       prior to the expiration of the Offer;
 
    (c) any waiting period (and any extension thereof) applicable to the
       consummation of the transactions contemplated by the Acquisition
       Agreement under the HSR Act having expired or been terminated;
 
                                       26
<PAGE>
    (d) all authorizations, orders, grants, recognitions, confirmations,
       permits, consents, clearances, permissions, approvals, waivers and
       actions of, filings with and notices to, any Governmental or Regulatory
       Authority or any other public or private third parties required of MMI,
       Unionamerica or any of their Subsidiaries to consummate the transactions
       contemplated by the Acquisition Agreement, other than those the failure
       of which to be obtained or taken could not be reasonably expected to have
       a material adverse effect on MMI and its Subsidiaries or Unionamerica and
       its Subsidiaries, in each case taken as a whole, or on the ability of MMI
       and Unionamerica to consummate the transactions contemplated by the
       Acquisition Agreement having been obtained or taken; provided that no
       such permit, consent, approval, waiver or action shall be subject to any
       condition which could reasonably be expected prior to or following the
       date on which the Offer becomes or is declared unconditional in all
       respects to have a material adverse affect on MMI and its Subsidiaries
       taken as a whole, or on Unionamerica and its Subsidiaries taken as a
       whole, or otherwise result in a material diminution of the benefits to
       MMI of the transactions contemplated by the Acquisition Agreement;
 
    (e) the Office of Fair Trading indicating, in terms reasonably satisfactory
       to MMI, that it is not the intention of the Secretary of State for Trade
       and Industry of the U.K. to refer the Proposed Acquisition or any matter
       relating thereto to the MMC;
 
    (f) the Secretary of State for Trade and Industry of the U.K. confirming, in
       terms reasonably satisfactory to MMI, that in accordance with Section 61
       of the U.K. Insurance Companies Act 1982 there is no objection to MMI and
       any relevant stockholders or officers of MMI becoming controllers of
       Unionamerica or, in the absence of such confirmation in relation to any
       such Person, the period during which such Secretary of State may serve a
       notice of objection pursuant to Section 61 of the U.K. Insurance
       Companies Act 1982 in relation to such Person having elapsed without the
       Secretary of State having served any such notice of objection;
 
    (g) the Council of Lloyd's approving MMI and any relevant stockholders of
       MMI as controllers of Jago Capital Limited (a Lloyd's corporate member)
       and Jago Managing Agency Limited (a Lloyd's managing agency) in terms
       reasonably satisfactory to MMI;
 
    (h) the U.K. Inland Revenue issuing notification pursuant to Section 138 of
       the Taxation of Chargeable Gains Act 1992 of the U.K. that it is
       satisfied that the transactions contemplated by the Acquisition Agreement
       will be effected for bona fide commercial reasons and will not form part
       of any such scheme or arrangements as are mentioned in Section 137 of the
       Taxation and Chargeable Gains Act 1992 of the U.K.;
 
    (i) the Registration Statement becoming and continuing to be effective prior
       to and following the date on which the Offer becomes or is declared
       unconditional in all respects and no stop order suspending effectiveness
       of the Registration Statement being issued, no action, suit, proceeding
       or investigation by the Commission to suspend the effectiveness thereof
       being initiated and be continuing or, to the knowledge of MMI or
       Unionamerica, threatened, and all necessary approvals under state
       securities laws relating to the issuance or trading of the MMI Common
       Stock to be issued to Unionamerica Securityholders in connection with the
       Offer having been received;
 
    (j) the MMI Common Stock to be issued pursuant to the Offer and such other
       shares of MMI Common Stock required to be reserved for issuance pursuant
       to the Acquisition Agreement, if any, having been approved for listing on
       the NYSE, subject to official notice of issuance;
 
    (k) the opinion of DLJ, dated June 25, 1997 (included as Appendix C) to the
       effect that, as of June 25, 1997, the Exchange Ratio is fair from a
       financial point of view to the Unionamerica Securityholders not having
       been withdrawn (see "Opinion of Financial Advisor to Unionamerica");
 
                                       27
<PAGE>
    (l) the opinion of Paul, Weiss, Rifkind, Wharton & Garrison, special U.S.
       tax counsel to Unionamerica, with respect to the qualification of the
       Proposed Acquisition under Section 368(a)(1)(B) of the IRC not having
       been withdrawn;
 
    (m) there not having been any law or order promulgated, entered, enforced,
       enacted, issued or deemed applicable to the transactions contemplated by
       the Acquisition Agreement by any court of competent jurisdiction or other
       competent Governmental or Regulatory Authority which, directly or
       indirectly:
 
        (i) prohibits or imposes any material limitations on the ownership or
            operation by MMI (or that of any of its Subsidiaries or affiliates)
            of any portion of its business or assets (or those of Unionamerica
            or any of its Subsidiaries) which is material to the business of
            Unionamerica and its Subsidiaries taken as a whole, or material to
            the business of MMI and its Subsidiaries taken as a whole, or
            compels MMI (or its Subsidiaries or affiliates) to dispose of or
            hold separate any portion of the business or assets of Unionamerica
            or any of its Subsidiaries which is material to the business of
            Unionamerica and its Subsidiaries taken as a whole or material to
            the business of MMI and its Subsidiaries taken as a whole, or
            otherwise results in a material diminution of the benefits to MMI of
            the transactions contemplated by the Acquisition Agreement;
 
        (ii) prohibits, restrains or makes illegal any of the transactions
             contemplated by the Acquisition Agreement;
 
       (iii) imposes material limitations on the ability of MMI (or any of its
             Subsidiaries or affiliates) effectively to acquire or to hold or
             exercise full rights of ownership of Unionamerica Securities
             including, without limitation, the right to vote such Unionamerica
             Securities on all matters properly presented to Unionamerica
             Securityholders;
 
        (iv) imposes limitations on the ability of MMI (or any of its
             Subsidiaries or affiliates) effectively to control in any material
             respect any material portion of the business or assets of
             Unionamerica and its Subsidiaries taken as a whole, or any material
             portion of the business or assets of MMI and its Subsidiaries taken
             as a whole; or
 
        (v) has the effect of making illegal or otherwise restricting,
            preventing or prohibiting consummation of the transactions
            contemplated by the Acquisition Agreement;
 
    (n) there not having been instituted or be pending any action or proceeding
       (whether civil or criminal) before any Person or Governmental or
       Regulatory Authority (or any such action threatened by any Person or
       Governmental or Regulatory Authority) which (i) in the case of any such
       action or proceeding brought by any Governmental or Regulatory Authority,
       seeks any order, decree or injunction having any effect set forth in
       paragraph (m) above or (ii) in the case of any such action or proceeding
       brought by any other Person, could reasonably be expected to result in
       any order, decree or injunction having any effect set forth in paragraph
       (m) above;
 
    (o) there not having occurred and be continuing:
 
        (i) any general suspension of trading in, or limitation on prices for,
            securities on any U.S. national securities exchange or in the
            over-the-counter market;
 
        (ii) a declaration of a banking moratorium or any suspension of payments
             in respect of banks in the U.S. or the U.K. (whether or not
             mandatory);
 
       (iii) any limitation (whether or not mandatory) by any Governmental or
             Regulatory Authority on the extension of credit by banks or other
             financial institutions;
 
                                       28
<PAGE>
        (iv) a commencement of war or armed hostilities or other national or
             international crisis directly or indirectly involving the U.S.
             having a significant adverse effect on the functionality of the
             financial markets in the U.S.; or
 
        (v) in the case of any of the foregoing existing on the date of the
            Acquisition Agreement, in the good faith judgment of MMI, a material
            acceleration or worsening thereof;
 
    (p) the representations and warranties made by Unionamerica in the
       Acquisition Agreement that are subject to, or qualified by, "material
       adverse effect", "material adverse change" or other materiality
       qualification being true and correct, and the representations and
       warranties made by Unionamerica in the Acquisition Agreement that are not
       so qualified being true and correct except in any respect which could not
       reasonably be expected to have a material adverse effect on Unionamerica
       and its Subsidiaries taken as a whole, in each case as of the date on
       which the Offer becomes or is declared unconditional in all respects;
 
    (q) Unionamerica performing and complying in all material respects (without
       any reference to a materiality qualification contained therein) with all
       obligations and covenants required to be performed or complied with by it
       under the Acquisition Agreement on or before the date on which the Offer
       becomes or is declared unconditional in all respects;
 
    (r) the opinion of Smith Barney dated June 24, 1997 to the effect that the
       Exchange Ratio is fair to MMI from a financial point of view not having
       been withdrawn;
 
    (s) each of the irrevocable Undertakings executed and delivered to MMI by
       the Selling Stockholders along with all relevant letters of direction and
       legal opinions relating thereto being in full force and effect and not
       having been withdrawn;
 
    (t) neither Unionamerica nor its affiliates having taken any action which
       has prevented or would prevent MMI from treating the acquisition of
       Unionamerica as a pooling-of-interests in accordance with GAAP;
 
    (u) the Acquisition Agreement not having been terminated in accordance with
       its terms and remaining in full force and effect;
 
    (v) the Unionamerica Securityholders having approved and adopted a
       resolution at an extraordinary general meeting of Unionamerica (or at any
       adjournment thereof) to amend the Unionamerica Articles to disapply
       certain voting restrictions (the "IRC Voting Restrictions") contained in
       Articles 75 and 76 which would otherwise apply to MMI following the
       closing of the Proposed Acquisition and to remove the rights of the
       Designated Shareholders (as defined in the Unionamerica Articles) to
       appoint directors to the Unionamerica Board;
 
    (w) each of the Designated Affiliates (as defined in Appendix G--"Key
       Definitions") having executed and delivered to MMI an Affiliate Letter,
       there having been no breaches of any of the terms of such agreements by
       any Designated Affiliate prior to the date on which the Offer becomes or
       is declared unconditional in all respects, and the Affiliate Letters
       remaining in full force and effect;
 
                                       29
<PAGE>
    (x) the representations and warranties made by MMI in the Acquisition
       Agreement that are subject to, or qualified by, "material adverse
       effect," "material adverse change" or other materiality qualification
       being true and correct, and the representations and warranties made by
       MMI in the Acquisition Agreement that are not so qualified being true and
       correct except in any respect which could not reasonably be expected to
       have a material adverse effect on MMI and its Subsidiaries taken as a
       whole, in each case as of the date on which the Offer becomes or is
       declared unconditional in all respects; and
 
    (y) MMI performing and complying in all material respects (without any
       reference to a materiality qualification contained therein) with all
       obligations and covenants required to be performed or complied with by it
       under the Acquisition Agreement on or before the date on which the Offer
       becomes or is declared unconditional in all respects.
 
    The Conditions to the Offer set forth in (c), (f), (g), (h) and (v) above
have been satisfied.
 
    MMI reserves the right, subject to the provisions of the Acquisition
Agreement, to waive, in whole or in part, all or any of Conditions (a) to (w)
(other than those which have been previously satisfied) provided that MMI may
only waive those of Conditions (a) to (l) which remain unsatisfied with the
prior written consent of Unionamerica. Unionamerica reserves the right, subject
to the provisions of the Acquisition Agreement, to waive, in whole or in part,
all or any of Conditions (x) and (y). Reducing the Minimum Acceptance Condition
requires the prior written consent of Unionamerica and the Minimum Acceptance
Condition may not be reduced such as to have the effect of reducing the 90%
threshold specified in Condition (b) above to an amount which is 50% or less.
 
    The Offer will lapse if it is referred to the MMC before 12 midnight, New
York City time, on the Expiration Date, including any extension thereof, or the
date on which the Offer becomes or is declared unconditional in all respects,
whichever is the later and if the Offer so lapses the Offer will cease to be
capable of further acceptance and accepting Unionamerica Securityholders and MMI
will cease to be bound by Letters of Transmittal submitted before the time when
the Offer lapses.
 
    OFFER PERIOD.  MMI hereby offers to purchase, upon the terms and subject to
the Conditions (including, if the Offer is revised, varied, extended or renewed,
the terms and conditions of any such revision, variation, extension or renewal),
all Unionamerica ADSs validly tendered pursuant to the Offer and not validly
withdrawn on or prior to the Expiration Date, including any extension thereof,
in accordance with the procedures set forth in this Prospectus and the Letter of
Transmittal. The term "Expiration Date" shall mean 12 midnight, New York City
time, on December 5, 1997, unless and until MMI shall have extended the
Expiration Date in accordance with the terms of the Acquisition Agreement, in
which event the term "Expiration Date" shall mean the latest time and date at
which the period during which the Offer is open for acceptance, as so extended
by MMI, shall be terminated or expire. The Expiration Date shall be a minimum of
20 business days from the date of commencement of the Offer. If all the
Conditions have not been satisfied or, where permitted, waived, by 12 midnight,
New York City time, on the date being 60 calendar days from the date of
commencement of the Offer, in the absence of a competitive situation and/or
unless the Panel otherwise agrees, the Offer will lapse.
 
    The purchase of Unionamerica ADSs pursuant to the Offer is subject to the
satisfaction or, where permitted, waiver of all the Conditions including, among
other things, the Minimum Acceptance Condition. The procedures for the waiver of
these Conditions are governed by the Acquisition Agreement. If, on the
Expiration Date, any Condition shall not have been satisfied or, where
permitted, waived, MMI shall, no later than 8.30 a.m. (London time), 3.30 a.m.
(New York City time) on the following business day elect, subject to the terms
of the Acquisition Agreement, to (i) extend the Expiration Date and, subject to
applicable withdrawal rights, retain all tendered Unionamerica ADSs until the
Expiration Date, as so extended, or (ii) terminate the Offer and not purchase
any Unionamerica ADSs and promptly return all tendered Unionamerica ADSs to
tendering Unionamerica Securityholders.
 
                                       30
<PAGE>
    If the Offer becomes or is declared unconditional in all respects so that
Unionamerica ADSs are purchased by MMI at the Expiration Date, including any
extension thereof, the Offer will be terminated. See "The Offer--Acquisition of
Remaining Unionamerica ADSs."
 
    This Prospectus and the Letter of Transmittal are being mailed by MMI to
holders of record of Unionamerica ADSs, and are being furnished by MMI to
brokers, dealers, commercial banks, trust companies and similar Persons, whose
names, or the name of whose nominees, appear as holders of record for subsequent
transmittal to beneficial owners of Unionamerica ADSs. Any accidental omission
to dispatch this Prospectus, a Letter of Transmittal or any notice required to
be dispatched under the terms of the Offer to, or any failure to receive the
same by, any Person to whom the Offer is, or should be, made, will not
invalidate the Offer.
 
PROCEDURES FOR TENDERING UNIONAMERICA ADSS
 
    There is a Letter of Transmittal for use in connection with the Offer. This
section should be read together with the instructions to the Letter of
Transmittal. The provisions of this section shall be deemed to be incorporated
in, and form a part of, the Letter of Transmittal. The instructions printed on
the Letter of Transmittal shall be deemed to form part of the terms of the
Offer.
 
    VALID TENDER OF UNIONAMERICA ADSS.  For a holder of Unionamerica ADSs to
tender Unionamerica ADSs validly pursuant to the Offer, either (i) a properly
completed and duly executed Letter of Transmittal, together with any required
signature guarantees and any other required documents, must be received by the
Exchange Agent at its address set out on the back cover page of this Prospectus,
and Unionamerica ADRs evidencing such Unionamerica ADSs must be either received
by the Exchange Agent at such address or delivered pursuant to the procedures
for book-entry transfer set out below (and a confirmation of receipt of such
transfer received by the Exchange Agent) or (ii) such holder must comply with
the "Guaranteed Delivery Procedures" (as defined below). All Letters of
Transmittal, Unionamerica ADRs evidencing Unionamerica ADSs and other required
documents delivered to the Exchange Agent by Unionamerica Securityholders will
be deemed (without any further action by the Exchange Agent) to constitute
acceptance of the Offer by such Unionamerica Securityholder with respect to such
Unionamerica ADSs subject to the terms and conditions set out in the Letter of
Transmittal. The acceptance of the Offer by a tendering Unionamerica
Securityholder pursuant to the procedures described above, subject to the
withdrawal rights described below, will be deemed to constitute a binding
agreement between such tendering Unionamerica Securityholder and MMI upon the
terms and subject to the Conditions of the Offer. IF A UNIONAMERICA ADS HAS BEEN
TENDERED BY A UNIONAMERICA SECURITYHOLDER, THE UNIONAMERICA COMMON STOCK
REPRESENTED BY SUCH UNIONAMERICA ADS MAY NOT BE TENDERED INDEPENDENTLY. A LETTER
OF TRANSMITTAL AND OTHER REQUIRED DOCUMENTS CONTAINED IN AN ENVELOPE POSTMARKED
IN JAPAN OR AUSTRALIA OR OTHERWISE APPEARING TO MMI OR ITS AGENTS TO HAVE BEEN
SENT FROM JAPAN OR AUSTRALIA WILL NOT CONSTITUTE A VALID ACCEPTANCE OF ANY
OFFER.
 
    BOOK-ENTRY TRANSFER.  The Exchange Agent will establish an account at the
Book-Entry Transfer Facilities with respect to Unionamerica ADSs held in
book-entry form for purposes of the Offer within two business days after the
date of this Prospectus. Any financial institution that is a participant in any
of the Book-Entry Transfer Facilities' systems may make book-entry delivery of
Unionamerica ADSs by causing a Book-Entry Transfer Facility to transfer such
Unionamerica ADSs into the Exchange Agent's account at such Book-Entry Transfer
Facility in accordance with that Book-Entry Transfer Facility's procedure for
such transfer. Although delivery of Unionamerica ADSs may be effected through
book-entry transfer into the Exchange Agent's account at a Book-Entry Transfer
Facility, either (i) the Letter of Transmittal, properly completed and duly
executed, together with any required signature guarantees or (ii) an Agent's
Message (as defined below), and, in either case, any other required documents,
must in any case be transmitted to, and received by, the Exchange Agent at its
address set out on the back cover of this Prospectus before Unionamerica ADSs
will be either counted as a valid acceptance, for the purposes of the Minimum
Acceptance Condition, or exchanged, or such holder must comply with the
Guaranteed Delivery
 
                                       31
<PAGE>
Procedures (as described below). The term "Agent's Message" means a message
transmitted by a Book-Entry Transfer Facility to, and received by, the Exchange
Agent and forming a part of a Book-Entry Confirmation that states that such
Book-Entry Transfer Facility has received an express acknowledgment from the
participant in such Book-Entry Transfer Facility tendering the Unionamerica ADSs
that such participant has received and agrees to be bound by the terms of the
Letter of Transmittal and that MMI may enforce such agreement against the
participant. Delivery of documents to a Book-Entry Transfer Facility in
accordance with such Book-Entry Transfer Facility's procedures does not
constitute delivery to the Exchange Agent.
 
    NO ACKNOWLEDGEMENT OF RECEIPT OF ANY LETTER OF TRANSMITTAL OR OTHER REQUIRED
DOCUMENTS WILL BE GIVEN BY, OR ON BEHALF OF, MMI. THE METHOD OF DELIVERY OF
UNIONAMERICA ADRS AND ALL OTHER REQUIRED DOCUMENTS IS AT THE OPTION AND RISK OF
THE TENDERING UNIONAMERICA SECURITYHOLDER. UNIONAMERICA ADSS WILL BE DEEMED
DELIVERED ONLY WHEN THE UNIONAMERICA ADRS REPRESENTING SUCH UNIONAMERICA ADSS
ARE ACTUALLY RECEIVED BY THE EXCHANGE AGENT. IF DELIVERY IS BY MAIL, REGISTERED
MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS RECOMMENDED. IN
ADDITION, YOU SHOULD ALLOW AT LEAST FIVE BUSINESS DAYS FOR DELIVERY BY MAIL. IN
ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY AND IN
ANY EVENT TO ENSURE DELIVERY BY NO LATER THAN THE EXPIRATION DATE.
 
    SIGNATURE GUARANTEES.  No signature guarantee is required on the Letter of
Transmittal if: (i) the Letter of Transmittal is signed by the registered holder
of the Unionamerica ADSs tendered therewith and such registered holder has not
completed either the box entitled "Special Delivery Instructions" or the box
entitled "Special Exchange Instructions" in the Letter of Transmittal or (ii)
such Unionamerica ADSs are tendered for the account of an Eligible Institution.
In all other cases, all signatures on Letters of Transmittal must be guaranteed
by an Eligible Institution. See the instructions to the Letter of Transmittal.
 
    If the Unionamerica ADSs are registered in the name of a person other than
the person who signs the Letter of Transmittal, or if shares of MMI Common Stock
are to be issued to a person other than the registered owner of the Unionamerica
ADSs surrendered, then the tendered Unionamerica ADRs must be endorsed or
accompanied by appropriate stock powers, signed exactly as the name or names of
the registered owner or owners appear on the Unionamerica ADRs, with the
signatures on the Unionamerica ADRs or stock powers guaranteed as aforesaid. See
the instructions to the Letter of Transmittal.
 
    PARTIAL TENDERS.  If fewer than all of the Unionamerica ADSs evidenced by
any Unionamerica ADRs delivered to the Exchange Agent are to be tendered, the
holder thereof should so indicate in the Letter of Transmittal by filling in the
number of Unionamerica ADSs which are to be tendered in the box entitled "Number
of Unionamerica ADSs Tendered". In such case, a new Unionamerica ADR for the
remainder of the Unionamerica ADSs represented by the old Unionamerica ADR will
be sent to the person(s) signing such Letter of Transmittal (or delivered as
such person properly indicates thereon) as promptly as practicable following the
date the tendered Unionamerica ADSs are purchased. All Unionamerica ADSs
delivered to the Exchange Agent will be deemed to have been tendered unless
otherwise indicated. See the instructions to the Letter of Transmittal. In the
case of partial tenders, Unionamerica ADSs not tendered will not be reissued to
a person other than the registered holder.
 
    GUARANTEED DELIVERY PROCEDURES.  If a Unionamerica Securityholder desires to
tender Unionamerica ADSs pursuant to the Offer and the Unionamerica ADRs
evidencing such Unionamerica ADSs are not immediately available or the
procedures for book-entry transfer cannot be completed on a timely basis, or if
time will not permit all required documents to reach the Exchange Agent prior to
the Expiration Date, such holder's tender of Unionamerica ADSs may be effected
if all the following conditions are met (the "Guaranteed Delivery Procedures"):
 
        (i) such tender is made by or through an Eligible Institution;
 
                                       32
<PAGE>
        (ii) a properly completed and duly executed Notice of Guaranteed
    Delivery substantially in the form provided by MMI is received by the
    Exchange Agent, as provided below, prior to the Expiration Date; and
 
       (iii) the Unionamerica ADRs evidencing all tendered Unionamerica ADSs
    (or, in the case of Unionamerica ADSs held in book-entry form, timely
    confirmation of the book-entry transfer of such Unionamerica ADSs into the
    Exchange Agent's account at a Book-Entry Transfer Facility as described
    above), together with a properly completed and duly executed Letter of
    Transmittal with any required signature guarantees and any other documents
    required by the Letter of Transmittal, are received by the Exchange Agent
    within three NYSE trading days after the date of execution of such Notice of
    Guaranteed Delivery.
 
    The Notice of Guaranteed Delivery may be delivered by hand or mailed to the
Exchange Agent and must include a signature guarantee by an Eligible Institution
in the form set out in such Notice of Guaranteed Delivery.
 
    Notwithstanding any other provision hereof, delivery of shares of MMI Common
Stock for Unionamerica ADSs exchanged pursuant to the Offer will in all cases be
made only after timely receipt by the Exchange Agent of the Unionamerica ADRs
evidencing such Unionamerica ADSs (or, in the case of Unionamerica ADSs held in
book-entry form, timely confirmation of a book-entry transfer of such
Unionamerica ADSs into the Exchange Agent's account at a Book-Entry Transfer
Facility pursuant to the procedures set out above), together with a properly
completed and duly executed Letter of Transmittal with any required signature
guarantees (or, in the case of a book-entry transfer, an Agent's Message) and
any other required documents.
 
    RECEIPT OF A NOTICE OF GUARANTEED DELIVERY WILL NOT BE TREATED AS A VALID
ACCEPTANCE FOR THE PURPOSE OF SATISFYING THE MINIMUM ACCEPTANCE CONDITION. TO BE
COUNTED TOWARDS SATISFACTION OF SUCH REQUIREMENT, THE UNIONAMERICA ADRS
EVIDENCING UNIONAMERICA ADSS REFERRED TO IN THE NOTICE OF GUARANTEED DELIVERY
MUST BE RECEIVED BY THE EXCHANGE AGENT (OR, IN THE CASE OF UNIONAMERICA ADSS
HELD IN BOOK-ENTRY FORM, TIMELY CONFIRMATION OF A BOOK-ENTRY TRANSFER OF SUCH
UNIONAMERICA ADSS INTO THE EXCHANGE AGENT'S ACCOUNT AT A BOOK-ENTRY TRANSFER
FACILITY PURSUANT TO THE PROCEDURES SET OUT ABOVE), TOGETHER WITH A DULY
EXECUTED LETTER OF TRANSMITTAL WITH ANY REQUIRED SIGNATURE GUARANTEES (OR, IN
THE CASE OF A BOOK-ENTRY TRANSFER, AN AGENT'S MESSAGE) AND ANY OTHER REQUIRED
DOCUMENTS.
 
    APPOINTMENT AS PROXY.  By executing the Letter of Transmittal as set out
above, the tendering Unionamerica Securityholder will agree that effective from
and after the date the Offer becomes or is declared unconditional in all
respects and subject to applicable withdrawal rights, (i) MMI shall be entitled
to direct the exercise of any votes attaching to any Unionamerica ADSs, in
respect of which the Offer has been accepted or is deemed to have been accepted
and any other rights and privileges attaching to such Unionamerica ADSs and (ii)
the execution of the Letter of Transmittal and its delivery to the Exchange
Agent will constitute (a) an authority to Unionamerica and the Exchange Agent or
their respective agents from the tendering Unionamerica Securityholder to send
any notice, circular, warrant, document or other communication, which may be
sent to him or her as a Unionamerica Securityholder, to MMI at its registered
office, (b) an authority to MMI or its agent to sign any consent to short notice
of a general meeting or separate class meeting on behalf of the tendering
Unionamerica Securityholder and/or to execute a form of proxy in respect of such
Unionamerica ADSs appointing any person nominated by MMI to attend general
meetings or separate class meetings of Unionamerica (or any adjournments
thereof) and to exercise the votes attaching to such Unionamerica ADSs on the
holder's behalf and (c) the agreement of the tendering Unionamerica
Securityholder not to exercise any of such rights without the consent of MMI and
the irrevocable undertaking of the tendering Unionamerica Securityholder not to
appoint a proxy for or to attend general meetings or separate class meetings.
 
    VALIDITY OF ACCEPTANCES.  Subject to the City Code, MMI reserves the right
to treat as valid in whole or in part any acceptance of the Offer which is not
entirely in order or which is not accompanied by the
 
                                       33
<PAGE>
relevant Unionamerica ADR and/or other document(s) of title or which is received
by it at a place or places other than as set out in the Prospectus or the Letter
of Transmittal. In that event, the consideration under the Offer will only be
dispatched when the acceptance is entirely in order and the relevant
Unionamerica ADR or other document(s) of title or indemnities satisfactory to
MMI has/have been received.
 
    If the Offer lapses, all documents tendered will be returned within 14
calendar days thereafter.
 
    If you are in any doubt about the procedure for acceptance, please telephone
the Exchange Agent at the telephone number set out on the back cover page of
this Prospectus.
 
    Any omission or failure to dispatch this Prospectus or the Letter of
Transmittal or any notice required to be dispatched under the terms of the Offer
to, or any failure to receive the same by, any Person to whom the Offer is or
should be made, shall not invalidate the Offer in any way or create any
implication that the Offer has not been made to any such Person. Additional
copies of this Prospectus and the Letter of Transmittal may be obtained from the
Exchange Agent at the address and telephone number set out on the back cover
page of this Prospectus. No acknowledgement of receipt of any Letter of
Transmittal, ADR and/or other documents of title will be given.
 
    All powers of attorney, appointments of agents and authorities on the terms
conferred by or referred to in this Prospectus or in the Letter of Transmittal
are given by way of security for the performance of the obligations of the
Unionamerica Securityholder concerned and are irrevocable in accordance with
Section 4 of the U.K. Powers of Attorney Act 1971, except in the circumstance
where a donor validly withdraws his or her acceptance.
 
    The terms, provisions, instructions and authorities contained in or deemed
to be contained in the Letter of Transmittal constitute part of the terms of the
Offer.
 
    Except with the consent of the Panel, settlement of the consideration due
under the Offer will be made in full in accordance with the terms of the Offer
without regard to any lien, right of set-off, counterclaim or other analogous
right to which MMI may otherwise be, or claim to be, entitled as against a
Unionamerica Securityholder.
 
    WITHDRAWAL RIGHTS.  Unionamerica Securityholders (other than the Selling
Stockholders) will have the right to withdraw any tendered Unionamerica ADSs
until the Expiration Date, including any extension thereof. Subject to the terms
of the Acquisition Agreement, MMI expressly reserves the right (but will not be
obligated) at any time or from time to time to extend the Expiration Date in the
manner described above.
 
    To be effective, a written notice of withdrawal must be timely received by
the Exchange Agent at the address set out on the back cover page of this
Prospectus and must specify the name of the Person who has tendered the
Unionamerica ADSs to be withdrawn, the number of Unionamerica ADSs to be
withdrawn and (if Unionamerica ADRs have been tendered) the name of the
registered holder of the Unionamerica ADSs, if different from the name of the
person who tendered the Unionamerica ADSs.
 
    In respect of Unionamerica ADSs, if Unionamerica ADRs have been delivered or
otherwise identified to the Exchange Agent, then, prior to the physical release
of such Unionamerica ADRs, the serial numbers shown on such Unionamerica ADRs
must be submitted and, unless the Unionamerica ADSs evidenced by such
Unionamerica ADRs have been tendered by an Eligible Institution or by means of a
Letter of Transmittal, the signatures on the notice of withdrawal must be
guaranteed by an Eligible Institution. If Unionamerica ADSs have been delivered
pursuant to the procedures for book-entry transfer set out in "Procedures for
Tendering Unionamerica ADSs", any notice of withdrawal must also specify the
name and number of the account at the appropriate Book-Entry Transfer Facility
to be credited with the withdrawn Unionamerica ADSs and must otherwise comply
with such Book-Entry Transfer Facility's procedures.
 
                                       34
<PAGE>
    Withdrawals of tendered Unionamerica Securities may not be rescinded
(without MMI's consent), and any Unionamerica Securities properly withdrawn will
thereafter be deemed not validly tendered for the purposes of the Offer.
Withdrawn Unionamerica Securities may be subsequently retendered, however, by
following one of the procedures described above in "--Procedures for Tendering
Unionamerica ADSs", at any time prior to the Expiration Date, including any
extension thereof.
 
    All questions as to the validity (including time of receipt) of any notice
of withdrawal will be determined by MMI, whose determination (except as required
by the Panel) will be final and binding. None of MMI, Unionamerica, the Exchange
Agent, the Dealer Manager or any other Person will be under any duty to give
notification of any defects or irregularities in any notice of withdrawal or
incur any liability for failure to give any such notification.
 
EXTENSIONS; AMENDMENTS; AND TERMINATION
 
    Subject to the provisions of the Acquisition Agreement, MMI expressly
reserves the right (but will not be obligated) at any time or from time to time
to extend the Expiration Date and, in such event, will make a public
announcement of such extension in the manner described under "--Announcements"
below and give oral or written notice of such extension to the Exchange Agent.
If all the Conditions have not been satisfied or, where permitted, waived by MMI
by the Expiration Date, MMI currently intends to extend the Expiration Date
until such time as the Conditions have been satisfied or, where permitted,
waived. There can be no assurance, however, that MMI will, in such
circumstances, extend the Expiration Date and if no such extension is made, the
Offer will lapse on the Expiration Date and no Unionamerica Securities will be
exchanged pursuant to the Offer. If all the Conditions have not been satisfied
or, where permitted, waived prior to 12 midnight, New York City time, on the
date being 60 calendar days from the date of commencement of the Offer, or such
later date as the Panel may determine, in the absence of a competitive situation
and/or unless the Panel otherwise agrees, the Offer will lapse. If the Offer was
to lapse, pursuant to the City Code neither MMI nor any Person acting or deemed
to be acting in concert with MMI for the purpose of the Offer nor any of their
respective affiliates could make an offer (whether in or outside the U.K.) for
Unionamerica Securities for a period of one year following the date of such
lapse, except with the prior permission of the Panel.
 
    The acceptance by or on behalf of a previous acceptor of the Offer in its
original or any previously revised form(s) shall, subject as provided in this
paragraph and subject to the withdrawal rights of such acceptor as described
under "--Withdrawal Rights", be deemed an acceptance of the Offer as revised and
shall constitute an authority to MMI or its agents as his or her attorney to
accept any such revised Offer on behalf of such previous acceptor and, if such
revised Offer includes alternative forms of consideration, to make elections
for, and/or accept, alternative forms of consideration on his or her behalf as
such attorney may in his or her absolute discretion think fit, and to execute on
behalf of and in the name of such previous acceptor all such further documents
(if any) as may be required to give effect to such acceptances and/or elections.
In making any such elections and/or acceptances, such attorney shall take into
account the nature of any original acceptance made by the previous acceptor and
such other facts or matters as he or she may reasonably consider relevant. The
deemed acceptances and/or elections referred to in this paragraph shall not
apply and the authority and powers of attorney referred to shall not be
exercised by MMI or any of its agents if, as a result thereof, the previous
acceptor would (on such basis as MMI may consider appropriate) thereby receive
less in aggregate in consideration than he or she would have received in
aggregate in consideration as a result of any previous acceptance of the Offer
(or any previous revision thereof), unless such previous acceptor has previously
agreed in writing to receive less in aggregate consideration. The powers of
attorney and authority referred to in this paragraph and any acceptance of the
revised Offer shall be irrevocable until the previous acceptor properly
withdraws his or her acceptance as described under "--Withdrawal Rights". MMI
reserves the right to treat as valid any executed Letter of Transmittal relating
to the Offer (in its original or any previously revised form(s)) which is
received after the announcement or issue of the Offer in any revised form as a
valid acceptance of the Offer, as revised,
 
                                       35
<PAGE>
and such acceptance shall constitute authority in terms of this paragraph on
behalf of the relevant Unionamerica Securityholder. The deemed acceptances and
elections referred to in this paragraph shall not apply and the power of
attorney and authorities conferred by this paragraph shall be ineffective to the
extent that a previous acceptor lodges, within ten business days of the posting
of the document pursuant to which the revision of the Offer referred to in this
paragraph is made available to Unionamerica Securityholders, a Letter of
Transmittal in which he or she validly elects to receive the consideration
receivable by him or her under the revised Offer in some other manner.
 
    MMI confirms that if it makes a material change in the terms of the Offer or
the information concerning the Offer, or if it waives a material condition of
the Offer, MMI will extend the Offer to the extent required under the Exchange
Act, which shall be a minimum of five business days from the date that the
material change is first published, sent or given to Unionamerica
Securityholders. If, prior to the Expiration Date, including any extension
thereof, MMI shall increase or decrease the percentage of Unionamerica ADSs
being sought or the consideration offered to Unionamerica Securityholders, such
increase or decrease shall be applicable to all Unionamerica Securityholders
whose ADSs are accepted for exchange pursuant to the Offer, and if at the time
notice of any such increase or decrease is first published, sent or given to
Unionamerica Securityholders, the Offer is scheduled to expire at any time
earlier than the tenth business day from and including the date that such notice
is first so published, sent or given, the Offer will be extended until the
expiration of such ten business day period.
 
    If all the Conditions are not satisfied or, where permitted, waived at the
Expiration Date, including any extension thereof, the Offer will, unless the
Panel otherwise agrees, lapse and all Unionamerica Securities previously
tendered and not validly withdrawn will be returned. MMI expressly reserves the
right (a) not to extend the Expiration Date if all the Conditions are not
satisfied or, where permitted, waived on the Expiration Date and to terminate
the Offer (in which event all Unionamerica Securities for which acceptances have
been received will be returned), and (b) at any time on or after the Expiration
Date, if all Conditions are not satisfied or, where permitted, waived, to
terminate the Offer and not accept any Unionamerica Securities not tendered on
or before that date and, in such event, will give oral or written notice of such
termination to the Exchange Agent and make a public announcement in the manner
provided below under "--Announcements".
 
    If a competitive situation arises after a "no increase" and/or a "no
extension" statement has been made in relation to the Offer, MMI may if it
specifically reserves the right to do so at the time such statement is made, or
otherwise with the consent of the Panel, withdraw such statement and be free to
revise or increase the Offer if it announces such withdrawal within four
business days after the announcement of the competing offer and notifies
Unionamerica Securityholders to that effect in writing at the earliest
opportunity thereafter. MMI may choose not to be bound by the terms of a "no
increase" and/or "no extension" statement if, having reserved the right to do so
at the time such statement is made, it posts an increased or improved offer
which is recommended for acceptance by the Unionamerica Board or in any other
circumstances permitted by the Panel.
 
    CERTAIN CONSEQUENCES OF THE OFFER.  The purchase of Unionamerica ADSs
pursuant to the Offer will reduce the number of Unionamerica Securityholders and
the number of Unionamerica ADSs that might otherwise trade publicly and,
depending on the number of Unionamerica ADSs so purchased, could adversely
affect the liquidity and market value of the remaining Unionamerica ADSs held by
the public. In addition, Unionamerica ADSs will cease to be quoted on the NYSE
if MMI is entitled to and does effect the Compulsory Acquisition. Even if the
Compulsory Acquisition is not effected, there would be a delisting from the NYSE
if certain minimum requirements with respect to the number of publicly held
shares and/or the number of public shareholders or other criteria are not met.
The Unionamerica ADSs may also be
 
                                       36
<PAGE>
deregistered under the Exchange Act if minimum requirements with respect to the
number of shareholders of record are not met, with a consequent termination of
certain public reporting obligations in the U.S.
 
    DELIVERY OF CONSIDERATION.  Subject to the Offer becoming or being declared
unconditional in all respects, share certificates in respect of MMI Common Stock
in settlement of the consideration due under the Offer will be dispatched by
first class post to accepting Unionamerica Securityholders or their appointed
agents at their own risk: (i) in the case of acceptances received, complete and
in order in all respects by the date on which the Offer becomes or is declared
unconditional in all respects, within 14 calendar days of such date; or (ii) in
the case of acceptances received, complete and in order in all respects after
such date but while the Offer remains open for acceptance, within 14 calendar
days of such receipt.
 
    Except with the consent of the Panel, settlement of the consideration due
under the Offer will be made in full in accordance with the terms of the Offer
without regard to any lien, right of set-off, counterclaim or other analogous
right to which MMI may otherwise be, or claim to be, entitled as against a
Unionamerica Securityholder.
 
    UNIONAMERICA SECURITYHOLDERS RESIDENT OUTSIDE THE U.S. OR THE U.K.  The
Offer is being made to all Unionamerica Securityholders; provided, however, the
receipt of this Prospectus does not constitute the making of the Offer to (and
tenders of Unionamerica Securities will not be accepted from or on behalf of)
Unionamerica Securityholders in any jurisdiction in the U.S. in which the making
of the Offer or the acceptance thereof would not be in compliance with the laws
of such jurisdiction. MMI is not currently aware of any jurisdiction in the U.S.
that prohibits the making of the Offer. MMI may, in its discretion, take such
action as it may deem necessary to make the Offer in any such jurisdiction and
extend the Offer to Unionamerica Securityholders in such jurisdictions.
 
    The making of the Offer in, or to Persons resident in or citizens or
nationals of, jurisdictions outside the U.S. or the U.K. may be affected by the
laws of such jurisdictions. Unionamerica Securityholders not resident in the
U.S. or the U.K. should inform themselves about and observe any applicable legal
requirements. It is the responsibility of any Person outside the U.S. or U.K.
wishing to accept the Offer to satisfy himself or herself as to the full
observance of the laws of the relevant jurisdiction in connection therewith,
including the obtaining of any governmental or other consents which may be
required, the compliance with other necessary formalities and the payment of any
taxes or other requisite payments due in such jurisdiction.
 
    The Offer extends to any Unionamerica Securityholders not resident in the
U.K. to whom this Prospectus, the Letter of Transmittal and any related
documents may not be dispatched and such Unionamerica Securityholders may
collect copies of those documents from the Exchange Agent or the Dealer Manager
at the addresses set out on the back cover page of this Prospectus.
 
    ANNOUNCEMENTS.  Any termination, revision, variation, extension or renewal
of the Offer or extension of the Expiration Date will be followed as promptly as
practicable by public announcements thereof no later than 8:30 a.m. (London
time) in the U.K. and 8:30 a.m. (New York City time) in the U.S., on the
business day following the day of such termination, revision, variation,
extension or renewal (or such later time and/or date as the Panel may agree).
Announcements will also be made no later than 8:30 a.m. (London time) in the
U.K. and 8:30 a.m. (New York City time) in the U.S. on the business day
following the Expiration Date. Without limiting the manner in which MMI may
choose to make any public announcement and subject to MMI's obligations under
applicable law (including Rules 14d-4(c) and 14d-6(d) under the Exchange Act
relating to MMI's obligation to disseminate promptly public announcements
concerning material changes to the Offer), MMI will have no obligation to
publish, advertise or otherwise communicate any such public announcement other
than by making a release to the Dow Jones News Service and the NYSE. Such
announcement will also state (as nearly as practicable) the total number of
Unionamerica Securities (i) for which acceptances of the Offer have been
received and not validly
 
                                       37
<PAGE>
withdrawn, (ii) acquired or agreed to be acquired by or on behalf of MMI or any
person deemed to be acting in concert (determined in accordance with the City
Code) with it during the offer period as such expression is defined in the City
Code, (iii) held by or on behalf of MMI or any Persons deemed to be acting in
concert with it prior to June 25, 1997 and (iv) for which acceptances of the
Offer have been received from any Person deemed to be acting in concert with
MMI. The announcement will also specify the percentage of the Unionamerica
Securities represented by each of these figures. The announcement of an
extension will state the time and date to which the Expiration Date has been
extended. In computing the number of Unionamerica Securities represented by
acceptances and/or tenders, there may be included or excluded for announcement
purposes, subject to the City Code, acceptances and tenders not in all respects
in order or subject to verification.
 
    References to the making of an announcement by MMI include the release of an
announcement by public relations consultants or MMI to the press and delivery by
telephone or facsimile transmission of such announcement to the Dow Jones News
Service and the NYSE.
 
    PUBLICATION; NOTIFICATION; GENERAL INFORMATION.  The Offer will be made by
means of this Prospectus and the Letter of Transmittal and may be accepted from
and after that time.
 
    MMI and the Exchange Agent reserve the right to send notices regarding any
matter, including the making of the Offer, to a Unionamerica Securityholder:
 
    1.  with a registered address outside the U.K. or the U.S.; or
 
    2.  whom MMI knows to be a custodian, trustee or nominee holding
Unionamerica ADSs for Persons who are citizens, residents or nationals of
jurisdictions outside the U.K or the U.S.,
 
by announcement or by paid advertisement in a newspaper published and circulated
in the U.K. or the U.S. The notice will be deemed to have been sufficiently
given, despite any failure by a Unionamerica Securityholder to receive or see
that notice. A reference in this Prospectus to a notice or the provision of
information in writing by or on behalf of MMI is to be construed accordingly.
 
    The Unionamerica Securities which are the subject of the Offer will be
acquired free from all liens, charges, restrictions (including restrictions
imposed by law), third party rights and encumbrances and will be acquired with
all rights now or hereafter attaching thereto, including voting rights and the
right to all dividends and other distributions declared, made or paid hereafter,
other than any regular quarterly dividend of $0.0125 per share of Unionamerica
Common Stock to be paid on or prior to the date on which the Offer becomes or is
declared unconditional in all respects, or the Expiration Date, including any
extension thereof, whichever is later.
 
    If the Offer lapses or is withdrawn, the Letters of Transmittal, ADRs and
all document(s) of title will be returned by posting the same promptly
thereafter to the Person or agent whose name and address is set out in the
appropriate box on the Letter of Transmittal or, if none is set out, to the
first-named holder at his registered address.
 
    All documents and remittances sent by, to or from Unionamerica
Securityholders or their appointed agents will be sent at their own risk.
 
    Neither MMI nor its agents nor any other Person acting on behalf of it or
them shall have any liability to any Person for any loss or alleged loss arising
from the price, timing or manner of any exchange made pursuant to the authority
set out above or otherwise in connection therewith.
 
    THE OFFER AND ALL CONTRACTS ARISING FROM ACCEPTANCES OF, OR PURSUANT TO, IT
AND THE LETTERS OF TRANSMITTAL (OTHER THAN IN RELATION TO THE COMPULSORY
ACQUISITION WHICH SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
ENGLISH LAW) SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF DELAWARE.
 
                                       38
<PAGE>
    Execution and delivery by or on behalf of a Unionamerica Securityholder of a
Letter of Transmittal constitutes such Person's: (i) irrevocable submission, in
relation to all matters arising out of the Offer and the Letter of Transmittal,
to the jurisdiction of the courts of England and (ii) agreement that nothing
shall limit the right of MMI to bring any action, suit or proceeding arising out
of or in connection with the Offer in any manner permitted by law and in any
competent court of jurisdiction. The conduct of the Offer is, however, also
subject to the U.S. federal securities laws and the securities laws of the
states of the U.S. in which the Offer is being made. All references in this
Prospectus to any statute or statutory provision shall include any statute or
statutory provision which amends, consolidates or replaces the same. This
Prospectus is issued by MMI.
 
MMI'S REASONS FOR THE PROPOSED ACQUISITION AND RECOMMENDATION OF THE MMI BOARD
 
    MMI believes that its target market, the healthcare industry, is undergoing
structural change and organizational consolidation. MMI further believes that
the medical malpractice industry is also undergoing consolidation, in part in
response to the dynamics of its target market. MMI believes that current market
conditions favor larger, strongly capitalized companies with multiple licenses,
broad distribution systems and a full complement of insurance and risk
management products and services. Consequently a key element of MMI's business
strategy has been to seek growth through acquisition in order to achieve these
objectives.
 
    MMI believes that the acquisition of Unionamerica offers MMI an opportunity
to improve its competitive position. A substantial portion of Unionamerica's
business involves operating as a reinsurer of medical malpractice insurance
companies throughout the U.S. This distribution system affords MMI an
opportunity to substantially increase its medical malpractice assumed
reinsurance premium writings by virtue of the Proposed Acquisition and to form
and expand upon strategic business relationships with direct writers of medical
malpractice insurance. Although MMI intends to continue to operate Unionamerica
as a distinct business entity under its present management and business plans,
the combined capitalization of the combined entities would be among the largest
of specialty medical malpractice writers.
 
    The medical malpractice business environment is currently in a prolonged
soft market, where competitive pricing pressures have reduced the opportunity
for MMI to obtain rate increases and thereby revenue growth. Unionamerica's
business plan includes prospects for premium growth in areas outside of the
medical malpractice line of business, including both U.S. property and casualty
lines and London market and European property and casualty lines, and MMI
believes that Unionamerica's management has the background and experience to
manage such growth profitably.
 
    Material factors considered by the MMI Board in its evaluation of the
acquisition of Unionamerica included the following: (i) Unionamerica's core line
of business, professional indemnity reinsurance, is complementary to MMI's
principal line of business, medical malpractice insurance; approximately 27% of
Unionamerica's gross premiums written are derived from reinsurance of U.S.
medical malpractice insurance companies; (ii) Unionamerica has a strong
historical record of underwriting profit and return on equity and strong
prospects for revenue and earnings growth; (iii) Unionamerica has strong growth
prospects in international medical malpractice and non-professional liability
markets that provide opportunity for earnings growth and geographical and line
of business diversification of underwriting exposure; (iv) Unionamerica has a
management group with substantial depth and reinsurance and London market
experience; (v) Unionamerica's ADSs have historically traded at a discount to
comparable companies in part due to liquidity issues; (vi) MMI expects to obtain
operating synergies and expense reductions of up to $1 million annually (by
eliminating certain functional redundancies) by virtue of Unionamerica ceasing
to be a separate public entity and becoming a wholly-owned Subsidiary of MMI;
(vii) the impact of an increase in shares outstanding may serve to improve
trading liquidity of MMI Common Stock, thereby improving shareholder value; and
(viii) the opinion rendered to the MMI Board by Smith Barney with regard to the
fairness of the Exchange Ratio, from a financial point of view, to MMI.
 
                                       39
<PAGE>
    The MMI Board considered each of the factors listed above to be beneficial
to the MMI stockholders. Based on this analysis, the MMI Board determined that
the Proposed Acquisition is fair to, and in the best interests of, the MMI
stockholders. The foregoing discussion of the information and factors considered
by the MMI Board is not intended to be exhaustive, and were considered
collectively by the MMI Board in connection with its review of the Acquisition
Agreement. The decision of the MMI Board to approve the Acquisition Agreement
and the transactions contemplated thereby was based on its consideration of many
factors, including those noted above, taken as a whole. The MMI Board did not
analyze specific factors in isolation. In view of the variety of factors
considered in connection with its evaluation of the Proposed Acquisition, the
MMI Board did not find it practicable to, and did not, quantify or otherwise
assign relative weights to the specific factors considered in reaching its
determination. In addition, individual members of the MMI Board may have given
different weights to different factors. For a discussion of the interests of
MMI's directors and executive officers in MMI, see "Prospectus Summary--MMI
Common Stock and Unionamerica ADSs Held by Directors, Executive Officers and
Their Affiliates".
 
    The MMI Board also considered specific risk factors in connection with the
Proposed Acquisition. Such risk factors included the following: (i) the value of
the consideration given for each Unionamerica ADS may vary due to the fixed
exchange ratio; (ii) operating synergies may not, or may be slow to,
materialize; (iii) MMI or Unionamerica may experience loss of personnel or
customers; (iv) industry factors, including competition and insurance capacity
could negatively impact future results; (v) reserves for losses and loss
adjustment expenses are based on estimates and may prove inaccurate; and (vi)
operating results may be negatively impacted if the Proposed Acquisition were to
fail to qualify for pooling-of-interests accounting treatment. While the MMI
Board recommends that the issuance of shares of MMI Common Stock in connection
with the Proposed Acquisition be approved, the Board also is aware that the risk
factors described above exist. If certain of the events described in such risk
factors were to occur, the presently perceived benefits of the transaction to
the MMI stockholders and Unionamerica Securityholders might be diminished, or
such occurences may impact negatively upon the combined operations of MMI and
Unionamerica.
 
    THE MMI BOARD BELIEVES THAT THE TERMS OF THE ACQUISITION AGREEMENT AND THE
TRANSACTIONS CONTEMPLATED THEREBY ARE FAIR TO, AND IN THE BEST INTERESTS OF MMI
AND ITS STOCKHOLDERS. ACCORDINGLY, AT ITS JUNE 24, 1997 MEETING, THE MMI BOARD
APPROVED THE ACQUISITION AGREEMENT AND THE TRANSACTIONS CONTEMPLATED THEREBY AND
HEREBY RECOMMENDS THAT HOLDERS OF MMI COMMON STOCK VOTE FOR APPROVAL OF THE
ISSUANCE OF SHARES OF MMI COMMON STOCK IN CONNECTION WITH THE PROPOSED
ACQUISITION.
 
OPINION OF FINANCIAL ADVISOR TO MMI
 
    SMITH BARNEY.  Smith Barney was retained by MMI to act as its financial
advisor in connection with the Proposed Acquisition. In connection with such
engagement, MMI requested that Smith Barney evaluate the fairness, from a
financial point of view, to MMI of the consideration proposed to be paid by MMI
pursuant to the terms of the Acquisition Agreement. On June 24, 1997, at a
meeting of the MMI Board held to evaluate the Proposed Acquisition, Smith Barney
delivered an oral opinion (subsequently confirmed by delivery of a written
opinion dated June 24, 1997) to the MMI Board to the effect that, as of the date
of such opinion and based upon and subject to certain matters stated therein,
the Exchange Ratio was fair, from a financial point of view, to MMI.
 
    In arriving at its opinion, Smith Barney reviewed a draft of the Acquisition
Agreement and held discussions with certain senior officers, directors and other
representatives and advisors of MMI and certain senior officers and other
representatives and advisors of Unionamerica concerning the businesses,
operations and prospects of MMI and Unionamerica. Smith Barney examined certain
publicly available business and financial information relating to MMI and
Unionamerica as well as certain financial forecasts and other information and
data for MMI and Unionamerica which were provided to, or otherwise
 
                                       40
<PAGE>
discussed with, Smith Barney by the respective managements of MMI and
Unionamerica, including information relating to certain strategic implications
and operational benefits anticipated to result from the Proposed Acquisition.
Smith Barney reviewed the financial terms of the Proposed Acquisition as set
forth in the Acquisition Agreement in relation to, among other things (i)
current and historical market prices and trading volumes of MMI Common Stock and
Unionamerica ADSs; (ii) the historical and projected earnings and other
operating data of MMI and Unionamerica; and (iii) the capitalization and
financial condition of MMI and Unionamerica. Smith Barney also considered, to
the extent publicly available, the financial terms of certain other similar
transactions recently effected which Smith Barney considered relevant in
evaluating the Proposed Acquisition and analyzed certain financial, stock market
and other publicly available information relating to the businesses of other
companies whose operations Smith Barney considered relevant in evaluating those
of MMI and Unionamerica. Smith Barney also evaluated the potential pro forma
financial impact of the Proposed Acquisition on MMI. In addition to the
foregoing, Smith Barney conducted such other analyses and examinations and
considered such other financial, economic and market criteria as Smith Barney
deemed appropriate in arriving at its opinion. Smith Barney noted that its
opinion was necessarily based upon information available, and financial, stock
market and other conditions and circumstances existing and disclosed to Smith
Barney as of the date of its opinion.
 
    In rendering its opinion, Smith Barney assumed and relied, without
independent verification, upon the accuracy and completeness of all financial
and other information and data publicly available or furnished to or otherwise
reviewed by or discussed with Smith Barney. Smith Barney also assumed, with the
consent of the MMI Board, that the final terms of the Acquisition Agreement
reviewed by Smith Barney in draft form would not vary materially from the draft
reviewed by Smith Barney. With respect to financial forecasts and other
information and data furnished to or otherwise reviewed by or discussed with
Smith Barney, the managements of MMI and Unionamerica advised Smith Barney that
such forecasts and other information and data were reasonably prepared on bases
reflecting the best currently available estimates and judgments of the
respective managements of MMI and Unionamerica as to the future financial
performance of MMI and Unionamerica and the strategic implications and
operational benefits anticipated to result from the Proposed Acquisition. Smith
Barney assumed, with the consent of the MMI Board, that the Proposed Acquisition
will be treated as a pooling-of-interests in accordance with GAAP and as a
tax-free reorganization for U.S. federal income tax purposes. Smith Barney's
opinion, as set forth therein, relates to the relative values of MMI and
Unionamerica. Smith Barney did not express any opinion as to what the value of
the MMI Common Stock actually will be when issued pursuant to the Offer or the
price at which the MMI Common Stock will trade subsequent to the consummation of
the Proposed Acquisition. Smith Barney did not make and, with the exception of
certain reserve reports relating to Unionamerica, was not provided with an
independent evaluation or appraisal of the assets, liabilities (contingent or
otherwise) or reserves of MMI or Unionamerica nor did Smith Barney make any
physical inspection of the properties or assets of MMI or Unionamerica. Smith
Barney was not requested to consider, and Smith Barney's opinion does not
address, the relative merits of the Proposed Acquisition as compared to any
alternative business strategies that might exist for MMI or the effect of any
other transaction in which MMI might engage. Although Smith Barney evaluated the
Exchange Ratio from a financial point of view, Smith Barney was not asked to and
did not recommend the specific consideration payable in the Proposed
Acquisition, which was determined through negotiation between MMI and
Unionamerica. No other limitations were imposed by MMI on Smith Barney with
respect to the investigations made or procedures followed by Smith Barney in
rendering its opinion.
 
    In preparing its opinion to the MMI Board, Smith Barney performed a variety
of financial and comparative analyses, including those described below performed
by Smith Barney in connection with its opinion dated June 24, 1997. The summary
of such analyses does not purport to be a complete description of the analyses
underlying Smith Barney's opinion. The preparation of a financial opinion is a
complex analytic process involving various determinations as to the most
appropriate and relevant methods of financial analyses and the application of
those methods to the particular circumstances and, therefore, such
 
                                       41
<PAGE>
an opinion is not readily susceptible to summary description. Smith Barney
believes that its analyses must be considered as a whole and that selecting
portions of its analyses and factors, without considering all analyses and
factors, could create a misleading or incomplete view of the processes
underlying such analyses and its opinion. In its analyses, Smith Barney made
numerous assumptions with respect to MMI, Unionamerica, industry performance,
general business, economic, market and financial conditions and other matters,
many of which are beyond the control of MMI and Unionamerica. The estimates
contained in such analyses and the valuation ranges resulting from any
particular analysis are not necessarily indicative of actual values or
predictive of future results or values, which may be significantly more or less
favorable than those suggested by such analyses. In addition, analyses relating
to the value of businesses or securities do not purport to be appraisals or to
reflect the prices at which businesses or securities actually may be sold.
Accordingly, such analyses and estimates are inherently subject to substantial
uncertainty. Smith Barney's opinion and financial analyses were only one of many
factors considered by the MMI Board in its evaluation of the Proposed
Acquisition and should not be viewed as determinative of the views of the MMI
Board or management with respect to the Exchange Ratio or the Proposed
Acquisition.
 
    The following is a summary of the material financial analyses performed by
Smith Barney in connection with its written opinion dated June 24, 1997:
 
    SELECTED COMPANY ANALYSIS.  Using publicly available information, Smith
Barney analyzed, among other things, the market values and trading multiples of
MMI, Unionamerica and seven selected publicly traded companies in the insurance
and reinsurance industry, consisting of: SCPIE Holdings, Inc., MAIC Holdings
Inc., FPIC Insurance Group, Inc., NAC Re Corp., Terra Nova (Bermuda) Holdings
Ltd., Trenwick Group Inc. and Chartwell Re Corporation (collectively, the
"Selected Companies"). Smith Barney compared, among other things, market values
of the Selected Companies as multiples of, among other things, estimated
calendar 1997 and calendar 1998 net operating income computed in accordance with
GAAP, and GAAP book value as of March 31, 1997. Smith Barney also compared the
relationship between the price to book value multiples and projected return on
average equity ("ROE") of the Selected Companies with that of Unionamerica. Net
income projections for the Selected Companies were based on estimates of
selected investment banking firms and net income projections for MMI and
Unionamerica were based on internal estimates of the managements of MMI and
Unionamerica. All multiples were based on closing stock prices as of June 11,
1997. Applying a range of selected multiples for the Selected Companies of
estimated calendar 1997 and 1998 GAAP net operating income and estimated GAAP
book value as of March 31, 1997, of 9.1x to 11.7x, 8.3x to 10.5x and 1.31x to
1.69x, respectively, to corresponding financial data of Unionamerica resulted in
equity reference ranges for Unionamerica of approximately $18.66 to $23.76 per
share (on a fully diluted basis). Based on the relationship of the price to book
value multiples and projected ROE of the Selected Companies, the implied equity
value for Unionamerica was approximately $22.05 per share on a fully diluted
basis. Based on a closing stock price of MMI Common Stock on June 24, 1997, the
Exchange Ratio equated to an implied equity value for Unionamerica of
approximately $22.15 per share.
 
    SELECTED MERGER AND ACQUISITION TRANSACTIONS ANALYSIS.  Using publicly
available information, Smith Barney analyzed the purchase price and implied
transaction multiples paid in nine selected transactions in the insurance and
reinsurance industry consisting of (target/acquiror): SAFR/PartnerRe Ltd.,
Zurich Reinsurance Centre Holdings, Inc./Zurich Insurance Company, Piedmont
Management Company, Inc./ Chartwell Re Corporation, Discover Re Managers,
Inc./USF&G Corporation, Re Capital Corporation/ Zurich Reinsurance Centre
Holdings, Inc., Underwriters Reinsurance Corp./Alleghany Corporation, American
Re Corporation/Kohlberg Kravis Roberts & Co., Chartwell Re Corporation/Wand
Partners Inc. and National Re Corp./National Re Holdings Corp. (collectively,
the "Selected Transactions"). Smith Barney compared the purchase prices in such
transactions as multiples of, among other things, last twelve month GAAP net
income ("LTM GAAP net income"), one-year forward GAAP net income and March 31,
1997 book value. All multiples for the Selected Transactions were based on
information available at the time of announcement of the transaction. Applying a
range of selected multiples for the
 
                                       42
<PAGE>
Selected Transactions of LTM GAAP net income, one-year forward GAAP net income
and March 31, 1997 book value of 9.5x to 12.5x, 10.6x to 13.9x and 1.27x to
1.70x, respectively, to corresponding financial data for Unionamerica resulted
in an average equity reference range for Unionamerica of approximately $17.12 to
$22.55 per share on a fully diluted basis, as compared to the equity value
implied by the Exchange Ratio of approximately $22.15 per share based on a
closing price of MMI Common Stock on June 24, 1997.
 
    No company, transaction or business used as a comparison in the "Selected
Company Analysis" or "Selected Merger and Acquisition Transactions Analysis" is
identical to MMI, Unionamerica or the Proposed Acquisition. Accordingly, an
analysis of the results of the foregoing is not entirely mathematical; rather,
it involves complex considerations and judgments concerning differences in
financial and operating characteristics and other factors that could affect the
acquisition, public trading or other values of the Selected Companies, Selected
Transactions or the business segment, company or transaction to which they are
being compared.
 
    DISCOUNTED CASH FLOW ANALYSIS.  Smith Barney performed a discounted cash
flow analysis of the projected dividendable net income of Unionamerica for
fiscal years 1997 through 2001, based on internal estimates of the management of
MMI and Unionamerica. The range of the estimated terminal value for Unionamerica
at the end of the five-year period was calculated by applying terminal multiples
ranging from 9.0x to 13.0x to Unionamerica's projected 2002 net income,
representing Unionamerica's estimated value at June 30, 2000. The net income
terminal value of Unionamerica was discounted to June 30, 1997 using rates
ranging from 9% to 14%. This analysis resulted in an equity reference range for
Unionamerica of approximately $16.03 to $22.01 per share, as compared to the
equity value implied by the Exchange Ratio of approximately $22.15 per share
based on a closing price of MMI Common Stock on June 24, 1997.
 
    PRO FORMA MERGER ANALYSIS.  Smith Barney analyzed certain pro forma effects
resulting from the Proposed Acquisition, including, among other things, the
impact of the Proposed Acquisition on the projected earnings per share ("EPS")
of MMI for the fiscal years ending 1997 and 1998, based on internal estimates of
the management of MMI and internal estimates of the management of Unionamerica.
The results of the pro forma merger analysis suggested that the Offer could be
accretive to MMI's EPS in each of the fiscal years analyzed. The actual results
achieved by the combined company may vary from projected results and the
variations may be material.
 
    OTHER FACTORS AND COMPARATIVE ANALYSES.  In rendering its opinion, Smith
Barney considered certain other factors and conducted certain other comparative
analyses, including, among other things, a review of (i) the historical and
projected financial results of MMI and Unionamerica; (ii) the history of trading
prices and volume for Unionamerica ADSs and the relationship between movements
of such securities with that of the MMI Common Stock; (iii) premiums paid in
selected stock-for-stock transactions in the insurance and reinsurance industry;
and (iv) the pro forma ownership of the combined company. In addition, Smith
Barney analyzed the respective contributions of MMI and Unionamerica to the net
premiums written and net operating income of the combined company for fiscal
year 1996.
 
    Pursuant to the terms of Smith Barney's engagement, MMI has agreed to pay
Smith Barney for its services in connection with the Proposed Acquisition an
aggregate financial advisory fee of $1.672 million, a substantial portion of
which is payable only if the Proposed Acquisition is consummated. MMI has also
agreed to reimburse Smith Barney for reasonable travel and other reasonable
out-of-pocket expenses incurred by Smith Barney in performing its services,
including the reasonable fees and expenses of its legal counsel, and to
indemnify Smith Barney and related Persons against certain liabilities,
including liabilities under the federal securities laws, arising out of Smith
Barney's engagement.
 
    Smith Barney has advised MMI that, in the ordinary course of business, Smith
Barney and its affiliates may actively trade or hold the securities of MMI and
Unionamerica for their own account or for the account of customers and,
accordingly, may at any time hold a long or short position in such securities.
Smith Barney has in the past provided certain investment banking services to MMI
unrelated to the
 
                                       43
<PAGE>
Proposed Acquisition, including serving as a managing underwriter in the initial
public offering of MMI Common Stock in June 1993 and the subsequent public
offering of MMI Common Stock in September 1996, for which services Smith Barney
has received compensation. In addition, Smith Barney and its affiliates
(including Travelers Group Inc. and its affiliates) may maintain relationships
with MMI and Unionamerica.
 
    Smith Barney is a nationally recognized investment banking firm and was
selected by MMI based on Smith Barney's experience, expertise and familiarity
with MMI and its business. Smith Barney regularly engages in the valuation of
businesses and their securities in connection with mergers and acquisitions,
negotiated underwritings, competitive bids, secondary distributions of listed
and unlisted securities, private placements and valuations for estate, corporate
and other purposes.
 
    THE FULL TEXT OF THE WRITTEN OPINION OF SMITH BARNEY DATED JUNE 24, 1997,
WHICH SETS FORTH THE ASSUMPTIONS MADE, MATTERS CONSIDERED AND LIMITATIONS ON THE
REVIEW UNDERTAKEN, IS ATTACHED HERETO AS APPENDIX B AND IS INCORPORATED HEREIN
BY REFERENCE. SMITH BARNEY HAS CONSENTED TO THE USE OF ITS OPINION IN THIS
PROSPECTUS. HOLDERS OF MMI COMMON STOCK ARE URGED TO READ THIS OPINION CAREFULLY
IN ITS ENTIRETY. SMITH BARNEY'S OPINION IS DIRECTED TO THE MMI BOARD AND RELATES
ONLY TO THE FAIRNESS OF THE EXCHANGE RATIO FROM A FINANCIAL POINT OF VIEW TO
MMI, DOES NOT ADDRESS ANY OTHER ASPECT OF THE OFFER OR RELATED TRANSACTIONS AND
DOES NOT CONSTITUTE A RECOMMENDATION TO ANY STOCKHOLDER AS TO HOW SUCH
STOCKHOLDER SHOULD VOTE AT THE MMI SPECIAL MEETING OR AS TO WHETHER ANY
UNIONAMERICA SECURITYHOLDER SHOULD ACCEPT THE OFFER. THE SUMMARY OF THE OPINION
OF SMITH BARNEY SET FORTH IN THIS PROSPECTUS IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO THE FULL TEXT OF SUCH OPINION.
 
UNIONAMERICA'S REASONS FOR THE PROPOSED ACQUISITION AND RECOMMENDATION OF THE
  UNIONAMERICA BOARD
 
    The Unionamerica Board has unanimously approved the Acquisition Agreement
and the transactions contemplated thereby. In reaching its conclusion to approve
the Acquisition Agreement, the Unionamerica Board considered many factors,
including, but not limited to, the following material factors:
 
        (i) the terms and conditions of the Offer and the Acquisition Agreement,
    including the amount and form of consideration to be received by
    Unionamerica Securityholders in the Offer, the tax representations,
    warranties and covenants in the Acquisition Agreement, the conditions to the
    Offer that the MMI Common Stock to be exchanged for Unionamerica ADSs in the
    Offer be registered under the Securities Act and listed on the NYSE and the
    premium which Unionamerica Securityholders would receive based upon the
    Exchange Ratio and the market prices for MMI Common Stock and Unionamerica
    ADSs prior to June 25, 1997;
 
        (ii) the Unionamerica Board's familiarity with, among other things, the
    business, operations, financial condition, competitive position and
    prospects of Unionamerica, the nature of the reinsurance industry in which
    Unionamerica participates, and current industry, economic and market
    conditions, both on a historical and on a prospective basis;
 
       (iii) the Unionamerica Board's review of the historical and prospective
    market prices of the Unionamerica ADSs compared to the Exchange Ratio. The
    market prices of Unionamerica ADSs and MMI Common Stock as of June 23, 1997,
    the last trading day preceding the Unionamerica Board's meeting to consider
    the Acquisition Agreement, were $19.00 and $26.00, respectively. Based on
    the Exchange Ratio, the Offer valued each Unionamerica ADS at $21.73,
    representing a premium of approximately 14.4%;
 
                                       44
<PAGE>
        (iv) the Unionamerica Board's review of presentations by, and
    discussions of the terms and conditions of the Offer with, the senior
    executives of Unionamerica, representatives of its legal counsel and
    representatives of DLJ;
 
        (v) the Unionamerica Board's receipt of the opinion of DLJ, dated June
    25, 1997 to the effect that, as of such date and based on, and subject to,
    the assumptions, limitations and qualifications set forth in such opinion,
    the Exchange Ratio to be offered to the Unionamerica Securityholders was
    fair from a financial point of view to such Securityholders (see "Opinion of
    Financial Advisor to Unionamerica"). In connection with its evaluation of
    the Proposed Acquisition, the Unionamerica Board considered the numerous
    transaction and public company financial analyses performed by DLJ and DLJ's
    conclusion that no company or transaction is directly comparable to
    Unionamerica, MMI or the Proposed Acquisition. The Unionamerica Board
    considered DLJ's advice that many qualitative factors are involved in
    valuing a company or analyzing a transaction in the property and casualty
    insurance industry, including assessments of the quality of management, the
    attractiveness of the company's target market, the economics of the products
    being sold and the company's market position relative to its competitors;
 
        (vi) the financial condition of MMI, which would create a market
    capitalization of MMI following the Proposed Acquisition in excess of $500
    million, and MMI's standing in the healthcare risk management industry;
 
       (vii) the potential efficiencies resulting from the elimination of
    expenses relating to Unionamerica's status as a public company, which are
    estimated to be up to approximately $1 million annually, and synergies to be
    realized by combining the operations of MMI and Unionamerica as a result of
    Unionamerica becoming a wholly-owned Subsidiary of MMI;
 
      (viii) the regulatory approvals required to consummate the Proposed
    Acquisition and the favorable prospects for receiving all such approvals;
 
        (ix) the ability of the Unionamerica Securityholders to maintain an
    ownership stake in the combined entity and potentially realize the benefits
    from the Proposed Acquisition;
 
        (x) the potential that medical malpractice insurers for which
    Unionamerica provides reinsurance (representing approximately 23% of total
    revenues for the year ended December 31, 1996) will, as a result of
    Unionamerica's affiliation with MMI's insurance Subsidiaries, view
    Unionamerica as a competitor and seek alternative sources for reinsurance;
 
        (xi) the structure of the Proposed Acquisition, which would permit
    Unionamerica Securityholders to exchange their Unionamerica ADSs for MMI
    Common Stock on a tax-free basis; and
 
       (xii) the terms and conditions of the Acquisition Agreement, including,
    among other things, the fact that Unionamerica's obligations under the
    Acquisition Agreement will be fully discharged in the event a higher
    competing offer is made or a firm intention to make a higher competing offer
    is announced and MMI does not prior to midnight on the tenth business day
    after the day on which the relevant higher competing offer is made or, if
    earlier, publicly announced, announce a revised offer on terms which
    provide, in the reasonable opinion of DLJ, a substantially equivalent or
    greater consideration than the higher competing offer, and a $5 million fee
    is paid to MMI.
 
    The Unionamerica Board considered each of the factors listed above, except
for factor (x), to be beneficial to Unionamerica Securityholders and,
consequently, favorable to its decision to approve the Acquisition Agreement.
Based on this analysis, the Unionamerica Board determined that the Proposed
Acquisition is fair to, and in the best interests of, the Unionamerica
Securityholders. The foregoing discussion of the information and factors
considered by the Unionamerica Board is not intended to be exhaustive, and were
considered collectively by the Unionamerica Board in connection with its review
of the Acquisition Agreement. The decision of the Unionamerica Board to approve
the Acquisition Agreement and the transactions contemplated thereby was based on
its consideration of many factors, including those noted above, taken as a
whole. The Unionamerica Board did not analyze specific factors in isolation. In
view of the variety of factors considered in connection with its evaluation of
the Proposed Acquisition, the Unionamerica Board did not find it practicable to,
and did not, quantify or otherwise assign relative weights to the specific
factors considered in reaching its determination. In addition, individual
members of the Unionamerica Board may have given different weights to different
factors. For a discussion of the interests of Unionamerica's directors and
executive officers in Unionamerica, see "Prospectus Summary-- MMI Common Stock
and Unionamerica ADSs held by Directors, Executive Officers and Their
Affiliates".
 
    THE UNIONAMERICA BOARD UNANIMOUSLY RECOMMENDS THAT UNIONAMERICA
SECURITYHOLDERS TENDER THEIR UNIONAMERICA ADSs IN THE OFFER.
 
                                       45
<PAGE>
OPINION OF FINANCIAL ADVISOR TO UNIONAMERICA
 
    In its role as financial advisor to Unionamerica, DLJ was asked by
Unionamerica to render its opinion to the Unionamerica Board as to the fairness,
from a financial point of view, to the holders of Unionamerica ADSs of the
Exchange Ratio to be offered to the holders of Unionamerica ADSs pursuant to the
terms of the Acquisition Agreement. On June 25, 1997, DLJ delivered its written
opinion (the "DLJ Opinion") to the effect that as of the date of such opinion
and based upon and subject to the assumptions, limitations and qualifications
set forth in such opinion, the Exchange Ratio was fair, from a financial point
of view, to the holders of Unionamerica ADSs.
 
    A COPY OF THE DLJ OPINION IS ATTACHED HERETO AS APPENDIX C. UNIONAMERICA
SECURITYHOLDERS ARE URGED TO READ THE OPINION IN ITS ENTIRETY FOR ASSUMPTIONS
MADE, PROCEDURES FOLLOWED, OTHER MATTERS CONSIDERED AND LIMITS OF THE REVIEW BY
DLJ.
 
    The DLJ Opinion was prepared for the Unionamerica Board and is directed only
to the fairness, from a financial point of view, to the holders of Unionamerica
ADSs, and does not constitute a recommendation to any U.S. Securityholder as to
whether to tender their Unionamerica ADSs.
 
    The DLJ Opinion does not constitute an opinion as to the price at which MMI
Common Stock will actually trade at any time. The Exchange Ratio was determined
in arms' length negotiations between Unionamerica and MMI, in which negotiations
DLJ advised Unionamerica. No restrictions or limitations were imposed by the
Unionamerica Board upon DLJ with respect to the investigations made or the
procedures followed by DLJ in rendering its opinion.
 
    In arriving at its opinion, DLJ reviewed the Acquisition Agreement,
including the exhibits and schedules thereto. DLJ also reviewed financial and
other information that was publicly available or furnished to it by Unionamerica
and MMI, including information provided during discussions with their respective
managements. Included in the information provided during discussions with their
respective managements were certain financial projections of Unionamerica and
MMI for the years ending December 31, 1997 and December 31, 1998 prepared by the
managements of Unionamerica and MMI, respectively. In addition, DLJ compared
certain financial and securities data of Unionamerica and MMI with various other
companies whose securities are traded in public markets, reviewed the historical
stock prices and trading volumes of Unionamerica ADSs and MMI Common Stock,
reviewed prices and premiums paid in other business combinations and conducted
such other financial studies, analyses and investigations as DLJ deemed
appropriate for purposes of rendering its opinion.
 
    In rendering its opinion, DLJ relied upon and assumed the accuracy,
completeness and fairness of all of the financial and other information that was
available to it from public sources, that was provided to it by Unionamerica or
MMI or any of their respective representatives, or that was otherwise reviewed
by it. With respect to the financial projections of Unionamerica supplied to it,
DLJ assumed that they have been reasonably prepared on a basis reflecting the
best currently available estimates and judgments of the management of
Unionamerica as to the future operating and financial performance of
Unionamerica. With respect to the financial projections of MMI supplied to it,
DLJ assumed that they have been reasonably prepared on a basis reflecting the
best currently available estimates and judgments of the management of MMI as to
the future operating and financial performance of MMI. DLJ did not assume any
responsibility for making an independent evaluation of any of the information
reviewed by it. DLJ relied as to all legal matters on advice of counsel to
Unionamerica.
 
    The DLJ Opinion is necessarily based on economic, market, financial and
other conditions as they existed on June 25, 1997, and on the information made
available to it as of, June 25, 1997. It should be understood that, although
subsequent developments may affect its opinion, DLJ does not have any obligation
to update, revise or reaffirm its opinion.
 
                                       46
<PAGE>
    The following is a summary of the presentation made by DLJ to the
Unionamerica Board at its June 13, 1997 meeting, which presentation was
confirmed at the Unionamerica Board meeting held on June 24, 1997.
 
    At the close of business on June 11, 1997, MMI's stock price was $25.25 per
share, resulting in a value per Unionamerica ADS of approximately $21.11, based
on the Exchange Ratio of 0.836 shares of MMI Common Stock for each Unionamerica
ADS.
 
    TRANSACTION ANALYSIS.  DLJ reviewed publicly available information for
selected transactions involving: (i) the acquisition of property and casualty
insurance companies since January 1, 1989 (the "Selected Property and Casualty
Transactions") and, (ii) the acquisition of property and casualty insurance
companies from January 1, 1996 through June 11, 1997 (the "Selected Recent
Property and Casualty Transactions") (together, the "Selected Transactions"). In
reviewing the Selected Transactions, several factors were considered, including:
(i) the lack of publicly available information for subsidiary and private
company transactions which represent a significant portion of the merger and
acquisition activity; and (ii) the lack of directly comparable transactions. The
Selected Transactions were not intended to represent the complete list of
property and casualty insurance company transactions which have occurred. Such
transactions were used in this analysis because the companies involved were
deemed by DLJ to operate in similar businesses or have similar financial
characteristics to Unionamerica and MMI.
 
    DLJ reviewed the consideration paid in the Selected Transactions in terms of
the price paid for the common stock in the Selected Transactions as a multiple
of GAAP operating earnings for the latest twelve months ("LTM") ended prior to
the announcement of such transactions and as a multiple of shareholders' equity
as of the end of the latest fiscal quarter ("LFQ") ended prior to the
announcement of such transactions. In analyzing acquisitions of property and
casualty insurance companies, the purchase price paid may be described in terms
of multiples of the price paid for common stock to GAAP operating earnings and
to shareholders' equity. Variances in multiples for different transactions may
reflect such considerations as the consistency, quality and growth of earnings
and the company's capitalization, asset quality and return on capital. Since
GAAP operating earnings and shareholders' equity already reflect the cost of a
company's debt or preferred stock financing, analyses of multiples of GAAP
operating earnings or shareholders' equity are usually based on the price paid
for the company's common stock, which excludes the cost of assuming, repaying or
redeeming such debt or preferred stock financing. Comparing the multiples of the
price offered to be paid for Unionamerica ADSs by MMI to the GAAP operating
earnings and shareholders' equity of Unionamerica with multiples paid by
acquirors in other transactions indicates whether the valuation being placed on
Unionamerica is within the range of values paid for other property and casualty
insurance companies.
 
    The low, average and high multiples of price paid for common stock to LTM
GAAP operating earnings were 5.0x, 18.5x and 57.3x, respectively, for the
Selected Property and Casualty Transactions. Based on an offer price of $21.11
per share, the implied multiple of price paid for common stock to Unionamerica's
GAAP operating earnings for the LTM ended March 31, 1997 was 9.7x. This multiple
is between the low and average multiples of the Selected Property and Casualty
Transactions. The low, average and high multiples of price paid for common stock
to shareholders' equity as of the end of the LFQ ended prior to the announcement
of the transaction were 0.36x, 1.61x and 3.92x, respectively, for the Selected
Property and Casualty Transactions. Based on an offer price of $21.11 per share,
the implied multiple of price paid for common stock to Unionamerica's
shareholders' equity as of March 31, 1997 was 1.75x. This multiple is higher
than the average multiple of the Selected Property and Casualty Transactions.
 
    The low, average and high multiples of price paid for common stock to LTM
GAAP operating earnings were 7.5x, 16.0x and 29.7x, respectively, for the
Selected Recent Property and Casualty Transactions. Based on an offer price of
$21.11 per share, the implied multiple of price paid for common stock to
Unionamerica's GAAP operating earnings for the LTM ended March 31, 1997 was
9.7x. This multiple is between the low and average multiples of the Selected
Recent Property and Casualty Transactions. The
 
                                       47
<PAGE>
low, average and high multiples of price paid for common stock to shareholders'
equity as of the end of the LFQ ended prior to the announcement of the
transaction were 1.00x, 2.14x and 3.92x, respectively, for the Selected Recent
Property and Casualty Transactions. Based on an offer price of $21.11 per share,
the implied multiple of price paid for common stock to Unionamerica's
shareholders' equity as of March 31, 1997 was 1.75x. This multiple is between
the low and average multiple of the Selected Recent Property and Casualty
Transactions.
 
    DLJ determined the percentage premium of the offer prices (represented by
the purchase price per share in cash transactions and the price of the
constituent securities times the exchange ratio in the case of stock-for-stock
mergers) over the public market trading prices one day, one week and one month
prior to the announcement date of the Selected Transactions involving property
and casualty insurance companies where the acquired company's stock was publicly
traded (the "Selected Public Property and Casualty Transactions"). The average
premiums of offer prices to public market trading prices one day, one week and
one month prior to the announcement date were 35.6%, 40.2% and 52.1%,
respectively, for the Selected Public Property and Casualty Transactions. An
offer price of $21.11 per share represents premiums to the trading prices of
Unionamerica ADSs, one day, one week and one month prior to June 11, 1997, of
11.8%, 26.0% and 26.0%, respectively. These premiums are lower than the
corresponding average premiums of the Selected Public Property and Casualty
Transactions.
 
    DLJ also determined the percentage premium of the offer prices (represented
by the purchase price per share in cash transactions and the price of the
constituent securities times the exchange ratio in the case of stock-for-stock
mergers) over the public market trading prices one day, one week and one month
prior to the announcement date of comparably sized transactions over the latest
twelve months ended June 11, 1997 where the acquired company's stock was
publicly traded (the "Selected Public Transactions"). The average premiums of
offer prices to public market trading prices one day, one week and one month
prior to the announcement date were 15.4%, 20.9% and 26.4%, respectively, for
the Selected Public Transactions. An offer price of $21.11 per share represents
premiums to the trading prices of Unionamerica ADSs, one day, one week and one
month prior to June 11, 1997 of 11.8%, 26.0% and 26.0%, respectively. These
premiums are below, above and below the corresponding average premiums of the
Selected Public Transactions.
 
    PUBLIC COMPANY ANALYSIS.  To provide comparative market information, DLJ
compared selected historical and projected operating and financial ratios of
Unionamerica to the corresponding data and ratios of selected reinsurance
companies whose securities are publicly traded. Such companies included
Chartwell, Everest Re, NAC Re, and Trenwick (the "Selected U.S. Broker Market
Reinsurance Companies") as well as Sphere Drake and Terra Nova (Bermuda)
Holdings (the "Selected London Market Reinsurance Companies") (together, the
"Selected Reinsurance Companies").
 
    Such analysis included, among other things, the ratios of stock price to
GAAP operating earnings per share ("EPS") for the LTM ended March 31, 1997,
estimated GAAP operating EPS for 1997 and 1998 (as estimated by research
analysts and compiled by Institutional Brokers Estimating Service for the
Selected Reinsurance Companies), and shareholders' equity per share as of March
31, 1997. Closing prices as of June 11, 1997 were used in this analysis. The
ratios described in this paragraph have been designed to reflect the value
attributable in the public equity markets to various valuation measures of
reinsurance companies. Measures utilized in the public marketplace to value the
stock of publicly traded companies in the reinsurance industry are based on,
among other things, a company's historical and projected GAAP operating earnings
as well as shareholders' equity. The multiples of stock price to GAAP operating
EPS reflect the value attributed to a company by public equity market investors
based on the company's historical and projected earnings. The multiples of stock
price to shareholders' equity per share reflect the values attributed to a
company by public equity market investors based on the company's net worth.
Variances in multiples for different companies may reflect such considerations
as the consistency, quality and growth of earnings and the company's
capitalization, asset quality and return on capital. Since GAAP operating
earnings and shareholders' equity already reflect the cost of a company's debt
or preferred stock
 
                                       48
<PAGE>
financing, analyses of multiples of GAAP operating earnings or shareholders'
equity are usually based on the price paid for the company's common stock, which
excludes debt or preferred stock financing. Comparing the multiples of price
offered to be paid by MMI to the GAAP operating EPS and shareholders' equity of
Unionamerica with the multiples at which the Selected Reinsurance Companies
trade indicates whether the valuation being placed on Unionamerica is within the
range of values at which the Selected Reinsurance Companies trade.
 
    The low, average and high, multiples of public stock price to GAAP operating
EPS for the LTM ended March 31, 1997 were 10.9x, 13.1x and 14.9x, respectively,
for the Selected U.S. Broker Market Reinsurance Companies. Based on an offer
price of $21.11 per share, the implied multiple of offer price to Unionamerica's
GAAP operating EPS for the LTM ended March 31, 1997 was 9.6x. This multiple is
lower than the low multiple of the Selected U.S. Broker Market Reinsurance
Companies. The low, average and high multiples of public stock price to
estimated 1997 GAAP operating EPS were 9.9x, 11.7x and 12.9x, respectively, for
the Selected U.S. Broker Market Reinsurance Companies. Based on an offer price
of $21.11 per share, the implied multiple of offer price to Unionamerica's
estimated 1997 GAAP operating EPS was 10.1x. This multiple is between the low
and average multiple of the Selected U.S. Broker Market Reinsurance Companies.
The low, average and high multiples of public stock price to estimated 1998 GAAP
operating EPS were 9.1x, 10.5x and 11.4x, respectively, for the Selected U.S.
Broker Market Reinsurance Companies. Based on an offer price of $21.11 per
share, the implied multiple of offer price to Unionamerica's estimated GAAP
operating EPS for 1998 was 9.0x. This multiple is lower than the low multiple of
public stock price to estimated 1998 GAAP operating EPS of the Selected U.S.
Broker Market Reinsurance Companies. The low, average and high multiples of
public stock price to shareholders' equity per share as of March 31, 1997 were
1.14x, 1.41x and 1.68x, respectively, for the Selected U.S. Broker Market
Reinsurance Companies. Based on an offer price of $21.11 per share, the implied
multiple of offer price to Unionamerica's shareholders' equity per share as of
March 31, 1997 was 1.75x. This multiple is higher than the high multiple of the
Selected U.S. Broker Market Reinsurance Companies.
 
    The low, average and high multiples of public stock price to GAAP operating
EPS for the LTM ended March 31, 1997 were 5.8x, 7.9x and 9.9x, respectively, for
the Selected London Market Reinsurance Companies. Based on an offer price of
$21.11 per share, the implied multiple of offer price to Unionamerica's GAAP
operating EPS for the LTM ended March 31, 1997 was 9.6x. This multiple is higher
than the average multiple of the Selected London Market Reinsurance Companies.
The low, average and high multiple of public stock price to estimated 1997 GAAP
operating EPS were 8.9x, 9.0x and 9.1x, respectively, for the Selected London
Market Reinsurance Companies. Based on an offer price of $21.11 per share, the
implied multiple of offer price to Unionamerica's estimated 1997 GAAP operating
EPS was 10.1x. This multiple is higher than the high multiple of the Selected
London Market Reinsurance Companies. The low, average and high multiples of
public stock price to estimated 1998 GAAP operating EPS were 7.7x, 8.0x and
8.3x, respectively, for the Selected London Market Reinsurance Companies. Based
on an offer price of $21.11 per share, the implied multiple of offer price to
Unionamerica's estimated GAAP operating EPS for 1998 was 9.0x. This multiple is
higher than the high multiple of public stock price to estimated 1998 GAAP
operating EPS of the Selected London Market Reinsurance Companies. The low,
average and high multiples of public stock price to shareholders' equity per
share as of March 31, 1997 were 0.67x, 1.08x and 1.49x, respectively, for the
Selected London Market Reinsurance Companies. Based on an offer price of $21.11
per share, the implied multiple of offer price to Unionamerica's shareholders'
equity per share as of March 31, 1997 was 1.75x. This multiple is higher than
the high multiple of the Selected London Market Reinsurance Companies.
 
    Since the consideration received pursuant to the Offer will be in the form
of MMI Common Stock, to provide comparative market information, DLJ compared
selected historical and projected operating and financial ratios of MMI to the
corresponding data and ratios of W.R. Berkley, Frontier, Gainsco, HCC, Markel,
Navigators, NYMagic, Penn-America and RLI Corp. (the "Selected Specialty
Insurance Companies") and FPIC, MAIC Holdings, PICOM, St. Paul Companies and
SCPIE (the "Selected Medical Malpractice Companies") (together, the "Selected
Companies").
 
                                       49
<PAGE>
    Such analysis included, among other things, the ratios of stock price to
GAAP operating EPS for the LTM ended March 31, 1997, estimated GAAP operating
EPS for 1997 and 1998 (as estimated by research analysts and compiled by
Institutional Brokers Estimating Service for the Selected Companies), and to
shareholders' equity per share as of March 31, 1997. Closing prices as of June
11, 1997 were used in this analysis. Comparing the multiples at which the
Selected Companies trade indicates whether MMI's Common Stock price is within
the range of values at which the Selected Companies trade.
 
    The low, average and high multiples of public stock price to GAAP operating
EPS for LTM ended March 31, 1997, were 9.8x, 15.3x and 22.3x, respectively, for
the Selected Specialty Insurance Companies, and 9.0x, 11.8x and 16.1x,
respectively, for the Selected Medical Malpractice Companies. The multiple of
price to MMI's GAAP operating EPS for LTM ended March 31, 1997 was 10.9x. This
multiple is between the low and average multiple of both the Selected Specialty
Insurance Companies and the Selected Medical Malpractice Companies. The low,
average and high multiples of public stock price to estimated 1997 GAAP
operating EPS were 9.6x , 13.6x and 19.1x, respectively, for the Selected
Specialty Insurance Companies, and 9.1x, 11.5x and 13.6x, respectively, for the
Selected Medical Malpractice Companies. The multiple of price to MMI's estimated
1997 GAAP operating EPS was 10.7x. This multiple is between the low and the
average multiple of both the Selected Specialty Insurance Companies and the
Selected Medical Malpractice Companies. The low, average and high multiples of
public stock price to estimated 1998 GAAP operating EPS were 8.1x, 11.6x and
15.6x, respectively, for the Selected Specialty Insurance Companies, and 8.7x,
10.4x and 12.5x, respectively, for the Selected Medical Malpractice Companies.
The multiple of price to MMI's estimated 1998 GAAP operating EPS was 9.4x. This
multiple is between the low and the average multiple of both the Selected
Specialty Insurance Companies and the Selected Medical Malpractice Companies.
The low, average and high multiples of public stock price to shareholders'
equity per share as of March 31, 1997 were 1.12x, 2.11x and 3.84x, respectively,
for the Selected Specialty Insurance Companies, and 0.89x, 1.46x and 1.84x,
respectively, for the Selected Medical Malpractice Companies. The multiple of
price to MMI's shareholders' equity per share as of March 31, 1997 was 1.20x.
This multiple is between the low and the average multiple of both the Selected
Specialty Insurance Companies and the Selected Medical Malpractice Companies.
 
    No company or transaction used in the Transaction Analysis or the Public
Company analysis described above was directly comparable to Unionamerica, MMI or
the Proposed Acquisition. Accordingly, an analysis of the results of the
foregoing was not simply mathematical nor necessarily precise; rather, it
involved complex considerations and judgments concerning differences in
financial and operating characteristics of companies and other factors that
could affect the transaction values and trading prices. For example, many
qualitative factors are involved in valuing a company or analyzing a transaction
in the property and casualty insurance industry, including assessments of the
quality of management, the attractiveness of the company's target market, the
economics of the products being sold and the company's market position relative
to its competitors. Other factors that could affect the transaction values or
trading prices include differences in distribution, products, geographic or
demographic customer concentration, size, accounting practices, asset portfolio
quality, interest rate sensitivity and other factors. These factors may affect
the transaction values of trading prices in each case by affecting in varying
degrees investors' expectations of such factors as the company's risk and future
operating profitability.
 
    STOCK TRADING HISTORY.  To provide contextual data and comparative market
data, DLJ examined the history of the trading prices and their relative
relationships for both Unionamerica ADSs and MMI Common Stock for various
periods ended prior to June 11, 1997. DLJ also reviewed the daily closing prices
of Unionamerica ADSs and MMI Common Stock and compared the Unionamerica and MMI
closing stock prices with the S&P 500 Index and indices of selected publicly
traded companies. In addition, DLJ reviewed the trading history of Unionamerica
ADSs and MMI Common Stock relative to indices of selected publicly traded
companies in order to assess the relative stock price performance of
Unionamerica, MMI and such indices.
 
                                       50
<PAGE>
    PRO FORMA MERGER ANALYSIS.  DLJ analyzed certain pro forma financial effects
resulting from the Proposed Acquisition. In conducting its analysis, DLJ relied
upon certain assumptions described above and financial projections provided by
the managements of Unionamerica and MMI. DLJ analyzed the pro forma effect of
the Proposed Acquisition on the EPS, shareholders' equity per share and leverage
ratios of the combined companies. MMI's management has indicated that it
believes that the Proposed Acquisition will offer some modest consolidation
opportunities which will result in revenue enhancements and expense savings
relative to the stand-alone projected revenues and expenses of Unionamerica and
MMI. DLJ incorporated estimates of such revenue enhancements and expense
savings, determined in conjunction with the managements of Unionamerica and MMI,
in its analysis, although DLJ did not express any opinion as to the likelihood
of such revenue enhancements or expense savings realized. The results of the pro
forma merger analysis are not necessarily indicative of future operating results
or financial position. Based on this analysis and on an offer price of $21.11
per share, holders of MMI's Common Stock would realize EPS accretion of 2.8%,
and 6.5%, respectively, in 1997 and 1998. Based on this analysis and on an offer
price of $21.11 per share, the MMI ratio of debt to total capitalization as of
March 31, 1997 would be 19.9%, assuming the Proposed Acquisition is completed.
There can be no assurance as to whether the assumptions regarding financial
projections set forth in this paragraph will occur, and such assumptions are
used only for purposes of illustration.
 
    CONTRIBUTION ANALYSIS.  DLJ analyzed Unionamerica's and MMI's relative
contributions to the combined company with respect to GAAP operating revenues,
GAAP operating earnings, shareholders' equity and total assets and compared this
with the relative ownership of Unionamerica Securityholders in the combined
company after the Proposed Acquisition. Such analysis was considered on a
percentage contribution basis and was made, where appropriate, (i) for 1996 and
for the LTM ended March 31, 1997 based on MMI's and Unionamerica's historical
financial results and (ii) with respect to estimated GAAP operating earnings for
1997 and 1998, as projected by Unionamerica's and MMI's management.
 
    Unionamerica's relative contribution to the combined company with respect to
revenues and net operating income for 1996 were 37.7% and 43.0%, respectively,
of the total. Unionamerica's relative contribution to the combined company with
respect to estimated GAAP operating earnings for 1997 and 1998 were 38.0% and
37.1%, respectively, of the total. Unionamerica's relative contribution to the
combined company with respect to total assets was 41.5% of the total.
Unionamerica's relative contribution to shareholder's equity as of December 31,
1996 was 30.0% of the total.
 
    Based on the Exchange Ratio of 0.836, Unionamerica Securityholders would own
approximately 38.0% of the combined company after the Proposed Acquisition. The
results of these contribution analyses are not necessarily indicative of the
contributions that the respective business may actually make in the future.
 
    The summary set forth above does not purport to be a complete description of
the analysis performed by DLJ but describes, in summary form, the principal
elements of the presentation made by DLJ to the Unionamerica Board on June 13,
1997 in connection with its preparation of the DLJ Opinion. The preparation of a
fairness opinion involves various determinations as to the most appropriate and
relevant methods of financial analysis and the application of these methods to
the particular circumstances and, therefore, such an opinion is not readily
susceptible to summary description. Each of the analyses conducted by DLJ was
carried out in order to provide a different perspective on the Proposed
Acquisition and add to the total mix of information available. DLJ did not form
a conclusion as to whether any individual analysis, considered in isolation,
supported or failed to support an opinion as to fairness, from a financial point
of view. Rather, in reaching its conclusion, DLJ considered the results of the
analyses in light of each other and ultimately reached its opinion based on the
results of all analyses taken as a whole. DLJ did not place particular reliance
or weight on any individual analysis, but instead concluded that its analyses,
taken as a whole, supported its determination. Accordingly, notwithstanding the
separate factors summarized above, DLJ believes that its analyses must be
considered as a whole and the selected portions of its analyses and the factors
considered by it, without considering all analyses and factors, may create an
incomplete view of the evaluation process underlying the DLJ Opinion. In
performing its analyses, DLJ
 
                                       51
<PAGE>
made numerous assumptions with respect to industry performance, business and
economic conditions and other matters. The analyses performed by DLJ are not
necessarily indicative of actual values or future results, which may be
significantly more or less favorable than suggested by such analyses.
 
    The Unionamerica Board selected DLJ as its financial advisor because it is a
nationally recognized investment banking firm that has substantial experience in
transactions similar to the Proposed Acquisition and is familiar with
Unionamerica, its business and the property and casualty insurance industry.
Pursuant to the terms of an engagement letter dated June 13, 1997 between
Unionamerica and DLJ, Unionamerica paid DLJ $250,000 upon rendering of the DLJ
Opinion. Pursuant to the terms of the engagement letter, Unionamerica will pay
DLJ, on the Closing Date, cash compensation equal to seven-eighths of one
percent (0.875%) of the Transaction Value, less the $250,000 paid to date.
Transaction Value is defined as the aggregate amount of consideration received
by Unionamerica and/or the Unionamerica Securityholders (treating any shares
issuable upon exercise of options, warrants or other rights of conversion that
are outstanding as of June 25, 1997, as outstanding, and subtracting from this
amount the exercise price of these options, warrants or other rights of
conversion), plus the amount of any debt assumed, acquired, remaining
outstanding, retired or defeased or preferred stock redeemed or remaining
outstanding in connection with the Proposed Acquisition, including, in the case
of a sale or other disposition by Unionamerica of assets, the net value of any
assets not sold by Unionamerica. Based on an assumed Transaction Value,
Unionamerica will pay DLJ, on the Closing Date, cash compensation of
approximately $1.9 million, less the $250,000 paid to date. Unionamerica also
agreed to reimburse DLJ for all out-of-pocket expenses (including the reasonable
fees and out-of pocket expenses of counsel) incurred by DLJ in connection with
its engagement and to indemnify DLJ and certain related persons against certain
liabilities in connection with its engagement, including liabilities under the
federal securities laws. The terms of the fee arrangement with DLJ, which DLJ
and Unionamerica believe are customary in transactions of this nature, were
negotiated at arms' length between Unionamerica and DLJ and the Unionamerica
Board are aware of such arrangement, including the fact that a significant
portion of the aggregate fee payable to DLJ is contingent upon consummation of
the Proposed Acquisition.
 
    In the ordinary course of business, DLJ may actively trade the securities of
both Unionamerica and MMI for its own account and for the accounts of its
customers and accordingly, may at any time hold a long or short position in such
securities. DLJ, as part of its investment banking services, is regularly
engaged in the valuation of businesses and securities in connection with
mergers, acquisitions, underwritings, sales and distributions of listed and
unlisted securities, private placements and valuations for estate, corporate and
other purposes. DLJ has performed investment banking and other services for
Unionamerica in the past, including lead-managing Unionamerica's initial public
offering in December, 1995, and has received usual and customary compensation
for such services. DLJ has performed investment banking and other services in
transactions involving MMI in the past including representing HPIC in its sale
to MMI, and has received usual and customary compensation for such services.
 
PROPOSED REFINANCING OF BANK DEBT
 
    MMI presently is considering, subject to market conditions, to refinance the
combined bank debt of MMI and Unionamerica after closing the Proposed
Acquisition (approximately $103 million) through a private placement to
institutional investors of approximately $100 million of preferred trust
securities during November or December 1997. The offering will be made through
the issuance of the Refinancing Securities. MMI will agree to file a
registration statement for an exchange offer for the Refinancing Securities,
which will not be registered under the Securities Act and may not be offered and
sold in the U.S. absent registration or an applicable exemption from
registration requirements. There is no assurance that MMI will decide to proceed
with such refinancing. See "--Description of MMI Capital Stock" and "Appendix D"
for a description of restrictions on dividends and distributions on, and
purchases of, MMI Common Stock in the event MMI elects to defer payment of
interest on the subordinated debentures. MMI has no present intention to elect
to defer interest payments on the subordinated debentures.
 
                                       52
<PAGE>
DESCRIPTION OF MMI CAPITAL STOCK
 
    The authorized capital stock of MMI as of the completion of the Offer will
consist of 30,000,000 shares of Common Stock, $0.10 par value per share, and
5,000,000 shares of Preferred Stock, $20.00 par value per share, the rights,
preferences and powers of which may be designated by the MMI Board.
 
    COMMON STOCK.  Each share of MMI Common Stock entitles its holder to one
vote on each matter brought before a meeting of the stockholders.
 
    The MMI Certificate does not grant MMI's stockholders preemptive rights to
subscribe for any additional issues of MMI Common Stock. The shares of MMI
Common Stock have no redemption or conversion rights. All outstanding shares of
MMI Common Stock are legally issued, fully paid and non-assessable.
 
    Subject to the limitations on dividends and other restrictions described in
Appendix D--"Certain Market, Dividend and Exchange Rate Information", registered
holders of shares of MMI Common Stock are entitled to receive such dividends as
may be declared from time to time by the MMI Board out of the funds legally
available therefor.
 
    PREFERRED STOCK.  The MMI Board is authorized by the MMI Certificate,
without first obtaining the approval of the holders of MMI Common Stock, to
issue from time to time shares of Preferred Stock which may have such voting
powers, full or limited, or no voting powers, and such designations, preferences
and relative, participating, optional or other special rights, qualifications,
limitations or restrictions thereof, as shall be stated in the resolution or
resolutions providing for the issuance of such stock adopted by the MMI Board.
The MMI Board without obtaining stockholder approval could issue shares of
Preferred Stock with voting and conversion rights that could adversely affect
the voting power of the holders of shares of MMI Common Stock and discourage a
hostile takeover of MMI.
 
    SHAREHOLDER RIGHTS PLAN.  On June 14, 1997, the MMI Board adopted a
shareholder rights plan pursuant to the Rights Agreement between MMI and
ChaseMellon Shareholder Services L.L.C., as Rights Agent, and declared a
dividend distribution of one Right for each outstanding share of MMI Common
Stock, payable to MMI's stockholders of record at the close of business on June
30, 1997. One Right attaches to each share of MMI Common Stock and each Right
will entitle the registered holder to purchase from MMI a Unit of Series B
Preferred Stock, at a purchase price of $75.00 per Unit (the "Purchase Price"),
subject to adjustment. All shares of MMI Common Stock issued in the Offer to the
holders of Unionamerica ADSs will entitle such holders to the Rights set forth
in the Rights Agreement.
 
    The Rights will separate from the MMI Common Stock upon the earlier of (i)
ten days following a public announcement that a Person or group of affiliated or
associated Persons (an "Acquiring Person") has acquired, or obtained the right
to acquire beneficial ownership of 15% or more of the outstanding shares of MMI
Common Stock (the "Stock Acquisition Date"), or (ii) ten business days (or such
later date as the MMI Board may determine) following the commencement of a
tender offer or exchange offer that would result in a Person or group becoming
an Acquiring Person (a Person or group of affiliated or associated Persons who
has acquired beneficial ownership of 15% or more of the outstanding MMI Common
Stock). The earlier of (i) and (ii) is known as the "Distribution Date". The
Rights are not exercisable until the Distribution Date and will expire at the
close of business on June 30, 2007, unless earlier redeemed or extended by MMI.
The MMI Board has excluded from the number of shares used to determine whether
or not a Person becomes an Acquiring Person the shares of MMI Common Stock
received directly from MMI by any Person by exchange in the Offer for
Unionamerica ADSs which such Person beneficially owned as of June 25, 1997
solely on account of such receipt; provided, however, that neither (i) any such
Person who acquires any additional beneficial ownership of MMI Common Stock, nor
(ii) any transferee from such Person, is excluded.
 
                                       53
<PAGE>
    In the event that any Person becomes an Acquiring Person, each holder of a
Right will thereafter have the right to receive upon exercise MMI Common Stock
(or, in certain circumstances, cash, property or other securities of MMI) having
a value equal to two times the Purchase Price. Notwithstanding any of the
foregoing, following the occurrence of such a flip-in event, all Rights that are
beneficially owned by any Acquiring Person will be null and void.
 
    In the event that following the Stock Acquisition Date, (i) MMI engages in a
merger or business combination transaction in which MMI is not the surviving
corporation; (ii) MMI engages in a merger or business combination transaction in
which MMI is the surviving corporation and the MMI Common Stock is changed or
exchanged; or (iii) 50% or more of the MMI assets or earning power is sold or
transferred, each holder of a Right (except Rights which have previously been
voided as set forth above) shall thereafter have the right to receive, upon
exercise of the Right, common stock of the acquiring company having a value
equal to two times the Purchase Price.
 
    Generally, at any time until ten days following the Stock Acquisition Date,
MMI may redeem the Rights in whole, but not in part, at a price of $0.01 per
Right. Until a Right is exercised, the holder thereof will have no rights as a
stockholder of MMI, including, without limitation, the right to vote or receive
dividends.
 
    DELAWARE LAW AND CERTAIN CORPORATE PROVISIONS.  Pursuant to the MMI
Certificate, the MMI Board is divided into three classes serving staggered
three-year terms. Directors can be removed from office only with cause and only
by the affirmative vote of the holders of a majority of the then outstanding
shares of capital stock entitled to vote in an election of directors. Vacancies
on the MMI Board may be filled only by the remaining directors, and not by the
stockholders.
 
    The MMI Certificate also provides that any action required or permitted to
be taken by the stockholders of MMI may be effected only at an annual or special
meeting of stockholders and prohibits stockholder action by written consent in
lieu of a meeting. The MMI Certificate and the MMI Bylaws provide that special
meetings of stockholders may be called only by the MMI Board. Stockholders are
not permitted to call a special meeting or to require that the MMI Board call a
special meeting of stockholders except as applicable law may require.
 
    The MMI Certificate authorizes, and the MMI Bylaws establish, an advance
notice procedure, other than by or at the direction of the MMI Board, for the
nomination of candidates for election as directors, as well as for other
stockholder proposals to be considered at annual meetings of stockholders. In
general, notice of intent to nominate a director or to raise business at such
meeting must be received by MMI not less than 30 days prior to the date of the
meeting; and must contain certain specified information concerning the person to
be nominated or the matter to be brought before the meeting and concerning the
stockholder submitting the proposal.
 
    MMI is subject to Section 203 of the DGCL ("Section 203"). Section 203
restricts certain transactions and business combinations between a corporation
and an "Interested Stockholder" owning 15% or more of the corporation's
outstanding voting stock, for a period of three years from the date the
stockholder becomes an Interested Stockholder. Subject to certain exceptions,
unless the transaction is approved by the MMI Board and the holders of at least
66.67% of the outstanding voting stock of the corporation (excluding shares held
by the Interested Stockholder), Section 203 prohibits significant business
transactions such as a merger with, disposition of assets to, or receipt of
disproportionate financial benefits by, the Interested Stockholder, or any other
transaction that would increase the Interested Stockholder's proportionate
ownership of any class or series of the corporation's stock. The statutory ban
does not apply if, upon consummation of the transaction in which any Person
becomes an Interested Stockholder, the Interested Stockholder owns at least 85%
of the outstanding voting stock of the corporation (excluding shares held by
Persons who are both directors and officers or by certain employee stock plans).
 
                                       54
<PAGE>
    The foregoing provisions regarding the "Shareholder Rights Plan" and
"Delaware Law and Certain Corporate Provisions" could have the effect of
discouraging attempts to acquire MMI or remove incumbent directors even if some
or a majority of MMI's stockholders deem such an attempt to be in MMI's and
their best interest and even if the potential acquiror is willing to pay a
premium over the prevailing market price of MMI Common Stock.
 
    LIMITATIONS ON DIRECTORS' LIABILITY.  The MMI Certificate provides that no
director of MMI shall be liable to MMI or its stockholders for monetary damages
for breach of fiduciary duty as a director, except for liability (i) for any
breach of the director's duty of loyalty to MMI or its stockholders; (ii) for
acts or omissions not in good faith or which involve intentional misconduct or a
knowing violation of law; (iii) in respect of certain unlawful dividend payments
or stock redemptions or repurchases; or (iv) for any transaction from which the
director derived an improper personal benefit. The effect of these provisions is
to eliminate the rights of MMI and its stockholders (through stockholders'
derivative suits on behalf of MMI) to recover monetary damages against a
director for breach of certain fiduciary duties as a director (including
breaches resulting from grossly negligent behavior), except in the situations
described above. These provisions will not limit the liability of directors
under federal securities laws.
 
    TRANSFER AGENT AND REGISTRAR.  The transfer agent and registrar for the MMI
Common Stock is ChaseMellon Shareholder Services L.L.C., New York, New York.
 
DESCRIPTION OF UNIONAMERICA CAPITAL STOCK
 
    The amount of the authorized capital stock of Unionamerica consists of
20,000,000 shares of Unionamerica Common Stock and 50,000 shares of Deferred
Stock. The Unionamerica Common Stock is represented by the Unionamerica ADSs
evidenced by ADRs issued by Morgan Guaranty Trust Company of New York, as
depositary (the "Depositary"), pursuant to a Deposit Agreement (the "Deposit
Agreement") dated as of December 1, 1995 among Unionamerica, the Depositary and
the owners from time to time of ADRs issued thereunder.
 
    COMMON STOCK.  As of October 31, 1997, Unionamerica had 8,510,157 shares of
Unionamerica Common Stock issued and outstanding, each such share of
Unionamerica Common Stock being represented by a Unionamerica ADS. The holders
of Unionamerica Common Stock are entitled to receive such dividends as may be
recommended by the Unionamerica Board and approved by Unionamerica in a general
meeting. No larger dividend may be declared than is recommended by the
Unionamerica Board, but the Unionamerica Securityholders may by ordinary
resolution declare a smaller dividend. In addition, the Unionamerica Board may
declare interim dividends from time to time. Under English law, dividends may
only be paid from the distributable profits of a company determined on an
unconsolidated basis under U.K. GAAP and calculated on a cumulative basis,
netting undistributed realized profits from all periods against realized losses
(including provisions) from all periods.
 
    Subject to the restrictions referred to below, at a meeting of shareholders
every holder of Unionamerica Common Stock present in person or, in the case of a
corporation, by a duly authorized representative or proxy shall have one vote on
a show of hands, and on a poll, every holder of Unionamerica Common Stock
present in person or by a duly authorized representative or proxy shall have one
vote for every share held. Notwithstanding the foregoing, the Unionamerica
Articles contain certain provisions that limit the voting rights that may be
exercised by certain Unionamerica Securityholders. The first set of such
provisions, the IRC Voting Provisions, are intended to prevent Unionamerica
Securityholders (and holders of Unionamerica ADSs) from certain adverse
consequences under the "controlled foreign corporation" rules under the IRC,
although no assurance can be given that such provisions will in fact effectively
prevent such consequences. Under the IRC Voting Provisions, if, and so long as,
any U.S. Shareholder (as defined below) directly, indirectly or constructively
owns, within the meaning of Section 958 of the IRC, shares of Unionamerica
Common Stock having ten percent or more or the total number of votes exercisable
in respect of the Unionamerica Common Stock, the voting rights attributable to
such shares will be limited, in
 
                                       55
<PAGE>
the aggregate, to such whole number of votes which is nearest to, but less than,
ten percent of the total number of votes. The IRC Voting Provisions further
provide that (i) Acadia Partners, L.P. will not be permitted to vote any shares
of Unionamerica Common Stock and (ii) the Estate of Bernice P. Bishop and UA
Partners, L.P. will not be permitted to exercise any votes in excess of
percentages of the total number of votes determined in accordance with separate
formulas set forth in the Unionamerica Articles, which formulas will in no event
permit the Estate of Bernice P. Bishop or UA Partners, L.P. to vote more than
the whole number of votes which is nearest to, but less than, ten percent of the
total number of votes and may, depending on the circumstances, limit further
their voting rights. "U.S. Shareholder" means any U.S. Person that directly or
indirectly owns, within the meaning of Section 958(a) of the IRC, any shares of
Unionamerica Common Stock, and "U.S. Person" has the same meaning as set out in
Section 7701(a)(30) of the IRC and includes (i) a citizen or resident of the
U.S., (ii) a domestic partnership, (iii) a domestic corporation, and (iv) any
estate or trust (other than a foreign estate or foreign trust).
 
    Under the second set of limitations in the Unionamerica Articles (the
"Section 212 Provisions"), a holder of Unionamerica Common Stock shall not be
entitled to vote shares at any general meeting of shareholders:
 
        (a) if (i) the shares of Unionamerica Common Stock in question represent
    at least three percent of the issued shares and the holder or any other
    Person appearing to be interested in that holder's shares has been given a
    notice under Section 212 of the Companies Act (as described below) and has
    failed to give Unionamerica any information required by the notice within 14
    days of the date of service; or (ii) in any other case, the holder or any
    other Person appearing to be interested in the holder's shares has failed to
    supply the required information within 28 days from the date of any such
    notice; or
 
        (b) unless all amounts presently payable by him in respect of such
    shares have been paid.
 
    The Unionamerica Articles provide that the IRC Voting Provisions and the
Section 212 Provisions are to be applied simultaneously in determining the
number of votes exercisable by any holder and the total number of votes
exercisable in respect of the shares, such that after application of such
provisions, no holder will have a larger portion of the total number of votes
than is permitted by such provisions. Since these provisions have the effect of
reducing the total number of votes that may be exercised with respect to any
matter, the application of such provisions will result in a proportional
increase in the relative voting power of each Unionamerica Securityholder whose
voting power is not reduced by the provisions. Such provisions apply to holders
of Unionamerica ADSs as well as to holders of Unionamerica Common Stock, and do
not apply to the Depositary or to International Insurance Advisors, Inc., as
agent for certain Unionamerica Securityholders. Such provisions could make it
difficult or impossible for any Person or group of Persons acting in concert to
acquire control of Unionamerica without agreement by the Unionamerica Board and
Unionamerica Securityholders. At a meeting of the Unionamerica Securityholders
held on October 30, 1997, the Unionamerica Securityholders considered and
approved a resolution to amend the Unionamerica Articles to disapply the IRC
Voting Provisions in the event that any person (whether or not a U.S. Person)
acquires or contracts to acquire by virtue of acceptances of a takeover offer
not less than eight-tenths in nominal value of the issued and outstanding shares
of Unionamerica Common Stock.
 
    AMERICAN DEPOSITARY RECEIPTS.  ADRs evidencing Unionamerica ADSs are
issuable by the Depositary pursuant to the Deposit Agreement. Each Unionamerica
ADS represents one share of Unionamerica Common Stock or the right to receive
such share of Unionamerica Common Stock deposited with the London office of the
Depositary. An ADR may represent any number of Unionamerica ADSs. Only persons
in whose names ADRs are registered will be treated by Unionamerica and the
Depositary as owners and holders of ADRs.
 
    Unionamerica will pay certain charges of the Depositary under the Deposit
Agreement, but such charges do not include stock transfer or other taxes and
other governmental charges (which are payable by ADR holders) or cable, telex,
facsimile transmission and delivery charges incurred at the request of ADR
 
                                       56
<PAGE>
holders delivering ADRs (which are payable by such holders). Any tax or other
governmental charge payable by or on behalf of any custodian or the Depositary
with respect to any ADR shall be payable by the holder of such ADR to the
Depositary. The Depositary may refuse to effect registration of transfer of such
ADR until such payment is made, and may withhold or deduct from any
distributions on deposited shares of Unionamerica Common Stock or may sell for
the account of the holder thereof any part or all of the deposited shares of
Unionamerica Common Stock underlying such ADR, and may apply such withholding or
deduction or the proceeds of any such sale in payment of any such tax or other
governmental charge, the holder of such ADR remaining liable for any deficiency.
 
    As a condition precedent to the registration of transfer of any ADR, the
Depositary or any custodian may require: (a) the payment of a sum sufficient to
pay or reimburse it for payment of (i) any stock transfer or other tax or other
governmental charge with respect thereto; (ii) any stock transfer or
registration fees for the registration of transfers of shares of Unionamerica
Common Stock upon any applicable register; and (iii) any charges of the
Depositary upon delivery of ADRs against deposits of shares of Unionamerica
Common Stock; (b) the production of proof satisfactory to it as to the identity
and genuineness of any signature, and as to citizenship, residence, exchange
control provision, legal or beneficial ownership or other information as it may
deem necessary or proper or as Unionamerica may require by written request to
the Depositary; and (c) compliance with such reasonable regulations, if any, as
the Depositary and Unionamerica may establish consistent with the provisions of
the Deposit Agreement. The transfer of ADRs, in particular circumstances or
generally, may be suspended when the transfer books of the Depositary or
Unionamerica are closed or whenever any such action is deemed necessary or
advisable by the Depositary or Unionamerica.
 
    DEFERRED STOCK.  As of October 31, 1997, Unionamerica had 50,000 shares of
Deferred Stock allotted and issued, credited as fully paid. The holders of the
Deferred Stock have no rights to receive notice of, or to attend, speak or vote
at any general meeting of Unionamerica, nor are they entitled to receive any
dividend or other distribution. Upon the winding up of Unionamerica, the holders
of Deferred Stock shall only be entitled to the amounts paid upon the Deferred
Stock after repayment of the capital paid up on the Unionamerica Common Stock
plus the payment of $10 million per each share of such Unionamerica Common
Stock. Unionamerica has the authority to appoint any Person to execute on behalf
of the holders of Deferred Stock a transfer or agreement to transfer the
Deferred Stock without the consent of the holders of the Deferred Stock and
without any payment to the holders for the Deferred Stock.
 
    The Deferred Stock has no conversion rights, redemption rights or preemption
rights and otherwise does not provide any material rights to holders other than
as described above. The Deferred Stock was issued to assure Unionamerica's
compliance with certain technical provisions of the Companies Act which require
that at least L50,000 of the capital of Unionamerica be denominated in U.K.
currency. The remainder of Unionamerica's share capital is denominated in U.S.
dollars.
 
CHANGES IN THE RIGHTS OF UNIONAMERICA SECURITYHOLDERS
 
    The following discussion is a comparison of certain rights of Unionamerica
Securityholders and MMI stockholders. Such comparison does not purport to be a
complete description of the differences between the statutory and other rights
of Unionamerica Securityholders and MMI stockholders. Such differences can be
determined in full by reference to the laws and applicable regulatory
requirements in England and the U.S., the Companies Act, the DGCL and the common
law thereunder, the Unionamerica Articles and Memorandum of Association and the
MMI Certificate and MMI Bylaws.
 
    IN GENERAL.  Unionamerica is incorporated under English law. Those
Unionamerica Securityholders who exchange their holdings of Unionamerica ADSs
for MMI Common Stock and whose rights as shareholders are currently governed by
English law, including the Companies Act, and the Unionamerica Articles, will,
upon the exchange of Unionamerica ADSs, become MMI stockholders and their rights
as stockholders will be governed by the laws of the U.S. and by the DGCL and the
common law thereunder,
 
                                       57
<PAGE>
the MMI Certificate and MMI Bylaws. Both Unionamerica and MMI are subject to the
regulations of the NYSE.
 
    Certain differences between the rights of Unionamerica Securityholders and
MMI stockholders are set out below. These differences arise from differences
between English law and the laws of the U.S. and the DGCL as well as from
differences between the corporate governing instruments of the two companies.
 
VOTING RIGHTS AND QUORUM REQUIREMENTS
 
    UNIONAMERICA.  Under English law, the voting rights of shareholders are
regulated by a company's articles of association. A separate resolution must be
proposed for the appointment of each director (other than the directors
appointed by the Unionamerica Board) and, accordingly, Unionamerica
Securityholders are not entitled to cumulative voting rights in the election of
directors. Cumulative rights, if they existed, would entitle a Unionamerica
Securityholder to cast as many votes for directors as he has shares of stock
multiplied by the number of directors to be elected. Each shareholder may then
allocate such shareholder's votes for one or more of the candidates. The
Unionamerica Articles specify that two Unionamerica Securityholders (regardless
of the number of shares held by them) present in person or by proxy and entitled
to vote upon the business to be transacted at the meeting shall be a quorum. Any
Unionamerica Securityholder on the register may vote in person or, assuming the
proxy is received by Unionamerica at least 48 hours prior to the time set for
the meeting, by proxy. There is no record date for meetings under English law.
 
    Subject to disenfranchisement in the event of non-compliance with a
statutory notice requiring disclosure as to beneficial ownership, each
registered Unionamerica Securityholder present in person (or, if a corporation,
present by a duly authorized representative or proxy) is entitled to one vote at
any Unionamerica meeting for each resolution (ordinary or special) considered on
a show of hands. Voting occurs by show of hands unless a poll is demanded. If a
poll is taken, every Unionamerica Securityholder, or his proxy, is entitled to
cast one vote for each unit of Unionamerica Common Stock held or represented by
a Unionamerica ADS. At shareholder meetings a poll may be demanded by: (i) the
chairman of the meeting; (ii) at least two shareholders present in person or by
proxy and entitled to vote at the meeting; (iii) a shareholder or shareholders
present in person or by proxy representing not less than one-tenth of the total
voting rights of all shareholders having the right to vote at the meeting; or
(iv) a shareholder or shareholders present in person or by proxy holding shares
of Unionamerica Securities conferring the right to vote at the meeting on which
an aggregate sum has been paid up equal to not less than one-tenth of the total
sum paid up on all shares conferring that right. If a poll is demanded, one may
be taken at the meeting (and must be on a poll demanded on the election of a
chairman or on a question of adjournment) or not more than 30 days following the
meeting as the chairman shall direct. The Unionamerica Articles provide that in
certain circumstances, rights, including voting rights, of shares in
Unionamerica may be suspended. See "Description of Unionamerica Capital Stock".
Furthermore, the Unionamerica Articles state that the voting rights of certain
named Unionamerica Securityholders are restricted.
 
    MMI.  Under the DGCL, each holder of MMI Common Stock at the record date set
for a meeting of stockholders is entitled to one vote per share owned, subject
to certain limitations discussed below. See "Required Vote for Authorization of
Certain Corporate Actions and Certain Provisions Relating to Business
Combinations".
 
    Under the DGCL, a corporation with stock outstanding or subscribed
ordinarily may amend its charter provided that the amendment is recommended by
the board of directors and approved by the affirmative vote of a majority of all
the votes entitled to be cast. Holders of a class of stock may vote as a class
if the amendment would increase or decrease the number of authorized shares of
such class or the par value of shares of such class, or would alter the
preferences, powers, or special rights of any class so as to affect them
adversely.
 
    The MMI Certificate does not provide for any supermajority requirements or
any special voting rights for MMI Common Stock. However, the MMI Board is
authorized by the MMI Certificate, without first
 
                                       58
<PAGE>
obtaining the approval of the holders of MMI Common Stock, to issue from time to
time shares of Preferred Stock which may have such voting powers, full or
limited, or no voting powers, and such designations, preferences and relative,
participating, optional or other special rights, qualifications, limitations or
restrictions thereof, as shall be stated in the resolution or resolutions
providing for the issue of such stock adopted by the MMI Board. The MMI
Directors, without obtaining stockholder approval, could issue shares of
Preferred Stock with voting and conversion rights that could adversely affect
the voting power of the holders of shares of MMI Common Stock.
 
    Unionamerica Securityholders who are currently entitled to vote as a class
on certain changes under English law or the Unionamerica Articles will no longer
be entitled to do so after the consummation of the Offer (including in the case
of merger and other business combinations, as discussed below). For a discussion
of the MMI Certificate, see "Description of MMI Capital Stock--Delaware Law and
Certain Corporate Provisions".
 
MEETINGS OF UNIONAMERICA SECURITYHOLDERS
 
    UNIONAMERICA.  Under English law, the annual general meeting ("AGM") of a
public limited company must be held each year and at least once every fifteen
months. An extraordinary general meeting ("EGM") of a company may be convened by
the board of directors or, notwithstanding any provision to the contrary in a
company's articles of association, by a request from shareholders holding not
less than one-tenth of the paid-up capital of the company carrying voting rights
at general meetings. An EGM at which an ordinary resolution is proposed requires
14 days' notice (other than an ordinary resolution to remove a director which
requires 28 days' notice). An ordinary resolution requires a majority of those
present (in person or by proxy) and voting to vote in favor. An EGM at which a
special resolution is proposed requires 21 days' notice and such resolution
requires a three quarter majority of those present (in person or by proxy) and
voting to vote in favor. An AGM requires 21 days' notice regardless of the types
of resolution to be proposed. Such notice periods exclude the day when the
notice is given or deemed to be given and the day for which it is given.
 
    MMI.  Under the DGCL, MMI is required to hold an annual meeting of
stockholders. The MMI Bylaws provide that the annual meeting shall be held
within 180 days after December 31 of each year at such time and place as may be
determined by the MMI Board. The MMI Certificate and MMI Bylaws provide that
special meetings of stockholders may be called only by the MMI Board.
Stockholders are not permitted to call a special meeting or to require that the
MMI Board call a special meeting of stockholders except as applicable law may
require. Under the MMI Bylaws, MMI stockholders must receive written notice of
any special meeting not less that ten, or in the case of a merger or
consolidation, not less than 20, but not more than 60 days prior to such
meeting. MMI stockholders are entitled to written notice of any annual meeting
not less than 10 days prior to such annual meeting. The record date for the
meetings of the stockholders shall not be less than 10 days (or 20 days if a
merger or consolidation is to be acted upon at such meeting) nor more than 60
days before the date of such meetings.
 
CERTAIN ACTIONS AT SHAREHOLDER MEETINGS
 
    UNIONAMERICA.  Under English law and the Unionamerica Articles, certain
business may be conducted at an AGM or an EGM only if the requisite notice of
such business has been given prior to such meeting. As discussed above, to be
properly brought before a general meeting, notice of such business must be given
to shareholders a certain number of days prior to the meeting. Under the
Companies Act, shareholders holding not less than one-twentieth of the total
voting rights of all shareholders having the right to vote at the relevant
meeting (or not less than 100 shareholders holding shares on which there has
been paid up an average per shareholder of not less than L100) may require
Unionamerica to circulate notice of any resolution which those shareholders may
properly propose and wish to propose at that meeting. In addition, pursuant to
the Unionamerica Articles, the Unionamerica Securityholders can, by ordinary
resolution in general meeting, appoint any person who is willing to act to be a
director.
 
                                       59
<PAGE>
Furthermore, certain "Designated Shareholders" (as defined in the Unionamerica
Articles) can appoint up to two directors to the Unionamerica Board provided
they maintain a certain percentage shareholding.
 
    MMI.  Pursuant to the MMI Certificate, any action required or permitted to
be taken by the MMI stockholders must be effected at an annual or duly called
special meeting of the stockholders, and may not be effected by any consent in
writing by such stockholders. Except as otherwise required by the DGCL, special
meetings of stockholders may be called at any time and only pursuant to a
resolution of a majority of the MMI Board. At any special meeting of the MMI
stockholders, only such business may be conducted as shall have been brought
before the meeting by or at the direction of the MMI Board.
 
    Pursuant to the MMI Bylaws, at any annual meeting of the MMI stockholders,
only such business shall be conducted as shall have been brought before the
meeting (i) by or at the direction of the MMI Board or (ii) by any MMI
stockholder who is entitled to vote with respect thereto and who complies with
the following notice requirements. For business to be properly brought before an
annual meeting by a MMI stockholder, the stockholder's notice must be delivered
or mailed to and received at the principal executive offices of MMI not less
than 30 days prior to the date of the annual meeting; provided, however, that in
the event that less than 40 days' notice or prior public disclosure of the date
of the meeting is given or made to MMI stockholders, to be timely, an MMI
stockholder's notice must be so received not later than the close of business on
the tenth day following the day on which such notice of the date of the annual
meeting was mailed or such public disclosure was made. An MMI stockholders'
notice to the secretary of MMI shall set forth as to each matter such
stockholder proposes to bring before the annual meeting (a) a brief description
of the business desired to be brought before the annual meeting and the reasons
for conducting such business at the annual meeting; (b) the name and address, as
they appear on MMI's books, of the stockholder proposing such business; (c) the
class and number of shares of MMI capital stock that are beneficially owned by
such stockholder, and (d) any material interest of such stockholder in such
business. Notwithstanding anything in the MMI Bylaws to the contrary, no
business shall be brought before or conducted at any annual meeting except in
accordance with the provisions set forth above. The officer of MMI or other
person presiding at the annual meeting shall, if the facts so warrant, determine
and declare to the meeting that business was not properly brought before the
meeting in accordance with such provisions and, if he or she should determine,
he or she shall so declare to the meeting and any such business so determined to
be not properly brought before the meeting shall not be transacted.
 
REQUIRED VOTE FOR AUTHORIZATION OF CERTAIN CORPORATE ACTIONS AND CERTAIN
  PROVISIONS RELATING TO BUSINESS COMBINATIONS
 
    UNIONAMERICA.  Under the Companies Act, the Unionamerica Articles generally
may be amended and other fundamental corporate changes, such as the passing of a
resolution for winding up, non pro rata issuances of shares for cash, reductions
of capital (subject to sanction by the court), and certain repurchases of
shares, may be authorized by a special resolution passed at a general meeting of
shareholders. Subject to the provisions of the Companies Act, if, at such time,
the capital of Unionamerica is divided into different classes of shares and the
amendment or other resolution would cause any of the special rights attached to
any class of shares to be varied or abrogated, the amendment must also be
sanctioned in writing by the holders of at least two-thirds in nominal value of
the issue shares of the class concerned or by resolution approved by the holders
of not less than two-thirds in nominal value of the issued shares of the class
concerned or by resolution at a separate general meeting of the holders of the
shares of that class.
 
    Mergers or consolidations of English companies are normally conducted
pursuant to takeover offers, schemes of arrangement or, in certain
circumstances, a scheme of reconstruction under Section 110 of the Insolvency
Act 1986. The Companies Act provides that where a takeover offer is made for the
shares of a company and, within four months of the date of the offer, the
offeror has by virtue of acceptances of the offer, acquired or contracted to
acquire at least 90% in value of the shares to which the offer relates, the
offeror may, within two months of reaching the 90% level, by notice, acquire the
shares held by shareholders who have not accepted the offer on the same terms as
the offer. Such a shareholder may
 
                                       60
<PAGE>
apply to the court within six weeks of the date on which notice was given
objecting to the transfer or its proposed terms. The court may order that the
shareholder shall not be required to transfer his shares, or may specify such
terms for the transfer as it finds appropriate. In addition, where the offeror
holds or has contracted to acquire at least 90% in value of the shares of the
company and does not give such a notice to shareholders who have not accepted
the offer, such a shareholder is entitled to require the offeror to purchase his
shares on the same terms as the offer, even if the offer is otherwise closed for
acceptance.
 
    Schemes of arrangement are arrangements or compromises between a company and
any class or classes of its shareholders (or any class or classes of its
creditors) and are used for certain types of reconstructions, amalgamations,
capital reorganizations or takeovers. Schemes of arrangement require the
approval at an extraordinary general meeting of the company of a majority in
number, representing 75% in value, of holders of the relevant class of shares
(or creditors) present and voting, either in person or by proxy, and the
sanction of the High Court of Justice in England and Wales. Once so approved and
sanctioned, all shareholders (or, as the case may be, creditors) of the relevant
class are bound by the terms of the scheme. A scheme of reconstruction under
Section 110 of the Insolvency Act 1986 may be made when a company is being wound
up voluntarily. Under the terms of such a scheme with the sanction of a special
resolution of shareholders in a general meeting, the whole or part of the
company's business or property is transferred to a second company in
consideration for the issue or transfer to them of shares in the second company.
Any dissenting shareholder can require the liquidator to abstain from carrying
the resolution into effect or to purchase his interest at a price agreed or
determined by arbitration.
 
    In the U.K., takeovers of public limited companies, such as Unionamerica,
are regulated by the City Code. The City Code is administered by the Panel, a
body comprising representatives of certain City of London financial and
professional institutions which oversees the conduct of such takeovers. The City
Code includes certain restrictions on action being taken by a target company to
frustrate a takeover offer, including the issue of new shares without the prior
approval of its shareholders.
 
    MMI.  For a discussion of the required vote for authorization of certain
corporate actions and certain provisions relating to business combinations, see
"Description of MMI Capital Stock."
 
    MMI is subject to the requirements of the Exchange Act, including those
provisions which regulate tender offers. The Exchange Act imposes requirements
on the form of an offer to purchase a registered corporation's shares and also
requires bidders to make comprehensive and detailed disclosures when their
offers commence. The requirements relating to a tender offer prescribe a 20
business day minimum offering period, shareholder withdrawal rights coextensive
with the offering period, withdrawal rights after 60 days from the date of the
initial offer if the offeror has failed to pay, PRO RATA acceptance for
oversubscribed offers, nondiscrimination among offerees, and the extension of
any price increase during the tender offer to all shareholders who have already
tendered. Also, during the tender offer, purchases otherwise than pursuant to a
tender offer and any short tenders by offerees are prohibited. The Exchange Act,
unlike the City Code, does not contain provisions which (i) require an offer to
be for a minimum amount of stock, (ii) require mandatory cash offers, or (iii)
restrict the implementation of certain defensive actions by the directors of a
target company without first obtaining shareholder approval; however, the DGCL
and applicable common law may impose certain restrictions on such actions.
 
    The foregoing provisions regarding the Shareholder Rights Plan, Section 203
of the DGCL, and the Exchange Act could have the effect of discouraging attempts
to acquire MMI or remove incumbent directors even if some or a majority of MMI's
stockholders deem such an attempt to be in MMI's and their best interest and
even if the potential acquiror is willing to pay a premium over the prevailing
market price of MMI Common Stock.
 
DISSENTERS' RIGHTS
 
    UNIONAMERICA.  Under English law, shareholders do not generally have
dissenters' rights, as the concept is understood under the DGCL, and the
Unionamerica Articles do not contain any dissenters' rights. Certain limited
rights analogous to dissenters' rights exist where an offeror who, pursuant to a
 
                                       61
<PAGE>
takeover offer for a company, has acquired or contracted to acquire not less
than nine-tenths in value of the shares to which the offer relates, seeks to
acquire outstanding minority shareholdings pursuant to the compulsory
acquisition provisions under the Companies Act. Similarly, under a scheme of
reconstruction under Section 110 of the U.K. Insolvency Act 1986, a dissenting
shareholder can require the liquidator to abstain from carrying the resolution
into effect or to purchase his interest at a price agreed or determined by
arbitration. See "Required Vote for Authorization of Certain Actions and Certain
Provisions Relating to Business Combinations". In addition, under English law,
any shareholder who complains that the affairs of the company are being
conducted or that the powers of the directors of the company are being exercised
in a manner unfairly prejudicial to him or some part of the shareholders
(including himself), or in disregard of his proper interests as a shareholder,
may apply to the High Court of Justice in England for relief. If the High Court
finds the complaint to be justified, it may in the exercise of its discretion
order the purchase of the shares of any shareholders by other shareholders or by
the company itself, on such terms including as to price as the High Court may
determine. See "Required Vote for Authorization of Certain Actions and Certain
Provisions Relating to Business Combinations".
 
    MMI.  Under the DGCL, a stockholder of a corporation participating in
certain major corporate transactions may, under varying circumstances, be
entitled to receive cash equal to the fair market value of the shares held by
such stockholder (as determined by a court of competent jurisdiction or by
agreement of the stockholder and the corporation), in lieu of the consideration
such stockholder would otherwise receive in the transaction. The DGCL does not
require dissenters' rights with respect to (a) a sale of assets, (b) a merger by
a corporation, if the shares of the corporation are either listed on a national
securities exchange or designated as a national market security on an
interdealer quotation system by the National Association of Securities Dealers,
Inc. or held by more than 2,000 shareholders of record or if stockholders
receive shares of the surviving corporation or of a listed or widely-held
corporation, or (c) a merger in which the corporation is the surviving
corporation if no vote of its stockholders is required to approve the merger.
 
DIVIDENDS
 
    UNIONAMERICA.  English law permits payment of dividends by a company only
out of distributable profits (which are its accumulated, realized profits (not
previously utilized by distribution or capitalization) less accumulated,
realized losses) and not out of share capital or share premium. The payment of
dividends on ordinary shares is subject to the prior right to dividends of any
preference shares. The excess of the consideration for the issue of shares over
the par value of such shares must (except in certain limited circumstances) be
credited to a share premium account and may not be paid out as dividends but
may, however, be used to pay up unissued shares which may then be distributed to
shareholders in proportion to their holdings and for other limited purposes. In
addition, Unionamerica, as a public limited company, may make a distribution at
any time only if, at that time and immediately after such distribution, the
amount of its net assets is not less than the aggregate of its called-up (i.e.
issued and paid up) share capital and undistributable reserves. Under English
law, a dividend must be declared by reference to relevant accounts showing the
availability of distributable reserves for such dividend. As a public limited
company, the relevant accounts for Unionamerica are its last audited accounts
or, where such accounts do not show sufficient distributable reserves, interim
accounts (which need not be audited) prepared and filed with the Registrar of
Companies of England and Wales.
 
    Under the Unionamerica Articles, the directors may pay to Unionamerica
Securityholders such interim dividends (i.e. dividends resolved to be paid by
directors without the approval of shareholders in a general meeting), as appear
to the directors to be justified by the distributable profits of Unionamerica.
Any dividend unclaimed after the period of 12 years from the date of its
declaration may, at the discretion of the directors, be forfeited and shall
revert to Unionamerica. Each dividend on Unionamerica ADSs will be paid to those
holders of Unionamerica ADSs on the register of members on the record date for
such dividend who have not waived their entitlement thereto. Such record date
will normally be about six weeks before the date of payment.
 
                                       62
<PAGE>
    MMI.  The DGCL permits the payment of dividends out of surplus or, if there
is no surplus, out of net profits for the fiscal year in which dividends are
declared and the preceding fiscal year (provided that the amount of capital of
the corporation is not less than the aggregate amount of the capital represented
by the issued and outstanding stock of all classes having a preference upon the
distribution of assets). In addition, the DGCL generally provides that a
corporation may redeem or repurchase its own shares only if such redemption or
repurchase would not "impair the capital" of the corporation. The ability of a
Delaware corporation to pay dividends on, or redeem or to make repurchases or
redemptions of, its shares is dependent on the financial status of the
corporation standing alone and not on a consolidated basis. In determining the
amount of surplus of a Delaware corporation, the assets of the corporation,
including stock of subsidiaries owned by the corporation, must be valued at
their fair market value as determined by the board of directors, without regard
to their historical value.
 
    The MMI Certificate does not contain restrictions or preferences on the
declaration or payment of dividends. The policy of the MMI Board is to pay
regular quarterly cash dividends. The declaration and payment of dividends is
subject to the discretion of the MMI Board and will depend upon general business
conditions, legal and contractual restrictions on the payment of dividends and
other factors that the MMI Board deems relevant.
 
    As an insurance holding company, MMI depends in large part on dividends and
other payments from its Subsidiaries for the payment of cash dividends to MMI
stockholders. In the case of MMI's insurance Subsidiaries, such payments are
restricted by insurance laws, and insurance regulators have authority in certain
circumstances to prohibit payments of dividends and other amounts by MMI's
insurance Subsidiaries that would otherwise be permitted without regulatory
approval. MMI's bank credit agreement also restricts the payment of dividends.
 
    As described under "Prospectus Summary--Proposed Refinancing of Bank Debt,"
MMI presently intends, subject to market conditions, to issue in November 1997,
in a private placement to institutional investors, approximately $100 million of
preferred trust securities. The offering will be made through the issuance of
the Refinancing Securities. So long as no event of default under the
subordinated debentures has occurred and is continuing, MMI will have the right
to defer payment of interest on the subordinated debentures at any time or from
time to time for a period not exceeding 10 consecutive semi-annual periods for
each extension period. At the end of any such extension period, MMI must pay all
accrued and unpaid interest together with additional interest thereon. During
any such extension period, among other things, MMI may not declare or pay any
dividends or distributions on, or redeem, purchase, acquire, or make a
liquidation payment with respect to, any of its capital stock, except for
dividends or distributions in shares of, or options, warrants or rights to
subscribe for or purchase shares of, MMI Common Stock. MMI has no present
intention to elect to defer payment of interest on the subordinated debentures.
 
    Unionamerica Securityholders who receive MMI Common Stock in the Offer in
exchange for their Unionamerica ADSs will be entitled to any dividend declared
on shares of MMI Common Stock with a record date after the Expiration Date,
including any extension thereof.
 
    The NYSE generally requires a listed company to notify the NYSE of the
record date for the payment of any dividend no later than ten days prior to such
record date.
 
PRE-EMPTIVE RIGHTS
 
    UNIONAMERICA.  Under English law when a company issues equity shares (or
grants certain other rights to acquire equity shares) ("equity securities") in
consideration for payment of cash, then unless certain provisions of the
Companies Act are disapplied by a special resolution of shareholders, existing
shareholders are entitled to participate in the offer for such equity securities
pro rata to their existing
 
                                       63
<PAGE>
shareholdings. The usual practice of a listed company is, pursuant to the
Companies Act, to seek general disapplication by special resolution of statutory
pre-emption rights on an annual basis (i) in respect of its entire unissued
ordinary share capital, where the equity securities are to be issued by way of
rights to existing shareholders and (ii) to disapply the statutory pre-emption
rights on the issue for cash of equity securities representing not more than
five percent of the company's then issued ordinary share capital. The
Unionamerica Articles disapply the statutory pre-emption provisions to the
fullest extent permitted under the Companies Act, so that pursuant to the
Unionamerica Articles all unissued shares of Unionamerica Common Stock are at
the disposal of the Unionamerica Board, which may offer, allot, grant options
for or otherwise dispose of them to such Persons, at such time, for such
consideration and upon such terms and conditions as the Unionamerica Board may
determine. However, under English law, shares may not be issued at a discount
(i.e., may not be issued in consideration for a payment of an amount less than
the nominal or par value of the shares so issued).
 
    MMI.  Under the DGCL, stockholders do not have preemptive rights unless a
corporation affirmatively elects preemptive rights in its certificate of
incorporation. The MMI Certificate does not provide holders of shares of MMI
Common Stock with preemptive rights.
 
    The NYSE requires shareholder approval when shares of common stock or
securities convertible into or exercisable for common stock are to be issued in
any transaction or series of related transactions, other than a public offering
for cash, (i) if the common stock to be issued will have voting power equal to
or greater than 20% or more of the voting power outstanding before such
issuance, or (ii) the number of shares of common stock to be issued will be in
excess of 20% of the number of shares of common stock outstanding before the
issuance of the stock.
 
LIMITATION OF LIABILITY AND INDEMNIFICATION OF OFFICERS AND DIRECTORS
 
    UNIONAMERICA.  English law does not permit a company to indemnify a
director, secretary or other officer of the company against any liability which
by virtue of any rule of law would otherwise attach to him in respect of
negligence, default, breach of duty or breach of trust in relation to the
company except liability incurred by such director or officer in defending any
legal proceeding (whether civil or criminal) in which judgment is given in his
favor or in which he is acquitted or in certain instances where, although he is
liable, a court finds such director or officer acted honestly and reasonably and
that having regard to all the circumstances he ought fairly to be excused and
relief is granted by the court. However, a company is permitted to purchase
insurance for directors and officers against such liability which by virtue of
law or otherwise would attach to such directors and officers in respect of any
negligence, default, breach of duty or breach of trust of which they or any of
them may be guilty in relation to Unionamerica. Unionamerica has purchased and
maintains in force such insurance.
 
    MMI.  The DGCL provides that the indemnification provided for in the DGCL
shall not be deemed exclusive of any other rights under any bylaw, agreement,
vote of stockholders or disinterested directors, or otherwise, and provides that
expenses may be advanced to officers and directors in a specific case upon
receipt of an undertaking to repay such amount if it is ultimately determined
that the indemnified party is not entitled to be indemnified. In addition, the
DGCL permits the determination as to whether an officer or director has met the
applicable standard of conduct to be made in certain circumstances by
independent legal counsel.
 
    The DGCL provides that the board of directors has the ultimate
responsibility for managing the business and affairs of a corporation. In
discharging this function, the law holds directors to fiduciary duties of care
and loyalty to the corporation and its stockholders. The Delaware Supreme Court
has held that the duty of care requires the exercise of an informed business
judgment. An informed business judgment means that directors have informed
themselves of all material information reasonably available to them. Having
become so informed, they then must act with requisite care in the discharge of
their duties. Liability of directors of a Delaware corporation to the
corporation or its stockholders for breach of
 
                                       64
<PAGE>
the duty of care in some circumstances requires a finding by a court that the
directors were grossly negligent. For additional information, see "Description
of MMI Capital Stock--Limitations on Directors' Liability."
 
    Directors also have a duty of loyalty to the corporation and its
stockholders. The duty of loyalty requires that, in making a business decision,
directors act in good faith and in the honest belief that the action taken was
in the best interests of the corporation.
 
    The MMI Bylaws provide for indemnification for any person who is or was a
party, or is threatened to be made a party, to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of MMI) by reason of the
fact that such person is or was a director, officer, employee or agent of MMI,
or who is or was serving at the request of MMI as a director, officer, employee
or agent of another corporation, partnership, joint venture, trust or other
enterprise, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by such person in
connection with such action, suit or proceeding, if such person acted in good
faith and in a manner he believed to be in, or not opposed to, the best
interests of MMI, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.
 
    In addition, the MMI Bylaws provide for indemnification for any person who
is or was a party, or is threatened to be made a party, to any threatened,
pending or completed action, suit by or in the right of MMI to procure a
judgment in its favor by reason of the fact that such person is or was a
director, officer, employee or agent of MMI, or who is or was serving at the
request of MMI as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, against expenses
(including attorneys' fees) actually and reasonably incurred by him in
connection with the defense or settlement of such action or suit, if such person
acted in good faith and in a manner he believed to be in, or not opposed to, the
best interests of MMI, except that no indemnification is made in respect of any
claim, issue or matter as to which such person shall have been adjudged to be
liable for negligence or a misconduct in the performance of his duty to MMI,
unless, and only to the extent that, the court in which action or suit was
brought shall determine upon application that, despite the adjudication of
liability, but in view of all the circumstances of the case, such person is
fairly and reasonably entitled to indemnity for such expenses as the court shall
deem proper.
 
    To the extent a director, officer, employee or agent, or former director,
officer, employee or agent of MMI has been successful, on the merits or
otherwise, in the defense of any action, suit or proceeding referred to in the
MMI Bylaws, or in the defense of any claim, issue or matter therein, he will be
indemnified by MMI against expenses (including attorneys' fees) actually and
reasonably incurred by him in connection therewith.
 
    The indemnification provided by the MMI Bylaws is not deemed exclusive of
any other rights to which those seeking indemnification may be entitled under
the MMI Certificate, the MMI Bylaws, any agreement, vote of MMI stockholders or
disinterested directors, or otherwise, both as to actions in his official
capacity and as to actions in another capacity while holding such office.
 
UNIONAMERICA SECURITYHOLDERS' SUITS
 
    UNIONAMERICA.  In addition to having the right to institute proceedings on
behalf of a company, in certain limited circumstances, English law allows an
individual shareholder to bring an action in his own name as the representative
of shareholders where his (and their) rights as shareholders are threatened. In
addition a shareholder can petition the court for relief where the company's
affairs are being or have been conducted in a manner unfairly prejudicial to the
interests of the shareholders generally or of some group of the shareholders, of
which the petitioning shareholder must be a member, or where any actual or
proposed act or omission of the company is or would be so prejudicial. A court
when granting relief in an action complaining of unfair prejudice has wide
discretion, including authorizing civil proceedings to be
 
                                       65
<PAGE>
brought in the name of the company by a shareholder against the Persons
responsible for the prejudicial actions. Except in these limited respects,
English law does not permit class action lawsuits by shareholders on behalf of a
company or on behalf of other shareholders.
 
    MMI.  Under Delaware law, a stockholder may only bring a derivative action
on behalf of the corporation if the stockholder was a stockholder of the
corporation at the time of the transaction in question or his or her stock
thereafter was received by him or her by operation of law. An individual
stockholder also may commence a class action suit on behalf of himself or other
similar situated stockholders where the requirements for maintaining a class
action under Delaware and U.S. federal law have been met.
 
BOARD OF DIRECTORS
  CLASSIFICATION AND APPOINTMENT OF DIRECTORS
 
    UNIONAMERICA.  The Unionamerica Articles provide that unless otherwise
determined by special resolution, there shall be not less than two directors but
there shall be no maximum number. They further provide that at each AGM
one-third (or the number nearest to one-third) of the directors who are subject
to retirement by rotation shall retire from office. The directors appointed by
the Designated Shareholders are not subject to retirement by rotation. The
directors to retire by rotation in every year are those who have been longest in
office since their last election, but, as between persons who became directors
on the same day, those to retire (unless they otherwise agree among themselves)
are to be determined by lot. A retiring director is eligible for re-election.
All directors not initially appointed at an AGM hold office only until the end
of the next AGM and are then eligible for re-election (but are not taken into
account in determining the directors who are to retire at such meeting). See
"Certain Actions at Shareholder Meetings" above. Any director may be removed
from office at any time by an ordinary resolution passed by the Unionamerica
Securityholders of which special notice has been given in accordance with the
Companies Act, except that this is without prejudice to the rights of the
Designated Shareholders to appoint a director. See "Certain Actions at
Shareholder Meetings".
 
    MMI.  Pursuant to the MMI Certificate, the MMI Board is divided into three
classes serving staggered three-year terms. Directors can be removed from office
only with cause and only by the affirmative vote of the holders of a majority of
the then outstanding shares of capital stock entitled to vote in an election of
directors. Vacancies on the MMI Board may be filled only by the remaining
directors, and not by the stockholders.
 
    The MMI Bylaws provide that the number, terms of office and qualification of
the directors of MMI is as specified in Article Sixth of the MMI Certificate.
Article Sixth of the MMI Certificate provides that the number of directors which
constitutes the MMI Board shall be as provided from time to time by resolution
of the MMI Board, which number is currently set at 12. In connection with the
Offer, MMI shall increase the size of its Board by two members to 14 members.
Under the DGCL, the certificate of incorporation or a bylaw adopted by the vote
of the stockholders may provide for the division of directors into two or three
classes and specify the term of office of each class. The MMI Certificate
currently provides for a board of directors of three classes of nearly equal
size, each with three year terms. Accordingly, at each annual meeting of MMI
stockholders, approximately one-third of the MMI Board will stand for election.
The MMI Certificate provides that each director elected shall hold office for
the number of years elected, and upon the anniversary date of his or her
election, his or her term shall expire unless terminated earlier by his death,
resignation or removal. Vacancies and newly-created directorships resulting from
any increase in the authorized number of directors may be filled by the vote of
a majority of the directors then in office, although less than a quorum, and any
director so chosen shall hold office until the next annual election of directors
and until his successor is duly elected and qualified or until his earlier
death, resignation or removal. Directors of MMI need not be stockholders of MMI.
 
                                       66
<PAGE>
CONFLICTS OF INTEREST
 
    UNIONAMERICA.  The Unionamerica Articles provide that a director who is a
party to, or otherwise interested in, any transaction or arrangement with
Unionamerica shall declare the nature and extent of his material interest to the
Unionamerica Board, and having so disclosed his interest may be a party to that
transaction or arrangement. The director may act for himself in a professional
capacity for Unionamerica, other than as auditor, and is entitled to
remuneration for those services. The director is not accountable to Unionamerica
for any benefit he derives through that transaction or arrangement.
 
    MMI.  The MMI Bylaws provide that no director, officer or employee of MMI
shall have any position with, or a substantial interest in, any other business
enterprise whether operated for a profit or not, the existence of which would
conflict or might reasonably be supposed to conflict with the proper performance
of his or her duties or responsibilities to MMI, or which might tend to affect
his or her independence of judgment with respect to transactions between MMI and
such other business enterprise, without full and complete disclosure thereof to
the MMI Board. Each director, officer or employee who has such a conflicting
interest with respect to any transaction which he or she knows is under
consideration by the MMI Board or any of its committees is required to make
timely disclosure thereof so that it may be part of the directors' consideration
of the transaction. The MMI Board, who may act through an appropriate committee,
shall adopt such regulations and procedures as shall from time to time appear to
them sufficient to secure compliance with this policy.
 
BORROWING POWERS
 
    UNIONAMERICA.  Subject to the provisions of the Companies Act, the
Unionamerica Articles provide that its directors may exercise all the powers of
Unionamerica to borrow money and to mortgage and charge its property,
undertaking and assets, including its uncalled or unpaid capital, and to issue
debentures and other securities and to give guarantees.
 
    MMI.  The MMI Bylaws provide that no loans shall be contracted on behalf of
MMI and no evidence of indebtedness shall be issued in its name unless
authorized by a resolution of the MMI Board, except that indebtedness in the
ordinary course of MMI's business not in excess of $1,000,000 or of one year
duration in a single or series of related transactions, may be incurred upon
written approval of the President and Treasurer. The authority granted may be
general or confined to specific instances.
 
COMPENSATION
 
    UNIONAMERICA.  The Unionamerica Articles provide that the fees of the
directors for holding office as such shall not exceed L30,000 per annum in
aggregate or such greater sum as shall from time to time be determined by the
shareholders by ordinary resolution. The directors may also grant additional
remuneration to a director who performs special services to Unionamerica at its
request, and may determine the remuneration of any director holding executive
office. Directors are also entitled to be repaid all traveling, hotel and other
expenses properly incurred by them in connection with their attendance at
meetings and discharge of their duties.
 
    MMI.  The MMI Bylaws provide that the directors may be paid their expenses,
if any, of attendance at each meeting of the MMI Board and any committee thereof
of which they are members. Furthermore, the MMI Bylaws provide that the MMI
Board, irrespective of any personal interest of any of its members, has
authority to fix compensation of all directors for service to MMI as directors,
officers, or otherwise.
 
SHAREHOLDERS' RIGHTS OF INSPECTION
 
    UNIONAMERICA.  Except when such registers are closed in accordance with the
provisions of the Companies Act, the register and index of names of shareholders
of an English company, together with certain other registers required to be
maintained by such a company, may be inspected by its shareholders
 
                                       67
<PAGE>
during business hours without charge (and by other Persons upon payment of a
charge) and copies of such registers may be obtained on payment of an
appropriate charge. A shareholder in an English company may, without charge,
also inspect the minutes of meetings of the shareholders during business hours
and obtain copies upon payment of a charge. The published directors' report and
audited annual accounts of an English company are required to be laid before the
shareholders in a general meeting and a shareholder is entitled to a copy of
such reports and accounts. Further copies are filed with the Registrar of
Companies in England and Wales from whom copies are publicly available upon
payment of the appropriate fee. The shareholders have no further statutory
rights to inspect the accounting records of a company or the minutes of meetings
of directors.
 
    MMI.  The DGCL gives any stockholder of record the right to inspect the
stockholders' list for a purpose reasonably related to such Person's interest as
a stockholder and, during the ten days preceding a stockholders' meeting, for
any purpose germane to that meeting. In addition, the MMI Bylaws provide that
any MMI stockholder shall, upon written demand under oath stating the purpose
thereof, have the right during usual business hours to inspect for any proper
purpose MMI's stock ledger, a list of the MMI stockholders, and its other books
and records, and to make copies or extracts therefrom.
 
DISCLOSURE OF INTERESTS
 
    UNIONAMERICA.  Section 198 of the Companies Act provides that a Person
(including a company and other legal entities) who acquired an interest of three
percent or more of any class of shares comprised in a public limited company's
"relevant share capital" (which, for these purposes, means that company's issued
share capital carrying rights to vote in all circumstances at general meetings
of the company) is obliged to notify that company of his interest within two
business days following the day on which the obligation to notify arises. After
the three percent level is exceeded, similar notifications must be made in
respect of whole percentage figure increases or decreases, rounding down to the
next whole number.
 
    For the purposes of the notification obligation, the interest of a Person in
shares means any kind of interest in any shares including interests in any
shares (i) in which his spouse, or his child or stepchild under the age of 18 is
interested, (ii) if a body corporate is interested in them and either (a) that
body corporate or its directors are accustomed to act in accordance with that
Person's directions or instructions or (b) that Person controls one-third or
more of the voting power of that body corporate, or (iii) if another party is
interested in shares and the Person and that other party are parties to a
"concert party" agreement under Section 204 of the Companies Act (being an
agreement which provides for one or more parties to it to acquire interests in
shares of a particular company, which imposes obligations or restrictions on any
one or more of the parties as to the use, retention or disposal of such
interests acquired pursuant to such agreement and any interest in the company's
shares is in fact acquired by any of the parties pursuant to the agreement).
Such a concert party agreement need not be in writing.
 
    In addition, Section 212 of the Companies Act provides that a public company
may by notice in writing require a Person whom the company knows or has
reasonable cause to believe to be, or to have been at any time during the three
years immediately preceding the date on which the notice is issued, interested
in shares comprised in the company's "relevant share capital" to confirm that
fact or (as the case may be) to indicate whether or not that is the case, and
where he holds or has during the relevant time held an interest in such shares,
to give such further information as may be required relating to his interest and
any other interest in the shares of which he is aware. The disclosure must be
made within such reasonable period as may be specified in the relevant notice
(which may, depending on the circumstances, be as short as one or two days). The
Unionamerica Articles provide that where the information has not been provided
within the specified time period, in respect of those shares (the "default
shares"), the board can in its absolute discretion direct that the member shall
not be entitled to vote at a general meeting either personally or by proxy or
exercise any other membership right in respect of the default shares. In
addition, the board can make further directions, including retention of any
dividend payments and prevention of transfer, where the default shares represent
at least three percent of their class of shares. Furthermore,
 
                                       68
<PAGE>
where notice is served by a company under these provisions on a Person who is or
was interested in shares of the company and that Person fails to give the
company any information required by the notice within the time specified in the
notice, the company may apply to the High Court for an order directing that the
shares in question be subject to restrictions prohibiting, among other things,
any transfer of those shares, and the exercise of voting rights in respect of
such shares. In addition, a Person who fails to fulfill the obligations
described above is subject to criminal penalties.
 
    MMI.  As discussed above, MMI is subject to the Exchange Act, which requires
any Person who acquires directly or indirectly the beneficial ownership of five
percent or more of a public company's outstanding equity security to file with
the Commission, within ten days of acquiring such interest, a notice stating the
acquiror's identity and background, source and amount of funds used in making
the purchase, the purpose of the acquisition, the nature of his interest in the
securities, and any contract, arrangements, understandings or relationships with
respect to the securities of the issuer.
 
ACCOUNTING TREATMENT
 
    At the closing of the Proposed Acquisition, each of MMI and Unionamerica
will receive letters, dated as of such closing, from Ernst & Young LLP and KPMG
Audit Plc regarding those firms' concurrence with MMI managements' and
Unionamerica managements' conclusions, respectively, as to the appropriateness
of pooling-of-interests accounting for the Proposed Acquisition under Accounting
Principles Board Opinion No. 16, if the Proposed Acquisition is closed and
consummated in accordance with the terms and conditions of the Acquisition
Agreement. Accordingly, the assets and liabilities of Unionamerica will be
combined with MMI's at their historical recorded bases. Results of operations of
MMI will include the results of Unionamerica for the entire fiscal year in which
the Acquisition occurs. The reported balance sheet amounts and results of
operations of the separate corporations for prior periods will be combined,
reclassified and conformed as appropriate, to reflect the combined balance
sheets and statements of results of operations for MMI.
 
    MMI believes the Proposed Acquisition would not qualify as a
pooling-of-interests under GAAP if, among other things, MMI Common Stock is
exchanged for less than 90% of the outstanding Unionamerica ADSs. A condition to
the closing of the Proposed Acquisition is the requirement that shares
representing 90% of the voting shares of Unionamerica be validly tendered. MMI
does not intend to waive this condition if the 90% tender requirement is not
achieved.
 
    Certain other transactions could have the effect of violating other
requirements for the use of pooling-of-interests accounting, including sales of
MMI Common Stock or Unionamerica ADSs by directors, executive officers or
affiliates of either MMI or Unionamerica. MMI is not aware of any such
transactions. In connection with the Acquisition Agreement, certain directors
and executive officers of Unionamerica have executed Affiliate Letters, pursuant
to which they agreed not to sell any shares of MMI Common Stock or Unionamerica
Securities during the time period that would cause the violation of the
requirements for pooling-of-interests accounting. See "The Offer--Terms of the
Offer and the Proposed Acquisition".
 
TAX CONSEQUENCES OF THE OFFER
 
    GENERAL.  The following discussion of taxation is included for general
information and only relates to the position of a Person (other than a dealer)
who is the absolute beneficial owner of Unionamerica ADSs. The summaries of U.S.
and U.K. tax laws set out below are based on laws and, in the case of the U.K.,
Inland Revenue practice, including the treaty for the prevention of double
taxation between the U.S. and the U.K. (the "Treaty") and, in the case of both
the U.S. and the U.K., judicial and administrative precedent as of the date of
this Prospectus. The summaries are subject to any changes in laws, Inland
Revenue practice (in the case of the U.K.) and precedent occurring after that
date and do not discuss any tax laws other than those of the U.S. and the U.K.
Unionamerica Securityholders (including those resident,
 
                                       69
<PAGE>
ordinarily resident or domiciled in jurisdictions other than the U.S. or the
U.K.) are urged to consult their own tax or other professional advisors as to
the specific tax consequences to them of the Offer.
 
    U.K. TAXATION.  The following paragraphs summarize certain U.K. tax
consequences associated with the exchange of securities pursuant to the Offer
and are intended as a general guide only to the position of Unionamerica
Securityholders who are resident or ordinarily resident in the U.K. for tax
purposes (a "U.K. Resident") or who are U.S. Residents holding Unionamerica ADSs
as investments. This summary, which is based upon an opinion provided by Lovell
White Durrant, U.K. counsel to Unionamerica, is a general guide as to current
legislation and Inland Revenue practice, and does not purport to be
comprehensive nor to describe all potentially relevant tax consequences.
Unionamerica Securityholders should therefore consult their own tax advisors
regarding the tax consequences and any tax reporting requirements applicable to
their own tax situation.
 
    Taxation of U.K. Residents
 
           Taxation of Capital Gains. The exchange of Unionamerica ADSs by a
       U.K. Resident in return for MMI Common Stock will not be treated as a
       disposal or partial disposal of Unionamerica ADSs for the purposes of
       U.K. taxation of chargeable gains provided that the Unionamerica
       Securityholder, either alone or together with Persons connected with him,
       owns not more than five percent of the issued share capital of
       Unionamerica. The MMI Common Stock will instead be treated as the same
       asset as the Unionamerica ADSs acquired at the same time as, and for the
       same price as, the Unionamerica ADSs were acquired. A Unionamerica
       Securityholder who, either alone or together with Persons connected with
       him, holds more than five percent of the issued share capital of
       Unionamerica is advised that clearance has been obtained from the U.K.
       Inland Revenue under Section 138 of the Taxation of Chargeable Gains Act
       1992 of the U.K. in relation to the Offer to the effect that the Board of
       Inland Revenue is satisfied that the exchange of securities pursuant to
       the Offer will be implemented for bona fide commercial reasons and not
       for tax avoidance purposes and provided such clearance is obtained, the
       exchange of Unionamerica ADSs for MMI Common Stock will similarly not be
       treated as a disposal or partial disposal of Unionamerica ADSs for the
       purposes of the taxation of chargeable gains. To the extent a U.K.
       Resident receives cash, in lieu of a fractional share of MMI Common
       Stock, as consideration, it will be treated as making a disposal which
       may, depending upon its individual circumstances, give rise to a
       liability to U.K. taxation of chargeable gains. A subsequent disposal of
       MMI Common Stock by a U.K. Resident may, depending upon individual
       circumstances, give rise to a liability to U.K. taxation of chargeable
       gains.
 
           Stamp Duty and Stamp Duty Reserve Tax. No U.K. stamp duty or stamp
       duty reserve tax will be payable by a U.K. Resident on the transfer of
       its Unionamerica ADSs to MMI. Any liability to U.K. stamp duty or stamp
       duty reserve tax on the transfer of such Unionamerica ADSs to MMI will be
       borne by MMI. No U.K. stamp duty or stamp duty reserve tax will be
       payable on the issue of MMI Common Stock to a U.K. Resident.
 
           Dividends. Dividends, if any, paid on MMI Common Stock to a U.K.
       Resident will normally be subject to U.K. tax, subject to any applicable
       credit for U.S. tax borne in respect of the dividend.
 
    Taxation of U.S. Residents
 
           This summary, which is based upon an opinion by Lovell White Durrant,
       U.K. counsel to Unionamerica, is a general guide as to current U.K.
       legislation and practice, and does not purport to be comprehensive nor to
       describe all potentially relevant tax considerations. U.S. Residents
       should therefore consult their own tax advisors regarding the tax
       consequences and any tax reporting requirements applicable to their own
       tax situation.
 
                                       70
<PAGE>
           U.K. Taxation of Capital Gains. The exchange of Unionamerica ADSs by
       a U.S. Resident in return for MMI Common Stock will not normally be
       subject to U.K. taxation of chargeable gains unless at the time of the
       disposal such U.S. Resident carries on a trade, profession or vocation in
       the U.K. through a branch or agency and the Unionamerica ADSs are or have
       been used, held or acquired for the purposes of such trade (or profession
       or vocation), branch or agency, in which event such U.S. Resident should
       refer to the relevant comments contained above in "Taxation of U.K.
       Residents"--"Taxation of Capital Gains".
 
           Stamp Duty and Stamp Duty Reserve Tax. No U.K. stamp duty or stamp
       duty reserve tax will be payable by a U.S. Resident on the transfer of
       its Unionamerica ADSs to MMI. Any liability to U.K. stamp duty or stamp
       duty reserve tax on the transfer of such Unionamerica ADSs to MMI will be
       borne by MMI. No U.K. stamp duty or stamp duty reserve tax will be
       payable on the issue of MMI Common Stock to a U.S. Resident.
 
           Dividends. Dividends, if any, paid on MMI Common Stock to a U.S.
       Resident will not be subject to U.K. tax in the hands of the U.S.
       Resident unless the U.S. Resident carries on business in the U.K. through
       a branch or agency to which the MMI Common Stock is attributable or,
       subject to certain exceptions, the U.S. Resident is also resident in the
       U.K for tax purposes.
 
    U.S. TAXATION.  In the opinion of Paul, Weiss, Rifkind, Wharton & Garrison,
special U.S. tax counsel to Unionamerica, on the basis of facts, representations
and assumptions set forth or referred to in such opinion, the following are the
material U.S. federal income tax consequences applicable to Unionamerica
Securityholders who are U.S. Residents who beneficially own Unionamerica ADSs as
capital assets (a "U.S. Holder"). The term "U.S. Resident" means a Person that
is any of the following: (i) a citizen of the U.S.; (ii) a resident alien for
U.S. federal income tax purposes; (iii) a corporation, partnership or other
entity created or organized in or under the laws of the U.S. or any political
subdivision thereof; or (iv) an estate or trust the income of which is subject
to U.S. federal income taxation regardless of source and that is not resident in
the U.K. for tax purposes. The discussion of U.S. tax consequences is based on
laws, regulations, rulings, and decisions in effect on the date hereof, all of
which are subject to change (possibly with retroactive effect) and differing
interpretations. This discussion is for general information only, and does not
address all aspects of U.S. federal taxation that may be applicable to a
Unionamerica Securityholder subject to special treatment under the IRC,
including banks, tax-exempt organizations, insurance companies, dealers in
securities or foreign currency, and holders who are not U.S. Persons (as defined
in Section 7701(a)(30) of the IRC). In addition, such discussion does not
address the state, local, or foreign tax consequences of the Proposed
Acquisition. Each Unionamerica Securityholder and Option holder considering the
Offer is urged to consult its tax advisor with respect to the U.S. federal,
state, local and foreign tax consequences of the Proposed Acquisition.
 
    The Proposed Acquisition will be treated as a "reorganization" within the
meaning of section 368(a)(1)(B) of the IRC, which entails the following material
U.S. federal income tax consequences to a U.S. Holder.
 
    A U.S. Holder will not recognize any gain or loss on the exchange of its
Unionamerica ADSs for MMI Common Stock except in respect of cash received in
exchange for a fractional share of MMI Common Stock (as discussed below). The
aggregate adjusted tax basis of the shares of MMI Common Stock received in the
exchange will be equal to the aggregate adjusted tax basis of the Unionamerica
ADSs surrendered therefor, and the holding period of such MMI Common Stock will
include the holding period during which such Unionamerica ADSs were held. If the
U.S. Holder has differing bases or holding periods in respect of its
Unionamerica ADSs, it should consult its tax advisor prior to the exchange with
regard to identifying the bases or holding periods of the particular shares of
MMI Common Stock received in the exchange.
 
    Cash received in exchange for a fractional share of MMI Common Stock will be
treated as received in a sale of such fractional share, and gain or loss will be
recognized equal to the difference between the amount of cash received and the
portion of the basis of the Unionamerica ADS allocable to such fractional
 
                                       71
<PAGE>
interest. Such gain or loss will be capital gain or loss, and will be long-term
capital gain or loss if the holding period for such Unionamerica ADS was more
than one year as of the date of the exchange. For individuals, gain on the
exchange will be taxed at rates that vary depending upon whether the holding
period was one year or less, more than one year but not more than 18 months, or
more than 18 months.
 
    Further, Section 367(b)(1) of the IRC will apply to an exchange by a U.S.
Holder of securities of Unionamerica (a foreign corporation) for those of MMI (a
domestic corporation). Accordingly, each U.S. Holder that realizes gain or
income in the Proposed Acquisition must notify the IRS on or before the due date
for filing a U.S. federal income tax return (taking extensions into account) for
its taxable year in which the income is realized. The notice is filed with the
IRS office with which the U.S. Holder would be required to file a U.S. federal
income tax return for the year. If a return is actually filed, the notice must
be attached to the return. Treasury regulations under Section 367 of the IRC
prescribe detailed information that must be included in the notice.
 
    Distributions, if any, paid with respect to MMI Common Stock to a former
Unionamerica Securityholder will be treated as ordinary dividend income to the
extent of MMI's current or accumulated earnings and profits, then as a return of
capital to the extent of tax basis, and then as gain from the sale of stock. In
the case of corporate holders, such distributions, to the extent they are
treated as ordinary dividend income, will generally qualify for a
dividends-received deduction of 70% of the amount of the dividend. Unlike
distributions on Unionamerica ADSs, distributions on MMI Common Stock will not
be subject to the provisions of the Treaty that address refunds of U.K. advance
corporation tax.
 
    Unless a U.S. Holder complies with certain reporting or certification
procedures or is an "exempt recipient" (i.e., in general, corporations and
certain other entities), the U.S. Holder may be subject to withholding tax of
31% with respect to any cash payments received pursuant to the Proposed
Acquisition. A foreign holder should consult its tax advisor with respect to the
application of withholding rules to it with respect to any cash payments
received pursuant to the Proposed Acquisition.
 
MATERIAL CONTRACTS BETWEEN MMI AND UNIONAMERICA
 
    In each of the past three years, Unionamerica Insurance Company Limited, a
Subsidiary of Unionamerica, has entered into reinsurance contracts with ACIC and
ACLIC, Subsidiaries of MMI. Unionamerica is a participant on the first and
second layers of MMI's Healthcare System Reinsurance Program and Physicians'
Excess of Loss Reinsurance Program and MMI's Medical Expense Catastrophe
Reinsurance Agreement.
 
    Premiums ceded to Unionamerica pursuant to these contracts were $2.6 million
in 1996, $2.5 million in 1995 and $2.1 million in 1994. Reinsurance receivables
from Unionamerica on case and incurred but not reported reserves were $5.6
million as of June 30, 1997.
 
    The Acquisition Agreement is the only other material agreement entered into
between MMI and Unionamerica during the past three years.
 
                                       72
<PAGE>
          UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION
 
    The unaudited pro forma condensed combined financial information for each of
the years in the three year period ended December 31, 1996 and for each of the
six month periods ended June 30, 1996 and 1997 is derived from the historical
financial statements of MMI and Unionamerica incorporated by reference in this
Prospectus. The accompanying unaudited condensed combined balance sheet combines
the unaudited balance sheets of MMI and Unionamerica as of June 30, 1997. The
unaudited condensed combined statements of income combine the audited statements
of income for MMI and Unionamerica for each of the years in the three year
period ended as of December 31, 1996 as well as the unaudited statements of
income for the six month periods ended June 30, 1997 and 1996.
 
    The pro forma combined financial information does not purport to represent
what the combined financial position or results of operations actually would
have been if the Proposed Acquisition had been completed at the beginning of the
periods presented or which may be obtained in the future. The information
presented below should be read in conjunction with the historical financial
statements of MMI and Unionamerica incorporated by reference in this Prospectus.
 
    The pro forma financial information has been prepared assuming the Proposed
Acquisition is accounted for as a pooling-of-interests. Under the
pooling-of-interests method of accounting, the historical financial statements
of the combined companies are retroactively combined (after elimination of
intercompany transactions) as if the companies had always operated as a single
entity. The pro forma condensed combined statements of income are prepared
assuming the pooling of interests transaction occurred at the beginning of the
earliest period presented, and the pro forma condensed combined balance sheet is
prepared assuming the transaction occurred on the balance sheet date. The
unaudited pro forma condensed combined financial information has been included
as required by the rules of the Commission and is provided for comparative
purposes only.
 
                                       73
<PAGE>
                              MMI COMPANIES, INC.
                   PRO FORMA CONDENSED COMBINED BALANCE SHEET
                                 JUNE 30, 1997
                                 (IN THOUSANDS)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                             MMI      UNIONAMERICA     PRO FORMA
                                          COMPANIES,    HOLDINGS     ADJUSTMENTS &   PRO FORMA
                                             INC.         PLC        ELIMINATIONS     COMBINED
                                          ----------  ------------   -------------   ----------
<S>                                       <C>         <C>            <C>             <C>
                                            ASSETS
  Cash and investments
    Fixed maturities....................  $  683,211    $394,480        $            $1,077,691
    Equity securities...................      49,555       3,268                         52,823
    Cash and short-term investments.....      33,333      20,102                         53,435
                                          ----------  ------------   -------------   ----------
                                             766,099     417,850         --           1,183,949
  Other assets
    Premiums and fees receivable........      85,426     163,991                        249,417
    Reinsurance recoverable on unpaid
      losses............................     108,488     158,266         (5,569)(a)     261,185
    Accrued investment income...........      10,702       5,898                         16,600
    Deferred income taxes...............      48,166      --                             48,166
    Other...............................      69,170      36,976           (833)(b)     105,313
                                          ----------  ------------   -------------   ----------
                                          $1,088,051    $782,981        $(6,402)     $1,864,630
                                          ----------  ------------   -------------   ----------
                                          ----------  ------------   -------------   ----------
 
                                LIABILITIES, MINORITY INTERESTS
                                   AND STOCKHOLDERS' EQUITY
  Liabilities
    Policy liabilities
      Loss and loss adjustment expense
        reserves........................  $  631,928    $512,296        $(5,569)(a)  $1,138,655
      Unearned premium reserves.........      83,474      90,556           (833)(b)     173,197
      Future life policy benefits.......       8,569      --                              8,569
                                          ----------  ------------   -------------   ----------
                                             723,971     602,852         (6,402)      1,320,421
    Accrued expenses and other
      liabilities.......................      16,210      16,392                         32,602
    Insurance balances payable..........      26,671      16,578                         43,249
    Long term debt(d)...................      58,000      35,000                         93,000
                                          ----------  ------------   -------------   ----------
                                             824,852     670,822         (6,402)      1,489,272
 
  Minority interest.....................      --           1,277                          1,277
 
  Stockholders' equity
    Common Stock........................       1,165         378            328(c)        1,871
    Other...............................     262,034     110,504           (328)(c)     372,210
                                          ----------  ------------   -------------   ----------
                                             263,199     110,882         --             374,081
                                          ----------  ------------   -------------   ----------
                                          $1,088,051    $782,981        $(6,402)     $1,864,630
                                          ----------  ------------   -------------   ----------
                                          ----------  ------------   -------------   ----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       74
<PAGE>
                              MMI COMPANIES, INC.
                PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME
                         SIX MONTHS ENDED JUNE 30, 1997
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                                               MMI      UNIONAMERICA     PRO FORMA
                                                           COMPANIES,     HOLDINGS     ADJUSTMENTS &    PRO FORMA
                                                              INC.           PLC        ELIMINATIONS    COMBINED
                                                           -----------  -------------  --------------  -----------
<S>                                                        <C>          <C>            <C>             <C>
Revenues
  Insurance premiums earned..............................   $  78,311     $  64,448      $              $ 142,759
  Consulting and fee income..............................      25,308        --                            25,308
  Net investment income..................................      23,288        13,692                        36,980
  Realized gains (losses) on investments.................       1,630          (660)                          970
                                                           -----------  -------------       -------    -----------
    Total revenues.......................................     128,537        77,480          --           206,017
 
Losses and expenses
  Losses and loss adjustment expenses....................      64,358        39,409                       103,767
  Insurance and administrative expenses..................      47,555        24,458                        72,013
  Interest expense.......................................       1,778         1,138                         2,916
                                                           -----------  -------------       -------    -----------
    Total losses and expenses............................     113,691        65,005          --           178,696
                                                           -----------  -------------       -------    -----------
    Income from continuing operations before income taxes
      and extraordinary loss.............................      14,846        12,475          --            27,321
Income taxes.............................................       1,326         4,288                         5,614
                                                           -----------  -------------       -------    -----------
    Income from continuing operations before
      extraordinary loss.................................      13,520         8,187          --            21,707
Extraordinary loss, net of income taxes..................      --               267                           267
                                                           -----------  -------------       -------    -----------
  Income from continuing operations......................   $  13,520     $   7,920      $   --         $  21,440
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
Income from continuing operations before extraordinary
  loss per common
  and common equivalent share............................   $    1.13     $    0.93                     $    1.12
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Income from continuing operations per common and common
  equivalent share.......................................   $    1.13     $    0.90                     $    1.11
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Weighted average number of common and common
  equivalent shares outstanding..........................      12,007         8,838          (1,449)       19,396
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       75
<PAGE>
                              MMI COMPANIES, INC.
                PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME
                         SIX MONTHS ENDED JUNE 30, 1996
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                                               MMI      UNIONAMERICA     PRO FORMA
                                                           COMPANIES,     HOLDINGS     ADJUSTMENTS &    PRO FORMA
                                                              INC.           PLC        ELIMINATIONS    COMBINED
                                                           -----------  -------------  --------------  -----------
<S>                                                        <C>          <C>            <C>             <C>
Revenues
  Insurance premiums earned..............................   $  81,824     $  67,230      $              $ 149,054
  Consulting and fee income..............................      15,628        --                            15,628
  Net investment income..................................      21,653        13,863                        35,516
  Realized gains on investments..........................       1,002           186                         1,188
                                                           -----------  -------------       -------    -----------
    Total revenues.......................................     120,107        81,279          --           201,386
Losses and expenses
  Losses and loss adjustment expenses....................      67,725        43,106                       110,831
  Insurance and administrative expenses..................      35,786        22,416                        58,202
  Interest expense.......................................       1,602         1,392                         2,994
                                                           -----------  -------------       -------    -----------
    Total losses and expenses............................     105,113        66,914          --           172,027
                                                           -----------  -------------       -------    -----------
    Income from continuing operations before income
      taxes..............................................      14,994        14,365          --            29,359
Income taxes.............................................       1,235         4,803                         6,038
                                                           -----------  -------------       -------    -----------
    Income from continuing operations....................   $  13,759     $   9,562      $   --         $  23,321
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
Income from continuing operations per common
  and common equivalent share............................   $    1.34     $    1.10                     $    1.33
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Weighted average number of common and common
  equivalent shares outstanding..........................      10,276         8,725          (1,431)       17,570
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       76
<PAGE>
                              MMI COMPANIES, INC.
                PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME
                          YEAR ENDED DECEMBER 31, 1996
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                                               MMI      UNIONAMERICA     PRO FORMA
                                                           COMPANIES,     HOLDINGS     ADJUSTMENTS &    PRO FORMA
                                                              INC.           PLC        ELIMINATIONS    COMBINED
                                                           -----------  -------------  --------------  -----------
<S>                                                        <C>          <C>            <C>             <C>
Revenues
  Insurance premiums earned..............................   $ 164,409    $   116,982     $              $ 281,391
  Consulting and fee income..............................      34,535        --                            34,535
  Net investment income..................................      44,274         29,407                       73,681
  Realized losses on investments.........................         (40)          (850)                        (890)
                                                           -----------  -------------       -------    -----------
    Total revenues.......................................     243,178        145,539         --           388,717
 
Losses and expenses
  Losses and loss adjustment expenses....................     135,786         72,990                      208,776
  Insurance and administrative expenses..................      77,026         41,383                      118,409
  Interest expense.......................................       3,397          2,686                        6,083
                                                           -----------  -------------       -------    -----------
    Total losses and expenses............................     216,209        117,059         --           333,268
                                                           -----------  -------------       -------    -----------
    Income from continuing operations before income
      taxes..............................................      26,969         28,480         --            55,449
Income taxes.............................................         854          9,375                       10,229
                                                           -----------  -------------       -------    -----------
    Income from continuing operations....................   $  26,115    $    19,105     $   --         $  45,220
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
Income from continuing operations per common
  and common equivalent share............................   $    2.42    $      2.18                    $    2.50
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Weighted average number of common and common
  equivalent shares outstanding..........................      10,770          8,754         (1,436)       18,088
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       77
<PAGE>
                              MMI COMPANIES, INC.
                PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME
                          YEAR ENDED DECEMBER 31, 1995
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                                               MMI      UNIONAMERICA     PRO FORMA
                                                           COMPANIES,     HOLDINGS     ADJUSTMENTS &    PRO FORMA
                                                              INC.           PLC        ELIMINATIONS    COMBINED
                                                           -----------  -------------  --------------  -----------
<S>                                                        <C>          <C>            <C>             <C>
Revenues
  Insurance premiums earned..............................   $ 155,191    $   117,712     $              $ 272,903
  Consulting and fee income..............................      22,336        --                            22,336
  Net investment income..................................      39,850         23,086                       62,936
  Realized gains on investments..........................       1,367            325                        1,692
                                                           -----------  -------------       -------    -----------
    Total revenues.......................................     218,744        141,123         --           359,867
Losses and expenses
  Losses and loss adjustment expenses....................     130,088         76,220                      206,308
  Insurance and administrative expenses..................      61,055         39,402                      100,457
  Interest expense.......................................       2,767          6,605                        9,372
                                                           -----------  -------------       -------    -----------
    Total losses and expenses............................     193,910        122,227         --           316,137
                                                           -----------  -------------       -------    -----------
 
    Income from continuing operations before income taxes
      and extraordinary loss.............................      24,834         18,896         --            43,730
Income taxes.............................................       2,139          5,943                        8,082
                                                           -----------  -------------       -------    -----------
    Income from continuing operations before
      extraordinary loss.................................      22,695         12,953         --            35,648
Extraordinary loss, net of income taxes..................      --              4,737                        4,737
                                                           -----------  -------------       -------    -----------
  Income from continuing operations......................   $  22,695    $     8,216     $   --         $  30,911
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
Income from continuing operations before extraordinary
  loss per common
  and common equivalent share............................   $    2.34    $      2.28                    $    2.46
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Income from continuing operations per common and common
  equivalent share.......................................   $    2.34    $      1.34                    $    2.12
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Weighted average number of common and common
  equivalent shares outstanding..........................       9,683          5,018           (823)       13,878
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       78
<PAGE>
                              MMI COMPANIES, INC.
                PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME
                          YEAR ENDED DECEMBER 31, 1994
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   UNAUDITED
 
<TABLE>
<CAPTION>
                                                               MMI      UNIONAMERICA     PRO FORMA
                                                           COMPANIES,     HOLDINGS     ADJUSTMENTS &    PRO FORMA
                                                              INC.           PLC        ELIMINATIONS    COMBINED
                                                           -----------  -------------  --------------  -----------
<S>                                                        <C>          <C>            <C>             <C>
Revenues
  Insurance premiums earned..............................   $ 132,389    $   135,587     $              $ 267,976
  Consulting and fee income..............................      18,602        --                            18,602
  Net investment income..................................      29,067         22,083                       51,150
  Realized losses on investments.........................      (2,853)       (32,408)                     (35,261)
                                                           -----------  -------------       -------    -----------
    Total revenues.......................................     177,205        125,262         --           302,467
 
Losses and expenses
  Losses and loss adjustment expenses....................     112,711         87,743                      200,454
  Insurance and administrative expenses..................      47,286         40,775                       88,061
  Interest expense.......................................       1,619          7,003                        8,622
                                                           -----------  -------------       -------    -----------
    Total losses and expenses............................     161,616        135,521         --           297,137
                                                           -----------  -------------       -------    -----------
    Income (loss) from continuing operations
      before income taxes................................      15,589        (10,259)        --             5,330
Income taxes (credit)....................................         538         (3,468)                      (2,930)
                                                           -----------  -------------       -------    -----------
    Income (loss) from continuing operations.............   $  15,051    $    (6,791)    $   --         $   8,260
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
Income (loss) from continuing operations per
  common and common equivalent share.....................   $    1.72    $     (1.85)                   $    0.54
                                                           -----------  -------------                  -----------
                                                           -----------  -------------                  -----------
Weighted average number of common and common
  equivalent shares outstanding..........................       8,763          4,464           (732)       12,495
                                                           -----------  -------------       -------    -----------
                                                           -----------  -------------       -------    -----------
</TABLE>
 
       See notes to unaudited pro forma condensed financial information.
 
                                       79
<PAGE>
NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION
 
(a) To eliminate loss and loss adjustment expense reserves ceded to Unionamerica
    Insurance Company Limited by ACIC, a Subsidiary of MMI. Pro forma
    adjustments to the income statement to eliminate the effect of reinsurance
    of ACIC by Unionamerica are not necessary because the income statement is
    presented net of reinsurance and there is no material difference in the
    carrying values of reinsurance balances between ACIC and Unionamerica.
 
(b) To eliminate the effect of unearned premium reserves ceded by ACIC to
    Unionamerica Insurance Company Limited.
 
(c) To adjust the pro forma aggregate par value of outstanding MMI Common Stock
    to reflect the conversion of Unionamerica ADSs to 0.836 shares of MMI Common
    Stock per Unionamerica ADS.
 
(d) In July 1997, Unionamerica made a $7.5 million investment in Jago Managing
    Agency Limited that was financed with bank debt and seller notes. Following
    the closing of the Proposed Acquisition, MMI may retire both its own and
    Unionamerica's bank debt, which totalled $93 million as of June 30, 1997,
    with approximately $100 million of proceeds from a preferred trust
    securities offering.
 
                                       80
<PAGE>
                                 LEGAL MATTERS
 
    The validity of the shares of MMI Common Stock to be issued in connection
with the Offer will be passed upon for MMI by Wildman, Harrold, Allen & Dixon,
Chicago, Illinois. In addition, certain U.S. income tax matters will be passed
upon by Paul, Weiss, Rifkind, Wharton & Garrison, New York, New York, special
U.S. tax counsel to Unionamerica, and certain U.K. income tax matters will be
passed upon by Lovell White Durrant, London, England, U.K. counsel to
Unionamerica.
 
                                    EXPERTS
 
    The consolidated financial statements and schedules of MMI Companies, Inc.
and Subsidiaries at December 31, 1996 and 1995, and for each of the three years
in the period ended December 31, 1996, incorporated by reference in this
Prospectus and Registration Statement, have been audited by Ernst & Young LLP,
independent auditors, as set forth in their reports thereon incorporated by
reference herein. Such consolidated financial statements and schedules are
incorporated herein by reference in reliance upon such reports given upon the
authority of such firm as experts in accounting and auditing.
 
    The consolidated financial statements and schedules of Unionamerica Holdings
plc and Subsidiaries at December 31, 1996, and for the year ended December 31,
1996, incorporated by reference in this Prospectus and Registration Statement
have been audited by KPMG Audit Plc, Chartered Accountants and Registered
Auditors, as set forth in their reports thereon. The consolidated financial
statements and schedules of Unionamerica Holdings plc and Subsidiaries at
December 31, 1995, and for each of the two years in the period ended December
31, 1995, incorporated by reference in this Prospectus and Registration
Statement have been audited by KPMG, Chartered Accountants and Registered
Auditors, as set forth in their reports thereon. Such consolidated financial
statements and schedules are included in reliance upon such reports given upon
the authority of such firms as experts in accounting and auditing.
 
                                       81
<PAGE>
                                   APPENDIX A
 
                             ACQUISITION AGREEMENT
                           DATED AS OF JUNE 25, 1997
                                 BY AND BETWEEN
                              MMI COMPANIES, INC.
                                      AND
                           UNIONAMERICA HOLDINGS PLC
<PAGE>
                             ACQUISITION AGREEMENT
                           DATED AS OF JUNE 25, 1997
                                 BY AND BETWEEN
                              MMI COMPANIES, INC.
                                      AND
                           UNIONAMERICA HOLDINGS PLC
<PAGE>
                               TABLE OF CONTENTS
 
    This Table of Contents is not part of the Agreement to which it is attached
but is inserted for convenience only.
 
<TABLE>
<CAPTION>
                                                                                                       PAGE NO.
                                                                                                      -----------
<S>          <C>                                                                                      <C>
 
ARTICLE I
COMPANY AUTHORIZATIONS AND GOVERNANCE
 
1.01         Company Actions........................................................................      APP-A-1
1.02         Company Board Representation; Section 14(f)............................................      APP-A-1
 
ARTICLE II
CLOSING
2.01         Closing................................................................................      APP-A-2
 
ARTICLE III
EXCHANGE OF SHARES
3.01         Exchange of Company Common Stock.......................................................      APP-A-2
3.02         Acquisition of Remaining Company Capital Stock.........................................      APP-A-3
 
ARTICLE IV
REPRESENTATIONS AND WARRANTIES OF THE COMPANY
4.01         Organization and Qualification.........................................................      APP-A-4
4.02         Capital Stock..........................................................................      APP-A-4
4.03         Authority Relative to this Agreement...................................................      APP-A-5
4.04         Non-Contravention; Approvals and Consents..............................................      APP-A-5
4.05         SEC Reports and Financial Statements...................................................      APP-A-6
4.06         Absence of Certain Changes or Events...................................................      APP-A-6
4.07         Absence of Undisclosed Liabilities.....................................................      APP-A-7
4.08         Legal Proceedings......................................................................      APP-A-7
4.09         Information Supplied...................................................................      APP-A-7
4.10         Compliance with Laws and Orders........................................................      APP-A-8
4.11         Compliance with Agreements; Certain Agreements.........................................      APP-A-8
4.12         Taxes..................................................................................      APP-A-9
4.13         Employee Benefit Plans.................................................................     APP-A-14
4.14         Labor Matters..........................................................................     APP-A-15
4.15         Opinion of Financial Advisor...........................................................     APP-A-15
4.16         Related Party Transactions.............................................................     APP-A-16
4.17         Assets; Real Property..................................................................     APP-A-16
4.18         Intellectual Property..................................................................     APP-A-16
4.19         Material Contracts and Relationships...................................................     APP-A-17
4.20         Absence of Certain Business Practices..................................................     APP-A-18
4.21         Books and Records......................................................................     APP-A-18
4.22         Information Regarding Acquisitions.....................................................     APP-A-18
 
ARTICLE V
REPRESENTATIONS AND WARRANTIES OF BUYER
5.01         Organization and Qualification.........................................................     APP-A-19
5.02         Capital Stock..........................................................................     APP-A-19
5.03         Authority Relative to this Agreement...................................................     APP-A-20
</TABLE>
 
                                       i
<PAGE>
<TABLE>
<CAPTION>
                                                                                                       PAGE NO.
                                                                                                      -----------
<S>          <C>                                                                                      <C>
5.04         Non-Contravention; Approvals and Consents..............................................     APP-A-20
5.05         SEC Reports and Financial Statements...................................................     APP-A-21
5.06         Absence of Certain Changes or Events...................................................     APP-A-21
5.07         Absence of Undisclosed Liabilities.....................................................     APP-A-21
5.08         Legal Proceedings......................................................................     APP-A-21
5.09         Information Supplied...................................................................     APP-A-22
5.10         Compliance with Laws and Orders........................................................     APP-A-22
5.11         Compliance with Agreements; Certain Agreements.........................................     APP-A-23
5.12         Taxes..................................................................................     APP-A-23
5.13         Employee Benefit Plans; ERISA..........................................................     APP-A-25
5.14         Labor Matters..........................................................................     APP-A-25
5.15         Vote Required..........................................................................     APP-A-25
5.16         Ownership of Company Common Stock......................................................     APP-A-25
 
ARTICLE VI
COVENANTS OF THE COMPANY
6.01         Covenants of the Company...............................................................     APP-A-26
6.02         No Solicitations.......................................................................     APP-A-28
6.03         Tax Covenants of the Company...........................................................     APP-A-28
6.04         Approval of Company Stockholders.......................................................     APP-A-28
 
ARTICLE VII
COVENANTS OF BUYER
7.01         Covenants of Buyer.....................................................................     APP-A-29
7.02         Tax Covenants of Buyer.................................................................     APP-A-30
 
ARTICLE VIII
ADDITIONAL AGREEMENTS
8.01         Access to Information; Confidentiality.................................................     APP-A-30
8.02         Preparation of Proxy Statement and Registration Statement by Buyer.....................     APP-A-30
8.03         Approval of Stockholders...............................................................     APP-A-31
8.04         Regulatory and Other Approvals.........................................................     APP-A-31
8.05         Employment and Severance Agreement.....................................................     APP-A-31
8.06         Directors' and Officers' Indemnification and Insurance.................................     APP-A-31
8.07         Fees and Expenses......................................................................     APP-A-32
8.08         Brokers or Finders.....................................................................     APP-A-32
8.09         Takeover Statutes......................................................................     APP-A-32
8.10         Conveyance Taxes.......................................................................     APP-A-32
8.11         Notice.................................................................................     APP-A-33
8.12         Fulfillment of Conditions..............................................................     APP-A-33
8.13         Representation on Buyer's Board of Directors...........................................     APP-A-33
8.14         Selling Stockholders Undertaking.......................................................     APP-A-33
8.15         Affiliates Agreement...................................................................     APP-A-33
 
ARTICLE IX
CONDITIONS
9.01         Mutual Conditions to Closing...........................................................     APP-A-34
9.02         Conditions to Buyer's Obligation.......................................................     APP-A-35
9.03         Additional Conditions to Closing.......................................................     APP-A-37
</TABLE>
 
                                       ii
<PAGE>
<TABLE>
<CAPTION>
                                                                                                       PAGE NO.
                                                                                                      -----------
<S>          <C>                                                                                      <C>
 
ARTICLE X
TERMINATION, AMENDMENT AND WAIVER
10.01        Termination............................................................................     APP-A-37
10.02        Effect of Termination..................................................................     APP-A-38
10.03        Amendment..............................................................................     APP-A-38
10.04        Waiver.................................................................................     APP-A-38
 
ARTICLE XI
THE OFFER
11.01        The Offer..............................................................................     APP-A-39
11.02        Company Actions........................................................................     APP-A-40
 
ARTICLE XII
GENERAL PROVISIONS
12.01        Non-Survival of Representations, Warranties, Covenants and Agreements..................     APP-A-41
12.02        Notices................................................................................     APP-A-41
12.03        Entire Agreement; Incorporation of Exhibits............................................     APP-A-42
12.04        Public Announcements...................................................................     APP-A-43
12.05        No Third Party Beneficiary.............................................................     APP-A-43
12.06        No Assignment; Binding Effect..........................................................     APP-A-43
12.07        Headings...............................................................................     APP-A-43
12.08        Invalid Provisions.....................................................................     APP-A-43
12.09        Governing Law..........................................................................     APP-A-43
12.10        Enforcement of Agreement...............................................................     APP-A-43
12.11        Certain Definitions....................................................................     APP-A-43
12.12        Counterparts...........................................................................     APP-A-47
Exhibit A    Form of Undertaking
Exhibit B    Form of Affiliates Agreement
</TABLE>
 
                                      iii
<PAGE>
                             ACQUISITION AGREEMENT
 
    This ACQUISITION AGREEMENT dated as of June 25, 1997 (this "Agreement") is
made and entered into by and between MMI COMPANIES, INC., a corporation
organized under the laws of Delaware ("Buyer"), and UNIONAMERICA HOLDINGS PLC, a
corporation organized under the laws of England and Wales (the "Company").
 
    WHEREAS, the Boards of Directors of Buyer and the Company have each
determined that it is advisable and in the best interests of their respective
stockholders to consummate, and have approved, the business combination
transactions provided for herein whereby the Company shall become a wholly owned
subsidiary of Buyer pursuant to the acquisition by Buyer, solely for voting
common stock of Buyer, of all of the American Depository Shares ("ADSs"),
representing all of the ordinary shares, nominal value $0.0448 per share, of the
Company (such ADSs being referred to as "Company Common Stock"), and all of the
deferred stock of the Company, par value L1 per share (the "Company Deferred
Stock"), through (i) the Offer and (ii) the subsequent compulsory acquisition of
any remaining shares of Company Common Stock solely for voting common stock of
Buyer (collectively, the "Transaction");
 
    WHEREAS, the parties intend that the exchange of shares of Company Common
Stock and Company Deferred Stock for shares of common stock, par value $0.10 per
share, of Buyer ("Common Stock") pursuant to the Offer will be treated as a
transaction described in Section 368(a)(1)(B) of the Internal Revenue Code of
1986, as amended (the "Code"); and
 
    WHEREAS, Buyer and the Company desire to make certain representations,
warranties and agreements in connection with the transactions contemplated by
this Agreement and also to prescribe various conditions to the consummation of
such transactions.
 
    NOW, THEREFORE, in consideration of the mutual covenants and agreements set
forth in this Agreement, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:
 
                                   ARTICLE I
                     COMPANY AUTHORIZATIONS AND GOVERNANCE
 
    1.01.  COMPANY ACTIONS.  The Company hereby approves and consents to the
Offer and the other transactions contemplated by this Agreement and represents
that the Board of Directors of the Company, at a meeting duly called and held,
has unanimously:
 
        (a) determined that this Agreement and the transactions contemplated
    hereby, including the Offer, are fair to and in the best interests of the
    holders of shares of Company Common Stock; and
 
        (b) agreed to recommend that the stockholders of the Company accept the
    Offer, if commenced, and tender their shares of Company Common Stock and
    Company Deferred Stock thereunder to Buyer, subject to the conditions and
    exceptions set forth herein.
 
    1.02.  COMPANY BOARD REPRESENTATION; SECTION 14(F).
 
        (a) Subject to compliance with the laws of England and Wales, the
    Company's Memorandum and Articles of Association and other applicable law,
    promptly upon the exchange by Buyer of Common Stock for shares of Company
    Common Stock and Company Deferred Stock pursuant to the Offer, and from time
    to time thereafter, (i) Buyer shall be entitled to designate four persons
    ("Buyer's Designees") to be included on the Board of Directors of the
    Company and (ii) the Company shall, upon request by Buyer, promptly satisfy
    the foregoing entitlement by using its best efforts to cause Buyer's
    Designees promptly to be so elected or appointed.
 
        (b) The Company's obligations to appoint Buyer's Designees to the Board
    of Directors of the Company shall be subject to Section 14(f) of the
    Securities Exchange Act of 1934, as amended (such
 
                                    APP-A-1
<PAGE>
    Act and the rules and regulations promulgated thereunder being referred to
    herein as the "Exchange Act") and Rule 14f-1 promulgated thereunder, if
    applicable. The Company shall promptly take all actions required pursuant to
    such Section and Rule in order to fulfill its obligations under this
    Section, and shall include in the Schedule 14D-9 such information with
    respect to the Company and its officers and directors as is required under
    such Section and Rule to fulfill such obligations. Buyer shall supply to the
    Company and be solely responsible for any information with respect to either
    of them and their designees, officers, directors and affiliates required by
    such Section 14(f) and Rule 14f-1.
 
                                   ARTICLE II
                                    CLOSING
 
    2.01  CLOSING.  Unless this Agreement shall have been terminated and the
transactions herein contemplated shall have been abandoned pursuant to Section
10.01, the closing of the Offer, including the prior declaration that the Offer
has become unconditional (the "Closing"), will take place at the offices of
Wildman, Harrold, Allen & Dixon, 225 West Wacker Drive, Chicago, Illinois 60606
on a date to be specified by Buyer, which shall be no later than the fifth
business day following the date on which all the conditions set forth in Article
IX have been satisfied or waived, unless another date, time or place is agreed
to in writing by the parties hereto (the "Closing Date").
 
                                  ARTICLE III
                               EXCHANGE OF SHARES
 
    3.01  EXCHANGE OF COMPANY COMMON STOCK.
 
        (a)  EXCHANGE AGENT.  As of the Closing, Buyer shall deposit with
    ChaseMellon Shareholder Services L.L.C. or such other bank or trust company
    designated by Buyer (and reasonably acceptable to the Company) (the
    "Exchange Agent"), for delivery to the former holders of shares of Company
    Common Stock and Company Deferred Stock, for exchange in accordance with
    this Article III, through the Exchange Agent, certificates representing the
    shares of Common Stock issuable in exchange for outstanding shares of
    Company Common Stock and Company Deferred Stock tendered and not properly
    withdrawn pursuant to the Offer (such shares of Common Stock being
    hereinafter referred to as the "Exchange Fund"). The Exchange Agent shall
    agree to deliver such shares as contemplated by this Section 3.01 and upon
    such additional terms as may be agreed upon by the Exchange Agent, the
    Company and Buyer. The Exchange Fund shall not be used for any purpose
    except as expressly provided in this Agreement.
 
        (b)  EXCHANGE PROCEDURES.  At the same time as and with the mailing of
    Offer Documents pursuant to Section 11.01, the Exchange Agent shall cause to
    be mailed to each holder of record of an American Depositary Receipt or
    Receipts which represent outstanding shares of Company Common Stock (the
    "Company Certificates") whose shares will be exchanged solely for shares of
    Common Stock, (i) a letter of transmittal (which shall specify that delivery
    shall be effected, and risk of loss and title to the Company Certificates
    shall pass, only upon receipt of the Company Certificates by the Exchange
    Agent and shall be in such form and have such other provisions as Buyer and
    the Company may reasonably specify) and (ii) instructions for use in
    effecting the surrender of the Company Certificates in exchange for
    certificates representing shares of Common Stock. Upon Closing, the holder
    of such Company Certificate who has properly tendered shall be entitled to
    receive in exchange therefor a certificate representing that number of whole
    shares of Common Stock which such holder has the right to receive pursuant
    to this Section 3.01. In the event of a transfer of ownership of Company
    Common Stock which is not registered in the transfer records of the Company
    and the Depositary, a certificate representing the proper number of shares
    of Common Stock may be issued to a transferee if the Company Certificate
    representing such Company Common Stock is presented to the Exchange Agent,
    accompanied by all documents required to evidence and effect such transfer,
    in
 
                                    APP-A-2
<PAGE>
    form and substance satisfactory to Buyer, and by evidence that any
    applicable stock transfer taxes and fees have been paid.
 
        (c)  NO FRACTIONAL SHARES.
 
           (i) No certificates or scrip representing fractional shares of Common
       Stock shall be issued upon the surrender for exchange of Company
       Certificates, and such fractional share interests will not entitle the
       owner thereof to vote or to any rights of a stockholder of Buyer.
 
           (ii) As promptly as practicable following the Closing, the Exchange
       Agent shall determine the excess of (x) the number of full shares of
       Common Stock delivered to the Exchange Agent by Buyer pursuant to Section
       3.01(a) over (y) the aggregate number of full shares of Common Stock to
       be distributed to holders of Company Common Stock pursuant to Section
       3.01(b) (such excess being herein called the "Excess Shares"). As soon
       after the Closing as practicable, the Exchange Agent, as agent for the
       former holders of Company Common Stock, shall sell the Excess Shares at
       then prevailing prices on the New York Stock Exchange, Inc. (the "NYSE"),
       all in the manner provided in paragraph (iii) of this Section 3.01.
 
           (iii) The sale of the Excess Shares by the Exchange Agent shall be
       executed on the NYSE through one or more member firms of the NYSE and
       shall be executed in round lots to the extent practicable. Until the net
       proceeds of such sale or sales have been distributed to the former
       holders of Company Common Stock, the Exchange Agent will hold such
       proceeds in trust for the former holders of Company Common Stock (the
       "Excess Shares Trust"). All commissions, transfer taxes and other
       out-of-pocket transaction costs, including the expenses and compensation,
       of the Exchange Agent incurred in connection with such sale of the Excess
       Shares, shall be paid out of the Excess Shares Trust. The Exchange Agent
       shall determine the portion of the Excess Shares Trust to which each
       former holder of Company Common Stock shall be entitled, if any, by
       multiplying the amount of the aggregate net proceeds comprising the
       Excess Shares Trust by a fraction the numerator of which is the amount of
       the fractional share interest to which such former holder of Company
       Common Stock is entitled and the denominator of which is the aggregate
       amount of fractional share interests to which all former holders of
       Company Common Stock are entitled.
 
           (iv) As soon as practicable after the determination of the amount of
       cash, if any, to be paid to former holders of Company Common Stock in
       respect of any fractional share interests of Common Stock, the Exchange
       Agent shall make available such amounts to such former holders of Company
       Common Stock.
 
        (d)  NO LIABILITY.  Neither Buyer nor the Company shall be liable to any
    holder of shares of Company Common Stock, Company Deferred Stock or Common
    Stock, as the case may be, for such shares (or dividends or distributions
    with respect thereto) or cash from the Excess Shares Trust delivered to a
    public official pursuant to any applicable abandoned property, escheat or
    similar law.
 
    3.02  ACQUISITION OF REMAINING COMPANY CAPITAL STOCK.
 
        (a)  COMPANY COMMON STOCK.  Following the Closing, if sufficient
    acceptances have been received, Buyer shall be entitled to apply the
    provisions of Sections 428 to 430F of the United Kingdom Companies Act 1985
    to acquire compulsorily any outstanding shares of Company Common Stock.
 
        (b)  COMPANY DEFERRED STOCK.  At the Closing, the Company shall, in
    accordance with Article 5 of the Articles of Association of the Company,
    cause all of the issued and outstanding shares of Company Deferred Stock to
    be transferred to such Person other than Buyer as Buyer may designate to
    hold such shares as nominee for Buyer in exchange for one share of Common
    Stock for each 25,000 shares of Company Deferred Stock.
 
                                    APP-A-3
<PAGE>
                                   ARTICLE IV
                 REPRESENTATIONS AND WARRANTIES OF THE COMPANY
 
    The Company represents and warrants to Buyer as follows:
 
    4.01  ORGANIZATION AND QUALIFICATION.  The Company is a corporation duly
incorporated and validly existing under the laws of England and Wales. Each of
the Company's Subsidiaries is listed on Schedule 4.01 to this Agreement. Each
such Subsidiary is duly incorporated and validly existing under the laws of
England and Wales and each of the Company and its Subsidiaries has full
corporate power and authority to conduct its business as and to the extent now
conducted and to own, use and lease its assets and properties, except for such
failures to be so incorporated, created and existing or to have such power and
authority which, individually or in the aggregate, are not having and could not
be reasonably expected to have a material adverse effect on the Company and its
Subsidiaries taken as a whole. Each of the Company and its Subsidiaries is duly
qualified, licensed or admitted to do business in each jurisdiction in which the
ownership, use or leasing of its assets and properties, or the conduct or nature
of its business, makes such qualification, licensing or admission necessary,
except for such failures to be so qualified, licensed or admitted which,
individually or in the aggregate, are not having and could not be reasonably
expected to have a material adverse effect on the Company and its Subsidiaries
taken as a whole. Except for beneficial interests in the Subsidiaries of the
Company and as disclosed in Schedule 4.01 to this Agreement, the Company and the
Subsidiaries do not directly or indirectly own any equity or similar interest
in, or any interest convertible into or exchangeable or exercisable for, any
equity or similar interest in, any corporation, partnership, joint venture,
business trust or other business association or Person. The Company has
previously delivered to Buyer correct and complete copies of the memorandum and
articles of association (or other comparable charter documents) of the Company
and each of its Subsidiaries.
 
    4.02  CAPITAL STOCK.
 
        (a) The authorized capital stock of the Company consists solely of
    20,000,000 shares of Company Common Stock and 50,000 shares of Company
    Deferred Stock. As of the date hereof and as of the Closing (except as
    otherwise permitted in Section 6.01(b)(ii)(C)), 8,443,969 shares of Company
    Common Stock were, and will be, issued and outstanding, and no shares were
    reserved for issuance except as set forth in Schedule 4.02 to this
    Agreement. Prior to the Closing, except as set forth in Schedule 4.02 to
    this Agreement, there will be no change in the number of issued and
    outstanding shares of Company Common Stock or shares of Company Common Stock
    reserved for issuance. As of the date hereof and as of the Closing, 50,000
    shares of Company Deferred Stock were, and will be, issued and outstanding
    and no shares were reserved for issuance. No bonds, debentures, notes or
    other instruments or evidence of indebtedness having the right to vote (or
    convertible into, or exercisable or exchangeable for, securities having the
    right to vote) on any matters on which the Company's stockholders may vote
    ("Company Voting Debt") are issued or outstanding. All of the issued and
    outstanding shares of Company Common Stock and Company Deferred Stock are,
    and all shares reserved for issuance will be, upon issuance in accordance
    with the terms specified in the instruments or agreements pursuant to which
    they are issuable, duly authorized, validly issued, fully paid and
    nonassessable. Except pursuant to this Agreement and except as set forth in
    Schedule 4.02 to this Agreement, there are no outstanding subscriptions,
    options, warrants, calls, rights (including "phantom" stock rights),
    preemptive rights or other contracts, commitments, understandings or
    arrangements, including any right of conversion or exchange under any
    outstanding security, instrument or agreement (together, "Options"),
    obligating the Company or any of its Subsidiaries to issue or sell any
    Company Voting Debt or shares of capital stock or other securities of the
    Company or to grant, extend or enter into any Option with respect thereto.
 
        (b) Except as disclosed in Schedule 4.02 to this Agreement, all of the
    outstanding beneficial interests of each Subsidiary of the Company are
    owned, beneficially and of record, by the Company or a Subsidiary wholly
    owned, directly or indirectly, by the Company, as described on Schedule 4.01
    to
 
                                    APP-A-4
<PAGE>
    this Agreement, free and clear of any liens, claims, mortgages,
    encumbrances, pledges, security interests, equities and charges of any kind
    (each a "Lien"). Except as disclosed in Schedule 4.02 to this Agreement,
    there are no (i) outstanding Options obligating the Company or any of its
    Subsidiaries to issue or sell any beneficial or other ownership interest of
    any Subsidiary of the Company or to grant, extend or enter into any such
    Option or (ii) voting trusts, proxies or other commitments, understandings,
    restrictions or arrangements in favor of any Person other than the Company
    or a Subsidiary wholly owned, directly or indirectly, by the Company with
    respect to the voting of or the right to participate in dividends or other
    earnings on any beneficial or other ownership interest of any Subsidiary of
    the Company.
 
        (c) Except as disclosed in Schedule 4.02 to this Agreement, there are no
    outstanding contractual obligations of the Company or any Subsidiary of the
    Company to repurchase, redeem or otherwise acquire any shares of Company
    Common Stock, Company Deferred Stock or any beneficial or other ownership
    interest of any Subsidiary of the Company or to provide funds to, or make
    any investment (in the form of a loan, capital contribution or otherwise)
    in, any Subsidiary of the Company or any other Person.
 
    4.03  AUTHORITY RELATIVE TO THIS AGREEMENT.  The Company has full corporate
power and authority to enter into this Agreement and to perform its obligations
hereunder and to consummate the transactions contemplated hereby. The execution,
delivery and performance of this Agreement by the Company and the consummation
by the Company of the transactions contemplated hereby have been duly and
validly approved by the Board of Directors of the Company and no other corporate
proceedings on the part of the Company or its stockholders are necessary to
authorize the execution, delivery and performance of this Agreement by the
Company and the consummation by the Company of the transactions contemplated
hereby. This Agreement has been duly and validly executed and delivered by the
Company and constitutes a legal, valid and binding obligation of the Company
enforceable against the Company in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency, reorganization,
moratorium or other similar laws affecting the enforcement of creditors' rights
generally and by general equitable principles (regardless of whether such
enforceability is considered in a proceeding in equity or at law).
 
    4.04.  NON-CONTRAVENTION; APPROVALS AND CONSENTS.
 
        (a) Except as disclosed in Schedule 4.04(a) to this Agreement, the
    execution and delivery of this Agreement by the Company do not, and the
    performance by the Company of its obligations hereunder and the consummation
    of the transactions contemplated hereby will not, conflict with, result in a
    violation or breach of, constitute (with or without notice or lapse of time
    or both) a default under, result in or give to any Person any right of
    payment or reimbursement, termination, cancellation, modification or
    acceleration of, or result in the loss of a material benefit under, or
    result in the creation or imposition of any Lien upon any of the assets or
    properties of the Company or any of its Subsidiaries under, any of the
    terms, conditions or provisions of (i) the memorandum and articles of
    association (or other comparable charter documents) of the Company or any of
    its Subsidiaries, or (ii) any statute, law, rule, regulation or ordinance
    (together, "laws"), or any judgment, decree, order, writ, permit or license
    (together, "orders"), of any court, tribunal, arbitrator, authority, agency,
    commission, official or other instrumentality of the United States, the
    United Kingdom, or any state, county, city or other political subdivision
    thereof, or the NYSE (a "Governmental or Regulatory Authority") applicable
    to the Company or any of its Subsidiaries or any of their respective assets
    or properties, or (iii) any note, bond, mortgage, security agreement,
    indenture, license, franchise, permit, concession, contract, lease or other
    instrument, obligation or agreement of any kind to which the Company or any
    of its Subsidiaries is a party or by which the Company or any of its
    Subsidiaries or any of their respective assets or properties is bound
    (together, "Contracts"), or (iv) the Disclosed Scheme, excluding from the
    foregoing clauses (ii) and (iii) conflicts, violations, breaches, defaults,
    terminations, modifications, accelerations and creations and impositions of
    Liens which, individually or in the aggregate, could not be reasonably
    expected to have a material adverse effect on the Company and its
 
                                    APP-A-5
<PAGE>
    Subsidiaries taken as a whole, or on the ability of the Company to
    consummate the transactions contemplated by this Agreement.
 
        (b) Except (i) for the filing of the Schedule 14D-9 with the Securities
    and Exchange Commission (the "SEC") pursuant to the Exchange Act, (ii) the
    filing, if applicable, of a premerger notification report by the Company
    under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended,
    and the rules and regulations thereunder (the "HSR Act"), (iii) the consents
    set forth in Section 9.01(e), and (iv) as disclosed in Schedule 4.04(b) to
    this Agreement, no consent, approval or action of, filing with or notice to
    any Governmental or Regulatory Authority or other public or private third
    party is necessary or required under any of the terms, conditions or
    provisions of any law or order of any Governmental or Regulatory Authority
    or any Contract to which the Company or any of its Subsidiaries is a party
    or by which the Company or any of its Subsidiaries or any of their
    respective assets or properties is bound for the execution and delivery of
    this Agreement by the Company, the performance by the Company of its
    obligations hereunder or the consummation of the transactions contemplated
    by this Agreement, other than such consents, approvals, actions, filings and
    notices which the failure to make or obtain, as the case may be,
    individually or in the aggregate, could not be reasonably expected to have a
    material adverse effect on the Company and its Subsidiaries taken as a
    whole, or on the ability of the Company to consummate the transactions
    contemplated by this Agreement.
 
    4.05  SEC REPORTS AND FINANCIAL STATEMENTS.  The Company delivered to Buyer
prior to the execution of this Agreement a true and complete copy of each form,
report, schedule, registration statement, definitive proxy statement and other
document (together with all amendments thereof and supplements thereto) filed by
the Company or any of its Subsidiaries with the SEC since January 1, 1995 (as
such documents have since the time of their filing been amended or supplemented,
the "Company SEC Reports"), which are all the documents (other than preliminary
material) that the Company and its Subsidiaries were required to file with the
SEC since such date, and all such filings have been timely made. As of their
respective dates, the Company SEC Reports (i) complied as to form in all
material respects with the requirements of the Securities Act of 1933, as
amended, and the rules and regulations thereunder (the "Securities Act"), or the
Exchange Act, as the case may be, and (ii) did not contain any untrue statement
of a material fact or omit to state a material fact required to be stated
therein or necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading. The audited
consolidated financial statements and unaudited interim consolidated financial
statements (including, in each case, the notes, if any, thereto) included in the
Company SEC Reports (the "Company Financial Statements") complied as to form in
all material respects with the published rules and regulations of the SEC with
respect thereto, were prepared in accordance with United States generally
accepted accounting principles applied on a consistent basis during the periods
involved (except as may be indicated therein or in the notes thereto and except
with respect to unaudited statements as permitted by Form 10-Q or the SEC) and
fairly and accurately present (subject, in the case of the unaudited interim
financial statements, to normal, recurring year-end audit adjustments (which are
not expected to be, individually or in the aggregate, materially adverse in
amount or effect to the Company and its Subsidiaries taken as a whole)) the
consolidated financial position of the Company and its consolidated subsidiaries
at the respective dates thereof and the consolidated results of their operations
and cash flows for the respective periods then ended. Except as set forth in
Schedule 4.05 to this Agreement, each Subsidiary of the Company is treated as a
consolidated subsidiary of the Company in the Company Financial Statements for
all periods covered thereby.
 
    4.06  ABSENCE OF CERTAIN CHANGES OR EVENTS.  Except as disclosed in the
Company SEC Reports filed prior to the date of this Agreement, (a) other than a
reasonably foreseeable change, event or development affecting the Company
resulting from the execution of this Agreement or the transactions contemplated
hereby, since December 31, 1996 there has not been any change, event or
development having, or that could be reasonably expected to have, individually
or in the aggregate, a material adverse effect on the
 
                                    APP-A-6
<PAGE>
Company and its Subsidiaries taken as a whole, or on the ability of the Company
to consummate the transactions contemplated by this Agreement, and (b) except as
disclosed in Schedule 4.06 to this Agreement, since such date (i) the Company
and its Subsidiaries have conducted their respective businesses only in the
ordinary course consistent with past practice and (ii) neither the Company nor
any of its Subsidiaries has taken any action which, if taken after the date
hereof, would constitute a breach of any provision of clause (ii) of Section
6.01(b).
 
    4.07  ABSENCE OF UNDISCLOSED LIABILITIES.  Except for matters reflected or
reserved against in the balance sheet for the period ended December 31, 1996
included in the Company Financial Statements or as disclosed in Schedule 4.07 to
this Agreement, neither the Company nor any of its Subsidiaries had at such
date, or has incurred since that date, any liabilities or obligations (whether
absolute, accrued, contingent, fixed or otherwise, or whether due or to become
due) of any nature that would be required by United States generally accepted
accounting principles to be reflected on a consolidated balance sheet of the
Company and its consolidated subsidiaries (including the notes thereto), except
liabilities or obligations (i) which were incurred in the Ordinary Course of
Business and (ii) which have not been, and could not be reasonably expected to
be, individually or in the aggregate, materially adverse to the Company and its
Subsidiaries taken as a whole.
 
    4.08  LEGAL PROCEEDINGS.  Except as specifically disclosed in the Company
SEC Reports filed prior to the date of this Agreement or in Schedule 4.08 to
this Agreement, (i) there are no actions, suits, arbitrations or proceedings
pending or, to the knowledge of the Company or any of its Subsidiaries,
threatened against, relating to or affecting, nor to the knowledge of the
Company or any of its Subsidiaries are there any Governmental or Regulatory
Authority investigations or audits pending or threatened against, relating to or
affecting, the Company or any of its Subsidiaries or any of their respective
assets and properties which, individually or in the aggregate, is having or
could be reasonably expected to have a material adverse effect on the Company
and its Subsidiaries taken as a whole or on the ability of the Company to
consummate the transactions contemplated by this Agreement and (ii) neither the
Company nor any of its Subsidiaries is subject to any order of any Governmental
or Regulatory Authority which, individually or in the aggregate, is having or
could be reasonably expected to have a material adverse effect on the Company
and its Subsidiaries taken as a whole, or on the ability of the Company to
consummate the transactions contemplated by this Agreement.
 
    4.09  INFORMATION SUPPLIED.
 
        (a) The Schedule 14D-9 and any other documents to be filed by the
    Company with the SEC or any other Governmental or Regulatory Authority in
    connection with the transactions contemplated by this Agreement will not, on
    the date of its filing or, with respect to the Schedule 14D-9, at the date
    it is filed with the SEC and first published, sent or given to the Company's
    stockholders, or, in the case of any document mailed to the Company's
    stockholders by the Company, at the date it is mailed to stockholders of the
    Company, contain any untrue statement of a material fact or omit to state
    any material fact required to be stated therein or necessary in order to
    make the statements therein, in light of the circumstances under which they
    are made, not misleading, except that no representation is made by the
    Company with respect to information supplied in writing by or on behalf of
    Buyer expressly for inclusion therein and information incorporated by
    reference therein from documents filed by Buyer or any of its Subsidiaries
    with the SEC. The Schedule 14D-9 and any such other documents filed by the
    Company with the SEC under the Exchange Act in connection with the
    transactions contemplated by this Agreement will comply as to form in all
    material respects with the requirements of the Exchange Act.
 
        (b) Neither the information supplied or to be supplied in writing by or
    on behalf of the Company or any of its Subsidiaries for inclusion, nor the
    information incorporated by reference from documents filed by the Company or
    any of its Subsidiaries with the SEC, in the Offer Documents or any other
    documents to be filed by Buyer with the SEC or any other Governmental or
    Regulatory Authority or
 
                                    APP-A-7
<PAGE>
    delivered to Buyer's stockholders in connection with the transactions
    contemplated by this Agreement will on the date of its filing or, with
    respect to the Offer Documents or any other documents published and/or
    delivered to the Company's stockholders by the Company or the Buyer's
    stockholders by the Buyer, on the date they are filed with the SEC and first
    published, sent or given to stockholders, contain any untrue statement of a
    material fact or omit to state any material fact required to be stated
    therein or necessary in order to make the statements therein, in light of
    the circumstances under which they are made, not misleading.
 
    4.10  COMPLIANCE WITH LAWS AND ORDERS.  The Company and its Subsidiaries
hold all permits, licenses, variances, exemptions, orders and approvals of all
Governmental and Regulatory Authorities necessary for the lawful conduct of
their respective businesses (the "Company Permits"), and all material Company
Permits are listed on Schedule 4.10 to this Agreement, except for failures to
hold such permits, licenses, variances, exemptions, orders and approvals which,
individually or in the aggregate, are not having and could not be reasonably
expected to have a material adverse effect on the Company and its Subsidiaries
taken as a whole or on the ability of the Company to consummate the transactions
contemplated by this Agreement. The Company and its Subsidiaries are in
compliance with the terms of the Company Permits, except failures so to comply
which, individually or in the aggregate, are not having and could not be
reasonably expected to have a material adverse effect on the Company and its
Subsidiaries taken as a whole, or on the ability of the Company to consummate
the transactions contemplated by this Agreement. Except as disclosed in the
Company SEC Reports filed prior to the date of this Agreement, neither the
Company nor any of its Subsidiaries are in violation of or default under any law
or order of any Governmental or Regulatory Authority, except for such violations
or defaults which, individually or in the aggregate, are not having and could
not be reasonably expected to have a material adverse effect on the Company and
its Subsidiaries taken as a whole, or on the ability of the Company to
consummate the transactions contemplated by this Agreement. For purposes of this
Section 4.10 and Schedule 4.10 to this Agreement, Company Permits shall not
include the permits, licenses, variances, exemptions, orders and approvals
referred to in Article IX.
 
    4.11  COMPLIANCE WITH AGREEMENTS; CERTAIN AGREEMENTS.
 
        (a) Except as disclosed in the Company SEC Reports filed prior to the
    date of this Agreement, neither the Company nor any of its Subsidiaries nor,
    to the knowledge of the Company or any of its Subsidiaries, any other party
    thereto is in breach or violation of, or in default in the performance or
    observance of any term or provision of, and no event has occurred which,
    with notice or lapse of time or both, could be reasonably expected to result
    in a default under, (i) the memorandum and articles of association (or other
    comparable charter documents) of the Company or any of its Subsidiaries or
    (ii) any Contract to which the Company or any of its Subsidiaries is a party
    or by which the Company or any of its Subsidiaries or any of their
    respective assets or properties is bound, except in the case of clause (ii)
    for breaches, violations and defaults which, individually or in the
    aggregate, are not having and could not be reasonably expected to have a
    material adverse effect on the Company and its Subsidiaries taken as a
    whole.
 
        (b) Except as disclosed in Schedule 4.11 to this Agreement or in the
    Company SEC Reports filed prior to the date of this Agreement or as provided
    for in this Agreement, as of the date hereof, neither the Company nor any of
    its Subsidiaries is a party to any oral or written (i) consulting agreement
    not terminable on 30 days' or less notice, (ii) union or collective
    bargaining agreement, (iii) agreement with any executive officer or other
    key employee of the Company or any of its Subsidiaries the benefits of which
    are contingent or vest, or the terms of which are materially altered, upon
    the occurrence of a transaction involving the Company or any of its
    Subsidiaries of the nature contemplated by this Agreement, (iv) agreement
    with respect to any executive officer or other key employee of the Company
    or any of its Subsidiaries providing any term of employment or compensation
    guarantee, (v) agreement or plan, including any stock option, stock
    appreciation right, restricted stock or stock purchase plan, any of the
    benefits of which will be increased, or the vesting of the
 
                                    APP-A-8
<PAGE>
    benefits of which will be accelerated, by the occurrence of any of the
    transactions contemplated by this Agreement, or the value of any of the
    benefits of which will be calculated on the basis of any of the transactions
    contemplated by this Agreement or (vi) Contract which is material to any of
    their operations taken as a whole or could have a material adverse effect on
    the ability of the Company to consummate the transactions contemplated by
    this Agreement or could reasonably be expected to result in a material
    adverse effect on the Company and its Subsidiaries after the consummation of
    the transactions contemplated by this Agreement.
 
    4.12  TAXES.  The representations and warranties contained in this Section
4.12 are given subject to the matters disclosed in Schedule 4.12 to this
Agreement.
 
        (a)  DEFINITIONS.  The following terms shall have the following meanings
    for purposes of this Section 4.12 and Schedule 4.12 to this Agreement:
 
            (i) "Balance Sheet Date" means December 31, 1996.
 
            (ii) "Event" means the winding up or dissolution of any Person, and
       any act, transaction or omission whatsoever, and any reference to an
       event occurring on or before a particular date shall include events which
       for Tax purposes are deemed to have, or are treated or regarded as
       having, occurred on or before that date.
 
           (iii) "Group Relief" means Relief surrendered or claimed pursuant to
       Chapter IV of Part X of the Taxes Act.
 
            (iv) "Relief" means, unless the context otherwise requires, any
       allowance, credit, deduction, exemption or set-off in respect of any Tax
       or relevant to the computation of any income, profits or gains for the
       purposes of any Tax; and (A) any reference to the "use" or "set off" of
       Relief shall be construed accordingly and shall include use or set off in
       part; and (B) any reference to the "loss" of a Relief shall include the
       absence or non-existence of any such Relief, or to such Relief being
       available only in a reduced amount.
 
            (v) "Tax" means corporation tax, advance corporation tax, income tax
       (including income tax or amounts on account of income tax required to be
       deducted or withheld from or accounted for in respect of any payment),
       capital gains tax, payroll tax, development land tax, inheritance tax,
       VAT, national insurance contributions, capital duty, stamp duty, stamp
       duty reserve tax, duties of customs and excise, petroleum revenue tax,
       local authority rates and charges, all taxes, duties or charges replaced
       by or replacing any of them, and all other taxes or similar impost on
       gross or net income, profits or gains, distributions, receipts, sales,
       use, occupation, franchise, value added and personal property, taxes on
       premiums (whether calculated on the gross or net amount thereof), and all
       levies, imposts, duties, charges or withholdings of any nature whatsoever
       chargeable by any Tax Authority, and any payment whatsoever which the
       Company may be or become bound to make to any Person as a result of the
       discharge by that Person of any Tax which the Company has failed to
       discharge, together with all penalties, charges and interest relating to
       any of the foregoing or to any late or incorrect return (or failure to
       file such return or other form or statement) in respect of any of them,
       and regardless of whether any such taxes, levies, duties, imposts,
       charges, withholdings, penalties and interest are chargeable directly or
       primarily against or attributable directly or primarily to the Company or
       any other Person and of whether any amount in respect of any of them is
       recoverable from any other Person.
 
            (vi) "Tax Authority" means any taxing or other authority (whether
       within or outside the United Kingdom, including the United States or any
       State) competent to impose any Tax liability.
 
           (vii) "Taxes Act" means the Income and Corporation Taxes Act 1988 of
       the United Kingdom.
 
          (viii) "VAT" means value added tax, being the Tax created and
       administered by and according to the VAT Legislation.
 
                                    APP-A-9
<PAGE>
            (ix) "VAT Legislation" shall include the Value Added Tax Act 1994
       and all other enactments in relation to VAT and all notices, provisions
       and conditions made or issued thereunder, including the terms of any
       written agreement reached with HM Customs & Excise or any concession
       disclosed to Buyer in writing prior to the date of this Agreement.
 
            (x) Any reference to income, profits or gains "earned", "accrued" or
       "received" on or before a particular date or in respect of a particular
       period shall include income, profits or gains which for Tax purposes are
       deemed to have been or are treated or regarded as earned, accrued or
       received on or before that date or in respect of that period.
 
            (xi) Any reference to something occurring (including a Tax liability
       arising) "in the ordinary course of business" shall, without prejudice to
       the generality thereof, be deemed not to include:
 
               (A) anything which results in the Company receiving a valid Tax
           claim in respect of any liability to Tax of, or properly attributable
           to, another Person (other than the Company);
 
               (B) anything which relates to or involves the acquisition or
           disposal of an asset or the supply of services (including the lending
           of money, or the hiring or licensing of tangible or intangible
           property) in a transaction which is not entered into on arm's length
           terms;
 
               (C) anything which relates to or involves the making of a
           distribution for Tax purposes, the creation, cancellation or
           reorganization of share or loan capital, the creation, cancellation
           or repayment of any intra-group debt or any company becoming or
           ceasing or being treated as ceasing to be a member of a group of
           companies or as becoming or ceasing to be associated or connected
           with any other company for any Tax purposes; or
 
               (D) anything which relates to a transaction or arrangement which
           includes, or a series of transactions or arrangements which includes,
           any step or steps having no commercial or business purpose apart from
           the reduction, avoidance or deferral of a Tax liability.
 
           (xii) Persons shall be treated as "connected" for the purposes of
       this Section 4.12 if they are connected within the meaning of Section 839
       of the Taxes Act.
 
          (xiii) References to any provision of an enactment include any
       provision re-enacted by such provision.
 
        (b)  GENERAL/COMPLIANCE.
 
            (i) All material liabilities, whether actual, current, deferred,
       contingent or disputed, of the Company for Tax measured by reference to
       income, profits or gains earned, accrued or received (or premiums earned,
       accrued or received) on or before the Balance Sheet Date, or arising in
       respect of an Event occurring or deemed to occur on or before the Balance
       Sheet Date, are, where required, provided for or (as appropriate)
       disclosed or have otherwise been taken into account in (A) the Company
       Financials for the year ended December 31, 1996 (the "1996 Company
       Financials") in accordance with UK Accounting Standards and the
       accounting policies set out in the 1996 Company Financials and (B) the
       Company's Annual Report on Form 10-K for the year ended December 31, 1996
       in accordance with United States generally accepted accounting principles
       and the accounting policies set out in the Company's financial statements
       ("U.S. Company Financials"). Taxes which may arise from held over gains
       from intragroup transactions under Section 171 of the Taxation and
       Chargeable Gains Act of 1992 of the United Kingdom (the "Act of 1992"),
       which may become due under Section 179 of the Act of 1992 as a result of
       the transaction contemplated in this Agreement or otherwise, have either
       been provided for or will be provided for in the 1996 Company Financials
       or the U.S. Company Financials, or do not exist. All other warranties
       relating to specific Tax matters set out in this Section 4.12 are made
       without prejudice to the generality of the foregoing.
 
                                    APP-A-10
<PAGE>
            (ii) Since the Balance Sheet Date:
 
               (A) the Company has not been involved in any transaction which
           has given or may give rise to a liability to Tax on the Company (or
           would have given or might give rise to such a liability but for the
           availability of any Relief) other than Tax in respect of transactions
           entered into by it in the ordinary course of business; and
 
               (B) no accounting period (as defined in Section 12 of the Taxes
           Act) of the Company has ended as referred to in Section 12(3) of the
           Taxes Act.
 
           (iii) The Company has duly, and within any appropriate time limits,
       made all returns, given all notices and supplied all other forms,
       statements and information (each, a "Return") required to be supplied to
       all relevant Tax Authorities. All such Returns were and remain, to the
       knowledge of the Company, true, complete and correct in all material
       respects and were made on a proper basis and do not, and to the knowledge
       of the Company are not likely to, reveal any transactions which may be
       the subject of any dispute with any Tax Authority. The Company is neither
       involved in any current dispute with any Tax Authority nor is it (nor has
       it in the last seven (7) years been) the subject of any formal
       investigation, formal audit or non-routine visit by any Tax Authority.
       The Company has not been informed in writing of any planned formal
       investigation, formal audit or non-routine visit by any Tax Authority
       and, to the knowledge of the Company, there are no facts which are likely
       to cause such an investigation, audit or non-routine visit to be
       instituted in respect of the Company. Within the past seven (7) years,
       neither the Company nor, to the knowledge of the Company, any director or
       officer of the Company (in his/ her capacity as such) has paid or become
       liable to pay, and to the knowledge of the Company there are no
       circumstances by reason of which it or they may become liable to pay, to
       any Tax Authority, any penalty, fine, surcharge or interest in respect of
       any Tax (including in respect of any failure to make, give or supply any
       Return to any relevant Tax Authority, or any failure to pay Tax on the
       due date for payment).
 
            (iv) No Tax Authority has operated or agreed to operate any special
       arrangement (being an arrangement which departs from any relevant
       legislation or any published practice or concession) in relation to the
       Company's affairs.
 
            (v) The Company has not made, nor is there in effect with respect to
       the Company, an election pursuant to sections 953(c)(3)(C) or 953(d) of
       the Code. The Company has not been, and has no reason to believe that it
       will be, characterized as a "passive foreign investment corporation" (as
       defined in Section 1291 et seq. of the Code).
 
            (vi) Prior to the date of this Agreement, the Company has disclosed
       to Buyer material details of all computations and Reliefs which were
       taken into account in preparing the provisions for Tax or deferred Tax in
       the 1996 Company Financials. No Relief has been claimed by and/or
       surrendered or given to the Company and/or taken into account in
       determining or eliminating any provision for Tax or deferred Tax in the
       1996 Company Financials, which, to the knowledge of the Company, is not
       validly available to the Company and the Company is not aware of (or, if
       it is aware of, has fully disclosed to Buyer) any challenge made by, or
       grounds for a challenge available to, a Tax Authority in relation
       thereto.
 
           (vii) Except as disclosed in Schedules 4.12(b) and 4.12(c) to this
       Agreement, the Company has made all deductions and retentions of or on
       account of Tax as it was or is obliged or entitled to make, and all such
       payments of or on account of Tax as should have been made to any Tax
       Authority in respect of such deductions or retentions have been made.
 
          (viii) Except for payment of dividends and payments of or on account
       of Taxes, capital payments, fees paid in connection with the transactions
       contemplated by this Agreement and revenue payments made in accordance
       with the Company's 1997 Business Plan and recognized as
 
                                    APP-A-11
<PAGE>
       falling into a category which are not so deductible, the Company is not
       obliged to make nor has it since the Balance Sheet Date made a payment
       which will not be deductible for the purposes of calculating its
       liability to corporation tax.
 
            (ix) Except as disclosed on Schedule 4.12(c) to this Agreement, no
       event has occurred which could result in the Company becoming liable for
       Tax which is primarily or directly chargeable against or attributable to
       a person other than the Company or which is charged by reference to the
       income, profits or gains of another Person.
 
        (c)  EMPLOYEES/PENSIONS.  All United Kingdom National Insurance
    contributions and sums payable to the Inland Revenue under the P.A.Y.E.
    system and any amounts of a corresponding nature payable to any foreign Tax
    Authority due and payable by the Company up to the date hereof have been
    paid, and, to the knowledge of the Company, the Company has made all such
    deductions and retentions as should have been made under section 203 of the
    Taxes Act and all regulations made thereunder or under any comparable laws
    or regulations of any relevant foreign jurisdiction, including United States
    Federal and State wage withholding, Social Security and other similar
    systems.
 
        (d)  GROUP RELIEF.
 
            (i) The Company has disclosed to Buyer in writing prior to the date
       of this Agreement full, accurate and complete details of all arrangements
       or agreements to which the Company is a party or which in any way affect
       the Company and which relate to Group Relief and of any such arrangements
       or agreements under which any claim could be made by any Person either
       for the surrender to it or by it to the Company of Group Relief or for
       the making or repayment of any payment in relation to Group Relief.
 
            (ii) The Company is not a dual resident investing company within the
       meaning of Section 404 of the Taxes Act. The Company is not, and at no
       time within the seven (7) years immediately preceding the date of this
       Agreement has been, a close company as defined in Section 414 of the
       Taxes Act.
 
        (e)  CONTROLLED FOREIGN COMPANIES.  The Company has not received any
    notice of the making of a direction under Section 747 of the Taxes Act and
    no circumstances exist which would entitle the Inland Revenue to make such a
    direction and to apportion to the Company any profits of a controlled
    foreign company pursuant to Section 752 of the Taxes Act.
 
        (f)  COMPANY RESIDENCE, TREASURY CONSENTS AND MIGRATION.  The Company is
    and has at all times in the seven (7) years immediately preceding the date
    of this Agreement been accepted by the UK Inland Revenue as resident in the
    United Kingdom for Tax purposes and is not and has not been treated for the
    purposes of any double taxation arrangements having effect by virtue of
    Section 788 of the Taxes Act or for any other Tax purpose as resident in any
    other jurisdiction (including the conduct of the affairs of the Company so
    as to be engaged in a United States trade or business through a permanent
    establishment within the meaning of Article 5 of the Convention Between the
    Government of the United States of America and the Government of the United
    Kingdom of Great Britain and Northern Ireland for the Avoidance of Double
    Taxation and the Prevention of Fiscal Evasion with Respect to Taxes on
    Income and Capital Gains), nor is the Company nor has it been directly
    subject to Tax in any other jurisdiction, except for United States Federal
    excise taxes imposed under Section 4371 et seq. of the Code in the
    circumstances described in Schedule 4.12 to this Agreement. The Company has
    not carried out or caused or permitted to be carried out any of the
    transactions specified at the relevant time in Section 765(1) of the Taxes
    Act otherwise than with the prior consent of HM Treasury (and, in the case
    of a special consent, full particulars of which have been disclosed to Buyer
    in writing prior to the date hereof; and any conditions subject to which
    such consent was given have been complied with in full) or specified at the
    relevant time in Section 765A of the Taxes Act without having duly provided
    the required information to the Inland Revenue.
 
                                    APP-A-12
<PAGE>
        (g)  VALUE ADDED TAX.
 
            (i) This Section 4.12(g) shall apply, with appropriate
       modifications, to any equivalent sales or turnover tax in any
       jurisdiction other than the United Kingdom to which the Company is
       subject.
 
            (ii) The Company:
 
               (A) is registered for the purposes of VAT, has been so registered
           at all times that it has been required to be registered by VAT
           Legislation, and such registration is not subject to any conditions
           imposed by or agreed with HM Customs & Excise; and has complied fully
           with and observed in all material respects the terms of VAT
           Legislation;
 
               (B) has maintained and obtained all the records, invoices and
           other documents (as the case may be) required by the VAT Legislation
           and has preserved such records, invoices and other documents in such
           form and for such periods as are required by VAT Legislation;
 
               (C) is a member of a group for VAT purposes but is not the
           representative member of that group;
 
               (D) is not and has not been subject under VAT Legislation to any
           penalty liability notice, written warning of failure to comply,
           surcharge liability notice or requirement to give security as a
           condition of making taxable supplies.
 
           (iii) In respect of each of the assets of the Company (if any) which
       is a capital item for the purpose of Part XV of the Value Added Tax
       Regulations 1995, the Company has disclosed to Buyer in writing, prior to
       the date of this Agreement, full details of the capital item affected,
       the amount of the total input tax (within the meaning of such
       Regulations) which is subject to adjustment, the percentage of the total
       input tax which was reclaimable on the capital item in the first interval
       applicable to it and any adjustments made or to be made having regard to
       Events occurred up to the date of this Agreement, the date of acquisition
       of the capital item and the number of intervals in the adjustment period
       remaining from the date of this Agreement, and full details of all
       matters to date relevant in determining any adjustments.
 
        (h)  STAMP DUTIES.  All documents in the possession or under the control
    of the Company or to the production of which the Company is entitled which
    establish or are necessary to establish the title of the Company to any
    asset have been duly stamped and any applicable stamp duties or charges in
    respect of such documents have been duly accounted for and paid, and no such
    documents which are outside the United Kingdom would attract stamp duty if
    they were brought into the United Kingdom. The Company has no unsatisfied
    liability to stamp duty reserve tax or interest or penalties on stamp duty
    reserve tax.
 
        (i)  REORGANIZATION REPRESENTATIONS AND WARRANTIES OF THE COMPANY.
 
            (i) There is no plan or intention by the stockholders of the Company
       who own five percent or more of the Company Common Stock, and to the best
       of the knowledge of the Company, there is no plan or intention on the
       part of the remaining stockholders of the Company to sell, exchange, or
       otherwise dispose of a number of shares of Common Stock received in the
       Transaction that would reduce the Company stockholders' ownership of
       Common Stock to a number of shares having a value, as of the date of the
       Closing, of less than 50 percent of the value of all of the formerly
       outstanding stock of the Company as of the same date. For purposes of
       this representation, shares of Company Common Stock surrendered by
       Company stockholders entitled to dissenters rights, if any, or exchanged
       for cash in respect of fractional shares of Common Stock will be treated
       as outstanding Company Common Stock on the date of the Closing. Moreover,
       shares of Company Common Stock and shares of Common Stock held by the
 
                                    APP-A-13
<PAGE>
       Company stockholders and otherwise sold, redeemed, or disposed of prior
       or subsequent to the Closing will be considered in making this
       representation.
 
            (ii) The Company has no plan or intention to issue additional shares
       of its stock that would result in Buyer losing control of the Company
       within the meaning of Section 368(c) of the Code.
 
           (iii) At the time of the Closing, the Company will not have
       outstanding any warrants, options, convertible securities, or any other
       type of right pursuant to which any person could acquire stock in the
       Company that if exercised or converted, would affect Buyer's acquisition
       or retention or control of the Company, as defined in Section 368(c) of
       the Code.
 
            (iv) The Company is not an investment company as defined in Section
       368(a)(2)(F)(iii) and (iv) of the Code.
 
            (v) The Company will pay any of its stockholders, if any, entitled
       to dissenters rights the value of their stock out of its own funds. No
       funds will be supplied for that purpose, directly or indirectly, by
       Buyer, nor will Buyer directly or indirectly reimburse the Company for
       any payments to dissenters.
 
            (vi) On the date of the Closing, the fair market value of the assets
       of the Company will exceed the sum of its liabilities plus the
       liabilities, if any, to which the assets are subject.
 
           (vii) None of the compensation received by any stockholder-employees
       of the Company will be separate consideration for, or allocable to, any
       of their shares of the Company Common Stock; none of the shares of Common
       Stock received by any stockholder-employee will be separate consideration
       for, or allocable to, any employment agreement; and the compensation paid
       to any stockholder-employees will be for services actually rendered and
       will be commensurate with amounts paid to third parties bargaining at
       arm's length for similar services.
 
          (viii) The payment of cash in respect of fractional shares of Common
       Stock is solely for the purpose of avoiding the expense and inconvenience
       to Buyer of issuing fractional shares and does not represent separately
       bargained-for consideration. The total cash consideration that will be
       paid in the Transaction to the former Company stockholders instead of
       issuing fractional shares of Common Stock will not exceed one percent of
       the total consideration that will be issued in the Transaction to the
       Company stockholders in exchange for their shares of the Company Common
       Stock. The fractional share interest of each former Company stockholder
       will be aggregated and no former Company stockholder will receive cash in
       an amount equal to or greater than the value of one full share of Common
       Stock.
 
    4.13  EMPLOYEE BENEFIT PLANS.
 
        (a) For the purposes of Section 4.13:
 
            (i) "Disclosed Schemes" means each of The Unionamerica (1993)
       Pension Scheme, The Unionamerica (1993) Death Benefit Scheme and The
       Unionamerica (1993) Supplementary Death Benefit Scheme and the Personal
       Pension Schemes approved or provisionally approved for the purposes of
       either Chapter I or Chapter IV of Part XIV of the UK Income and
       Corporation Taxes Act 1988 to which contributions have been made or are
       intended to be made in respect of Hugh C. Evans, Philip M. Marcell and
       Ian G. Sinclair; and
 
            (ii) "Employee" means a director or employee or former director or
       employee of the Company or any of its Subsidiaries.
 
        (b) Complete, accurate and full particulars of each of the Disclosed
    Schemes have been given to Buyer. Except as provided for under each of the
    Disclosed Schemes, neither the Company nor any of its Subsidiaries has any
    obligation (whether legally enforceable or not) to provide or contribute to
    the provision of any "relevant benefit" (as defined in Section 612 of the UK
    Income and Corporation
 
                                    APP-A-14
<PAGE>
    Taxes Act 1988) or like benefit for or in respect of any Employee or an
    Employee's dependants and no such obligation has been announced, nor has the
    Company or any of its Subsidiaries any liability (actual or contingent) to
    contribute to the Continental Reinsurance London Pension Plan.
 
        (c) No plan, proposal or intention to amend, discontinue (in whole or in
    part) or exercise a discretion in relation to any of the Disclosed Schemes
    has been communicated to an Employee who is a member of any of the Disclosed
    Schemes.
 
        (d) All amounts due in respect of each of the Disclosed Schemes have
    been paid.
 
        (e) Each of the Disclosed Schemes has assets sufficient to discharge all
    benefits (whether or not yet payable) to its beneficiaries at the date of
    this Agreement.
 
        (f) Each of the Disclosed Schemes has at all times been operated in
    accordance with its governing documentation and in accordance with all
    applicable legal and regulatory requirements.
 
        (g) So far as the Company is aware there are no actions, claims or suits
    (other than routine claims for benefits) in progress, outstanding, pending
    or threatened against the trustees or administrators of any of the Disclosed
    Schemes or against the Company or any of its Subsidiaries in respect of any
    act, event or omission or other circumstance or matter arising out of or in
    connection with the Disclosed Schemes and so far as the Company is aware
    there is no circumstance or matter which may give rise to such a claim or
    dispute.
 
        (h) None of the Disclosed Schemes is a contracted-out scheme for the
    purposes of the Pension Schemes Act 1993.
 
        (i) None of the assets of the Disclosed Schemes are invested (directly
    or indirectly) in or loaned (directly or indirectly) to the Company or any
    of its Subsidiaries.
 
        (j) No payment or repayment of an asset of any of the Disclosed Schemes
    has been made to the Company or any of its Subsidiaries since the date of
    the most recent actuarial valuation.
 
        (k) In relation to each of the Disclosed Schemes, no relevant insolvency
    event (as defined for the purposes of the Pension Schemes Act 1993) has
    occurred in relation to any employer or former employer which participated
    in the relevant scheme on or after 1 July 1992. None of the Disclosed
    Schemes are in the process of being wound-up nor have any of the Disclosed
    Schemes been closed to new entrants.
 
        (l) No company or other legal entity currently participates in any of
    the Disclosed Schemes other than those listed in Schedule 4.13 to this
    Agreement.
 
    4.14  LABOR MATTERS.  Except as disclosed in the Company SEC Reports filed
prior to the date of this Agreement or in Schedule 4.14 to this Agreement, there
are no controversies pending or, to the knowledge of the Company, threatened
between the Company or any of its Subsidiaries and any representatives of its
employees, except as would not, individually or in the aggregate, have a
material adverse effect on the Company and its Subsidiaries taken as a whole,
and, to the knowledge of the Company, there are no material organizational
efforts presently being made involving any of the employees of the Company or
any of its Subsidiaries. There has been no work stoppage, strike or other
concerted action by employees of the Company or any of its Subsidiaries in the
ten years prior to the date hereof except as have not, individually or in the
aggregate, had a material adverse effect on the Company and its Subsidiaries
taken as a whole.
 
    4.15  OPINION OF FINANCIAL ADVISOR.  The Company has received the opinion of
Donaldson, Lufkin & Jenrette Securities Corporation, dated the date hereof, to
the effect that, as of the date hereof, the Exchange Ratio to be offered to the
stockholders of the Company is fair from a financial point of view to the
stockholders of the Company, a true and complete copy of such opinion has been
delivered to Buyer prior to the execution of this Agreement and such opinion has
not been withdrawn.
 
                                    APP-A-15
<PAGE>
    4.16  RELATED PARTY TRANSACTIONS.  Except as set forth on Schedule 4.16 to
this Agreement, there are no transactions, commitments or obligations between
the Company or any of its Subsidiaries and any holder of five percent or more of
the Company's outstanding Company Common Stock or any of such holder's
affiliates which will continue after the Closing. In addition, except as set
forth on Schedule 4.16 to this Agreement, none of the matters listed on Schedule
4.16 to this Agreement will provide to the Company assets, income, financing or
business on a basis significantly more or less favorable than that available
from unaffiliated Persons. Schedule 4.16 to this Agreement also (i) states the
amounts due from the Company or any of its Subsidiaries to any holder of five
percent or more of the Company's outstanding Company Common Stock or any of such
holder's affiliates, (ii) describes the transactions out of which such amounts
due arose and (iii) describes any interest of any holder of five percent or more
of the Company's outstanding Company Common Stock or any of such holder's
affiliates in any supplier or customer of, or any other entity that will have
business dealings with the Company or any of its Subsidiaries after the Closing.
Except as set forth on Schedule 4.16 to this Agreement, to the knowledge of the
Company neither any holder of five percent or more of the Company's outstanding
Company Common Stock or any of such holder's affiliates, nor any officer,
director or key employee (each key employee being listed on Schedule 4.16 to
this Agreement) of the Company or any of its Subsidiaries possesses, directly or
indirectly, any ownership interest in, or is a director, officer, employee or
consultant to, any corporation or other business which is a client, supplier,
customer, lessor or competitor of the Company or any of its Subsidiaries.
 
    4.17  ASSETS; REAL PROPERTY.
 
        (a) Except as set forth on Schedule 4.17 to this Agreement, the Company
    and its Subsidiaries own or have rights to use all assets (other than real
    property) necessary to permit the Company and its Subsidiaries to conduct
    their business as it is currently being conducted except where the failure
    to own or have the right to use such assets would not, individually or in
    the aggregate, have a material adverse effect on the Company and its
    Subsidiaries taken as a whole.
 
        (b) Schedule 4.17 to this Agreement identifies all the real property
    owned, leased, licensed or occupied by the Company or its Subsidiaries (the
    "Properties"). Except as set forth in Schedule 4.17 to this Agreement, (i)
    the Company is, either directly or through its Subsidiaries, the legal and
    beneficial owner of the Properties and is in sole and undisputed occupation
    of the Properties and the Properties are free from any Lien, sublease,
    tenancy or right of occupation, (ii) the Properties are not subject to any
    outgoings, other than general rates, water rates and insurance premiums and,
    in the case of leasehold properties, rent and service charges, (iii) the
    Properties are free from any local land charge, land charge, caution,
    inhibition or notice which might be regarded as materially affecting the
    value or curtailing the use of the Properties and no matter exists which is
    capable of registration against any of the Properties, (iv) the title deeds
    of the Company and each of its Subsidiaries are free from Lien and (v) the
    Company (or the relevant Subsidiary) has paid the rent and has not been
    notified of any breach of the covenants on the part of the tenant and the
    conditions contained in any leases (which expression includes underleases)
    under which the Properties are held and the Company is not aware of any such
    breach of covenant.
 
        (c) Except in relation to the interest in each Property identified in
    Schedule 4.17 to this Agreement, the Company and each Subsidiary has no
    liability (actual or contingent) arising out of a conveyance, transfer,
    lease, tenancy, license, agreement or other document relating to land,
    premises or an interest in land or premises.
 
        (d) No other Person has any interest in the Property except in the case
    of any leasehold property, any landlord holding a reversionary interest.
 
    4.18  INTELLECTUAL PROPERTY.
 
        (a) All material Intellectual Property owned or licensed by the Company
    or any of its Subsidiaries and all material licenses or similar agreements
    or arrangements to which the Company or any of its
 
                                    APP-A-16
<PAGE>
    Subsidiaries is a party (either as licensee or licensor) for each such item
    of Intellectual Property have been disclosed to Buyer.
 
        (b) Except as set forth on Schedule 4.18(b) to this Agreement:
 
            (i) The Company (or a Subsidiary of the Company as described on
       Schedule 4.18(b) to this Agreement) owns or otherwise has the right to
       use the Intellectual Property described in Section 4.18(a);
 
            (ii) There have been no actions or other judicial or adversary
       proceedings involving the Company or any or its Subsidiaries concerning
       any item of Intellectual Property, and no such action or proceeding is
       threatened;
 
           (iii) The Company (or a Subsidiary of the Company, as described on
       Schedule 4.18(b) to this Agreement) has the right and authority to use
       each item of Intellectual Property in connection with the conduct of the
       Company's (or such Subsidiary's) business in the manner presently
       conducted and such use, to the knowledge of the Company does not conflict
       with, infringe upon or violate any Intellectual Property of any other
       Person, except for insignificant matters;
 
            (iv) The Company (or such Subsidiary, as applicable) has taken
       measures it believes are adequate to protect all Confidential Information
       and proprietary information (e.g., trade secrets, including, without
       limitation, source and object codes for software); and
 
            (v) The conduct by the Company and its Subsidiaries of their
       respective businesses does not conflict, to the knowledge of the Company
       and each of its Subsidiaries with the valid patents, trademarks, service
       marks, trade secrets or trade names of others, except for insignificant
       matters.
 
    4.19  MATERIAL CONTRACTS AND RELATIONSHIPS.
 
        (a) Except for this Agreement and agreements specifically identified on
    other Schedules hereto, Schedule 4.19 to this Agreement sets forth a
    complete and correct list of the following:
 
            (i) All agreements (or groups of agreements with one or more related
       entities) between (x) the Company or any of its Subsidiaries and any
       customer (or groups of agreements with one or more related entities), and
       (y) the Company or any of its Subsidiaries and any supplier (or groups of
       agreements with one or more related entities) involving payments in
       excess of $250,000 per annum;
 
            (ii) All agreements that relate to the borrowing or lending by the
       Company or any of its Subsidiaries of any money in excess of $250,000;
 
           (iii) All agreements to which the Company or any of its Subsidiaries
       is a party that extend for a period of 30 days or more and involve
       amounts in excess of $250,000;
 
            (iv) All agreements that create or continue any material Security
       Interest against, or right of any third party with respect to, any
       material asset of the Company or any of its Subsidiaries;
 
            (v) All agreements by which the Company or any of its Subsidiaries
       leases or has the right to lease capital equipment and other personal
       property involving the Company or any of its Subsidiaries, in all such
       cases either as lessee or lessor and which require payments in excess of
       $250,000;
 
            (vi) All license agreements, whether as licensor or licensee and
       which require payments in excess of $250,000;
 
           (vii) All agreements between the Company or any of its Subsidiaries
       and any of their respective subcontractors which require payments in
       excess of $250,000; and
 
                                    APP-A-17
<PAGE>
          (viii) All other agreements to which the Company or any of its
       Subsidiaries is a party or by which any of them are bound and that
       require payment in excess of $250,000 in any twelve-month period or that
       are or may be material to the financial condition, results of operations
       or business of the Company or any of its Subsidiaries.
 
    As used in this Section 4.19, the word "agreement" includes both oral and
written contracts, leases, understandings, arrangements and all other agreements
but does not include agreements providing insurance or reinsurance coverage,
agreements under which investments or cash are held in trust funds or escrow
accounts to provide collateral for holders of insurance policies or issuers of
letters of credit on behalf of the Company to such holders (as described in the
Company's Annual Report on Form 10-K for the year ended December 31, 1996),
agreements with accounting, financial and legal advisors made in connection with
the transactions contemplated by this Agreement or employee service agreements.
The term "Material Contracts" means the agreements of the Company or any of its
Subsidiaries required to be disclosed on Schedule 4.19 to this Agreement,
including agreements specifically identified in other Schedules hereto.
 
        (b) All of the Material Contracts are in full force and effect, are
    valid and binding and are enforceable in accordance with their terms in
    favor of the Company or such Subsidiary of the Company, as applicable,
    (assuming they have been duly authorized, executed and delivered by the
    other parties thereto), except as may be limited by applicable bankruptcy or
    insolvency laws. There are no material liabilities of any party to any
    Material Contract arising from any breach or default of any provision
    thereof and no event has occurred that, with the passage of time or the
    giving of notice or both, would constitute a breach or default by any party
    thereto.
 
        (c) The Company (or its Subsidiary, as applicable) has fulfilled all
    material obligations required pursuant to each Material Contract to have
    been performed by the Company or such Subsidiary prior to the date hereof,
    and the Company and its Subsidiaries have no reason to believe that the
    Company (or its Subsidiary, as applicable) will not be able to fulfill, when
    due, all of its obligations under the Material Contracts that remain to be
    performed after the date hereof.
 
    4.20  ABSENCE OF CERTAIN BUSINESS PRACTICES.  Neither the Company nor any of
its Subsidiaries, nor to the knowledge of the Company or any Subsidiary, any
employee or agent of the Company or any of its Subsidiaries or other Person
acting on the Company's or any Subsidiary's behalf, has directly or indirectly,
given or agreed to give any gift or similar benefit to any customer, supplier,
competitor or governmental employee or official (domestic or foreign) (i) that
could reasonably be expected to subject the Company or any of its Subsidiaries
to any damage or penalty in any civil, criminal or governmental litigation or
proceeding or (ii) that, if not given in the past, would have had a material
adverse effect on the Company or any of its Subsidiaries.
 
    4.21  BOOKS AND RECORDS.  The books of account, stock record books, minutes
books and other corporate records of the Company and each of its Subsidiaries
are in all material respects complete and correct and have been maintained in
accordance with good business practices.
 
    4.22  INFORMATION REGARDING ACQUISITIONS.  The Company has communicated to
Buyer information regarding (i) the acquisition by the Company (directly or
indirectly through an intermediate holding company jointly owned with another
strategic investor) of an interest in the holding company of Jago Managing
Agency Limited, or the reorganization of its interest in the holding company of
Jago Capital Limited to combine it with the interest acquired in the holding
company of Jago Managing Agency Limited and (ii) the acquisition by the Company
of a 49% shareholding in ATD Specialties Management Limited, as such
transactions are described on Schedule 6.01 to this Agreement. Such information
includes, without limitation, all material legal, business, financial and
accounting due diligence obtained by the Company with respect to the
acquisitions set forth in clause (i) and (ii) above (collectively, the
"Acquisition Information"), and, to the knowledge of the Company, the
Acquisition Information is complete and accurate in all material respects. The
Company has also provided to Buyer true and correct copies of the shareholders
agreement and coinsurance agreement with respect to the Polis Direct U.K.
Limited venture formed in 1996.
 
                                    APP-A-18
<PAGE>
                                   ARTICLE V
                    REPRESENTATIONS AND WARRANTIES OF BUYER
 
    Buyer represents and warrants to the Company as follows:
 
    5.01  ORGANIZATION AND QUALIFICATION.  Buyer is a corporation duly
incorporated, validly existing and in good standing under the laws of Delaware
and has full corporate power and authority to conduct its business as and to the
extent now conducted and to own, use and lease its assets and properties, except
for such failures to be so incorporated, existing and in good standing or to
have such power and authority which, individually or in the aggregate, are not
having and could not be reasonably expected to have a material adverse effect on
Buyer and its Subsidiaries taken as a whole. Buyer has previously delivered to
the Company correct and complete copies of its certificate of incorporation and
bylaws (or other comparable charter documents).
 
    5.02  CAPITAL STOCK.
 
        (a)  The authorized capital stock of Buyer consists solely of 30,000,000
    shares of Common Stock and 5,000,000 shares of preferred stock, par value
    $20.00 per share ("Preferred Stock"). As of the opening of trading on the
    NYSE on the date hereof, 11,641,977 shares of Common Stock were issued and
    outstanding, 120,700 shares were held in treasury and no shares were
    reserved for issuance except as set forth in Schedule 5.02 to this
    Agreement. Prior to the Closing, except as set forth in Schedule 5.02 to
    this Agreement, there will be no change in the number of issued and
    outstanding shares of Common Stock or shares of Common Stock held in
    treasury or reserved for issuance. As of the date hereof and as of the
    Closing, and except as set forth in Schedule 5.02 to this Agreement, no
    shares of Preferred Stock were, and will be, issued and outstanding, no
    shares were held in treasury and no shares were reserved for issuance. No
    bonds, debentures, notes or other instruments or evidence of indebtedness
    having the right to vote (or convertible into, or exercisable or
    exchangeable for, securities having the right to vote) on any matters on
    which Buyer's stockholders may vote ("Voting Debt") are issued or
    outstanding. All of the issued and outstanding shares of Common Stock and
    Preferred Stock are, and all shares reserved for issuance will be, upon
    issuance in accordance with the terms specified in the instruments or
    agreements pursuant to which they are issuable, duly authorized, validly
    issued, fully paid and nonassessable. Except pursuant to this Agreement and
    except as set forth in Schedule 5.02 to this Agreement, there are no
    outstanding Options obligating Buyer or any of its Subsidiaries to issue or
    sell any Voting Debt or shares of capital stock or other securities of Buyer
    or to grant, extend or enter into any Option with respect thereto.
 
        (b)  Except as disclosed in Schedule 5.02 to this Agreement, all of the
    outstanding beneficial interests of each Subsidiary of Buyer are owned,
    beneficially and of record, by Buyer or a Subsidiary wholly owned, directly
    or indirectly, by Buyer, free and clear of any Liens. Except as disclosed in
    Schedule 5.02 to this Agreement, there are no (i) outstanding Options
    obligating Buyer or any of its Subsidiaries to issue or sell any beneficial
    or other ownership interest of any Subsidiary of Buyer or to grant, extend
    or enter into any such Option or (ii) voting trusts, proxies or other
    commitments, understandings, restrictions or arrangements in favor of any
    Person other than Buyer or a Subsidiary wholly owned, directly or
    indirectly, by Buyer with respect to the voting of or the right to
    participate in dividends or other earnings on any beneficial or other
    ownership interest of any Subsidiary of Buyer.
 
        (c)  Except as disclosed in Schedule 5.02 to this Agreement or as
    contemplated by this Agreement, there are no outstanding contractual
    obligations of Buyer or any Subsidiary of Buyer to repurchase, redeem or
    otherwise acquire any shares of Common Stock or any beneficial or other
    ownership interest of any Subsidiary of Buyer or to provide funds to, or
    make any investment (in the form of a loan, capital contribution or
    otherwise) in, any Subsidiary of Buyer or any other Person which would have
    a material adverse effect on the Buyer and its Subsidiaries taken as a
    whole.
 
                                    APP-A-19
<PAGE>
        (d)  All shares of Common Stock to be issued to consummate the
    Transaction will, when issued, be duly authorized, validly issued, fully
    paid and nonassessable and will rank pari passu in all respects with the
    existing issued and outstanding shares of Common Stock, including the right
    to participate in Buyer's shareholder's rights plan adopted pursuant to that
    certain Rights Agreement dated as of June 14, 1997 and the right to receive
    in full all dividends or other distributions to be declared by reference to
    a record date on or after the Closing.
 
    5.03  AUTHORITY RELATIVE TO THIS AGREEMENT.  Buyer has full corporate power
and authority to enter into this Agreement, to perform its obligations hereunder
and to consummate the transactions contemplated hereby. The execution, delivery
and performance of this Agreement by Buyer and the consummation by Buyer of the
transactions contemplated hereby have been duly and validly approved by its
Board of Directors, and except for approval by the stockholders of Buyer, no
other corporate proceedings on the part of Buyer or its stockholders are
necessary to authorize the execution, delivery and performance of this Agreement
by Buyer and the consummation by Buyer of the transactions contemplated hereby.
This Agreement has been duly and validly executed and delivered by Buyer and
constitutes a legal, valid and binding obligation of Buyer enforceable against
Buyer in accordance with its terms, except as enforceability may be limited by
bankruptcy, insolvency, reorganization, moratorium or other similar laws
affecting the enforcement of creditors' rights generally and by general
equitable principles (regardless of whether such enforceability is considered in
a proceeding in equity or at law).
 
    5.04  NON-CONTRAVENTION; APPROVALS AND CONSENTS.
 
        (a)  The execution and delivery of this Agreement by Buyer does not, and
    the performance by Buyer of its obligations hereunder and the consummation
    of the transactions contemplated hereby will not, conflict with, result in a
    violation or breach of, constitute (with or without notice or lapse of time
    or both) a default under, result in or give to any Person any right of
    payment or reimbursement, termination, cancellation, modification or
    acceleration of, or result in the creation or imposition of any Lien upon
    any of the assets or properties of Buyer or any of its Subsidiaries under,
    any of the terms, conditions or provisions of (i) the certificates or
    articles of incorporation or bylaws (or other comparable charter documents)
    of Buyer or any of its Subsidiaries, or (ii) subject to the taking of the
    actions described in paragraph (b) of this Section, (x) any laws or orders
    of any Governmental or Regulatory Authority applicable to Buyer or any of
    its Subsidiaries or any of their respective assets or properties, or (y) any
    Contracts to which Buyer or any of its Subsidiaries is a party or by which
    Buyer or any of its Subsidiaries or any of their respective assets or
    properties is bound, excluding from the foregoing clauses (x) and (y)
    conflicts, violations, breaches, defaults, terminations, modifications,
    accelerations and creations and impositions of Liens which, individually or
    in the aggregate, could not be reasonably expected to have a material
    adverse effect on the ability of Buyer to consummate the transactions
    contemplated by this Agreement.
 
        (b)  Except (i) for the filing of a premerger notification report by
    Buyer under the HSR Act, (ii) for the filing of the Offer Documents with the
    SEC, (iii) for the filing with the SEC of a Registration Statement on Form
    S-4 with respect to the issuance of Common Stock contemplated by this
    Agreement (the "Registration Statement"), and such Registration Statement is
    declared effective by the SEC and remains effective at the Closing and (iv)
    as disclosed in Schedule 5.04 to this Agreement, no consent, approval or
    action of, filing with or notice to any Governmental or Regulatory Authority
    or other public or private third party is necessary or required under any of
    the terms, conditions or provisions of any law or order of any Governmental
    or Regulatory Authority or any Contract to which Buyer or any of its
    Subsidiaries is a party or by which Buyer or any of its Subsidiaries or any
    of their respective assets or properties is bound for the execution and
    delivery of this Agreement by Buyer, the performance by Buyer of its
    obligations hereunder or the consummation of the transactions contemplated
    hereby, other than such consents, approvals, actions, filings and notices
    which the failure to make or obtain, as the case may be, individually or in
    the aggregate, could
 
                                    APP-A-20
<PAGE>
    not be reasonably expected to have a material adverse effect on the ability
    of Buyer to consummate the transactions contemplated by this Agreement.
 
    5.05  SEC REPORTS AND FINANCIAL STATEMENTS.  Buyer has made available to the
Company prior to the execution of this Agreement a true and complete copy of
each form, report, schedule, registration statement, definitive proxy statement
and other document (together with all amendments thereof and supplements
thereto) filed by Buyer or any of its Subsidiaries with the SEC since January 1,
1995 (as such documents have since the time of their filing been amended or
supplemented, the "Buyer SEC Reports"), which are all the documents (other than
preliminary material) that Buyer and its Subsidiaries were required to file with
the SEC since such date. As of their respective dates, the Buyer SEC Reports (i)
complied as to form in all material respects with the requirements of the
Securities Act or the Exchange Act, as the case may be, and (ii) did not contain
any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary in order to make the statements
therein, in light of the circumstances under which they were made, not
misleading. The audited consolidated financial statements and unaudited interim
consolidated financial statements (including, in each case, the notes, if any,
thereto) included in the Buyer SEC Reports (the "Buyer Financial Statements")
complied as to form in all material respects with the published rules and
regulations of the SEC with respect thereto, were prepared in accordance with
United States generally accepted accounting principles applied on a consistent
basis during the periods involved (except as may be indicated therein or in the
notes thereto and except with respect to unaudited statements as permitted by
Form 10-Q or the SEC) and fairly and accurately present (subject, in the case of
the unaudited interim financial statements, to normal, recurring year-end audit
adjustments (which are not expected to be, individually or in the aggregate,
materially adverse to Buyer and its Subsidiaries taken as a whole)) the
consolidated financial position of Buyer and its consolidated subsidiaries at
the respective dates thereof and the consolidated results of their operations
and cash flows for the respective periods then ended. Except as set forth in
Schedule 5.05 to this Agreement, each Subsidiary of Buyer is treated as a
consolidated subsidiary of Buyer in the Buyer Financial Statements for all
periods covered thereby.
 
    5.06  ABSENCE OF CERTAIN CHANGES OR EVENTS.  Except as disclosed in the
Buyer SEC Reports filed prior to the date of this Agreement, (a) other than a
reasonably foreseeable change, event or development affecting Buyer resulting
from the execution of this Agreement or the transactions contemplated hereby,
since December 31, 1996 there has not been any change, event or development
having, or that could be reasonably expected to have, individually or in the
aggregate, a material adverse effect on Buyer and its Subsidiaries taken as a
whole or on the ability of Buyer to consummate the transactions contemplated by
this Agreement, and (b) except as disclosed in Schedule 5.06 to this Agreement,
since such date (i) Buyer and its Subsidiaries have conducted their respective
businesses only in the Ordinary Course of Business and (ii) neither Buyer nor
any of its Subsidiaries has taken any action which, if taken after the date
hereof, would constitute a breach of any provision of clause (ii) of Section
7.01(b).
 
    5.07  ABSENCE OF UNDISCLOSED LIABILITIES.  Except for matters reflected or
reserved against in the balance sheet for the period ended December 31, 1996
included in the Buyer Financial Statements or as disclosed in Schedule 5.07 to
this Agreement, neither Buyer nor any of its Subsidiaries had at such date, or
has incurred since that date, any liabilities or obligations (whether absolute,
accrued, contingent, fixed or otherwise, or whether due or to become due) of any
nature that would be required by United States generally accepted accounting
principles to be reflected on a consolidated balance sheet of Buyer and its
consolidated subsidiaries (including the notes thereto), except liabilities or
obligations (i) which were incurred in the Ordinary Course of Business and (ii)
which have not been, and could not be reasonably expected to be, individually or
in the aggregate, materially adverse to Buyer and its Subsidiaries taken as a
whole.
 
    5.08  LEGAL PROCEEDINGS.  There are no actions, suits, arbitrations or
proceedings pending or, to the knowledge of Buyer, threatened against, relating
to or affecting, nor to the knowledge of Buyer are there any Governmental or
Regulatory Authority investigations or audits pending or threatened against,
relating
 
                                    APP-A-21
<PAGE>
to or affecting, Buyer or any of its Subsidiaries or any of their respective
assets and properties which, individually or in the aggregate, could be
reasonably expected to have a material adverse effect on the ability of Buyer to
consummate the transactions contemplated by this Agreement and (ii) neither
Buyer nor any of its Subsidiaries is subject to any order of any Governmental or
Regulatory Authority which, individually or in the aggregate, could be
reasonably expected to have a material adverse effect on the ability of Buyer to
consummate the transactions contemplated by this Agreement.
 
    5.09  INFORMATION SUPPLIED.
 
        (a)  The Offer Documents, any proxy statement or information statement,
    as the case may be, relating to the Buyer Stockholders' Meeting, as amended
    and supplemented from time to time (as so amended and supplemented, the
    "Buyer Proxy Statement"), any registration statement, and any other
    documents to be filed by Buyer with the SEC or any other Governmental or
    Regulatory Authority in connection with the transactions contemplated hereby
    will not, on the date of its filing or, with respect to the Offer Documents
    and any registration statement, on the date they are filed with the SEC and,
    with respect to the Offer Documents first published, sent or given to
    stockholders of the Company, as the case may be, or, in the case of the
    Buyer Proxy Statement or any other document mailed to Buyer's stockholders
    by Buyer, at the date it is mailed to stockholders of Buyer and (with
    respect to the Buyer Proxy Statement) at the date of the Buyer Stockholders'
    Meeting, contain any untrue statement of a material fact or omit to state
    any material fact required to be stated therein or necessary in order to
    make the statements therein, in light of the circumstances under which they
    are made, not misleading, except that no representation is made by Buyer
    with respect to information supplied in writing by or on behalf of the
    Company expressly for inclusion therein and information incorporated by
    reference therein from documents filed by the Company or any of its
    Subsidiaries with the SEC. The Offer Documents, the Buyer Proxy Statement,
    any registration statement and any other such documents filed by Buyer with
    the SEC under the Exchange Act in connection with the transactions
    contemplated by this Agreement will comply as to form in all material
    respects with the requirements of the Exchange Act.
 
        (b)  Neither the information supplied or to be supplied in writing by or
    on behalf of Buyer for inclusion, nor the information incorporated by
    reference from documents filed by Buyer or any of its Subsidiaries with the
    SEC, in the Schedule 14D-9, the Buyer Proxy Statement or any other documents
    to be filed by Buyer or the Company with the SEC or any other Governmental
    or Regulatory Authority in connection with the other transactions
    contemplated by this Agreement will on the date of its filing or, with
    respect to the Schedule 14D-9, on the date it is filed with the SEC and
    first published, sent or given to stockholders of the Company, or, in the
    case of the Buyer Proxy Statement or any other document mailed to Buyer's
    stockholders by Buyer, at the date it is mailed to stockholders of Buyer and
    at the date of the Buyer Stockholders' Meeting, contain any untrue statement
    of a material fact or omit to state any material fact required to be stated
    therein or necessary in order to make the statements therein, in light of
    the circumstances under which they are made, not misleading.
 
    5.10  COMPLIANCE WITH LAWS AND ORDERS.  Buyer and its Subsidiaries hold all
permits, licenses, variances, exemptions, orders and approvals of all
Governmental and Regulatory Authorities necessary for the lawful conduct of
their respective businesses (the "Buyer Permits"), except for failures to hold
such permits, licenses, variances, exemptions, orders and approvals which,
individually or in the aggregate, are not having and could not be reasonably
expected to have a material adverse effect on Buyer and its Subsidiaries taken
as a whole. Buyer and its Subsidiaries are in compliance with the terms of the
Buyer Permits, except failures so to comply which, individually or in the
aggregate, are not having and could not be reasonably expected to have a
material adverse effect on Buyer and its Subsidiaries taken as a whole. Except
as disclosed in the Buyer SEC Reports filed prior to the date of this Agreement,
neither Buyer nor any of its Subsidiaries are in violation of or default under
any law or order of any Governmental or Regulatory Authority, except for such
violations or defaults which, individually or in the aggregate, are not
 
                                    APP-A-22
<PAGE>
having and could not be reasonably expected to have a material adverse effect on
Buyer and its Subsidiaries taken as a whole.
 
    5.11  COMPLIANCE WITH AGREEMENTS; CERTAIN AGREEMENTS.
 
        (a)  Except as disclosed in the Buyer SEC Reports filed prior to the
    date of this Agreement, neither Buyer nor any of its Subsidiaries nor, to
    the knowledge of Buyer, any other party thereto is in breach or violation
    of, or in default in the performance or observance of any term or provision
    of, and no event has occurred which, with notice or lapse of time or both,
    could be reasonably expected to result in a default under, (i) the
    certificate or articles of incorporation (or other comparable charter
    documents) of Buyer or any of its Subsidiaries or (ii) any Contract to which
    Buyer or any of its Subsidiaries is a party or by which Buyer or any of its
    Subsidiaries or any of their respective assets or properties is bound,
    except in the case of clause (ii) for breaches, violations and defaults
    which, individually or in the aggregate, are not having and could not be
    reasonably expected to have a material adverse effect on Buyer and its
    Subsidiaries taken as a whole.
 
        (b)  Except as disclosed in Schedule 5.11 to this Agreement or in the
    Buyer SEC Reports filed prior to the date of this Agreement or as provided
    for in this Agreement, as of the date hereof, neither Buyer nor any of its
    Subsidiaries is a party to any oral or written (i) agreement or plan,
    including any stock option, stock appreciation right, restricted stock or
    stock purchase plan, any of the benefits of which will be increased, or the
    vesting of the benefits of which will be accelerated, by the occurrence of
    any of the transactions contemplated by this Agreement or the value of any
    of the benefits of which will be calculated on the basis of any of the
    transactions contemplated by this Agreement or (ii) Contract which could
    have a material adverse effect on the ability of Buyer to consummate the
    transactions contemplated by this Agreement or could reasonably be expected
    to result in a material adverse effect on Buyer and its Subsidiaries after
    the consummation of the transactions contemplated by this Agreement.
 
    5.12  TAXES.
 
        (a)  Each of Buyer and its Subsidiaries has filed all material tax
    returns and reports required to be filed by it, or requests for extensions
    to file such returns or reports have been timely filed or granted and have
    not expired, and all such tax returns and reports are complete and accurate
    in all respects, except to the extent that such failures to file, have
    extensions granted that remain in effect or be complete and accurate in all
    respects, as applicable, individually or in the aggregate, would not have a
    material adverse effect on Buyer and its Subsidiaries taken as a whole.
    Buyer and each of its Subsidiaries has paid (or Buyer has paid on its
    behalf) all taxes shown as due for such tax returns and reports. The most
    recent financial statements contained in the Buyer SEC Reports filed prior
    to the date hereof reflect an adequate reserve for all taxes payable by
    Buyer and its Subsidiaries for all taxable periods and portions thereof
    accrued through the date of such financial statements, and no deficiencies
    for any taxes have been proposed, asserted or assessed against Buyer or any
    of its Subsidiaries that are not adequately reserved for, except for
    inadequately reserved taxes and inadequately reserved deficiencies that
    would not, individually or in the aggregate, have a material adverse effect
    on Buyer and its Subsidiaries taken as a whole. No requests for waivers of
    the time to assess any taxes against Buyer or any of its Subsidiaries have
    been granted or are pending, except for requests with respect to such taxes
    that have been adequately reserved for in the most recent Buyer Financial
    Statements contained in the Buyer SEC Reports filed prior to the date
    hereof, or, to the extent not adequately reserved, the assessment of which
    would not, individually or in the aggregate, have a material adverse effect
    on Buyer and its Subsidiaries taken as a whole. There are no material liens
    for taxes (other than for current taxes not yet due and payable) on the
    assets of Buyer or its Subsidiaries. Buyer has made available to the Company
    true and complete copies of its federal income tax returns for the fiscal
    year ended December 31, 1995. Except as set forth in Schedule 5.12 to this
    Agreement, neither Buyer nor any of its Subsidiaries is a party to or bound
    by any agreement providing for the allocation or sharing of taxes with any
    entity which is not, either directly or indirectly, a wholly owned
 
                                    APP-A-23
<PAGE>
    Subsidiary of Buyer. Neither Buyer nor any of its Subsidiaries has filed a
    consent pursuant to or agreed to the application of Section 341(f) of the
    Code. Buyer is not a "United States real property holding corporation" as
    defined in Section 897(c)(2) of the Code during the applicable period
    specified in Section 897(c)(1)(A)(ii) of the Code.
 
        (b)  As used in this Section 5.12, "taxes" shall include all federal,
    state, local and foreign income, franchise, property, sales, use, excise and
    other taxes, including obligations for withholding taxes from payments due
    or made to any other Person and any interest, penalties or additions to tax.
 
        (c)  REORGANIZATION REPRESENTATIONS AND WARRANTIES OF BUYER.
 
            (i) Except as set forth on Schedule 5.02 to this Agreement, Buyer
       has no plan or intention to liquidate the Company, to merge the Company
       into another corporation, to cause the Company to sell or otherwise
       dispose of any of its assets, except for dispositions made in the
       Ordinary Course of Business, or to sell or otherwise dispose of any of
       the Company Common Stock acquired pursuant to the Offer.
 
            (ii) Buyer publicly announced on March 3, 1997 that its Board of
       Directors authorized the repurchase of up to $15,000,000 of its Common
       Stock through open market purchases (the "Buy Back"). Pursuant to the Buy
       Back, (a) the Common Stock repurchases will be made for a valid business
       purpose unrelated to the Transaction, (b) the Common Stock to be
       repurchased will be widely held, and (c) the Common Stock repurchases
       will be made in the open market. Although Buyer is authorized to
       repurchase some of its Common Stock from time to time pursuant to the Buy
       Back, Buyer has no plan or intention to reacquire any of its Common Stock
       issued in the exchange.
 
           (iii) Buyer will acquire Company Common Stock solely in exchange for
       Common Stock. For purposes of this representation, Company Common Stock
       redeemed for cash or other property furnished by Buyer will be considered
       as acquired by Buyer. Further, no liabilities of the Company or the
       stockholders of the Company will be assumed by Buyer, nor will any of the
       Company Common Stock be subject to any liabilities.
 
            (iv) Buyer does not own, directly or indirectly, nor has it owned
       during the past five years, directly or indirectly, any stock of the
       Company.
 
            (v) Buyer is not an investment company as defined in Section
       368(a)(2)(F)(iii) and (iv) of the Code.
 
            (vi) None of the compensation received (or to be received) by any
       stockholder-employee of the Company will be separate consideration for,
       or allocable to, any of his shares of Company Common Stock. None of the
       Common Stock received by any stockholder-employees of the Company in
       connection with this Agreement will be separate consideration for, or
       allocable to, any employment agreement or arrangement. The compensation
       paid to any stockholder-employee of the Company will be commensurate with
       amounts that would be paid to a third party bargaining at arm's length of
       similar services.
 
           (vii) The payment of cash in respect of fractional shares of Common
       Stock is solely for the purpose of avoiding the expense and inconvenience
       to Buyer of issuing fractional shares and does not represent separately
       bargained-for consideration. The total cash consideration that will be
       paid in the Transaction to the former Company stockholders instead of
       issuing fractional shares of Common Stock will not exceed one percent of
       the total consideration that will be issued in the Transaction to the
       Company stockholders in exchange for their shares of the Company Common
       Stock. The fractional share interest of each former Company stockholder
       will be aggregated and no former Company stockholder will receive cash in
       an amount equal to or greater than the value of one full share of Common
       Stock.
 
                                    APP-A-24
<PAGE>
          (viii) Buyer has no plan or intention to allow the Company, following
       the Closing, to issue additional shares of its stock that would result in
       Buyer losing control of the Company within the meaning of Section 368(c)
       of the Code.
 
    5.13  EMPLOYEE BENEFIT PLANS; ERISA.
 
        (a)  Except as described in the Buyer SEC Reports filed prior to the
    date of this Agreement or as would not have a material adverse effect on
    Buyer and its Subsidiaries taken as a whole, (i) all Buyer Employee Benefit
    Plans are in compliance with all applicable requirements of law, including
    the Employee Retirement Income Security Act of 1974, as amended, and the
    rules and regulations thereunder ("ERISA") and the Code, and (ii) neither
    Buyer nor any of its Subsidiaries has any liabilities or obligations with
    respect to any such Buyer Employee Benefit Plans, whether accrued,
    contingent or otherwise, nor to the knowledge of Buyer are any such
    liabilities or obligations expected to be incurred. Except as described in
    Schedule 5.13 to this Agreement, the execution of, and performance of the
    transactions contemplated in, this Agreement will not (either alone or upon
    the occurrence of any additional or subsequent events) constitute an event
    under any Buyer Employee Benefit Plan that will or may result in any payment
    (whether of severance pay or otherwise), acceleration, forgiveness of
    indebtedness, vesting, distribution, increase in benefits or obligation to
    fund benefits with respect to any employee. The only severance agreements or
    severance policies applicable to Buyer or any of its Subsidiaries are the
    agreements and policies specifically referred to in Schedule 5.13 to this
    Agreement.
 
        (b)  As used herein:
 
            (i) "Buyer Employee Benefit Plan" means any Plan entered into,
       established, maintained, sponsored, contributed to or required to be
       contributed to by Buyer or any of its Subsidiaries for the benefit of the
       current or former employees or directors of Buyer or any of its
       Subsidiaries and existing on the date of this Agreement or at any time
       subsequent thereto and on or prior to the Closing and, in the case of a
       Plan which is subject to Part 3 of Title I of ERISA, Section 412 of the
       Code or Title IV of ERISA, at any time since January 1, 1990.
 
            (ii) "Plan" means any employment, bonus, incentive compensation,
       deferred compensation, pension, profit sharing, retirement, stock
       purchase, stock option, stock ownership, stock appreciation rights,
       phantom stock, leave of absence, layoff, vacation, day or dependent care,
       legal services, cafeteria, life, health, medical, accident, disability,
       workmen's compensation or other insurance, severance, separation,
       termination, change of control or other benefit plan, agreement,
       practice, policy, program or arrangement of any kind, whether written or
       oral, including, but not limited to any "employee benefit plan" within
       the meaning of Section 3(3) of ERISA.
 
    5.14  LABOR MATTERS.  Except as disclosed in Buyer SEC Reports filed prior
to the date of this Agreement or in Schedule 5.14 to this Agreement, there are
no controversies pending or, to the knowledge of Buyer, threatened between Buyer
or any of its Subsidiaries and any representatives of its employees, except as
would not, individually or in the aggregate, have a material adverse effect on
Buyer and its Subsidiaries taken as a whole, and, to the knowledge of Buyer,
there are no material organizational efforts presently being made involving any
of the employees of Buyer or any of its Subsidiaries. Since December 31, 1996,
there has been no work stoppage, strike or other concerted action by employees
of Buyer or any of its Subsidiaries except as have not, individually or in the
aggregate, had a material adverse effect on Buyer and its Subsidiaries taken as
a whole.
 
    5.15  VOTE REQUIRED.  The affirmative vote of the holders of record of at
least a majority of the shares of Common Stock voting at a duly constituted
meeting of Buyer's stockholders with respect to the adoption of this Agreement,
if required by applicable law, is the only vote of the holders of any class or
series of the capital stock of Buyer required to adopt this Agreement and the
transactions contemplated hereby.
 
    5.16  OWNERSHIP OF COMPANY COMMON STOCK.  Except as disclosed in Schedule
5.16 to this Agreement, neither Buyer nor any of its Subsidiaries or other
affiliates beneficially owns any shares of Company Common Stock.
 
                                    APP-A-25
<PAGE>
                                   ARTICLE VI
                            COVENANTS OF THE COMPANY
 
    6.01.  COVENANTS OF THE COMPANY.  At all times from and after the date
hereof until the Closing, the Company covenants and agrees as to itself and its
Subsidiaries that (except as expressly permitted by this Agreement, or to the
extent that Buyer shall otherwise previously consent in writing):
 
        (a)  ORDINARY COURSE.  Subject to the limitations set forth in Section
    6.01(b), the Company and its Subsidiaries shall conduct their respective
    businesses only in, and neither the Company nor any such Subsidiary shall
    take any action except in, the Ordinary Course of Business.
 
        (b)  SPECIFIC ACTIONS.  Without limiting the generality of paragraph (a)
    of this Section 6.01, (i) the Company and its Subsidiaries shall use all
    commercially reasonable efforts to preserve intact in all material respects
    their present business organizations and reputation, to keep available the
    services of their key officers and employees, to maintain their assets and
    properties in good working order and condition, ordinary wear and tear
    excepted, to maintain insurance on their tangible assets and businesses in
    such amounts and against such risks and losses as are currently in effect,
    to preserve their relationships with significant customers and suppliers and
    others having significant business dealings with them and to comply in all
    material respects with all contracts and laws and orders of all Governmental
    or Regulatory Authorities applicable to them, and (ii) the Company shall
    not, nor shall it permit any of its Subsidiaries to, except as otherwise
    expressly provided for in this Agreement or in Schedule 6.01 to this
    Agreement:
 
               (A) amend or propose to amend its memorandum and articles of
           association (or other comparable corporate charter documents);
 
               (B) (w) declare, set aside or pay any dividends on, or make other
           distributions in respect of, any of its capital stock, except for the
           declaration and payment of dividends by the Company at rates and
           times and otherwise consistent with past practice or by a wholly
           owned Subsidiary of the Company solely to the Company or another
           wholly owned Subsidiary of the Company, (x) split, combine,
           reclassify or take similar action with respect to any of its capital
           stock or issue or authorize or propose the issuance of any other
           securities in respect of, in lieu of or in substitution for shares of
           its capital stock, (y) adopt a plan of complete or partial
           liquidation or resolutions providing for or authorizing such
           liquidation or a dissolution, merger, consolidation, restructuring,
           recapitalization or other reorganization or (z) directly or
           indirectly redeem, repurchase or otherwise acquire any shares of its
           capital stock or any Option with respect thereto;
 
               (C) issue, deliver or sell, or authorize or propose the issuance,
           delivery or sale of, any shares of its capital stock or other
           securities or Company Voting Debt or any Option with respect thereto
           (other than (x) the issuance of Company Common Stock upon the
           exercise of Company Stock Options and outstanding on the date of this
           Agreement and in accordance with their present terms or (y) the
           issuance by a wholly owned Subsidiary of its capital stock to its
           parent corporation);
 
               (D) directly or indirectly acquire, or agree to acquire, (by
           merging or consolidating with, or by purchasing a substantial equity
           interest in or a substantial portion of the assets of, or by any
           other manner) any business or any corporation, partnership,
           association or other business organization or division thereof or
           otherwise acquire or agree to acquire any assets in an amount which
           exceeds, individually or in the aggregate, $250,000 other than in the
           Ordinary Course of Business;
 
               (E) other than in the Ordinary Course of Business, and other than
           sales by the Company or any of its Subsidiaries to the Company or any
           of its Subsidiaries, sell, lease,
 
                                    APP-A-26
<PAGE>
           grant any Security Interest in or otherwise dispose of or encumber
           any of its assets or properties, including the capital stock of its
           Subsidiaries;
 
               (F) except to the extent required by applicable law, (x) permit
           any material change in (1) any marketing, purchasing, investment,
           accounting, financial reporting, inventory, credit, allowance or tax
           practice, policy or procedure or (2) any method of calculating any
           bad debt, contingency or other reserve for accounting, financial
           reporting or tax purposes or (y) make any material tax election or
           settle or compromise any material income tax liability with any
           Governmental or Regulatory Authority;
 
               (G) except for borrowings under existing credit facilities of up
           to $10,000,000 in the aggregate in connection with the acquisition by
           the Company of an interest in the holding company of Jago Managing
           Agency Limited and the purchase of additional capacity for Jago
           Capital Limited (as disclosed in Schedule 6.01 to this Agreement),
           (x) assume or incur any indebtedness for borrowed money or guarantee
           any such indebtedness or issue or sell any debt securities or
           warrants or rights to acquire any debt securities or guarantee any
           debt securities of others or enter into any lease (whether such lease
           is an operating or capital lease) other than in the Ordinary Course
           of Business, (y) voluntarily purchase, cancel, prepay or otherwise
           provide for a complete or partial discharge in advance of a scheduled
           repayment date with respect to, or waive any right under, any
           indebtedness for borrowed money other than in the Ordinary Course of
           Business, or (z) enter into any "keep well" or other agreement or
           arrangement to maintain the financial condition of another Person;
 
               (H) except as disclosed in Schedule 4.04(a), enter into, adopt,
           amend in any material respect (except as may be required by
           applicable law) or terminate the Disclosed Scheme, or other
           agreement, arrangement, plan or policy between the Company or one of
           its Subsidiaries and one or more of its directors, officers or
           employees, or, except for normal increases in the Ordinary Course of
           Business that, in the aggregate, do not result in a material increase
           in benefits or compensation expense to either the Company or any of
           its Subsidiaries, increase in any manner the compensation or fringe
           benefits of any director, officer or employee or pay any benefit not
           required by any plan or arrangement in effect as of December 31,
           1996;
 
               (I) except as to insurance and reinsurance Contracts and as to
           Contracts or transactions entered or to be entered into in the
           Ordinary Course of Business which do not obligate the Company or any
           of its Subsidiaries (either in a single Contract or transaction or a
           series of related Contracts or transactions) to pay in excess of
           $500,000: (x) enter into any Contract; or (y) amend, waive, modify or
           terminate any existing Contract, or (z) engage in any new transaction
           outside the Ordinary Course of Business or not on an arm's length
           basis, with any third party, including but not limited to, any
           affiliate of the Company or any of its Subsidiaries;
 
               (J) make any capital expenditures or commitments in excess of
           100,000 for additions to plant, property or equipment constituting
           capital assets except in the Ordinary Course of Business; or
 
               (K) enter into any Contract, commitment or arrangement to do or
           engage in any of the foregoing, except as otherwise permitted in this
           Section 6.01(b).
 
Nothing in this Section 6.01 shall prevent the Company from continuing to
negotiate with respect to or consummating the acquisition by the Company
(directly or indirectly through an intermediate holding company jointly owned
with another strategic investor) of an interest in the holding company of Jago
Managing Agency Limited, or from reorganizing its interest in the holding
company of Jago Capital Limited to combine it in with the interest acquired in
the holding company of Jago Managing Agency Limited or the acquisition by the
Company of a 49% shareholding in ATD Specialties Management
 
                                    APP-A-27
<PAGE>
Limited, as such transactions are described on Schedule 6.01 to this Agreement;
provided, however, that the Company shall keep Buyer informed of the status of
and all material information with respect to such transactions and shall, from
the date hereof until Closing, obtain the consent of Buyer prior to taking any
action which would materially change the terms of such transactions.
 
        (c)  ADVICE.  The Company shall confer on a regular and frequent basis
    with Buyer with respect to its business and operations and other matters
    relevant to the transactions contemplated by this Agreement, and shall
    promptly advise Buyer, orally and in writing, of any change or event,
    including, without limitation, any complaint, investigation, hearing by or
    notice or communication from any Governmental or Regulatory Authority or the
    institution or threat of litigation, having, or which, insofar as can be
    reasonably foreseen, could have, a material adverse effect on the Company
    and its Subsidiaries taken as a whole or on the ability of the Company to
    consummate the transactions contemplated by this Agreement or of any notice
    or other communication from any Person alleging that the consent of such
    Person is or may be required in connection with the transactions
    contemplated by this Agreement; provided that the Company shall not be
    required to make any disclosure to the extent such disclosure would
    constitute a violation of any applicable law.
 
    6.02  NO SOLICITATIONS.  Prior to the Closing, the Company agrees (a) that
neither it nor any of its Subsidiaries shall, nor shall it or any of its
Subsidiaries permit their respective Representatives to, initiate, solicit or
encourage, directly or indirectly, any inquiries or the making or implementation
of any proposal or offer (including, without limitation, any proposal or offer
to its stockholders) with respect to a merger, consolidation or other business
combination including the Company or any of its Subsidiaries or any acquisition
or similar transaction (including, without limitation, a tender or exchange
offer) involving an Alternative Proposal, or engage in any negotiations
concerning, or provide any confidential information or data to, or have any
discussions with, or enter into any agreement or understanding with, any Person
or group relating to, an Alternative Proposal (excluding the transactions
contemplated by this Agreement), or otherwise facilitate any effort or attempt
to make or implement an Alternative Proposal; and (b) that it will notify Buyer
immediately if any such inquiries, proposals or offers are received by, any such
information is requested from, or any such negotiations or discussions are
sought to be initiated or continued with, it or any of such Persons or groups
and will identify the party making such inquiry, proposal, offer or request,
except to the extent such notification would, in the written opinion of the
Company's outside counsel (a copy of which shall be delivered to Buyer), cause
the Company or its Board of Directors to be in violation of any applicable law,
regulation or governmental order; provided, however, that prior to acquisition
of shares of Company Common Stock pursuant to the Offer, nothing contained in
this Section 6.02 shall prohibit the Board of Directors of the Company from, to
the extent applicable, complying with Rule 14e-2 promulgated under the Exchange
Act, or the UK City Code on Takeovers and Mergers (the "City Code"), with regard
to an Alternative Proposal. "Alternative Proposal" shall mean any of the
following (other than the transactions between the Company and Buyer
contemplated hereunder) involving the Company or any of its Subsidiaries: (i)
any merger, consolidation, share exchange, recapitalization, business
combination, or other similar transaction; (ii) any sale, lease, exchange,
mortgage, pledge, transfer or other disposition of 10% or more of the assets of
the Company and its Subsidiaries, taken as a whole, in a single transaction or
series of transactions; (iii) any tender offer or exchange offer for or other
purchase of 10% or more of the outstanding shares of capital stock of the
Company or the filing of a registration statement under the Securities Act in
connection therewith; or (iv) any public announcement of a proposal, plan or
intention to do any of the foregoing. Nothing in this Section 6.02 shall permit
the Company to terminate this Agreement except as specifically permitted by
Article X of this Agreement.
 
    6.03  TAX COVENANTS OF THE COMPANY.  Subject to the provisions of Section
10.02, the Company will pay its own expenses incurred in connection with the
transactions contemplated by this Agreement.
 
    6.04  APPROVAL OF COMPANY STOCKHOLDERS.  The Company shall, through its
Board of Directors, duly call, give notice of, convene and hold an extraordinary
general meeting of the Company (the "Company Stockholders' Meeting"), for the
purposes of adopting a special resolution to amend, subject to and
 
                                    APP-A-28
<PAGE>
conditioned upon the Closing, the Company's Articles of Association by the
deletion of the existing Articles 75, 76 and 87 (and of references thereto), and
by the deletion of the definition of "Designated Shareholders" in Article 2 (the
"Company Amendment").
 
                                  ARTICLE VII
                               COVENANTS OF BUYER
 
    7.01  COVENANTS OF BUYER.  At all times from and after the date hereof until
the Closing, Buyer covenants and agrees as to itself and its Subsidiaries that
(except as expressly permitted by this Agreement, or to the extent that the
Company shall otherwise previously consent in writing):
 
        (a)  ORDINARY COURSE.  Subject to the limitations set forth in Section
    7.01(b), Buyer and its Subsidiaries shall conduct their respective
    businesses only in, and neither Buyer nor any such Subsidiary shall take any
    action except in, the Ordinary Course of Business.
 
        (b)  SPECIFIC ACTIONS.  Without limiting the generality of paragraph (a)
    of this Section 7.01, (i) Buyer and its Subsidiaries shall use all
    commercially reasonable efforts to preserve intact in all material respects
    their present business organizations and reputation, to keep available the
    services of their key officers and employees, to maintain their assets and
    properties in good working order and condition, ordinary wear and tear
    excepted, to maintain insurance on their tangible assets and businesses in
    such amounts and against such risks and losses as are currently in effect,
    to preserve their relationships with significant customers and suppliers and
    others having significant business dealings with them and to comply in all
    material respects with all contracts and laws and orders of all Governmental
    or Regulatory Authorities applicable to them, and (ii) Buyer shall not,
    except as otherwise expressly provided for in this Agreement or in Schedule
    7.01 to this Agreement:
 
               (A) except as set forth on Schedule 5.02 to this Agreement, (w)
           declare, set aside or pay any dividends on or make other
           distributions in respect of any of its capital stock, except for the
           declaration and payment of dividends by Buyer at rates and times and
           otherwise consistent with past practice or by a wholly owned
           Subsidiary of Buyer solely to Buyer or another wholly owned
           Subsidiary of Buyer, (x) split, combine, reclassify or take similar
           action with respect to any of its capital stock or issue or authorize
           or propose the issuance of any other securities in respect of, in
           lieu of or in substitution for shares of its capital stock, (y) adopt
           a plan of complete or partial liquidation or resolutions providing
           for or authorizing such liquidation or a dissolution, merger,
           consolidation, sale of all or substantially all of its assets,
           restructuring, recapitalization or other reorganization or (z)
           directly or indirectly redeem, repurchase or otherwise acquire any
           shares of its capital stock or any Option with respect thereto;
 
               (B) enter into any Contract, commitment or arrangement to do or
           engage in any of the foregoing, except as otherwise permitted in this
           Section 7.01(b).
 
        (c)  ADVICE.  Buyer shall confer on a regular and frequent basis with
    the Company with respect to substantial matters involving its business and
    operations and with respect to all matters relevant to the transactions
    contemplated by this Agreement, and shall promptly advise the Company,
    orally and in writing, of any change or event, including, without
    limitation, any complaint, investigation, hearing by or notice or
    communication from any Governmental or Regulatory Authority or the
    institution or threat of litigation, having, or which, insofar as can be
    reasonably foreseen, could have, a material adverse effect on Buyer and its
    Subsidiaries taken as a whole or on the ability of Buyer to consummate the
    transactions contemplated by this Agreement or of any notice or other
    communication from any Person alleging that the consent of such Person is or
    may be required in connection with the transactions contemplated by this
    Agreement; provided that Buyer shall not be required to make any disclosure
    to the extent such disclosure would constitute a violation of any applicable
    law.
 
                                    APP-A-29
<PAGE>
    7.02  TAX COVENANTS OF BUYER.
 
        (a)  Subject to the provisions of Section 10.02, Buyer will pay its own
    expenses incurred in connection with the transactions contemplated by this
    Agreement.
 
        (b)  Following the Closing, Buyer will cause the Company to continue its
    historic business or use a significant portion of its historic business
    assets in a business.
 
        (c)  Buyer shall use its best efforts to take all steps to ensure that
    the Transaction qualifies as a reorganization within the meaning of Section
    368(a)(1)(B) of the Code and shall not take (or, to the extent it is able,
    permit any other Person to take) any steps that prevent such qualification.
 
                                  ARTICLE VIII
                             ADDITIONAL AGREEMENTS
 
    8.01  ACCESS TO INFORMATION; CONFIDENTIALITY.  (a) The Company shall, and
shall cause each of its Subsidiaries to, throughout the period from the date
hereof to the Closing, (i) provide Buyer and its Representatives with full
access, upon reasonable prior notice and during normal business hours, to all
officers, employees, agents, attorneys and accountants of the Company and its
Subsidiaries and their respective assets, properties, books and records, but
only to the extent that such access does not unreasonably interfere with the
business and operations of the Company and its Subsidiaries, and (ii) furnish
promptly to such Persons (x) a copy of each report, statement, schedule and
other document filed or received by the Company or any of its Subsidiaries
pursuant to the requirements of federal or state securities laws and each
material report, statement, schedule and other document filed with any other
Governmental or Regulatory Authority, and (y) all other information and data
(including, without limitation, copies of Contracts, the Disclosed Scheme or
other similar arrangement and other books and records) concerning the business
and operations of the Company and its Subsidiaries as Buyer, or any of such
other Persons reasonably may request.
 
        (b)  Buyer shall, throughout the period from the date hereof to the
    Closing, provide the Company and its Representatives with full access, upon
    reasonable prior notice and during normal business hours, to the executive
    officers of Buyer, but only to the extent that such access does not
    unreasonably interfere with the business and operations of the Buyer and its
    Subsidiaries.
 
    8.02  PREPARATION OF PROXY STATEMENT AND REGISTRATION STATEMENT BY
BUYER.  Buyer shall prepare and file with the SEC the Registration Statement
containing the Buyer Proxy Statement and the prospectus contained in the
Registration Statement of Buyer and the offer documents required pursuant to the
City Code and the Exchange Act as soon as reasonably practicable after the date
hereof, and shall use their respective best efforts to have the Buyer Proxy
Statement cleared and the Registration Statement declared effective by the SEC.
If at any time prior to the Closing any event shall occur that should be set
forth in an amendment of or a supplement to the Buyer Proxy Statement or the
Registration Statement, Buyer shall prepare and file with the SEC such amendment
or supplement as soon thereafter as is reasonably practicable. Buyer and the
Company shall cooperate with each other in the preparation of the Buyer Proxy
Statement and the Registration Statement, and Buyer shall notify the Company of
the receipt of any comments of the SEC with respect to the Buyer Proxy Statement
or the Registration Statement and of any requests by the SEC for any amendment
or supplement thereto or for additional information, and shall provide to the
Company promptly copies of all correspondence between Buyer or any
representative of Buyer and the SEC with respect to the Buyer Proxy Statement or
the Registration Statement. Buyer shall give the Company and its counsel the
opportunity to review the Buyer Proxy Statement and the Registration Statement
and all responses to requests for additional information by and replies to
comments of the SEC before their being filed with, or sent to, the SEC. Each of
the Company and Buyer agrees to use its best efforts, after consultation with
the other party, to respond promptly to all such
 
                                    APP-A-30
<PAGE>
comments of and requests by the SEC and to cause the Buyer Proxy Statement to be
mailed to the holders of Common Stock entitled to vote at the Buyer
Stockholders' Meeting at the earliest practicable time.
 
    8.03  APPROVAL OF STOCKHOLDERS.  Buyer shall, through its Board of
Directors, duly call, give notice of, convene and hold a meeting of its
stockholders (the "Buyer Stockholders' Meeting") for the purpose of approving
the issuance of Common Stock contemplated by this Agreement (the "Stockholders'
Approval") as soon as reasonably practicable after the date hereof.
 
    8.04  REGULATORY AND OTHER APPROVALS.  Subject to the terms and conditions
of this Agreement and without limiting the provisions of Sections 8.02 and 8.03,
each of the Company and Buyer will proceed diligently and in good faith to, as
promptly as practicable, (a) obtain all consents, approvals or actions of, make
all filings with and give all notices to Governmental or Regulatory Authorities
or any other public or private third parties required by this Agreement of
Buyer, the Company or any of their respective Subsidiaries to consummate the
transactions and the other matters contemplated hereby, and (b) provide such
other information and communications to such Governmental or Regulatory
Authorities or other public or private third parties as the other party or such
Governmental or Regulatory Authorities or other public or private third parties
may reasonably request in connection therewith. In addition to and not in
limitation of the foregoing, each of the parties will (x) take promptly all
actions necessary to make the filings required of Buyer and the Company or their
affiliates under the HSR Act, (y) comply at the earliest practicable date with
any request for additional information received by such party or its affiliates
from the Federal Trade Commission (the "FTC") or the Antitrust Division of the
Department of Justice (the "Antitrust Division") pursuant to the HSR Act, and
(z) cooperate with the other party in connection with such party's filings under
the HSR Act and in connection with resolving any investigation or other inquiry
concerning the Offer or the other matters contemplated by this Agreement
commenced by either the FTC or the Antitrust Division or state attorneys
general.
 
    8.05  EMPLOYMENT AND SEVERANCE AGREEMENT.  From and after the Closing, the
Company will honor without modification and in accordance with their respective
terms each of the employment and severance agreements of the Company and its
Subsidiaries listed in Schedule 4.11 to this Agreement, as such agreements are
in effect on the date hereof except for, and giving effect to, any and all
amendments, modifications, restatements and other changes to the terms of any
such employment and severance agreements which are agreed to by the Company,
Buyer and the other party or parties to such agreements on or after the date
hereof.
 
    8.06  DIRECTORS' AND OFFICERS' INDEMNIFICATION AND INSURANCE.
 
        (a)  Except to the extent required by law, Buyer will not take any
    action so as to amend, modify or repeal the provisions for indemnification
    of any directors or officers of the Company or any of its Subsidiaries (the
    "Indemnified Parties") contained in the memorandum and articles of
    association (or other comparable charter documents) of the Company and its
    Subsidiaries (which as of the Closing shall be no more favorable to such
    individuals than those maintained by the Company and its Subsidiaries on the
    date hereof) in such a manner as would adversely affect the rights of any
    individual who shall have served as a director or officer of the Company or
    any of its Subsidiaries prior to the Closing to be indemnified by such
    corporations in respect of their serving in such capacities prior to the
    Closing.
 
        (b)  Buyer and the Company shall, until the fourth anniversary of the
    Closing Date and for so long thereafter as any claim asserted prior to such
    date has not been fully adjudicated by a court of competent jurisdiction,
    cause to be maintained in effect, to the extent available, the policies of
    directors' and officers' liability insurance maintained by the Company and
    its Subsidiaries as of the date hereof (or policies of at least the same
    coverage and amounts containing terms that are no less advantageous to the
    insured parties) with respect to claims arising from facts or events that
    occurred on or prior to the Closing; provided, however, that Buyer shall not
    be required in order to maintain or procure such coverage to pay an annual
    premium in excess of one and one-half times the current
 
                                    APP-A-31
<PAGE>
    annual premium paid by the Company and each of its Subsidiaries for its
    existing coverage (the "Cap") (which aggregate current annual premium the
    Company represents and warrants to be approximately $251,000); and provided,
    further, that if equivalent coverage cannot be obtained, or can be obtained
    only by paying an annual premium in excess of the Cap, Buyer shall only be
    required to obtain as much coverage as can be obtained by paying an annual
    premium equal to the Cap. Nothing in this Section 8.06(b) shall prevent
    Buyer, following the Closing, from replacing the policies contemplated by
    this Section 8.06(b) with the policies of directors' and officers' liability
    insurance maintained by Buyer for the benefit of the officers and directors
    of Buyer; provided that such coverage must otherwise satisfy this Section
    8.06(b).
 
        (c)  The provisions of this Section 8.06 are intended to be for the
    benefit of, and shall be enforceable by, each Indemnified Party and each
    party entitled to insurance coverage under paragraph (b) above,
    respectively, and his or her heirs and legal representatives, and shall be
    in addition to any other rights an Indemnified Party may have under the
    memorandum and articles of association (or other comparable charter
    documents) of the Company or any of its Subsidiaries, under the law of
    England and Wales or otherwise, but in relation to the obligations of the
    Company shall be subject to, and shall not be more extensive than permitted
    under, the law of England and Wales.
 
    8.07  FEES AND EXPENSES.  Subject to the provisions of Section 10.02,
whether or not the transactions contemplated by this Agreement are consummated,
all costs and expenses incurred in connection with this Agreement and the
transactions contemplated hereby shall be paid by the party incurring such cost
or expense.
 
    8.08  BROKERS OR FINDERS.  Each of Buyer and the Company represents, as to
itself and its affiliates, that no agent, broker, investment banker, financial
advisor or other firm or Person is or will be entitled to any broker's or
finder's fee or any other commission or similar fee in connection with any of
the transactions contemplated by this Agreement except Donaldson, Lufkin &
Jenrette Securities Corporation, whose fees and expenses will be paid by the
Company in accordance with the Company's agreement with such firm (a true and
complete copy of which has been delivered by the Company to Buyer prior to the
execution of this Agreement), and Smith Barney Inc., whose fees and expenses
will be paid by Buyer in accordance with Buyer's agreement with such firm (a
true and complete copy of which has been delivered by Buyer to the Company prior
to the execution of this Agreement), and each of Buyer and the Company shall
indemnify and hold the other harmless from and against any and all claims,
liabilities or obligations with respect to any other such fee or commission or
expenses related thereto asserted by any Person on the basis of any act or
statement alleged to have been made by such party or its affiliate.
 
    8.09  TAKEOVER STATUTES.  If any "fair price", "moratorium", "control share
acquisition" or other form of antitakeover statute or regulation shall become
applicable to the transactions contemplated by this Agreement, Buyer and the
Company and the members of the Board of Directors of each of Buyer and the
Company shall grant such approvals and take such actions as are reasonably
necessary so that the transactions contemplated by this Agreement may be
consummated as promptly as practicable on the terms contemplated hereby and
otherwise act to eliminate or minimize the effects of such statute or regulation
on the transactions contemplated by this Agreement. Nothing in this Section 8.09
shall require (i) Buyer to take any action which would materially and adversely
affect the business of the Buyer and its Subsidiaries, taken as a whole, or (ii)
the Company to take any action which would materially and adversely affect the
business of the Company and its Subsidiaries, taken as a whole.
 
    8.10  CONVEYANCE TAXES.  The Company and Buyer shall cooperate in the
preparation, execution and filing of all returns, questionnaires, applications
or other documents regarding any real property transfer or gains, sales, use,
transfer, value added, stock transfer and stamp taxes, any transfer, recording,
registration and other fees, and any similar taxes which become payable, if any,
in connection with the transactions contemplated by this Agreement that are
required or permitted to be filed on or before the Closing.
 
                                    APP-A-32
<PAGE>
    8.11  NOTICE.  Each of Buyer and the Company will notify the other of any
event, transaction or circumstance, as soon as practical after it becomes known
to such party, that causes or will cause any covenant or agreement of Buyer or
the Company under this Agreement to be breached or any of the conditions to the
consummation of the transactions contemplated hereby not to be satisfied or that
renders or will render untrue any representation or warranty of Buyer or the
Company contained in this Agreement. Each of Buyer and the Company also will
notify the others in writing of any violation or breach, as soon as practical
after it becomes known to such party, of any representation, warranty, covenant
or agreement made by Buyer or the Company. No notice given pursuant to this
Section 8.11 shall have any effect on the representations, warranties, covenants
or agreements contained in this Agreement for purposes of determining
satisfaction of any condition contained herein.
 
    8.12  FULFILLMENT OF CONDITIONS.  Subject to the terms and conditions of
this Agreement, each of Buyer and the Company will take or cause to be taken all
commercially reasonable steps necessary or desirable and proceed diligently and
in good faith to satisfy each condition to the other's obligations contained in
this Agreement and to consummate and make effective the transactions
contemplated by this Agreement, and neither Buyer nor the Company will, nor will
they permit any of their Subsidiaries to, take or fail to take any action that
could be reasonably expected to result in the nonfulfillment of any such
condition; provided that, neither Buyer nor any of its Subsidiaries shall be
required to take any action, or refrain from taking any action, which by so
doing could reasonably be expected prior to or after the Closing to have a
material adverse effect on either Buyer and its Subsidiaries, taken as a whole,
or the Company and its Subsidiaries, taken as a whole, or otherwise result in a
material diminution of the benefits of the transactions contemplated by this
Agreement to Buyer.
 
    8.13  REPRESENTATION ON BUYER'S BOARD OF DIRECTORS.  At or prior to Closing,
Buyer shall increase the size of its Board of Directors by two members to 14
members. At Closing, Buyer shall use its best efforts to nominate the following
individuals to Buyer's Board of Directors: Ian G. Sinclair and Robert A. Spass.
At Buyer's 1998 Annual Meeting of stockholders, Buyer shall use its best efforts
to nominate the aforesaid individuals to Buyer's Board of Directors and cause
them to be elected to one full three-year term.
 
    8.14  SELLING STOCKHOLDERS UNDERTAKING.  The Company shall use its best
efforts to cause each of the stockholders listed on Schedules 8.14(a) and (b) to
this Agreement (collectively, the "Selling Stockholders") to execute and deliver
to Buyer an irrevocable undertaking (the "Undertaking") with respect to the
Offer substantially in the form of Exhibit A to this Agreement and, where so
indicated on Schedules 8.14(a) and 8.14(b) to this Agreement, accompanied by
letters of direction and an opinion of counsel with respect to such letters.
Simultaneous with the execution of this Agreement, the stockholders of the
Company listed on Schedule 8.14(a) to this Agreement shall have executed and
delivered to Buyer the Undertaking and any such letters and opinions. The
Company shall continue to use its best efforts to cause each of the Selling
Stockholders listed on Schedule 8.14(b) to this Agreement to execute and deliver
the Undertaking and any such letters and opinions. Notwithstanding the
foregoing, Buyer and the Company agree that the Undertaking to be executed by
J.P. Morgan Capital Corp. shall contain such additional terms as Buyer, the
Company and J.P. Morgan Capital Corp. shall agree upon.
 
    8.15  AFFILIATES AGREEMENT.  The Company shall use its best efforts to cause
each of the Persons listed on Schedule 8.15 to this Agreement (collectively, the
"Designated Affiliates") to execute and deliver to Buyer, as soon as possible
but in any event not later than 30 days prior to the Closing, an affiliates
agreement substantially in the form of Exhibit B to this Agreement (the
"Affiliates Agreement").
 
                                    APP-A-33
<PAGE>
                                   ARTICLE IX
                                   CONDITIONS
 
    9.01  MUTUAL CONDITIONS TO CLOSING.  Prior to and as of the Closing, each of
the following conditions shall have been fulfilled (other than conditions which
have been waived or modified upon the written consent of both Buyer and the
Company):
 
        (a)  STOCKHOLDER APPROVAL.  This Agreement and the transactions
    contemplated hereby shall have been adopted by the requisite vote of the
    stockholders of Buyer under the General Corporation Law of the State of
    Delaware (the "DGCL").
 
        (b)  MINIMUM CONDITION.  Shares of Company Common Stock representing at
    least ninety percent on a fully diluted basis in nominal value of voting
    shares of Company Common Stock, and all of the non-voting shares of Company
    Common Stock, outstanding and not previously tendered to Buyer by agreement
    shall have been validly tendered and not properly withdrawn prior to the
    expiration of the Offer (the "Minimum Condition"); provided, however, that
    Buyer and the Company hereby agree that any waiver of the terms and
    conditions of this subparagraph (b) shall not reduce the ninety percent
    threshold of this subparagraph (b) to an amount which is fifty percent or
    less.
 
        (c)  HSR ACT.  Any waiting period (and any extension thereof) applicable
    to the consummation of the transactions contemplated by this Agreement under
    the HSR Act shall have expired or been terminated.
 
        (d)  GOVERNMENTAL AND REGULATORY AND OTHER CONSENTS AND APPROVALS.  All
    authorizations, orders, grants, recognitions, confirmations, permits,
    consents, clearances, permissions, approvals, waivers and actions of,
    filings with and notices to, any Governmental or Regulatory Authority or any
    other public or private third parties required of Buyer, the Company or any
    of their Subsidiaries to consummate the transactions contemplated by this
    Agreement, other than those the failure of which to be obtained or taken
    could not be reasonably expected to have a material adverse effect on Buyer
    and its Subsidiaries or the Company and its Subsidiaries, in each case taken
    as a whole, or on the ability of Buyer and the Company to consummate the
    transactions contemplated by this Agreement shall have been obtained or
    taken; provided that no such permit, consent, approval, waiver or action
    shall be subject to any condition which could reasonably be expected prior
    to or following the Closing to have a material adverse effect on Buyer and
    its Subsidiaries taken as a whole, or on the Company and its Subsidiaries
    taken as a whole, or otherwise result in a material diminution of the
    benefits of the transactions contemplated by this Agreement to Buyer.
 
        (e)  CERTAIN U.K. CONSENTS AND APPROVALS.
 
        (i) the UK Office of Fair Trading shall have indicated, in terms
    reasonably satisfactory to Buyer, that the Secretary of State for Trade and
    Industry does not intend to refer the proposed acquisition of the Company
    Common Stock or any matter relating thereto to the Monopolies and Mergers
    Commission;
 
        (ii) the UK Secretary of State for Trade and Industry shall have
    confirmed, in terms reasonably satisfactory to Buyer, in accordance with
    Section 61 of the UK Insurance Companies Act 1982 that there is no objection
    to Buyer and any relevant stockholders or officers of Buyer becoming
    controllers of the Company or, in the absence of such confirmation in
    relation to any such person, the period during which the Secretary of State
    may serve a notice of objection pursuant to Section 61 of the UK Insurance
    Companies Act 1982 in relation to such person not having elapsed without the
    Secretary of State having served any such notice of objection;
 
                                    APP-A-34
<PAGE>
       (iii) the Council of Lloyd's shall have approved, in terms reasonably
    satisfactory to Buyer, Buyer and any relevant stockholders of Buyer as
    controllers of Jago Capital Limited (a Lloyd's corporate member) and of Jago
    Managing Agency Limited (a Lloyd's managing agency); and
 
        (iv) the UK Inland Revenue shall have issued notification pursuant to
    Section 138 of the Taxation of Chargeable Gains Act 1992 that it is
    satisfied that the transactions contemplated by this Agreement will be
    effected for bona fide commercial reasons and will not form part of any such
    scheme or arrangements as are mentioned in Section 137 of the Taxation and
    Chargeable Gains Act of 1992.
 
        (f)  EFFECTIVENESS OF REGISTRATION STATEMENT.  The Registration
    Statement shall have become effective and shall be effective at the Closing,
    and no stop order suspending effectiveness of the Registration Statement
    shall have been issued, no action, suit, proceeding or investigation by the
    SEC to suspend the effectiveness thereof shall have been initiated and be
    continuing, or, to the knowledge of Buyer or the Company, threatened, and
    all necessary approvals under state securities laws relating to the issuance
    or trading of the Common Stock to be issued to the stockholders of the
    Company in connection with the Offer shall have been received.
 
        (g)  NYSE LISTING.  The shares of Common Stock to be issued pursuant to
    this Agreement and such other shares required to be reserved for issuance
    pursuant to this Agreement, if any, shall have been approved for listing on
    the NYSE, subject to official notice of issuance.
 
        (h)  COMPANY FAIRNESS OPINION.  The Company shall have received the
    opinion of Donaldson, Lufkin & Jenrette Securities Corporation, dated the
    date hereof, to the effect that, as of the date hereof, the Exchange Ratio
    to be offered to the stockholders of the Company is fair from a financial
    point of view to the stockholders of the Company, a true and complete copy
    of such opinion has been delivered to Buyer prior to the execution of this
    Agreement and such opinion has not been withdrawn.
 
        (i)  TAX OPINION.  The Company shall have received the opinion of Paul,
    Weiss, Rifkind, Wharton & Garrison with respect to the qualification of the
    Transaction under Section 368(a)(1)(B) of the Code; a true and complete copy
    of such opinion will have been provided to Buyer prior to the Closing, and
    such opinion shall not have been withdrawn.
 
    9.02  CONDITIONS TO BUYER'S OBLIGATION.  The obligation of Buyer to effect
the transactions contemplated by this Agreement is subject to the fulfillment,
or waiver by Buyer, at or prior to the Closing, of each of the following
conditions:
 
        (a)  NO INJUNCTIONS OR RESTRAINTS.  There shall not have been any law or
    order promulgated, entered, enforced, enacted, issued or deemed applicable
    to the transactions contemplated by this Agreement by any court of competent
    jurisdiction or other competent Governmental or Regulatory Authority which,
    directly or indirectly, (1) prohibits, or imposes any material limitations
    on, Buyer's ownership or operation (or that of any of its Subsidiaries or
    affiliates) of any portion of its or the Company's or any of the Company's
    Subsidiaries' businesses or assets which is material to the business of the
    Company and its Subsidiaries taken as a whole, or material to the business
    of Buyer and its Subsidiaries taken as a whole, or compels Buyer (or its
    Subsidiaries or affiliates) to dispose of or hold separate any portion of
    its or the Company's or any of the Company's Subsidiaries' business or
    assets which is material to the business of the Company and its Subsidiaries
    taken as a whole, or material to the business of Buyer and its Subsidiaries
    taken as a whole, or otherwise results in a material diminution of the
    benefits of the transactions contemplated by this Agreement to Buyer, (2)
    prohibits, restrains or makes illegal any of the transactions contemplated
    by this Agreement, (3) imposes material limitations on the ability of Buyer
    (or any of its Subsidiaries or affiliates) effectively to acquire or to hold
    or to exercise full rights of ownership of the shares of Company Common
    Stock including, without limitation, the right to vote such shares of
    Company Common Stock on all matters properly presented to the Company's
    stockholders, (4) imposes limitations on the ability of Buyer (or
 
                                    APP-A-35
<PAGE>
    any of its Subsidiaries or affiliates) effectively to control in any
    material respect any material portion of the business or assets of the
    Company and its Subsidiaries taken as a whole, or any material portion of
    the business or assets of Buyer and its Subsidiaries taken as a whole, or
    (5) has the effect of making illegal or otherwise restricting, preventing or
    prohibiting consummation of the transactions contemplated by this Agreement.
 
        (b)  LITIGATION.  There shall be no instituted or pending action or
    proceeding (whether civil or criminal) before any Person or Governmental or
    Regulatory Authority (or any such action threatened by any Person or
    Governmental or Regulatory Authority) which (x) in the case of any such
    action or proceeding brought by any Governmental or Regulatory Authority,
    seeks any order, decree or injunction having any effect set forth in (a)
    above or (y) in the case of any such action or proceeding brought by any
    other Person, could reasonably be expected to result in any order, decree or
    injunction having any effect set forth in (a) above.
 
        (c)  MARKET CONDITIONS.  There shall not have occurred and be continuing
    (1) any general suspension of trading in, or limitation on prices for,
    securities on any United States national securities exchange or in the
    over-the-counter market, (2) a declaration of a banking moratorium or any
    suspension of payments in respect of banks in the United States or the
    United Kingdom (whether or not mandatory), (3) any limitation (whether or
    not mandatory) by any Governmental or Regulatory Authority on the extension
    of credit by banks or other financial institutions, (4) a commencement of a
    war or armed hostilities or other national or international crisis directly
    or indirectly involving the United States having a significant adverse
    effect on the functionality of the financial markets in the United States or
    (5) in the case of any of the foregoing existing on the date of this
    Agreement, in the good faith judgment of Buyer a material acceleration or
    worsening thereof.
 
        (d)  REPRESENTATIONS AND WARRANTIES.  The representations and warranties
    made by the Company in this Agreement that are subject to, or qualified by,
    "material adverse effect," "material adverse change" or other materiality
    qualification shall be true and correct, and the representations and
    warranties made by the Company in this Agreement that are not so qualified
    shall be true and correct except in any respect which could not reasonably
    be expected to have a material adverse effect on the Company and its
    Subsidiaries taken as a whole, in each case when made and as of the Closing.
 
        (e)  PERFORMANCE OF OBLIGATIONS OF THE COMPANY.  The Company shall have
    performed and complied with in all material respects (without any reference
    to any materiality qualification contained therein) all obligations and
    covenants required to be performed or complied with by it under this
    Agreement on or before the Closing.
 
        (f)  BUYER FAIRNESS OPINION.  Buyer shall have received the opinion of
    Smith Barney Inc., dated the date hereof, to the effect that, as of the date
    hereof, the Exchange Ratio offered by Buyer pursuant to the Offer is fair to
    Buyer from a financial point of view, a true and complete copy of such
    opinion has been delivered to the Company prior to the execution of this
    Agreement and such opinion has not been withdrawn.
 
        (g)  SELLING STOCKHOLDER UNDERTAKING.  Each of the Selling Stockholders
    shall have executed and delivered to Buyer an Undertaking along with the
    letters of direction and opinions of counsel referred to in Section 8.14,
    and all such Undertakings, letters of direction and opinions shall be in
    full force and effect and shall not have been withdrawn.
 
        (h)  [INTENTIONALLY OMITTED]
 
        (i)  POOLING TREATMENT.  Neither the Company nor its affiliates shall
    have taken any action which has prevented or would prevent Buyer from
    treating the acquisition of the Company as a pooling-of-interests in
    accordance with United States generally accepted accounting principles.
 
                                    APP-A-36
<PAGE>
        (j)  ACQUISITION AGREEMENT.  This Agreement shall not have been
    terminated in accordance with its terms, and shall remain in full force and
    effect.
 
        (k)  COMPANY AMENDMENT.  The stockholders of the Company shall have
    approved and adopted the Company Amendment at the Company Stockholders'
    Meeting, and such Company Amendment shall take effect as of the Closing.
 
        (l)  AFFILIATES AGREEMENT.  Each of the Designated Affiliates shall have
    executed and delivered to Buyer an Affiliates Agreement; there shall have
    been no breaches of any of the terms of the Affiliates Agreements by any
    Designated Affiliate prior to the Closing; and the Affiliates Agreements
    shall be in full force and effect.
 
    9.03  ADDITIONAL CONDITIONS TO CLOSING.  Prior to and as of the Closing,
each of the following conditions shall have been fulfilled (unless waived by the
Company):
 
        (a)  REPRESENTATIONS AND WARRANTIES.  The representations and warranties
    made by Buyer in this Agreement that are subject to, or qualified by,
    "material adverse effect," "material adverse change" or other materiality
    qualification shall be true and correct, and the representations and
    warranties made by Buyer in this Agreement that are not so qualified shall
    be true and correct except in any respect which could not reasonably be
    expected to have a material adverse effect on Buyer and its Subsidiaries
    taken as a whole, in each case when made and as of the Closing.
 
        (b)  PERFORMANCE OF OBLIGATIONS OF BUYER.  Buyer shall have performed
    and complied with in all material respects (without any reference to any
    materiality qualification contained therein) all obligations and covenants
    required to be performed or complied with by it under this Agreement on or
    before the Closing.
 
                                   ARTICLE X
                       TERMINATION, AMENDMENT AND WAIVER
 
    10.01  TERMINATION.  This Agreement may be terminated, and the transactions
contemplated hereby may be abandoned, at any time prior to the Closing, subject
to obtaining any necessary consent from the Panel on Takeovers and Mergers in
the United Kingdom (the "Takeover Panel"):
 
        (a)  By mutual written agreement of the parties hereto duly authorized
    by action taken by or on behalf of their respective Boards of Directors;
 
        (b)  By either the Company or Buyer upon notification to the
    non-terminating party by the terminating party:
 
            (i) at any time after December 31, 1997 if the transactions
       contemplated by this Agreement have not been consummated and the failure
       to consummate the foregoing is not caused by a breach of this Agreement
       by the terminating party;
 
            (ii) if the Offer is commenced and shall have terminated or expired
       in accordance with its terms without Buyer having accepted for exchange
       and having exchanged any shares of Company Common Stock pursuant to the
       Offer; provided, however, that Buyer may not terminate this Agreement
       pursuant to this Section 10.01(b)(ii) if Buyer's termination of, or
       failure to accept for exchange or to exchange any shares of Company
       Common Stock tendered pursuant to, the Offer does not follow the
       occurrence, or failure to occur, as the case may be, of any condition set
       forth in Sections 9.01 or 9.02 or if Buyer is otherwise in breach of the
       terms of the Offer or this Agreement;
 
           (iii) if any court of competent jurisdiction or other competent
       Governmental or Regulatory Authority shall have issued an order making
       illegal or otherwise restricting, preventing or
 
                                    APP-A-37
<PAGE>
       prohibiting any of the transactions contemplated by this Agreement and
       such order shall have become final and nonappealable; or
 
            (iv) if a Higher Competing Offer is made or a firm intention to make
       a Higher Competing Offer is publicly announced and Buyer has not
       announced a Higher Revised Offer before the Revision Deadline (as such
       terms are defined in the Undertaking), and the payment of the $5,000,000
       referenced in paragraph 18.4 of the Undertaking has been made to Buyer;
       or
 
        (c)  By the Company if (i) there has been a material breach of any
    representation, warranty, covenant or agreement on the part of Buyer set
    forth in this Agreement, which breach is not curable or, if curable, has not
    been cured within 30 days following receipt by Buyer of notice of such
    breach from the Company; (ii) the Offer has not been timely commenced in
    accordance with Section 11.01(a); or (iii) all of the conditions in Article
    IX have been satisfied or, if applicable, waived and the Closing has not
    occurred substantially in accordance with Section 2.01; or
 
        (d)  By Buyer, prior to Closing, if there has been a material breach of
    any representation, warranty, covenant or agreement on the part of the
    Company set forth in this Agreement which breach is not curable or, if
    curable, has not been cured within 30 days following receipt by the Company
    of notice of such breach from Buyer.
 
    10.02  EFFECT OF TERMINATION.  If this Agreement is validly terminated by
either the Company or Buyer pursuant to Section 10.01, this Agreement will
forthwith become null and void and there will be no liability or obligation on
the part of the Company or Buyer (or any of their respective Representatives or
affiliates), except that the provisions of Sections 8.07, 8.08, this Section
10.02, and paragraphs 7 and 18 of the Undertakings will continue to apply
following any such termination. Notwithstanding the foregoing, if this Agreement
is validly terminated by the Company pursuant to Section 10.01(c) due to a
breach by Buyer of Sections 5.12(c), 7.01(b)(ii)(A) or (B), 7.02(c), 8.03, 8.04,
8.12 or 8.13, Buyer shall be responsible for and shall pay promptly the
Company's Transaction Expenses and any damages it has suffered, and if this
Agreement is validly terminated by Buyer pursuant to Section 10.01(d) due to a
breach by the Company of Sections 8.04 or 8.12, the Company shall be responsible
for and shall pay promptly Buyer's Transaction Expenses and any damages it has
suffered.
 
    10.03  AMENDMENT.  This Agreement may be amended, supplemented or modified
by action taken by or on behalf of each of the respective Boards of Directors of
the parties hereto at any time prior to the Closing. No such amendment,
supplement or modification shall be effective unless set forth in a written
instrument duly executed by or on behalf of each party hereto.
 
    10.04  WAIVER.  At any time prior to the Closing any party hereto, by action
taken by or on behalf of its Board of Directors, may to the extent permitted by
applicable law and pursuant to this Agreement (i) extend the time for the
performance of any of the obligations or other acts of the other parties hereto,
(ii) waive any inaccuracies in the representations and warranties of the other
parties hereto contained herein or in any document delivered pursuant hereto or
(iii) waive compliance with any of the covenants, agreements or conditions of
the other parties hereto contained herein. No such extension or waiver shall be
effective unless set forth in a written instrument duly executed by or on behalf
of the party extending the time of performance or waiving any such inaccuracy or
non-compliance. No waiver by any party of any term or condition of this
Agreement, in any one or more instances, shall be deemed to be or construed as a
waiver of the same or any other term or condition of this Agreement on any
future occasion.
 
                                    APP-A-38
<PAGE>
                                   ARTICLE XI
                                   THE OFFER
 
    11.01  THE OFFER.
 
        (a)  TERMS OF THE OFFER.  No later than five business days after the
    date of exercise by the Company of the Tender Option (as defined in Section
    11.01(c)), Buyer shall commence (within the meaning of Rule 14d-2 under the
    Exchange Act), a tender offer (the "Offer") to acquire all of the issued and
    outstanding shares of Company Common Stock in exchange for 0.836 shares of
    Common Stock per share of Company Common Stock issued and outstanding (the
    "Exchange Ratio"); provided, however, that Buyer shall not be obligated to
    commence the Offer if, on the date Buyer would otherwise be obligated to
    commence the Offer, any of the conditions set forth in Sections 9.01(c), (f)
    or (h) or Sections 9.02(a), (b), (c), (d), (e), (f), (g), (h) or (i) are not
    then satisfied. If Buyer does not commence the Offer in reliance on the
    proviso in the preceding sentence, the Company shall have the right to
    reexercise the Tender Option in accordance with Section 11.01(c). The
    obligation of Buyer to consummate the Offer once it is commenced and to
    accept for exchange and to exchange shares of Company Common Stock tendered
    pursuant to the Offer shall be subject only to the conditions set forth in
    Article IX. Buyer expressly reserves the right to waive any such condition
    (other than the conditions specified in Section 9.01, the waiver of which
    must be consented to by the Company, and in Section 9.03, which may only be
    waived by the Company), to increase the Exchange Ratio and to make any other
    changes in the terms and conditions of the Offer. Notwithstanding the
    foregoing, no change may be made which (i) decreases the number of shares of
    Common Stock to be given in exchange per share of Company Common Stock, (ii)
    changes the form of consideration to be paid in the Offer, (iii) reduces the
    number of shares of Company Common Stock sought to be purchased in the
    Offer, (iv) imposes conditions to the Offer in addition to those set forth
    in Article IX, except those required by the City Code, the Exchange Act, the
    NYSE or any other applicable laws, rules or regulations, (v) extends the
    expiration date of the Offer or (vi) otherwise alters or amends any term of
    the Offer in any manner materially adverse to the holders of shares of
    Company Common Stock; provided, however, that subject to the right of the
    parties to terminate this Agreement pursuant to Section 10.01, the Offer may
    be extended (1) for any period to the extent required by law or by any rule,
    regulation, interpretation or position of the SEC or the staff thereof or
    the Takeover Panel applicable to the Offer, (2) for one or more periods of
    not more than ten business days, but in no event for more than a total of 60
    calendar days from the commencement of the Offer and (3) notwithstanding the
    limitation in the previous clause (2), if a Higher Competing Offer is made
    or a firm intention to make a Higher Competing Offer is publicly announced
    as contemplated by paragraph 18 of the Undertaking, for such period or
    periods as may be required to extend the Offer to the date such Higher
    Competing Offer expires or is terminated; provided, however, that in no
    event shall the Offer extend beyond December 31, 1997. Assuming the prior
    satisfaction or waiver of the conditions of the Offer and subject to the
    foregoing right to extend the Offer, Buyer shall deliver shares of Common
    Stock in exchange for shares of Company Common Stock tendered pursuant to
    Article III as soon as practicable in accordance therewith and as may be
    required by the City Code, the Exchange Act, the NYSE or any other
    applicable laws, rules or regulations.
 
        (b)  OFFER DOCUMENTS.  As soon as practicable on the date of
    commencement of the Offer, Buyer shall file with the SEC a Tender Offer
    Statement on Schedule 14D-1 promulgated under the Exchange Act (together
    with all amendments and supplements thereto, the "Schedule 14D-1") with
    respect to the Offer, and take such steps as are reasonably necessary to
    cause the Offer to Exchange to be disseminated to the holders of shares of
    Company Common Stock as and to the extent required by applicable federal
    securities laws. The Schedule 14D-1 shall contain an offer to exchange (the
    "Offer to Exchange") and forms of the related letter of transmittal and any
    related summary advertisement (the Schedule 14D-1, the Offer to Exchange and
    such other documents as may be required by the City Code, the Exchange Act,
    the NYSE or any other applicable laws, rules or regulations, together with
    all
 
                                    APP-A-39
<PAGE>
    amendments and supplements thereto, the "Offer Documents"). Buyer shall use
    its best efforts to distribute such Offer Documents and any other documents
    required by law or this Agreement to all holders of shares of Company Common
    Stock. Buyer and the Company shall correct promptly any information provided
    by any of them for use in the Offer Documents which shall have become false
    or misleading, and Buyer shall take all steps necessary to cause the
    Schedule 14D-1 as so corrected to be filed with the SEC and the other Offer
    Documents as so corrected to be disseminated to holders of shares of Company
    Common Stock, in each case as and to the extent required by applicable
    federal securities laws. The Company and its counsel shall be given a
    reasonable opportunity to review and comment on the Offer Documents prior to
    their being filed with the SEC, and Buyer will provide the Company and its
    counsel in writing with any comments that Buyer receives from the SEC or its
    staff with respect to the Offer Documents promptly after receipt of any such
    comments.
 
        (c)  TENDER OPTION.  At any time after the SEC declares the Registration
    Statement effective, and prior to December 31, 1997, the Company shall have
    the right to require that Buyer commence (within the meaning of Rule 14d-2
    under the Exchange Act) the Offer (the "Tender Option"). The Tender Option
    shall be exercised by written notice to Buyer.
 
        (d)  STOCK OPTIONS.  The Offer will extend to all shares of Company
    Common Stock which may be issued as a result of the exercise of outstanding
    options with respect to Company Common Stock under the Company's existing
    stock option plans ("Company Stock Options"). Except as provided pursuant to
    Affiliate Agreements executed and delivered pursuant to Section 9.02(l), any
    holder of Company Stock Options who (i) exercises his Company Stock Options
    in whole or in part, (ii) receives Company Common Stock in connection with
    such exercise, and (iii) receives Common Stock pursuant to the Offer in
    exchange for that Company Common Stock shall be under no restriction from
    the Buyer as to his ability to sell such Common Stock.
 
    11.02  COMPANY ACTIONS.
 
        (a)  On the date the Offer Documents are filed with the SEC, the Company
    shall file with the SEC a Solicitation/Recommendation Statement on Schedule
    14D-9 promulgated under the Exchange Act (together with all amendments and
    supplements thereto, the "Schedule 14D-9") containing the recommendation of
    the Board of Directors of the Company described in Section 1.01, except to
    the extent the Board of Directors is legally obligated in the opinion of
    counsel (which opinion shall be communicated to Buyer), to alter such
    recommendation, and shall take such steps as are necessary to cause the
    Schedule 14D-9 to be disseminated to the holders of shares of Company Common
    Stock as and to the extent required by the City Code, the NYSE or any other
    applicable laws, rules and regulations, including, without limitation,
    applicable federal securities laws. The Company and Buyer shall amend or
    correct promptly any information provided by any of them for use in the
    Schedule 14D-9 which shall have become false or misleading, and the Company
    shall take all steps necessary to cause the Schedule 14D-9 as so amended or
    corrected to be filed with the SEC and disseminated to holders of shares of
    Company Common Stock, in each case as and to the extent required by
    applicable federal securities laws. Buyer and its counsel shall be given a
    reasonable opportunity to review and comment on the Schedule 14D-9 prior to
    its being filed with the SEC, and the Company will provide Buyer and its
    counsel in writing with any comments that the Company receives from the SEC
    or its staff with respect to the Schedule 14D-9 promptly after receipt of
    any such comments.
 
        (b)  In connection with the Offer, the Company shall cause the
    Depositary to furnish Buyer promptly with mailing labels containing the
    names and addresses of all record holders of shares of Company Common Stock
    and with security position listings of shares of Company Common Stock held
    in stock depositories, each as of a recent date, together with all other
    available listings and computer files containing names, addresses and
    security position listings of record holders and beneficial owners of shares
    of Company Common Stock. The Company shall furnish Buyer with such
    additional information, including, without limitation, updated listings and
    files of stockholders,
 
                                    APP-A-40
<PAGE>
    mailing labels and security position listings and such other assistance as
    Buyer or its agents may reasonably request in communicating the Offer to
    record and beneficial holders of shares of Company Common Stock. Subject to
    the requirements of the City Code, the Securities Act, the Exchange Act, the
    NYSE and any other applicable laws, rules or regulations, and except for
    such steps as are necessary to disseminate the Offer Documents and any other
    documents necessary to consummate the transactions contemplated by this
    Agreement, Buyer shall hold in confidence the information contained in such
    labels, listings and files, shall use such information only in connection
    with the transactions contemplated by this Agreement, and, if this Agreement
    shall be terminated in accordance with Section 10.01, shall deliver to the
    Company all copies of, and any extracts or summaries from, such information
    then in their possession or control.
 
        (c)  In connection with the Offer, the Company will furnish Buyer with
    such information (which will be treated and held in confidence by Buyer
    except to the extent required to be disclosed pursuant to the Offer or this
    Agreement) and assistance as Buyer or its Representatives may reasonably
    request in connection with the preparation of the Offer and communicating
    the Offer to the record and beneficial holders of shares of Company Common
    Stock and Company Deferred Stock.
 
                                  ARTICLE XII
                               GENERAL PROVISIONS
 
    12.01  NON-SURVIVAL OF REPRESENTATIONS, WARRANTIES, COVENANTS AND
AGREEMENTS.  The representations, warranties, covenants and agreements contained
in this Agreement or in any instrument delivered pursuant to this Agreement
shall not survive the consummation of the transactions contemplated hereby but
shall terminate at the Closing, except for the agreements contained in Article
III, Sections 4.12(i), 5.12(c), 6.03, 7.02, 8.06, 8.07 and 8.08 and this Article
XII of this Agreement, and in paragraphs 3, 4.3, 4.4, 15 and 19 of the
Undertakings, which shall survive the Closing.
 
    12.02  NOTICES.  All notices, requests and other communications hereunder
must be in writing and will be deemed to have been duly given only if delivered
personally or by facsimile transmission or mailed (first class postage prepaid)
or delivered by a nationally recognized overnight delivery service to the
parties at the following addresses or facsimile numbers:
 
                   If to Buyer, to:
 
                   MMI Companies, Inc.
                   540 Lake Cook Road
                   Deerfield, Illinois 60015-5290
                   Facsimile: (847) 940-2372
                   Attn: Wayne A. Sinclair
 
                   with a copy to:
 
                   Wildman, Harrold, Allen & Dixon
                   225 West Wacker Drive
                   Chicago, Illinois 60606
                   Facsimile No.: (312) 201-2555
                   Attn: Jerald P. Esrick
 
                   and to:
 
                   Clifford Chance
                   200 Aldersgate Street
                   London EC1A 4JJ England
                   Facsimile No.: +44 171 600 5555
                   Attn: Jeremy Brownlow
 
                                    APP-A-41
<PAGE>
                   If to the Company, to:
 
                   Unionamerica Holdings plc
                   London Underwriting Centre
                   3 Minster Court, Mincing Lane
                   London EC3R 7DD
                   Facsimile No.: +44 171 617 5993
                   Attn: Trevor R. Smith
 
                   with a copy to:
 
                   LeBoeuf, Lamb, Greene & MacRae, L.L.P.
                   125 West 55th Street
                   New York, New York 10019
                   Facsimile No.: (212) 424-8500
                   Attn: Joseph L. Seiler III
 
                   and to:
 
                   Lovell White Durrant
                   65 Holborn Viaduct
                   London, England EC1A 2DY
                   Facsimile No.: +44 171 248 4212
                   Attn: John Davidson
 
                   and to:
 
                   Paul, Weiss, Rifkind, Wharton & Garrison
                   1285 Avenue of the Americas
                   New York, New York 10019-6064
                   Facsimile No.: (212) 757-3990
                   Attn: David R. Sicular
 
All such notices, requests and other communications will (i) if delivered
personally to the address as provided in this Section 12.02, be deemed given
upon delivery, (ii) if delivered by facsimile transmission to the facsimile
number as provided in this Section 12.02, be deemed given upon receipt, and
(iii) if delivered by mail or overnight delivery service in the manner described
above to the address as provided in this Section 12.02, be deemed given upon
receipt (in each case regardless of whether such notice, request or other
communication is received by any other Person to whom a copy of such notice,
request or other communication is to be delivered pursuant to this Section
12.02). Any party from time to time may change its address, facsimile number or
other information for the purpose of notices to that party by giving notice
specifying such change to the other parties hereto.
 
    12.03  ENTIRE AGREEMENT; INCORPORATION OF EXHIBITS.  This Agreement
(together with all Exhibits and Schedules hereto which are incorporated herein
by this reference) supersedes all prior discussions and agreements among the
parties hereto with respect to the subject matter hereof and contains the sole
and entire agreement among the parties hereto with respect to the subject matter
hereof.
 
                                    APP-A-42
<PAGE>
    12.04  PUBLIC ANNOUNCEMENTS.  Except as otherwise required by law or the
rules of any applicable securities exchange or national market system, so long
as this Agreement is in effect: (i) the Company will not, and will not permit
any of its Representatives to, issue or cause the publication of any press
release or make any other public announcement with respect to the transactions
contemplated by this Agreement without the consent of Buyer, which shall not be
unreasonably withheld or delayed; and (ii) Buyer will not, and will not permit
any of its Representatives to, issue or cause the publication of any press
release or make any other public announcement with respect to the transactions
contemplated by this Agreement without consulting the Company prior thereto.
Buyer and the Company will cooperate with each other in the development and
distribution of all press releases and other public announcements with respect
to this Agreement and the transactions contemplated hereby, and will furnish the
others with drafts of any such releases and announcements as far in advance as
practicable. Buyer and the Company agree that all such announcements shall be
made in compliance, where appropriate, with the City Code, the Securities Act,
the Exchange Act, the rules of the NYSE and any other applicable laws, rules or
regulations.
 
    12.05  NO THIRD PARTY BENEFICIARY.  The terms and provisions of this
Agreement are intended solely for the benefit of each party hereto and their
respective successors or permitted assigns, and except as otherwise expressly
provided for herein, it is not the intention of the parties to confer
third-party beneficiary rights upon any other Person; except that the holders of
Company Common Stock shall be third-party beneficiaries of Sections 4.12(i),
5.12(c), 6.03 and 7.02.
 
    12.06  NO ASSIGNMENT; BINDING EFFECT.  Neither this Agreement nor any right,
interest or obligation hereunder may be assigned by any party hereto without the
prior written consent of the other parties hereto and any attempt to do so will
be void. Subject to the preceding sentence, this Agreement is binding upon,
inures to the benefit of and is enforceable by the parties hereto and their
respective permitted successors and assigns.
 
    12.07  HEADINGS.  The headings used in this Agreement have been inserted for
convenience of reference only and do not define, modify or limit the provisions
hereof.
 
    12.08  INVALID PROVISIONS.  If any provision of this Agreement is held to be
illegal, invalid or unenforceable under any present or future law or order, and
if the rights or obligations of any party hereto under this Agreement will not
be materially and adversely affected thereby, (i) such provision will be fully
severable, (ii) this Agreement will be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part hereof,
and (iii) the remaining provisions of this Agreement will remain in full force
and effect and will not be affected by the illegal, invalid or unenforceable
provision or by its severance herefrom.
 
    12.09  GOVERNING LAW.  This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware applicable to a contract
executed and performed in such State, without giving effect to the conflicts of
laws principles thereof. Notwithstanding the foregoing, the mandatory provisions
of English law and the provisions of the City Code affecting or defining the
obligations of Buyer, the Company, their stockholders or their directors in
connection with the transactions contemplated by this Agreement shall apply.
 
    12.10  ENFORCEMENT OF AGREEMENT.  The parties hereto agree that irreparable
damage would occur in the event that any of the provisions of this Agreement was
not performed in accordance with its specified terms or was otherwise breached.
It is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions hereof in any court of competent jurisdiction, this
being in addition to any other remedy to which they are entitled at law or in
equity.
 
    12.11  CERTAIN DEFINITIONS.  As used in this Agreement:
 
        "Act of 1992" has the meaning set forth in Section 4.12(b)(i).
 
                                    APP-A-43
<PAGE>
        "Acquisition Information" has the meaning set forth in Section 4.22.
 
        "ADSs" has the meaning set forth in the first recital to this Agreement.
 
        "affiliate" as applied to any Person, means any other Person directly or
    indirectly controlling, controlled by, or under common control with, that
    Person; for purposes of this definition, "control" (including, with
    correlative meanings, the terms "controlling," "controlled by" and "under
    common control with"), as applied to any Person, means the possession,
    directly or indirectly, of the power to direct or cause the direction of the
    management and policies of that Person, whether through the ownership of
    voting securities, by contract or otherwise.
 
        "Affiliates Agreement" has the meaning set forth in Section 8.15.
 
        "Agreement" has the meaning set forth in the preamble to this Agreement.
 
        "Alternative Proposal" has the meaning set forth in Section 6.02.
 
        "Antitrust Division" has the meaning set forth in Section 8.04.
 
        "Balance Sheet Date" has the meaning set forth in Section 4.12(a).
 
        To "beneficially" own securities means such Person would be the
    beneficial owner of such securities under Rule 13d-3 under the Exchange Act,
    including securities which such Person has the right to acquire (whether
    such right is exercisable immediately or only after the passage of time).
 
        "business day" means a day other than Saturday, Sunday or any day on
    which banks located in the State of New York, the State of Illinois or
    London, England are authorized or obligated to close.
 
        "Buy Back" has the meaning set forth in Section 5.12(c)(ii).
 
        "Buyer" has the meaning set forth in the preamble to this Agreement.
 
        "Buyer Employee Benefit Plan" has the meaning set forth in Section
    5.13(b)(i).
 
        "Buyer Financial Statements" has the meaning set forth in Section 5.05.
 
        "Buyer Permits" has the meaning set forth in Section 5.10.
 
        "Buyer Proxy Statement" has the meaning set forth in Section 5.09(a).
 
        "Buyer SEC Reports" has the meaning set forth in Section 5.05.
 
        "Buyer Stockholders' Meeting" has the meaning set forth in Section 8.03.
 
        "Buyer's Designees" has the meaning set forth in Section 1.02(a).
 
        "Cap" has the meaning set forth in Section 8.06(b).
 
        "City Code" has the meaning set forth in Section 6.02.
 
        "Closing" has the meaning set forth in Section 2.01.
 
        "Closing Date" has the meaning set forth in Section 2.01.
 
        "Code" has the meaning set forth in the second recital to this
    Agreement.
 
        "Common Stock" has the meaning set forth in the second recital to this
    Agreement.
 
        "Company" has the meaning set forth in the preamble to this Agreement.
 
        "Company Amendment" has the meaning set forth in Section 6.04.
 
        "Company Certificates" has the meaning set forth in Section 3.01(b).
 
        "Company Common Stock" has the meaning set forth in the first recital to
    this Agreement.
 
                                    APP-A-44
<PAGE>
        "Company Deferred Stock" has the meaning set forth in the first recital
    to this Agreement.
 
        "Company Financial Statements" has the meaning set forth in Section
    4.05.
 
        "Company Permits" has the meaning set forth in Section 4.10.
 
        "Company SEC Reports" has the meaning set forth in Section 4.05.
 
        "Company Stock Options" has the meaning set forth in Section 11.01(d).
 
        "Company Stockholders Meeting" has the meaning set forth in Section
    6.04.
 
        "Company Voting Debt" has the meaning set forth in Section 4.02(a).
 
        "Confidential Information" means any information concerning the
    businesses and affairs of Buyer, the Company or any of their respective
    Subsidiaries, as appropriate, that is not already generally available to the
    public.
 
        "Contracts" has the meaning set forth in Section 4.04(a).
 
        "Designated Affiliate" has the meaning set forth in Section 8.15.
 
        "Depositary" means Morgan Guaranty Trust Company of New York, as
    Depositary under the Deposit Agreement dated as of December 1, 1995, by and
    among the Company, Morgan Guaranty Trust Company of New York, as Depositary,
    and holders of American Depositary Receipts (as defined therein), as such
    agreement is amended or restated from time to time.
 
        "DGCL" has the meaning set forth in Section 9.01(a).
 
        "Disclosed Schemes" has the meaning set forth in Section 4.13(a).
 
        "Employee" has the meaning set forth in Section 4.13(a).
 
        "ERISA" has the meaning set forth in Section 5.13(a).
 
        "Event" has the meaning set forth in Section 4.12(a).
 
        "Excess Shares" has the meaning set forth in Section 3.01(c).
 
        "Excess Shares Trust" has the meaning set forth in Section 3.01(c).
 
        "Exchange Act" has the meaning set forth in Section 1.02(b).
 
        "Exchange Agent" has the meaning set forth in Section 3.01(a).
 
        "Exchange Fund" has the meaning set forth in Section 3.01(a).
 
        "Exchange Ratio" has the meaning set forth in Section 11.01(a).
 
        "FTC" has the meaning set forth in Section 8.04.
 
        "Governmental or Regulatory Authority" has the meaning set forth in
    Section 4.04(a).
 
        "Group Relief" has the meaning set forth in Section 4.12(a).
 
        "HSR Act" has the meaning set forth in Section 4.04(b).
 
        "Indemnified Parties" has the meaning set forth in Section 8.06(a).
 
        "Intellectual Property" means patents, patent applications, trademarks,
    trade names, trademark registrations, service marks, service names, logos,
    copyrights, copyright registrations and applications therefor, and licenses
    or other rights in respect thereof.
 
        "knowledge" means actual knowledge of executive officers of the Company
    or Buyer or, where appropriate, certain officers of their respective
    Subsidiaries.
 
                                    APP-A-45
<PAGE>
        "laws" has the meaning set forth in Section 4.04(b).
 
        "Lien" has the meaning set forth in Section 4.02(b).
 
        Any reference to any event, change, breach or effect being "material" or
    "materially adverse" or having a "material adverse effect" on or with
    respect to an entity (or group of entities taken as a whole) means such
    event, change or effect is material or materially adverse, as the case may
    be, to the business, financial condition or results of operations of such
    entity (or of such group of entities taken as a whole).
 
        "Material Contracts" has the meaning set forth in Section 4.19.
 
        "Minimum Condition" has the meaning set forth in Section 9.01(b).
 
        "NYSE" has the meaning set forth in Section 3.01(c).
 
        "Offer" has the meaning set forth in Section 11.01(a).
 
        "Offer Consideration" has the meaning set forth in Section 11.01(a).
 
        "Offer Documents" has the meaning set forth in Section 11.01(b).
 
        "Offer to Exchange" has the meaning set forth in Section 11.01(b).
 
        "Options" has the meaning set forth in Section 4.02(a).
 
        "orders" has the meaning set forth in Section 4.04(a).
 
        "Ordinary Course of Business" means the ordinary course of business
    consistent with past custom and practice.
 
        "Person" means an individual, partnership, corporation, limited
    liability company, association, joint stock company, trust, joint venture,
    unincorporated association, or governmental entity (or any department,
    agency or political subdivision thereof) or any other entity.
 
        "Plan" has the meaning set forth in Section 5.13(b)(ii).
 
        "Preferred Stock" has the meaning set forth in Section 5.02(a).
 
        "Properties" has the meaning set forth in Section 4.17(b).
 
        "Registration Statement" has the meaning set forth in Section 5.04(b).
 
        "Relief" has the meaning set forth in Section 4.12(a).
 
        "Representatives" of any entity means such entity's directors, officers,
    employees, legal, investment banking and financial advisors, accountants and
    any other agents and representatives.
 
        "Return" has the meaning set forth in Section 4.12(b).
 
        "Schedule 14D-1" has the meaning set forth in Section 11.01(b).
 
        "Schedule 14D-9" has the meaning set forth in Section 11.02(a).
 
        "SEC" has the meaning set forth in Section 4.04(b).
 
        "Security Interest" means any mortgage, pledge, lien, encumbrance,
    charge or other security interest, other than (a) mechanic's, materialmen's
    and similar liens, (b) liens for taxes not yet due and payable or for taxes
    that the taxpayer is contesting in good faith through appropriate
    proceedings, (c) purchase money liens and liens securing rental payments
    under capital lease arrangements and (d) other liens arising in the Ordinary
    Course of Business and not incurred in connection with the borrowing of
    money.
 
                                    APP-A-46
<PAGE>
        "Securities Act" has the meaning set forth in Section 4.05.
 
        "Selling Stockholders" has the meaning set forth in Section 8.14.
 
        "Stockholders' Approval" has the meaning set forth in Section 8.03.
 
        "Subsidiary" means, with respect to any party, any corporation or other
    organization, whether incorporated or unincorporated, of which more than
    fifty percent (50%) of either the equity interests in, or the voting control
    of, such corporation or other organization is, directly or indirectly
    through Subsidiaries or otherwise, beneficially owned by such party.
 
        "Takeover Panel" has the meaning set forth in Section 10.01.
 
        "Tax" has the meaning set forth in Section 4.12(a).
 
        "Tax Authority" has the meaning set forth in Section 4.12(a).
 
        "taxes" has the meaning set forth in Section 5.12(b).
 
        "Taxes Act" has the meaning set forth in Section 4.12(a).
 
        "Tender Option" has the meaning set forth in Section 11.01(c).
 
        "Transaction" has the meaning set forth in the first recital to this
    Agreement.
 
        "Transaction Expenses" means the total amount actually paid by a Person
    for accounting, legal, actuarial, due diligence, financial and other
    advisors services, and Governmental or Regulatory Authority filing fees,
    each in connection with the transactions contemplated by this Agreement.
 
        "Undertaking" has the meaning set forth in Section 8.14.
 
        "VAT" has the meaning set forth in Section 4.12(a).
 
        "VAT Legislation" has the meaning set forth in Section 4.12(a).
 
        "Voting Debt" has the meaning set forth in Section 5.02(a).
 
    12.12  COUNTERPARTS.  This Agreement may be executed in any number of
counterparts, each of which will be deemed an original, but all of which
together will constitute one and the same instrument.
 
        IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
    executed by their respective duly authorized officers or other authorized
    persons, all as of the date first above written.
 
                                     MMI COMPANIES, INC.
 
                                By:  /s/ B. FREDERICK BECKER
                                     -----------------------------------------
                                     Name: B. Frederick Becker
                                     Title: Chairman and Chief Executive
                                     Officer
 
                                     UNIONAMERICA HOLDINGS PLC
 
                                By:  /s/ PETER J. COOPER
                                     -----------------------------------------
                                     Name: Peter J. Cooper
                                     Title: Chief Financial Officer
 
                                    APP-A-47
<PAGE>
                                   APPENDIX B
             OPINION OF SMITH BARNEY INC., FINANCIAL ADVISOR TO MMI
 
CONFIDENTIAL
 
June 24, 1997
The Board of Directors
MMI Companies, Inc.
540 Lake Cook Road
Deerfield, Illinois 60015
 
Members of the Board:
 
You have requested our opinion as to the fairness, from a financial point of
view, to MMI Companies, Inc. ("MMI") of the consideration proposed to be paid by
MMI pursuant to the terms and subject to the conditions set forth in an
Acquisition Agreement (the "Acquisition Agreement") to be entered into by and
among MMI and Unionamerica Holdings plc ("Unionamerica"). As more fully
described in the Acquisition Agreement, (i) MMI would acquire all of the
American Depository Shares, representing all of the ordinary shares, nominal
value $0.0448 per share, of Unionamerica (the "Unionamerica Common Stock")
through (x) an offer to purchase all of such shares of Unionamerica Common Stock
(the "Offer") and (y) the subsequent compulsory acquisition of any remaining
shares of Unionamerica Common Stock and (ii) pursuant to the Offer each
outstanding share of Unionamerica Common Stock would be exchanged for the right
to receive 0.836 shares (the "Exchange Ratio") of the common stock, par value
$0.10 per share, of MMI (the "MMI Common Stock")(collectively, the "Proposed
Transaction").
 
In arriving at our opinion, we reviewed a draft of the Acquisition Agreement and
held discussions with certain senior officers, directors and other
representatives and advisors of MMI and certain senior officers and other
representatives and advisors of Unionamerica concerning the businesses,
operations and prospects of MMI and Unionamerica. We examined certain publicly
available business and financial information relating to MMI and Unionamerica as
well as certain financial forecasts and other information and data for MMI and
Unionamerica which were provided to or otherwise discussed with us by the
respective managements of MMI and Unionamerica, including information relating
to certain strategic implications and operational benefits anticipated to result
from the Proposed Transaction. We reviewed the financial terms of the Proposed
Transaction as set forth in the Acquisition Agreement in relation to, among
other things: current and historical market prices and trading volumes of MMI
Common Stock and Unionamerica Common Stock; the historical and projected
earnings and other operating data of MMI and Unionamerica; and the
capitalization and financial condition of MMI and Unionamerica. We considered,
to the extent publicly available, the financial terms of similar transactions
recently effected which we considered relevant in evaluating the Proposed
Transaction and analyzed certain financial, stock market and other publicly
available information relating to the business of other companies whose
operations we considered relevant in evaluating those of MMI and Unionamerica.
We also evaluated the potential pro forma financial impact of the Proposed
Transaction on MMI. In addition to the foregoing, we conducted such other
analyses and examinations and considered such other financial, economic and
market criteria as we deemed appropriate in arriving at our opinion.
 
In rendering our opinion, we have assumed and relied, without independent
verification, upon the accuracy and completeness of all financial and other
information publicly available or furnished to or otherwise reviewed by or
discussed with us. We also have assumed, with your consent, that the final terms
of the Acquisition Agreement reviewed by us in draft form will not vary
materially from the draft reviewed by us. With respect to financial forecasts
and other information and data provided to or otherwise reviewed by or discussed
with us, we have been advised by the managements of MMI and Unionamerica that
such forecasts and other information and data were reasonably prepared on bases
reflecting the best currently
 
                                    APP-B-1
<PAGE>
available estimates and judgments of the respective managements of MMI and
Unionamerica as to the future financial performance of MMI and Unionamerica and
the strategic implications and operational benefits anticipated to result from
the Proposed Transaction. We have assumed, with your consent, that the Proposed
Transaction will be treated as a pooling of interests in accordance with GAAP
and as a tax-free reorganization for federal income tax purposes. Our opinion,
as set forth herein, relates to the relative values of MMI and Unionamerica. We
are not expressing any opinion as to what the value of the MMI Common Stock
actually will be when issued pursuant to the Proposed Transaction or the price
at which the MMI Common Stock will trade subsequent to the Proposed Transaction.
We have not made or, with the exception of certain reserve reports relating to
Unionamerica, been provided with an independent evaluation or appraisal of the
assets, liabilities (contingent or otherwise) or reserves of MMI or Unionamerica
nor have we made any physical inspection of the properties or assets of MMI or
Unionamerica. We have not been asked to consider, and our opinion does not
address, the relative merits of the Proposed Transaction as compared to any
alternative business strategies that might exist for MMI or the effect of any
other transaction in which MMI might engage. Our opinion is necessarily based
upon information available to us, and financial, stock market and other
conditions and circumstances existing and disclosed to us, as of the date
hereof.
 
Smith Barney has been engaged to render financial advisory services to MMI in
connection with the Proposed Transaction and will receive a fee for such
services, a significant portion of which is contingent upon the consummation of
the Proposed Transaction. We also will receive a fee upon the delivery of this
opinion. In the ordinary course of our business, we and our affiliates may
actively trade or hold the securities of MMI and Unionamerica for our own
account or for the account of our customers and, accordingly, may at any time
hold a long or short position in such securities. We have in the past provided
financial advisory and investment banking services to MMI unrelated to the
Proposed Transaction, including serving as a managing underwriter in the initial
public offering of MMI Common Stock in June 1993 and the subsequent public
offering of MMI Common Stock in September 1996, for which services we have
received compensation. In addition, we and our affiliates (including Travelers
Group Inc. and its affiliates) may maintain relationships with MMI and
Unionamerica.
 
Our advisory services and the opinion expressed herein are provided for the
information of the Board of Directors of MMI in its evaluation of the Proposed
Transaction, and our opinion is not intended to be and does not constitute a
recommendation to any shareholder as to how such shareholder should vote on any
matter relating to the Proposed Transaction. Our opinion may not be published or
otherwise used or referred to, nor shall any public reference to Smith Barney be
made, without our prior written consent.
 
Based upon and subject to the foregoing, our experience as investment bankers,
our work as described above and other factors we deemed relevant, we are of the
opinion that, as of the date hereof, the Exchange Ratio is fair, from a
financial point of view, to MMI.
 
                                          Very truly yours,
 
                                          SMITH BARNEY INC.
 
<TABLE>
<S>                                         <C>        <C>
                                            By:        /s/ SMITH BARNEY INC.
                                                       -----------------------------------------
</TABLE>
 
                                    APP-B-2
<PAGE>
                                   APPENDIX C
        OPINION OF DONALDSON, LUFKIN & JENRETTE SECURITIES CORPORATION,
                       FINANCIAL ADVISOR TO UNIONAMERICA
 
June 25, 1997
Board of Directors
Unionamerica Holdings plc
3 Minster Court
Mincing Lane
London EC3R 7DD
 
Dear Sirs:
 
You have requested our opinion as to the fairness from a financial point of view
to the stockholders of Unionamerica Holdings plc (the "Company") of the
consideration to be received by such stockholders pursuant to the terms of the
Acquisition Agreement, dated as of June 25, 1997 (the "Agreement"), by and
between MMI Companies, Inc., a Delaware corporation ("MMI"), and the Company.
 
    Pursuant to the Agreement, MMI will commence a tender offer (the "Offer") to
acquire all of the issued and outstanding American Depositary Shares ("ADSs"),
representing all of the ordinary shares, nominal value $0.0448 per share, of the
Company (such ADSs, "Company Common Stock") for 0.836 shares (the "Exchange
Ratio") of common stock, par value $0.10 per share ("MMI Common Stock") of MMI,
per share of Company Common Stock.
 
    In arriving at our opinion, we have reviewed the Agreement. We also have
reviewed financial and other information that was publicly available or
furnished to us by the Company and MMI including information provided during
discussions with their respective managements. Included in the information
provided during discussions with the respective managements were certain
financial projections of the Company for the years ending December 31, 1997 and
December 31, 1998 prepared by the management of the Company and certain
financial projections of MMI for the years ending December 31, 1997 and December
31, 1998 prepared by the management of MMI. In addition, we have compared
certain financial and securities data of the Company and MMI with various other
companies whose securities are traded in public markets, reviewed the historical
stock prices and trading volumes of the Company Common Stock and MMI Common
Stock, reviewed prices and premiums paid in certain other business combinations
and conducted such other financial studies, analyses and investigations as we
deemed appropriate for purposes of this opinion.
 
    In rendering our opinion, we have relied upon and assumed the accuracy and
completeness of all of the financial and other information that was available to
us from public sources, that was provided to us by the Company and MMI or their
respective representatives, or that was otherwise reviewed by us. With respect
to the financial projections supplied to us, we have assumed that they have been
reasonably prepared on the basis reflecting the best currently available
estimates and judgments of the management of the Company and MMI as to the
future operating and financial performance of the Company and MMI, respectively.
We have not assumed any responsibility for making an independent evaluation of
the Company's assets or liabilities or for making any independent verification
of any of the information reviewed by us. We have relied as to certain legal
matters on advice of counsel to the Company.
 
    Our opinion is necessarily based on economic, market, financial and other
conditions as they exist on, and on the information made available to us as of,
the date of this letter. It should be understood that, although subsequent
developments may affect this opinion, we do not have any obligation to update,
revise or reaffirm this opinion. Our opinion does not address the relative
merits of the proposed Transaction and the other business strategies being
considered by the Company's Board of Directors, nor does it address
 
                                    APP-C-1
<PAGE>
the Board's decision to proceed with the proposed Transaction. Our opinion does
not constitute a recommendation to any holder of Company Common Stock as to
whether such holder should tender into the proposed Transaction or as to the
position of any holder who does not tender shares pursuant to the Offer.
 
    Donaldson, Lufkin & Jenrette Securities Corporation ("DLJ"), as part of its
investment banking services, is regularly engaged in the valuation of businesses
and securities in connection with mergers, acquisitions, underwritings, sales
and distributions of listed and unlisted securities, private placements and
valuations for estate, corporate and other purposes. DLJ has performed
investment banking and other services for the Company in the past and has been
compensated for such services.
 
    Based upon the foregoing and such other factors as we deem relevant, we are
of the opinion that the Exchange Ratio to be offered to the holders of Company
Common Stock is fair to such stockholders from a financial point of view.
 
                                          Very truly yours,
 
                                          DONALDSON, LUFKIN & JENRETTE
                                          SECURITIES CORPORATION
 
<TABLE>
<S>                                         <C>        <C>
                                            By:        /s/ MARK K. GORMLEY
                                                       -----------------------------------------
                                                       Mark K. Gormley
                                                       MANAGING DIRECTOR
</TABLE>
 
                                    APP-C-2
<PAGE>
                                   APPENDIX D
             CERTAIN MARKET, DIVIDEND AND EXCHANGE RATE INFORMATION
 
1.  MARKET AND PRICE DATA
 
       The following table sets forth the closing price for a Unionamerica ADS
       and a share of MMI Common Stock on the NYSE for the first dealing day
       that the NYSE was open for business in each month from May 1997 to
       October 1997, for June 24, 1997 (being the last trading day prior to the
       announcement that MMI and Unionamerica had entered into the Acquisition
       Agreement), and for October 31, 1997 (being the latest practicable
       trading day prior to the filing of this Prospectus with the Commission):
 
<TABLE>
<CAPTION>
                                                       UNIONAMERICA ADSS    MMI COMMON STOCK
                        DATE                             PRICE ($)(1)         PRICE ($)(1)
- ----------------------------------------------------  -------------------  -------------------
<S>                                                   <C>                  <C>
May 1, 1997.........................................           16.75                21.88
June 2, 1997........................................           16.75                23.00
July 1, 1997........................................           20.75                26.38
August 1, 1997......................................           22.25                27.69
September 2, 1997...................................           20.00                24.75
October 1, 1997.....................................           21.38                26.50
June 24, 1997.......................................           19.50                26.50
October 31, 1997....................................           19.88                24.94
</TABLE>
 
- ------------------------
 
(1) Rounded up to the nearest cent.
 
2.  DIVIDEND POLICY
 
       The policy of the MMI Board is to pay regular quarterly cash dividends.
       The declaration and payment of dividends is subject to the discretion of
       the MMI Board and will depend upon general business conditions, legal and
       contractual restrictions on the payment of dividends and other factors
       that the MMI Board deems relevant.
 
       As an insurance holding company, MMI depends in large part on dividends
       and other payments from its Subsidiaries for the payment of cash
       dividends to MMI stockholders. In the case of MMI's insurance
       Subsidiaries, such payments are restricted by insurance laws, and
       insurance regulators have authority in certain circumstances to prohibit
       payments of dividends and other amounts by MMI's insurance Subsidiaries
       that would otherwise be permitted without regulatory approval. MMI's bank
       credit agreement also restricts the payment of dividends.
 
       As described under "Prospectus Summary--Proposed Refinancing of Bank
       Debt," MMI presently is considering, subject to market conditions, to
       issue in November or December 1997, in a private placement to
       institutional investors, approximately $100 million of preferred trust
       securities, which will not be registered under the Securities Act and may
       not be offered and sold in the U.S. absent registration or an applicable
       exemption from registration requirements. There is no assurance that MMI
       will decide to proceed with such issuance. The offering will be made
       through the issuance of the Refinancing Securities. So long as no event
       of default under the subordinated debentures has occurred and is
       continuing, MMI will have the right to defer payment of interest on the
       subordinated debentures at any time or from time to time for a period not
       exceeding 10 consecutive semi-annual periods for each extension period.
       At the end of any such extension period, MMI will be required to pay all
       accrued and unpaid interest together with additional interest thereon.
       During any such extension period, among other things, MMI may not declare
       or pay any dividends or distributions on, or redeem, purchase, acquire,
       or make a liquidation payment with respect to, any of its capital stock,
       except for dividends or distributions in shares of,
 
                                    APP-D-1
<PAGE>
       or options, warrants or rights to subscribe for or purchase shares of,
       MMI Common Stock. MMI has no present intention to elect to defer payment
       of interest on the subordinated debentures.
 
3.  EXCHANGE RATE INFORMATION
 
       The following table shows, for the periods and dates indicated, certain
       information regarding the exchange rate for pounds sterling, expressed in
       dollars per L1.00:
 
<TABLE>
<CAPTION>
                                                                      DAILY
                                                                     AVERAGE      AVERAGE
          FINANCIAL YEAR ENDED DECEMBER 31            PERIOD END      RATE*       RATE**       HIGH        LOW
- ----------------------------------------------------  -----------  -----------  -----------  ---------  ---------
<S>                                                   <C>          <C>          <C>          <C>        <C>
1992................................................        1.51         1.77         1.76        2.00       1.51
1993................................................        1.48         1.50         1.50        1.59       1.42
1994................................................        1.57         1.53         1.54        1.64       1.46
1995................................................        1.55         1.58         1.58        1.64       1.53
1996................................................        1.71         1.56         1.57        1.71       1.49
</TABLE>
 
- ------------------------
 
*   The daily average of the Noon Buying Rates.
 
**  The average of the Noon Buying Rates on the last day of each month during
    the period.
 
                                    APP-D-2
<PAGE>
                                   APPENDIX E
          CERTAIN ADDITIONAL INFORMATION REQUIRED UNDER THE CITY CODE
 
1.  RESPONSIBILITY
 
    (a) MMI
 
       The Directors of MMI (whose names are set forth in paragraph 2(a) below)
       accept responsibility for the information contained in this Prospectus,
       except for the information in this Prospectus concerning Unionamerica,
       the Directors of Unionamerica and their immediate families, for which the
       Directors of Unionamerica accept responsibility.
 
       Subject as aforesaid, to the best of the knowledge and belief of the
       Directors of MMI (who have taken all reasonable care to ensure that such
       is the case), the information contained in this Prospectus for which they
       are responsible is in accordance with the facts and does not omit
       anything likely to affect the import of such information.
 
    (b) UNIONAMERICA
 
       The Directors of Unionamerica (whose names are set forth in paragraph
       2(b) below) accept responsibility for the information contained in this
       Prospectus relating to Unionamerica and its Subsidiaries, themselves and
       their immediate families. To the best of the knowledge and belief of the
       Directors of Unionamerica (who have taken all reasonable care to ensure
       that such is the case), the information contained in this Prospectus for
       which they are responsible is in accordance with the facts and does not
       omit anything likely to affect the import of such information.
 
       The foregoing statements are included solely to comply with the
       requirements of Rule 19.2 of the City Code and shall not be deemed to
       establish or expand any liability under the Securities Act, under which
       the Directors of MMI may have liability for the Registration Statement,
       or any other U.S. securities laws, beyond that imposed by the Securities
       Act or such other laws, nor shall they be deemed to establish liability
       under the laws of any state of the U.S.
 
2.  DIRECTORS
 
    (a) The Directors of MMI and their respective functions are as follows:
 
        CHAIRMAN, CHIEF EXECUTIVE OFFICER AND DIRECTOR
 
           B. Frederick Becker
 
        DIRECTORS
 
          Richard R. Barr
           George B. Caldwell
           K. James Ehlen
           F. Laird Facey
           William M. Kelley
           Andrew D. Kennedy
           Timothy R. McCormick
           Gerald L. McManis
           Scott S. Parker
           Edward C. Peddie
           Joseph D. Sargent
 
        The business address of all the MMI Directors and the principal head
    office of MMI is 540 Lake Cook Road, Deerfield, Illinois 60015-5290 U.S.A.
 
                                    APP-E-1
<PAGE>
    (b) The Directors of Unionamerica and their respective functions are as
       follows:
 
        EXECUTIVE DIRECTORS
 
          Ian G. Sinclair
           Peter J. Cooper
 
        NON-EXECUTIVE DIRECTORS
 
          Sir Christopher Leaver
           Stanislas M. Yassukovich
 
        INVESTOR DIRECTORS
 
          Steven B. Gruber
           Robert A. Spass
           Paul H. Warren
 
    The business address of all the Unionamerica Directors and the head office
    of Unionamerica is 3 Minster Court, Mincing Lane, London EC3R 7DD, England.
 
3.  DISCLOSURES OF INTERESTS AND DEALINGS
 
    (a) The following persons, all being employees of Unionamerica (Ian G.
       Sinclair and Peter J. Cooper also being Directors of Unionamerica), have
       irrevocably undertaken to accept, or procure the acceptance of, the Offer
       in respect of not less than the following Unionamerica ADSs representing
       3.7% of the issued share capital of Unionamerica as of October 31, 1997.
       The irrevocable Undertakings also provide that the Directors shall accept
       (i) the Offer in respect of the following number of Options upon the
       exercise (if any) of such Options; or (ii) the proposals being made to
       Option holders under the Unionamerica Share Option Schemes in respect of
       such Options.
 
<TABLE>
<CAPTION>
                                                                           UNIONAMERICA ADSS
NAME                                                   UNIONAMERICA ADSS      UNDER OPTION
- -----------------------------------------------------  ------------------  ------------------
<S>                                                    <C>                 <C>
Ian G. Sinclair......................................         120,977             215,930
Peter J. Cooper......................................          52,902             116,926
Hugh B. Jago.........................................          37,200              80,092
Andrew E. Marks......................................          25,476              38,931
Timothy P. Open......................................          15,882              43,853
Hugh C. Evans........................................          15,782              43,853
Howard G. Eyre.......................................          12,750              26,326
Alasdair G. Bishop...................................          11,048              33,743
Anthony B. Withersby.................................           6,313              17,923
Roland J. James......................................           6,250              14,278
Stuart C. Willoughby.................................           3,995              12,867
Trevor R. Smith......................................           2,354               5,711
</TABLE>
 
                                    APP-E-2
<PAGE>
       Irrevocable Undertakings have also been given by the following to accept
       the offer in respect of not less than the following Unionamerica ADSs
       representing 46.6% of the issued share capital of Unionamerica as of
       October 31, 1997.
 
<TABLE>
<CAPTION>
NAME                                                                        UNIONAMERICA ADSS
- --------------------------------------------------------------------------  ------------------
<S>                                                                         <C>
International Insurance Investors, L.P....................................        1,806,920
IIA Management............................................................          133,929
UA Partners, L.P..........................................................        1,147,355
UA Partners II, L.P.......................................................          498,850
Acadia Partners, L.P......................................................          375,000
</TABLE>
 
       All of the irrevocable Undertakings referred to above cease to be binding
       in the event that a third party makes, or publicly announces a firm
       intention to make, a higher competing offer for Unionamerica and MMI does
       not prior to midnight on the tenth business day after the day on which
       such higher competing offer is made or, if earlier, publicly announced,
       announce a revised offer on terms which provide, in the reasonable
       opinion of DLJ, a substantially equivalent or greater consideration than
       the higher competing offer, and a $5,000,000 fee is paid to MMI.
 
    (b) The interests of the Directors of Unionamerica and their immediate
       families, all of which are beneficial, in Unionamerica ADSs as shown on
       October 31, 1997 (the latest practicable date prior to the filing of this
       Prospectus with the Commission), in the register of Unionamerica
       Directors' interests maintained under the provisions of Sections 324 to
       328 of the Companies Act were as follows:
 
<TABLE>
<CAPTION>
                                                                OPTIONS OVER UNIONAMERICA ADSS
                                                                -------------------------------
                                                                                 EXERCISE
                                                                           --------------------
NAME                                        UNIONAMERICA ADSS    NUMBER     PERIOD      PRICE
- ------------------------------------------  ------------------  ---------  ---------  ---------
<S>                                         <C>                 <C>        <C>        <C>
Ian G. Sinclair...........................         120,977        100,840    9/09/03  $    4.48
                                                                  115,090    7/23/06      15.50
Peter J. Cooper...........................          52,902         54,622    9/09/03       4.48
                                                                   62,304    7/23/06      15.50
Robert A. Spass...........................          46,189         --         --         --
Steven B. Gruber..........................          --             --         --         --
Paul H. Warren............................          27,234         --         --         --
Sir Christopher Leaver....................          --             --         --         --
Stanislas M. Yassukovich..................          --             --         --         --
</TABLE>
 
       As at October 31, 1997, none of the Directors of Unionamerica had
       reported any non-beneficial interests (as such term is used under the
       City Code) in the share capital of Unionamerica, other than Stanislas M.
       Yassukovich who had a non-beneficial interest in 2,000 Unionamerica ADSs
       held in a trust for which he serves as the executor.
 
    (c) There have been no dealings for value by current Directors of
       Unionamerica in Unionamerica ADSs during the disclosure period. Philip
       Marcell, a former Director of Unionamerica, sold 67,131 Unionamerica ADSs
       on June 27, 1997.
 
                                    APP-E-3
<PAGE>
    (d) The interests of Directors of MMI and their immediate families, all of
       which are beneficial (save where indicated), in MMI Common Stock as shown
       on October 31, 1997 (the latest practicable trading day prior to the
       filing of this Prospectus with the Commission) were as follows:
 
<TABLE>
<CAPTION>
                                                                            OPTIONS OVER MMI COMMON STOCK
                                                                  -------------------------------------------------
                                                                                              END OF
                                                   MMI COMMON                                EXERCISE
NAME                                                 STOCK        DATE OF GRANT    NUMBER     PERIOD     PRICE ($)
- ----------------------------------------------  ----------------  -------------  ----------  ---------  -----------
<S>                                             <C>               <C>            <C>         <C>        <C>
B. Frederick Becker...........................  100,874.16            06/24/93   106,875     6/23/03         13.50
                                                                      04/21/94   143,000     4/20/04        13.125
                                                                      02/26/97   25,000      2/25/07         29.25
Richard R. Barr...............................  --                    06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04         13.13
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
George B. Caldwell............................  18,557                06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04        13.125
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
K. James Ehlen................................  --                    01/01/97   4,125       12/31/06        32.25
F. Laird Facey................................  24,592                06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04        13.125
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
William M. Kelley.............................  300                   01/07/94   4,125       1/06/04         13.50
                                                                      04/21/94   1,375       4/20/04        13.125
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
Andrew D. Kennedy.............................  459                   04/18/96   4,125       4/17/06         27.75
                                                                      04/17/97   1,375       4/16/07         22.75
Timothy R. McCormick..........................  2,076                 06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04        13.125
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
Gerald L. McManis.............................  189,278.42(1)         02/22/95   5,000       2/21/05         15.50
                                                                      02/28/96   8,000       2/27/06         24.25
                                                                      02/26/97   2,000       2/25/07         22.75
</TABLE>
 
                                    APP-E-4
<PAGE>
<TABLE>
<CAPTION>
                                                                            OPTIONS OVER MMI COMMON STOCK
                                                                  -------------------------------------------------
                                                                                              END OF
                                                   MMI COMMON                                EXERCISE
NAME                                                 STOCK        DATE OF GRANT    NUMBER     PERIOD     PRICE ($)
- ----------------------------------------------  ----------------  -------------  ----------  ---------  -----------
<S>                                             <C>               <C>            <C>         <C>        <C>
Scott S. Parker...............................  --                    06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04         13.13
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
Edward C. Peddie..............................  2,310                 06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04        13.125
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
Joseph D. Sargent.............................  4,420                 06/24/93   4,125       6/23/03         13.50
                                                                      04/21/94   1,375       4/20/04         13.13
                                                                      04/19/95   1,375       4/18/05        18.625
                                                                      04/18/96   1,375       4/17/06         27.44
                                                                      04/17/97   1,375       4/16/07         22.75
</TABLE>
 
(1)  This shareholding includes 3,500 shares held by a closely-held corporation
     to which Gerald L. McManis disclaims beneficial ownership.
 
     Other than as set forth in this Appendix E, as at October 31, 1997, none of
     the Directors of MMI had any non-beneficial interests in the share capital
     of MMI.
 
    (e) There have been no dealings for value by Directors of MMI in MMI Common
       Stock during the disclosure period save as follows:
 
<TABLE>
<CAPTION>
                                                     NUMBER OF
                                                   SHARES OF MMI
                                                       COMMON
DIRECTOR                                               STOCK          PRICE          DATE
- -----------------------------                      --------------  -----------  ---------------
<S>                            <C>                 <C>             <C>          <C>
 
B. Frederick Becker..........  Purchase            100                  30.75          10/18/96
                               Option Grant         25,000              29.25           2/26/97
                               Purchase             1,000              22.625           5/15/97
                               Disposition(1)       50,000                 --            6/5/97
                               Purchase(2)          759.94                 --    as of 12/31/96
                               Disposition(3)       884.49                 --    as of 12/31/96
Richard R. Barr..............  Option Grant        1,375                22.75           4/17/97
                               Issuance(4)          1,105.23               --    as of 10/31/97
George B. Caldwell...........  Purchase            3,000               24.625           3/11/97
                               Option Grant         1,375               22.75           4/17/97
                               Issuance(4)          1,212.52               --    as of 10/31/97
K. James Ehlen...............  Option Grant        4,125                32.25            1/1/97
F. Laird Facey...............  Option Grant        1,375                22.75           4/17/97
                               Purchase             1,000               25.00            3/7/97
                               Purchase             1,000               22.00            5/9/97
</TABLE>
 
                                    APP-E-5
<PAGE>
<TABLE>
<CAPTION>
                                                     NUMBER OF
                                                   SHARES OF MMI
                                                       COMMON
DIRECTOR                                               STOCK          PRICE          DATE
- -----------------------------                      --------------  -----------  ---------------
<S>                            <C>                 <C>             <C>          <C>
William M. Kelley............  Option Grant        1,375                22.75           4/17/97
                               Issuance(4)          547.48                 --    as of 10/31/97
Andrew D. Kennedy............  Purchase            390                 30.875           10/9/96
                               Purchase             36                 31.125          12/17/96
                               Purchase             33                 32.125           1/17/97
                               Option Grant         1,375               22.75           4/17/97
                               Issuance(4)          1,072.08               --    as of 10/31/97
Timothy R. McCormick.........  Option Grant        1,375                22.75           4/17/97
Gerald L. McManis............  Option Grant        2,000                22.75           2/26/97
                               Purchase(2)          12.51                  --    as of 12/31/96
                               Purchase(3)          391.99                 --     as of 12/1/96
Scott S. Parker..............  Option Grant        1,375                22.75           4/17/97
                               Issuance(4)          1,018.43               --    as of 10/31/97
Edward C. Peddie.............  Option Grant        1,375                22.75           4/17/97
                               Issuance(4)          1,212.52               --    as of 10/31/97
Joseph D. Sargent............  Option Grant        1,375                22.75           4/17/97
</TABLE>
 
- ------------------------
 
(1) Non-taxable transfer for estate planning purposes.
 
(2) Aggregate acquisitions of MMI Common Stock during calendar year 1996 under
    MMI's Employee Stock Investment Plan.
 
(3) Aggregate of acquisitions and/or dispositions of MMI Common Stock during
    calendar year 1996 under the MMI Companies, Inc. Savings and Profit Sharing
    Plan (401(k)).
 
(4) Issued in lieu of director's fees for the first three quarters of fiscal
    1997.
 
    (f) Save as otherwise disclosed in this Appendix E:
 
            (i) MMI owns no Unionamerica Securities;
 
            (ii) no Director of MMI or Unionamerica is interested (as defined in
       Parts VI and X of the Companies Act) in relevant securities (as defined
       below);
 
           (iii) no Person acting in concert with MMI or Unionamerica (as
       defined in the City Code) owns or controls any relevant securities;
 
            (iv) no Person who has irrevocably committed himself to accept the
       Offer owns or controls any relevant securities;
 
            (v) Unionamerica owns no shares of MMI Common Stock;
 
            (vi) save as disclosed below, no Subsidiary of Unionamerica, nor any
       pension fund of Unionamerica or of any of its Subsidiaries, nor any bank,
       stockbroker, financial or other professional advisor (excluding exempt
       market-makers) to Unionamerica or its Subsidiaries or any Persons
       controlling, controlled by, or under the same control as, any such bank,
       stockbroker, financial or other professional advisor, owns or controls
       relevant securities; and
 
           (vii) no Person mentioned in subparagraphs (i) to (v) above has dealt
       for value in relevant securities during the disclosure period and no
       Person mentioned in subparagraph (vi) has dealt
 
                                    APP-E-6
<PAGE>
       for value in relevant securities between June 25, 1996 and October 31,
       1997 (the latest practicable trading day prior to the filing of this
       Prospectus with the Commission).
 
    (g) For the purposes of the above:
 
            (i) "relevant securities" include:
 
               (A) Unionamerica Securities;
 
               (B) securities convertible into Unionamerica Securities, rights
           to subscribe for Unionamerica Securities and options for Unionamerica
           Securities;
 
               (C) equity share capital of MMI;
 
               (D) securities of MMI which carry substantially the same rights
           as those to be issued under the Offer;
 
               (E) securities convertible into the securities referred to in
           clauses (C) or (D) above, rights to subscribe for securities referred
           to in clauses (C) or (D) above and options (including traded options)
           in respect of the securities referred to in clauses (C) or (D) above;
           and
 
               (F) derivatives in respect of any of the forgoing.
 
            (ii) "bank" means any bank whose relationship to any relevant party
       is not solely the provision of normal commercial banking services or such
       services in connection with the Offer as handling acceptances and other
       registration work; and
 
           (iii) "disclosure period" means the period commencing on June 25,
       1996 and ending on October 31, 1997 being respectively the date 12 months
       preceding the announcement that MMI and Unionamerica had entered into the
       Acquisition Agreement and the latest practicable trading day prior to the
       filing of this Prospectus with the Commission.
 
            (iv) "derivatives" include any financial product whose value in
       whole or in part is determined directly or indirectly by reference to the
       price of an underlying security but which does not include the
       possibility of delivery of such underlying security.
 
                                    APP-E-7
<PAGE>
    (h) In the ordinary course of business, Smith Barney actively trades the
       equity securities of Unionamerica and MMI for its own account and for the
       accounts of its customers and, accordingly, may at any time hold a long
       or short position in such securities. These dealings are set out below:
 
<TABLE>
<CAPTION>
                                                                      NUMBER OF SHARES OF MMI
TYPE OF DEALING                                                            COMMON STOCK         PRICE ($)    DATE
- -------------------------------------------------------------------  -------------------------  ---------  ---------
<S>                                                                  <C>                        <C>        <C>
Sale...............................................................                  2              28.87  06/26/96
Purchase...........................................................                500              32.37  08/08/96
Sale...............................................................                500              32.62  08/08/96
Purchase...........................................................              5,600              30.75  09/20/96
Sale...............................................................              5,000              31.00  09/20/96
Sale...............................................................              5,600              30.62  09/20/96
Purchase...........................................................              5,000              30.50  09/23/96
Purchase...........................................................                200              30.25  09/25/96
Sale...............................................................                200              30.00  09/26/96
Purchase...........................................................              9,500              30.00  09/26/96
Purchase...........................................................             11,600              30.00  09/26/96
Purchase...........................................................                800              30.00  09/26/96
Purchase...........................................................              6,200              30.00  09/27/96
Sale...............................................................              7,400              30.12  09/27/96
Purchase...........................................................              3,700              30.00  09/30/96
Sale...............................................................             20,600              30.12  09/30/96
Purchase...........................................................                400              30.00  10/01/96
Purchase...........................................................              7,800              29.87  10/01/96
Sale...............................................................              3,800              30.00  10/01/96
Purchase...........................................................             10,000              29.87  10/02/96
Sale...............................................................              8,200              30.25  10/02/96
Sale...............................................................              7,000              30.25  10/02/96
Sale...............................................................              3,000              30.25  10/03/96
Sale...............................................................                  1              30.63  10/10/96
Sale...............................................................                  1              30.12  11/07/96
Purchase...........................................................                200              29.25  11/08/96
Sale...............................................................                500              30.62  11/25/96
Purchase...........................................................                500              30.12  11/26/96
Purchase...........................................................                  3              23.62  03/14/97
Sale...............................................................                  3              23.12  03/14/97
</TABLE>
 
    (i) Wellington Management Company, LLP has a beneficial interest in
       1,185,940 shares of MMI Common Stock, representing 10.10% of the issued
       share capital of MMI.
 
4.  SERVICE CONTRACTS OF UNIONAMERICA DIRECTORS
 
    (a) Details of the service contracts of Unionamerica Executive Directors
       with Unionamerica are as follows:
 
        UA Management Company, a Subsidiary of Unionamerica which manages the
    operations of Unionamerica, has entered into a separate service contract
    (each, a "Service Contract" and collectively, the "Service Contracts") with
    each of Peter J. Cooper and Ian G. Sinclair, pursuant to which Mr. Cooper is
    employed as Managing Director--Finance and Administration and Mr. Sinclair
    as Chief Executive Officer. UA Management Company has agreed to employ each
    of Mr. Cooper and Mr. Sinclair until the earlier to occur (i) of the
    termination of his employment by UA Management Company upon not less than
    three months' written notice or (ii) the day upon which he attains the age
    of 65 years or such other age as may be determined by the Unionamerica Board
    as his retirement age.
 
                                    APP-E-8
<PAGE>
        The base salaries of Messrs. Cooper and Sinclair for the years ended
    March 31, 1997 and March 31, 1998 are set forth in the table below. Messrs.
    Cooper and Sinclair are also entitled to participate in Unionamerica's
    pension, health insurance, profit sharing and incentive plans from time to
    time, to be reimbursed for out of pocket expenses incurred in the course of
    their employment, and to receive the use of company automobiles. Bonuses
    paid to Messrs. Cooper and Sinclair under Unionamerica's profit sharing and
    incentive plans for the year ended March 31, 1997 are set forth in the table
    below.
 
        Each of Mr. Cooper and Mr. Sinclair can terminate his employment upon
    not less than two months' written notice to UA Management Company. UA
    Management Company can terminate his employment at any time with or without
    cause. If UA Management Company terminates his employment with cause, he is
    entitled to receive only accrued but unpaid salary as of the date of
    termination. If UA Management Company terminates his employment without
    cause, he is entitled to receive a payment in lieu of salary and other
    benefits for three months. In addition, each of Mr. Sinclair and Mr. Cooper
    has agreed (i) for the period of six months after termination of his
    employment, not to entice certain employees of Unionamerica away from
    Unionamerica and not to solicit certain clients of Unionamerica and (ii) for
    the period of four months after termination of employment, not to engage in
    any competing business in the London market.
 
<TABLE>
<CAPTION>
                                                               PRESENT       PREVIOUS
                                                               ANNUAL         ANNUAL        BONUS FOR
                                                            REMUNERATION   REMUNERATION    FISCAL 1996
                                                              (YEAR TO       (YEAR TO       (YEAR TO
                                                 DATE OF      MARCH 31,      MARCH 31,      MARCH 31,
DIRECTOR                                        CONTRACT        1998)          1997)          1997)
- ---------------------------------------------  -----------  -------------  -------------  -------------
<S>                                            <C>          <C>            <C>            <C>
Peter J. Cooper..............................    09/10/93      L119,300       L114,700       L172,970
Ian G. Sinclair..............................    09/10/93      L257,920       L248,000       L298,600
</TABLE>
 
    (b) The non-Executive Directors, Sir Christopher Leaver and Stanislas
       Yassukovich, have no special arrangements with Unionamerica.
 
    (c) Peter J. Cooper and Ian G. Sinclair, in common with all other employees
       of Unionamerica, are employed by UA Management Company, a wholly-owned
       subsidiary of Unionamerica. No Director of Unionamerica has any other
       service contract or other arrangement with any Subsidiary of
       Unionamerica.
 
    (d) Save as disclosed above or in paragraph (e) below, there are no
       contracts of service between any Director of Unionamerica and
       Unionamerica or any of its Subsidiaries having more than 12 months to
       run, and no such contract has been entered into or amended or replaced
       within the six months preceding the date of this Prospectus.
 
    (e) The current Non-Executive Directors of Unionamerica (Stanislas
       Yassukovich and Sir Christopher Leaver) intend to resign their
       directorships as soon as practicable following successful completion of
       the Offer. In addition, the Investor Directors (Robert A. Spass and Paul
       H. Warren) will upon completion of the Offer cease automatically to be
       directors of Unionamerica as a result of the operation of the provisions
       of Article 87 of the Unionamerica Articles, and Steven B. Gruber intends
       to resign his directorship as soon as practicable following successful
       completion of the Offer.
 
5.  MANAGEMENT AND EMPLOYEES
 
    It is MMI's present intention to continue the existing management and
business plans of Unionamerica after the Proposed Acquisition, and to continue
to operate Unionamerica as a distinct business entity at its present location in
London. MMI intends to honor the laws of the U.K. with respect to employment
rights.
 
                                    APP-E-9
<PAGE>
6.  MATERIAL CONTRACTS
 
    (a) The following contracts (not being contracts entered into in the
       ordinary course of business) have been entered into by Unionamerica or
       its Subsidiaries within the two years immediately preceding June 25,
       1997, and since June 25, 1997, up to the date hereof and are or may be
       material:
 
            (i) The Acquisition Agreement.
 
            (ii) Agreement for the sale and purchase of shares in JMA Holdings
       Limited ("JMAHL") dated July 23, 1997, between various individuals named
       in the Agreement, UA Combined Investment Company Limited ("UACIC"') and
       Unionamerica Acquisition Company Limited ("UAC")(the "Share Purchase
       Agreement."). UACIC is a joint venture vehicle of which 80% of its share
       capital (conferring 80% of the economic interest and 67% of the voting
       rights) is owned by UAC and 20% of its share capital (representing 20% of
       the economic interest and 33% of the voting rights) is owned by Aon
       Specialty Group Limited, a subsidiary of Aon Holdings Limited, itself a
       subsidiary of Aon Corporation, a Delaware corporation. UACIC has agreed
       to acquire 49% of the economic interest and 33% of the voting interest in
       JMAHL. UAC has also agreed to acquire 16% of the voting interest in
       JMAHL. JMAHL is the holding company of Jago Managing Agency Limited
       ("JMAL"), a Lloyd's managing agency. The consideration was L6,250,000 of
       which L3,789,945 was paid in cash; L1,060,055 by the issue of Series "A"
       Loan Notes and L1,400,000 by the issue of Series "B" Loan Notes issued by
       UACIC.
 
           (iii) Shareholders and Subscription Agreement dated July 23, 1997,
       between UACIC, Aon Specialty Group Limited and UAC which contains
       provisions regulating their participation in UACIC.
 
            (iv) Shareholders' Agreement dated July 23, 1997, between UACIC,
       Jago Group Limited, the shareholders of Jago Group Limited and JMAHL
       which contains provisions regulating their participation in JMAHL.
 
            (v) Shareholders Agreement dated July 23, 1997, between UACIC, Jago
       Holdings Limited and the various individuals listed in the agreement
       which contains provisions regulating their participation in Jago
       Dedicated Limited.
 
            (vi) Loan Agreement dated April 29, 1997, between UAC as borrower,
       (1) UA Management Company as original guarantor, (2) Chase Investment
       Bank Limited as arranger, (3) the financial institutions named therein as
       banks, (4) Chase Manhattan International Limited as facility agent (5)
       and as security agent (6) pursuant to which the banks agreed to make
       available to the borrower a term loan facility in the principal amount of
       US$35,000,000 in one drawdown to refinance existing bank facilities and a
       revolving loan of up to US$20,000,000 for general standby financing
       requirements. The revolving facility may be drawn in minimum amounts of
       US$5,000,000 and integral multiples of US$1,000,000. The margin payable
       in respect of each facility is 9/16ths per annum and the borrower pays a
       commitment of 28 basis points per annum on the undrawn amount of the
       revolving facility from time to time. The borrower paid an arrangement
       fee of US$350,000 in respect of the facilities and pays an annual agency
       fee to the facility agent of US$15,000. The facilities are secured by a
       guarantee from UA Management Company of the borrower's obligations under
       the Loan Agreement and by debentures executed by each of the borrower and
       the original guarantor in favor of the security agent on behalf of the
       banks creating fixed and floating charges over their respective assets.
       The facilities are subject to representations, covenants (including
       financial condition covenants) and events of default usual in the market
       for facilities of this nature.
 
           (vii) On December 31, 1996, UAC acquired a 51% shareholding in Jago
       Dedicated Limited. UAC paid L1,119,909 for such shares.
 
                                    APP-E-10
<PAGE>
          (viii) Subscription and Shareholders Agreement dated July 16, 1996,
       between Unionamerica Holdings plc and Minova Enterprises Limited. The
       agreement governs the joint venture between the two parties in relation
       to each party's 50% interest in Polis UK Direct Limited which in turn
       holds shares in Polis Direct B.V., a company registered in the
       Netherlands. The agreement determines the terms under which the business
       of Polis UK is conducted and which imposes certain joint restrictions and
       obligations on Unionamerica and Minova.
 
            (ix) Underwriting Agreement between Unionamerica, DLJ, Merrill Lynch
       & Co., Merrill Lynch, Pierce, Fenner & Smith Incorporated and other
       underwriters named in the Agreement ("Underwriters") dated December 5,
       1995, whereby Unionamerica agreed to issue and sell to the Underwriters a
       specified number of Unionamerica ADSs to be represented by American
       Depository Receipts ("ADRs"') on the basis that the Underwriters would
       undertake an initial public offering of those shares. The price was
       $15.84 per ADS. The Agreement contained various warranties and
       indemnities given by Unionamerica and the Underwriters.
 
            (x) A Deposit Agreement dated December 1, 1995, between
       Unionamerica, Morgan Guaranty Trust Company of New York, as depository
       and the owners from time to time of ADRs issued pursuant to the terms of
       the Agreement. The Agreement governs the terms and conditions under which
       ADSs are deposited and ADRs are issued by the depository.
 
            (xi) Shareholders Agreement dated December 4, 1995, between
       Unionamerica, International Insurance Advisers, Inc. ("IIA") and other
       individuals named in the Agreement. The Agreement replaced an earlier
       Shareholders Agreement and contains certain restrictions on the transfer
       of Unionamerica Securities by the parties thereto, as well as certain
       voting agreement provisions.
 
    (b) The following contracts (not being entered into in the ordinary course
       of business) have been entered into by MMI within the two years prior to
       execution of the Acquisition Agreement and are or may be material:
 
            (i) Rights Agreement dated as of June 14, 1997 by and between the
       Registrant and ChaseMellon Shareholder Services L.L.C., as Rights Agent.
 
            (ii) Amended and Restated Credit Agreement dated as of January 18,
       1996 among the Registrant, Various Lenders and Bank of America National
       Trust and Savings Association, as Agent for the Lenders.
 
           (iii) Waiver of Right to Elect Director dated October 21, 1996,
       between the Registrant and each of Conning Insurance Capital Limited
       Partnership, Conning Insurance Capital International Partnership, Conning
       Insurance Capital Limited Partnership II and Conning Insurance Capital
       International Partnership II.
 
            (iv) Third Amendment to Lease, effective February 1, 1996 between
       the Registrant and MATAS Corporation.
 
            (v) Fourth and Fifth Amendments to Lease, effective July 1996
       between the Registrant and MATAS Corporation.
 
            (vi) Sixth Amendment to Lease, effective as of the 1st day of March,
       1997 between the Registrant and American National Bank and Trust Company
       of Chicago, not individually, but solely as Trustee under a certain Trust
       Agreement dated the 30th day of July, 1985, and known as Trust Number
       65110.
 
           (vii) Seventh Amendment to Lease, effective as of the 12th day of
       June, 1997 between the Registrant and MATAS Corporation.
 
                                    APP-E-11
<PAGE>
7.  THE COMPULSORY ACQUISITION
 
    If, on or before, March 6, 1998 as a result of the Offer or otherwise, MMI
    acquires or contracts to acquire shares of Unionamerica Common Stock
    (including those represented by Unionamerica ADSs) representing at least 90%
    of the outstanding Unionamerica ADSs to which the Offer relates, then (i)
    MMI will be entitled and intends to effect a compulsory acquisition to
    compel the purchase of the remainder of the outstanding Unionamerica Common
    Stock (including those represented by Unionamerica ADSs) on the same terms
    as those offered in the Offer in accordance with Sections 428 to 430F of the
    Companies Act; and/or (ii) a holder of Unionamerica Common Stock (including
    those represented by Unionamerica ADSs) may require MMI to purchase his
    Unionamerica Common Stock (including those represented by Unionamerica ADSs)
    on the same terms as those offered in the Offer in accordance with Sections
    430A and 430B of the Companies Act. See Appendix F to this Prospectus--
    "Certain Provisions of the Companies Act".
 
8.  CERTAIN LEGAL AND REGULATORY MATTERS
 
    Except as set out herein, and other than in compliance with the Panel's
    requirements in relation to the City Code and with U.S. securities laws, MMI
    is not aware of (i) any license or regulatory permit that appears to be
    material to the business of Unionamerica and its Subsidiaries taken as a
    whole which might be adversely affected by MMI's acquisition of Unionamerica
    as contemplated herein or (ii) any approval or other action by any domestic
    or foreign governmental, administrative or regulatory agency or authority
    that appears to be material to Unionamerica and its Subsidiaries taken as a
    whole and required for the acquisition or ownership of Unionamerica ADSs by
    MMI as contemplated herein. Should any such approval or other action be
    required, MMI currently contemplates that such approval or other action will
    be sought. There can be no assurance that any such approval or other action,
    if needed, would be obtained or would be obtained without substantial
    conditions attached thereto or that failure to obtain any such approval or
    other action might not result in consequences adverse to the business of
    Unionamerica.
 
    U.K. ANTITRUST LAWS. The Offer will lapse if it is referred to the MMC
    before 12 midnight, New York City time, on the Expiration Date, including
    any extension thereof, or prior to the date on which the Offer becomes
    unconditional in all respects, whichever is the later. In such a case, the
    Offer shall cease to be capable of acceptance and MMI and Unionamerica
    Securityholders shall cease to be bound by prior tenders.
 
    U.S. ANTITRUST LAWS. On September 15, 1997, the Federal Trade Commission
    granted the request of MMI for early termination of the waiting period under
    the HSR Act.
 
    U.K. INSURANCE LAWS
 
    U.K. DEPARTMENT OF TRADE AND INDUSTRY
 
    One of Unionamerica's Subsidiaries, Unionamerica Insurance Company Limited,
    is a U.K. authorized insurance company. In the U.K. the DTI is responsible
    for the authorization and for the ongoing supervision of U.K. insurance
    companies and under U.K. law consent is required from the DTI prior to any
    Person becoming a controller (as defined in the Insurance Companies Act
    1982) of such a company. The definition of controller will include MMI, any
    managing directors of MMI and any Persons holding an interest of more than
    ten percent in MMI. The Offer is conditional upon the obtaining of DTI
    consent to the proposed new controllers on terms acceptable to MMI. MMI
    applied for such consents on July 28, 1997, and on September 12, 1997, the
    DTI advised MMI that it had no objection to the proposed new controllers
    becoming controllers of Unionamerica.
 
                                    APP-E-12
<PAGE>
    LLOYD'S OF LONDON
 
    Unionamerica also holds an interest through its Subsidiaries in a corporate
    capital vehicle at Lloyd's, Jago Capital Limited ("Jago Capital"). The
    consent of Lloyd's is required to any Person becoming a controller of a
    Lloyd's corporate member, which will include MMI and any other Person who
    will hold 10% or more of the economic or voting rights in the corporate
    member whether directly or indirectly. Again, the Offer is conditional on
    these being obtained on terms acceptable to MMI. MMI applied for the
    necessary consents on August 27, 1997, and on September 19, 1997, Lloyd's
    advised MMI that it had no objection to the proposed new controllers of
    Unionamerica becoming controllers of Jago Capital.
 
    Unionamerica also holds, through its Subsidiaries, an effective equity
    interest of approximately 39% in Jago Managing Agency Limited ("Jago
    Managing Agency"), a Lloyd's managing agency. The consent of Lloyd's is also
    required to a Person becoming a controller of a managing agency. A
    controller in this context means a Person who has a voting or economic
    interest equal to or greater than 10% in the managing agency whether held
    directly or indirectly. The Offer is therefore conditional on the obtaining
    of these consents from Lloyd's on terms acceptable to MMI. Once again, MMI
    applied for the necessary consents on September 26, 1997, and on October 29,
    1997, Lloyd's advised MMI that it had no objection to MMI becoming a
    controller of Jago Managing Agency.
 
    U.S. INSURANCE LAWS.
 
    MMI's insurance Subsidiaries (ACIC, HPIC and ACLIC), are subject to
    supervision and regulation of their businesses and financial condition by
    the jurisdictions in which they transact business. Such supervision and
    regulation generally derives from statutes which delegate broad regulatory,
    supervisory and administrative authority to insurance departments and other
    governmental entities.
 
    In addition to state-imposed insurance laws and regulations, MMI is subject
    to statutory accounting practices and the reporting format of the NAIC. The
    NAIC and many states have adopted risk-based capital formulas to establish
    minimum capital and surplus requirements for insurance companies and a model
    act for regulation of such companies. The risk-based capital formula
    measures a company's asset risk, insurance risk, interest rate risk and
    business risk. As of December 31, 1996, the surplus of each of MMI's U.S.
    insurance Subsidiaries exceeded the minimum requirements under the NAIC
    formula.
 
    It is the intention of MMI to comply with all insurance regulations imposed
    on it and its insurance Subsidiaries as a result of the Proposed
    Acquisition.
 
    U.S. STATE TAKEOVER LAWS
 
    A number of states of the U.S. have adopted takeover laws and regulations
    which purport, in varying degrees, to be applicable to attempts to acquire
    securities of corporations which have substantial assets, security holders,
    principal executive offices or principal places of business in such states.
    MMI believes that no state takeover statutes apply to the Offer and MMI has
    not attempted to comply with any state takeover statutes in connection with
    the Offer.
 
    U.S. STATE BLUE SKY LAWS
 
    The Offer is being made to all Unionamerica Securityholders provided,
    however, that Unionamerica Securityholders in any jurisdiction in the U.S.
    in which the making of the Offer or the acceptance thereof would not be in
    compliance with the laws of such jurisdiction should not accept or purport
    to accept the Offer. MMI is not presently aware of any jurisdiction in the
    U.S. that prohibits the making of the Offer. MMI will take all necessary or
    appropriate action for the purpose of making the Offer available to all
    Unionamerica Securityholders. In any jurisdiction the securities laws or
    blue sky laws of which require the Offer to be made by a registered broker
    or dealer, the Offer is being made on
 
                                    APP-E-13
<PAGE>
    behalf of MMI by one or more registered broker or dealers that are licensed
    under the laws of such jurisdiction.
 
9.  EXPERTS
 
    The consolidated financial statements and schedules of MMI Companies, Inc.
    and Subsidiaries at December 31, 1996 and 1995, and for each of the three
    years in the period ended December 31, 1996, incorporated by reference in
    this Prospectus and Registration Statement, have been audited by Ernst &
    Young LLP, independent auditors, as set forth in their reports thereon
    incorporated by reference herein. Such consolidated financial statements are
    incorporated herein by reference in reliance upon such reports given upon
    the authority of such firm as experts in accounting and auditing.
 
    The consolidated financial statements and schedules of Unionamerica Holdings
    plc and Subsidiaries at December 31, 1996, and for the year ended December
    31, 1996, incorporated by reference in this Prospectus and Registration
    Statement have been audited by KPMG Audit Plc, Chartered Accountants and
    Registered Auditors, as set forth in their reports thereon. The consolidated
    financial statements and schedules of Unionamerica Holdings plc and
    Subsidiaries at December 31, 1995, and for each of the two years in the
    period ended December 31, 1995, incorporated by reference in this Prospectus
    and Registration Statement have been audited by KPMG, Chartered Accountants
    and Registered Auditors, as set forth in their reports thereon. Such
    consolidated financial statements are included in reliance upon such reports
    given upon the authority of such firm as experts in accounting and auditing.
 
10. GENERAL
 
    (a) KPMG Audit Plc, KPMG and Ernst & Young LLP have given and not withdrawn
       their written consents to the inclusion of their respective reports.
       Wildman, Harrold, Allen & Dixon, Paul, Weiss, Rifkind, Wharton & Garrison
       and Lovell White Durrant have given and have not withdrawn their consent
       to the inclusion of their respective opinions, and DLJ has given and not
       withdrawn its consent to the inclusion of its recommendations and
       opinion, each in the form and context in which they are included. Smith
       Barney has given and not withdrawn its written consent to the issuance of
       this Prospectus with the references to its name, and has not withdrawn
       its consent to the inclusion of its opinion, in the form and context in
       which it is included.
 
    (b) Except as disclosed in this Appendix E, no agreement, arrangement or
       understanding (including any compensation arrangements) exists between
       MMI or any party acting in concert with MMI for the purposes of the Offer
       and any of the Directors or recent Directors, Unionamerica
       Securityholders or recent stockholders of Unionamerica, having any
       connection with or dependence on the Offer.
 
    (c) There is no agreement, arrangement or understanding whereby the
       beneficial ownership of any of the Unionamerica Securities to be acquired
       by MMI pursuant to the Offer will be transferred to any other Person,
       except that MMI reserves the right to transfer any Unionamerica
       Securities to any of its Subsidiaries.
 
    (d) Save as disclosed in paragraph 3(a) above, neither MMI nor any Person
       acting in concert with MMI nor Unionamerica nor any associate (as defined
       in the City Code) of Unionamerica has any arrangement (including
       indemnity or option arrangement, agreement or understanding (formal or
       informal)) of whatever nature relating to relevant securities (as defined
       in paragraph 3(g) above), which may be an inducement to deal or refrain
       from dealing.
 
       In this subparagraph (d):
 
            (i) references to an "associate" are to:
 
               (A) Subsidiaries and associated companies of MMI and Unionamerica
           respectively and companies of which any such Subsidiaries or
           associated companies are associated companies;
 
                                    APP-E-14
<PAGE>
               (B) banks, financial and other professional advisors (including
           stockbrokers) to MMI and Unionamerica respectively or a company
           covered in clause (A) above, including Persons controlling,
           controlled by or under the same control as such banks, financial or
           other professional advisors;
 
               (C) the Directors (together with their close relatives and
           related trusts) of MMI or Unionamerica respectively or a company
           covered in clause (A) above; and
 
               (D) the pension funds of MMI or Unionamerica respectively or a
           company covered in clause (A) above;
 
            (ii) references to a "bank" do not apply to a bank whose sole
       relationship with MMI or Unionamerica respectively or a company covered
       in clause (A) above is the provision of normal commercial banking
       services or such activities in connection with the Offer as handling
       acceptances and other registration work; and
 
           (iii) ownership or control of 20% or more of the equity share capital
       of a company is regarded as the test of associated status and "control"
       means a holding, or aggregate holdings, of shares carrying 30% or more of
       the voting rights attributable to the share capital of a company which
       are currently exercisable at a general meeting, irrespective of whether
       the holding or aggregate holding gives DE FACTO control.
 
    (e) No proposal exists in connection with the Offer that any payment or
       other benefit shall be made or given to any Director of Unionamerica as
       compensation for loss of office or as consideration for or in connection
       with his retirement from office.
 
    (f) The total emoluments receivable by the Directors of MMI will not be
       varied as a result of the Proposed Acquisition or by any other associated
       transactions.
 
    (g) (i)  So far as the directors of MMI are aware, and save as disclosed in
       this Prospectus, there have been no material changes in the financial or
       trading position of MMI since December 31, 1996; and
 
       (ii)  So far as the Directors of Unionamerica are aware, and save as
       disclosed in this Prospectus, there have been no material changes in the
       financial or trading position of Unionamerica since December 31, 1996.
 
    (h) Smith Barney Europe, Ltd., which is regulated in the U.K. by The
       Securities and Futures Authority Limited, has approved the contents of
       this Prospectus solely for the purposes of Section 57 of the Financial
       Services Act 1986.
 
    (i) DLJ, which is regulated in the U.K. by The Securities and Futures
       Authority Limited, is acting on behalf of Unionamerica and no one else in
       connection with the matters described herein and will not be responsible
       to anyone other than Unionamerica for providing the protections afforded
       to customers of DLJ or for providing advice in relation to the matters
       described herein.
 
11. AVAILABILITY OF CERTAIN DOCUMENTS
 
    MMI and Unionamerica are subject to the informational requirements of the
    Exchange Act, and in accordance therewith, file annual and quarterly
    reports, proxy statements (in the case of MMI) and other information with
    the Commission. Such reports, proxy statements, other information and the
    Registration Statement, including all exhibits thereto and all exhibits to
    prior registration statements filed by MMI and Unionamerica (including the
    service contracts and the material contracts referred to in paragraph 6 of
    this Appendix E) may be inspected without charge and copied at the public
    reference facilities of the Commission at its principal office at Judiciary
    Plaza, 450 Fifth Street, N.W., Room 1024, Washington DC 20549, and at its
    regional offices at Citicorp Center, 500 West Madison Street, Suite 1400,
    Chicago, Illinois 60661 and at Seven World Trade Center, 13th Floor, New
    York, NY 10048. Any interested party may obtain copies of all or any portion
    of the Registration Statement
 
                                    APP-E-15
<PAGE>
    and its exhibits at prescribed rates from the Public Reference Section of
    the Commission at its principal office at Judiciary Plaza, 450 Fifth Street
    N.W., Room 1024, Washington DC, 20549. In addition, reports, proxy
    statements, other information, this Registration Statement and prior
    registration statements of MMI and Unionamerica may be inspected at the
    offices of the New York Stock Exchange Inc., 20 Broad Street, New York, NY
    10005. The Commission maintains a World Wide Web site on the Internet at
    http://www.sec.gov that contains reports, proxy and information statements
    and other information regarding registrants, such as MMI, that file
    electronically with the Commission.
 
                                    APP-E-16
<PAGE>
                                   APPENDIX F
                  CERTAIN PROVISIONS OF THE COMPANIES ACT 1985
                                   PART XIIIA
                                TAKEOVER OFFERS
 
<TABLE>
<S>        <C>
428.       TAKEOVER OFFERS
 
(1)        In this Part of this Act "a takeover offer" means an offer to acquire all the
           shares, or all the shares of any class or classes, in a company (other than shares
           which at the date of the offer are already held by the offeror), being an offer on
           terms which are the same in relation to all the shares to which the offer relates
           or, where those shares include shares of different classes, in relation to all the
           shares of each class.
 
(2)        In subsection (1) "shares" means shares which have been allotted on the date of the
           offer but a takeover offer may include among the shares to which it relates all or
           any shares that are subsequently allotted before a date specified in or determined
           in accordance with the terms of the offer.
 
(3)        The terms offered in relation to any shares shall for the purposes of this section
           be treated as being the same in relation to all the shares or, as the case may be,
           all the shares of a class to which the offer relates notwithstanding any variation
           permitted by subsection (4).
 
(4)        A variation is permitted by this subsection where:
 
           (a)  the law of a country or territory outside the United Kingdom precludes an
           offer of consideration in the form or any of the forms specified in the terms in
                question or precludes it except after compliance by the offeror with
                conditions with which he is unable to comply or which he regards as unduly
                onerous; and
 
           (b)  the variation is such that the persons to whom an offer of consideration in
           that form is precluded are able to receive consideration otherwise than in that
                form but of substantially equivalent value.
 
(5)        The reference in subsection (1) to shares already held by the offeror includes a
           reference to shares which he has contracted to acquire but that shall not be
           construed as including shares which are the subject of a contract binding the
           holder to accept the offer when it made, being a contract entered into by the
           holder either for no consideration and under seal or for no consideration other
           than a promise by the offeror to make the offer.
 
(6)        In the application of subsection (5) to Scotland, the words "and under seal" shall
           be omitted.
 
(7)        Where the terms of an offer make provision for their revision and for acceptance on
           the previous terms to be treated as acceptances on the revised terms, the revision
           shall not be regarded for the purposes of this Part of this Act as the making of a
           fresh offer and references in this Part of this act to the date of the offer shall
           accordingly be construed as references to the date on which the original offer was
           made.
 
(8)        In this Part of this Act "the offeror" means, subject to section 430D, the person
           making a takeover offer and "the company" means the company whose shares are the
           subject of the offer.
 
429.       RIGHT OF OFFEROR TO BUY OUT MINORITY SHAREHOLDERS
 
(1)        If, in a case in which a takeover offer does not relate to shares of different
           classes, the offeror has by virtue of acceptance of the offer acquired or
           contracted to acquire not less than nine-tenths in value of the shares to which the
           offer relates he may give notice to the holder of any
</TABLE>
 
                                    APP-F-1
<PAGE>
<TABLE>
<S>        <C>
           shares to which the offer relates which the offeror has not acquired or contracted
           to acquire that he desires to acquire those shares.
 
(2)        If, in a case in which a takeover offer relates to shares of different classes, the
           offeror has by virtue of acceptances of the offer acquired or contracted to acquire
           not less than nine-tenths in value of the shares of any class to which the offer
           relates, he may give notice to the holder of any shares of that class which the
           offeror has not acquired or contracted to acquire that he desires to acquire those
           shares.
 
(3)        No notice shall be given under subsection (1) or (2) unless the offeror has
           acquired or contracted to acquire the shares necessary to satisfy the minimum
           specified in that subsection before the end of the period of four months beginning
           with the date of the offer; and no such notice shall be given after the end of the
           period of two months beginning with the date on which he has acquired or contracted
           to acquire shares which satisfy that minimum.
 
(4)        Any notice under this section shall be given in the prescribed manner, and when the
           offeror gives the first notice in relation to an offer he shall send a copy of it
           to the company together with a statutory declaration by him in the prescribed form
           stating that the conditions for the giving of the notice are satisfied.
 
(5)        Where the offeror is a company (whether or not a company within the meaning of this
           Act) the statutory declaration shall be signed by a director.
 
(6)        Any person who fails to send a copy of a notice or statutory declaration as
           required by subsection (4) or makes such a declaration for the purposes of that
           subsection knowing it to be false or without having reasonable grounds for
           believing it to be true shall be liable to imprisonment or a fine, or both, and for
           continued failure to send the copy of declaration, to a daily default fine.
 
(7)        If any person is charged with an offence for failing to send a copy of a notice as
           required by subsection (4) it is a defence for him to prove that he took reasonable
           steps for securing compliance with that subsection.
 
(8)        When during the period within which a takeover offer can be accepted the offeror
           acquires or contracts to acquire any of the shares to which the offer relates but
           otherwise than by virtue of acceptance of the offer, then, if:
 
           (a)  the value of the consideration for which they are acquired or contracted to be
           acquired ("the acquisition consideration") does not at that time exceed the value
                of the consideration specified in the terms of the offer; or
 
           (b)  those terms are subsequently revised so that when the revision is announced
           the value of the acquisition consideration, at the time mentioned in paragraph (a)
                above, no longer exceeds the value of the consideration specified in those
                terms,
 
           the offeror shall be treated for the purposes of this section as having acquired or
           contracted to acquire those shares by virtue of acceptances of the offer; but in
           any other case those shares shall be treated as excluded from those to which the
           offer relates.
 
430.       EFFECT OF NOTICE UNDER SECTION 429
 
(1)        The following provisions shall, subject to section 430C, have effect where a notice
           is given in respect to any shares under section 429.
 
(2)        The offeror shall be entitled and bound to acquire those shares on the terms of the
           offer.
 
(3)        Where the terms of an offer are such as to give the holder of any shares a choice
           of consideration the notice shall give particulars of the choice and state:
</TABLE>
 
                                    APP-F-2
<PAGE>
<TABLE>
<S>        <C>
           (a)  that the holder of the shares may within six weeks from the date of the notice
           indicate his choice by a written communication sent to the offeror at an address
                specified in the notice; and
 
           (b)  which consideration specified in the offer is to be taken as applying in
           default of his indicating a choice as aforesaid;
 
           and the terms of the offer mentioned in subsection (2) shall be determined
           accordingly.
 
(4)        Subsection (3) applies whether or not any time limit or the other conditions
           applicable to the choice under the terms of the offer can still be complied with,
           and if the consideration chosen by the holders of the shares:
 
           (a)  is not cash and the offeror is no longer able to provide it; or
 
           (b)  was to have been provided by a third party who is no longer bound or able to
           provide it, the consideration shall be taken to consist of an amount of cash
                payable by the offeror which at the date of the notice is equivalent to the
                chosen consideration.
 
(5)        At the end of six weeks from the date of the notice the offeror shall forthwith:
 
           (a)  send a copy of the notice to the company; and
 
           (b)  pay or transfer to the company the consideration for the shares to which the
                notice relates.
 
(6)        If the shares to which the notice relates are registered, the copy of the notice
           sent to the company under subsection (5)(a) shall be accompanied by an instrument
           of transfer executed on behalf of the shareholder by a person appointed by the
           offeror; and on receipt of that instrument the company shall register the offeror
           as the holder of those shares.
 
(7)        If the shares to which the notice relates are transferable by the delivery of
           warrants or other instruments the copy of the notice sent to the company under
           subsection (5)(a) shall be accompanied by a statement to that effect; and the
           company shall on receipt of the statement issue the offeror with warrants or other
           instruments in respect of the shares and those already in issue in respect of the
           shares shall become void.
 
(8)        Where the consideration referred to in paragraph (b) of subsection (5) consists of
           shares or securities to be allotted by the offeror the reference in that paragraph
           to the transfer of the consideration shall be construed as a reference to the
           allotment of the shares or securities to the company.
 
(9)        Any sum received by a company under paragraph (b) of subsection (5) and any other
           consideration received under that paragraph shall be held by the company on trust
           for the person entitled to the shares in respect of which the sum or other
           consideration was received.
 
(10)       Any sum received by a company under paragraph (b) of subsection (5), and any
           dividend or other sum accruing from any other consideration received by a company
           under that paragraph, shall be paid into a separate bank account, being an account
           the balance on which bears interest an appropriate rate and can be withdrawn by
           such notice (if any) as is appropriate.
 
(11)       Where after reasonable enquiry made at such intervals as are reasonable the person
           entitled to any consideration held on trust by virtue of subsection (9) cannot be
           found and twelve years have elapsed since the consideration was received or the
           company is wound up the consideration (together with any interest, dividend or
           other benefit that has accrued from it) shall be paid into court.
 
(12)       In relation to a company registered in Scotland, subsections (13) and (14) shall
           apply in place of subsection (11).
</TABLE>
 
                                    APP-F-3
<PAGE>
<TABLE>
<S>        <C>
(13)       Where after reasonable inquiry made at such intervals as are reasonable the person
           entitled to any consideration held on trust by virtue of subsection (9) cannot be
           found and twelve years have elapsed since the consideration was received or the
           company is wound up:
 
           (a)  the trust shall terminate;
 
           (b)  the company or, as the case may be, the liquidator shall sell any
           consideration other than cash and any benefit other than cash that has accrued from
                the consideration; and
 
           (c)  a sum representing:
 
                (i)  the consideration so far as it is cash;
 
                (ii)  the proceeds of any sale under paragraph (b) above; and
 
               (iii)  any interest, dividend or other benefit that has accrued from the
                          consideration,
 
           shall be deposited in the name of the Accountant of Court in a bank account such as
           is referred to in subsection (10) and the receipt for the deposit shall be
           transmitted to the Accountant of Court.
 
(14)       Section 58 of the Bankruptcy (Scotland) Act 1985 (so far as consistent with this
           Act) shall apply with any necessary modifications to sums deposited under
           subsection (13) as that section applies to sums deposited under section 57(1)(a) of
           that Act.
 
(15)       The expenses of any such inquiry as is mentioned in subsection (11) or (13) may be
           defrayed out of the money or other property held on trust for the person or persons
           to whom the inquiry relates.
 
430A.      RIGHT OF MINORITY SHAREHOLDER TO BE BOUGHT OUT BY OFFEROR
 
(1)        If a takeover offer relates to all the shares in a company and at any time before
           the end of the period within which the offer can be accepted:
 
           (a)  the offeror has by virtue of acceptances of the offer acquired or contracted
           to acquire some (but not all) of the shares to which the offer relates; and
 
           (b)  those shares, with or without any other shares in the company which he has
           acquired or contracted to acquire, amount to not less than nine-tenths in value of
                all of the shares in the company,
 
           the holder of any shares to which the offer relates who has not accepted the offer
           may by a written communication addressed to the offeror require him to acquire
           those shares.
 
(2)        If takeover offer relates to shares of any class or classes and at any time before
           the end of the period within which the offer can be accepted:
 
           (a)  the offeror has by virtue of acceptances of the offer acquired or contracted
           to acquire some (but not all) of the shares of any class to which the offer
                relates; and
 
           (b)  those shares, with or without any other shares of that class which he has
           acquired or contracted to acquire, amount to not less than nine-tenths in value of
                all the shares of that class,
 
           the holder of any shares of that class who has not accepted the offer may by a
           written communication addressed to the offeror require him to acquire those shares.
 
(3)        Within one month of the time specified in subsection (1) or, as the case may be,
           subsection (2) the offeror shall give any shareholder who has not accepted the
           offer notice in the prescribed manner of the rights that are exercisable by him
           under that subsection; and if the notice is given
</TABLE>
 
                                    APP-F-4
<PAGE>
<TABLE>
<S>        <C>
           before the end of the period mentioned in that subsection it shall state that the
           offer is still open for acceptance.
 
(4)        A notice under subsection (3) may specify a period for the exercise of the rights
           conferred by this section and in that event the rights shall not be exercisable
           after the end of that period; but no such period shall end less than three months
           after the end of the period within which the offer can be accepted.
 
(5)        Subsection (3) does not apply if the offeror has given the shareholder a notice in
           respect of the shares in question under section 429.
 
(6)        If the offeror fails to comply with subsection (3) he and, if the offeror is a
           company, every officer of the company who is in default or to whose neglect the
           failure is attributable, shall be liable to a fine and, for continued
           contravention, to a daily default fine.
 
(7)        If an offeror other than a company is charged with an offence for failing to comply
           with subsection (3) it is a defence for him to prove that he took all reasonable
           steps for securing compliance with that subsection.
 
430B.      EFFECT OF REQUIREMENT UNDER SECTION 430A
 
(1)        The following provisions shall, subject to section 430C, have effect where a
           shareholder exercises his rights in respect of any shares under section 430A.
 
(2)        The offeror shall be entitled and bound to acquire those shares on the terms of the
           offer or on such other terms as may be agreed.
 
(3)        Where the terms of an offer are such as to give the holder of shares a choice of
           consideration the holder of the shares may indicate his choice when requiring the
           offeror to acquire them and the notice given to the holder under section 430A(3):
 
           (a)  shall give particulars of the choice and the rights conferred by this
                subsection; and
 
           (b)  may state which consideration specified in the offer is to be taken as
           applying in default of his indicating a choice;
 
           and the terms of the offer mentioned in subsection (2) shall be determined
           accordingly.
 
(4)        Subsection (3) applies whether or not any time limit or other conditions applicable
           to the choice under the terms of the offer can still be complied with; and if the
           consideration chosen by the holder of the shares:
 
           (a)  is not cash and the offeror is no longer able to provide it; or
 
           (b)  was to have been provided by a third party who is no longer bound or able to
                provide it,
 
           the consideration shall be taken to consist of an amount of cash payable by the
           offeror which at the date when the holder of the shares requires the offeror to
           acquire them is equivalent to the chosen consideration.
 
430C.      APPLICATIONS TO THE COURT
 
(1)        Where a notice is given under section 429 to the holder of any shares the court
           may, on an application made by him within six weeks from the date on which the
           notice was given:
 
           (a)  order that the offeror shall not be entitled and bound to acquire the shares;
                or
 
           (b)  specify terms of acquisition different from those of the offer.
</TABLE>
 
                                    APP-F-5
<PAGE>
<TABLE>
<S>        <C>
(2)        If an application to the court under subsection (1) is pending at the end of the
           period mentioned in subsection (5) of section 430 that subsection shall not have
           effect until the application has been disposed of.
 
(3)        Where the holder of any shares exercises his rights under section 430A the court
           may, on an application made by him or the offeror, order that the terms on which
           the offeror is entitled and bound to acquire the shares shall be such as the court
           thinks fit.
 
(4)        No order for costs or expenses shall be made against a shareholder making an
           application under subsection (1) or (3) unless the court considers:
 
           (a)  that the application was unnecessary, improper or vexatious; or
 
           (b)  that there has been unreasonable delay in making the application or
           unreasonable conduct on his part in conducting the proceedings on the application.
 
(5)        Where a takeover offer has not been accepted to the extent necessary for entitling
           the offeror to give notices under subsection (1) or (2) of section 429 the court
           may, on the application of the offeror, make an order authorizing him to give
           notices under that subsection if satisfied:
 
           (a)  that the offeror has after reasonable enquiry been unable to trace one or more
           of the persons holding shares to which the offer relates;
 
           (b)  that the shares which the offeror has acquired or contracted to acquire by
           virtue of acceptances of the offer, together with the shares held by the person or
                persons mentioned in paragraph (a), amount to not less than the minimum
                specified in that subsection; and
 
           (c)  that the consideration offered is fair and reasonable;
 
           but the court shall not make an order under this subsection unless it considers
           that it is just and equitable to do so having regard, in particular, to the number
           of shareholders who have been traced but who have not accepted the offer.
 
430D.      JOINT OFFERS
 
(1)        A takeover offer may be made by two or more persons jointly and in that event this
           Part of this Act has effect with the following modifications.
 
(2)        The conditions for the exercise of the rights conferred by sections 429 and 430A
           shall be satisfied by the joint offerors acquiring or contracting to acquire the
           necessary shares jointly (as respects acquisitions by virtue of acceptances of the
           offer) and either jointly or separately (in other cases); and subject to the
           following provisions, the rights and obligations of the offeror under those
           sections and sections 430 and 430B shall be respectively joint rights and joint and
           several obligations of the joint offerors.
 
(3)        It shall be a sufficient compliance with any provision of those sections requiring
           or authorizing a notice or other document to be given or sent by or to the joint
           offerors that it is given or sent by or to any of them; but the statutory
           declaration required by section 429(4) shall be made by all of them and, in the
           case of a joint offeror being a company, signed by a director of that company.
 
(4)        In sections 428, 430(8) and 430E references to the offeror shall be construed as
           references to the joint offerors or any of them.
 
(5)        In section 430(6) and (7) references to the offeror shall be construed as
           references to the joint offerors or such of them as they may determine.
 
(6)        In sections 430(4)(a) and 430B(4)(a) references to the offeror being no longer able
           to provide the relevant consideration shall be construed as references to none of
           the joint offerors being able to do so.
</TABLE>
 
                                    APP-F-6
<PAGE>
<TABLE>
<S>        <C>
(7)        In section 430C references to the offeror shall be construed as references to the
           joint offerors except that any application under subsection (3) or (5) may be made
           by any of them and the reference in subsection (5)(a) to the offeror having been
           unable to trace one or more of the persons holding shares shall be construed as a
           reference to none of the offerors having been able to do so.
 
430E.      ASSOCIATES
 
(1)        The requirement in section 428(1) that a takeover offer must extend to all the
           shares, or all the shares of any class or classes, in a company shall be regarded
           as satisfied notwithstanding that the offer does not extend to shares which
           associates of the offeror hold or have contracted to acquire but, subject to
           subsection (2), shares which any such associate holds or has contracted to acquire,
           whether at the time when the offer is made or subsequently, shall be disregarded
           for the purposes of any references in this Part of this Act to the shares to which
           a takeover offer relates.
 
(2)        Where during the period within which a takeover offer can be accepted any associate
           of the offeror acquires or contracts to acquire any of the shares to which the
           offer relates, then, if the condition specified in subsection (8)(a) or (b) of
           section 429 is satisfied as respects those shares they shall be treated for the
           purposes of that section as shares to which the offer relates.
 
(3)        In section 430A(1)(b) and (2)(b) the reference to shares which the offeror has
           acquired or contracted to acquire shall include a reference to shares which any
           associate of his has acquired or contracted to acquire.
 
(4)        In this section "associate," in relation to an offeror, means:
 
           (a)  a nominee of the offeror;
 
           (b)  a holding company, subsidiary or fellow subsidiary of the offeror or a nominee
           of such a holding company, subsidiary or fellow subsidiary;
 
           (c)  a body corporate in which the offeror is substantially interested; or
 
           (d)  any person who is, or is a nominee of, a party to an agreement with the
           offeror for the acquisition of, or of an interest in, the shares which are the
                subject of the takeover offer, being an agreement which includes provisions
                imposing obligations or restrictions such as are mentioned in section
                204(2)(a).
 
(5)        For the purposes of subsection (4)(b) a company is a fellow subsidiary of another
           body corporate if both are subsidiaries of the same body corporate but neither is a
           subsidiary of the other.
 
(6)        For the purposes of subsection (4)(c) an offeror has a substantial interest in a
           body corporate if:
 
           (a)  that body or its directors are accustomed to act in accordance with his
           directions or instructions; or
 
           (b)  he is entitled to exercise or control the exercise of one-third or more of the
           voting power at general meetings of that body.
 
(7)        Subsections (5) and (6) of section 204 shall apply to subsection (4)(d) above as
           they apply to that section and subsections (3) and (4) of section 203 shall apply
           for the purposes of subsection (6) above as they apply for the purposes of
           subsection (2)(b) of that section.
 
(8)        Where the offeror is an individual his associates shall also include his spouse and
           any minor child or stepchild of his.
</TABLE>
 
                                    APP-F-7
<PAGE>
<TABLE>
<S>        <C>
430F.      CONVERTIBLE SECURITIES
 
(1)        For the purposes of this Part of this Act securities of a company shall be treated
           as shares in the company if they are convertible into or entitle the holder to
           subscribe for such shares; and references to the holder of shares or a shareholder
           shall be construed accordingly.
 
(2)        Subsection (1) shall not be construed as requiring any securities to be treated:
 
           (a)  as shares of the same class as those into which they are convertible or for
           which the holder is entitled to subscribe; or
 
           (b)  as shares of the same class as other securities by reason only that the shares
           into which they are convertible or for which the holder is entitled to subscribe
                are of the same class.
</TABLE>
 
                                    APP-F-8
<PAGE>
                                   APPENDIX G
                                KEY DEFINITIONS
 
    In this Prospectus and the accompanying Letter of Transmittal the following
definitions apply, unless the context requires otherwise:
 
Acquisition           The Acquisition Agreement dated as of June 25, 1997
  Agreement           entered into between MMI and Unionamerica.
 
business day          Any day other than a Saturday, Sunday or a U.S. federal
                      holiday and consists of the time period from 12:01 a.m.
                      through 12:00 midnight, New York City time.
 
City Code             The City Code on Takeovers and Mergers of the U.K.
 
Commission            The U.S. Securities and Exchange Commission.
 
Companies Act         The Companies Act 1985 of Great Britain, as amended.
 
Compulsory            A compulsory exchange, pursuant to Sections 428 to 430F of
  Acquisition         the Companies Act on the same terms as the Offer, of all
                      outstanding shares of Unionamerica Common Stock (including
                      those represented by Unionamerica ADSs) to which the Offer
                      relates.
 
Conditions            The conditions to the Offer set out in "The Offer--Terms
                      of the Offer and Proposed Acquisition--Conditions of the
                      Offer".
 
Designated            UA Partners, L.P., Peter J. Cooper, Ian G. Sinclair,
  Affiliates          Robert A. Spass, Steven B. Gruber, Paul H. Warren, Hugh B.
                      Jago, Timothy P. Open, Andrew E. Marks and Alisdair G.
                      Bishop.
 
DGCL                  The General Corporation Law of the State of Delaware, as
                      amended.
 
Dollars or $          U.S. dollars.
 
Exchange Act          The U.S. Securities Exchange Act of 1934, as amended, and
                      the rules and regulations promulgated thereunder.
 
Exchange Agent        ChaseMellon Shareholder Services L.L.C., in its capacity
                      as the Exchange Agent.
 
Exchange Ratio        The 0.836 shares of MMI Common Stock to be exchanged for
                      each Unionamerica ADS pursuant to the terms of the Offer.
 
Expiration Date       12 midnight, New York City time, on December 5, 1997,
                      unless and until MMI shall have extended the Expiration
                      Date in accordance with the terms of the Acquisition
                      Agreement, in which event, the term Expiration Date shall
                      mean the latest time and date on which the Offer, as so
                      extended by MMI, shall be terminated or expire.
 
Governmental or       Any court, tribunal, arbitrator, authority, agency,
  Regulatory          commission, official or other instrumentality of the U.S.,
  Authority           the U.K., or any state, county, city or other political
                      subdivision thereof, or the NYSE.
 
HSR Act               The Hart-Scott-Rodino Antitrust Improvements Act of 1976,
                      as amended, and the rules and regulations promulgated
                      thereunder.
 
IRC                   The U.S. Internal Revenue Code of 1986, as amended.
 
                                    APP-G-1
<PAGE>
<TABLE>
<S>                   <C>
Information Agent     ChaseMellon Shareholder Services L.L.C., in its capacity
                      as the Information Agent.
 
Letter of             The Letter of Transmittal relating to the Offer to be sent
  Transmittal         to Unionamerica Securityholders along with this
                      Prospectus.
 
Minimum Acceptance    The Condition to the Offer relating to the minimum number
  Condition           of acceptances set out in "The Offer--Terms of the Offer
                      and Proposed Acquisition--Conditions of the Offer".
 
MMC                   The Monopolies and Mergers Commission of the U.K.
 
MMI                   MMI Companies, Inc., a Delaware corporation, including, if
                      the context requires, its Subsidiaries.
 
MMI Board             The Board of Directors of MMI.
 
MMI Bylaws            The Amended and Restated Bylaws of MMI.
 
MMI Certificate       The Restated Certificate of Incorporation of MMI.
 
MMI Common Stock      The $0.10 par value common stock of MMI.
 
MMI stockholders      Holders of MMI Common Stock.
 
Noon Buying Rate      The exchange rate of pounds sterling, based on the noon
                      buying rate in New York City for cable transfers in pounds
                      sterling as certified for customs purposes by the Federal
                      Reserve Bank of New York, expressed in dollars per L1.
 
NYSE                  The New York Stock Exchange, Inc.
 
Office of Fair        The Office of Fair Trading of the U.K.
  Trading
 
Offer                 The recommended offer by MMI to acquire the Unionamerica
                      Common Stock (including any stock represented by
                      Unionamerica ADSs) on the terms and subject to the
                      conditions set out in this Prospectus and the Letter of
                      Transmittal including, where the context so permits, any
                      subsequent revision, variation, extension or renewal of
                      such offer.
 
Option holders        Holders of options under the Unionamerica Share Option
                      Schemes.
 
Panel                 The Panel on Takeovers and Mergers of the U.K.
 
Person                An individual, partnership, corporation, limited liability
                      company, association, joint stock company, trust, joint
                      venture, unincorporated association or governmental entity
                      (or any department, agency or political subdivision
                      thereof) and any other entity.
 
Pounds sterling or L  U.K. pounds sterling.
 
Prospectus            This document, including the Appendices hereto, as it may
                      from time to time be amended or supplemented and the
                      Letter of Transmittal.
 
Securities Act        The U.S. Securities Act of 1933, as amended, and the rules
                      and regulations promulgated thereunder.
</TABLE>
 
                                    APP-G-2
<PAGE>
<TABLE>
<S>                   <C>
Selling Stockholders  Those Persons who have executed irrevocable Undertakings
                      to accept the Offer as detailed in paragraph 3(a) of
                      Appendix E-- "Certain Additional Information Required
                      Under the City Code".
 
Subsidiary            With respect to either Unionamerica or MMI, any
                      corporation or other organization, whether incorporated or
                      unincorporated, of which more than 50% of either the
                      equity interests in, or the voting control of, such
                      corporation or other organization is, directly or
                      indirectly through subsidiaries or otherwise, beneficially
                      owned by it.
 
Unionamerica          Unionamerica Holdings plc, a public limited company
                      registered in England and Wales with registered number
                      2822469, including, if the context requires, its
                      Subsidiaries.
 
Unionamerica ADSs     The American Depositary Shares of Unionamerica
                      representing shares of Unionamerica Common Stock now in
                      issue and any further such securities which are issued
                      after the date of this Prospectus and while the Offer
                      remains open (or such earlier date as MMI may determine,
                      subject to the City Code and the terms of the Acquisition
                      Agreement) and including the underlying shares of
                      Unionamerica Common Stock represented by such American
                      Depositary Shares.
 
Unionamerica          The Articles of Association of Unionamerica.
  Articles
 
Unionamerica Board    The Board of Directors of Unionamerica.
 
Unionamerica Common   The ordinary shares of $0.0448 each of Unionamerica now in
  Stock               issue and any further such shares which are
                      unconditionally allotted or issued fully paid after the
                      date of this Prospectus and while the Offer remains open
                      for acceptance (or such earlier date as MMI may, subject
                      to the City Code and the terms of the Acquisition
                      Agreement, determine), whether pursuant to the exercise of
                      options under the Unionamerica Share Option Schemes or
                      otherwise.
 
Unionamerica          Unionamerica Common Stock together with Unionamerica ADSs.
  Securities
 
Unionamerica          A holder of Unionamerica ADSs.
  Securityholder
 
Unionamerica Share    The Unionamerica Holdings plc Unapproved Executive Share
  Option Schemes      Option Scheme and The Unionamerica Holdings plc 1996
                      Executive Share Option Scheme.
 
U.K.                  United Kingdom of Great Britain and Northern Ireland.
 
U.S.                  United States of America, its territories and possessions,
                      any State of the United States and the District of
                      Columbia.
</TABLE>
 
                                    APP-G-3
<PAGE>
    Questions and requests for assistance and additional copies of this
Prospectus, the Letter of Transmittal, and other enclosures may be directed to:
 
<TABLE>
<S>                                       <C>
The Information Agent:                    ChaseMellon Shareholder Services L.L.C.
                                          450 West 33rd Street
                                          New York, NY 10001
                                          1-800-549-9249
 
The Exchange Agent:                       ChaseMellon Shareholder Services L.L.C.
                                          P.O. Box 3300
                                          South Hackensack, NJ 07606
                                          1-800-777-3674
 
or to
 
The Dealer Manager:                       Smith Barney Inc.
                                          388 Greenwich Street
                                          New York, NY 10013
                                          1-212-816-8541
</TABLE>

<PAGE>
    THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION. If you are
in any doubt about what action to take in connection with the Offer, you should
immediately consult your stockbroker, bank manager, attorney or accountant or an
independent financial advisor authorized under the United Kingdom Financial
Services Act 1986.
 
    If you have sold or otherwise transferred any or all of your Unionamerica
ADSs, please forward this document with the accompanying Prospectus, reply-paid
envelope and other enclosures as soon as possible to the purchaser or other
transferee, or to the agent through whom the sale or transfer was effected for
transmission to the purchaser or other transferee. However, such documents
should not be forwarded to or transmitted in or into Australia or Japan or to a
resident of Australia or Japan.
 
                             LETTER OF TRANSMITTAL
 
                                  TO EXCHANGE
                         0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
             FOR EACH OF THE OUTSTANDING AMERICAN DEPOSITARY SHARES
                  EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS OF
                           UNIONAMERICA HOLDINGS PLC
             REPRESENTING ALL OF THE OUTSTANDING ORDINARY SHARES OF
                           UNIONAMERICA HOLDINGS PLC
 
                  PURSUANT TO THE OFFER TO EXCHANGE/PROSPECTUS
                             DATED NOVEMBER 5, 1997
 
- --------------------------------------------------------------------------------
    THIS OFFER WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON DECEMBER 5,
   1997, UNLESS THE OFFER IS EXTENDED IN ACCORDANCE WITH THE TERMS OF THE
   ACQUISITION AGREEMENT BETWEEN MMI COMPANIES, INC. AND UNIONAMERICA HOLDINGS
   PLC, DATED JUNE 25, 1997 (THE "EXPIRATION DATE"). UNIONAMERICA ADSS WHICH
   ARE TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO
   THE EXPIRATION DATE (OTHER THAN THOSE UNIONAMERICA ADSS WHICH ARE TENDERED
   BY CERTAIN UNIONAMERICA SECURITYHOLDERS (THE "SELLING STOCKHOLDERS") WHO
   HAVE EXECUTED IRREVOCABLE UNDERTAKINGS TO ACCEPT THE OFFER (THE
   "UNDERTAKINGS")). AT THE EXPIRATION DATE, INCLUDING ANY EXTENSION THEREOF,
   AND UPON SATISFACTION OR, WHERE PERMITTED, WAIVER OF THE CONDITIONS OF THE
   OFFER, ALL UNIONAMERICA ADSS VALIDLY TENDERED AND NOT VALIDLY WITHDRAWN
   WILL BE EXCHANGED.
- --------------------------------------------------------------------------------
 
                      THE EXCHANGE AGENT FOR THE OFFER IS:
 
                    CHASEMELLON SHAREHOLDER SERVICES L.L.C.
 
<TABLE>
<S>                          <C>                          <C>
         BY MAIL:                    BY COURIER:               BY HAND DELIVERY:
       P.O. Box 3301             85 Challenger Road         ChaseMellon Shareholder
                                                                    Services
   Attn: Reorganization         Attn: Reorganization        120 Broadway, 13th Floor
        Department                   Department
South Hackensack, NJ 07606    Ridgefield Park, NJ 07660        New York, NY 10271
</TABLE>
 
DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET FORTH
    ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. YOU MUST SIGN THIS LETTER
         OF TRANSMITTAL IN THE APPROPRIATE SPACE THEREFOR PROVIDED
            BELOW. THE INSTRUCTIONS ACCOMPANYING THIS LETTER OF
                TRANSMITTAL SHOULD BE READ CAREFULLY BEFORE
                       THIS LETTER OF TRANSMITTAL IS
                                   COMPLETED.
<PAGE>
    This Letter of Transmittal is to be completed by holders of Unionamerica
ADSs (as defined below), if American Depositary Receipts representing
Unionamerica ADSs ("Unionamerica ADRs") are to be forwarded herewith to the
Exchange Agent at the address set forth in this Letter of Transmittal or if
delivery of Unionamerica ADSs is to be made by book-entry transfer ("Book-Entry
Transfer") to the Exchange Agent's account at ChaseMellon Shareholder Services
L.L.C. or The Depository Trust Company (each a "Book-Entry Transfer Facility"
and collectively, the "Book-Entry Transfer Facilities") pursuant to the
book-entry transfer procedure described in "THE OFFER--Procedures for Tendering
Unionamerica ADSs--Book-Entry Transfer" of the Prospectus (as defined below).
Holders of Unionamerica ADSs whose Unionamerica ADRs are not immediately
available or who cannot deliver such Unionamerica ADRs and all other required
documents to the Exchange Agent prior to the Expiration Date or who cannot
complete the procedures for Book-Entry Transfer on a timely basis, may tender
their Unionamerica ADSs only by following the procedures and meeting the
conditions for guaranteed delivery set forth in "THE OFFER--Procedures for
Tendering Unionamerica ADSs--Guaranteed Delivery Procedures". See the
instructions to this Letter of Transmittal. Delivery of documents to a
Book-Entry Transfer Facility does not constitute delivery to the Exchange Agent.
 
/ /  CHECK HERE IF UNIONAMERICA ADSs ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER
    TO THE EXCHANGE AGENT'S ACCOUNT AT ONE OF THE BOOK-ENTRY TRANSFER FACILITIES
    AND COMPLETE THE FOLLOWING (ONLY PARTICIPANTS IN A BOOK-ENTRY TRANSFER
    FACILITY MAY DELIVER UNIONAMERICA ADSs BY BOOK-ENTRY TRANSFER):
 
    Name of Tendering Institution ______________________________________________
 
    Account Number _____________________________________________________________
 
    Check Box of Applicable Book-Entry Transfer Facility:
 
        (check one)
 
    / /  The Depository Trust Company  / /  ChaseMellon Shareholder Services
    L.L.C.
 
    Transaction Code Number ____________________________________________________
 
/ /  CHECK HERE IF UNIONAMERICA ADSs ARE BEING TENDERED PURSUANT TO A NOTICE OF
    GUARANTEED DELIVERY PREVIOUSLY SENT TO THE EXCHANGE AGENT AND COMPLETE THE
    FOLLOWING:
 
    Name(s) of Registered Holder(s) ____________________________________________
 
    Window Ticket No. (if any) _________________________________________________
 
    Date of Execution of Notice of Guaranteed Delivery _________________________
 
    Name of Institution which Guaranteed Delivery ______________________________
 
    IF DELIVERY IS BY BOOK-ENTRY TRANSFER, CHECK BOX OF APPLICABLE BOOK-ENTRY
    TRANSFER FACILITY:
 
        / /  The Depository Trust Company
 
        / /  ChaseMellon Shareholder Services L.L.C.
 
             Account Number: ___________________________________________________
          Transaction Code Number: _____________________________________________
 
                                       2
<PAGE>
<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------
                         DESCRIPTION OF UNIONAMERICA ADSS TENDERED
- ---------------------------------------------------------------------------
    NAME(S) AND ADDRESS(S) OF
REGISTERED HOLDER(S) (PLEASE FILL
IN, IF BLANK, EXACTLY AS NAME(S)      UNIONAMERICA ADR(S) AND UNIONAMERICA ADSS TENDERED
APPEAR(S) ON UNIONAMERICA ADR(S))           (ATTACH ADDITIONAL LIST, IF NECESSARY)
<S>                                <C>          <C>            <C>            <C>
- ----------------------------------------------------------------------------
 
<CAPTION>
                                                TOTAL NUMBER
                                                     OF
                                                UNIONAMERICA   TOTAL NUMBER
                                                    ADSS            OF          NUMBER OF
                                                  EVIDENCED    CERTIFICATED       BOOK-
                                   UNIONAMERICA      BY        UNIONAMERICA       ENTRY
                                       ADR      UNIONAMERICA       ADSS       UNIONAMERICA
                                   NUMBER(S)*      ADR(S)*      TENDERED**    ADSS TENDERED
<S>                                <C>          <C>            <C>            <C>
- ----------------------------------------------------------------------------
- ---------------------------------------------------------------------------
 THE UNIONAMERICA ADSS LISTED ABOVE TENDERED PURSUANT TO THIS LETTER OF TRANSMITTAL ARE
 REGISTERED AT THE FOLLOWING VP ACCOUNT:
 
  / /  / /  / /  / /    / /  / /  / /  / /    / /  / /  / /  / /
 
 IF THE ABOVE VP ACCOUNT IS A TRANSFER ACCOUNT, PLEASE ASK YOUR BANK TO RE-REGISTER IT AS
 SOON AS POSSIBLE.
- ---------------------------------------------------------------------------
  *  Need not be completed by stockholders delivering Unionamerica ADSs by book-entry
 transfer.
 **  Unless otherwise indicated, it will be assumed that all Unionamerica ADSs evidenced by
     each Unionamerica ADR delivered to the Exchange Agent are being tendered hereby. See
     Instruction 4.
- ----------------------------------------------------------------------------
</TABLE>
 
                    NOTE: SIGNATURES MUST BE PROVIDED BELOW
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY
 
Ladies and Gentlemen:
 
    The undersigned hereby delivers to ChaseMellon Shareholder Services L.L.C.
(the "Exchange Agent") to hold as agent for the undersigned (a) this Letter of
Transmittal, (b) securities of Unionamerica Holdings plc, a corporation
registered in England and Wales under the Companies Act 1985 of Great Britain,
as amended, with registered number 2822469 ("Unionamerica"), and (c) all other
documents required to be delivered by the undersigned prior to the Expiration
Date.
 
    The undersigned is delivering the foregoing to facilitate acceptance by the
undersigned of the exchange offer by MMI Companies, Inc., a Delaware corporation
("MMI"), upon the terms and conditions set forth in the Offer to
Exchange/Prospectus dated November 5, 1997, and any supplements or amendments
thereto (the "Prospectus"), pursuant to which MMI has made an offer (the
"Offer") to exchange for each outstanding American Depositary Share, each
representing one Ordinary Share, nominal value $0.0448 per share, of
Unionamerica (a "Unionamerica ADS"), 0.836 shares of common stock, par value
$0.10 per share, of MMI (the "MMI Common Stock"). Each share of MMI Common Stock
issued in connection with the Offer will be accompanied by a right (a "Right")
which will entitle the registered holder thereof to purchase from MMI a unit
consisting of one one-hundredth of a share (a "Unit") of Series B Junior
Participating Preferred Stock of MMI, par value $20.00 per share, at a purchase
price of $75.00 per Unit, subject to adjustment, pursuant to a Rights Agreement
between MMI and ChaseMellon Shareholder Services L.L.C., as Rights Agent.
Capitalized terms and certain other terms used in this Letter of Transmittal and
not otherwise defined herein shall have the respective meanings assigned to them
in the Prospectus.
 
                                       3
<PAGE>
    The Prospectus and this Letter of Transmittal comprise the sole offering
documents in connection with the Offer, receipt of which are hereby acknowledged
by the undersigned.
 
    At the Expiration Date, unless Unionamerica ADSs have been properly
withdrawn or the Exchange Agent has received contrary instructions from the
undersigned, the undersigned hereby instructs the Exchange Agent to (i) tender
all Unionamerica ADSs legally owned by the undersigned and delivered to the
Exchange Agent pursuant to this Letter of Transmittal and (ii) accept the Offer
on behalf of the undersigned in the manner indicated below subject to the terms
and conditions set forth in this Letter of Transmittal and the Prospectus by
informing MMI in writing that its Offer has been so accepted.
 
    The undersigned hereby acknowledges that, following the Expiration Date,
delivery of this Letter of Transmittal and of the Unionamerica ADSs and other
required documents furnished by the undersigned to the Exchange Agent in
connection herewith will be deemed (without any further action by the Exchange
Agent) to constitute acceptance of the Offer to the extent indicated above by
the undersigned, subject to the terms and conditions set forth in this Letter of
Transmittal and the Prospectus.
 
    Subject to, and effective upon, acceptance of Unionamerica ADSs tendered
herewith in accordance with the terms of the Offer (including, if the Offer is
extended or amended, the terms or conditions of any such extension or
amendment), the undersigned hereby sells, assigns and transfers to the order of
MMI all right, title and interest in and to all Unionamerica ADSs that are being
tendered hereby, and irrevocably constitutes and appoints the Exchange Agent the
true and lawful agent and attorney-in-fact of the undersigned with respect to
such Unionamerica ADSs with full power of substitution (such power of attorney
being deemed to be an irrevocable power coupled with an interest), to (i) in the
case of Unionamerica ADSs, deliver Unionamerica ADRs for such Unionamerica ADSs
or transfer ownership of such Unionamerica ADSs on the account books maintained
by a Book-Entry Transfer Facility, together, in either such case, with all
accompanying evidences of transfer and authenticity to, or upon the order of
MMI, as the case may be, (ii) present such Unionamerica ADSs for transfer on the
books of the clearing agency on whose books the Unionamerica ADSs are
maintained, and (iii) receive all benefits and otherwise exercise all rights of
beneficial ownership of such Unionamerica ADSs, all in accordance with the terms
of the Offer.
 
    The undersigned hereby irrevocably appoints the designees of MMI, and each
of them, as the attorneys-in-fact and proxies of the undersigned, each with full
power of substitution, and agrees that effective from and after the date the
Offer becomes or is declared unconditional in all respects and subject to
applicable withdrawal rights, (a) MMI shall, in its absolute discretion, be
entitled to direct the exercise of any votes attaching to any Unionamerica
Common Stock represented by Unionamerica ADSs in respect of which the Offer has
been accepted or is deemed to have been accepted and any other rights and
privileges attaching to such Unionamerica Common Stock represented by
Unionamerica ADSs, including any right to requisition a general meeting of
Unionamerica or of any class of its shareholders and (b) the execution of this
Letter of Transmittal and its delivery to the Exchange Agent will constitute (i)
an authority to Unionamerica and the Exchange Agent or their respective agents
from the undersigned to send any notice, circular, warrant, document or other
communication which may be sent to him or her as a Unionamerica Securityholder
to MMI at its registered office, (ii) an authority to MMI or its agents to sign
any consent to short notice of a general meeting or separate class meeting on
the undersigned's behalf and/ or to execute a form of proxy in respect of such
Unionamerica ADSs appointing any person nominated by MMI to attend general
meetings or separate class meetings of Unionamerica (or any adjournments of such
meetings) and to exercise the votes attaching to such Unionamerica ADSs on his
or her behalf and (iii) the agreement of the undersigned not to exercise any
such rights without the consent of MMI and the irrevocable undertaking of the
undersigned not to appoint a proxy for or to attend general meetings or separate
class meetings. This proxy and power of attorney is coupled with an interest in
the Unionamerica ADSs tendered hereby, is irrevocable and is granted in
consideration of, and is effective upon, the acceptance for exchange of such
Unionamerica ADSs by MMI in accordance with the terms of the Offer. Such
acceptance for exchange shall revoke all other proxies and powers of attorney
granted by the undersigned at any time with respect to such Unionamerica ADSs,
and no subsequent proxy or power of
 
                                       4
<PAGE>
attorney shall be given or written consent executed (and if given or executed,
shall be void) by the undersigned with respect thereto. The undersigned
understands that, in order for Unionamerica ADSs to be deemed validly tendered,
immediately upon MMI's acceptance of such Unionamerica ADSs, MMI must be able to
exercise full voting and other rights with respect to such Unionamerica ADSs,
including, without limitation, voting at any meeting of Unionamerica
Securityholders.
 
    The undersigned hereby represents and warrants that the undersigned has full
power and authority to tender, sell, assign and transfer the Unionamerica ADSs
tendered hereby, and that, when such Unionamerica ADSs are accepted by MMI, MMI
will acquire good and marketable title thereto, free and clear of all liens,
restrictions, charges and encumbrances, and that none of such Unionamerica ADSs
will be subject to any adverse claim. The undersigned will, upon request,
execute and deliver all additional documents deemed by the Exchange Agent or MMI
to be necessary or desirable to complete the sale, assignment, or transfer of
the Unionamerica ADSs tendered hereby.
 
    No authority, power of attorney or proxy herein conferred or agreed to be
conferred shall be affected by, and all such authority shall survive, the death
or incapacity of the undersigned. All obligations of the undersigned hereunder
shall be binding upon the heirs, personal representatives, successors and
assigns of the undersigned. Except as stated in the Prospectus, all tenders made
pursuant to this Letter of Transmittal are irrevocable.
 
    The undersigned understands that tenders of Unionamerica ADSs pursuant to
any one of the procedures described herein and in "THE OFFER--Procedures for
Tendering Unionamerica ADSs" of the Prospectus will constitute the undersigned's
acceptance of the terms and conditions of the Offer. MMI's acceptance of such
Unionamerica ADSs will constitute a binding agreement between the undersigned
and MMI upon the terms and subject to the conditions of the Offer.
 
    The undersigned agrees and acknowledges that he or she is not a customer (as
defined in the rules of The Securities and Futures Authority Limited of the
United Kingdom) of Smith Barney Inc., Smith Barney Europe, Ltd., or Donaldson,
Lufkin & Jenrette Securities Corporation in connection with the Offer or in
connection with advice given by Smith Barney Inc. to the Board of Directors of
MMI or Donaldson, Lufkin & Jenrette Securities Corporation to the Board of
Directors of Unionamerica and neither Smith Barney Inc., Smith Barney Europe,
Ltd., nor Donaldson, Lufkin & Jenrette Securities Corporation will be
responsible to anyone other than those to whom they are providing advice for
providing the protections afforded to their customers or for providing advice in
relation to the matters described in this document.
 
    Unless otherwise indicated herein in the box entitled "Special Exchange
Instructions", please issue the certificates for shares of MMI Common Stock
and/or return all Unionamerica ADSs not accepted or not tendered in the name(s)
of the registered holder(s) appearing above under "Description of Unionamerica
ADSs Tendered". Similarly, unless otherwise indicated in the box entitled
"Special Delivery Instructions", please mail the certificates for the shares of
MMI Common Stock and/or all Unionamerica ADSs not tendered or not accepted (and
accompanying documents, as appropriate) to the address(es) of the registered
holder(s) appearing above under "Description of Unionamerica ADSs Tendered". In
the event that the boxes entitled "Special Exchange Instructions" and "Special
Delivery Instructions" are both completed, please issue the certificates for
shares of MMI Common Stock and/or return all Unionamerica ADSs not accepted or
not tendered in the name(s) of, and mail such certificates for shares of MMI
Common Stock and/or Unionamerica ADRs to, the person(s) so indicated. In the
case of any Unionamerica ADSs tendered hereby and delivered by Book-Entry
Transfer, unless otherwise indicated herein in the box entitled "Special
Exchange Instructions", please credit any such Unionamerica ADSs tendered that
are not accepted by crediting the account at the Book-Entry Transfer Facility
designated above. The undersigned recognizes that MMI has no obligation,
pursuant to the Special Exchange Instructions, to transfer any Unionamerica ADSs
from the name of the registered holder(s) thereof if MMI does not accept for
exchange any of the Unionamerica ADSs tendered hereby.
 
    The execution of this Letter of Transmittal constitutes the submission of
the undersigned, in relation to all matters arising out of the Offer or the
Letter of Transmittal, to the jurisdiction of the courts of England.
 
    The terms and conditions of the Offer contained in the Prospectus shall be
deemed to be incorporated in, and form part of, this Letter of Transmittal,
which shall be read and construed accordingly.
 
                                       5
<PAGE>
/ /  Check here if any of the Unionamerica ADRs representing Unionamerica ADSs
     that you own have been lost or destroyed and see Instruction 10.
 
Number of Unionamerica ADSs represented by lost, stolen or destroyed
Unionamerica ADRs: _____________________________________________________________
 
- -------------------------------------------
 
                         SPECIAL EXCHANGE INSTRUCTIONS
 
                        (SEE INSTRUCTIONS 1, 5, 6 AND 7)
 
      To be completed ONLY if the certificates for shares of MMI Common Stock,
  and/or any check to be issued for cash in lieu of fractional shares, or
  Unionamerica ADSs not tendered or not accepted are to be issued in the name
  of someone other than the undersigned, or if Unionamerica ADSs tendered
  hereby and delivered by book-entry transfer that are not accepted are to be
  returned by credit to an account at one of the Book-Entry Transfer
  Facilities other than that designated above.
 
  Issue
 
  / /  Certificate(s) to:
  Name _______________________________________________________________________
                                 (PLEASE PRINT)
 
  Address ____________________________________________________________________
 
  ____________________________________________________________________________
                                (ZIP/POST CODE)
 
  / /  Credit Unionamerica ADSs tendered by book-entry transfer and not
       accepted to the account set forth below:
 
  Check appropriate box:
 
  / /  The Depository Trust Company
 
  / /  ChaseMellon Shareholder Services L.L.C.
 
  Account Number:
 
  -----------------------------------------------
  -----------------------------------------------
 
                         SPECIAL DELIVERY INSTRUCTIONS
 
                            (SECTIONS 1, 5, 6 AND 7)
 
      To be completed ONLY if the certificates for shares of MMI Common Stock,
  and/or any check to be issued for cash in lieu of fractional shares, or
  Unionamerica ADSs not tendered or not accepted are to be mailed to someone
  other than the undersigned, or the undersigned at an address other than that
  shown under "Description of Unionamerica ADSs Tendered".
 
  Mail
 
  / /  Certificate(s) to:
 
  Name _______________________________________________________________________
                                 (PLEASE PRINT)
 
  Address ____________________________________________________________________
 
  ____________________________________________________________________________
 
  ____________________________________________________________________________
                                (ZIP/POST CODE)
 
- -----------------------------------------------------
 
                                       6
<PAGE>
- --------------------------------------------------------------------------------
 
                                   IMPORTANT
                    UNIONAMERICA SECURITYHOLDERS: SIGN HERE
 
  ____________________________________________________________________________
 
  ____________________________________________________________________________
                           SIGNATURE(S) OF HOLDER(S)
 
  Dated: __________________, 1997
 
      (Must be signed by registered holder(s) exactly as name(s) appear(s) on
  Unionamerica ADRs or on a security position listing by person(s) authorized
  to become registered holder(s) by certificates and documents transmitted
  herewith. If signature is by a trustee, executor, administrator, guardian,
  attorney-in-fact, officer of a corporation or other person acting in a
  fiduciary or representative capacity, please provide the following
  information and see Instruction 5).
 
  Name(s): ___________________________________________________________________
  ____________________________________________________________________________
                                  PLEASE PRINT
 
  Capacity (full title): _____________________________________________________
 
  Address: ___________________________________________________________________
 
  ____________________________________________________________________________
                             INCLUDE ZIP/POST CODE
 
  Area Code and Telephone No: (  )____________________________________________
 
                           GUARANTEE OF SIGNATURE(S)
                           (SEE INSTRUCTIONS 1 AND 5)
 
  Authorized Signature: ______________________________________________________
 
  Name: ______________________________________________________________________
                             (PLEASE TYPE OR PRINT)
 
  Title: _____________________________________________________________________
 
  Name of Firm: ______________________________________________________________
 
  Address: ___________________________________________________________________
 
  ____________________________________________________________________________
  ----------------------------------------------------------------------------
 
                                       7
<PAGE>
                                  INSTRUCTIONS
             FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER
 
    1.  GUARANTEE OF SIGNATURES.  All signatures on this Letter of Transmittal
must be guaranteed by a financial institution (including most banks, savings and
loan associations and brokerage houses) which is a participant in the Securities
Transfer Agents Medallion Program, the New York Stock Exchange Medallion
Signature Program or the New York Stock Exchange Medallion Program (each of the
foregoing being referred to as an "Eligible Institution") unless (i) this Letter
of Transmittal is signed by the registered holder(s) of the Unionamerica ADSs
(which term, for purposes of this document, shall include any participant in a
Book-Entry Transfer Facility whose name appears on a security position listing
as the owner of Unionamerica ADSs) tendered hereby and such holder(s) has (have)
completed neither the box entitled "Special Exchange Instructions" nor the box
entitled "Special Delivery Instructions" on the reverse hereof or (ii) such
Unionamerica ADSs are tendered for the account of an Eligible Institution. See
Instruction 5 of this Letter of Transmittal.
 
    2.  DELIVERY OF LETTER OF TRANSMITTAL AND UNIONAMERICA ADRS; BOOK-ENTRY
TRANSFER.  This Letter of Transmittal is to be used if Unionamerica ADRs are to
be forwarded herewith or if Unionamerica ADSs are to be delivered by Book-Entry
Transfer pursuant to the procedure set forth in "THE OFFER-- Procedures for
Tendering Unionamerica ADSs" of the Prospectus. This Letter of Transmittal or a
facsimile copy hereof properly completed and duly executed, together with any
other documents required by this Letter of Transmittal and Unionamerica ADRs
evidencing tendered Unionamerica ADSs, must be received by the Exchange Agent at
one of its addresses set forth on the reverse hereof prior to the Expiration
Date (as defined in Appendix G of the Prospectus--"Key Definitions"). In order
for a Unionamerica Securityholder to validly tender such Unionamerica ADSs (a)
this Letter of Transmittal and other required documents (including the
Unionamerica ADRs) must be delivered as described in the preceding sentence and
(b) in the case of Unionamerica Securityholders tendering their Unionamerica
ADSs pursuant to a Book-Entry Transfer, an Agent's Message (as defined below)
and any other required documents, must be received by the Exchange Agent at one
of its addresses set forth on the reverse hereof, and either Unionamerica ADRs
must be received by the Exchange Agent at one of such addresses or be delivered
by Book-Entry Transfer and a confirmation thereof must be received by the
Exchange Agent, in each case prior to the Expiration Date. Holders whose
Unionamerica ADRs are not immediately available, who cannot deliver their
Unionamerica ADRs and all other required documents to the Exchange Agent prior
to the Expiration Date or who cannot complete the procedure for delivery of
Unionamerica ADSs by Book-Entry Transfer on a timely basis may tender their
Unionamerica ADSs pursuant to the guaranteed delivery procedures described in
"THE OFFER--Procedures for Tendering Unionamerica ADSs-- Guaranteed Delivery
Procedures" of the Prospectus. Pursuant to such procedure: (i) such tender must
be made by or through an Eligible Institution; (ii) a properly completed and
duly executed Notice of Guaranteed Delivery, substantially in the form provided
by MMI, must be received by the Exchange Agent prior to the Expiration Date; and
(iii) the Unionamerica ADRs (or, in the case of delivery by Book-Entry Transfer,
timely confirmation of the Book-Entry Transfer of such Unionamerica ADSs into
the Exchange Agent's account at a Book-Entry Transfer Facility) in proper form
for transfer by delivery, in each case, together with this Letter of Transmittal
(or a facsimile thereof), properly completed and duly executed, with any
required signature guarantees and any other documents required by this Letter of
Transmittal, must be received by the Exchange Agent within three New York Stock
Exchange, Inc. ("NYSE") trading days after the date of execution of such Notice
of Guaranteed Delivery, all as described in "THE OFFER--Procedures for Tendering
Unionamerica ADSs" of the Prospectus.
 
    The term "Agent's Message" means a message transmitted by a Book-Entry
Transfer Facility to, and received by, the Exchange Agent and forming a part of
a Book-Entry Confirmation, which states that such Book-Entry Transfer Facility
has received an express acknowledgment from the participant in such Book-Entry
Transfer Facility tendering Unionamerica ADSs that such participant has received
and agrees to be
 
                                       8
<PAGE>
bound by the terms of this Letter of Transmittal and that MMI may enforce such
agreement against the participant.
 
    IF UNIONAMERICA ADRS ARE FORWARDED SEPARATELY TO THE EXCHANGE AGENT, A
PROPERLY COMPLETED AND DULY EXECUTED LETTER OF TRANSMITTAL MUST ACCOMPANY EACH
SUCH DELIVERY.
 
    THE METHOD OF DELIVERY OF THIS LETTER OF TRANSMITTAL, UNIONAMERICA ADRS AND
ALL OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH ANY BOOK-ENTRY TRANSFER
FACILITY, IS AT THE OPTION AND RISK OF THE TENDERING UNIONAMERICA
SECURITYHOLDER, AND THE DELIVERY WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED
BY THE EXCHANGE AGENT. IF DELIVERY IS BY MAIL, REGISTERED MAIL WITH RETURN
RECEIPT REQUESTED, PROPERLY INSURED, IS RECOMMENDED. IN ALL CASES, SUFFICIENT
TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.
 
    No alternative, conditional or contingent tenders will be accepted and no
fractional Unionamerica ADSs will be accepted. By execution of this Letter of
Transmittal (or a facsimile hereof), all tendering stockholders waive any right
to receive any notice of the acceptance of their Unionamerica ADSs for payment.
 
    3.  INADEQUATE SPACE.  If the space provided herein under "Description of
Unionamerica ADSs Tendered" is inadequate, the Unionamerica ADR numbers, the
number of Unionamerica ADSs evidenced by such Unionamerica ADRs, and the number
of Book-Entry Unionamerica ADSs tendered should be listed on a separate schedule
and attached hereto.
 
    4.  PARTIAL TENDERS (NOT APPLICABLE TO HOLDERS OF UNIONAMERICA ADSS WHO
TENDER BY BOOK-ENTRY TRANSFER). If fewer than all the Unionamerica ADSs
evidenced by any Unionamerica ADR delivered to the Exchange Agent herewith are
to be tendered hereby, fill in the number of Unionamerica ADSs that are to be
tendered in the box entitled "Total Number of Unionamerica ADSs Tendered". In
such cases, new Unionamerica ADR(s) evidencing the remainder of the Unionamerica
ADSs that were evidenced by the Unionamerica ADRs delivered to the Exchange
Agent herewith will be sent to the person(s) signing this Letter of Transmittal,
unless otherwise provided in the box entitled "Special Delivery Instructions" on
the reverse hereof, as soon as practicable after the expiration or termination
of the Offer. All Unionamerica ADSs evidenced by Unionamerica ADRs delivered to
the Exchange Agent will be deemed to have been tendered unless otherwise
indicated.
 
    5.  SIGNATURES ON LETTER OF TRANSMITTAL; STOCK POWERS AND ENDORSEMENTS.  If
this Letter of Transmittal is signed by the registered holder(s) of the
Unionamerica ADSs tendered hereby, the signature(s) must correspond with the
name(s) as written on the face of the Unionamerica ADRs without alteration,
enlargement or any other change whatsoever.
 
    If any Unionamerica ADS tendered hereby is owned of record by two or more
persons, all such persons must sign this Letter of Transmittal.
 
    If this Letter of Transmittal is signed by the registered holder(s) of the
Unionamerica ADSs tendered hereby, no separate stock powers or, in the case of
Unionamerica ADSs, no endorsements of Unionamerica ADRs are required, unless
issuance of certificates for shares of MMI Common Stock, and/or any check for
cash in lieu of fractional shares, is to be made to, or Unionamerica ADRs not
tendered or not accepted are to be issued in the name of, a person other than
the registered holder(s), in which case the Unionamerica ADR(s) tendered hereby
must be endorsed or accompanied by appropriate stock powers, in either case
signed exactly as the name(s) of the registered holder(s) appear(s) on such
Unionamerica ADR(s). Signatures on such Unionamerica ADR(s) and stock powers
must be guaranteed by an Eligible Institution.
 
    If this Letter of Transmittal is signed by a person other than the
registered holder(s) of the Unionamerica ADSs tendered hereby, the Unionamerica
ADR(s) tendered hereby must be endorsed or accompanied by appropriate stock
powers, in either case signed exactly as the name(s) of the registered
 
                                       9
<PAGE>
holder(s) appear(s) on such Unionamerica ADR(s). Signatures on such Unionamerica
ADR(s) and stock powers must be guaranteed by an Eligible Institution.
 
    If this Letter of Transmittal or any Unionamerica ADR or stock power is
signed by a trustee, executor, administrator, guardian, attorney-in-fact,
officer of a corporation or other person acting in a fiduciary or representative
capacity, such person should so indicate when signing, and, unless waived by the
Exchange Agent, proper evidence satisfactory to the Exchange Agent of such
person's authority so to act must be submitted.
 
    6.  TRANSFER TAXES.  MMI will pay or, cause to be paid any applicable
transfer taxes with respect to the transfer and sale of Unionamerica ADSs to it
or its order pursuant to the Offer. If, however, delivery of the consideration
in respect of the Offer is to be made to, or if Unionamerica ADRs not tendered
or accepted pursuant to the Offer, are to be registered in the name of any
person other than the registered holder(s), or if Unionamerica ADRs are
registered in the name of any person other than the person(s) signing this
Letter of Transmittal, the tendering holder must provide satisfactory evidence
of the payment of any applicable transfer taxes (whether imposed on the
registered holder(s) or such person) payable on account of the transfer to such
person prior to the delivery of the consideration pursuant to the Offer.
 
    7.  SPECIAL EXCHANGE AND DELIVERY INSTRUCTIONS.  If certificates for shares
of MMI Common Stock and/ or any check for cash in lieu of fractional shares,
and/or Unionamerica ADRs not tendered or accepted pursuant to the Offer, are to
be issued in the name of a person other than the signer of this Letter of
Transmittal, or if certificates for shares of MMI Common Stock and/or any check
for cash in lieu of fractional shares, are to be sent, and/or such Unionamerica
ADRs are to be returned, to a person other than the signer of this Letter of
Transmittal or to an address other than that shown above, the appropriate boxes
on this Letter of Transmittal should be completed. Holders of Unionamerica ADSs
tendering such Unionamerica ADSs by Book-Entry Transfer may request that
Unionamerica ADSs not accepted pursuant to the Offer be credited to such account
maintained at any of the Book-Entry Transfer Facilities as such holder may
designate under "Special Exchange Instructions". If no such instructions are
given, Unionamerica ADSs tendered by Book-Entry Transfer and not accepted
pursuant to the Offer will be returned by crediting the account at the
Book-Entry Transfer Facility designated herein.
 
    8.  QUESTIONS AND REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Questions
and requests for assistance may be directed to the Information Agent or the
Dealer Manager at their respective addresses or telephone numbers set forth
below. Additional copies of the Prospectus, this Letter of Transmittal and the
Notice of Guaranteed Delivery may be obtained from the Information Agent or from
certain brokers, dealers, commercial banks or trust companies.
 
    9.  WAIVER OF CONDITIONS TO THE OFFER.  MMI reserves the right, subject to
the provisions of the Acquisition Agreement, applicable law and the rules of the
City Code, to waive, in whole or in part, all or any of Conditions (a) to (w)
inclusive (although, Conditions (c), (f), (g), (h) and (v) have already been
satisfied) provided that MMI may only waive those of Conditions (a) to (l) with
the prior written consent of Unionamerica. Unionamerica reserves the right,
subject to the provisions of the Acquisition Agreement, to waive, in whole or in
part, all or any of Conditions (x) and (y). Reducing the Minimum Acceptance
Condition requires the prior written consent of Unionamerica and the Minimum
Acceptance Condition may not be reduced such as to have the effect of reducing
the 90% threshold specified in Condition (b) to an amount which is 50% or less.
 
    10.  LOST, DESTROYED OR STOLEN ADRS.  If any Unionamerica ADRs representing
Unionamerica ADSs have been lost, destroyed or stolen, the holder should
promptly notify the Exchange Agent by checking the box immediately preceding
"Special Exchange Instructions" and indicate the number of Unionamerica ADSs
represented by the lost, destroyed or stolen Unionamerica ADRs. The holder will
then be instructed as to the steps which must be taken in order to replace the
Unionamerica ADRs. This Letter of Transmittal and related documents cannot be
processed until the holder complies with procedures for replacing lost,
destroyed or stolen Unionamerica ADRs.
 
                                       10
<PAGE>
    11.  SUBSTITUTE FORM W-9 AND FORM W-8.  Under the United States federal
income tax backup withholding rules, unless an exemption applies under the
applicable law and regulations, 31% of the gross cash proceeds payable to a
shareholder or other payee in lieu of its entitlement to fractional shares
pursuant to the Offer must be withheld and remitted to the United States
Treasury, unless the shareholder or other payee provides such person's taxpayer
identification number (employer identification number or social security number)
to the Exchange Agent and certifies that such number is correct. Therefore, each
tendering shareholder should complete and sign the Substitute Form W-9 included
as part of the Letter of Transmittal so as to provide the information and
certification necessary to avoid backup withholding, unless such shareholder
otherwise establishes to the satisfaction of the Exchange Agent that it is not
subject to backup withholding. Certain shareholders (including, among others,
all corporations) are not subject to these backup withholding and reporting
requirements. In order for a non-U.S. shareholder to qualify as an exempt
recipient, that shareholder must submit an IRS Form W-8 or a Substitute Form
W-8, signed under penalties of perjury, attesting to that shareholder's exempt
status. Such statements may be obtained from the Exchange Agent. Backup
withholding is not an additional federal income tax. Rather, the federal income
tax liability of a person subject to backup withholding will be reduced by the
amount of tax withheld. If withholding results in an overpayment of taxes, a
refund may be obtained from the IRS.
 
                                       11
<PAGE>
                      THE EXCHANGE AGENT IN THE OFFER IS:
                    CHASEMELLON SHAREHOLDER SERVICES L.L.C.
                                 P.O. BOX 3300
                           SOUTH HACKENSACK, NJ 07606
                                 1-800-777-3674
                     THE INFORMATION AGENT IN THE OFFER IS:
                    CHASEMELLON SHAREHOLDER SERVICES L.L.C.
                             450 WEST 33(RD) STREET
                               NEW YORK, NY 10001
                                 1-800-549-9249
                      THE DEALER MANAGER IN THE OFFER IS:
                               SMITH BARNEY INC.
                              388 GREENWICH STREET
                               NEW YORK, NY 10013
                                 1-212-816-8541
 
                                       12
<PAGE>
                      TO BE COMPLETED BY U.S. HOLDER ONLY
 
<TABLE>
<S>                       <C>                             <C>
                   PAYER'S NAME: CHASEMELLON SHAREHOLDER SERVICES L.L.C.
 SUBSTITUTE               PART I: PLEASE PROVIDE               Social Security Number
 FORM W-9                 YOUR TIN IN THE BOX AT                         or
                          RIGHT AND CERTIFY BY             Employer Identification Number
                          SIGNING AND DATING                    ---------------------
                          BELOW
 PAYER'S REQUEST FOR      PART 2:    For Payees exempt from backup withholding, see the
 TAXPAYER IDENTIFICATION             enclosed Guidelines for Certification of Taxpayer
 NUMBER (TIN)                        Identification Number on Substitute Form W-9 and
                                     complete as instructed therein.
                          PART 3:    Awaiting TIN  / /
                          CERTIFICATION--Under the penalties of perjury, I certify that (i)
                          the number shown on this form is my correct Taxpayer
                          Identification Number (or I am waiting for a number to be issued
                          to me) and either (a) I have mailed or delivered an application
                          to receive a Taxpayer Identification Number to the appropriate
                          IRS center or Social Security Administration office or (b) I
                          intend to mail or deliver an application in the near future) and
                          (ii) I am not subject to backup withholding because: (a) I am
                          exempt from backup withholding; or (b) I have not been notified
                          by the IRS that I am subject to backup withholding as a result of
                          a failure to report all interest or dividends; or (c) the IRS has
                          notified me that I am no longer subject to backup withholding as
                          a result that I am no longer subject to backup withholding.
                          Certification instructions--You must cross out Item (ii) above if
                          you have been notified by the IRS that you are currently subject
                          to backup withholding because of underreporting interest or
                          dividends on your tax return.
                          SIGNATURE  DATE
 
                          NAME (Please Print)
 
                          ADDRESS (Include Zip/Post Code)
 
</TABLE>
 
                                       13
<PAGE>
        GUIDELINES FOR CERTIFICATION OF TAXPAYER NAME AND IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
 
    GUIDELINES FOR DETERMINING THE PROPER NAME AND IDENTIFICATION NUMBER TO GIVE
THE PAYER.--Social Security numbers have nine digits separated by two hyphens:
i.e., 000-00-0000. Employer identification numbers have nine digits separated by
only one hyphen: i.e., 00-0000000. The table below will help determine the name
and identification number to give the payer.
<TABLE>
<CAPTION>
- -----------------------------------------------------
FOR THIS TYPE OF ACCOUNT:        GIVE THE NAME AND
                                 SOCIAL SECURITY
                                 NUMBER OF--
- -----------------------------------------------------
<S>        <C>                   <C>
1.         An individual's       The individual
           account
2.         Two or more           The actual owner of
           individuals (joint    the account or, if
           account)              combined funds, any
                                 one of the
                                 individuals(1)
3.         Husband and wife      The actual owner of
           (joint account)       the account or, if
                                 joint funds, either
                                 person(1)
4.         Custodian account of  The minor(2)
           a minor (Uniform
           Gift to Minors Act)
5.         Adult and minor       The adult or, if the
           (joint account)       minor is the only
                                 contributor, the
                                 minor(1)
6.         Account in the name   The ward, minor, or
           of guardian or        incompetent
           committee for a       person(3)
           designated ward,
           minor, or
           incompetent person
7.         a. The usual          The
           revocable savings     grantor-trustee(1)
              trust account
              (grantor is also
              trustee)
           b. So-called trust
           account that is not   The actual owner(1)
              a legal or valid
              trust under State
              law
8.         Sole proprietorship   The owner(4)
           account
- -----------------------------------------------------
 
<CAPTION>
FOR THIS TYPE OF ACCOUNT:        GIVE THE NAME AND
                                 EMPLOYER
                                 IDENTIFICATION
                                 NUMBER OF--
<S>        <C>                   <C>
- -----------------------------------------------------
 9.        A valid trust,        The legal entity.
           estate, or pension    (Do not furnish the
           trust                 identifying number
                                 of the personal
                                 representative or
                                 trustee unless the
                                 legal entity itself
                                 is not designated in
                                 the account
                                 title.)(5)
10.        Corporate account     The corporation
11.        Religious,            The organization
           charitable, or
           educational
           organization account
12.        Partnership account   The partnership
           held in the name of
           the business
13.        Association, club,    The organization
           or other tax-exempt
           organization
14.        A broker or           The broker or
           registered nominee    nominee
15.        Account with the      The public entity
           Department of
           Agriculture in the
           name of a public
           entity (such as a
           State or local
           government, school
           district, or prison)
           that receives
           agricultural program
           payments
</TABLE>
 
- ---------------------------------------------------------
- ---------------------------------------------------------
 
(1) List first and circle the name of the person whose number you furnish. If
    only one of the persons has a social security number, that person's number
    must be furnished.
(2) Circle the minor's name and furnish the minor's social security number.
(3) Circle the ward's, minor's or incompetent person's name and furnish such
    person's social security number.
(4) Show the name of the owner.
(5) List first and circle the name of the legal trust, estate, or pension trust.
 
NOTE: If no name is circled when there is more than one name, the number will be
      considered to be that of the first name listed.
 
                                       14
<PAGE>
            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
                                     PAGE 2
 
OBTAINING A NUMBER
 
If you don't have a Taxpayer Identification Number or you do not know your
number, obtain Form SS-5, Application for a Social Security Number Card, or Form
SS-4, Application for Employer Identification Number, at the local office of the
Social Security Administration or the Internal Revenue Service and apply for a
number.
 
PAYEES EXEMPT FROM BACKUP WITHHOLDING
 
Payees specifically exempted from backup withholding on ALL payments include the
following:
 
    - A corporation.
 
    - A financial institution.
 
    - An organization exempt from tax under section 501(a), or an individual
      retirement plan.
 
    - The United States or any agency or instrumentality thereof.
 
    - A State, the District of Columbia, a possession of the United States, or
      any subdivision or instrumentality thereof.
 
    - A foreign government, a political subdivision of a foreign government, or
      any agency or instrumentality thereof.
 
    - An international organization or any agency, or instrumentality thereof.
 
    - A dealer in securities or commodities required to register in the U.S.,
      the District of Columbia or a possession of the U.S.
 
    - A real estate investment trust.
 
    - A common trust fund operated by a bank under section 584(a).
 
    - An exempt charitable remainder trust, or a non-exempt trust described in
      section 4947(a)(1).
 
    - An entity registered at all times under the Investment Company Act of
      1940.
 
    - A foreign central bank of issue.
 
    - Custodial accounts under section 403(a)(7), (b)(7) if the account
      satisfies the requirements of section 401(f)(2).
 
Payments of dividends and patronage dividends not generally subject to backup
withholding include the following:
 
    - Payments to nonresident aliens subject to withholding under section 1441.
 
    - Payments to partnerships not engaged in a trade or business in the U.S.
      and which have at least one non-resident partner.
 
    - Payments of patronage dividends where the amount received is not paid in
      money.
 
    - Payments made by certain foreign organizations.
 
    - Payments made to a nominee.
 
Payments of interest not generally subject to backup withholding include the
following:
 
    - Payments of interest on obligations issued by individuals.
      Note: You may be subject to backup withholding if this interest is $600 or
    more and is paid in the course of the payer's trade or business and you have
    not provided your correct Taxpayer Identification Number to the payer.
 
    - Payments of tax-exempt interest (including exempt-interest dividends under
      section 852).
 
    - Payments described in section 6049(b)(5) to non-resident aliens.
 
    - Payments on tax-free covenant bonds under section 1451.
 
    - Payments made by certain foreign organizations.
 
    - Payments made to a nominee.
 
Exempt payees described above should file Form W-9 to avoid possible erroneous
backup withholding. FILE THIS FORM WITH THE PAYER, FURNISH YOUR TAXPAYER
IDENTIFICATION NUMBER, WRITE "EXEMPT" ON THE FACE OF THE FORM, AND RETURN IT TO
THE PAYER. IF THE PAYMENTS ARE INTEREST, DIVIDENDS, OR PATRONAGE DIVIDENDS, ALSO
SIGN AND DATE THE FORM.
 
Certain payments that are not subject to information reporting are also not
subject to backup withholding. For details, see the regulations under sections
6041, 6041(a), 6042, 6044, 6045, 6049, and 6050A.
 
PRIVACY ACT NOTICE.--Section 6109 requires most recipients of dividend,
interest, or other payments to give taxpayer identification numbers to payers
who must report the payments to IRS. IRS uses the numbers for identification
purposes. Payers must be given the numbers whether or not recipients are
required to file tax returns. Payers must generally withhold 31% of taxable
interest, dividend, and certain other payments to a payee who does not furnish a
taxpayer identification number to a payer. Certain penalties may also apply.
 
PENALTIES.
 
(1) PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER.--If you fail
to furnish your taxpayer identification number to a payer, you are subject to a
penalty of $50 for each such failure unless your failure is due to reasonable
cause and not to willful neglect.
 
(2) CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING.--If you
make a false statement with no reasonable basis which results in no imposition
of backup withholding, you are subject to a penalty of $500.
 
(3) CRIMINAL PENALTY FOR FALSIFYING INFORMATION.--Falsifying certifications or
affirmations may subject you to criminal penalties including fines and/or
imprisonment.
 
FOR ADDITIONAL INFORMATION, CONTACT YOUR TAX CONSULTANT OR THE INTERNAL REVENUE
SERVICE.
 
                                       15

<PAGE>
THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION. If you are in
any doubt about what action to take in connection with the Offer, you should
immediately consult your stockbroker, bank manager, attorney or accountant or an
independent financial advisor authorized under the United Kingdom Financial
Services Act 1986.
 
If you have sold or otherwise transferred any or all of your Unionamerica ADSs,
please forward this document with the accompanying Prospectus, Letter of
Transmittal, reply-paid envelope and other enclosures as soon as possible to the
purchaser or other transferee, or to the agent through whom the sale or transfer
was effected for transmission to the purchaser or other transferee. However,
such documents should not be forwarded to or transmitted in or into Australia or
Japan or to a resident of Australia or Japan.
 
                         NOTICE OF GUARANTEED DELIVERY
                                      FOR
      OFFER TO EXCHANGE EACH OF THE OUTSTANDING AMERICAN DEPOSITARY SHARES
                 EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS AND
                          REPRESENTING ORDINARY SHARES
                                       OF
                           UNIONAMERICA HOLDINGS PLC
                       FOR 0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
 
    THE FOLLOWING PROCEDURES ARE AVAILABLE TO HOLDERS OF AMERICAN DEPOSITARY
SHARES, EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS, EACH REPRESENTING ONE
ORDINARY SHARE, NOMINAL VALUE $0.0448 PER SHARE (THE "UNIONAMERICA ADSS"), OF
UNIONAMERICA HOLDINGS PLC, A CORPORATION REGISTERED IN ENGLAND AND WALES UNDER
THE COMPANIES ACT 1985 OF GREAT BRITAIN, AS AMENDED, WITH REGISTERED NUMBER
2822469 ("UNIONAMERICA").
 
    This form, or one substantially equivalent hereto, must be used to accept
the Offer (as defined in the Offer to Exchange/Prospectus, dated November 5,
1997 (the "Prospectus")) by MMI Companies, Inc., a Delaware corporation ("MMI"),
for Unionamerica ADSs, all as described in the Prospectus if (i) American
Depositary Receipts evidencing Unionamerica ADSs (the "Unionamerica ADRs") are
not immediately available, (ii) time will not permit documents to reach
ChaseMellon Shareholder Services L.L.C., as Exchange Agent (the "Exchange
Agent"), prior to the Expiration Date (as defined in Appendix G to the
Prospectus--"Key Definitions"), or (iii) if the procedures for delivery by
book-entry transfer cannot be completed on a timely basis. This form may be
delivered by hand or mail to the Exchange Agent and must include a guarantee by
an Eligible Institution (as defined in the Prospectus). See "THE
OFFER--Procedures for Tendering Unionamerica ADSs--Guaranteed Delivery
Procedures" of the Prospectus. Capitalized terms and certain other terms used in
this Notice of Guaranteed Delivery and not otherwise defined herein shall have
the respective meanings assigned to them in the Prospectus.
 
                      THE EXCHANGE AGENT FOR THE OFFER IS:
                    CHASEMELLON SHAREHOLDER SERVICES L.L.C.
 
<TABLE>
<S>                          <C>                          <C>
         BY MAIL:                    BY COURIER:               BY HAND DELIVERY:
       P.O. Box 3301             85 Challenger Road         ChaseMellon Shareholder
                                                                    Services
   Attn: Reorganization         Attn: Reorganization        120 Broadway, 13th Floor
        Department                   Department
South Hackensack, NJ 07606    Ridgefield Park, NJ 07660        New York, NY 10271
</TABLE>
 
    Delivery of this Notice of Guaranteed Delivery to an address other than as
set forth above will not constitute a valid delivery.
 
    This form is not to be used to guarantee signatures. If a signature on a
Letter of Transmittal is required to be guaranteed by an "Eligible Institution"
under the instruction thereto, such signature guarantee must appear in the
applicable space provided in the signature box on the Letter of Transmittal.
 
    Unionamerica ADSs may not be tendered pursuant to the Guaranteed Delivery
Procedures.
<PAGE>
Ladies and Gentlemen:
 
    The undersigned hereby tenders to MMI, upon the terms and subject to the
conditions set forth in the Prospectus and the related Letter of Transmittal,
receipt of each of which is hereby acknowledged, the number of Unionamerica ADSs
specified below pursuant to the guaranteed delivery procedures described in "THE
OFFER--Procedures for Tendering Unionamerica ADSs--Guaranteed Delivery
Procedures" of the Prospectus.
 
    The undersigned understands and agrees that the receipt of a Notice of
Guaranteed Delivery will not be treated as a valid acceptance for the purpose of
satisfying the requirement of the City Code (contained in the Minimum Acceptance
Condition) that MMI shall have acquired or agreed to acquire, directly or
indirectly, pursuant to the Offer or otherwise, Unionamerica Securities carrying
in aggregate more than 50% of the voting rights currently exercisable at general
meetings of Unionamerica. To be counted towards satisfaction of the requirement,
the Unionamerica ADRs evidencing such Unionamerica ADSs must be received by the
Exchange Agent or, if applicable, timely confirmation of a book-entry transfer
of such Unionamerica ADSs into the Exchange Agent's account at a Book-Entry
Transfer Facility must be received by the Exchange Agent together with a duly
executed Letter of Transmittal with any required signature guarantees (or, in
the case of a Book-Entry Transfer, an Agent's Message) and any other required
documents.
 
<TABLE>
<S>                                           <C>
Number of Unionamerica ADSs:                  -------------------------------------------
 
- -------------------------------------------   -------------------------------------------
                                                    Signature(s) of Record Holder(s)
 
Unionamerica ADR Nos.
  for Unionamerica ADSs
  (if available):
 
- -------------------------------------------   Dated: ------------------------, 1997
 
Check one box if Unionamerica ADSs            Name(s) of Record Holder(s):
  will be delivered by book-entry transfer:
 
/ / The Depository Trust Company              -------------------------------------------
 
/ / ChaseMellon Shareholder Services L.L.C.
 
Account Number: -------------------           -------------------------------------------
                                                         (Please Type or Print)
 
                                              -------------------------------------------
                                                               (Address)
 
                                              -------------------------------------------
                                                            (Zip/Post Code)
 
                                              -------------------------------------------
                                                     (Area Code and Telephone No.)
</TABLE>
 
<PAGE>
                                   GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)
 
    The undersigned, a firm which is a financial institution that is a
participant in the Security Transfer Agents Medallion Program, the New York
Stock Exchange Medallion Signature Guarantee Program or the New York Stock
Exchange Medallion Program, guarantees to deliver to the Exchange Agent, at its
address set forth above, Unionamerica ADRs tendered hereby, in proper form for
transfer, or confirmation of book-entry transfer of such Unionamerica ADSs into
the Exchange Agent's account at The Depository Trust Company or ChaseMellon
Shareholder Services L.L.C., in each case with delivery of a Letter of
Transmittal (or facsimile thereof) properly completed and duly executed, and any
other required documents, all within three New York Stock Exchange, Inc. trading
days of the date hereof.
 
<TABLE>
<S>                                           <C>
- -------------------------------------------   -------------------------------------------
               (Name of Firm)                            (Authorized Signature)
 
- -------------------------------------------   -------------------------------------------
                 (Address)                                      (Title)
 
- -------------------------------------------     Name: ---------------------------------
              (Zip/Post Code)                            (Please Type or Print)
 
- -------------------------------------------   Dated: ------------------------, 1997
       (Area Code and Telephone No.)
</TABLE>
 
                   DO NOT SEND CERTIFICATES WITH THIS NOTICE.
                   UNIONAMERICA ADRS SHOULD BE SENT WITH YOUR
                             LETTER OF TRANSMITTAL.

<PAGE>
                               SMITH BARNEY INC.
                              388 GREENWICH STREET
                               NEW YORK, NY 10013
 
                               OFFER TO EXCHANGE
                         0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
             FOR EACH OF THE OUTSTANDING AMERICAN DEPOSITARY SHARES
                  EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS OF
                           UNIONAMERICA HOLDINGS PLC
             REPRESENTING ALL OF THE OUTSTANDING ORDINARY SHARES OF
                           UNIONAMERICA HOLDINGS PLC
    THIS OFFER WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON DECEMBER 5,
1997, UNLESS THE OFFER IS EXTENDED IN ACCORDANCE WITH THE TERMS OF THE
ACQUISITION AGREEMENT BETWEEN MMI COMPANIES, INC. AND UNIONAMERICA HOLDINGS PLC
DATED JUNE 25, 1997 (THE "EXPIRATION DATE"). UNIONAMERICA ADSS WHICH ARE
TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE
EXPIRATION DATE (OTHER THAN THOSE UNIONAMERICA ADSS WHICH ARE TENDERED BY
CERTAIN UNIONAMERICA SECURITYHOLDERS (THE "SELLING STOCKHOLDERS") WHO HAVE
EXECUTED IRREVOCABLE UNDERTAKINGS TO ACCEPT THE OFFER (THE "UNDERTAKINGS")). AT
THE EXPIRATION DATE, INCLUDING ANY EXTENSION THEREOF, AND UPON SATISFACTION OR,
WHERE PERMITTED, WAIVER OF THE CONDITIONS OF THE OFFER, ALL UNIONAMERICA ADSS
VALIDLY TENDERED AND NOT VALIDLY WITHDRAWN WILL BE EXCHANGED.
 
                                                                November 6, 1997
 
To Brokers, Dealers, Commercial Banks,
  Trust Companies and Other Nominees:
 
    We have been appointed by MMI Companies, Inc., a Delaware corporation
("MMI"), to act as Dealer Manager in connection with the offer (the "Offer") by
MMI to exchange 0.836 shares of MMI common stock, par value $0.10 per share (the
"MMI Common Stock"), for each outstanding American Depositary Share (a
"Unionamerica ADS"), each representing one ordinary share, nominal value $0.0448
per share (the "Unionamerica Common Stock"), of Unionamerica Holdings plc, a
corporation registered in England and Wales under the Companies Act 1985 of
Great Britain, as amended (the "Companies Act"), with registered number 2822469
("Unionamerica"), upon the terms and subject to the conditions set forth in the
Offer to Exchange/Prospectus, dated November 5, 1997 (the "Prospectus"), and the
related letter of transmittal (the "Letter of Transmittal"). Each share of MMI
Common Stock issued in connection with the Offer will be accompanied by a right
(a "Right") which will entitle the registered holder thereof to purchase from
MMI a unit consisting of one one-hundredth of a share (a "Unit") of Series B
Junior Participating Preferred Stock of MMI, par value $20.00 per share, at a
purchase price of $75.00 per Unit, subject to adjustment, pursuant to a Rights
Agreement between MMI and ChaseMellon Shareholder Services L.L.C., as Rights
Agent.
 
    Please furnish copies of the enclosed materials to those of your clients for
whose accounts you hold Unionamerica ADSs registered in your name or in the name
of your nominee.
 
    The Offer is being made pursuant to an Acquisition Agreement dated as of
June 25, 1997 by and between MMI and Unionamerica (the "Acquisition Agreement").
MMI's obligation to exchange shares of MMI Common Stock for Unionamerica ADSs
pursuant to the Offer is subject to a number of Conditions
<PAGE>
(as defined in the Prospectus), including (i) the acceptance of the Offer by
holders of at least 90% of the outstanding Unionamerica ADSs; provided, however,
that this 90% level may be reduced by MMI, but only with the prior written
consent of Unionamerica, to a level less than 90% but greater than 50%, (ii)
approval of the issuance of MMI Common Stock by MMI's stockholders, and (iii)
various regulatory approvals in the United Kingdom and in the United States.
 
    Upon consummation of the Offer, and in the event that at least 90% of the
outstanding Unionamerica ADSs are tendered in the Offer, MMI will apply the
provisions of Sections 428 to 430F of the Companies Act to effect a compulsory
acquisition of any remaining outstanding Unionamerica ADSs (the "Compulsory
Acquisition"). Upon consummation of the Offer and the Compulsory Acquisition
(collectively, the "Proposed Acquisition"), Unionamerica will become a
wholly-owned subsidiary of MMI.
 
    Enclosed for your information and use are copies of the following documents:
 
    1.  The Prospectus;
 
    2.  The Letter of Transmittal to be used by holders of Unionamerica ADSs
("Unionamerica Securityholders") in accepting the Offer and tendering
Unionamerica ADSs; facsimile copies of the Letter of Transmittal (with manual
signatures) may be used to tender Unionamerica ADSs;
 
    3.  The Notice of Guaranteed Delivery to be used to accept the Offer for
Unionamerica Securityholders if the American Depositary Receipts evidencing
Unionamerica ADSs (the "Unionamerica ADRs") and all other required documents are
not immediately available or cannot be delivered to ChaseMellon Shareholder
Services L.L.C. (the "Exchange Agent") by the Expiration Date (as defined in the
Prospectus) or if the procedures for book-entry transfer cannot be completed by
the Expiration Date;
 
    4.  A letter which may be sent to your clients for whose accounts you hold
Unionamerica ADSs registered in your name or in the name of your nominee, with
space provided for obtaining such clients' instructions with regard to the
Offer;
 
    5.  A substitute form W-9; and
 
    6.  A return envelope addressed to the Exchange Agent.
 
    WE URGE YOU TO CONTACT YOUR CLIENTS AS PROMPTLY AS POSSIBLE. PLEASE NOTE
THAT WITHDRAWAL RIGHTS FOR THE OFFER EXPIRE AT 12 MIDNIGHT, NEW YORK CITY TIME,
ON DECEMBER 5, 1997, UNLESS THE OFFER IS EXTENDED.
 
    Acceptance of Unionamerica ADSs pursuant to the Offer will be made only
after receipt by the Exchange Agent, prior to the Expiration Date, of a Letter
of Transmittal (or facsimile thereof), properly completed and executed, together
with any other required documents. In order for a Unionamerica Securityholder to
validly tender such Unionamerica ADSs (a) a Letter of Transmittal and other
required documents (including the Unionamerica ADRs) must be delivered as
described in the preceding sentence and (b) in the case of Unionamerica
Securityholders tendering their Unionamerica ADSs pursuant to a book-entry
transfer, an Agent's Message (as defined in the Prospectus) and any other
required documents, must be received by the Exchange Agent, and either
Unionamerica ADRs must be received by the Exchange Agent or be delivered
pursuant to the procedures for book-entry transfer set forth under the caption
"THE OFFER--Procedures for Tendering Unionamerica ADSs--Book-Entry Transfer" and
a confirmation thereof must be received by the Exchange Agent, in each case
prior to the Expiration Date.
 
    Any Unionamerica Securityholder who desires to tender Unionamerica ADSs and
whose Unionamerica ADRs are not immediately available, who cannot deliver such
Unionamerica ADRs and all other required documents to the Exchange Agent prior
to the Expiration Date or who cannot comply with the procedures for book-entry
transfer on a timely basis, may tender such Unionamerica ADSs by following the
procedures for guaranteed delivery set forth in the Prospectus under the caption
"THE OFFER--Procedures for Tendering Unionamerica ADSs--Guaranteed Delivery
Procedures".
 
    MMI will not pay any fees or commissions to any broker, dealer or other
person (other than the Exchange Agent, the Information Agent and the Dealer
Manager, as described in the Prospectus) in connection with the solicitation of
tenders of Unionamerica ADSs pursuant to the Offer. However, MMI
<PAGE>
will reimburse you for customary mailing and handling expenses incurred by you
in forwarding any of the enclosed materials to your clients. MMI will pay or
cause to be paid any stock transfer taxes payable with respect to the transfer
of Unionamerica ADSs to it, except as otherwise provided in Instruction 6 of the
Letter of Transmittal.
 
    If you have any inquiries, or require any additional copies of the enclosed
materials, please contact the Information Agent, ChaseMellon Shareholder
Services L.L.C., at 212-273-8080.
 
                                             Very truly yours,
 
                                             SMITH BARNEY INC.
 
    NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU
OR ANY OTHER PERSON AS THE AGENT OF MMI, UNIONAMERICA, THE DEALER MANAGER, THE
INFORMATION AGENT, THE EXCHANGE AGENT, OR OF ANY AFFILIATE OF ANY OF THEM, OR
AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR TO MAKE ANY STATEMENT
ON BEHALF OF ANY OF THEM IN CONNECTION WITH THE OFFER OTHER THAN THE ENCLOSED
DOCUMENTS AND THE STATEMENTS CONTAINED THEREIN.

<PAGE>
                               OFFER TO EXCHANGE
                         0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
             FOR EACH OF THE OUTSTANDING AMERICAN DEPOSITARY SHARES
                  EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS OF
                           UNIONAMERICA HOLDINGS PLC
             REPRESENTING ALL OF THE OUTSTANDING ORDINARY SHARES OF
                           UNIONAMERICA HOLDINGS PLC
    THIS OFFER WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON DECEMBER 5,
1997, UNLESS THE OFFER IS EXTENDED IN ACCORDANCE WITH THE TERMS OF THE
ACQUISITION AGREEMENT BETWEEN MMI COMPANIES, INC. AND UNIONAMERICA HOLDINGS PLC
DATED JUNE 25, 1997 (THE "EXPIRATION DATE"). UNIONAMERICA ADSS WHICH ARE
TENDERED PURSUANT TO THE OFFER MAY BE WITHDRAWN AT ANY TIME PRIOR TO THE
EXPIRATION DATE (OTHER THAN THOSE UNIONAMERICA ADSS WHICH ARE TENDERED BY
CERTAIN UNIONAMERICA SECURITYHOLDERS (THE "SELLING STOCKHOLDERS") WHO HAVE
EXECUTED IRREVOCABLE UNDERTAKINGS TO ACCEPT THE OFFER (THE "UNDERTAKINGS")). AT
THE EXPIRATION DATE, INCLUDING ANY EXTENSION THEREOF, AND UPON SATISFACTION OR,
WHERE PERMITTED, WAIVER OF THE CONDITIONS OF THE OFFER, ALL UNIONAMERICA ADSS
VALIDLY TENDERED AND NOT VALIDLY WITHDRAWN WILL BE EXCHANGED.
 
To our clients:
 
    Enclosed for your consideration are the Offer to Exchange/Prospectus, dated
November 5, 1997 (the "Prospectus"), and the related Letter of Transmittal (the
"Letter of Transmittal") in connection with the offer (the "Offer") by MMI
Companies, Inc., a Delaware corporation ("MMI"), to exchange 0.836 shares of MMI
common stock, par value $0.10 per share (the "MMI Common Stock"), for each
outstanding American Depositary Share (a "Unionamerica ADS"), each representing
one ordinary share, nominal value $0.0448 per share (the "Unionamerica Common
Stock"), of Unionamerica Holdings plc, a corporation registered in England and
Wales under the Companies Act 1985 of Great Britain, as amended (the "Companies
Act") with registered number 2822469 ("Unionamerica"), upon the terms and
subject to the conditions set forth in the Prospectus and the related Letter of
Transmittal.
 
    We hold Unionamerica ADSs for your account. This material is being forwarded
to you as the beneficial owner of Unionamerica ADSs carried by us in your
account but not registered in your name.
 
    A tender of such Unionamerica ADSs can be made only by us as the holder of
record and pursuant to your instructions. The Letter of Transmittal is furnished
to you for your information only and cannot be used by you to tender
Unionamerica ADSs held by us for your account.
 
    We request instructions as to whether you wish to have us tender on your
behalf any or all of the Unionamerica ADSs held by us for your account, upon the
terms and subject to the conditions set forth in the Offer.
 
    Your attention is called to the following:
 
    1.  MMI is offering to acquire each outstanding Unionamerica ADS in exchange
for shares of MMI Common Stock equal to the Exchange Ratio. The Exchange Ratio
(as defined in the Prospectus) is 0.836 shares of MMI Common Stock for each
Unionamerica ADS.
 
    2.  The Offer is being made for all outstanding Unionamerica ADSs.
 
    3.  Each share of MMI Common Stock issued in connection with the Offer will
be accompanied by a right (a "Right") which will entitle the registered holder
thereof to purchase from MMI a unit consisting of one one-hundredth of a share
(a "Unit") of Series B Junior Participating Preferred Stock of MMI, par
<PAGE>
value $20.00 per share, at a purchase price of $75.00 per Unit, subject to
adjustment, pursuant to a Rights Agreement between MMI and ChaseMellon
Shareholder Services L.L.C., as Rights Agent.
 
    4.  The Offer is being made pursuant to an Acquisition Agreement dated as of
June 25, 1997 by and between MMI and Unionamerica (the "Acquisition Agreement").
 
    5.  MMI's obligation to exchange shares of MMI Common Stock for Unionamerica
ADSs pursuant to the Offer is subject to a number of Conditions (as defined in
the Prospectus), including (i) the acceptance of the Offer by holders of at
least 90% of the outstanding Unionamerica ADSs; provided, however, that this 90%
level may be reduced by MMI, but only with the prior written consent of
Unionamerica, to a level less than 90% but greater than 50%, (ii) approval of
the issuance of MMI Common Stock by MMI's stockholders, and (iii) various
regulatory approvals in the United Kingdom and in the United States.
 
    6.  Upon consummation of the Offer, and in the event that at least 90% of
the outstanding Unionamerica ADSs are tendered in the Offer, MMI will apply the
provisions of Sections 428 to 430F of the Companies Act to effect a compulsory
acquisition of any remaining outstanding Unionamerica ADSs (the "Compulsory
Acquisition"). Upon consummation of the Offer and the Compulsory Acquisition
(collectively, the "Proposed Acquisition"), Unionamerica will become a
wholly-owned subsidiary of MMI.
 
    7.  The Board of Directors of Unionamerica has determined that the Proposed
Acquisition is fair to, and in the best interests of, the holders of outstanding
Unionamerica ADSs (the "Unionamerica Securityholders").
 
    8.  Tendering Unionamerica Securityholders will not be obligated to pay
brokerage fees or commissions, or, except as set forth in Instruction 6 of the
Letter of Transmittal, stock transfer taxes, on the transfer of Unionamerica
ADSs pursuant to the Offer.
 
    If you wish to have us tender any or all of your Unionamerica ADSs, please
so instruct us by completing, executing and returning to us the instruction form
contained in this letter. An envelope in which to return your instructions to us
is enclosed. If you authorize the tender of your Unionamerica ADSs, all such
Unionamerica ADSs will be tendered unless otherwise specified in your
instructions. Your instructions should be forwarded to us as soon as possible,
and in any event no later than November 28, 1997 (unless the Offer is extended),
so that we have ample time to submit a tender on your behalf.
 
    The Offer is made solely by the Prospectus and the related Letter of
Transmittal and is being made to all persons holding Unionamerica ADSs. MMI has
advised us that it is not aware of any jurisdiction where the making of the
Offer is prohibited by administrative or judicial action pursuant to any
statute, law or regulation. If MMI becomes aware of any statute, law or
regulation prohibiting the making of the Offer or the acceptance of Unionamerica
ADSs pursuant thereto, MMI has advised us that it will made a good faith effort
to comply with such statute, law or regulation. If, after such good faith
effort, MMI cannot comply with such statute, law or regulation, the Offer will
not be made to (nor will tenders be accepted from or on behalf of) the
Unionamerica Securityholders in such jurisdiction. In any jurisdiction where the
securities, blue sky or other laws require the Offer to be made by a licensed
broker or dealer, the Offer shall be deemed to be made on behalf of MMI by Smith
Barney Inc. or one or more registered brokers or dealers licensed under the laws
of such jurisdiction.
<PAGE>
                        INSTRUCTIONS WITH RESPECT TO THE
                               OFFER TO EXCHANGE
                         0.836 SHARES OF COMMON STOCK,
                         PAR VALUE $0.10 PER SHARE, OF
                              MMI COMPANIES, INC.
             FOR EACH OF THE OUTSTANDING AMERICAN DEPOSITARY SHARES
                  EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS OF
                           UNIONAMERICA HOLDINGS PLC
             REPRESENTING ALL OF THE OUTSTANDING ORDINARY SHARES OF
                           UNIONAMERICA HOLDINGS PLC
 
    The undersigned acknowledge(s) receipt of your letter and the enclosed Offer
to Exchange/Prospectus, dated November 5, 1997 (the "Prospectus") and the
related Letter of Transmittal (the "Letter of Transmittal") in connection with
the offer (the "Offer") by MMI Companies, Inc., a Delaware corporation ("MMI"),
to exchange 0.836 shares of MMI common stock, par value $0.10 per share (the
"MMI Common Stock"), for each outstanding American Depositary Share (a
"Unionamerica ADS"), each representing one ordinary share, nominal value $0.0448
per share (the "Unionamerica Common Stock"), of Unionamerica Holdings plc, a
corporation registered in England and Wales under the Companies Act 1985 of
Great Britain, as amended, with registered number 2822469 ("Unionamerica"), upon
the terms and subject to the conditions set forth in such Prospectus and Letter
of Transmittal.
 
    This will instruct you to tender the number of Unionamerica ADSs indicated
below (or, if no number is indicated below, all Unionamerica ADSs) that are held
by you for the account of the undersigned, upon the terms and subject to the
conditions set forth in the Prospectus and the related Letter of Transmittal.
 
<TABLE>
<S>                                           <C>
Number of Unionamerica ADSs Tendered*         SIGN HERE
 
- ------------------------ Unionamerica ADSs    -------------------------------------------
 
Account Number: ------------------------
 
*Unless otherwise indicated, it will be       -------------------------------------------
assumed that all Unionamerica ADSs held by    (Signature(s))
us for your account are to be tendered.
 
                                              -------------------------------------------
 
Dated:           , 1997                       -------------------------------------------
                                              (Please type or print name(s))
 
                                              -------------------------------------------
 
                                              -------------------------------------------
                                              (Please type or print address)
 
                                              -------------------------------------------
                                              (Area Code and Telephone Number)
 
                                              -------------------------------------------
                                              (Taxpayer Identification or
                                              Social Security Number)
</TABLE>

<PAGE>

                            CERTIFICATE OF FOREIGN STATUS

Form W-8
(Rev. November 1992)
Department of the Treasury
Internal Revenue Service
- --------------------------------------------------------------------------------
PLEASE PRINT OR TYPE

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------------------------------------
<S><C>
    NAME OF OWNER (if joint account, also give joint owner's name.)                   U.S. TAXPAYER IDENTIFICATION NUMBER (if any)
    (See SPECIFIC INSTRUCTIONS.)

    --------------------------------------------------------------------------------------------------------------------------------
    PERMANENT ADDRESS (See SPECIFIC INSTRUCTIONS.)  (Include apt. or suite no.)

    --------------------------------------------------------------------------------------------------------------------------------
    City, province or state, postal code, and country

    --------------------------------------------------------------------------------------------------------------------------------
    CURRENT MAILING ADDRESS, if different from permanent address (include apt. or suite no., or P.O. box if mail is not delivered
     to street address.)

    --------------------------------------------------------------------------------------------------------------------------------
    City, town or post office, state, and ZIP code (if foreign address, enter city, province or state, postal code, and country.)

- ------------------------------------------------------------------------------------------------------------------------------------
List account information           Account number            Account type            Account number            Account type
here (Optional, see
SPECIFIC INSTRUCTIONS.)
- ------------------------------------------------------------------------------------------------------------------------------------
NOTICE OF CHANGE IN STATUS.--To notify the payer, mortgage interest recipient, broker, or barter exchange that you no longer qualify
for exemption, check here . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .    / /
IF YOU CHECK THIS BOX, REPORTING WILL BEGIN ON THE ACCOUNT(S) LISTED.
- ------------------------------------------------------------------------------------------------------------------------------------
PLEASE SIGN HERE
- ------------------------------------------------------------------------------------------------------------------------------------
         CERTIFICATION.--(Check applicable box(es)).  Under penalties of perjury, I certify that:
         / /  For INTEREST PAYMENTS, I am not a U.S. citizen or resident (or I am filing for a foreign corporation, partnership,
              estate, or trust).
         / /  For DIVIDENDS, I am not a U.S. citizen or resident (or I am filing for a foreign corporation, partnership, estate, or
              trust).
         / /  For BROKER TRANSACTIONS or BARTER EXCHANGES, I am an exempt foreign person as defined in the instructions below.

              ---------------------------------------------------------------------------------------------------------------------
              Signature                                                                            Date
- ------------------------------------------------------------------------------------------------------------------------------------
</TABLE>

GENERAL INSTRUCTIONS

(SECTION REFERENCES ARE TO THE INTERNAL REVENUE CODE UNLESS OTHERWISE NOTED.)

PURPOSE

Use Form W-8 or a substitute form containing a substantially similar statement
to tell the payer, mortgage interest recipient, middleman, broker, or barter
exchange that you are a nonresident alien individual, foreign entity, or exempt
foreign person not subject to certain U.S. information return reporting or
backup withholding rules.

CAUTION:  FORM W-8 DOES NOT EXEMPT THE PAYEE FROM THE 30% (OR LOWER TREATY)
NONRESIDENT WITHHOLDING RATES.

NONRESIDENT ALIEN INDIVIDUAL

For income tax purposes, "nonresident alien individual" means an individual who
is neither a U.S. citizen nor resident.  Generally, an alien is considered to be
a U.S. resident if:

- -  The individual was a lawful permanent resident of the United States at any
time during the calendar year, that is, the alien held an immigrant visa (a
"green card"), or

- -  The individual was physically present in the United States on:
   (1)  at least 31 days during the calendar year, and
   (2)  183 days or more during the current year and the 2 preceding calendar
        years (counting all the days of physical presence in the current year,
        one-third the number of days of presence in the first preceding year,
        and only one-sixth of the number of days in the second preceding
        year).

   See PUB. 519, U.S. Tax Guide for Aliens, for more information on resident and
nonresident alien status.

NOTE:  IF YOU ARE A NONRESIDENT ALIEN INDIVIDUAL MARRIED TO A U.S. CITIZEN OR
RESIDENT AND HAVE MADE AN ELECTION UNDER SECTION 6013(g) OR (h), YOU ARE TREATED
AS A U.S. RESIDENT AND MAY NOT use Form W-8.

EXEMPT FOREIGN PERSON

For purposes of this form, you are an "exempt foreign person" for a calendar
year in which:
   1.  You are a nonresident alien individual or a foreign corporation,
partnership, estate, or trust.
   2.  You are an individual who has not been, and plans not to be, present in
the United States for a total of 183 days or more during the calendar year, and
   3.  You are neither engaged, nor plan to be engaged during the year, in a
U.S. trade or business that has effectively connected gains from transactions
with a broker or barter exchange.
   If you do not meet the requirements of 2 or 3 above, you may instead certify
on FORM 1001, Ownership, Exemption, or Reduced Rate Certificate, that your
country has a tax treaty with the United States that exempts your transactions
from U.S. tax.

FILING INSTRUCTIONS

WHEN TO FILE.-File Form W-8 or substitute form before a payment is made. 
Otherwise, the payer may have to withhold and send part of the payment to the
Internal Revenue Service (see BACKUP WITHHOLDING below).  This certificate
generally remains in effect for three calendar years.  However, the payer may
require you to file a new certificate each time a payment is made to you.

WHERE TO FILE.-File this form with the payer of the qualifying income who is the
withholding agent (see WITHHOLDING AGENT on page 2).  Keep a copy for your own
records.

BACKUP WITHHOLDING

A U.S. taxpayer identification number or Form W-8 or substitute form must be
given to the payers of certain income.  If a taxpayer identification number or
Form W-8 or substitute form is not provided or the wrong taxpayer identification
number is provided, these payers may have to withhold 20% of each payment or
transaction.  This is called backup withholding.

NOTE:  ON JANUARY 1, 1993, THE BACKUP WITHHOLDING RATE INCREASES FROM 20% TO
31%.

  Reportable payments subject to backup withholding rules are:
- - Interest payments under section 6049(a).
- - Dividend payments under sections 6042(a) and 6044.
- - Other payments (i.e., royalties and payments from brokers and barter 
exchanges) under sections 6041, 6041A(a), 6045, 6050A, and 6050N.

  If backup withholding occurs, an exempt foreign person who is a nonresident
alien individual may get a refund by filing FORM 1040NR, U.S. Nonresident Alien
Income Tax Return, with the Internal Revenue

                                                            (CONTINUED ON BACK)
- -------------------------------------------------------------------------------
                            Cat. No. 10230M               Form W-8 (REV. 11-92)

<PAGE>


Form W-8 (Rev. 11-92)                                                     Page 2
- --------------------------------------------------------------------------------
Service Center, Philadelphia, PA 19255, even if filing the return is not
otherwise required.

U.S. TAXPAYER IDENTIFICATION NUMBER

The Internal Revenue law requires that certain income be reported to the 
Internal Revenue Service using a U.S. taxpayer identification number (TIN). 
This number can be a social security number assigned to individuals by the 
the Social Security Administration or an employer identification number 
assigned to businesses and other entities by the Internal Revenue Service.

    Payments to account holders who are foreign persons (nonresident alien
individuals, foreign corporations, partnerships, estates, or trusts) generally
are not subject to U.S. reporting requirements.  Also, foreign persons are not
generally required to have a TIN, nor are they subject to any backup withholding
because they do not furnish a TIN to a payer or broker.

    However, foreign persons with income effectively connected with a trade or
business in the United States (income subject to regular (graduated) income
tax), must have a TIN.  To apply for a TIN, use FORM SS-4, Application for
Employer Identification Number, available from local Internal Revenue Service
offices, or FORM SS-5, Application for a Social Security Card, available from
local Social Security Administration offices.

SPECIAL RULES

MORTGAGE INTEREST. --For purposes of the reporting rules, mortgage interest is
interest paid on a mortgage to a person engaged in a trade or business
originating mortgages in the course of that trade or business.  A mortgage
interest recipient is one who receives interest on a mortgage that was acquired
in the course of a trade or business.

    Mortgage interest is not subject to backup withholding rules, but is
subject to reporting requirements under section 6050H.  Generally, however, the
reporting requirements do not apply if the payer of record is a nonresident
alien individual who pays interest on a mortgage not secured by real property in
the United States.  Use Form W-8 or substitute form to notify the mortgage
interest recipient that the payer is a nonresident alien individual.

PORTFOLIO INTEREST. --Generally, portfolio interest paid to a nonresident alien
individual or foreign partnership, estate, or trust is not subject to backup
withholding rules.  However, if interest is paid on portfolio investments to a
beneficial owner that is neither a financial institution nor a member of a
clearing organization, Form W-8 or substitute form is required.

    REGISTERED OBLIGATIONS NOT TARGETED TO FOREIGN MARKETS qualify as portfolio
interest not subject to 30% withholding, but require the filing of Form W-8 or
substitute form.  See INSTRUCTIONS TO WITHHOLDING AGENTS on this page for
reporting rules.

    See PUB. 515, Withholding of Tax on Nonresident Aliens and Foreign
Corporations, for REGISTERED OBLIGATIONS TARGETED TO FOREIGN MARKETS and when
Form W-8 or substitute form is not required on these payments.

    BEARER OBLIGATIONS. --The interest from bearer obligations targeted to
foreign markets is treated as portfolio interest and is not subject to 30%
withholding.  Form W-8 or substitute form is not required.

DIVIDENDS. --Any distribution or payment of dividends by a U.S. corporation sent
to a foreign address is subject to the 30% (or lower treaty) withholding rate,
but is not subject to backup withholding.  Also, there is no backup withholding
on dividend payments made to a foreign person by a foreign corporation. 
However, the 30% withholding (or lower treaty) rate applies to dividend payments
made to a foreign person by a foreign corporation if:

- -   25% or more of the foreign corporation's gross income for the three
preceding taxable years was effectively connected with a U.S. trade or business,
and

- -   The corporation was not subject to the branch profits tax because of an
income tax treaty (see section 884e)).

    If a foreign corporation makes payments to another foreign corporation, the
recipient must be a qualified resident of its country of residence to benefit
from that country's tax treaty.

BROKER OR BARTER EXCHANGES. --Income from transactions with a broker or barter
exchanges is subject to reporting rules and backup withholding unless Form W-8
or substitute form is filed to notify the broker or barter exchange that you are
an exempt foreign person as defined on page 1.

SPECIFIC INSTRUCTIONS

NAME OF OWNER. --If Form W-8 is being filed for portfolio interest, enter the
name of the beneficial owner.

U.S. TAXPAYER IDENTIFICATION NUMBER. --If you have a U.S. taxpayer
identification number, enter your number in this space (see the discussion
earlier).

PERMANENT ADDRESS. --Enter your complete address in the country where you reside
permanently for income tax purposes.

IF YOU ARE:             SHOW THE
                        ADDRESS OF:

An individual           Your permanent
                        residence

A partnership           Principal office
or corporation

An estate or            Permanent residence
trust                   or principal office of
                        any fiduciary

    Also show your current mailing address if it differs from your permanent
address.

    ACCOUNT INFORMATION (OPTIONAL). --If you have MORE THAN ONE ACCOUNT
(savings, certificate of deposit, pension, IRA, etc.) with the same payer, list
all account numbers and types on one Form W-8 or substitute form unless your
payer requires you to file a separate certificate for each account.

    If you have MORE THAN ONE PAYER, file a separate Form W-8 with each payer.

SIGNATURE. --If only one foreign person owns the account(s) listed on this form,
that foreign person should sign the Form W-8.

    If each owner of a joint account is a foreign person, EACH should sign a
separate Form W-8.

NOTICE OF CHANGE IN STATUS. --If you become a U.S. citizen or resident after you
have filed Form W-8 or substitute form, or you cease to be an exempt foreign
person, you must notify the payer in writing within 30 days of your change in
status.

    To notify the payer, you may check the box in the space provided on this
form or use the method prescribed by the payer.

    Reporting will then begin on the account(s) listed and backup withholding
may also begin unless you certify to the payer that:

    (1) The U.S. taxpayer identification number you have given is correct, AND

    (2) The Internal Revenue Service has not notified you that you are subject
to backup withholding because you failed to report certain income.

    You may use FORM W-9, Request for Taxpayer Identification Number and
Certification, to make these certifications.

    If an account is no longer active, you do not have to notify a payer of
your change in status unless you also have another account with the same payer
that is still active.

FALSE CERTIFICATE. --If you file a false certificate when you are not entitled
to the exemption from withholding or reporting, you may be subject to fines
and/or imprisonment under U.S. perjury laws.

INSTRUCTIONS TO WITHHOLDING AGENTS

WITHHOLDING AGENT.--Generally, the person responsible for payment of the items
discussed above to a nonresident alien individual or foreign entity is the
withholding agent (see Pub. 515).

RETENTION OF STATEMENT.--Keep Form W-8 or substitute form in your records for at
least four years following the end of the last calendar year during which the
payment is paid or collected.

PORTFOLIO INTEREST.--Although registered obligations NOT targeted to foreign
markets are not subject to 30% withholding, you must file FORM 1042S, Foreign
Person's U.S. Source Income Subject to Withholding, to report the interest
payment.  Both Form 1042S and a copy of Form W-8 or substitute form must be
attached to FORM 1042, Annual Withholding Tax Return for U.S. Source Income of
Foreign Persons.

<PAGE>

                                                                  Exhibit (a)(8)

               RECOMMENDED PROPOSALS MADE TO OPTION HOLDERS UNDER THE
                              UNIONAMERICA HOLDINGS PLC
           UNAPPROVED EXECUTIVE SHARE OPTION SCHEME DATED NOVEMBER 6, 1997


THIS LETTER AND THE ACCOMPANYING DOCUMENTS ARE IMPORTANT AND REQUIRE YOUR
IMMEDIATE ATTENTION.  If you are in any doubt as to the action you should take,
you should seek your own financial advice from your stockbroker, bank manager,
solicitor, accountant or other independent financial advisor authorised under
the Financial Services Act 1986.  Smith Barney Europe, Ltd., which is regulated
by The Securities and Futures Authority Limited in the UK, is acting exclusively
for MMI and no one else in connection with the Offer and the Recommended
Proposals and will not be responsible to anyone other than MMI for providing the
protections afforded to customers of Smith Barney Europe Limited, nor for giving
advice in relation to the Offer or the Recommended Proposals.  Smith Barney
Europe, Ltd. has approved the contents of this letter and the accompanying
acceptance form for the purposes of section 57 of the Financial Services Act
1986.  The Directors of MMI accept responsibility for the information contained
in this letter concerning MMI, the Offer and the Recommended Proposals and the
Directors of Unionamerica accept responsibility for all the information
contained in this letter relating to the Unionamerica Holdings plc 1996
Executive Share Option Scheme and themselves.  To the best of such Directors'
respective knowledge and belief (having taken all reasonable care to ensure that
such is the case), the information contained in this letter for which such
Directors are responsible is in accordance with the facts and does not omit
anything likely to affect the import of such information.

                    ---------------------------------------------

                                 MMI COMPANIES, INC.
                                RECOMMENDED PROPOSALS
                                       MADE TO
                                 OPTION HOLDERS UNDER
                          THE UNIONAMERICA HOLDINGS PLC 1996
                            EXECUTIVE SHARE OPTION SCHEME

                    ---------------------------------------------


YOUR COMPLETED ACCEPTANCE FORM ("ACCEPTANCE FORM") SHOULD BE RECEIVED AS SOON AS
POSSIBLE AND IN ANY EVENT, NOT LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997 BY
TREVOR SMITH, THE COMPANY SECRETARY OF UNIONAMERICA, AT 3 MINSTER COURT, MINCING
LANE, LONDON EC3R 7DD.  THE PROCEDURE FOR ACCEPTANCE IS SET OUT ON PAGES 4 AND 6
OF THIS LETTER AND IN THE ACCOMPANYING ACCEPTANCE FORM.  PLEASE CONTACT TREVOR
SMITH, THE COMPANY SECRETARY OF UNIONAMERICA, IF YOU HAVE ANY QUESTIONS ABOUT
THIS LETTER.

IF YOU TAKE NO ACTION YOUR OPTION IS LIKELY TO LAPSE AND BECOME WORTHLESS.

<PAGE>

Unionamerica Holdings plc                               MMI Companies Inc.
3 Minster Court                                         540 Lake Cook Road
Mincing Lane                                                    Deerfield
London EC3R 7DD                                        Illinois 60015-5290
Registered No. 2822469



                                                               6 November 1997



TO OPTION HOLDERS IN THE UNIONAMERICA HOLDINGS PLC 1996 EXECUTIVE SHARE OPTION
SCHEME ("THE 1996 SCHEME")

Dear Option holder,

RECOMMENDED PROPOSALS BY MMI TO OPTION HOLDERS IN THE 1996 SCHEME FOLLOWING ITS
RECOMMENDED OFFER FOR UNIONAMERICA



<PAGE>


1   INTRODUCTION

As you already know, on 25 June 1997 MMI Companies, Inc. ("MMI") and
Unionamerica Holdings plc ("Unionamerica") announced that they had signed an
Acquisition Agreement, under which MMI would make a share for share offer ("the
Offer") to acquire the whole of the issued share capital of Unionamerica.  The
Offer is recommended for acceptance by the Unionamerica Board.  Full details of
the Offer are set out in the offer to exchange/prospectus dated 5 November 1997
("the Prospectus"), a copy of which is enclosed together with an Acceptance Form
for you to complete if you wish to accept either of the recommended proposals
described below.  Words and expressions defined in the rules of the 1996 Scheme
and the Prospectus have the same meaning in this letter and the Acceptance Form
unless otherwise stated.  This letter should be read in conjunction with the
Prospectus and the Acceptance Form.

The purpose of this letter is to explain the effect of the Offer on your option
granted on __________ ("Option"), and to describe the recommended proposals
("the Recommended Proposals") which MMI is making available to you in respect of
your Option.  The Recommended Proposals have been jointly developed and agreed
by Unionamerica and MMI.  ACCEPTANCE OF THE RECOMMENDED PROPOSALS WILL BE
CONDITIONAL ON THE OFFER BECOMING OR BEING DECLARED UNCONDITIONAL IN ALL
RESPECTS.

2   EFFECT OF THE OFFER ON YOUR OPTION

Your Option becomes exercisable once MMI has obtained control of Unionamerica
i.e. upon the Offer becoming or being declared unconditional in all respects.

However, the Directors of Unionamerica have determined in accordance with the
rules of the 1996 Scheme that your Option will lapse on the expiry of the period
during which MMI can compulsorily acquire Unionamerica Securities from
Unionamerica Securityholders unless you accept either of the Recommended
Proposals or otherwise exercise your Option.  MMI intends to commence the
compulsory acquisition procedure as soon as it is able to do so after the Offer
becomes or has been declared unconditional in all respects.

Special proposals have been formulated so that if you complete and return the
Acceptance Form by the closing date of the Offer you can arrange for your Option
to be exercised before the Offer closes.

If the Offer is closed and you have not exercised your Option by then MMI
intends to amend the

<PAGE>

Articles of Association of Unionamerica, so that if you exercise your Option
before the end of the compulsory acquisition procedure, the Unionamerica
Securities issued will be automatically exchanged for MMI Common Stock in
accordance with the terms of the Offer.

3   THE RECOMMENDED PROPOSALS

3.1 YOU MAY:

(a) EXERCISE YOUR OPTION, IN WHOLE OR PART, CONDITIONAL UPON THE OFFER BECOMING
    OR BEING DECLARED UNCONDITIONAL IN ALL RESPECTS AND ACCEPT THE OFFER IN
    RESPECT OF THE UNIONAMERICA SECURITIES ACQUIRED BY YOU ON EXERCISE OF YOUR
    OPTION; OR

(b) RELEASE YOUR OPTION, IN WHOLE OR IN PART, CONDITIONAL UPON THE OFFER
    BECOMING OR BEING DECLARED UNCONDITIONAL IN ALL RESPECTS IN RETURN FOR THE
    GRANT OF A REPLACEMENT OPTION OVER MMI COMMON STOCK ("THE OPTION ROLL-OVER
    PROPOSAL").

3.2 FACTORS TO CONSIDER BEFORE MAKING AN ELECTION

Your choice may be influenced by whether or not you are restricted from
disposing of Unionamerica Securities or MMI Common Stock after Closing.  There
are different categories of restriction.  You must check into which category you
fall.  Those who are not subject to any restrictions on disposal of Unionamerica
Securities or MMI Common Stock after Closing are listed in category 1 of the
Appendix.  Those who are not subject to any restrictions on disposal of MMI
Common Stock (but who are subject to restrictions on any disposal of
Unionamerica Securities) after Closing are listed in category 2 of the Appendix.
Those who are restricted from disposing of both Unionamerica Securities and MMI
Common Stock during the period commencing 30 days prior to Closing and ending
when the financial results of MMI covering at least 30 days of post-Closing
combined operations of MMI and Unionamerica have been published are listed in
category 3 of the Appendix.  Whichever category you are in, you are able to
accept either of the Recommended Proposals.  However, you should pay particular
attention to paragraph 3.7 below especially if you are a category 3 Option
holder.

3.3 EXERCISE YOUR OPTION AND ACCEPT THE OFFER

The Offer consists of an offer by MMI to acquire each outstanding share of
$0.0448 of Unionamerica Common Stock (including shares represented by
Unionamerica ADSs) in exchange for 0.836 shares of

<PAGE>

MMI Common Stock.  Each share of MMI Common Stock issued in connection with the
Offer will be identical to other MMI Common Stock in issue and in particular
will be accompanied by a right which will entitle the registered holder thereof
to purchase from MMI a unit of Series B Preferred Stock at a purchase price of
$75.00, subject to adjustment, pursuant to a rights agreement referred to in the
Prospectus on page 53 ("the Rights Agreement").  A summary of the Offer is set
out on pages 4 to 16 of the Prospectus.

By completing the Acceptance Form to elect to exercise your Option and accept
the Offer, you are authorising the exercise of your Option as soon as the Offer
becomes or is declared unconditional in all respects, and the immediate
acceptance of the Offer in respect of the Unionamerica Securities you acquire on
exercise of your Option.

3.4 HOW TO EXERCISE YOUR OPTION AND ACCEPT THE OFFER

If you decide to exercise your Option, in whole or in part, and accept the
Offer, conditional upon the Offer becoming or being declared unconditional in
all respects, you should:

- -   complete and sign the Acceptance Form and return it to Trevor Smith, the
    Company Secretary of Unionamerica, so as to arrive no later than 3.00PM ON
    FRIDAY 28 NOVEMBER 1997; and

- -   enclose with the duly completed Acceptance Form a cheque and your option
    certificate.  If you cannot find your option certificate you should contact
    Trevor Smith.  If the Offer is not declared unconditional in all respects
    your cheque will be returned to you within fourteen days of the Offer
    lapsing.

You are particularly advised to refer to the section headed "Delivery of
Consideration" on page 37 of the Prospectus for details of the arrangements
relating to settlement of the consideration due under the Offer.

3.5 OPTION ROLL-OVER PROPOSAL

Conditional on the Offer becoming or being declared unconditional in all
respects, you may accept an offer by MMI to grant you a new option (your "New
Option") over MMI Common Stock in consideration for the release, in whole or in
part, of your Option over Unionamerica Securities ON THE BASIS THAT FOR EACH OF
THE UNIONAMERICA SECURITIES RELEASED UNDER YOUR OPTION, YOU WILL BE

<PAGE>

GRANTED A NEW OPTION OVER 0.836 SHARES OF MMI COMMON STOCK.

Each share of MMI Common Stock issued on exercise of the New Option will be
identical to other shares of MMI Common Stock in issue and, in particular, will
be accompanied by a right which will entitle the registered holder thereof to
purchase from MMI a unit of Series B Preferred Stock at a purchase price of
$75.00, subject to adjustment, pursuant to the Rights Agreement.

IF YOU ACCEPT THE OPTION ROLL-OVER PROPOSAL, YOU SHOULD BE AWARE THAT WHEN YOU
SUBSEQUENTLY WANT TO EXERCISE YOUR NEW OPTION YOU WILL BE ABLE TO USE A CASH-
LESS EXERCISE FACILITY WHICH MMI HAS ARRANGED WITH SMITH BARNEY INC.  MORE
INFORMATION IS AVAILABLE BY TELEPHONING MICHAEL J GALLAGHER OF SMITH BARNEY INC.
ON 001 312 419 3534.

The effect of the grant of a New Option will be as follows:

(i)    save as mentioned below, your rights under the 1996 Scheme will not
       change except that your New Option will be over shares in MMI Common
       Stock.  MMI has agreed that your New Option will be immediately
       exercisable in full;

(ii)   your New Option will be regarded as having been granted on __________.
       However, your Option would have lapsed after ten years from the date of
       grant.  To prevent an income tax charge arising at the date of grant of
       your New Option, the New Option will lapse after seven years from the
       date of grant.  It will therefore be exercisable until the seventh
       anniversary of the date of grant of the New Option subject to the rules
       of the 1996 Scheme;

(iii)  the total price payable on exercise of your New Option in full will be
       not more than it would have been for your Option; and

(iv)   on exercise of your New Option, income tax will be collected through the
       PAYE system (see paragraph 4.3 below).  A special rule will therefore
       apply to your New Option to deal with the collection of income tax.

       On exercise of your New Option, if any company in the MMI group is
       obliged to account for any tax or other similar liability in any
       jurisdiction for which you are liable or which is recoverable from you
       ("the Tax Liability"), no MMI Common Stock shall be issued or
       transferred to you unless you have either:-

<PAGE>

(a)    made a payment to that company of an amount equal to the Tax Liability;
       or

(b)    entered into arrangements with that company to ensure that such a
       payment is made.

EXAMPLE:

AN OPTION HOLDER HAS AN OPTION OVER 19,037 UNIONAMERICA SECURITIES WITH AN
EXERCISE PRICE OF $15.50.  THE TOTAL EXERCISE PRICE PAYABLE ON COMPLETE EXERCISE
OF THE OPTION WOULD HAVE BEEN $295,073.50.  THE TOTAL PRICE PAYABLE ON COMPLETE
EXERCISE OF THE NEW OPTION WILL NOT EXCEED THIS AMOUNT.

THE NEW OPTION WOULD THEREFORE BE GRANTED IN RESPECT OF 15,914 SHARES OF MMI
COMMON STOCK (I.E. 19,037 X 0.836 = 15,914.932).  (THE NUMBER OF SHARES IS
ROUNDED DOWN TO THE NEAREST WHOLE NUMBER OF SHARES, I.E 15,914.)

THIS MEANS THAT THE PRICE PER SHARE OF MMI COMMON STOCK PAYABLE ON EXERCISE OF
THE NEW OPTION WILL BE $18.54 (I.E. $295,073.5 DIVIDED BY 15,914 = $18.541756).
(THE PRICE PER SHARE PAYABLE IS ROUNDED DOWN TO THE NEAREST CENT, I.E $18.54 SO
THAT THE TOTAL PRICE PAYABLE DOES NOT EXCEED $295,073.50.  THEREFORE, THE TOTAL
PRICE PAYABLE ON EXERCISE OF THE NEW OPTION IN FULL WILL BE $295,045.56.)

3.6    HOW TO ACCEPT THE OPTION ROLL-OVER PROPOSAL

If you wish to accept, in whole or in part, the Option Roll-Over Proposal,
conditional upon the Offer becoming or being declared unconditional in all
respects, you should:

- -      carefully complete and sign the enclosed Acceptance Form and return it
       to Trevor Smith, the Company Secretary of Unionamerica SO AS TO ARRIVE
       NO LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997; and

- -      enclose with the duly completed Acceptance Form your option certificate.
       If you cannot find your option certificate you should contact Trevor
       Smith.  If the Offer does not become or is not declared unconditional in
       all respects, your option certificate will be returned to you.

<PAGE>

If you accept the Option Roll-Over Proposal you will receive in due course a new
option certificate specifying the number of shares of MMI Common Stock subject
to your New Option and the exercise price per share of MMI Common Stock.

At the appropriate time, you should contact George Rosic of MMI on 001 847 374
2266 to check that there are no restrictions on exercising your New Option or
disposing of MMI Common Stock acquired by you.

3.7    GENERAL CONSIDERATIONS

You must consider the taxation implications of each Recommended Proposal very
carefully before you decide which Recommended Proposal to accept, particularly
if you would need a loan to pay for any exercise of your Option.  (These are
summarised in more detail in paragraph 4 of this letter.)

If you exercise your Option and accept the Offer the income tax due in respect
of such exercise WILL NOT BE PAYABLE UNTIL __________ WHEREAS INCOME TAX IS
PAYABLE IMMEDIATELY THROUGH OPERATION OF PAYE ON ANY EXERCISE OF YOUR NEW
OPTION.

If you do not need a loan to exercise your Option and you decide to exercise
your Option and accept the Offer you would have to bear the cost of funding the
exercise of your Option until such time as you can sell your resulting MMI
Common Stock.  However, you will not have to pay the income tax until _____
____.  This benefit may outweigh your funding costs if you are a category 1 or
category 2 Option holder because you are not restricted from selling MMI Common
Stock after Closing.

If you are a category 3 Option holder you will need to consider your position
very carefully.  You could if you accept the Option Roll-Over Proposal wait to
exercise your New Option until such time as you were able to sell your resulting
shares in MMI Common Stock, i.e. your funding costs may be lower BUT income tax
would be payable IMMEDIATELY on exercise of your New Option.

3.8    OTHER CHOICES

(a)    EXERCISE YOUR OPTION BUT NOT ACCEPT THE OFFER

If you are in category 1 you may exercise your Option if the Offer becomes or is
declared

<PAGE>

       unconditional in all respects and obtain Unionamerica Securities.
       However, MMI intends to acquire compulsorily such Unionamerica Securities
       when it is able to do so on the same terms as the Offer.

(b)    EXERCISE YOUR OPTION AND SELL SHARES IN THE MARKET

       If you are in category 1 you may exercise your Option at any time if the
       Offer becomes or is declared unconditional and obtain Unionamerica
       Securities.  If Unionamerica ADSs continue to be traded on the NYSE you
       will be free to sell such Unionamerica ADSs.  However, there is no
       guarantee that you will have a market for your shares.

(c)    TAKE NO ACTION

       If you take no action at all you should be aware that your Option will
       lapse at the end of the period during which MMI can compulsorily acquire
       Unionamerica Securities.

IF YOU ARE IN CATEGORY 2 OR CATEGORY 3, YOU ARE REMINDED THAT YOU HAVE GIVEN AN
IRREVOCABLE UNDERTAKING TO MMI TO ACCEPT THE RECOMMENDED PROPOSALS OR TO ALLOW
YOUR OPTION TO LAPSE.

4      TAXATION

4.1    UK TAX CONSEQUENCES OF EXERCISE

If you exercise your Option, you will be chargeable to income tax on the amount
by which the market value of the relevant Unionamerica Securities on the date of
exercise exceeds the subscription monies paid by you.  This charge to income tax
will arise whether or not you sell your Unionamerica Securities or accept the
Offer.

Unionamerica must disclose details of the exercise to the Inland Revenue at the
end of the tax year.  You should also include details in your tax return for
1997/98.

If you receive a self assessment return under the self assessment rules for the
tax year 1997/98 you will have to give details of any option exercise that gives
rise to an income tax liability and/or any chargeable gains.

<PAGE>

If you do not receive a self assessment return but have received income through
the exercise of an option which has not been taxed in full, you are required to
notify the Inland Revenue within six months of the end of the relevant tax year
(that is by the following 5 October).  Tax will either be collected by an
adjustment to your PAYE Code (if the total tax is under L1,000) or by self
assessment (if the total tax is L1,000 or more).  In the latter case you will
normally have to obtain and fill in a tax return.  The self assessment return
includes special pages for share schemes and you should ask the Inland Revenue
to include the share scheme pages when they send you your return.

IF YOU ARE ASKED TO COMPLETE A SELF ASSESSMENT RETURN IN EITHER OF THE ABOVE
CIRCUMSTANCES, TAX MUST BE PAID BY 31 JANUARY IN THE FOLLOWING TAX YEAR (I.E. 31
JANUARY 1999).

An employee who completes a self assessment return for any year may be liable to
make payments on account for the next year.  If you do not expect to have
similar tax liabilities in later tax years (e.g. because you have exercised your
Option and do not have any other options) you should complete Inland Revenue
form SA 303 so that you do not have to make any payments on account of tax
liabilities for later years.

4.2    UK TAX CONSEQUENCES OF ACCEPTING THE OFFER

The receipt of MMI Common Stock for Unionamerica Securities will not be treated
as a disposal for the purposes of capital gains tax.  The MMI Common Stock will
instead be treated as the same asset as the Unionamerica Securities and as
having been acquired at the same time as the Unionamerica Securities.  A charge
to capital gains tax may arise on the eventual disposal of MMI Common Stock
depending on your personal circumstances.

4.3    UK TAX CONSEQUENCES OF THE OPTION ROLL-OVER PROPOSAL

There will be no tax charge on the release of your Option and the grant of your
New Option.

On exercise of your New Option you will be chargeable to income tax on the
amount by which the market value of the relevant MMI Common Stock on the date of
exercise exceeds the subscription monies paid by you.  THIS TAX WILL BE PAID
IMMEDIATELY BY YOUR EMPLOYING COMPANY UNDER THE PAYE TAX WITHHOLDING MECHANISM
(WHEREAS IF YOU EXERCISE YOUR OPTION, PAYE WILL NOT APPLY AND THE INCOME TAX
MUST BE PAID UNDER THE SELF ASSESSMENT RULES DESCRIBED ABOVE).

<PAGE>

You will still have to notify the Inland Revenue of the exercise of your New
Option in accordance with the provisions set out in paragraph 4.1 above even
though you will already have paid income tax under the PAYE withholding
mechanism.

Paragraph 4 of this letter is a guide to the relevant UK taxation law applicable
to UK residents.  It is provided for your use without liability or
responsibility on the part of MMI or Unionamerica.  If you are not resident in
the UK or are uncertain as to your tax position you are advised to consult your
own independent tax advisors as to your individual tax position.

5      RECOMMENDATION

In view of MMI's wish that the executive directors of Unionamerica Insurance
Company Limited commit to the long-term interests of the enlarged MMI group of
companies, the executive directors of Unionamerica Insurance Company Limited
have undertaken to accept the Recommended Proposals or to allow their Options to
lapse.

THE BOARD OF UNIONAMERICA, WHICH HAS BEEN ADVISED BY DONALDSON, LUFKIN &
JENRETTE SECURITIES CORPORATION, CONSIDERS THE RECOMMENDED PROPOSALS TO BE FAIR
AND REASONABLE AND THEREFORE UNANIMOUSLY RECOMMENDS THEM TO OPTION HOLDERS.
REMEMBER IF YOU DO NOTHING YOUR OPTION IS LIKELY TO LAPSE AND BECOME WORTHLESS.

Please contact Trevor Smith, the Company Secretary of Unionamerica if you have
any questions about this letter or the Prospectus.  If you are in any doubt as
to the action you should take, you should seek your own financial advice from
your stockbroker, bank manager, solicitor, accountant or other independent
financial advisor authorised under the Financial Services Act 1986.

COMPLETED ACCEPTANCE FORMS SHOULD BE RECEIVED AS SOON AS POSSIBLE AND IN ANY
EVENT, NOT LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997 BY TREVOR SMITH, THE
COMPANY SECRETARY OF UNIONAMERICA, AT 3 MINSTER COURT, MINCING LANE, LONDON EC3R
7DD.

B. Frederick Becker                         R. A. Spass
Chairman and Chief Executive Officer        Chairman
for and on behalf of MMI                    for and on behalf of Unionamerica

<PAGE>

                                    THE APPENDIX


                                      Category 1










                                      Category 2











                                      Category 3










<PAGE>

                                                                  Exhibit (a)(9)

           ACCEPTANCE FORM FOR USE BY OPTION HOLDERS UNDER THE 1996 SCHEME

THIS ACCEPTANCE FORM IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.  If you
are in any doubt as to the action you should take, you should consult your
stockbroker, bank manager, solicitor, accountant or other independent financial
advisor immediately.  

P J Cooper
Flat 3
24 Hans Road
London SW3 1RW


                ------------------------------------------------------


                                   ACCEPTANCE FORM

                                      FOR USE BY

                                OPTION HOLDERS UNDER 

                                   THE 1996 SCHEME 


                ------------------------------------------------------

    To accept the Recommended Proposals, please read the accompanying
    Prospectus and letter from MMI and Unionamerica carefully and then complete
    this Acceptance Form by following the instructions in each section of the
    Acceptance Form and the guidance notes. 

    Return this Acceptance Form, duly completed and signed together with a
    cheque in respect of the exercise price if you wish to exercise your
    Option, to Trevor Smith, the Company Secretary of Unionamerica at 3 Minster
    Court, Mincing Lane, London EC3R 7DD as soon as possible, but in any event
    so as to arrive NO LATER THAN 3.00 P.M. ON FRIDAY 28 NOVEMBER 1997.

    Please return your option certificate with your Acceptance Form.  (If you
    have lost your option certificate please contact Trevor Smith.)

<PAGE>

SECTION A: ACCEPTANCE OF THE RECOMMENDED PROPOSALS

OPTION DETAILS

You should tick boxes 3, 4, 5 and/or 6 as appropriate.  

<TABLE>
<CAPTION>
 

    1                   2                   3                 4             5               6


<S>                <C>                 <C>                 <C>            <C>            <C>
NO. OF             EXERCISE PRICE      EXERCISE YOUR       ACCEPT THE     EXERCISE       ACCEPT THE
UNIONAMERICA       FOR EACH OF THE     OPTION IN FULL      OPTION         YOUR           OPTION
SECURITIES UNDER   UNIONAMERICA        AND ACCEPT THE      ROLL-OVER      OPTION IN      ROLL-OVER
OPTION             SECURITIES UNDER    OFFER               PROPOSAL       PART AND       PROPOSAL IN
                   OPTION                                  IN FULL        ACCEPT THE     PART*
                                                                          OFFER


</TABLE>


* If you tick boxes 5 or 6, please indicate the number of shares in respect of
which you wish to:

- -   exercise your Option in part                      ....................

- -   accept the Option Roll-Over Proposal in part      ....................

Acceptance of either or both of the Recommended Proposals is conditional on the
Offer becoming or being declared unconditional in all respects. 

<PAGE>

SECTION B

You must sign below if you wish to accept either or both of the Recommended
Proposals and you have ticked either of boxes 3, 4, 5 or 6 above.




Signed .............................   Date............................
         (Option holder)

<PAGE>

                 GUIDANCE NOTES FOR COMPLETING THIS ACCEPTANCE FORM 

PLEASE READ THE ACCOMPANYING LETTER FROM 
MMI AND UNIONAMERICA AND THE RELEVANT 
SECTIONS OF THE PROSPECTUS BEFORE YOU 
COMPLETE THIS ACCEPTANCE FORM.  If you 
wish to exercise your Option please 
remember to enclose your option certificate 
and a cheque when you return your 
Acceptance Form. 

IF YOU DO NOTHING YOUR OPTION MAY LAPSE.

SECTION A: ACCEPTANCE OF THE 
RECOMMENDED PROPOSALS

To accept the Recommended Proposals you 
may either:

(A)    EXERCISE YOUR OPTION OVER 
       UNIONAMERICA SECURITIES, IN WHOLE 
       OR IN PART, ACCEPT THE OFFER AND 
       RECEIVE MMI COMMON STOCK; AND/OR  

(B)    ROLL-OVER YOUR OPTION, IN WHOLE OR 
       IN PART, FOR A NEW OPTION OVER MMI 
       COMMON STOCK.

You should read the terms and conditions 
applying to the Recommended Proposals 
overleaf.  By signing this Acceptance Form 
you agree to be bound by the terms and 
conditions set out overleaf.  

NOTE: IF YOU ACCEPT THE OPTION ROLL-OVER 
PROPOSAL, YOU SHOULD BE AWARE THAT WHEN 
YOU SUBSEQUENTLY WANT TO EXERCISE YOUR NEW 
OPTION YOU WILL BE ABLE TO USE A CASH-LESS 
EXERCISE FACILITY WHICH MMI HAS ARRANGED 
WITH SMITH BARNEY INC.  MORE INFORMATION IS 
AVAILABLE BY TELEPHONING MICHAEL J 
GALLAGHER OF SMITH BARNEY INC. ON 001 312 
419 3534.

SECTION B: YOUR SIGNATURE

Once you have made your choice and 
completed Section A you should sign Section 
B.  PLEASE MAKE SURE YOU RETURN YOUR 
ACCEPTANCE FORM TO TREVOR SMITH TO ARRIVE 
NO LATER THAN 3.00PM ON FRIDAY 28 
NOVEMBER 1997.

You should keep these guidance notes and the 
terms and conditions overleaf for your future 
reference.

<PAGE>

TERMS AND CONDITIONS

1.   BY SIGNING THIS ACCEPTANCE FORM: 

1.1  I acknowledge receipt of the Prospectus and the letter from MMI and
     Unionamerica dated 5 November 1997;

1.2  I hereby warrant that my Option is valid and subsisting;

1.3  I hereby irrevocably authorise and direct Unionamerica or any person
     nominated by Unionamerica to execute any document and do any such thing on
     my behalf as may be necessary or desirable to give effect to any
     acceptance(s) made by me pursuant to Section A of this Acceptance Form;

2.   BY COMPLETING SECTIONS A AND B OF THIS ACCEPTANCE FORM, I AGREE AS
     FOLLOWS:

2.1  EXERCISE MY OPTION AND ACCEPT THE OFFER (IN WHOLE OR IN PART) - BOX 3 AND
     BOX 5, SECTION A

     Conditional upon the Offer becoming or being declared unconditional in all
     respects and immediately prior to Closing, I hereby exercise my Option (in
     whole or in part) in respect of which I have ticked box 3 or box 5 of
     Section A.  I hereby irrevocably authorise Unionamerica or its agent to
     accept the Offer on my behalf in respect of the Unionamerica Securities I
     receive as a result of exercising my Option in respect of which I have
     ticked box 3 or box 5 of Section A.  I hereby authorise and request MMI or
     its agent to send me to my above address at my risk a certificate for the
     MMI Common Stock to which I am entitled.

2.2  ACCEPT THE OPTION ROLL-OVER PROPOSAL (IN WHOLE OR IN PART) - BOX 4 AND BOX
     6, SECTION A

     Conditional upon the Offer becoming or being declared unconditional in all
     respects and immediately prior to Closing, I hereby accept the Option
     Roll-Over Proposal in respect of my Option in respect of which I have
     ticked box 4 or box 6 of Section A.  I hereby authorise MMI or its agent
     to send me at my risk a new option certificate for my New Option over MMI
     Common Stock to my above address.

3    ACCEPTANCE FORMS WHICH ARE WRONGLY COMPLETED

     I agree that MMI reserves the right to accept any Acceptance Form which is
     wrongly completed or which is received after Friday 28 November 1997. 
     Subject to this:

     (a)     if I have completed the Acceptance Form, but not signed it, I
             accept that the Acceptance Form is of no effect;

     (b)     if I have signed the Acceptance Form, but failed to tick any of
             the boxes in Section A, I accept that I will be treated as having
             ticked box 4 of Section A (i.e that I have elected to accept the
             Option Roll-Over Proposal in full); and

     (c)     if I have signed the Acceptance Form and ticked more than one box
             against my Option (other than the boxes in box 5 and box 6), I
             accept that I will be treated as having ticked box 4 of Section A
             (i.e that I have elected to accept the Option Roll-Over Proposal
             in full).

4.   MISCELLANEOUS 

     Accidental omission to despatch this document or the Acceptance Form to,
     or any failure to receive the same by, any person to whom the Recommended
     Proposals are made or should be made, shall not invalidate the Recommended
     Proposals in any way.

     All acceptances of the Recommended Proposals shall be irrevocable.

     Receipt of documents will not be acknowledged.  All documents and
     remittances sent by, or to, you will be sent at your risk.   

<PAGE>
                                                                 Exhibit (a)(10)

               RECOMMENDED PROPOSALS MADE TO OPTION HOLDERS UNDER THE 
                              UNIONAMERICA HOLDINGS PLC 
              1996 EXECUTIVE SHARE OPTION SCHEME DATED NOVEMBER 6, 1997
                                           
                                                                                

THIS LETTER AND THE ACCOMPANYING DOCUMENTS ARE IMPORTANT AND REQUIRE YOUR
IMMEDIATE ATTENTION.  If you are in any doubt as to the action you should take,
you should seek your own financial advice from your stockbroker, bank manager,
solicitor, accountant or other independent financial advisor authorised under
the Financial Services Act 1986.
Smith Barney Europe, Ltd., which is regulated by The Securities and Futures
Authority Limited in the UK, is acting exclusively for MMI and no one else in
connection with the Offer and the Recommended Proposals and will not be
responsible to anyone other than MMI for providing the protections afforded to
customers of Smith Barney Europe Limited, nor for giving advice in relation to
the Offer or the Recommended Proposals.
Smith Barney Europe, Ltd. has approved the contents of this letter and the
accompanying acceptance form for the purposes of section 57 of the Financial
Services Act 1986.
The Directors of MMI accept responsibility for the information contained in this
letter concerning MMI, the Offer and the Recommended Proposals and the Directors
of Unionamerica accept responsibility for all the information contained in this
document relating to the Unionamerica Holdings plc Unapproved Executive Share
Option Scheme and themselves.  To the best of such Directors' respective
knowledge and belief (having taken all reasonable care to ensure that such is
the case), the information contained in this letter for which such Directors are
responsible is in accordance with the facts and does not omit anything likely to
affect the import of such information.

                    ---------------------------------------------

                                 MMI COMPANIES, INC.

                                RECOMMENDED PROPOSALS
                                       MADE TO 
                                 OPTION HOLDERS UNDER
                      THE UNIONAMERICA HOLDINGS PLC UNAPPROVED 
                          EXECUTIVE SHARE OPTION SCHEME     

                 ---------------------------------------------------

YOUR COMPLETED ACCEPTANCE FORM ("ACCEPTANCE FORM") SHOULD BE RECEIVED AS SOON AS
POSSIBLE AND IN ANY EVENT, NOT LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997 BY
TREVOR SMITH, THE COMPANY SECRETARY OF UNIONAMERICA, AT 3 MINSTER COURT, MINCING
LANE, LONDON EC3R 7DD.  THE PROCEDURE FOR ACCEPTANCE IS SET OUT ON PAGES 4 AND 6
OF THIS LETTER AND IN THE ACCOMPANYING ACCEPTANCE FORM.  PLEASE CONTACT TREVOR
SMITH, THE COMPANY SECRETARY OF UNIONAMERICA, IF YOU HAVE ANY QUESTIONS ABOUT
THIS LETTER.

IF YOU TAKE NO ACTION YOUR OPTION IS LIKELY TO LAPSE AND BECOME WORTHLESS.



<PAGE>


Unionamerica Holdings plc              MMI Companies Inc.
3 Minster Court                        540 Lake Cook Road
Mincing Lane                           Deerfield 
London EC3R 7DD                        Illinois 60015-5290
Registered No. 2822469



                                                                 6 November 1997



TO OPTION HOLDERS IN THE UNIONAMERICA HOLDINGS PLC UNAPPROVED EXECUTIVE SHARE
OPTION SCHEME ("THE 1993 SCHEME") 

Dear Option holder,

RECOMMENDED PROPOSALS BY MMI TO OPTION HOLDERS IN THE 1993 SCHEME FOLLOWING ITS 
RECOMMENDED OFFER FOR UNIONAMERICA

<PAGE>

1   INTRODUCTION

As you already know, on 25 June 1997 MMI Companies, Inc. ("MMI") and
Unionamerica Holdings plc ("Unionamerica") announced that they had signed an
Acquisition Agreement, under which MMI would make a share for share offer ("the
Offer") to acquire the whole of the issued share capital of Unionamerica.  The
Offer is recommended for acceptance by the Unionamerica Board.  Full details of
the Offer are set out in the offer to exchange/prospectus dated 5 November 1997
("the Prospectus"), a copy of which is enclosed together with an Acceptance Form
for you to complete if you wish to accept either of the recommended proposals
described below.  Words and expressions defined in the rules of the 1993 Scheme
and the Prospectus have the same meaning in this letter and the Acceptance Form
unless otherwise stated.  This letter should be read in conjunction with the
Prospectus and the Acceptance Form.  
  
The purpose of this letter is to explain the effect of the Offer on your option
granted on __________ ("Option"), and to describe the recommended proposals
("the Recommended Proposals") which MMI is making available to you in respect of
your Option.  The Recommended Proposals have been jointly developed and agreed
by Unionamerica and MMI.  ACCEPTANCE OF THE RECOMMENDED PROPOSALS WILL BE
CONDITIONAL ON THE OFFER BECOMING OR BEING DECLARED UNCONDITIONAL IN ALL
RESPECTS.  

2   EFFECT OF THE OFFER ON YOUR OPTION

You are currently entitled to exercise your Option.  

However, the Directors of Unionamerica have determined in accordance with the
rules of the 1993 Scheme that your Option will lapse on the expiry of the period
during which MMI can compulsorily acquire Unionamerica Securities from
Unionamerica Securityholders unless you accept either of the Recommended
Proposals or otherwise exercise your Option.  MMI intends to commence the
compulsory acquisition procedure as soon as it is able to do so after the Offer
becomes or has been declared unconditional in all respects.

Special proposals have been formulated so that if you complete and return the
Acceptance Form by the closing date of the Offer you can arrange for your Option
to be exercised before the Offer closes.

If the Offer is closed and you have not exercised your Option by then MMI
intends to amend the Articles of Association of Unionamerica, so that if you
exercise your Option before the end of the 

<PAGE>

compulsory acquisition procedure, the Unionamerica Securities issued will be
automatically exchanged for MMI Common Stock in accordance with the terms of the
Offer.

3   THE RECOMMENDED PROPOSALS

3.1 YOU MAY:

(a) EXERCISE YOUR OPTION, IN WHOLE OR IN PART, CONDITIONAL UPON THE OFFER
    BECOMING OR BEING DECLARED UNCONDITIONAL IN ALL RESPECTS AND ACCEPT THE
    OFFER IN RESPECT OF THE UNIONAMERICA SECURITIES ACQUIRED BY YOU ON EXERCISE
    OF YOUR OPTION; OR 

(b) RELEASE YOUR OPTION, IN WHOLE OR IN PART, CONDITIONAL UPON THE OFFER
    BECOMING OR BEING DECLARED UNCONDITIONAL IN ALL RESPECTS IN RETURN FOR THE
    GRANT OF A REPLACEMENT OPTION OVER MMI COMMON STOCK ("THE OPTION ROLL-OVER
    PROPOSAL").

3.2 FACTORS TO CONSIDER BEFORE MAKING AN ELECTION

Your choice may be influenced by whether or not you are restricted from
disposing of Unionamerica Securities or MMI Common Stock after Closing.  There
are different categories of restriction.  You must check into which category you
fall.  Those who are not subject to any restrictions on disposal of Unionamerica
Securities or MMI Common Stock after Closing are listed in category 1 of the
Appendix.  Those who are not subject to any restrictions on disposal of MMI
Common Stock (but who are subject to restrictions on any disposal of
Unionamerica Securities) after Closing are listed in category 2 of the Appendix.
Those who are restricted from disposing of both Unionamerica Securities and MMI
Common Stock during the period commencing 30 days prior to Closing and ending
when the financial results of MMI covering at least 30 days of post-Closing
combined operations of MMI and Unionamerica have been published are listed in
category 3 of the Appendix.  Whichever category you are in, you are able to
accept either of the Recommended Proposals.  However, you should pay particular
attention to paragraph 3.7 below especially if you are a category 3 Option
holder.  

3.3 EXERCISE YOUR OPTION AND ACCEPT THE OFFER

The Offer consists of an offer by MMI to acquire each outstanding share of
$0.0448 of Unionamerica Common Stock (including shares represented by
Unionamerica ADSs) in exchange for 0.836 shares of MMI Common Stock.  Each share
of MMI Common Stock issued in connection with the Offer will be 

<PAGE>

identical to other MMI Common Stock in issue and in particular will be
accompanied by a right which will entitle the registered holder thereof to
purchase from MMI a unit of Series B Preferred Stock at a purchase price of
$75.00, subject to adjustment, pursuant to a rights agreement referred to in the
Prospectus on page 53 ("the Rights Agreement").  A summary of the Offer is set
out on pages 4 to 16  of the Prospectus.

By completing the Acceptance Form to elect to exercise your Option and accept
the Offer, you are authorising the exercise of your Option as soon as the Offer
becomes or is declared unconditional in all respects, and the immediate
acceptance of the Offer in respect of the Unionamerica Securities you acquire on
exercise of your Option.

3.4 HOW TO EXERCISE YOUR OPTION AND ACCEPT THE OFFER

If you decide to exercise your Option, in whole or in part, and accept the
Offer, conditional upon the Offer becoming or being declared unconditional in
all respects, you should:

- -   complete and sign the Acceptance Form and return it to Trevor Smith, the
    Company Secretary of Unionamerica, so as to arrive no later than 3.00PM ON
    FRIDAY 28 NOVEMBER 1997; and  

- -   enclose with the duly completed Acceptance Form a cheque and your option
    certificate.  If you cannot find your option certificate you should contact
    Trevor Smith.  If the Offer is not declared unconditional in all respects
    your cheque will be returned to you within 14 days of the Offer lapsing.

You are particularly advised to refer to the section headed "Delivery of
Consideration" on page 37 of the Prospectus for details of the arrangements
relating to settlement of the consideration due under the Offer. 

3.5 OPTION ROLL-OVER PROPOSAL

Conditional on the Offer becoming or being declared unconditional in all
respects, you may accept an offer by MMI to grant you a new option (your "New
Option") over MMI Common Stock in consideration for the release, in whole or in
part, of your Option over Unionamerica Securities ON THE BASIS THAT FOR EACH OF
THE UNIONAMERICA SECURITIES RELEASED UNDER YOUR OPTION, YOU WILL BE GRANTED A
NEW OPTION OVER 0.836 SHARES OF MMI COMMON STOCK. 

<PAGE>

Each share of MMI Common Stock issued on exercise of the New Option will be
identical to other shares of MMI Common Stock in issue and, in particular, will
be accompanied by a right which will entitle the registered holder thereof to
purchase from MMI a unit of Series B Preferred Stock at a purchase price of
$75.00, subject to adjustment, pursuant to the Rights Agreement. 

IF YOU ACCEPT THE OPTION ROLL-OVER PROPOSAL, YOU SHOULD BE AWARE THAT WHEN YOU
SUBSEQUENTLY WANT TO EXERCISE YOUR NEW OPTION YOU WILL BE ABLE TO USE A
CASH-LESS EXERCISE FACILITY WHICH MMI HAS ARRANGED WITH SMITH BARNEY INC.  MORE
INFORMATION IS AVAILABLE BY TELEPHONING MICHAEL J GALLAGHER OF SMITH BARNEY INC.
ON 001 312 419 3534.

The effect of the grant of a New Option will be as follows: 

(i)   your rights under the 1993 Scheme will not change in any way except that
      your New Option will be over shares in MMI Common Stock.  The rules of
      the 1993 Scheme will continue to apply as they currently apply to your
      Option;  
 
(ii)  your New Option will be regarded as having been granted on __________,
      the date when your Option was granted and will continue to be
      exercisable, subject to the rules of the 1993 Scheme, until the date
      that your Option would have lapsed under the rules of the 1993 Scheme. 
      Your New Option will therefore be exercisable from the time it is
      granted;  

(iii) the total price payable on exercise of your New Option in full will be
      not more than it would have been for your Option; and

(iv)  on exercise of your New Option, income tax will be collected through the
      PAYE system (see paragraph 4.3 below).  A special rule will therefore
      apply to your New Option to deal with the collection of income tax.

      On exercise of your New Option, if any company in the MMI group is
      obliged to account for any tax or other similar liability in any
      jurisdiction for which you are liable or which is recoverable from you
      ("the Tax Liability"), no MMI Common Stock shall be issued or
      transferred to you unless you have either:-

      (a)     made a payment to that company of an amount equal to the Tax
              Liability; or

<PAGE>

      (b)     entered into arrangements with that company to ensure that such a
              payment is made. 

      EXAMPLE:

      AN OPTION HOLDER HAS AN OPTION OVER 21,008 UNIONAMERICA SECURITIES WITH
      AN EXERCISE PRICE OF $4.48.  THE TOTAL EXERCISE PRICE PAYABLE ON
      EXERCISE OF THE OPTION IN FULL WOULD HAVE BEEN $94,115.84.  THE TOTAL
      PRICE PAYABLE ON EXERCISE OF THE NEW OPTION IN FULL WILL NOT EXCEED THIS
      AMOUNT.

      THE NEW OPTION WOULD THEREFORE BE GRANTED IN RESPECT OF 17,562 SHARES IN
      MMI COMMON STOCK (I.E. 21,008 X 0.836 = 17,562.688).  (THE NUMBER OF
      SHARES IS ROUNDED DOWN TO THE NEAREST WHOLE NUMBER OF SHARES, I.E
      17,562.)

      THIS MEANS THAT THE PRICE PER SHARE OF MMI COMMON STOCK PAYABLE ON
      EXERCISE ON THE NEW OPTION WILL BE $5.35 (I.E. $94,115.84 DIVIDED BY
      17,562 = $5.3590616).  (THE PRICE PAYABLE PER SHARE IS ROUNDED DOWN TO
      THE NEAREST CENT, I.E $5.35 SO THAT THE TOTAL PRICE PAYABLE DOES NOT
      EXCEED $94,115.84.  THEREFORE, THE TOTAL PRICE PAYABLE ON EXERCISE IN
      FULL OF THE NEW OPTION WILL BE $93,956.70)

3.6   HOW TO ACCEPT THE OPTION ROLL-OVER PROPOSAL

If you wish to accept, in whole or in part, the Option Roll-Over Proposal
conditional upon the Offer becoming or being declared unconditional in all
respects, you should:

- -     carefully complete and sign the enclosed Acceptance Form and return it
      to Trevor Smith, the Company Secretary of Unionamerica, SO AS TO ARRIVE
      NO LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997; and  

- -     enclose with the duly completed Acceptance Form your option certificate. 
      If you cannot find your option certificate you should contact Trevor
      Smith.  If the Offer does not become or is not declared unconditional in
      all respects, your option certificate will be returned to you.

If you accept the Option Roll-Over Proposal you will receive in due course a new
option certificate 

<PAGE>

specifying the number of shares of MMI Common Stock subject to your New Option
and the exercise price per share of MMI Common Stock.

At the appropriate time, you should contact George Rosic of MMI on 001 847 374
2266 to check that there are no restrictions on exercising your New Option or
disposing of MMI Common Stock acquired by you.

3.7   GENERAL CONSIDERATIONS

You must consider the taxation implications of each Recommended Proposal very
carefully before you decide which Recommended Proposal to accept particularly if
you would need a loan to pay for any exercise of your Option.  (These are
summarised in more detail in paragraph 4 of this letter.)

If you exercise your Option and accept the Offer the income tax due in respect
of such exercise WILL NOT BE PAYABLE UNTIL __________ WHEREAS INCOME TAX IS
PAYABLE IMMEDIATELY THROUGH OPERATION OF PAYE ON ANY EXERCISE OF YOUR NEW
OPTION.

If you do not need a loan to exercise your Option and you decide to exercise
your Option and accept the Offer, you would have to bear the cost of funding the
exercise of your Option until such time as you can sell your resulting MMI
Common Stock.  However, you will not have to pay the income tax due until
__________.  This benefit may outweigh your funding costs if you are a category
1 or category 2 Option holder because you are not restricted from selling MMI
Common Stock after Closing.  

If you are a category 3 Option holder you will need to consider your position
very carefully.  You could if you accept the Option Roll-Over Proposal wait to
exercise your New Option until such time as you were able to sell your resulting
shares of MMI Common Stock, i.e. your funding costs may be lower BUT income tax
would be payable IMMEDIATELY.

<PAGE>

3.8   OTHER CHOICES 

In addition to the Recommended Proposals you may:-

(a)   EXERCISE YOUR OPTION BUT NOT ACCEPT THE OFFER

      If you are in category 1, you may exercise your Option at any time and
      obtain Unionamerica Securities.  However, MMI intends to acquire
      compulsorily such Unionamerica Securities when it is able to do so on
      the same terms as the Offer;  

(b)   EXERCISE YOUR OPTION AND SELL SHARES IN THE MARKET

      If you are in category 1, you may exercise your Option at any time and
      obtain Unionamerica Securities.  If Unionamerica ADSs continue to be
      traded on the NYSE you will be free to sell such Unionamerica ADSs. 
      However, there is no guarantee that you will have a market for your
      shares.

(c)   TAKE NO ACTION   

      If you take no action at all you should be aware that your Option will
      lapse at the end of the period during which Unionamerica Securities can
      be compulsorily acquired by MMI.

IF YOU ARE IN CATEGORY 2 OR CATEGORY 3, YOU ARE REMINDED THAT YOU HAVE GIVEN AN
IRREVOCABLE UNDERTAKING TO MMI TO ACCEPT THE RECOMMENDED PROPOSALS OR TO ALLOW
YOUR OPTION TO LAPSE. 

4     TAXATION

4.1   UK TAX CONSEQUENCES OF EXERCISE

If you exercise your Option, you will be chargeable to income tax on the amount
by which the market value of the relevant Unionamerica Securities on the date of
exercise exceeds the subscription monies paid by you.  This charge to income tax
will arise whether or not you sell your Unionamerica Securities or accept the
Offer.  

Unionamerica must disclose details of the exercise to the Inland Revenue at the
end of the tax year.

<PAGE>

You should also include details in your tax return for 1997/98.

If you receive a self assessment return under the self assessment rules for the
tax year 1997/98 you will have to give details of any option exercise that gives
rise to an income tax liability and/or any chargeable gains.

If you do not receive a self assessment return but have received income through
the exercise of an option which has not been taxed in full, you are required to
notify the Inland Revenue within six months of the end of the relevant tax year
(that is by the following 5 October).  Tax will either be collected by an
adjustment to your PAYE Code (if the total tax is under L1,000) or by self
assessment (if the total tax is L1,000 or more).  In the latter case you will
normally have to obtain and fill in a tax return.  The self assessment return
includes special pages for share schemes and you should ask the Inland Revenue
to include the share scheme pages when they send you your return.  

IF YOU ARE ASKED TO COMPLETE A SELF ASSESSMENT RETURN IN EITHER OF THE ABOVE
CIRCUMSTANCES, TAX MUST BE PAID BY 31 JANUARY IN THE FOLLOWING TAX YEAR (I.E. 31
JANUARY _____).

An employee who completes a self assessment return for any year may be liable to
make payments on account for the next year.  If you do not expect to have
similar tax liabilities in later tax years (e.g. because you have exercised your
Option and do not have any other options) you should complete Inland Revenue
form SA 303 so that you do not have to make any payments on account of tax
liabilities for later years.
 
4.2   UK TAX CONSEQUENCES OF ACCEPTING THE OFFER

The receipt of MMI Common Stock for Unionamerica Securities will not be treated
as a disposal for the purposes of capital gains tax.  The MMI Common Stock will
instead be treated as the same asset as the Unionamerica Securities and as
having been acquired at the same time as the Unionamerica Securities.  A charge
to capital gains tax may arise on the eventual disposal of MMI Common Stock
depending on your personal circumstances.   

4.3   UK TAX CONSEQUENCES OF THE OPTION ROLL-OVER PROPOSAL 

There will be no tax charge on the release of your Option and the grant of your
New Option. 

<PAGE>

On exercise of your New Option you will be chargeable to income tax on the
amount by which the market value of the relevant MMI Common Stock on the date of
exercise exceeds the subscription monies paid by you.  THIS TAX WILL BE PAID
IMMEDIATELY BY YOUR EMPLOYING COMPANY UNDER THE PAYE TAX WITHHOLDING MECHANISM
(WHEREAS IF YOU EXERCISE YOUR OPTION, PAYE WILL NOT APPLY AND THE INCOME TAX
MUST BE PAID UNDER THE SELF ASSESSMENT RULES DESCRIBED ABOVE).  

You will still have to notify the Inland Revenue of the exercise of your New
Option in accordance with the provisions set out in paragraph 4.1 above even
though you will already have paid income tax under the PAYE withholding
mechanism.

Paragraph 4 of this letter is a guide to the relevant UK taxation law applicable
to UK residents.  It is provided for your use without liability or
responsibility on the part of MMI or Unionamerica.  If you are not resident in
the UK or are uncertain as to your tax position you are advised to consult your
own independent tax advisors as to your individual tax position.

5     RECOMMENDATION

In view of MMI's wish that the executive directors of Unionamerica Insurance
Company Limited commit to the long-term interests of the enlarged MMI group of
companies, the executive directors of Unionamerica Insurance Company Limited
have undertaken to accept the Recommended Proposals, or to allow their Options
to lapse.

THE BOARD OF UNIONAMERICA, WHICH HAS BEEN ADVISED BY DONALDSON, LUFKIN &
JENRETTE SECURITIES CORPORATION, CONSIDERS THE RECOMMENDED PROPOSALS TO BE FAIR
AND REASONABLE AND THEREFORE UNANIMOUSLY RECOMMENDS THEM TO OPTION HOLDERS. 
REMEMBER IF YOU DO NOTHING YOUR OPTION IS LIKELY TO LAPSE AND BECOME WORTHLESS.

Please contact Trevor Smith, the Company Secretary of Unionamerica if you have
any questions about this letter or the Prospectus.  If you are in any doubt as
to the action you should take, you should seek your own financial advice from
your stockbroker, bank manager, solicitor, accountant or other independent
financial advisor authorised under the Financial Services Act 1986.

COMPLETED ACCEPTANCE FORMS SHOULD BE RECEIVED AS SOON AS POSSIBLE AND IN ANY
EVENT, NOT LATER THAN 3.00PM ON [5 BUSINESS DAYS BEFORE CLOSING DATE FOR OFFER]
1997 BY TREVOR SMITH, THE COMPANY SECRETARY OF UNIONAMERICA, AT 3 MINSTER COURT,
MINCING LANE, LONDON 

<PAGE>

EC3R 7DD.  

B. Frederick Becker                         R. A. Spass
Chairman and Chief Executive Officer        Chairman 
for and on behalf of MMI                    for and on behalf of Unionamerica



<PAGE>


      THE APPENDIX    

                                      Category 1




                                      Category 2






                                      Category 3








<PAGE>

                                                                 Exhibit (a)(11)
           ACCEPTANCE FORM FOR USE BY OPTION HOLDERS UNDER THE 1993 SCHEME
                                           

THIS ACCEPTANCE FORM IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.  If you
are in any doubt as to the action you should take, you should consult your
stockbroker, bank manager, solicitor, accountant or other independent financial
advisor immediately.  

T P Open
170 Hillbury Road
Warlingham
Surrey CR6 9TE



                ------------------------------------------------------
          

          
                                   ACCEPTANCE FORM
          
                                      FOR USE BY
          
                                OPTION HOLDERS UNDER 
          
                                   THE 1993 SCHEME 
          
                        

                ------------------------------------------------------
          
- -   To accept the Recommended Proposals, please read the accompanying
    Prospectus and letter from MMI and Unionamerica carefully and then complete
    this Acceptance Form by following the instructions in each section of the
    Acceptance Form and the guidance notes. 
                             
- -   Return this Acceptance Form, duly completed and signed together with a
    cheque in respect of the exercise price if you wish to exercise your
    Option, to Trevor Smith, the Company Secretary of Unionamerica at 3 Minster
    Court, Mincing Lane, London EC3R 7DD as soon as possible, but in any event
    so as to arrive NO LATER THAN 3.00 P.M. ON FRIDAY 28 NOVEMBER 1997.
    
- -   Please return your option certificate with your Form.  (If you have lost
    your option certificate please contact Trevor Smith.)


<PAGE>

SECTION A: ACCEPTANCE OF THE RECOMMENDED PROPOSALS
    
OPTION DETAILS
    
You should tick boxes 3, 4, 5 and/or 6 as appropriate.  
    
<TABLE>
<CAPTION>
 
- -----------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------
    1              2                   3                 4              5              6
- -----------------------------------------------------------------------------------------------
<S>           <C>                 <C>                 <C>            <C>            <C>
NO. OF        EXERCISE PRICE      EXERCISE YOUR       ACCEPT THE     EXERCISE       ACCEPT THE     
UNIONAMERICA  FOR EACH OF THE     OPTION IN FULL      OPTION         YOUR           OPTION         
SECURITIES    UNIONAMERICA        AND ACCEPT THE      ROLL-OVER      OPTION IN      ROLL-OVER      
UNDER OPTION  SECURITIES          OFFER               PROPOSAL IN    PART AND       PROPOSAL       
              UNDER OPTION                            FULL           ACCEPT THE     IN PART*       
                                                                     OFFER*         
- -----------------------------------------------------------------------------------------------

- -----------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------
</TABLE>
    
    
* If you tick boxes 5 or 6, please indicate the number of shares in respect of
which you wish to:
    
- -   exercise your Option in part                  .............................
    
- -   accept the Option Roll-Over Proposal in part  .............................
    
    
Acceptance of either or both of the Recommended Proposals is conditional on the
Offer becoming or being declared unconditional in all respects.  
    
<PAGE>

SECTION B
    
You must sign below if you wish to accept either or both of the Recommended
Proposals and you have ticked either of boxes 3, 4, 5 or 6 above. 
    
    
    
    
Signed ..................................................    Date...............
              (Option holder)          
    

<PAGE>

                 GUIDANCE NOTES FOR COMPLETING THIS ACCEPTANCE FORM 

PLEASE READ THE ACCOMPANYING LETTER FROM MMI AND UNIONAMERICA AND THE RELEVANT
SECTIONS OF THE PROSPECTUS BEFORE YOU COMPLETE THIS FORM.  If you wish to
exercise your Option please remember to enclose your option certificate and a
cheque when you return your Acceptance Form.

IF YOU DO NOTHING YOUR OPTION MAY LAPSE.

SECTION A: ACCEPTANCE OF THE RECOMMENDED PROPOSALS

To accept the Recommended Proposals you may either:
 
(a) EXERCISE YOUR OPTION OVER UNIONAMERICA SECURITIES, IN WHOLE OR IN PART,
    ACCEPT THE OFFER AND RECEIVE MMI COMMON STOCK; AND/OR  

(b) ROLL-OVER YOUR OPTION, IN WHOLE OR IN PART, FOR A NEW OPTION OVER MMI
    COMMON STOCK.

You should read the terms and conditions applying to the Recommended Proposals
overleaf.  By signing this Acceptance Form you agree to be bound by the terms
and conditions set out overleaf.  

NOTE: IF YOU ACCEPT THE OPTION ROLL-OVER PROPOSAL, YOU SHOULD BE AWARE THAT WHEN
YOU SUBSEQUENTLY WANT TO EXERCISE YOUR NEW OPTION YOU WILL BE ABLE TO USE A
CASH-LESS EXERCISE FACILITY WHICH MMI HAS ARRANGED WITH SMITH BARNEY INC.  MORE
INFORMATION IS AVAILABLE BY TELEPHONING MICHAEL J GALLAGHER OF SMITH BARNEY INC.
ON 001 312 419 3534.

SECTION B: YOUR SIGNATURE

Once you have made your choice and completed Section A you should sign Section
B.  PLEASE MAKE SURE YOU RETURN YOUR ACCEPTANCE FORM TO TREVOR SMITH TO ARRIVE
NO LATER THAN 3.00PM ON FRIDAY 28 NOVEMBER 1997.

You should keep these guidance notes and the terms and conditions overleaf for
your future reference.

<PAGE>

                                 TERMS AND CONDITIONS

1.     BY SIGNING THIS ACCEPTANCE FORM: 

1.1    I acknowledge receipt of the Prospectus and the letter from MMI and
       Unionamerica dated 5 November 1997;

1.2    I hereby warrant that my Option is valid and subsisting;

1.3    I hereby irrevocably authorise and direct Unionamerica or any person
       nominated by Unionamerica to execute any document and do any such thing
       on my behalf as may be necessary or desirable to give effect to any
       acceptance(s) made by me pursuant to Section A of this Acceptance Form;

2.     BY COMPLETING SECTIONS A AND B OF THIS ACCEPTANCE FORM, I AGREE AS
       FOLLOWS:

2.1    EXERCISE MY OPTION AND ACCEPT THE OFFER (IN WHOLE OR IN PART) - BOX 3
       AND BOX 5, SECTION A

       Conditional upon the Offer becoming or being declared unconditional in
       all respects and immediately prior to Closing, I hereby exercise my
       Option (in whole or in part) in respect of which I have ticked box 3 or
       box 5 of Section A.  I hereby irrevocably authorise Unionamerica or its
       agent to accept the Offer on my behalf in respect of the Unionamerica
       Securities I receive as a result of exercising my Option in respect of
       which I have ticked box 3 or box 5 of Section A.  I hereby authorise and
       request MMI or its agent to send me to my above address at my risk a
       certificate for the MMI Common Stock to which I am entitled.

2.2    ACCEPT THE OPTION ROLL-OVER PROPOSAL (IN WHOLE OR IN PART) - BOX 4 AND
       BOX 6, SECTION A

       Conditional upon the Offer becoming or being declared unconditional in
       all respects and immediately prior to Closing, I hereby accept the
       Option Roll-Over Proposal in respect of my Option in respect of which I
       have ticked box 4 or box 6 of Section A.  I hereby authorise and request
       MMI or its agent to send me at my risk a new option certificate for my
       New Option over MMI Common Stock to my above address.

3.     ACCEPTANCE FORMS WHICH ARE WRONGLY COMPLETED

       I agree that MMI reserves the right to accept any Acceptance Form which
       is wrongly completed or which is received after Friday 28 November 1997. 
       Subject to this:

       (a)    if I have completed the Acceptance Form, but not signed it, I
              accept that the Acceptance Form is of no effect;

       (b)    if I have signed the Acceptance Form, but failed to tick any of
              the boxes in Section A, I accept that I will be treated as having
              ticked box 4 of Section A (i.e that I have elected to accept the
              Option Roll-Over Proposal in full); and

       (c)    if I have signed the Acceptance Form and ticked more than one box
              against my Option (other than the boxes in box 5 or box 6), I
              accept that I will be treated as having ticked box 4 of Section A
              (i.e that I have elected to accept the Option Roll-Over Proposal
              in full).

4.     MISCELLANEOUS    

       Accidental omission to despatch this document or the Acceptance Form to,
       or any failure to receive the same by, any person to whom the
       Recommended Proposals are made or should be made, shall not invalidate
       the Recommended Proposals in any way.

       All acceptances of the Recommended Proposals shall be irrevocable.

       Receipt of documents will not be acknowledged.  All documents and
       remittances sent by, or to, you will be sent at your risk.   

<PAGE>

                                                                 Exhibit (a)(12)
                     PRESS RELEASE OF MMI DATED NOVEMBER 6, 1997
                                           

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN OR INTO
CANADA, AUSTRALIA OR JAPAN
MMI COMPANIES, INC. 
- --------------------------------------------------------------------------------
540 Lake Cook Road - Deerfield, Illinois 60015-5290 - 847-374-2400  FAX
847-940-2372
                                                           CONTACT:  Paul Orzech
                                                                    847-374-2369

      MMI COMPANIES, INC. COMMENCES EXCHANGE OFFER FOR UNIONAMERICA HOLDINGS PLC
                     MMI SPECIAL MEETING SET FOR DECEMBER 5, 1997
                                           
     DEERFIELD, IL, November 6, 1997 MMI Companies, Inc. (NYSE:MMI) announced
today that the Registration Statement for its exchange offer to holders of
Unionamerica Holdings plc (NYSE:UA) ordinary shares, including shares
represented by American Depositary Shares (ADSs), has been declared effective by
the Securities and Exchange Commission.  Accordingly, MMI is distributing today
exchange offer documents to Unionamerica securityholders and definitive proxy
materials to MMI stockholders.  The exchange offer is in connection with the
proposed acquisition of Unionamerica by MMI in a stock for stock transaction
announced on June 25, 1997.
     
     B.  Frederick Becker, Chairman and CEO of MMI commented, "The Unionamerica
acquisition represents an important strategic step for MMI's business and an
opportunity to improve our market position.  The track record of Unionamerica
combined with its experienced management team provides us with a stronger
foundation for international growth."  Mr. Becker added that MMI intends to
continue to operate Unionamerica as a distinct business entity under its present
management.
     
     Under the terms of MMI's exchange offer to acquire the whole of the issued
share capital of Unionamerica, which are set forth in the Offer to
Exchange/Prospectus dated November 5, 1997 (Prospectus), and the related Letter
of Transmittal, dated November 6, 1997, holders of Unionamerica ADSs will
receive 0.836 shares of MMI Common Stock for each ADS tendered.  MMI has
received undertakings to accept the offer from selling stockholders representing
50.2% of Unionamerica's outstanding ADSs as of October 31, 1997.  The Expiration
Date for the exchange offer, unless extended, is December 5, 1997.  The offer is
subject to a number of conditions (which may, in certain circumstances, be
waived by MMI) including the acceptance of the offer by holders of at least 90%
of Unionamerica's ordinary shares, approval of the issuance of shares of MMI
Common Stock by MMI's stockholders and certain regulatory approvals in the U.S.
and U.K.
     
     MMI has obtained regulatory consents from the U.K. Department of Trade and
Industry and Lloyds of London, as well as the Federal Trade Commission, which
has granted the request of


<PAGE>

MMI for early termination of the waiting period under the Hart-Scott-Rodino
Antitrust Improvements Act of 1976, as amended.
     
     The Board of Directors of Unionamerica has determined that the terms of the
offer are fair to, and in the best interests of, holders of Unionamerica ADSs
and has unanimously recommended that Unionamerica securityholders tender their
ADSs in the offer.
     
     The Board of Directors of MMI believes that the terms of the offer are fair
to, and in the best interests of, MMI and its stockholders, and recommends that
holders of MMI Common Stock vote for approval of the issuance of shares in
connection with the proposed acquisition.
     
     MMI also announced that it will hold a special meeting on December 5, 1997,
to approve the issuance of MMI Common Stock in connection with the acquisition
of Unionamerica.  MMI stockholders of record as of October 7, 1997 will be
entitled to attend and vote at the special meeting.
     
     Founded in 1971, Unionamerica's operating subsidiary, Unionamerica
Insurance Company Limited, is a specialty casualty and property reinsurer and
insurer operating in the London-based reinsurance and insurance markets. 
Unionamerica's core business is professional indemnity reinsurance (including
malpractice reinsurance for groups of healthcare providers, lawyers, and other
professionals), as well as casualty reinsurance and insurance for a variety of
U.S. single industry and/or single state risks.  Unionamerica has been granted
accredited or trusteed reinsurer status in 46 U.S. states and jurisdictions,
including New York, Texas, Illinois, and California, and, additionally, is an
approved or eligible excess and surplus lines insurer in 50 U.S. states and
jurisdictions.
     
     MMI Companies, Inc. is an international healthcare risk management company
with more than 20 years experience providing a wide range of products and
services that help the healthcare industry manage risks associated with the
delivery of care.  Through its operating subsidiaries, MMI provides strategic
consulting services, clinical risk management and operational consulting
services, and insurance and reinsurance products to the healthcare industry.  In
addition to its Deerfield headquarters, MMI has a network of offices throughout
the United States and overseas.
     
     This news release does not constitute an offer to exchange Unionamerica
ADSs for MMI Common Stock.  Such an offer may only be made pursuant to the
Prospectus and related Letter of Transmittal filed with, and declared effective
by, the Securities and Exchange Commission.  This news release does not
constitute a solicitation of a proxy from MMI stockholders.  Such a solicitation
is made only pursuant to definitive proxy materials filed with the Securities
and Exchange Commission.
     
     The Dealer Manager for the offer is Smith Barney Inc. Holders of
Unionamerica ADSs and MMI stockholders may obtain more information from the
Information Agent, ChaseMellon Shareholder Services L.L.C. at 1-800-549-9249.


                                          2


<PAGE>

                                                                 Exhibit (a)(13)

                 PRESS RELEASE OF UNIONAMERICA DATED NOVEMBER 6, 1997
                                           

[LOGO]         Unionamerica Holdings plc
                                                            NEWS

FOR IMMEDIATE RELEASE
- ---------------------                   Contact:  James O'Brien
- ---------------------                             Broadgate Consultants, Inc.
                                                  (212) 232-2222


                   UNIONAMERICA HOLDINGS PLC ANNOUNCES ITS APPROVAL
                           OF THE EXCHANGE OFFER COMMENCED
                                BY MMI COMPANIES, INC.

                           -------------------------------
                                           
LONDON, ENGLAND, November 6, 1997 - Unionamerica Holdings plc (NYSE:  UA)
announced today that it has recommended that the holders of Unionamerica ADSs
tender their ADSs in the exchange offer commenced by MMI Companies, Inc. (NYSE: 
MMI).  MMI announced today that the Registration Statement for the exchange
offer has been declared effective by the Securities and Exchange Commission and
that it was distributing exchange offer documents to Unionamerica
securityholders.  The exchange offer is being made pursuant to the previously
announced Acquisition Agreement between Unionamerica and MMI dated June 25,
1997.

               Under the terms of MMI's exchange offer, which are set forth 
in the Offer to Exchange/Prospectus and the related Letter of Transmittal, 
holders of Unionamerica ADSs would receive 0.836 shares of MMI Common Stock 
for each ADS tendered in the offer.  MMI is making the offer for all of 
Unionamerica's outstanding ADSs.  MMI has received undertakings to accept the 
offer from selling stockholders representing 50.21% of Unionamerica's 
outstanding ADSs as of October 31, 1997.
               
               The Board of Directors of Unionamerica, as detailed in the 
Schedule 14D-9 filed today with the Securities and Exchange Commission, has 
determined that the exchange offer is fair to, and in the best interests of, 
holders of Unionamerica ADSs and has recommended that the holders of 
Unionamerica ADSs exchange their ADSs pursuant to the terms of the exchange 
offer.
   
               Founded in 1971, Unionamerica's operating subsidiary, 
Unionamerica Insurance Company Limited, is a specialty casualty and property 
reinsurer and insurer operating in the London-based reinsurance and insurance 
markets.  The company's core business is professional

<PAGE>

indemnity reinsurance (including malpractice reinsurance for groups of
healthcare providers, lawyers, and other professionals), as well as casualty
reinsurance and insurance for a variety of U.S. single industry and/or single
state risks.  The company has been granted accredited or trusteed reinsurer
status in 46 U.S. states and jurisdictions, including New York, Texas, Illinois,
and California, and additionally, is an approved or eligible excess and surplus
lines insurer in 50 U.S. states and jurisdictions.
               
               MMI is an international healthcare risk management company 
with more than 20 years experience providing a wide range of products and 
services that help the healthcare industry enhance its performance and manage 
risks associated with the delivery of care.  Through its operating 
subsidiaries, MMI provides strategic consulting services, clinical risk 
management and operational consulting services, and insurance and reinsurance 
products to the healthcare industry.  In addition to its Deerfield 
headquarters, MMI has a network of offices throughout the United States and 
overseas.
               
The news release does not constitute an offer to exchange Unionamerica ADSs for
MMI Common Stock.  Such an offer may only be made pursuant to the Offer to
Exchange/Prospectus and related Letter of Transmittal filed by MMI with, and
declared effective by, the Securities and Exchange Commission.


                                          2


<PAGE>

                                                                  Exhibit (c)(1)

                                 FORM OF UNDERTAKING
                                           
                        IRREVOCABLE UNDERTAKING OF SHAREHOLDER
                                           

To:   MMI Companies, Inc. (the "Offeror")
      540 Lake Cook Road
      Deerfield
      Illinois 60015
      USA                                                           25 June 1997


Dear Sirs

Proposed offer for Unionamerica Holdings plc (the "Offeree" or the "Company")

1.   This letter sets out the terms on which the undersigned (the "Seller")
     undertakes to accept the tender offer to be made by the Offeror or on its
     behalf (the "Offer") to acquire the whole of the issued ordinary share
     capital of the Offeree.

2.   The Offer shall be made on the terms of that certain Acquisition
     Agreement, dated the date hereof, between the Offeror and the Offeree
     (the "Acquisition Agreement") and:

     (a) any additional terms and conditions as may be required to comply
         with the requirements of the Securities and Exchange Commission,
         the Securities Act of 1933, as amended, the New York Stock
         Exchange Inc. and the City Code on Takeovers and Mergers (the
         "Code") (collectively, "applicable law or regulation") but only to
         the extent such additional terms and conditions do not have a
         material adverse effect on the Seller or any of its interests;
         and/or

     (b) any other additional terms and conditions agreed in writing
         between the Offeror and the Offeree.

3.   The Seller warrants and undertakes to the Offeror that:

     (a) the Seller is the holder of the number of American Depositary
         Shares ("ADSs") representing ordinary shares of US$0.0448 each in
         the capital of Offeree ("Offeree Ordinary Shares") specified in
         the first column of the schedule attached hereto;


<PAGE>

     (b) those Offeree Ordinary Shares are free from any lien, charge or
         other encumbrance, equity or third party right of any nature that
         would prohibit the irrevocable acceptance of the Offer; and

     (c) the Seller has full power and authority to accept the Offer in
         respect of those Offeree Ordinary Shares.

4.

4.1  Subject to paragraph 18.3, the Seller shall irrevocably accept or procure
     the irrevocable acceptance of the Offer (or any improved or increased
     offer which may be made by or on behalf of the Offeror) in respect of:

     (a) the Offeree Ordinary Shares specified in the first column of the
         schedule;

     (b) any other Offeree Ordinary Shares which the Seller acquires after
         signing this undertaking; and

     (c) any other Offeree Ordinary Shares attributable to or deriving from
         the shares referred to in paragraphs 4.1(a) and 4.1(b).

     together, the "Shares".

4.2  The Seller's irrevocable acceptance in respect of the Shares shall be
     made by 5.00 p.m. New York time on the fifth business day (as defined in
     Rule 14d-1 of Regulation 14D promulgated under the Securities Exchange
     Act of 1934) after the formal document containing the Offer (the "Offer
     Document") is despatched to shareholders of the Offeree (or in relation
     to Offeree Ordinary Shares falling within either paragraph 4.1(b) or
     4.1(c), as soon as practicable after the Seller becomes the holder of
     such Offeree Ordinary Shares) in accordance with the procedure for
     acceptance set out in that document.

4.3  The Seller undertakes that the Shares which the Offeror will acquire
     pursuant to the Offer will be acquired free from any lien, charge, or
     other encumbrance, equity or other third party right of any nature and
     together with all rights of any nature attaching or accruing to them
     including the right to all dividends declared, made or paid after the
     date of this letter (other than as provided in the Acquisition
     Agreement).


                                          2
<PAGE>

4.4  The Seller is the holder of options to subscribe for the number of
     Offeree Ordinary Shares as specified in the fourth column of the
     scheduled attached hereto.  If the Seller exercises his subscription
     rights before the Offer lapses or is withdrawn, the Seller shall accept
     the Offer in respect of the Offeree Ordinary Shares subscribed for.  If
     the Seller does not exercise his options before the Offer lapses or is
     withdrawn, Offeror shall make a proposal in respect of options which
     provides benefits comparable on an economic basis (including as to timing
     of vesting) to those available under the current Company stock option
     plans and complies with the requirements of Section 368(a)(1)(B) of the
     Internal Revenue Code of 1986, as amended and all other applicable law
     and/or regulations and the Seller shall either accept such proposals in
     respect of his options or allow his options to lapse.

5.   In order to secure the performance of the Seller's obligations under
     paragraph 4, the Seller irrevocably appoints any director for the time
     being of the Offeror to be the Seller's attorney in the Seller's name and
     on the Seller's behalf to execute a Letter of Transmittal or forms of
     acceptance and/or such other documents and to do such other acts and
     things as may be necessary to accept (or procure the acceptance of) the
     Offer in respect of the Shares.  However, this conditional appointment
     shall not take effect until the tenth business day after the date of
     despatch of the Offer Document and only then if the Seller has failed to
     comply with its obligations in paragraph 4.  The Offeror shall give
     prompt written notice to the Seller of any activities by the Offeror on
     behalf of the Seller pursuant to the provisions of this paragraph 5.

6.   Even if the terms of the Offer give accepting shareholders the right to
     withdraw acceptances, the Seller shall not withdraw or procure the
     withdrawal of acceptances in respect of the Shares save as provided in
     this undertaking.

7.   Even if the terms of the Offer give the Offeror the right to waive in
     whole or in part any of the conditions to the closing of the Offer set
     out in Article IX of the Acquisition Agreement or the equivalent
     conditions in the Offer Document, the Offeror undertakes to the Seller
     not to waive any of conditions set out in section 9.01 or section 9.03 of
     the Acquisition Agreement or the equivalent conditions in the Offer
     Document in whole or in part without the consent of the Offeree, as
     evidenced by a copy of a resolution of the board of directors of the
     Offeree certified by a director or by the company secretary of the
     Offeree.

8.   Until the Offer becomes or is declared unconditional in all respects,
     lapses or is withdrawn:


                                          3
<PAGE>

     (a) the Seller shall exercise or procure the exercise of the voting
         rights attached to the Shares to vote in favour of the special
         resolution to be proposed at the extraordinary general meeting of
         the Company pursuant to section 6.04 of the Acquisition Agreement
         to amend the Articles of Association of the Company;

     (b) the Seller shall exercise or procure the exercise of the voting
         rights attached to the Shares as instructed by the Offeror on any
         other resolution which would assist implementation of the Offer if
         it were passed or rejected at a general meeting of the Offeree
         unless the passage of such resolution would be materially adverse
         to the Seller;

     (c) the Seller shall not without the prior written consent of the
         Offeror signed by a duly authorised officer requisition in its
         capacity as a shareholder or join in the requisition in its
         capacity as a shareholder of any general meeting of the Offeree
         for the purpose of considering any resolution other than a
         resolution contemplated by paragraphs 8(a) or 8(b); and

     (d) the Seller shall not take any action or make any statement which,
         to the Seller's knowledge, is or is likely to be prejudicial to
         the success of the Offer (subject, in the case of a Seller who is
         a director of the Offeree, to the fiduciary duties of such Seller
         as a director of the Offeree and such Seller's duties as a
         director under applicable law or regulation).

9.   The Seller agrees to details of this undertaking being set out in the
     Offer Document and this undertaking being available for inspection (if
     required by the Panel on Takeovers and Mergers) during the offer period
     (as defined in the Code).

10.  The Seller shall supply the Offeror promptly on request with all
     information, including details of the Seller's interests and dealings in
     securities of the Offeror and the Offeree, and those of any other person
     interested in the Shares, as may be required by applicable law or
     regulation for inclusion in the Offer Document.  The Seller shall notify
     the Offeror promptly of any changes to such information.

11.  The Offeror's agreement to make the Offer is conditional on:


                                          4
<PAGE>

     (a) the receipt by the Offeror not later than noon New York time on
         11 July 1997 of irrevocable undertakings substantially in the form
         of this undertaking in respect of not less than 50.1 per cent of
         the Offeree Ordinary Shares in issue or such lesser amount as the
         Offeror shall agree; and

     (b) no event occurring or becoming known to the Offeror before
         despatch of the Offer Document as a result of which the Offeror is
         required under applicable law or regulation not to make the Offer.

12.  This undertaking, including the appointment contained in clause 5, will
     lapse and terminate, and the Seller shall be entitled to withdraw any
     acceptance(s) of the Offer, if:

     (a) the Acquisition Agreement terminates or is terminated pursuant to
         its terms, or is amended by an amendment that is materially
         adverse to the Seller (and for this purpose any reduction in the
         Exchange Ratio (as defined in the Acquisition Agreement) shall be
         deemed to be materially adverse to the Seller); or

     (b) the Offer lapses or is withdrawn.

     If the undertaking lapses and terminates, the Seller shall have no claim
     against the Offeror and the Offeror shall have no claim against the
     Seller in respect of the provisions of this undertaking save in
     circumstances where paragraph 7 or paragraph 18 applies in which event
     the Seller and the Offeror shall remain liable to each other in respect
     of their respective obligations contained in paragraph 7 or paragraph 18.

13.  Any date, time or period referred to in this undertaking shall be of the
     essence except to the extent to which the Seller and the Offeror agree in
     writing to vary any date, time or period, in which event the varied date,
     time or period shall be of the essence.

14.  The Seller has been given a realistic opportunity to consider whether or
     not the Seller should give this undertaking and the Seller has received
     independent advice about the nature of this undertaking.

15.  The Seller and the Offeror agree that damages would not be an adequate
     remedy for breach of their respective obligations under this undertaking.


                                          5
<PAGE>

16.  The Seller acknowledges that, in connection with the Offer, Smith Barney
     Inc. is acting for the Offeror and for no-one else and agrees that Smith
     Barney Inc. will not be responsible to the Seller for providing the
     protections afforded to its customers nor for providing advice in
     relation to the Offer.

17.  A notice or other communication to be given under or in connection with
     this undertaking must be in writing and must be delivered personally or
     sent by express courier service (receipt acknowledged) or by fax to the
     party due to receive the notice or communication, at its authorised
     address.  In the absence of evidence of earlier receipt, a notice or
     other communication is deemed given if:

     (a) delivered personally or by express courier service, at the time of
         delivery; or

     (b) sent by fax, upon receipt by the sender of a fax report (or other
         appropriate evidence) that the fax has been transmitted to the
         addressee,

     provided that where delivery occurs or transmission is received after
     6.00 p.m. on a business day or on a day which is not a business day,
     receipt shall be deemed to occur at 9.00 a.m. on the next following
     business day.

     For the purpose of this clause the authorised address of each party shall
     be the address set out below (including the details of the fax number and
     person for whose attention a notice or communication is to be addressed)]
     or such other address (and details) as that party may notify to the other
     in writing from time to time in accordance with the requirements of this
     clause:

     The Offeror:            MMI Companies, Inc.
     Address:                540 Lake Cook Road, Deerfield, Illinois 60015 USA
     Facsimile No:           + 1 847 374 1330
     Attention:              Paul M. Orzech


                                          6
<PAGE>

     The Seller:
     Address:
     
     Facsimile No:
     Attention:
     
18.  Break up fees in the event of a higher competing offer

18.1 Scope:

     For the purposes of this paragraph:

     (a) the expression Higher Competing Offer means, only as determined in
         accordance with paragraph 18.2 below, a general offer for all or
         part of the Offeree Ordinary Shares under which the value of the
         consideration per Offeree Ordinary Share available at the time it
         is made (the "Valuation Time") exceeds the value of the
         consideration per Offeree Ordinary Share available under the Offer
         at the time (or which would have been available under the Offer at
         the time if the Offer were still available) on the assumption, in
         each case, that any rights to elect to receive different forms of
         consideration (including rights to accept underwritten cash
         alternatives or other collateral offer) are exercised in such
         manner as maximises that value but ignoring the possible impact of
         any "mix and match" or similar arrangement under which
         shareholders and/or stockholders in the Offeree can elect, subject
         to the elections of other shareholders, to vary the proportion in
         which they receive different forms of consideration; and

     (b) the announcing or making of any revised offer shall be deemed to
         constitute the announcing or making or a new offer.

18.2 Conclusive determination

     If, prior to the lapsing or termination of this undertaking as provided
     in paragraph 12 or within 90 calendar days thereafter if such lapsing or
     termination results from the termination of the Acquisition Agreement
     (i) by the Offeror under section 10.01(d) thereof as a result of a breach
     by the Company of a representation and warranty specified in Article IV
     of the a breach by the Company of a representation and warranty specified
     in Article IV of the 


                                          7
<PAGE>

     Acquisition Agreement or a covenant of the Company specified in
     Article VI or VIII of the Acquisition Agreement which breach resulted
     from the wilful misconduct, gross negligence or knowing and voluntary
     affirmative action of the Company or (ii) by the Company, other than
     under section 10.01 thereof, a third party announces a firm intention to
     make (for the purposes of Rule 2.5 of the Code or Rule 135 under the
     Securities Act of 1933) or makes a general offer for all or part of the
     Offeree Ordinary Shares the Seller shall be entitled within ten business
     days thereafter to serve on the Offeror, and the Offeror shall be
     entitled within ten business days thereafter to serve on the Seller, a
     notice stating that in the Seller's or, as the case may be, the Offeror's
     opinion the relevant offer either is or is not a Higher Competing Offer
     (an "Opinion Notice").  If within seven days of the date of service of
     any Opinion Notice, the recipient has not by notice in writing to the
     giver of the Opinion Notice indicated that the recipient disagrees with
     the relevant opinion (a "Dissent Notice") then that option shall be final
     and binding on both parties.  Paragraphs 18.3 and 18.4 below shall apply
     or not apply accordingly.  If, however, a Dissent Notice is served within
     that period then, at any time thereafter, either party shall be entitled
     to refer the question whether or not the relevant offer is a Higher
     Competing Offer to Donaldson, Lufkin & Jenrette Securities Corporation
     ("DLJ"), as financial adviser to the Offeree, or such other
     internationally recognised US investment bank as the parties shall agree
     (the "Expert").  The parties shall then use their reasonably endeavours
     to ensure that the Expert expresses its opinion on that question as soon
     as is reasonably practicable and that option shall in the absence of
     fraud or manifest error be final and binding on the parties and
     paragraphs 18.3 and 18.4 below shall apply or not apply accordingly.  The
     Expert shall act as an expert and not as an arbitrator and shall not be
     obliged to given reasons for its decision, except that if DLJ shall act
     as the Expert, DLJ shall communicate the reasons for its decision to
     Smith Barney Inc. as financial adviser to the Offeror.  The Expert's
     charges shall be divided between the parties as it shall determine.

18.3 Obligation to accept

     If a Higher Competing Offer is made or a firm intention to make a Higher
     Competing Offer is publicly announced prior to the latest time for
     acceptance of the Offer in respect of any Shares, then the Seller's
     obligations under paragraph 4 shall be suspended.  If prior to midnight
     on the tenth business day after the day on which the relevant Higher
     Competing Offer is made or, if earlier, publicly announced (the "Revision
     Deadline"), the Offeror announces a revision of the Offer which provides
     (in the reasonable opinion of DLJ 


                                          8
<PAGE>

     substantially equivalent or greater consideration than the Higher
     Competing Offer (a "Higher Revised Offer"), then the suspension shall
     come to an end and paragraph 4 shall thereafter be construed as if it
     provided that the forms of acceptance in respect of the relevant Shares
     (if not already delivered to the Buyer pursuant to paragraph 4) be
     returned not later than 5.00 p.m. New York time on the fifth business day
     after the announcement of the revision.

18.4 Other Obligations

     If a Higher Competing Offer is made or a firm intention to make a Higher
     Competing Offer is publicly announced and the Offeror has not announced a
     Higher Revised Offer before the Revision Deadline then all obligations
     under this undertaking shall immediately lapse and, in particular
     (without limitation), the Seller (subject as provided below) shall be
     entitled to withdraw any acceptance(s) of the Offer in accordance with
     the terms thereof, PROVIDED THAT the Seller shall not be entitled to
     withdraw any such acceptance(s) of the Offer and undertakes not to tender
     the Shares by way of acceptance of the Higher Competing Offer or
     (subject, in the case of a Seller who is a director of the Offeree, to
     his fiduciary duties as a director of the Offeree and his duties under
     applicable law or regulation) take any other action to frustrate the
     Offer or assist the implementation of the Higher Competing Offer unless
     and until the Seller (or any other person who has given the Offeror an
     undertaking substantially in the form of this undertaking) has made or
     procured the lawful payment (whether by the third party making the Higher
     Competing Offer or otherwise) to the Offeror of US$5,000,000 in aggregate
     amount, such payment being made for same day value, and in full discharge
     of all rights which the Offeror may have against the Company under the
     Acquisition Agreement.  Notwithstanding any restriction otherwise
     contained herein or in the Acquisition Agreement, (a) in the event a
     Higher Competing Offer is made or a firm intention to make a Higher
     Competing Offer is communicated to the Seller or to the Company or is
     publicly announced, the Seller may negotiate and agree with any person
     making or announcing the Higher Competing Offer the terms and conditions
     thereof, including the obligation to make the payment described herein
     and the means of making such payment and (b) if the Offeror has not made
     a Higher Revised Offer in accordance with paragraph 18.3 and has received
     the payment specified in this paragraph 18.4, the Offeror acknowledges
     that the Offeree shall be entitled to terminate the Acquisition Agreement
     and that this undertaking shall lapse and terminate in all respects, each
     without further liability or obligation.


                                          9
<PAGE>

19.  Save as provided below, this undertaking is governed by English law and
     the Courts of England have exclusive jurisdiction to hear and decide any
     suit, action or proceedings and to settle any disputes which may arise
     out of or in connection with this letter and for these purposes each
     party irrevocably submits to the jurisdiction of the Courts of England. 
     Notwithstanding the foregoing, the proviso to paragraph 18.4 shall be
     governed by and construed, and the expression 'gross negligence' in
     paragraph 18.2 shall be construed, in accordance with the laws of the
     State of Delaware applicable to a contract executed and performed in that
     State without giving effect to the conflicts of laws principles thereof.


                                          10
<PAGE>

                        SCHEDULE

     Name of Seller:

- ---------------------------------------------------------------
       1                2             3                4
- ---------------------------------------------------------------
NUMBER OF ADSs     REGISTERED     BENEFICIAL     NO. OF SHARES 
                     HOLDER*        OWNER*         OVER WHICH
                                                  OPTIONS HELD
                                                   (IF ANY)**
- ---------------------------------------------------------------


- ---------------------------------------------------------------


- ---------------------------------------------------------------


- ---------------------------------------------------------------


*   Please identify how the Ordinary Shares set out in column 1 are held by
    appropriate entries in columns 2 and/or 3 if not all beneficially owned by
    Seller

**  Applicable to options held under the 1993 and 1996 Stock Option Plans only. 
    If none, write 'None'.


                                          11
<PAGE>

Executed as a Deed           )
by                           )
acting by:                   )

                             Signature of authorised signatory or agent
- -------------------------
                             Name of authorised signatory or agent
- -------------------------
                             Signature of second authorised signatory or agent
- -------------------------    (if required)

                             Name of second authorised signatory or agent
- -------------------------    

OR

Executed as a Deed           )
by                           )
in the presence of:          )

Witness signature                                     
                             --------------------------------------------------
Name:                                       
                             --------------------------------------------------
Address:                                    
                             --------------------------------------------------
                                       
                             --------------------------------------------------
                                       
                             --------------------------------------------------

                             --------------------------------------------------
Occupation:                                      
                             --------------------------------------------------

Executed as a Deed           )
by MMI Companies, Inc.       )
acting by:                   )

                             Signature of authorised signatory or agent
- -------------------------    
                             Name of authorised signatory or agent
- -------------------------    
                             Signature of second authorised signatory or agent
- -------------------------    (if required)

                             Name of second authorised signatory or agent
- -------------------------    


                                          12


<PAGE>

                                                                  Exhibit (c)(2)


                             FORM OF AFFILIATES AGREEMENT


                                                                   June 25, 1997
MMI Companies, Inc.
540 Lake Cook Road
Deerfield, IL 60015-5290

Dear Sirs:

    The undersigned understands that you have entered into an Acquisition
Agreement dated as of June 25, 1997 (the "Acquisition Agreement"), by and
between you, MMI Companies, Inc., a Delaware corporation ("Buyer") and
Unionamerica Holdings plc, a corporation organized under the laws of England and
Wales (the "Company"), pursuant to which the Company shall become your wholly
owned subsidiary pursuant to the acquisition by you, solely for your voting
common stock, par value $0.10 per share (the "Buyer Common Stock"), of all of
the American Depository Shares ("ADSs"), representing all of the ordinary
shares, nominal value $0.0448 per share, of the Company (such ADSs being
referred to as "Company Common Stock"), and all of the deferred stock of the
Company, par value L1 per share (the "Company Deferred Stock"), through (i) the
Offer (as defined in the Acquisition Agreement) and (ii) the subsequent
compulsory acquisition of any remaining shares of Company Common Stock solely
for voting Buyer Common Stock (collectively, the "Transaction").

    The undersigned currently owns ___________ shares of Company Common Stock
and __________ options to purchase Company Common Stock which are currently
exercisable or are expected to become exercisable on or prior to Closing (such
Company Common Stock received upon the exercise of options or Buyer Common Stock
received therefor pursuant to the Transaction being referred to herein as
"Option Common Stock"). All Company Common Stock, Buyer Common Stock or Option
Common Stock now owned or hereafter acquired by the undersigned, is referred to
herein as the "Restricted Stock".

    The undersigned further understands that Buyer intends to account for the
acquisition of the Company as a pooling of interest and has been advised that
Accounting Series Release No. 135, as amended by Staff Accounting Bulletins Nos.
65 and 76 of the Securities and Exchange Commission, require that in a pooling
of interests, no affiliate, director or officer of either combining company may
reduce its risk relative to its common shareholder position within the period
beginning 30 days prior to consummation of a business combination and ending
when financial results covering at least 30 days of post-closing combined
operation have been published.



<PAGE>


June 25, 1997
Page 2


    In consideration of the execution of the Acquisition Agreement by Buyer,
and for other good and valuable consideration, the undersigned hereby
irrevocably agrees that during the period commencing 30 days prior to Closing
and ending when financial results of Buyer covering at least 30 days of post
Closing combined operations of Buyer and Company have been published, the
undersigned, without the prior written consent of Buyer, will not and, will not
announce or publicly disclose any intention to, sell, offer to sell, solicit an
offer to buy, contract to sell, grant any option to purchase, or otherwise
transfer or dispose of, any shares of Restricted Stock, or any securities
convertible into or exercisable or exchangeable for Restricted Stock.  The
foregoing restrictions shall not apply to any sale, transfer or other
disposition by the undersigned (i) to a member of the undersigned's immediate
family, or (ii) to a trust for the benefit of the undersigned or a member of the
undersigned's immediate family; provided that in each such case the undersigned
delivers to Buyer, no later than three (3) days prior to any such sale or other
disposition (A) written notice describing the terms of such sale, transfer or
other disposition and (B) the written agreement of the transferee to be bound by
the terms of this letter agreement. The undersigned's "immediate family"
consists of his or her spouse, parents, children (including adoptive),
grandchildren, siblings, mothers- and fathers-in-law, sons- and daughters-in-law
and brothers- and sisters-in-law. If the undersigned is a limited partnership,
the following restrictions shall also not apply to any distribution made to its
limited partners according to the terms of the partnership agreement governing
such limited partnership  nor shall such stock be treated as Restricted Stock in
the hands of such limited partners for the purposes of this agreement following
any such distribution.

    Except as provided above, the undersigned agrees that the provisions of
this agreement shall be binding also upon his or her successors, assigns, and
personal representative.

    In furtherance of the foregoing, Buyer and Chase Mellon Shareholder
Services LLC, its transfer agent, are hereby authorized to decline to make any
transfer of securities if such transfer would constitute a violation or breach
of this letter agreement and you are authorized to place a restrictive legend
upon any shares of Restricted Stock to be received by men in the Transaction.

    It is understood that you will release the undersigned for his or her
obligation under this letter agreement in the event the Acquisition Agreement
(other that the provisions thereof which survive termination) shall be
terminated prior to the Closing.

    This agreement shall be governed by and construed in accordance with the
laws of the State of Delaware applicable to a contract executed and performed in
such state, without giving effect to the conflicts of the law principles
thereof.



<PAGE>

June 25, 1997
Page 3


    Capitalized terms used herein and not otherwise defined herein shall have
the meaning ascribed to them in the Acquisition Agreement

                                  Very truly yours,



                                  -------------------------------




<PAGE>
                                                          


            [LETTERHEAD OF PAUL, WEISS, RIFKIND, WHARTON & GARRISON]



                                             October 21, 1997


Unionamerica Holdings plc
London Underwriting Centre
3 Minster Court, Mincing Lane
London EC3R 7DD


                      MMI Companies, Inc. and Unionamerica Holdings plc
                             Registration Statement on Form S-4

Dear Sirs:

     We have acted as special United States tax counsel to Unionamerica 
Holdings plc (the "Company") in connection with the Registration Statement of 
Form S-4 (the "Registration Statement") of MMI Companies, Inc. ("MMI") filed 
with the Securities and Exchange Commission on July 25, 1997, as amended on 
September 23, 1997 and October 21, 1997. Capitalized terms used but not 
defined herein have the meanings specified in the Registration Statement.

     Subject to the assumptions and limitations set forth therein and in this 
letter, we hereby confirm to you our opinion as set forth in the Registration 
Statement in the discussion under the heading "The Offer -- Tax Consequences of 
the Offer -- U.S. Taxation."


<PAGE>
                                                                            2


     In connection with this opinion, we have assumed the following:

     (1) The Proposed Acquisition will be effected in accordance with the 
Acquisition Agreement.

     (2) The facts, representations and covenants contained in letters to us 
from the Company dated October ____, 1997, MMI dated October ___, 1997, UA 
Partners, L.P. dated October 15, 1997, Keystone, Inc. dated October 15, 1997, 
UA Partners II, L.P. dated October ___, 1997, and Centre Reinsurance Limited 
dated October 10, 1997, were true and correct when made and will remain true 
and correct through the consummation of the Proposed Acquisition.

     (3) The Minimum Acceptance Condition has not been waived.

     (4) All acquisitions by MMI of Company stock, including the acquisition 
of remaining Unionamerica ADSs after the Expiration Date in a Compulsory 
Acquisition or otherwise, will be made solely in exchange for MMI voting 
stock.

     (5) The IRC Voting Provisions and the Section 212 Provisions will not 
apply to any shares of Company stock on the Expiration Date.

     We hereby consent to the filing of this opinion with the Securities and 
Exchange Commission as an exhibit to the Registration Statement and the 
references to us under the headings "Prospectus Summary -- Tax Consequences of 
the Offer" and "The Offer -- Tax Consequences of the Offer -- U.S. Taxation." 
In giving such consent, we do not thereby admit that we are in the category 
of persons whose consent is required under Securities Act of 1933 or the 
Securities Exchange Act of 1934 or the rules and regulations promulgated 
thereunder.


                                Very truly yours,



                                /s/ Paul, Weiss, Rifkind, Wharton & Garrison
                                ----------------------------------------------
                                 PAUL, WEISS, RIFKIND, WHARTON & GARRISON

<PAGE>
                                               

                         [LETTERHEAD OF LOVELL WHITE DURRANT]



                                                            October 21, 1997

Unionamerica Holdings plc
London Underwriting Centre
3 Minster Court
Mincing Lane
London
EC3R 7DD


Dear Sirs

MMI COMPANIES, INC. AND UNIONAMERICA HOLDINGS PLC
REGISTRATION STATEMENT ON FORM S-4

1.   We have acted as independent English legal advisors to Unionamerica 
     Holdings plc (the "Company") and have been requested by the Company to 
     give this opinion in connection with the Registration Statement on 
     Form S-4 filed with the United States Securities and Exchange Commission
     by MMI Companies, Inc. ("MMI") on July 25, 1997, as amended on 
     September 23, 1997 and October 21, 1997, for the purpose of registering 
     under the United States Securities Act of 1933 certain shares of MMI's 
     common stock to be issued in exchange for ordinary shares of US$0.0448 each
     represented by American Depositary Receipts ("ADRs") evidencing American 
     Depositary Shares ("ADSs") of the Company (the "Shares").

2.   In connection with this opinion, we have examined a copy of the 
     Registration Statement on Form S-4 (file number 333-32027) as filed with 
     the United States Securities and Exchange Commission under the United 
     States Securities Act of 1933 on ______________ 1997 (the "Registration 
     Statement"), including the prospectus contained therein (the 
     "Prospectus").

3.   This opinion is given only with respect to English law in force at the 
     date of this opinion, as applied by the English Courts. No opinion is 
     expressed or implied as to the laws of any other jurisdiction, as to 
     which no enquiries have been made. This opinion is given on the basis 
     that it is to be governed by and construed in accordance with English 
     law. Statements relating to United Kingdom taxation are based on the 
     laws of England as currently applied by the English Courts and on the 
     generally published practice of the Inland Revenue and H.M. Customs & 
     Excise applying as at the date of this opinion.



<PAGE>

Unionamerica Holdings plc                                     October 21, 1997
                                    -2-


4.   On the basis of and subject to the foregoing and the matters set out in 
     paragraph 5 below and subject to any matters not disclosed to us, and 
     having regard to such considerations of English law in force and the 
     generally published practice of the U.K. Inland Revenue and H.M. 
     Customs & Excise applying as at the date of this opinion as we have 
     considered relevant, we are of the opinion that the statements in the 
     Prospectus under the heading "The Offer -- Tax Consequences of the Offer" 
     insofar as such statements constitute a summary of the legal matters, 
     documents, or proceedings under the laws of England referred to therein, 
     constitute an accurate general description of the principal U.K. tax 
     consequences under English law associated with the exchange of securities
     pursuant to the Offer (which expression shall have the meaning attributed 
     to it in the Prospectus).

5.   We hereby consent to the filing of this opinion as an exhibit to the 
     Registration Statement and to the references to us in the Prospectus 
     under the headings "The Offer -- Tax Consequences of the Offer" and 
     "Legal Matters", but in giving this consent we do not thereby admit that 
     we come within the category of persons whose consent is required by the 
     United States Securities Act of 1933 or the Securities Exchange Act of 
     1934 or the rules and regulations promulgated thereunder.


Yours faithfully


/s/ Lovell White Durrant


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission