ACTIVE ASSETS CALIFORNIA TAX FREE TRUST
485BPOS, 1996-08-22
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<PAGE>
   
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON AUGUST 22, 1996
    
 
                                                    REGISTRATION NOS.:  33-41685
                                                                        811-6530
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                ----------------
 
                                   FORM N-1A
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933                     /X/
                          PRE-EFFECTIVE AMENDMENT NO.
                                      ----                                   / /
   
                         POST-EFFECTIVE AMENDMENT NO. 6                      /X/
    
                                     AND/OR
              REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY
                                  ACT OF 1940                                /X/
   
                                AMENDMENT NO. 7                              /X/
    
 
                              -------------------
 
                                 ACTIVE ASSETS
                           CALIFORNIA TAX-FREE TRUST
               (EXACT NAME OF REGISTRANT AS SPECIFIED IN CHARTER)
 
                             TWO WORLD TRADE CENTER
                            NEW YORK, NEW YORK 10048
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICE)
 
       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (212) 392-1600
 
                              SHELDON CURTIS, ESQ.
                             TWO WORLD TRADE CENTER
                            NEW YORK, NEW YORK 10048
                    (NAME AND ADDRESS OF AGENT FOR SERVICE)
 
                            ------------------------
 
                                    COPY TO:
                            DAVID M. BUTOWSKY, ESQ.
                             GORDON ALTMAN BUTOWSKY
                             WEITZEN SHALOV & WEIN
                              114 WEST 47TH STREET
                            NEW YORK, NEW YORK 10036
                                ----------------
 
                 APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING:
 As soon as practicable after this Post-Effective Amendment becomes effective.
 
 IT IS PROPOSED THAT THIS FILING WILL BECOME EFFECTIVE (CHECK APPROPRIATE BOX)
        _X_ immediately upon filing pursuant to paragraph (b)
        ___ on (date) pursuant to paragraph (b)
        ___ 60 days after filing pursuant to paragraph (a)
        ___ on (date) pursuant to paragraph (a) of rule 485.
 
   
    THE  REGISTRANT HAS REGISTERED AN INDEFINITE  NUMBER OF ITS SHARES UNDER THE
SECURITIES ACT OF  1933 PURSUANT  TO SECTION  (A) (1)  OF RULE  24F-2 UNDER  THE
INVESTMENT  COMPANY ACT OF 1940. THE REGISTRANT HAS FILED THE RULE 24F-2 NOTICE,
FOR ITS  FISCAL YEAR  ENDED JUNE  30,  1996, WITH  THE SECURITIES  AND  EXCHANGE
COMMISSION ON AUGUST 6, 1996.
    
 
           AMENDING THE PROSPECTUS AND UPDATING FINANCIAL STATEMENTS
 
            -------------------------------------------------------
            -------------------------------------------------------
<PAGE>
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
 
                             CROSS-REFERENCE SHEET
 
                                   FORM N-1A
 
ITEM                                              CAPTION
PART A                                          PROSPECTUS
1.  .....................  Cover (page 1 of Active Assets Money Trust
                           Prospectus)
2........................  Highlights; Summary of Trust Expenses; Financial
                           Highlights
3........................  Dividends, Distributions and Taxes (Appendix)
4........................  Investment Objectives and Policies; Highlights; The
                           Trusts and Their Management (Appendix)
5........................  Investment Objectives and Policies; The Trusts and
                           Their Management (Appendix); Back Cover
6........................  Dividends, Distribution and Taxes (Appendix); General
                            Information (Appendix)
7........................  How Net Asset Value is Determined (Appendix);
                           Purchase and Redemption of Shares (Appendix)
8........................  Purchase and Redemption of Shares (Appendix)
9........................  Not Applicable
PART B                              STATEMENT OF ADDITIONAL INFORMATION
10.......................  Cover Page
11.......................  Table of Contents
12.......................  Not Applicable
13.......................  Investment Practices and Policies; Investment
                           Restrictions
14.......................  Investment Manager (Appendix); Trustees and Officers
                            (Appendix)
15.......................  Investment Manager (Appendix); Trustees and Officers
                            (Appendix)
16.......................  Investment Manager (Appendix); Custodian and Transfer
                            Agent (Appendix); Experts (Appendix)
17.......................  Portfolio Transactions and Brokerage (Appendix)
18.......................  General Information (Appendix)
19.......................  How Net Asset Value is Determined; Experts (Appendix)
20.......................  Dividends, Distributions and Taxes
21.......................  Investment Manager (Appendix)
22.......................  Dividends, Distributions and Taxes
23.......................  Experts (Appendix)
 
PART C
 
    Information  required  to be  included  in Part  C  is set  forth  under the
appropriate item, so numbered, in Part C of this Registration Statement.
<PAGE>
                           ACTIVE ASSETS MONEY TRUST
                          ACTIVE ASSETS TAX-FREE TRUST
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
                              --------------------
 
    THIS  DOCUMENT CONSISTS  OF THE PROSPECTUSES  OF ACTIVE  ASSETS MONEY TRUST,
ACTIVE ASSETS TAX-FREE TRUST, ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST AND ACTIVE
ASSETS GOVERNMENT SECURITIES TRUST (COLLECTIVELY, THE "TRUSTS") AND AN  APPENDIX
TO  SUCH PROSPECTUSES  WHICH CONSTITUTES  PART OF  THE PROSPECTUSES.  A TABLE OF
CONTENTS IS CONTAINED ON PAGE 1 OF EACH PROSPECTUS.
                            ------------------------
 
    Each Trust is a diversified  open-end management investment company  seeking
high  current income, preservation of capital  and liquidity from investments in
short-term securities.  Active  Assets  Money  Trust  invests  in  money  market
instruments  generally; Active  Assets Tax-Free  Trust invests  in high quality,
short-term tax-exempt securities and pays dividends exempt from federal personal
income taxation;  Active  Assets  California  Tax-Free  Trust  invests  in  high
quality,  short-term California tax-exempt securities  and pays dividends exempt
from  federal  and  California  personal  income  taxation;  and  Active  Assets
Government  Securities  Trust  invests  in money  market  instruments  issued or
guaranteed by the United States Government or its agencies or instrumentalities.
 
    The Active Assets -Registered  Trademark- Account financial service  program
("Active Assets") of Dean Witter Reynolds Inc. ("Dean Witter") provides a medium
for  the  investment of  free credit  cash  balances held  in the  Active Assets
account in shares  of the  Trusts. An  Active Assets  account is  a Dean  Witter
securities  account (the "Securities Account") which  is linked to the Trusts, a
Federal Deposit Insurance Corporation ("FDIC") insured bank account (the "Active
Assets Insured  Account")  maintained  at  a bank  which  has  entered  into  an
agreement   with   Dean  Witter   to  participate   in   Active  Assets   and  a
Visa-Registered Trademark- check/card account maintained by Bank One,  Columbus,
N.A., Columbus, Ohio ("Visa Account").
 
    The  annual fee for participation in  the Active Assets program is presently
$80 ($100 for  corporations). Dean Witter  may charge certain  group or  special
accounts  a different fee. Dean Witter reserves  the right to change the fee for
participation in the  Active Assets  program at any  time. As  described in  the
Appendix to the Prospectus under the section "Purchase of Shares", shares of the
Trusts  may be purchased  by investors maintaining  brokerage accounts with Dean
Witter who  are not  subscribers  to the  Active  Assets program.  In  addition,
certain other Securities Accounts which are not subscribers to the Active Assets
Program  may be  linked to  the Trusts  and the  Active Assets  Insured Account.
Shareholders of the Trusts not subscribing to the Active Assets program will not
be charged the program fee.
 
    Subject to  the conditions  set forth  herein, a  subscriber to  the  Active
Assets  program  will have  his or  her free  credit cash  balances held  in the
account automatically  invested  daily  in  shares  of  any  of  the  Trusts  or
transmitted  to the  bank for  deposit into  the Active  Assets Insured Account,
depending upon which investment is selected  by the investor, and earn a  return
thereon  pending further investment of such funds in other aspects of the Active
Assets program or utilization  through the Visa  Account. A program  participant
may make additional investments in or change his or her chosen investment at any
time  by following the procedures set forth  in the Appendix under "Purchase and
Redemption of Shares".
                            ------------------------
 
    THE INFORMATION IN THIS DOCUMENT SHOULD BE READ IN CONJUNCTION WITH THE DEAN
WITTER  CLIENT  AGREEMENT  WHICH  IS  BEING  FURNISHED  TO  ALL  ACTIVE   ASSETS
SUBSCRIBERS  (OR OTHER ACCOUNT AGREEMENT  FOR NON-ACTIVE ASSETS SUBSCRIBERS) AND
WILL BE FURNISHED TO NEW SUBSCRIBERS PRIOR TO THE TIME AN ACTIVE ASSETS ACCOUNT,
OR OTHER SECURITIES ACCOUNT, IS OPENED.  REFERENCE IS MADE TO SUCH MATERIAL  FOR
INFORMATION  WITH RESPECT TO THE ACTIVE ASSETS AND OTHER PROGRAMS, INCLUDING THE
FEES RELATED THERETO. FOR MORE COMPLETE DETAILS ABOUT THE ACTIVE ASSETS  INSURED
ACCOUNT,  INCLUDING  PROCEDURES FOR  TRANSFERRING FROM  ANY  OF THE  TRUSTS, THE
SUBSCRIBER SHOULD CONSULT HIS OR HER DEAN WITTER ACCOUNT EXECUTIVE.
 
   
      For information on participation in the Active Assets program and
  information relating to a specific account, call:
     - Anywhere in the United        - In New York City (212)
     States, Puerto Rico and the       392-5000
       Virgin Islands toll free at
       (800) 869-3326
 
ACTIVE ASSETS IS A REGISTERED TRADEMARK OF DEAN WITTER REYNOLDS INC.  AUGUST 22,
1996
    
<PAGE>
TRUSTEES AND OFFICERS
 
ACTIVE ASSETS MONEY TRUST
ACTIVE ASSETS TAX-FREE TRUST
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
 
TRUSTEES
 
   
Michael Bozic
    
Charles A. Fiumefreddo
Edwin J. Garn
John R. Haire
Dr. Manuel H. Johnson
   
Michael E. Nugent
    
Philip J. Purcell
John L. Schroeder
 
OFFICERS
 
Charles A. Fiumefreddo
Chairman and Chief Executive Officer
 
Sheldon Curtis
Vice President, Secretary and
General Counsel
 
Jonathan R. Page
Vice President
 
Katherine H. Stromberg
Vice President
 
Thomas F. Caloia
Treasurer
<PAGE>
                           ACTIVE ASSETS MONEY TRUST
 
       TWO WORLD TRADE CENTER, NEW YORK, NEW YORK 10048 - (212) 392-5000
 
    Active  Assets Money Trust (the "Money Trust"  or the "Trust") is a no-load,
diversified open-end management investment company the investment objectives  of
which  are high current income, preservation of capital and liquidity. The Trust
is authorized to reimburse Dean  Witter Distributors Inc. for specific  expenses
incurred  in promoting the distribution of the Trust's shares pursuant to a Plan
of Distribution pursuant to Rule 12b-1 under the Investment Company Act of 1940,
as amended (the "Act"). Reimbursement may in no event exceed an amount equal  to
payments  at the  annual rate of  0.15% of the  average daily net  assets of the
Trust.
 
    The Trust will invest in a diversified portfolio of short-term money  market
instruments   consisting  primarily  of  United  States  Government  securities,
obligations of U.S.  regulated banks  and savings and  loan associations  having
assets  of $1  billion or  more, certificates  of deposit  of savings  banks and
savings and loan associations  having total assets of  $1 billion or more,  high
grade commercial paper, high grade corporate obligations maturing in one year or
less and certificates of deposit of $100,000 or less of U.S. regulated banks and
savings  institutions, having  total assets of  less than $1  billion, which are
fully insured by the FDIC.
 
    AN INVESTMENT IN  THE TRUST IS  NEITHER INSURED NOR  GUARANTEED BY THE  U.S.
GOVERNMENT.  THERE IS  NO ASSURANCE THAT  THE TRUST  WILL BE ABLE  TO MAINTAIN A
STABLE NET ASSET VALUE OF $1.00 PER SHARE.
 
    SHARES OF THE  TRUST ARE NOT  DEPOSITS OR OBLIGATIONS  OF, OR GUARANTEED  OR
ENDORSED  BY, ANY BANK, AND THE SHARES  ARE NOT FEDERALLY INSURED BY THE FEDERAL
DEPOSIT INSURANCE CORPORATION, THE FEDERAL RESERVE BOARD, OR ANY OTHER AGENCY.
                               TABLE OF CONTENTS
 
   
<TABLE>
<S>                                                 <C>
Highlights/2                                        How Net Asset Value is Determined/A-4
Summary of Trust Expenses/3                         Confirmations/A-5
Financial Highlights/3                              The Trusts and Their Management/A-5
Investment Objectives and Policies/4                Plan of Distribution/A-6
Investment Restrictions/5                           Dividends, Distributions and Taxes/A-6
Financial Statements -- June 30, 1996/6             General Information/A-9
Report of Independent Accountants/11                Voting Rights/A-9
Purchase and Redemption of Shares/A-1               Custodian/A-10
    Purchase of Shares/A-1                          Shareholder Inquiries/A-10
    Purchase of Shares by Non-Participants in
      Active Assets Program/A-2
    Redemption of Shares/A-3
    Redemption of Shares by Non-Participants in
      Active Assets Program/A-4
</TABLE>
    
 
   
    THIS PROSPECTUS SETS FORTH CONCISELY THE INFORMATION YOU SHOULD KNOW  BEFORE
INVESTING  IN THE TRUST.  IT SHOULD BE  READ AND RETAINED  FOR FUTURE REFERENCE.
ADDITIONAL INFORMATION  ABOUT  THE  TRUST  IS  CONTAINED  IN  THE  STATEMENT  OF
ADDITIONAL  INFORMATION, DATED  AUGUST 22, 1996,  WHICH HAS BEEN  FILED WITH THE
SECURITIES AND EXCHANGE  COMMISSION, AND WHICH  IS AVAILABLE AT  NO CHARGE  UPON
REQUEST  OF THE  TRUST AT  THE ADDRESS  LISTED ABOVE  OR BY  CALLING DEAN WITTER
INTERCAPITAL  INC.  (THE  "INVESTMENT  MANAGER"  OR  "INTERCAPITAL")  AT   (212)
392-2550.  THE  STATEMENT OF  ADDITIONAL INFORMATION  IS INCORPORATED  HEREIN BY
REFERENCE.
    
 
    THE INFORMATION IN THIS  PROSPECTUS SHOULD BE READ  IN CONJUNCTION WITH  THE
INFORMATION APPEARING ELSEWHERE IN THIS DOCUMENT, INCLUDING THE APPENDIX HERETO,
WHICH IS PART OF THIS PROSPECTUS, AND IN THE DEAN WITTER CLIENT AGREEMENT.
 
THESE  SECURITIES HAVE  NOT BEEN APPROVED  OR DISAPPROVED BY  THE SECURITIES AND
     EXCHANGE COMMISSION OR  ANY STATE  SECURITIES COMMISSION  NOR HAS  THE
        SECURITIES  AND  EXCHANGE  COMMISSION  OR  ANY  STATE SECURITIES
             COMMISSION  PASSED  UPON  THE  ACCURACY  OR   ADEQUACY
                 OF  THIS  PROSPECTUS.  ANY  REPRESENTATION  TO
                     THE CONTRARY  IS A  CRIMINAL  OFFENSE.
                           --------------------------
 
   
                THE DATE OF THIS PROSPECTUS IS AUGUST 22, 1996.
    
 
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
HIGHLIGHTS
 
   
<TABLE>
<S>                    <C>
THE                    A   no-load,  open-end  diversified  management  investment   company  investing  in  money  market
TRUST                  instruments. The  Trust is  authorized to  reimburse  Dean Witter  Distributors Inc.  for  specific
                       expenses  incurred  in promoting  the distribution  of the  Trust's  shares pursuant  to a  Plan of
                       Distribution pursuant to Rule  12b-1 under the Act.  (See page A-6). The  Trust is organized as  an
                       unincorporated business trust under the laws of Massachusetts. (See page A-5).
- ------------------------------------------------------------------------------------------------------------------------
SHARES                 The  shares of the  Money Trust are  offered to participants  in the Active  Assets program of Dean
OFFERED                Witter and to non-participants who wish to invest  directly in shares of the Trust (See page  A-2).
                       The  primary components of the Active Assets program are the Securities Account, which is linked to
                       the Active Assets Insured Account,  the Money Trust, the Active  Assets Tax-Free Trust, the  Active
                       Assets  California Tax-Free Trust or the Active Assets  Government Securities Trust and to the Visa
                       Account. See the Dean Witter Client Agreement for further information.
- ------------------------------------------------------------------------------------------------------------------------
PURCHASE               Pursuant to the Dean Witter Client Agreement between Dean Witter and the customer, free credit cash
OF SHARES              balances will be automatically invested in shares of the Money Trust daily at their net asset value
                       without any sales charge. Dean Witter Distributors Inc. is the Distributor of shares of the  Trust.
                       Investments  in shares are made under the circumstances described under "Purchase and Redemption of
                       Shares" (see  page  A-1).  Non-participants in  the  Active  Assets program  should  refer  to  the
                       discussion appearing at page A-2.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             High  current income, preservation of capital and liquidity (see page 4). There can be no assurance
OBJECTIVES             that the Trust's objectives can be achieved.
- ------------------------------------------------------------------------------------------------------------------------
AUTHORIZED             Money market instruments as follows (see page 4):
INVESTMENTS            - United States Government securities;
                       -   Obligations   of   U.S.   regulated   banks   having   assets   of   $1   billion   or    more;
                       - High grade commercial paper;
                       - High grade corporate obligations maturing in one year or less;
                       -  Certificates of deposit of savings banks and savings institutions having assets of $1 billion or
                       more;
                       - Certificates of deposit of  $100,000 or less, of U.S.  regulated banks and savings  institutions,
                       having    total   assets   of    less   than   $1    billion,   fully   insured    by   the   FDIC;
                       - Repurchase Agreements (see page 4).
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             Dean Witter  InterCapital  Inc.,  the  Investment  Manager  of  the  Trust,  and  its  wholly-owned
MANAGER                subsidiary,  Dean Witter Services Company, Inc.,  serve in various investment management, advisory,
                       management and administrative capacities to ninety-eight investment companies and other  portfolios
                       with assets of approximately $84.6 billion at June 30, 1996 (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
MANAGEMENT             Monthly  fee at an annual rate of 1/2 of 1% of average daily net assets, scaled down on assets over
FEE                    $500 million (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
DISTRIBUTOR            Dean Witter Distributors Inc.  (the "Distributor") sells  shares of the  Trust through Dean  Witter
                       Reynolds  Inc.  Other  than  the  reimbursement  to the  Distributor  pursuant  to  the  Rule 12b-1
                       Distribution Plan, the Distributor receives no distribution fees (see page A-2).
- ------------------------------------------------------------------------------------------------------------------------
PLAN OF                The Trust is authorized to  reimburse specific expenses incurred  in promoting the distribution  of
DISTRIBUTION           the  Trust's shares pursuant to a Plan of  Distribution with the Distributor pursuant to Rule 12b-1
                       under the Investment Company Act of 1940. Reimbursement  may in no event exceed an amount equal  to
                       payments at the annual rate of 0.15 of 1% of average daily net assets of the Trust (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
DIVIDENDS              Automatically reinvested daily in additional shares at net asset value (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
REPORTS                Individual  monthly account statements from  Dean Witter on the  Dean Witter Transaction Statement;
                       annual and semi-annual Trust financial statements.
- ------------------------------------------------------------------------------------------------------------------------
REDEMPTION             For participants in the Active Assets  program, shares of the Money  Trust will be redeemed at  net
OF SHARES              asset  value automatically to satisfy debit balances  in the Securities Account created by activity
                       therein or to satisfy amounts  owing in the Visa Account  resulting from Visa card purchases,  cash
                       advances  or checks written against the Visa Account. Non-participants in the Active Assets program
                       should refer to the discussion appearing  at page A-4. It is  anticipated that the net asset  value
                       will  remain constant at  $1.00 per share. Dean  Witter has the right  to terminate a shareholder's
                       Active Assets service,  in which event  all Trust shares  held in a  shareholder's account will  be
                       involuntarily  redeemed. The Trust  also reserves the right  to reduce the number  of shares in all
                       accounts if the Trustees determine that this is necessary to maintain the constant $1.00 per  share
                       net asset value. See "Purchase and Redemption of Shares" (page A-1).
- ------------------------------------------------------------------------------------------------------------------------
RISKS                  The Trust's investments are limited to U.S. Government securities, high grade corporate obligations
                       and  obligations of banks and savings and loan associations having assets of $1 billion or more and
                       fully insured Certificates  of Deposit;  consequently, the portfolio  securities of  the Trust  are
                       subject  to minimal risk of loss of income and  principal. However, the investor is directed to the
                       discussion of "Repurchase Agreements" (page 4) concerning the risks associated with such  portfolio
                       securities and management techniques.
- ------------------------------------------------------------------------------------------------------------------------
    THE  SUMMARY INFORMATION ABOVE SHOULD BE READ IN CONJUNCTION WITH THE DETAILED INFORMATION APPEARING ELSEWHERE IN THIS
PROSPECTUS, INCLUDING THE APPENDIX HERETO, IN THE DEAN WITTER CLIENT AGREEMENT AND IN THE TRUST'S STATEMENT OF  ADDITIONAL
INFORMATION, INCLUDING THE APPENDIX THERETO.
</TABLE>
    
 
                                       2
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
SUMMARY OF TRUST EXPENSES
- --------------------------------------------------------------------------------
 
    The  following table illustrates all expenses and fees that a shareholder of
the Trust will incur. The expenses and fees  set forth in the table are for  the
fiscal year ended June 30, 1996.
 
<TABLE>
<S>                                            <C>
SHAREHOLDER TRANSACTION EXPENSES
Maximum Sales Charge Imposed on Purchases....  None
Maximum Sales Charge Imposed on Reinvested
 Dividends...................................  None
Deferred Sales Charge........................  None
Redemption Fees..............................  None
Exchange Fee.................................  None
ANNUAL TRUST OPERATING EXPENSES (AS A
 PERCENTAGE OF AVERAGE NET ASSETS)
Management Fees..............................   0.30%
12b-1 Fees...................................   0.10%
Other Expenses...............................   0.07%
                                               ------
Total Trust Operating Expenses...............   0.47%
                                               ------
                                               ------
</TABLE>
 
<TABLE>
<CAPTION>
EXAMPLE                                                                 1 YEAR   3 YEARS    5 YEARS    10 YEARS
                                                                        ------   --------   --------   ---------
<S>                                                                     <C>      <C>        <C>        <C>
You would pay the following expenses on a $1,000 investment,
 assuming (1) 5% annual return and (2) redemption at the end
 of each time period:                                                     $5        $15        $26        $59
</TABLE>
 
    Dean Witter charges an annual Active Assets program participation fee of $80
($100 for corporate participants). Shareholders of the Trust who are not program
participants will not be charged an Active Assets program fee.
 
    The  above  example should  not be  considered a  representation of  past or
future expenses or performance. Actual expenses  of the Trust may be greater  or
less than those shown.
 
    The  purpose of this  table is to  assist the investor  in understanding the
various costs and expenses that an investor  in the Trust will bear directly  or
indirectly.  For a  more complete description  of these costs  and expenses, see
pages A-5 and A-6 in the Appendix to this Prospectus.
 
FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------
 
   
    The following ratios and per share  data for a share of beneficial  interest
outstanding  throughout each period  have been audited  by Price Waterhouse LLP,
independent accountants. The financial highlights should be read in  conjunction
with  the financial statements  and notes thereto and  the unqualified report of
independent accountants which are contained in the Prospectus commencing on page
6.
    
 
   
<TABLE>
<CAPTION>
                                                                   FOR THE YEAR ENDED JUNE 30,
                                -------------------------------------------------------------------------------------------------
                                 1996      1995      1994      1993      1992      1991      1990      1989      1988      1987
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
<S>                             <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>
PER SHARE OPERATING
 PERFORMANCE:
Net asset value, beginning of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net investment income.........   0.052     0.051     0.029     0.029     0.045     0.068     0.081     0.083     0.066     0.058
Less dividends from net
 investment income............  (0.052)   (0.051)   (0.029)   (0.029)   (0.045)   (0.068)   (0.081)   (0.083)   (0.066)   (0.058)
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net asset value, end of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
TOTAL INVESTMENT RETURN+......    5.33%     5.23%     2.99%     2.95%     4.58%     7.05%     8.43%     8.57%     6.83%     5.90%
RATIOS TO AVERAGE NET ASSETS:
  Expenses....................    0.47%     0.49%     0.51%     0.51%     0.54%     0.52%     0.50%     0.52%     0.54%     0.54%
  Net investment income.......    5.21%     5.16%     2.95%     2.90%     4.45%     6.80%     8.10%     8.33%     6.63%     5.78%
SUPPLEMENTAL DATA:
Net assets, end of period, in
 millions.....................  $7,170    $5,709    $4,144    $3,604    $3,628    $3,688    $3,454    $3,021    $2,519    $2,299
</TABLE>
    
 
- ------------
+ CALCULATED BASED ON  THE NET ASSET VALUE  AS OF THE LAST  BUSINESS DAY OF  THE
PERIOD.
 
                                       3
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
INVESTMENT OBJECTIVES AND POLICIES
- --------------------------------------------------------------------------------
 
    THE INVESTMENT OBJECTIVES OF THE TRUST ARE HIGH CURRENT INCOME, PRESERVATION
OF  CAPITAL  AND  LIQUIDITY. THE  TRUST  SEEKS  TO ACHIEVE  THOSE  OBJECTIVES BY
INVESTING IN THE FOLLOWING MONEY MARKET INSTRUMENTS:
 
U.S. GOVERNMENT SECURITIES--
 
obligations issued or  guaranteed as  to principal  and interest  by the  United
States  or its agencies  (such as the  Export-Import Bank of  the United States,
Federal Housing Administration, and Government National Mortgage Association) or
its instrumentalities (such as the Federal Home Loan Bank, Federal  Intermediate
Credit  Banks and  Federal Land  Bank), including  Treasury bills,  notes, bonds
(including zero coupon bonds) and coupons;
 
BANK OBLIGATIONS--
 
obligations (including certificates  of deposit, bankers'  acceptances and  bank
notes)  of banks subject to  regulation by the U.S.  Government and having total
assets of $1,000,000,000 or more,  and instruments secured by such  obligations,
including  obligations of  foreign branches  of domestic  banks (because  of its
relationship  to  the  Active  Assets  program,  the  Trust  will  not  purchase
securities  of Bank One, Columbus, N.A. or its affiliates and will not deal with
such Bank  or  its  affiliates as  a  principal  in the  purchase  and  sale  of
securities);
 
OBLIGATIONS OF SAVINGS INSTITUTIONS--
 
certificates  of deposit  of savings  banks and  savings and  loan associations,
having total assets of $1,000,000,000 or more;
 
FULLY INSURED CERTIFICATES OF DEPOSIT--
 
certificates of deposit of banks  and savings institutions, having total  assets
of  less  than $1,000,000,000,  if  the principal  amount  of the  obligation is
insured by the FDIC, limited to $100,000 principal amount per certificate and to
10% or  less of  the Trust's  total assets  in all  such obligations  or in  all
illiquid assets, in the aggregate;
 
COMMERCIAL PAPER--
 
commercial  paper  rated within  the  two highest  grades  by Standard  & Poor's
Corporation ("S&P") or  the highest  grade by Moody's  Investors Service,  Inc.,
("Moody's")  or, if not  rated, issued by  a company having  an outstanding debt
issue rated at least AA by S&P or Aa by Moody's;
 
CORPORATE OBLIGATIONS--
 
corporate obligations, rated at least A by S&P or Moody's, maturing in one  year
or less.
 
    See  the  Appendix  to  the  Statement  of  Additional  Information  for  an
explanation of S&P and Moody's ratings.
 
REPURCHASE AGREEMENTS--
 
    The Trust may  enter into repurchase  agreements, which may  be viewed as  a
type  of  secured  lending  by  the  Trust,  and  which  typically  involve  the
acquisition by the Trust of debt securities from a selling financial institution
such as a  bank, savings and  loan association or  broker-dealer. The  agreement
provides  that  the  Trust will  sell  back  to the  institution,  and  that the
institution  will  repurchase,  the  underlying  security  ("collateral")  at  a
specified  price  and at  a  fixed time  in the  future.  The Trust  will accrue
interest from the institution  until the time when  the repurchase is to  occur.
Although  such  date  is deemed  by  the Trust  to  be  the maturity  date  of a
repurchase  agreement,  the  maturities  of  securities  subject  to  repurchase
agreements  are not subject to any limits  and may exceed thirteen months. While
repurchase  agreements  involve  certain   risks  not  associated  with   direct
investments  in  debt  securities,  the  Trust  follows  procedures  designed to
minimize such risks. These procedures include effecting repurchase  transactions
only  with large,  well-capitalized and  well-established financial institutions
and specifying the required value of the collateral underlying the agreement.
 
    The investment  objectives and  policies  stated above  may not  be  changed
without  shareholder approval. There is no assurance that the Trust's objectives
will be achieved.
 
PORTFOLIO MANAGEMENT--
 
    Although the  Trust  will  generally not  seek  profits  through  short-term
trading,  it may dispose of any portfolio  security prior to its maturity if, on
the basis of a revised credit evaluation of the issuer or other circumstances or
considerations, it believes such disposition advisable.
 
                                       4
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
    The Trust is expected  to have a  high portfolio turnover  due to the  short
maturities  of securities  purchased, but this  should not affect  income or net
asset value as brokerage commissions are not normally charged on the purchase or
sale of money market instruments.
 
    The Trust will  attempt to balance  its objectives of  high current  income,
capital  preservation  and  liquidity  by  investing  in  securities  of varying
maturities and risks.  The Trust will  not, however, invest  in securities  that
mature in more than one year from the date of purchase.
 
    VARIABLE  RATE  AND  FLOATING  RATE OBLIGATIONS.  Certain  of  the  types of
investments described above may be  variable rate or floating rate  obligations.
The interest rates payable on variable rate or floating rate obligations are not
fixed  and may fluctuate based  upon changes in market  rates. The interest rate
payable on a variable  rate obligation may be  adjusted either at  predesignated
periodic  intervals and on a floating rate obligation whenever there is a change
in the market rate of interest on which the interest rate payable is based.
 
    BROKERAGE ALLOCATION.  Brokerage commissions are not normally charged on the
purchase or sale of money market instruments, but such transactions may  involve
transaction  costs in the form of spreads between bid and asked prices. Although
the Trust is expected to  have a high portfolio turnover  rate due to the  short
maturities  of its  portfolio securities,  the Trust's  income or  the net asset
value of  its shares  should not  be affected  as brokers'  commissions are  not
normally  incurred.  Pursuant  to  an  order  of  the  Securities  and  Exchange
Commission, the Trust may effect principal transactions in certain money  market
instruments  with  Dean  Witter.  In addition,  the  Trust  may  incur brokerage
commissions on transactions conducted through Dean Witter.
 
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    The investment restrictions  listed below  are among  the restrictions  that
have  been  adopted by  the  Trust as  fundamental  policies. Under  the  Act, a
fundamental policy may  not be changed  without the  vote of a  majority of  the
outstanding voting securities of the Trust, as defined in the Act.
 
    These restrictions provide that the Trust may not:
 
    1.   Borrow  money, except from  banks for temporary  or emergency purposes,
including the meeting of redemption  requests which might otherwise require  the
untimely  disposition of securities.  Borrowing in the  aggregate may not exceed
20%, and borrowing for purposes other than meeting redemptions may not exceed 5%
of the value of the Trust's  total assets (including the amount borrowed),  less
liabilities  (not including  the amount borrowed)  at the time  the borrowing is
made;
 
    2.  Purchase securities of any issuer, except for securities issued by  U.S.
Government  agencies  or  instrumentalities,  having  a  record,  together  with
predecessors, of less  than three years'  continuous operation, if,  immediately
after such purchase, more than 5% of the value of the Trust's total assets would
be invested in such securities;
 
    3.   Purchase any securities, other than obligations of the U.S. Government,
or its agencies or instrumentalities, if, immediately after such purchase,  more
than 5% of the value of the Trust's total assets would be invested in securities
of  any one issuer, or more than 10% of the outstanding securities of one issuer
would be owned  by the Trust  (for this  purpose all indebtedness  of an  issuer
shall be deemed a single class of security); and
 
    4.   Purchase any securities, other than obligations of banks or of the U.S.
Government, or its  agencies or  instrumentalities, if,  immediately after  such
purchase,  more  than 25%  of the  value of  the Trust's  total assets  would be
invested in the securities of issuers in the same industry; however, there is no
limitation as to  investments in bank  obligations or in  obligations issued  or
guaranteed by the Federal Government or its agencies or instrumentalities.
 
    If a percentage restriction is adhered to at the time of investment, a later
increase  or  decrease  in  percentage  resulting from  a  change  in  values of
portfolio securities or amount of total or  net assets will not be considered  a
violation of any of the foregoing restrictions.
 
                                       5
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
 
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                          <C>
ASSETS:
Investments in securities, at value
  (amortized cost $7,160,110,336)..........  $7,160,110,336
Cash.......................................           7,044
Interest receivable........................      13,060,782
Prepaid expenses and other assets..........          98,115
                                             --------------
        TOTAL ASSETS.......................   7,173,276,277
                                             --------------
LIABILITIES:
Payable for:
  Investment management fee................       1,641,346
  Plan of distribution fee.................         557,085
  Shares of beneficial interest
    repurchased............................           1,953
Accrued expenses and other payables........         932,603
                                             --------------
        TOTAL LIABILITIES..................       3,132,987
                                             --------------
NET ASSETS:
Paid-in-capital............................   7,170,136,722
Accumulated undistributed net investment
  income...................................           6,568
                                             --------------
        NET ASSETS.........................  $7,170,143,290
                                             --------------
                                             --------------
NET ASSET VALUE PER SHARE, 7,170,136,722
 shares outstanding (unlimited shares
 authorized of $.01 par value).............
                                                      $1.00
                                             --------------
                                             --------------
</TABLE>
    
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                            <C>
NET INVESTMENT INCOME:
INTEREST INCOME..............................  $ 376,507,894
                                               -------------
EXPENSES
  Investment management fee..................     19,802,633
  Plan of distribution fee...................      6,495,409
  Transfer agent fees and expenses...........      3,112,938
  Registration fees..........................      1,274,800
  Custodian fees.............................        278,338
  Shareholder reports and notices............        205,750
  Professional fees..........................         58,233
  Trustees' fees and expenses................         17,465
  Other......................................         68,425
                                               -------------
      TOTAL EXPENSES.........................     31,313,991
                                               -------------
      NET INVESTMENT INCOME AND
        NET INCREASE.........................  $ 345,193,903
                                               -------------
                                               -------------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                   JUNE 30, 1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income......................................................   $    345,193,903    $    255,626,693
    Net realized gain..........................................................          --                     92,427
                                                                                 ------------------  ------------------
        Net increase...........................................................        345,193,903         255,719,120
                                                                                 ------------------  ------------------
  Dividends and distributions from:
    Net investment income......................................................       (345,191,836)       (255,627,418)
    Net realized gain..........................................................          --                    (92,427)
                                                                                 ------------------  ------------------
        Total..................................................................       (345,191,836)       (255,719,845)
                                                                                 ------------------  ------------------
    Net increase from transactions in shares of beneficial interest............      1,461,230,225       1,564,838,536
                                                                                 ------------------  ------------------
        Total increase.........................................................      1,461,232,292       1,564,837,811
NET ASSETS:
  Beginning of period..........................................................      5,708,910,998       4,144,073,187
                                                                                 ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $6,568 and
   $4,501, respectively).......................................................   $  7,170,143,290    $  5,708,910,998
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       6
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION  AND  ACCOUNTING  POLICIES--Active  Assets  Money  Trust (the
"Trust") is registered under the Investment Company Act of 1940, as amended (the
"Act"), as a  diversified, open-end management  investment company. The  Trust's
investment  objective  is  high  current  income,  preservation  of  capital and
liquidity. The Trust was  organized as a Massachusetts  business trust on  March
30, 1981 and commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that affect  the reported  amounts and  disclosures. Actual results
could differ from  those estimates. The  following is a  summary of  significant
accounting policies:
 
    A.   VALUATION OF INVESTMENTS--Portfolio  securities are valued at amortized
    cost, which approximates market value.
 
    B.  ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for  on
    the  trade date (date the order to  buy or sell is executed). Realized gains
    and losses on security  transactions are determined  by the identified  cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.   FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies and to distribute all of its taxable and nontaxable income to  its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement with Dean  Witter InterCapital  Inc. (the  "Investment Manager"),  the
Trust  pays the Investment  Manager a management fee,  accrued daily and payable
monthly, by applying the following annual rates  to the net assets of the  Trust
determined  as of the  close of each business  day: 0.50% to  the portion of the
daily net assets not exceeding $500 million; 0.425% to the portion of the  daily
net  assets exceeding $500 million but not exceeding $750 million; 0.375% to the
portion of the  daily net  assets exceeding $750  million but  not exceeding  $1
billion;  0.35% to the portion of the  daily net assets exceeding $1 billion but
not exceeding  $1.5 billion;  0.325% to  the  portion of  the daily  net  assets
exceeding $1.5 billion but not exceeding $2 billion; 0.30% to the portion of the
daily  net assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% to
the portion of the daily net assets exceeding $2.5 billion but not exceeding  $3
billion; and 0.25% to the portion of the daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the   Trustees    determine   to    reimburse,   as    described   below.    The
 
                                       7
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
following  activities and services may be  provided by the Distributor and other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average daily net assets. For the year ended June 30, 1996, the distribution fee
was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases and proceeds  from sales/maturities  of portfolio  securities for  the
year  ended  June  30,  1996  aggregated  $23,586,285,233  and  $22,455,376,131,
respectively.
 
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $236,000.
 
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent  Trustees  of  the  Trust  who  will  have  served as
independent Trustees for at least five years at the time of retirement. Benefits
under this plan are based on years  of service and compensation during the  last
five  years of service. Aggregate pension costs for the year ended June 30, 1996
included in Trustees' fees and expenses in the Statement of Operations  amounted
to  $1,238. At  June 30,  1996, the  Trust had  an accrued  pension liability of
$48,883 which is  included in accrued  expenses in the  Statement of Assets  and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                   JUNE 30, 1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
Shares sold....................................................................      26,645,844,853      21,295,444,660
Shares issued in reinvestment of dividends.....................................         344,415,057         255,223,533
                                                                                 ------------------  ------------------
                                                                                     26,990,259,910      21,550,668,193
Shares repurchased.............................................................     (25,529,029,685)    (19,985,829,657)
                                                                                 ------------------  ------------------
Net increase in shares outstanding.............................................       1,461,230,225       1,564,838,536
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
    
 
6.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
 
                                       8
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
COMMERCIAL PAPER (76.6%)
                          AUTOMOTIVE - FINANCE (6.5%)
$  121,150   Ford Motor Credit Co.
              07/12/96 - 10/11/96......  5.36 - 5.53  % $   120,550,912
   345,650   General Motors Acceptance
              Corp. 07/02/96 -
              01/17/97.................  5.07 - 5.67        341,847,614
                                                        ---------------
                                                            462,398,526
                                                        ---------------
BANK HOLDING COMPANIES (13.7%)
   180,300   BankAmerica Corp. 07/30/96
              - 11/18/96...............  5.23 - 5.48        178,351,622
   150,000   Chase Manhattan Corp.
              09/10/96 - 12/30/96......  5.44 - 5.47        147,566,778
    20,000   Corestates Capital Corp.
              07/16/96.................      5.15            19,952,306
   105,000   Fleet Financial Group,
              Inc. 07/08/96 -
              08/08/96.................  5.37 - 5.39        104,683,350
    70,000   Mellon Financial Co.
              08/07/96.................      5.38            69,595,808
   320,000   Morgan (J.P.) & Co. Inc.
              08/01/96 - 12/20/96......  5.00 - 5.62        316,608,272
    30,000   NationsBank Corp.
              09/27/96.................      5.46            29,600,250
    67,850   PNC Funding Corp. 08/12/96
              - 09/17/96...............  5.47 - 5.49         67,237,469
    50,000   Republic New York Corp.
              07/12/96.................      5.05            49,910,805
                                                        ---------------
                                                            983,506,660
                                                        ---------------
BANKS - COMMERCIAL (27.6%)
   359,400   Abbey National North
              America Corp.
              08/09/96 - 12/26/96......  5.00 - 5.65        352,786,118
   237,890   ABN-AMRO North America
              Finance Inc. 08/23/96 -
              12/20/96.................  5.00 - 5.50        234,578,741
   240,000   Canadian Imperial Holdings
              Inc.
              07/08/96 - 09/13/96......  5.35 - 5.52        237,777,503
    33,475   Commerzbank U.S. Finance
              Inc. 08/13/96............      5.36            33,253,646
   295,000   Deutsche Bank Financial
              Inc. 07/19/96 -
              12/31/96.................  4.97 - 5.62        291,696,197
   182,850   Dresdner U.S. Finance Inc.
              07/22/96 - 12/09/96......  5.05 - 5.56        180,394,941
    95,000   International Nederlanden
              (U.S.) Funding Corp.
              07/09/96.................      5.34            94,860,931
   145,000   National Australia Funding
              (DE) Inc. 08/05/96 -
              11/07/96.................  5.14 - 5.50        143,524,856
    30,000   SBC Finance (DE) Inc.
              12/27/96.................      5.64            29,173,433
 
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
 $ 210,000   Toronto-Dominion Holdings
              USA Inc. 07/11/96 -
              12/02/96.................   5.33 - 5.50%  $   207,738,700
   153,000   Union Commercial Funding
              Corp.
              07/23/96 - 11/05/96......   5.39 - 5.49       151,106,144
    19,800   WestPac Capital Corp.
              12/05/96.................      5.66            19,319,025
                                                        ---------------
                                                          1,976,210,235
                                                        ---------------
BROKERAGE (4.3%)
   230,800   Goldman Sachs Group L.P.
              07/15/96 - 09/24/96......   5.34 - 5.45       229,380,311
    80,000   Morgan Stanley Group, Inc.
              07/09/96 - 07/18/96......   5.33 - 5.34        79,816,319
                                                        ---------------
                                                            309,196,630
                                                        ---------------
                           CANADIAN GOVERNMENT (0.4%)
    25,000   British Columbia (Province
              of) 10/28/96.............      5.17            24,579,861
                                                        ---------------
CHEMICALS (0.3%)
    24,000   Monsanto Co. 08/22/96.....      5.37            23,809,920
                                                        ---------------
FINANCE - COMMERCIAL (2.5%)
   181,050   CIT Group Holdings, Inc.
              07/12/96 - 08/28/96......  5.31 - 5.43        180,250,119
                                                        ---------------
FINANCE - CONSUMER (5.5%)
   305,950   American Express Credit
              Corp.
              07/03/96 - 08/30/96......  5.13 - 5.77        305,051,328
    65,000   Avco Financial Services
              Inc. 07/08/96 -
              07/31/96.................  5.39 - 5.42         64,809,716
    27,000   Norwest Financial Inc.
              07/15/96.................      5.35            26,936,640
                                                        ---------------
                                                            396,797,684
                                                        ---------------
FINANCE - DIVERSIFIED (7.6%)
   199,000   Associates Corp. of
              North America
              07/24/96 - 10/09/96......  5.06 - 5.54        197,537,075
   354,690   General Electric Capital
              Corp.
              07/10/96 - 02/18/97......  5.14 - 5.82        349,674,892
                                                        ---------------
                                                            547,211,967
                                                        ---------------
FINANCE - EQUIPMENT (0.9%)
    66,150   Deere (John) Capital Corp.
              07/19/96 - 07/29/96......  5.34 - 5.38         65,887,828
                                                        ---------------
FOOD & BEVERAGES (0.6%)
    40,000   Coca-Cola Co. 07/25/96....      5.32            39,848,333
                                                        ---------------
INDUSTRIALS (0.2%)
    10,950   Motorola Inc. 08/12/96....      5.41            10,878,132
                                                        ---------------
</TABLE>
    
 
   
                                       9
    
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
OFFICE EQUIPMENT (2.7%)
 $  75,000   Hewlett-Packard Co.
              08/14/96 - 09/30/96......   5.26 - 5.45%  $    74,207,650
    90,000   IBM Credit Corp.
              08/19/96.................      5.42            89,315,325
    30,000   Xerox Credit Corp.
              07/29/96.................      5.34            29,868,000
                                                        ---------------
                                                            193,390,975
                                                        ---------------
                                        RETAIL (3.4%)
   247,800   Sears Roebuck Acceptance
              Corp. 07/11/96 -
              10/22/96.................  5.36 - 5.54        245,639,669
                                                        ---------------
TELEPHONES (0.4%)
    30,000   Ameritech Corp. 07/30/96..      5.33            29,864,892
                                                        ---------------
             TOTAL COMMERCIAL PAPER (AMORTIZED COST
              $5,489,471,431).........................    5,489,471,431
                                                        ---------------
SHORT-TERM BANK NOTES (12.8%)
    60,000   Bank of New York 08/23/96
              - 10/04/96...............  4.97 - 5.38         60,000,000
   259,500   F.C.C. National Bank
              07/03/96 - 09/12/96......  5.11 - 5.43        259,500,000
    55,000   First National Bank of
              Boston 07/31/96 -
              08/09/96.................  5.00 - 5.22         55,000,000
    50,000   First National Bank of
              Chicago 11/29/96.........      5.45            50,000,000
   354,000   First Union National Bank
              07/01/96 - 10/30/96......  5.00 - 5.47        354,000,000
    45,000   La Salle National Bank
              08/26/96.................      5.37            45,000,000
    95,000   NationsBank, N.A. 07/17/96
              - 08/01/96...............  5.35 - 5.48         95,000,000
                                                        ---------------
             TOTAL SHORT-TERM BANK NOTES (AMORTIZED
              COST $918,500,000)......................      918,500,000
                                                        ---------------
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
U.S. GOVERNMENT & AGENCIES OBLIGATIONS (5.2%)
 $  65,000   Federal Home Loan Banks
              07/10/96 - 01/31/97......   5.15 - 5.53%  $    64,293,638
   195,000   Federal National Mortgage
              Assoc. 08/29/96 -
              10/10/96.................   5.25 - 5.42       192,878,818
   115,000   U.S. Treasury Bills
              07/25/96 - 03/06/97......   5.14 - 5.71       112,374,654
                                                        ---------------
             TOTAL U.S. GOVERNMENT & AGENCIES
              OBLIGATIONS
              (AMORTIZED COST $369,547,110)...........      369,547,110
                                                        ---------------
CERTIFICATES OF DEPOSIT (3.1%)
    45,000   Chase Manhattan Bank (USA)
              09/20/96.................      5.40            45,000,000
   180,000   Union Bank 09/12/96 -
              11/19/96.................  5.45 - 5.55        180,000,000
                                                        ---------------
             TOTAL CERTIFICATES OF DEPOSIT (AMORTIZED
              COST $225,000,000)......................      225,000,000
                                                        ---------------
BANKERS' ACCEPTANCES (2.2%)
    33,000   Chase Manhattan Bank
              09/09/96 - 11/26/96......  5.45 - 5.55         32,433,600
    42,000   Chemical Bank
              07/30/96 - 08/19/96......  5.32 - 5.33         41,722,407
    62,500   Corestates Bank, N.A.
              08/08/96 - 11/08/96......  5.37 - 5.41         61,806,731
    10,000   First Bank, N.A.
              10/11/96.................      5.43             9,847,177
    12,000   Morgan Guaranty Tr. Co. of
              NY 10/30/96..............      5.46            11,781,880
                                                        ---------------
             TOTAL BANKERS' ACCEPTANCES (AMORTIZED
              COST $157,591,795)......................      157,591,795
                                                        ---------------
</TABLE>
    
 
   
<TABLE>
<S>                                            <C>      <C>
TOTAL INVESTMENTS (AMORTIZED COST
  $7,160,110,336) (A)........................   99.9 %   7,160,110,336
CASH AND OTHER ASSETS IN EXCESS OF
  LIABILITIES................................    0.1        10,032,954
                                               ------   --------------
NET ASSETS...................................  100.0 %  $7,170,143,290
                                               ------   --------------
                                               ------   --------------
<FN>
- -------------
(A) COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       10
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets Money Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material respects, the financial position of Active Assets Money Trust (the
"Trust") at June  30, 1996,  the results  of its  operations for  the year  then
ended,  the changes in  its net assets for  each of the two  years in the period
then ended and the financial highlights for each of the ten years in the  period
then  ended, in conformity with  generally accepted accounting principles. These
financial  statements  and  financial  highlights  (hereafter  referred  to   as
"financial  statements") are the  responsibility of the  Trust's management; our
responsibility is to express an opinion  on these financial statements based  on
our  audits. We conducted our audits of these financial statements in accordance
with generally  accepted  auditing standards  which  require that  we  plan  and
perform  the audit  to obtain reasonable  assurance about  whether the financial
statements are free of material misstatement. An audit includes examining, on  a
test  basis, evidence  supporting the amounts  and disclosures  in the financial
statements, assessing the accounting  principles used and significant  estimates
made by management, and evaluating the overall financial statement presentation.
We  believe that our  audits, which included confirmation  of securities at June
30, 1996 by correspondence  with the custodian, provide  a reasonable basis  for
the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                                       11
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
                          ACTIVE ASSETS TAX-FREE TRUST
       TWO WORLD TRADE CENTER, NEW YORK, NEW YORK 10048 - (212) 392-5000
 
    Active  Assets Tax-Free  Trust (the  "Tax-Free Trust"  or the  "Trust") is a
no-load, diversified  open-end  management  investment  company.  The  Trust  is
authorized  to  reimburse Dean  Witter Distributors  Inc. for  specific expenses
incurred in promoting the distribution of the Trust's shares pursuant to a  Plan
of Distribution pursuant to Rule 12b-1 under the Investment Company Act of 1940,
as  amended (the "Act"). Reimbursement may in no event exceed an amount equal to
payments at the  annual rate of  0.15% of the  average daily net  assets of  the
Trust.
 
    The investment objective of the Tax-Free Trust is to provide as high a level
of  daily income exempt from  federal personal income tax  as is consistent with
stability of principal and liquidity. The  Trust seeks to achieve its  objective
by  investing primarily in  high quality, tax-exempt  securities with short-term
maturities including Municipal Bonds,  Municipal Notes and Municipal  Commercial
Paper.
 
    AN  INVESTMENT IN THE  TRUST IS NEITHER  INSURED NOR GUARANTEED  BY THE U.S.
GOVERNMENT. THERE IS  NO ASSURANCE THAT  THE TRUST  WILL BE ABLE  TO MAINTAIN  A
STABLE NET ASSET VALUE OF $1.00 PER SHARE.
 
    SHARES  OF THE TRUST  ARE NOT DEPOSITS  OR OBLIGATIONS OF,  OR GUARANTEED OR
ENDORSED BY, ANY BANK, AND THE SHARES  ARE NOT FEDERALLY INSURED BY THE  FEDERAL
DEPOSIT INSURANCE CORPORATION, THE FEDERAL RESERVE BOARD, OR ANY OTHER AGENCY.
                               TABLE OF CONTENTS
 
   
<TABLE>
<S>                                                 <C>
Highlights/2                                        How Net Asset Value is Determined/A-4
Summary of Trust Expenses/3                         Confirmations/A-5
Financial Highlights/3                              The Trusts and Their Management/A-5
Investment Objective and Policies/4                 Plan of Distribution/A-6
Investment Restrictions/7                           Dividends, Distributions and Taxes/A-6
Financial Statements -- June 30, 1996/8             General Information/A-9
Report of Independent Accountants/17                Voting Rights/A-9
Purchase and Redemption of Shares/A-1               Custodian/A-10
    Purchase of Shares/A-1                          Shareholder Inquiries/A-10
    Purchase of Shares by Non-Participants in
     the Active Assets Program/A-2
    Redemption of Shares/A-3
    Redemption of Shares by Non-Participants in
    the Active Assets Program/A-4
</TABLE>
    
 
   
    THIS  PROSPECTUS SETS FORTH CONCISELY THE INFORMATION YOU SHOULD KNOW BEFORE
INVESTING IN THE  TRUST. IT SHOULD  BE READ AND  RETAINED FOR FUTURE  REFERENCE.
ADDITIONAL  INFORMATION  ABOUT  THE  TRUST  IS  CONTAINED  IN  THE  STATEMENT OF
ADDITIONAL INFORMATION, DATED  AUGUST 22, 1996,  WHICH HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION, AND WHICH  IS AVAILABLE AT  NO CHARGE UPON
REQUEST OF THE  TRUST AT  THE ADDRESS  LISTED ABOVE  OR BY  CALLING DEAN  WITTER
INTERCAPITAL   INC.  (THE  "INVESTMENT  MANAGER"  OR  "INTERCAPITAL")  AT  (212)
392-2550. THE  STATEMENT OF  ADDITIONAL INFORMATION  IS INCORPORATED  HEREIN  BY
REFERENCE.
    
 
    THE  INFORMATION IN THIS  PROSPECTUS SHOULD BE READ  IN CONJUNCTION WITH THE
INFORMATION APPEARING ELSEWHERE IN THIS DOCUMENT, INCLUDING THE APPENDIX HERETO,
WHICH IS PART OF THIS PROSPECTUS, AND IN THE DEAN WITTER CLIENT AGREEMENT.
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
    EXCHANGE COMMISSION OR  ANY STATE SECURITIES  COMMISSION NOR HAS  THE
       SECURITIES  AND EXCHANGE  COMMISSION OR  ANY STATE SECURITIES
            COMMISSION  PASSED   UPON  THE   ACCURACY  OR   ADEQUACY
                 OF  THIS PROSPECTUS. ANY REPRESENTATION TO THE
                           CONTRARY IS A CRIMINAL OFFENSE.
                            ------------------------
 
   
                THE DATE OF THIS PROSPECTUS IS AUGUST 22, 1996.
    
 
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
HIGHLIGHTS
 
   
<TABLE>
<S>                    <C>
THE                    A  no-load, open-end diversified management investment  company investing principally in short-term
TRUST                  securities exempt  from federal  income  tax. The  Trust is  authorized  to reimburse  Dean  Witter
                       Distributors  Inc. for  specific expenses  incurred in  promoting the  distribution of  the Trust's
                       shares pursuant to a Plan of Distribution pursuant to Rule 12b-1 under the Act (See page A-6).  The
                       Trust  is organized as an unincorporated business trust  under the laws of Massachusetts. (See page
                       A-5).
- ------------------------------------------------------------------------------------------------------------------------
SHARES                 The shares of the Tax-Free Trust are offered  to participants in the Active Assets program of  Dean
OFFERED                Witter  and to non-participants who wish to invest directly in shares of the Trust. (See page A-2).
                       The primary components of the Active Assets program are the Securities Account, which is linked  to
                       the  Active Assets Insured Account,  the Active Assets Money Trust,  the Tax-Free Trust, the Active
                       Assets California Tax-Free Trust or the Active  Assets Government Securities Trust and to the  Visa
                       Account. See the Dean Witter Client Agreement for further information.
- ------------------------------------------------------------------------------------------------------------------------
PURCHASE               Pursuant to the Dean Witter Client Agreement between Dean Witter and the customer, free credit cash
OF SHARES              balances  will be automatically  invested daily in shares  of the Trust at  their current net asset
                       value without any sales charge. Dean Witter Distributors  Inc. is the Distributor of shares of  the
                       Trust.  Investments  in shares  are  made under  the  circumstances described  under  "Purchase and
                       Redemption of Shares" (see page A-1). Non-participants in the Active Assets program should refer to
                       the discussion appearing at page A-2.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             High level of daily  tax-exempt income consistent  with stability of  principal and liquidity  (see
OBJECTIVE              page 4). There can be no assurance that the Trust's investment objective will be achieved.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             A diversified portfolio of tax-exempt, fixed-income securities with short-term maturities (see page
POLICY                 4).
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             Dean  Witter  InterCapital  Inc.,  the  Investment  Manager  of  the  Trust,  and  its wholly-owned
MANAGER                subsidiary, Dean Witter Services Company, Inc.,  serve in various investment management,  advisory,
                       management  and administrative  capacities to ninety-eight  investment companies  with assets under
                       management of approximately $84.6 billion at June 30, 1996 (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
MANAGEMENT             Monthly fee at an annual rate of 1/2 of 1% of average daily net assets, scaled down on assets  over
FEE                    $500 million (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
DISTRIBUTOR            Dean  Witter Distributors Inc.  (the "Distributor") sells  shares of the  Trust through Dean Witter
                       Reynolds Inc.  Other  than  the  reimbursement  to the  Distributor  pursuant  to  the  Rule  12b-1
                       Distribution Plan, the Distributor receives no distribution fees (see page A-2).
- ------------------------------------------------------------------------------------------------------------------------
PLAN OF                The  Trust is authorized to  reimburse specific expenses incurred  in promoting the distribution of
DISTRIBUTION           the Trust's shares pursuant to a Plan of  Distribution with the Distributor pursuant to Rule  12b-1
                       under  the Investment Company Act of 1940. Reimbursement may  in no event exceed an amount equal to
                       payments at the annual rate of 0.15 of 1% of average daily net assets of the Trust (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
DIVIDENDS              Automatically reinvested daily in additional shares at net asset value (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
REPORTS                Individual monthly account statements  from Dean Witter on  the Dean Witter Transaction  Statement;
                       annual and semi-annual Trust financial statements.
- ------------------------------------------------------------------------------------------------------------------------
REDEMPTION             For  participants in the Active Assets  program, shares of the Trust  will be redeemed at net asset
OF SHARES              value automatically to satisfy debit balances in the Securities Account created by activity therein
                       or to satisfy amounts owing in the Visa  Account resulting from Visa card purchases, cash  advances
                       or  checks written against the  Visa Account. Non-participants in  the Active Assets program should
                       refer to the discussion  appearing at page  A-4. It is  anticipated that the  net asset value  will
                       remain  constant at $1.00 per share. Dean Witter  has the right to terminate a shareholder's Active
                       Assets service,  in  which  event  all  Trust  shares held  in  a  shareholder's  account  will  be
                       involuntarily  redeemed. The Trust  also reserves the right  to reduce the number  of shares in all
                       accounts if the Trustees determine that this is necessary to maintain the constant $1.00 per  share
                       net asset value. See "Purchase and Redemption of Shares" (page A-1).
- ------------------------------------------------------------------------------------------------------------------------
RISKS                  The  Trust  invests  principally in  high  quality,  short-term fixed-income  securities  issued or
                       guaranteed by state and local governments which are  subject to minimal risk of loss of income  and
                       principal. However, the investor is directed to the discussions of "lease obligations" (page 5) and
                       "When-Issued  and Delayed Delivery Securities"  (page 6) concerning the  risks associated with such
                       portfolio securities and management techniques.
- ------------------------------------------------------------------------------------------------------------------------
    THE SUMMARY INFORMATION ABOVE SHOULD BE READ IN CONJUNCTION WITH THE DETAILED INFORMATION APPEARING ELSEWHERE IN  THIS
PROSPECTUS,  INCLUDING THE APPENDIX HERETO, IN THE DEAN WITTER CLIENT AGREEMENT AND IN THE TRUST'S STATEMENT OF ADDITIONAL
INFORMATION, INCLUDING THE APPENDIX THERETO.
</TABLE>
    
 
                                       2
 
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
SUMMARY OF TRUST EXPENSES
- --------------------------------------------------------------------------------
 
    The  following table illustrates all expenses and fees that a shareholder of
the Trust will incur. The expenses and fees  set forth in the table are for  the
fiscal year ended June 30, 1996.
 
<TABLE>
<S>                                       <C>
SHAREHOLDER TRANSACTION EXPENSES
Maximum Sales Charge Imposed on
 Purchases..............................    None
Maximum Sales Charge Imposed on
 Reinvested Dividends...................  None
Deferred Sales Charge...................  None
Redemption Fees.........................  None
Exchange Fee............................  None
ANNUAL TRUST OPERATING EXPENSES (AS A
 PERCENTAGE OF AVERAGE NET ASSETS)
Management Fees.........................    0.41%
12b-1 Fees..............................    0.10%
Other Expenses..........................    0.04%
                                          -------
Total Trust Operating Expenses..........    0.55%
                                          -------
                                          -------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                          10
EXAMPLE                                   1 YEAR    3 YEARS   5 YEARS    YEARS
                                          -------   -------   -------   -------
<S>                                       <C>       <C>       <C>       <C>
You would pay the following expenses on
 a $1,000 investment, assuming (1) 5%
 annual return and (2) redemption at the
 end of each time period:                   $ 6       $18       $31       $68
</TABLE>
 
    Dean Witter charges an annual Active Assets program participation fee of $80
($100 for corporate participants). Shareholders of the Trust who are not program
participants will not be charged an Active Assets program fee.
 
    The  above  example should  not be  considered a  representation of  past or
future expenses or performance. Actual expenses  of the Trust may be greater  or
less than those shown.
 
    The  purpose of this  table is to  assist the investor  in understanding the
various costs and expenses that an investor  in the Trust will bear directly  or
indirectly.  For a  more complete description  of these costs  and expenses, see
pages A-5 and A-6 in the Appendix to this Prospectus.
 
FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------
 
   
    The following ratios and per share  data for a share of beneficial  interest
outstanding  throughout each period  have been audited  by Price Waterhouse LLP,
independent accountants. The financial highlights should be read in  conjunction
with  the financial statements  and notes thereto and  the unqualified report of
independent accountants which  are contained  in this  Prospectus commencing  on
page 8.
    
 
   
<TABLE>
<CAPTION>
                                                                   FOR THE YEAR ENDED JUNE 30,
                                -------------------------------------------------------------------------------------------------
                                 1996      1995      1994      1993      1992      1991      1990      1989      1988      1987
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
<S>                             <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>
PER SHARE OPERATING PERFORMANCE:
Net asset value, beginning of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net investment income.........   0.031     0.030     0.020     0.021     0.033     0.047     0.054     0.056     0.043     0.039
Less dividends from net
 investment income............  (0.031)   (0.030)   (0.020)   (0.021)   (0.033)   (0.047)   (0.054)   (0.056)   (0.043)   (0.039)
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net asset value, end of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
TOTAL INVESTMENT RETURN+......    3.12%     3.09%     2.01%     2.15%     3.38%     4.84%     5.57%     5.77%     4.45%     4.00%
RATIOS TO AVERAGE NET ASSETS:
  Expenses....................    0.55%     0.56%     0.56%     0.57%     0.59%     0.60%     0.56%     0.58%     0.57%     0.58%
  Net investment income.......    3.08%     3.05%     1.98%     2.13%     3.30%     4.71%     5.44%     5.66%     4.35%     3.89%
SUPPLEMENTAL DATA:
Net assets, end of period, in
 millions.....................  $1,542    $1,499    $1,416    $1,355    $1,304    $1,342    $1,174    $1,112    $1,034    $1,045
</TABLE>
    
 
- -------------
+  CALCULATED BASED ON  THE NET ASSET VALUE  AS OF THE LAST  BUSINESS DAY OF THE
PERIOD.
 
                                       3
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
INVESTMENT OBJECTIVE AND POLICIES
- --------------------------------------------------------------------------------
 
    THE INVESTMENT OBJECTIVE OF THE TRUST IS TO PROVIDE AS HIGH A LEVEL OF DAILY
INCOME  EXEMPT FROM FEDERAL PERSONAL INCOME  TAX AS IS CONSISTENT WITH STABILITY
OF PRINCIPAL AND  LIQUIDITY. It is  a fundamental  policy of the  Trust that  at
least  80% of its  total assets will  be invested in  securities the interest on
which is exempt from federal personal income tax ("tax-exempt securities"). This
policy and the Trust's investment objective may not be changed without a vote of
a majority of the Trust's outstanding voting securities (as defined in the Act).
There is no assurance that the objective will be achieved.
 
    The Trust seeks to achieve  its investment objective by investing  primarily
in   high  quality  tax-exempt  securities   with  short-term  maturities.  Such
securities  will  include  Municipal   Bonds,  Municipal  Notes  and   Municipal
Commercial Paper ("Municipal Obligations") with maturities of thirteen months or
less,  which are  rated in  one of  the two  highest rating  categories for debt
obligations  by   at  least   two  nationally   recognized  statistical   rating
organizations  ("NRSROs" -- primarily Moody's  Investors Service ("Moody's") and
Standard & Poor's Corporation ("S&P")), or one NRSRO if the obligation is  rated
by  only one NRSRO. Unrated obligations may  be purchased if they are determined
to be of comparable quality by the Trust's Trustees.
 
    Municipal Bonds and Municipal Notes are debt obligations of states,  cities,
municipalities  and municipal agencies  which generally have  maturities, at the
time of their issuance, of either one year or more (Bonds) or from six months to
three years (Notes). Municipal Commercial Paper refers to short-term obligations
of municipalities.
 
    The Trust  may purchase  certain Municipal  Obligations which  have a  final
maturity of more than thirteen months but which are subject to short-term demand
features  or tenders prior to final maturity, either determined by the issuer or
selected at  the  holder's  option.  The former  are  commonly  referred  to  as
"variable  rate" obligations (see below) and  the latter as municipal commercial
paper. The  Trust may  purchase Municipal  Bonds and  Notes if  they are  within
either  the short-term or long-term rating  levels set forth above for Municipal
Obligations.
 
    See  the  Appendix  to  the  Statement  of  Additional  Information  for  an
explanation of Moody's and S&P ratings.
 
    Any  municipal  obligation  which  depends  on  the  credit  of  the Federal
Government shall be considered to have a rating in the highest category.
 
    Up to 20%  of the Trust's  total assets  may be invested  in securities  the
interest  on  which is  not exempt  from federal  personal income  tax ("taxable
securities") and in  tax-exempt securities  subject to  the federal  alternative
minimum  tax for individual ("AMT") (tax-exempt  securities which are subject to
the AMT will not be included in  the 80% total referred to above for  investment
in tax-exempt securities).
 
    Up  to 20% of the Trust's total assets may be invested in taxable securities
of the type described below. The Trust  may temporarily invest more than 20%  in
taxable  securities  and  tax-exempt securities  subject  to AMT  to  maintain a
"defensive" posture  when, in  the  opinion of  the  Investment Manager,  it  is
advisable to do so because of market conditions. The types of taxable securities
in  which  the  Trust  may  invest  are  limited  to  the  following short-term,
fixed-income securities (maturing in  thirteen months or less  from the time  of
purchase):  (i) obligations  of the  United States  Government or  its agencies,
instrumentalities or  authorities;  (ii) prime  commercial  paper rated  P-1  by
Moody's or A-1 by S&P; (iii) certificates of deposit and banker's acceptances of
domestic banks with assets of $1 billion or more; and (iv) repurchase agreements
with respect to any of the foregoing portfolio securities.
 
                                       4
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
    The foregoing percentage and rating limita-
tions  apply at the time of acquisition of a security based on the last previous
determination of  the Trust's  net asset  value. Any  subsequent change  in  any
rating  by  a rating  service  or change  in  percentages resulting  from market
fluctuations or amount of total or net assets may not require elimination of any
security from the Trust's portfolio.
 
    The ratings assigned by NRSROs represent their opinions as to the quality of
the securities which they undertake to  rate. It should be emphasized,  however,
that  the ratings are general and not absolute standards of quality. However, in
accordance with procedures adopted by  the Trust's Trustees pursuant to  federal
securities regulations governing money market funds, the Investment Manager will
perform  a  creditworthiness  analysis  of  such  downgraded  securities,  which
analysis will be reported to the  Trustees who will, in turn, determine  whether
the securities continue to present minimal credit risks to the Trust.
 
    The  two  principal classifications  of  Municipal Obligations  are "general
obligation" and "revenue" bonds, notes  or commercial paper. General  obligation
bonds,  notes or  commercial paper  are secured  by the  issuer's pledge  of its
faith, credit  and taxing  power  for the  payment  of principal  and  interest.
Issuers  of general obligation bonds, notes or commercial paper include a state,
its counties, cities, towns and  other governmental units. Revenue bonds,  notes
or  commercial paper  are payable  from the  revenues derived  from a particular
facility or  class  of facilities  or,  in  some cases,  from  specific  revenue
sources.  Revenue bonds, notes or commercial paper are issued for a wide variety
of purposes, including the financing of  electric, gas, water and sewer  systems
and  other  public  utilities;  industrial  development  and  pollution  control
facilities;  single  and  multi-family  housing  units;  public  buildings   and
facilities;  air and marine ports, transportation facilities such as toll roads,
bridges and tunnels; and health and educational facilities such as hospitals and
dormitories. They rely primarily on user fees to pay debt service, although  the
principal  revenue source is often  supplemented by additional security features
which are intended to enhance the creditworthiness of the issuer's  obligations.
In  some cases, particularly revenue bonds  issued to finance housing and public
buildings, a direct or implied "moral obligation" of a governmental unit may  be
pledged  to the payment of debt service. In  other cases, a special tax or other
charge may augment user fees.
 
    Included within  the  revenue bonds  category  are participations  in  lease
obligations  or installment purchase  contracts (hereinafter collectively called
"lease obligations") of municipalities. State and local agencies or  authorities
issue lease obligations to acquire equipment and facilities.
 
    Lease  obligations  may  have  risks not  normally  associated  with general
obligation  or  other  revenue  bonds.  Leases,  and  installment  purchase   or
conditional  sale contracts (which may provide for  title to the leased asset to
pass eventually  to the  issuer), have  developed as  a means  for  governmental
issuers  to acquire  property and equipment  without the  necessity of complying
with the constitutional and statutory requirements generally applicable for  the
issuance  of debt. Certain lease obligations contain "non-appropriation" clauses
that provide  that the  governmental issuer  has no  obligation to  make  future
payments  under  the lease  or contract  unless money  is appropriated  for such
purpose by  the appropriate  legislative body  on an  annual or  other  periodic
basis.  Consequently,  continued  lease  payments  on  those  lease  obligations
containing "non-appropriation"  clauses  are  dependent  on  future  legislative
actions.  If such  legislative actions  do not occur,  the holders  of the lease
obligation may  experience  difficulty  in exercising  their  rights,  including
disposition of the property.
 
   
    Certain  lease  obligations have  not developed  the depth  of marketability
associated with more conventional municipal  obligations, and, as a result,  may
be  considered illiquid securities.  To determine whether or  not the Trust will
consider such securities to be illiquid (the Trust may not invest more than  ten
percent of its net assets in illiquid securi-
    
 
                                       5
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ties),  the Trustees of the Trust have  established guidelines to be utilized by
the Trust in determining the liquidity of a lease obligation. The factors to  be
considered  in making the determination include:  1) the frequency of trades and
quoted prices for the obligation; 2)  the number of dealers willing to  purchase
or  sell  the security  and the  number  of other  potential purchasers;  3) the
willingness of dealers to undertake to make a market in the security; and 4) the
nature of the marketplace trades, including,  the time needed to dispose of  the
security,  the method of  soliciting offers, and the  mechanics of the transfer.
All lease obligations purchased by the Trust are subject to the creditworthiness
standards discussed above for Municipal Obligations.
 
    The Trust does not  generally intend to  invest more than  25% of its  total
assets  in securities of governmental units located in any one state, territory,
or possession of the United  States. The Trust may invest  more than 25% of  its
total assets in industrial development and pollution control bonds (two kinds of
tax-exempt  Municipal Bonds) whether or not  the users of facilities financed by
such bonds are in the same industry. In  cases where such users are in the  same
industry,  there may be additional risk to the Trust in the event of an economic
downturn in such industry, which may result generally in a lowered need for such
facilities and  a lowered  ability of  such users  to pay  for the  use of  such
facilities.
 
    The  high quality,  short-term fixed  income securities  in which  the Trust
principally invests are issued and/or guaranteed by state and local  governments
and  their agencies and authorities  and are subject to  minimal risk of loss of
income and principal.
 
PORTFOLIO MANAGEMENT
 
    Although the Trust will generally acquire
securities for investment with the intent  of holding them to maturity and  will
not  seek  profits through  short-term  trading, the  Trust  may dispose  of any
security prior to its maturity to meet redemption requests. Securities may  also
be  sold when  the Trust's  Investment Manager  believes such  disposition to be
advisable on the  basis of  a revised  evaluation of  the issuer  or based  upon
relevant  market considerations.  There may  be occasions  when, as  a result of
maturities of portfolio securities or sales of Trust shares, or in order to meet
anticipated redemption requests, the  Trust may hold cash  which is not  earning
income.
 
    The  average weighted maturity of the portfolio will be 90 days or less. The
relatively short-term nature of the Trust  portfolio is expected to result in  a
lower yield than portfolios comprised of longer-term tax-exempt securities.
 
    VARIABLE  RATE AND FLOATING RATE OBLIGATIONS.  The interest rates payable on
certain Municipal Bonds  and Municipal  Notes are  not fixed  and may  fluctuate
based  upon  changes in  market rates.  Municipal obligations  of this  type are
called "variable rate" or "floating rate" obligations. The interest rate payable
on a variable rate  obligation is adjusted  at predesignated periodic  intervals
and on a floating rate obligation, whenever there is a change in the market rate
of interest on which the interest rate payable is based.
 
    WHEN-ISSUED   AND  DELAYED  DELIVERY  SECURITIES.  The  Trust  may  purchase
tax-exempt securities on a when-issued or delayed delivery basis; i.e., delivery
and payment can take place  a month or more after  the date of the  transaction.
These  securities are subject  to market fluctuation and  no interest accrues to
the purchaser prior to settlement. At the time the Trust makes the commitment to
purchase such securities, it will record the transaction and thereafter  reflect
the value, each day, of such security in determining its net asset value.
 
    BROKERAGE  ALLOCATION.   Brokerage commissions  are not  normally charged on
purchases and sales of short-term  municipal obligations, but such  transactions
may  involve transaction  costs in  the form  of spreads  between bid  and asked
prices. Pursuant to  an order  of the  Securities and  Exchange Commission,  the
Trust may effect principal transactions in certain money market instruments with
Dean  Witter.  In  addition,  the  Trust  may  incur  brokerage  commissions  on
transactions conducted through Dean Witter.
 
                                       6
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
   
    The investment restrictions  listed below  are among  the restrictions  that
have  been  adopted by  the  Trust as  fundamental  policies. Under  the  Act, a
fundamental policy may  not be changed  without the  vote of a  majority of  the
outstanding  voting securities of the Trust, as defined in the Act. For purposes
of the following limitations: (a) an "issuer" of a security is the entity  whose
assets  and revenues are committed  to the payment of  interest and principal on
that particular  security provided  that the  guarantee of  a security  will  be
considered  a separate  security and,  provided further,  that a  guarantee of a
security shall not be  deemed to be  a security issued by  the guarantor if  the
value  of all securities issued or guaranteed  by the guarantor and owned by the
Fund does not exceed  10% of the value  of the total assets  of the Fund; (b)  a
"taxable  security" is any security the interest  on which is subject to federal
income tax;  and  (c)  all  percentage limitations  apply  immediately  after  a
purchase  or initial  investment, and  any subsequent  change in  any applicable
percentage resulting from market fluctuations or  amount of total or net  assets
does not require elimination of any security from the portfolio.
    
 
    The Trust may not:
 
        1.    Invest more  than  5% of  the  value of  its  total assets  in the
    securities of any one issuer  (other than obligations issued, or  guaranteed
    by, the United States Government, its agencies or instrumentalities);
 
        2.  Purchase more than 10% of all outstanding taxable debt securities of
    any one issuer;
 
        3.   Invest more  than 25% of the  value of its  total assets in taxable
    securities of  issuers  in  any one  industry  (industrial  development  and
    pollution  control bonds are grouped into industries based upon the business
    in which the issuers of such obligations are engaged). This restriction does
    not  apply  to  obligations  issued  or  guaranteed  by  the  United  States
    Government  or its agencies  or instrumentalities or  to investments in bank
    obligations;
 
        4.  Invest  more than 5%  of the value  of its total  assets in  taxable
    securities  of issuers having a record,  together with predecessors, of less
    than three years of continuous  operation. This restriction shall not  apply
    to  any  obligation  of  the  United  States  Government,  its  agencies  or
    instrumentalities; and
 
        5.  Borrow money, except from banks for temporary or emergency purposes,
    including the meeting of redemption  requests which might otherwise  require
    the  untimely disposition of securities. Borrowing  in the aggregate may not
    exceed 20%, and borrowing  for purposes other  than meeting redemptions  may
    not  exceed 5%,  of the  value of  the Trust's  total assets  (including the
    amount borrowed), less  liabilities (not including  the amount borrowed)  at
    the time the borrowing is made.
 
                                       7
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                          <C>
ASSETS:
Investments in securities, at value
  (amortized cost $1,643,339,150)..........  $1,643,339,150
Cash.......................................       2,322,982
Interest receivable........................       7,426,219
Receivable from affiliate..................       2,849,017
Prepaid expenses and other assets..........          50,662
                                             --------------
        TOTAL ASSETS.......................   1,655,988,030
                                             --------------
LIABILITIES:
Payable for:
  Investments purchased....................     113,338,770
  Investment management fee................         505,007
  Plan of distribution fee.................         123,020
Accrued expenses and other payables........         134,104
                                             --------------
        TOTAL LIABILITIES..................     114,100,901
                                             --------------
NET ASSETS:
Paid-in-capital............................   1,541,888,167
Accumulated undistributed net investment
  income...................................           1,091
Accumulated net realized loss..............          (2,129)
                                             --------------
        NET ASSETS.........................  $1,541,887,129
                                             --------------
                                             --------------
NET ASSET VALUE PER SHARE, 1,541,888,167
 shares outstanding (unlimited shares
 authorized of $.01 par value).............
                                                      $1.00
                                             --------------
                                             --------------
</TABLE>
    
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                             <C>
NET INVESTMENT INCOME:
INTEREST INCOME...............................  $58,069,820
                                                -----------
EXPENSES
  Investment management fee...................    6,571,351
  Plan of distribution fee....................    1,560,662
  Transfer agent fees and expenses............      355,031
  Registration fees...........................      145,672
  Shareholder reports and notices.............       62,080
  Professional fees...........................       54,523
  Trustees' fees and expenses.................       17,381
  Custodian fees..............................       79,140
  Other.......................................       23,721
                                                -----------
      TOTAL EXPENSES BEFORE EXPENSE OFFSET....    8,869,561
      LESS: EXPENSE OFFSET....................      (72,184)
                                                -----------
      TOTAL EXPENSES AFTER EXPENSE OFFSET.....    8,797,377
                                                -----------
      NET INVESTMENT INCOME...................   49,272,443
  NET REALIZED GAIN...........................       67,452
                                                -----------
      NET INCREASE............................  $49,339,895
                                                -----------
                                                -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income........................................................   $    49,272,443    $    45,957,679
    Net realized gain............................................................            67,452          --
                                                                                   -----------------  -----------------
        Net increase.............................................................        49,339,895         45,957,679
 
    Dividends from net investment income.........................................       (49,272,477)       (45,956,910)
    Net increase from transactions in shares of beneficial interest..............        42,488,823         83,029,307
                                                                                   -----------------  -----------------
        Total increase...........................................................        42,556,241         83,030,076
NET ASSETS:
  Beginning of period............................................................     1,499,330,888      1,416,300,812
                                                                                   -----------------  -----------------
  END OF PERIOD (including undistributed net investment income of $1,091 and
   $1,125, respectively).........................................................   $ 1,541,887,129    $ 1,499,330,888
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       8
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION AND  ACCOUNTING POLICIES--Active  Assets Tax-Free  Trust (the
"Trust") is registered under the Investment Company Act of 1940, as amended (the
"Act"), as a  diversified, open-end management  investment company. The  Trust's
investment  objective is to provide a high level of daily income which is exempt
from federal income tax  consistent with stability  of principal and  liquidity.
The  Trust was organized as a Massachusetts business trust on March 30, 1981 and
commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that affect  the reported  amounts and  disclosures. Actual  results
could  differ from  those estimates. The  following is a  summary of significant
accounting policies:
 
    A.  VALUATION OF INVESTMENTS--Portfolio  securities are valued at  amortized
    cost, which approximates market value.
 
    B.   ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for on
    the trade date (date the order to  buy or sell is executed). Realized  gains
    and  losses on security  transactions are determined  by the identified cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.  FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with  the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies  and to distribute all of its taxable and nontaxable income to its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.   INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment  Management
Agreement  with Dean  Witter InterCapital  Inc. (the  "Investment Manager"), the
Trust pays the Investment  Manager a management fee,  accrued daily and  payable
monthly,  by applying the following annual rates  to the net assets of the Trust
determined as of the close of each  business day: 0.50% to the portion of  daily
net assets not exceeding $500 million; 0.425% to the portion of daily net assets
exceeding  $500 million but not exceeding $750 million; 0.375% to the portion of
daily net assets exceeding $750 million  but not exceeding $1 billion; 0.35%  to
the  portion of  daily net  assets exceeding $1  billion but  not exceeding $1.5
billion; 0.325% to the  portion of daily net  assets exceeding $1.5 billion  but
not  exceeding $2 billion; 0.30% to the portion of daily net assets exceeding $2
billion but  not exceeding  $2.5 billion;  0.275% to  the portion  of daily  net
assets  exceeding $2.5 billion  but not exceeding  $3 billion; and  0.25% to the
portion of daily net assets exceeding $3 billion.
 
    Under the  terms of  the  Agreement, in  addition  to managing  the  Trust's
investments,  the Investment Manager maintains certain  of the Trust's books and
records and furnishes, at its own expense, office space, facilities,  equipment,
clerical,  bookkeeping and certain  legal services and pays  the salaries of all
personnel, including officers of the Trust  who are employees of the  Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.   PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"), an
affiliate of the Investment  Manager, is the distributor  of the Trust's  shares
and,  in accordance with  a Plan of  Distribution (the "Plan")  pursuant to Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under the Plan,  the Distributor bears  the expense of  all promotional  and
distribution related activities on behalf of the Trust, except for expenses that
the   Trustees  determine  to  reimburse,  as  described  below.  The  following
activities  and  services  may  be   provided  by  the  Distributor  and   other
broker-dealers under the
 
                                       9
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
Plan:   (1)  compensation  to,  and  expenses  of,  the  Distributor  and  other
broker-dealers; (2) sales incentives and bonuses to sales representatives and to
marketing personnel in connection  with promoting sales  of the Trust's  shares;
(3)  expenses incurred in connection with promoting sales of the Trust's shares;
(4) preparing and distributing sales  literature; and (5) providing  advertising
and  promotional activities, including direct  mail solicitation and television,
radio, newspaper, magazine and other media advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average daily net assets. For the year ended June 30, 1996, the distribution fee
was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases and proceeds  from sales/maturities  of portfolio  securities for  the
year   ended  June  30,  1996   aggregated  $3,045,910,870  and  $2,956,347,425,
respectively.
 
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $24,000.
 
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent  Trustees  of  the  Trust  who  will  have  served as
independent Trustees for at least five years at the time of retirement. Benefits
under this plan are based on years  of service and compensation during the  last
five years of service. Aggregate pension costs for the year ended June 30, 1996,
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $1,238. At  June 30,  1996, the  Trust had  an accrued  pension liability  of
$48,883  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     5,666,091,760      5,690,475,533
Shares issued in reinvestment of dividends.......................................        49,272,477         45,956,910
                                                                                   -----------------  -----------------
                                                                                      5,715,364,237      5,736,432,443
Shares repurchased...............................................................    (5,672,875,414)    (5,653,403,136)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        42,488,823         83,029,307
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
   
6.   FEDERAL INCOME TAX  STATUS--During the year ended  June 30, 1996, the Trust
utilized all of its net capital loss carrryovers of approximately $59,000.
    
 
   
7.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
    
 
                                       10
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            SHORT-TERM VARIABLE RATE MUNICIPAL OBLIGATIONS (77.4%)
            ARIZONA
$   6,500   Maricopa County, Arizona Public Service Co 1994 Ser F.......          3.70%   07/01/96     $     6,500,000
            ARKANSAS
   20,000   Crossett, Georgia Pacific Corp Ser 1984.....................          3.25    07/08/96          20,000,000
            CALIFORNIA
            California Pollution Control Financing Authority,
   14,000     Pacific Gas & Electric Co Ser 1996 F......................          3.40    07/01/96          14,000,000
    5,900     Southern California Edison Co 1986 Ser A..................          3.45    07/01/96           5,900,000
   25,000   Riverside County, 1996-97 Ser B TRANs (WI)..................          3.00    07/08/96          25,000,000
            COLORADO
   11,500   Colorado Health Facilities Authority, Kaiser Permanente 1994
              Ser A.....................................................          3.40    07/08/96          11,500,000
            CONNECTICUT
   38,000   Connecticut Development Authority, Connecticut Light & Power
              Co
              1993 A Ser................................................          3.35    07/01/96          38,000,000
            Connecticut Special Assessment,
   30,000     Unemployment Compensation 1993 Ser C (FGIC)...............          3.90    07/01/96          30,000,000
   30,000     Unemployment Compensation 1993 Ser C (FGIC)...............          3.90    07/01/97          30,000,000
            FLORIDA
   15,000   Dade County, Water & Sewer Ser 1994 (FGIC)..................          3.30    07/08/96          15,000,000
            Dade County Industrial Development Authority,
   22,700     Dolphins Stadium Ser 1985 B & C...........................          3.35    07/08/96          22,700,000
    7,700     Florida Power & Light Co Ser 1993.........................          3.60    07/01/96           7,700,000
   11,200   Jacksonville Health Facilities Authority, Baptist Medical
              Center Ser 1993 (MBIA)....................................          3.65    07/01/96          11,200,000
    5,000   Orange County Housing Finance Authority, Single Family Ser
              1996 B (AMT)..............................................          3.65    04/01/97           5,000,000
   32,600   Volusia County Health Facilities Authority, Pooled Ser 1985
              (FGIC)....................................................          3.70    07/08/96          32,600,000
            GEORGIA
   10,000   Albany-Dougherty County Hospital Authority, Phoebe-Putney
              Memorial Hospital Ser 1991 (AMBAC)........................          3.40    07/08/96          10,000,000
   16,102   Georgia Municipal Association, Pool Ser 1990 COPs (MBIA)....          3.30    07/08/96          16,101,957
            HAWAII
            Hawaii Department of Budget & Finance,
    5,000     Kaiser Permanente Semiannual Tender Ser 1984 B............          3.20    09/01/96           5,000,000
   22,100     Queens Medical Center Ser 1985 B (FGIC)...................          3.10    07/08/96          22,100,000
            IDAHO
            Idaho Health Facilities Authority,
   20,000     Pooled Ser 1985...........................................          3.40    07/08/96          20,000,000
   12,910     St Luke's Regional Medical Center Ser 1995................          3.65    07/01/96          12,910,000
            ILLINOIS
            Chicago,
   24,900     Chicago O'Hare Int'l Airport 2nd Lien 1994 Ser B (AMT)....          3.50    07/08/96          24,900,000
   25,000     General Obligation Tender Notes Ser 1995 A................          3.65    10/31/96          25,000,000
</TABLE>
    
 
                                       11
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
$   5,900   Illinois Development Finance Authority, Palos Community
              Hospital Ser 1994.........................................          3.30%   07/08/96     $     5,900,000
            Illinois Health Facilities Authority,
    9,000     Gottlieb Health Resources Inc Ser 1990....................          3.35    07/08/96           9,000,000
   19,600     Highland Park Hospital Ser 1991 A (FGIC)..................          3.40    07/08/96          19,600,000
   22,500     Lutheran General Health Care System Ser 1985 B............          3.60    07/01/96          22,500,000
   12,100     Northwestern Memorial Hospital Ser 1995...................          3.65    07/01/96          12,100,000
   10,000     Parkside Development Corp Ser 1991........................          3.45    07/08/96          10,000,000
    3,640   Illinois Housing Development Authority, Homeowner Mtg 1995
              Subser E-2 (AMT)..........................................          3.75    09/03/96           3,640,000
            INDIANA
   17,000   Indiana Hospital Equipment Financing Authority, Ser 1985
              (MBIA)....................................................          3.55    07/08/96          17,000,000
            Petersburg,
    8,400     Indianapolis Power & Light Co Ser 1995 B (AMBAC)..........          3.30    07/08/96           8,400,000
    5,000     Indianapolis Power & Light Co Ser 1994 A (AMT)............          3.35    07/08/96           5,000,000
    5,000   Purdue University, Student Fee Ser 1995 K...................          3.30    07/08/96           5,000,000
            KENTUCKY
    7,000   Jamestown, Union Underwear Co 1983 Ser A....................          3.50    07/08/96           7,000,000
            LOUISIANA
   30,000   Louisiana Offshore Terminal Authority, LOOP Inc 1992 Ser
              A.........................................................          3.40    07/08/96          30,000,000
   23,200   New Orleans Aviation Board, Ser 1993 B (MBIA)...............          3.25    07/08/96          23,200,000
            MASSACHUSETTS
   15,000   Massachusetts Bay Transportation Authority, 1984 Ser A......          3.05    09/01/96          15,000,000
   29,500   Massachusetts Health & Educational Facilities Authority,
              Harvard University Ser 1985 I.............................          3.05    07/08/96          29,500,000
    6,100   Massachusetts Municipal Wholesale Electric Company, Power
              Supply 1994 Ser C.........................................          3.05    07/08/96           6,100,000
   14,800   Massachusetts Port Authority, Refg Ser 1995 A...............          3.50    07/01/96          14,800,000
            MICHIGAN
    3,000   Delta County Economic Development Corporation, Mead-Escanaba
              Paper Co Ser 1985 E.......................................          3.60    07/01/96           3,000,000
            MINNESOTA
    2,200   Beltrami County, Environmental Northwood Panelboard Co Ser
              1991......................................................          3.60    07/01/96           2,200,000
    8,500   Minneapolis & St Paul Housing & Redevelopment Authority,
              Childrens Health Care Ser 1995 B (CGIC)...................          3.75    07/01/96           8,500,000
   10,500   University of Minnesota Regents, Ser 1985 F.................          3.25    08/01/96          10,500,000
            MISSISSIPPI
    7,000   Jackson County, Chevron USA Inc Ser 1993....................          3.55    07/01/96           7,000,000
    5,500   Mississippi Business Finance Corporation, Mississippi Power
              Co (AMT)..................................................          3.75    07/01/96           5,500,000
            MISSOURI
   20,000   Missouri Health & Educational Facilities Authority, Sisters
              of Mercy Health System St Louis Inc Ser 1989 A............          3.35    07/01/96          20,000,000
            NEBRASKA
            Nebraska Higher Education Loan Program Inc,
   10,000     1985 Ser E (MBIA).........................................          3.40    07/08/96          10,000,000
    8,600     1986 Ser C (AMT)..........................................          3.50    07/08/96           8,600,000
            NEW HAMPSHIRE
    2,500   New Hampshire Higher Educational & Health Facilities
              Authority, Dartmouth Education Loan Corp Ser 1993 (AMT)...          3.90    06/01/97           2,500,000
</TABLE>
    
 
   
                                       12
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            NEW JERSEY
$  11,000   New Jersey Economic Development Authority, New Jersey
              Natural Gas Co Ser 1995 A (AMBAC).........................          3.50%   07/01/96     $    11,000,000
    8,000   New Jersey Turnpike Authority, Ser 1991 D (FGIC)............          3.00    07/08/96           8,000,000
    6,400   Union County Industrial Pollution Control Financing
              Authority, Exxon Corp Ser 1994............................          2.90    07/01/96           6,400,000
            NEW MEXICO
   39,200   Albuquerque, Airport Sub Lien Ser 1995 (AMBAC)..............          3.30    07/08/96          39,200,000
            NEW YORK
   14,800   New York Local Government Assistance Corporation, Ser 1995
              B.........................................................          3.10    07/08/96          14,800,000
    1,000   St Lawrence County Industrial Development Agency, Reynolds
              Metals Co Ser 1995 (AMT)..................................          3.35    07/08/96           1,000,000
            NORTH CAROLINA
    9,400   Craven County Industrial Facilities & Pollution Control
              Financing Authority, Craven County Wood Energy Ltd 1989
              Ser C (AMT)...............................................          3.75    07/01/96           9,400,000
    9,800   Durham, Ser 1993 A COPs.....................................          3.20    07/08/96           9,800,000
   26,985   North Carolina Medical Care Commission, Duke University
              Hospital Ser 1985 B & C...................................          3.25    07/08/96          26,985,000
   21,700   Person County Industrial Facilities & Pollution Control
              Financing Authority, Carolina Power & Light Co Ser 1992
              A.........................................................          3.25    07/08/96          21,700,000
            OHIO
    1,300   Dayton, Emery Air Freight Co 1988 Ser C.....................          3.70    07/01/96           1,300,000
    5,600   Ohio Air Quality Development Authority, Cincinnati Gas &
              Electric Co Ser A.........................................          3.50    07/01/96           5,600,000
   12,000   Ohio Housing Financing Agency, Residential Mtg 1996 Ser A-3
              (AMT).....................................................          3.40    03/03/97          12,000,000
            OKLAHOMA
            Oklahoma Water Resources Board,
   18,750     State Loan Prog Ser 1994 A................................          3.25    09/01/96          18,750,000
   10,000     State Loan Prog Ser 1995..................................          3.10    09/03/96          10,000,000
            PENNSYLVANIA
   10,000   Allegheny County Hospital Development Authority, Health
              Education & Research Corp Ser 1988 B......................          3.30    07/08/96          10,000,000
   10,000   Beaver County Industrial Development Authority, Toledo
              Edison Co 1992 Ser E......................................          3.65    07/05/96          10,000,000
    6,800   Delaware County Industrial Development Authority, United
              Parcel Service of America Inc Ser 1995....................          3.60    07/01/96           6,800,000
   10,500   Pennsylvania Energy Development Authority, Clarion Co Piney
              Creek Ser A (AMT).........................................          3.55    07/08/96          10,500,000
            Pennsylvania Higher Education Facilities Authority,
    7,000     Temple University Ser 1984-1..............................          3.60    07/08/96           7,000,000
    5,000     Thomas Jefferson University Ser 1992 C....................          3.25    08/26/96           5,000,000
   10,000   Philadelphia Hospitals & Higher Educational Facilities
              Authority, Children's Hospital of Philadelphia 1996 Ser
              A.........................................................          3.60    07/01/96          10,000,000
    8,300   Washington County Authority, Pooled Ser 1985 A-1 Subser B...          3.25    07/08/96           8,300,000
            SOUTH CAROLINA
    5,905   York County, Saluda River Electric Coop Inc Ser 1984 E-2
              (NRU-CFC Gtd).............................................          3.10    08/15/96           5,905,000
            TENNESSEE
    7,704   Clarksville Public Building Authority Ser 1990 (MBIA).......          3.30    07/08/96           7,704,000
    7,900   Memphis, Airport Refg Ser 1995 B............................          3.50    07/08/96           7,900,000
   20,000   Volunteer State Student Funding, Ser A-3 (AMT)..............          3.60    07/08/96          20,000,000
</TABLE>
    
 
   
                                       13
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            TEXAS
$   8,400   Gulf Coast Waste Disposal Authority, Amoco Oil Co Ser
              1992......................................................          3.50%   07/01/96     $     8,400,000
   28,000   Harris County, Toll Road Unlimited Tax Sub Lien Ser 1994 B &
              C.........................................................          3.40    07/08/96          28,000,000
   10,000   Hockley County Industrial Development Corporation, Amoco Oil
              Co Ser 1985...............................................          3.60    11/01/96          10,000,000
    6,500   Sabine River Authority, Texas Utilities Co Ser 1996 A
              (AMBAC)...................................................          3.60    07/01/96           6,500,000
   15,000   Texas, Veterans' Housing Assistance Fund I Ser 1995.........          3.30    07/08/96          15,000,000
            UTAH
   25,000   Intermountain Power Agency, 1985 Ser E......................          3.35    09/15/96          25,000,000
            VIRGINIA
   15,000   Virginia Housing Development Authority, 1995 Subser D STEM
              IV........................................................          3.35    07/16/96          15,000,000
            WASHINGTON
    5,800   Seattle, Municipal Light & Power Ser 1993...................          3.40    07/08/96           5,800,000
            WISCONSIN
    9,500   Brokaw, Wausau Paper Mills Co Ser 1995 (AMT)................          3.60    07/08/96           9,500,000
   10,000   Wisconsin Health Facilities Authority, Franciscan Health
              Care Inc Ser 1985 A-1.....................................          3.45    07/08/96          10,000,000
            WYOMING
   10,200   Lincoln County, Exxon Corp Ser 1987 A (AMT).................          3.70    07/01/96          10,200,000
    8,250   Sublette County, Exxon Corp Ser 1987 A (AMT)................          3.65    07/01/96           8,250,000
    4,100   Sweetwater County, PacifiCorp Ser 1994 (AMBAC)..............          3.70    07/01/96           4,100,000
                                                                                                       ---------------
            TOTAL SHORT-TERM VARIABLE RATE MUNICIPAL OBLIGATIONS
              (AMORTIZED COST $1,193,445,957)....................................................        1,193,445,957
                                                                                                       ---------------
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
                                                                                                      ON DATE
                                                                             COUPON     MATURITY        OF
                                                                              RATE        DATE        PURCHASE
                                                                          ------------  ---------     -------
<C>         <S>                                                           <C>           <C>           <C>          <C>
            TAX-EXEMPT COMMERCIAL PAPER (19.7%)
            FLORIDA
    7,000   Florida Local Government Finance Commission, Ser 1991.......        3.60%   08/28/96           3.60%         7,000,000
    8,690   Jacksonville, Florida Power & Light Co Ser 1994.............        3.60    11/15/96           3.60          8,690,000
   10,700   Jacksonville Electric Authority, Ser A......................        3.65    10/24/96           3.65         10,700,000
            Palm Beach County Health Facilities Authority,
    6,500     Pooled Hospital Ser 1985 (MBIA)...........................        3.55    07/11/96           3.55          6,500,000
    5,500     Pooled Hospital Ser 1985 (MBIA)...........................        3.60    07/25/96           3.60          5,500,000
   12,425   Sunshine State Governmental Financing Commission, Ser 1994
              B.........................................................        3.30    07/30/96           3.30         12,425,000
            GEORGIA
   10,400   Burke County Development Authority, Oglethorpe Power Corp
              Ser 1992 A................................................        3.55    11/07/96           3.55         10,400,000
    8,000   Georgia Municipal Gas Authority, Transco Portfolio 1 Ser
              A.........................................................        3.35    08/27/96           3.35          8,000,000
            HAWAII
    4,000   Hawaii Department of Budget & Finance, Citizens Utilities Co
              1988 Ser B (AMT)..........................................        3.70    08/20/96           3.70          4,000,000
            INDIANA
   10,000   Indianapolis, Citizens Gas & Coke Utility...................        3.55    09/09/96           3.55         10,000,000
            MARYLAND
   12,000   Baltimore County, Ser 1995 BANs.............................        3.45    09/11/96           3.45         12,000,000
</TABLE>
    
 
                                       14
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
PRINCIPAL                                                                                             ON DATE
AMOUNT (IN                                                                   COUPON     MATURITY        OF
THOUSANDS)                                                                    RATE        DATE        PURCHASE          VALUE
- ----------                                                                ------------  ---------     -------      ---------------
            MASSACHUSETTS
<C>         <S>                                                           <C>           <C>           <C>          <C>
$  10,000   Massachusetts Health & Educational Facilities Authority,
              Boston University Ser H...................................        3.65%   08/22/96           3.65%   $    10,000,000
            Massachusetts Water Resources Authority,
   10,000     Ser 1994..................................................        3.30    07/31/96           3.30         10,000,000
   10,000     Ser 1994..................................................        3.30    08/14/96           3.30         10,000,000
            MINNESOTA
   10,000   Southern Minnesota Municipal Power Agency, Ser B............        3.60    10/17/96           3.60         10,000,000
            MISSOURI
   15,145   Missouri Environmental Improvement & Energy Resources
              Authority, Union Electric Co Ser 1985 A...................        3.50    07/15/96           3.50         15,145,000
            NEBRASKA
   15,000   Nebraska Public Power District, Ser B Notes.................        3.65    09/12/96           3.65         15,000,000
            NEW HAMPSHIRE
   10,000   New Hampshire Business Finance Authority, New England Power
              Co 1990 Ser A (AMT).......................................        3.80    08/08/96           3.80         10,000,000
            NORTH CAROLINA
            North Carolina Municipal Power Agency Number 1,
   11,510     Catawba Ser A.............................................        3.60    10/11/96           3.60         11,510,000
   10,000     Catawba Ser A.............................................        3.60    11/12/96           3.60         10,000,000
            SOUTH CAROLINA
            South Carolina Public Service Authority,
   10,000     Promissory Notes..........................................        3.60    10/10/96           3.60         10,000,000
   10,542     Promissory Notes..........................................        3.60    10/22/96           3.60         10,542,000
   10,000     Promissory Notes..........................................        3.60    10/29/96           3.60         10,000,000
            TEXAS
            Houston,
   16,000     1993 Ser A................................................        3.43    07/10/96           3.43         16,000,000
    4,000     1993 Ser A................................................        3.50    10/30/96           3.50          4,000,000
   10,900     1993 Ser A................................................        3.50    10/30/96           3.50         10,900,000
   10,000   Houston, Water & Sewer Ser A................................        3.50    10/23/96           3.50         10,000,000
    9,400   San Antonio, Water Ser 1995.................................        3.60    10/18/96           3.60          9,400,000
   10,000   Texas Municipal Power Agency................................        3.50    11/13/96           3.50         10,000,000
            WASHINGTON
    8,000   Seattle, Municipal Light & Power Ser 1990...................        3.65    10/15/96           3.65          8,000,000
            WYOMING
    7,500   Converse County, PacifiCorp Ser 1992........................        3.55    07/31/96           3.55          7,500,000
                                                                                                                   ---------------
            TOTAL TAX-EXEMPT COMMERCIAL PAPER
              (AMORTIZED COST $303,212,000)..................................................................          303,212,000
                                                                                                                   ---------------
 
            SHORT-TERM MUNICIPAL NOTES (9.5%)
            COLORADO
   15,000   Colorado, Ser 1996 A TRANs, dtd 07/01/96 (WI)...............        4.50    06/27/97           3.86         15,091,350
            IDAHO
   23,000   Idaho, Ser 1996 TANs, dtd 07/02/96 (WI).....................        4.50    06/30/97           3.90         23,132,020
            INDIANA
   10,000   Indiana Bond Bank Advance Funding Notes Ser 1996 A-2, dtd
              02/01/96..................................................        4.25    01/09/97           3.50         10,038,517
</TABLE>
    
 
   
                                       15
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
PRINCIPAL                                                                                             ON DATE
AMOUNT (IN                                                                   COUPON     MATURITY        OF
THOUSANDS)                                                                    RATE        DATE        PURCHASE          VALUE
- ----------                                                                ------------  ---------     -------      ---------------
            IOWA
<C>         <S>                                                           <C>           <C>           <C>          <C>
$  30,000   Iowa School Corporations, Warrant Certificates Ser 1996-97
              (FSA), dtd 06/27/96.......................................        4.75%   06/27/97           3.95%   $    30,229,436
            MASSACHUSETTS
   15,000   Massachusetts, 1996 Ser A Notes, dtd 06/11/96...............        4.25    06/10/97           3.90         15,047,754
            MICHIGAN
            Michigan Municipal Bond Authority,
   23,000     Ser 1995 B Notes, dtd 07/03/95............................        4.50    07/03/96           3.80         23,001,694
   20,000     Ser 1996 A Notes, dtd 07/03/96 (WI).......................        4.50    07/03/97           3.90         20,115,400
   10,000   Michigan, Notes dtd 02/20/96................................        4.00    09/30/96           3.00         10,025,022
                                                                                                                   ---------------
            TOTAL SHORT-TERM MUNICIPAL NOTES
              (AMORTIZED COST $146,681,193)..................................................................          146,681,193
                                                                                                                   ---------------
</TABLE>
    
 
   
<TABLE>
<C>          <S>                                                                 <C>    <C>
             TOTAL INVESTMENTS (AMORTIZED COST $1,643,339,150) (A).......        106.6%  1,643,339,150
             LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS..............        (6.6 )   (101,452,021)
                                                                                 -----  --------------
             NET ASSETS..................................................        100.0% $1,541,887,129
                                                                                 -----  --------------
                                                                                 -----  --------------
</TABLE>
    
 
- ------------
 
   
      AMT        ALTERNATIVE MINIMUM TAX.
     BANs        Bond Anticipation Notes.
     COPs        Certificates of Participation.
     TANs        Tax Anticipation Notes.
     TRANs       Tax and Revenue Anticipation Notes.
      WI         Security purchased on a when issued basis.
       +         Rate shown is the rate in effect at June 30, 1996.
       *         Date in which the principal amount can be
                 recovered through demand.
      (a)        Cost is the same for federal income tax purposes.
Bond Insurance:
     AMBAC       AMBAC Indemnity Corporation.
     CGIC        Capital Guaranty Insurance Company.
     FGIC        Financial Guaranty Insurance Company.
      FSA        Financial Security Assurance Inc.
     MBIA        Municipal Bond Investors Assurance Corporation.
 
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       16
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
To the Shareholders and Trustees of Active Assets Tax-Free Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material respects, the  financial position of  Active Assets Tax-Free Trust
(the "Trust") at June 30, 1996, the results of its operations for the year  then
ended,  the changes in  its net assets for  each of the two  years in the period
then ended and the financial highlights for each of the ten years in the  period
then  ended, in conformity with  generally accepted accounting principles. These
financial  statements  and  financial  highlights  (hereafter  referred  to   as
"financial  statements") are the  responsibility of the  Trust's management; our
responsibility is to express an opinion  on these financial statements based  on
our  audits. We conducted our audits of these financial statements in accordance
with generally  accepted  auditing standards  which  require that  we  plan  and
perform  the audit  to obtain reasonable  assurance about  whether the financial
statements are free of material misstatement. An audit includes examining, on  a
test  basis, evidence  supporting the amounts  and disclosures  in the financial
statements, assessing the accounting  principles used and significant  estimates
made by management, and evaluating the overall financial statement presentation.
We  believe that our  audits, which included confirmation  of securities at June
30, 1996 by correspondence with the custodian and brokers, provide a  reasonable
basis for the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
   
                      1996 FEDERAL TAX NOTICE (UNAUDITED)
During  the year ended June 30, 1996,  the Trust paid to shareholders $0.031 per
share from  net  investment  income.  All of  the  Trust's  dividends  from  net
investment  income were exempt interest  dividends, excludable from gross income
for Federal income tax purposes.
    
 
                                       17
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
 
       TWO WORLD TRADE CENTER, NEW YORK, NEW YORK 10048 - (212) 392-5000
 
    Active  Assets California Tax-Free Trust (the "California Tax-Free Trust" or
the "Trust") is a no-load,  diversified open-end management investment  company.
The  Trust is authorized to reimburse Dean Witter Distributors Inc. for specific
expenses incurred in promoting the  distribution of the Trust's shares  pursuant
to  a Plan of Distribution  pursuant to Rule 12b-1  under the Investment Company
Act of 1940, as  amended (the "Act").  Reimbursement may in  no event exceed  an
amount  equal to payments at  the annual rate of 0.15%  of the average daily net
assets of the Trust.
 
   
    The investment objective of the Trust is to provide as high a level of daily
income exempt from federal and California  personal income tax as is  consistent
with  stability  of principal  and  liquidity. The  Trust  seeks to  achieve its
objective  by  investing  primarily  in  high  quality,  California   tax-exempt
securities with short-term maturities including Municipal Bonds, Municipal Notes
and Municipal Commercial Paper. The Trust may invest a significant percentage of
its  assets in the securities of a  single issuer and therefore an investment in
the Trust may be riskier than an investment in other types of money funds.
    
 
    AN INVESTMENT IN  THE TRUST IS  NEITHER INSURED NOR  GUARANTEED BY THE  U.S.
GOVERNMENT.  THERE IS  NO ASSURANCE THAT  THE TRUST  WILL BE ABLE  TO MAINTAIN A
STABLE NET ASSET VALUE OF $1.00 PER SHARE.
 
    SHARES OF THE  TRUST ARE NOT  DEPOSITS OR OBLIGATIONS  OF, OR GUARANTEED  OR
ENDORSED  BY, ANY BANK, AND THE SHARES  ARE NOT FEDERALLY INSURED BY THE FEDERAL
DEPOSIT INSURANCE CORPORATION, THE FEDERAL RESERVE BOARD, OR ANY OTHER AGENCY.
                               TABLE OF CONTENTS
 
   
<TABLE>
<S>                                                 <C>
Highlights/2                                        How Net Asset Value is Determined/A-4
Summary of Trust Expenses/3                         Confirmations/A-5
Financial Highlights/3                              The Trusts and Their Management/A-5
Investment Objective and Policies/4                 Plan of Distribution/A-6
Investment Restrictions/8                           Dividends, Distributions and Taxes/A-6
Financial Statements -- June 30, 1996/9             General Information/A-9
Report of Independent Accountants/16                Voting Rights/A-9
Purchase and Redemption of Shares/A-1               Custodian/A-10
    Purchase of Shares/A-1                          Shareholder Inquiries/A-10
    Purchase of Shares by Non-Participants in
     the Active Assets Program/A-2
    Redemption of Shares/A-3
    Redemption of Shares by Non-Participants in
    the Active Assets Program/A-4
</TABLE>
    
 
   
    THIS PROSPECTUS SETS FORTH CONCISELY THE INFORMATION YOU SHOULD KNOW  BEFORE
INVESTING  IN THE TRUST.  IT SHOULD BE  READ AND RETAINED  FOR FUTURE REFERENCE.
ADDITIONAL INFORMATION  ABOUT  THE  TRUST  IS  CONTAINED  IN  THE  STATEMENT  OF
ADDITIONAL  INFORMATION, DATED  AUGUST 22, 1996,  WHICH HAS BEEN  FILED WITH THE
SECURITIES AND EXCHANGE  COMMISSION, AND WHICH  IS AVAILABLE AT  NO CHARGE  UPON
REQUEST  OF THE TRUST AT THE ADDRESS LISTED  ABOVE OR BY CALLING THE DEAN WITTER
INTERCAPITAL  INC.  (THE  "INVESTMENT  MANAGER"  OR  "INTERCAPITAL")  AT   (212)
392-2550.  THE  STATEMENT OF  ADDITIONAL INFORMATION  IS INCORPORATED  HEREIN BY
REFERENCE.
    
 
    THE INFORMATION IN THIS  PROSPECTUS SHOULD BE READ  IN CONJUNCTION WITH  THE
INFORMATION APPEARING ELSEWHERE IN THIS DOCUMENT, INCLUDING THE APPENDIX HERETO,
WHICH IS PART OF THIS PROSPECTUS, AND IN THE DEAN WITTER CLIENT AGREEMENT.
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
    EXCHANGE  COMMISSION OR ANY  STATE SECURITIES COMMISSION  NOR HAS THE
       SECURITIES AND EXCHANGE  COMMISSION OR  ANY STATE  SECURITIES
            COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
                 PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY
                                  IS A CRIMINAL OFFENSE.
 
                            ------------------------
 
   
                THE DATE OF THIS PROSPECTUS IS AUGUST 22, 1996.
    
 
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
HIGHLIGHTS
 
   
<TABLE>
<S>                    <C>
THE                    A  no-load, open-end diversified management investment  company investing principally in short-term
TRUST                  securities exempt from  federal and  California personal  income tax.  The Trust  is authorized  to
                       reimburse   Dean  Witter  Distributors  Inc.  for  specific  expenses  incurred  in  promoting  the
                       distribution of the Trust's shares pursuant to a Plan of Distribution pursuant to Rule 12b-1  under
                       the  Act (See page A-6). The Trust is organized  as an unincorporated business trust under the laws
                       of Massachusetts. (See page A-5).
- ------------------------------------------------------------------------------------------------------------------------
SHARES                 The shares of the Trust are offered to participants in the Active Assets program of Dean Witter and
OFFERED                to non- participants  who wish  to invest  directly in shares  of the  Trust. (See  page A-2).  The
                       primary  components of the Active Assets program are the Securities Account, which is linked to the
                       Active Assets Insured Account, the Active Assets Money Trust, the Active Assets Tax-Free Trust, the
                       California Tax-Free Trust or the Active Assets Government Securities Trust and to the Visa Account.
                       See the Dean Witter Client Agreement for further information.
- ------------------------------------------------------------------------------------------------------------------------
PURCHASE               Pursuant to the Dean Witter Client Agreement between Dean Witter and the customer, free credit cash
OF SHARES              balances will be automatically  invested daily in shares  of the Trust at  their current net  asset
                       value  without any sales charge. Dean Witter Distributors  Inc. is the Distributor of shares of the
                       Trust. Investments  in  shares are  made  under the  circumstances  described under  "Purchase  and
                       Redemption of Shares" (see page A-1). Non-participants in the Active Assets program should refer to
                       the discussion appearing at page A-2.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             High  level  of daily  California  tax-exempt income  consistent  with stability  of  principal and
OBJECTIVE              liquidity (see page 4).  There can be no  assurance that the Trust's  investment objective will  be
                       achieved.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             A diversified portfolio of tax-exempt, fixed-income securities with short-term maturities (see page
POLICY                 4).
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             Dean  Witter  InterCapital  Inc.,  the  Investment  Manager  of  the  Trust,  and  its wholly-owned
MANAGER                subsidiary, Dean Witter Services Company, Inc.,  serve in various investment management,  advisory,
                       management  and administrative  capacities to ninety-eight  investment companies  with assets under
                       management of approximately $84.6 billion at June 30, 1996 (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
MANAGEMENT             Monthly fee at an annual rate of 1/2 of 1% of average daily net assets, scaled down on assets  over
FEE                    $500 million (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
DIVIDENDS              Automatically reinvested daily in additional shares at net asset value (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
DISTRIBUTOR            Dean  Witter Distributors Inc.  (the "Distributor") sells  shares of the  Trust through Dean Witter
                       Reynolds Inc.  Other  than  the  reimbursement  to the  Distributor  pursuant  to  the  Rule  12b-1
                       Distribution Plan, the Distributor receives no distribution fees (see page A-2).
- ------------------------------------------------------------------------------------------------------------------------
PLAN OF                The  Trust is authorized to  reimburse specific expenses incurred  in promoting the distribution of
DISTRIBUTION           the Trust's shares pursuant to a Plan of  Distribution with the Distributor pursuant to Rule  12b-1
                       under  the Investment Company Act of 1940. Reimbursement may  in no event exceed an amount equal to
                       payments at the annual rate of 0.15 of 1% of average daily net assets of the Trust (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
REPORTS                Individual monthly account statements  from Dean Witter on  the Dean Witter Transaction  Statement;
                       annual and semi-annual Trust financial statements.
- ------------------------------------------------------------------------------------------------------------------------
REDEMPTION             For  participants in the Active Assets  program, shares of the Trust  will be redeemed at net asset
OF SHARES              value automatically to satisfy debit balances in the Securities Account created by activity therein
                       or to satisfy amounts owing in the Visa  Account resulting from Visa card purchases, cash  advances
                       or  checks written against the  Visa Account. Non-participants in  the Active Assets program should
                       refer to the discussion  appearing at page  A-4. It is  anticipated that the  net asset value  will
                       remain  constant at $1.00 per share. Dean Witter  has the right to terminate a shareholder's Active
                       Assets service,  in  which  event  all  Trust  shares held  in  a  shareholder's  account  will  be
                       involuntarily  redeemed. The Trust  also reserves the right  to reduce the number  of shares in all
                       accounts if the Trustees determine that this is necessary to maintain the constant $1.00 per  share
                       net asset value. See "Purchase and Redemption of Shares" (page A-1).
- ------------------------------------------------------------------------------------------------------------------------
RISKS                  The  Trust  invests  principally in  high  quality,  short-term fixed-income  securities  issued or
                       guaranteed by the state of California and its  local governments which are subject to minimal  risk
                       of  loss of income  and principal. However, the  investor is directed to  the discussions of "lease
                       obligations" (page 5)  and "When-Issued and  Delayed Delivery Securities"  (page 6) concerning  the
                       risks  associated  with  such  portfolio  securities and  management  techniques.  Since  the Trust
                       concentrates its investments  in California  tax-exempt securities, the  Trust is  affected by  any
                       political,  economic or regulatory developments affecting the  ability of California issuers to pay
                       interest or repay principal (page 6).
- ------------------------------------------------------------------------------------------------------------------------
    THE SUMMARY INFORMATION ABOVE SHOULD BE READ IN CONJUNCTION WITH THE DETAILED INFORMATION APPEARING ELSEWHERE IN  THIS
PROSPECTUS,  INCLUDING THE APPENDIX HERETO, IN THE DEAN WITTER CLIENT AGREEMENT AND IN THE TRUST'S STATEMENT OF ADDITIONAL
INFORMATION, INCLUDING THE APPENDIX THERETO.
</TABLE>
    
 
                                       2
 
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
SUMMARY OF TRUST EXPENSES
- --------------------------------------------------------------------------------
 
    The  following table illustrates all expenses and fees that a shareholder of
the Trust will incur. The expenses and fees  set forth in the table are for  the
fiscal year ended June 30, 1996.
 
<TABLE>
<S>                                       <C>
SHAREHOLDER TRANSACTION EXPENSES
Maximum Sales Charge Imposed on
 Purchases..............................    None
Maximum Sales Charge Imposed on
 Reinvested Dividends...................  None
Deferred Sales Charge...................  None
Redemption Fees.........................  None
Exchange Fee............................  None
ANNUAL TRUST OPERATING EXPENSES (AS A
 PERCENTAGE OF AVERAGE NET ASSETS)
Management Fees.........................    0.50%
12b-1 Fees..............................    0.10%
Other Expenses..........................    0.07%
                                          -------
Total Trust Operating Expenses..........    0.67%
                                          -------
                                          -------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                          10
EXAMPLE                                   1 YEAR    3 YEARS   5 YEARS    YEARS
- ----------------------------------------  -------   -------   -------   -------
<S>                                       <C>       <C>       <C>       <C>
You would pay the following expenses on
  a $1,000 investment, assuming (1) 5%
  annual return and (2) redemption at
  the end of each time period:              $ 7       $21       $37       $83
</TABLE>
 
    Dean Witter charges an annual Active Assets program participation fee of $80
($100 for corporate participants). Shareholders of the Trust who are not program
participants will not be charged an Active Assets program fee.
 
    The  above  example should  not be  considered a  representation of  past or
future expenses or performance. Actual expenses  of the Trust may be greater  or
less than those shown.
 
    The  purpose of this  table is to  assist the investor  in understanding the
various costs and expenses that an investor  in the Trust will bear directly  or
indirectly.  For a  more complete description  of these costs  and expenses, see
pages A-5 and A-6 in the Appendix to this Prospectus.
 
FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------
 
   
    The following ratios and per share  data for a share of beneficial  interest
outstanding  throughout each period  have been audited  by Price Waterhouse LLP,
independent accountants. The financial highlights should be read in  conjunction
with  the financial statements  and notes thereto and  the unqualified report of
independent accountants which  are contained  in this  Prospectus commencing  on
page 9.
    
 
   
<TABLE>
<CAPTION>
                                                                                                  FOR THE PERIOD
                                                     FOR THE YEAR ENDED JUNE 30,                NOVEMBER 12, 1991*
                                          -------------------------------------------------          THROUGH
                                             1996         1995         1994         1993          JUNE 30, 1992
                                          ----------   ----------   ----------   ----------   ----------------------
<S>                                       <C>          <C>          <C>          <C>          <C>
PER SHARE OPERATING PERFORMANCE:
Net asset value, beginning of period....  $   1.00     $   1.00     $   1.00     $   1.00            $  1.00
                                          ----------   ----------   ----------   ----------          -------
Net investment income...................     0.028        0.029        0.018        0.018              0.017
Less dividends from net investment
 income.................................    (0.028)      (0.029)      (0.018)      (0.018)            (0.017)
                                          ----------   ----------   ----------   ----------          -------
Net asset value, end of period..........  $   1.00     $   1.00     $   1.00     $   1.00            $  1.00
                                          ----------   ----------   ----------   ----------          -------
                                          ----------   ----------   ----------   ----------          -------
TOTAL INVESTMENT RETURN+................      2.82%        2.89%        1.78%        1.84%              1.66%(1)
RATIOS TO AVERAGE NET ASSETS:
  Expenses..............................      0.67%        0.67%        0.68%        0.71%              0.56%(2)(3)
  Net investment income.................      2.79%        2.86%        1.77%        1.82%              2.42%(2)(3)
SUPPLEMENTAL DATA:
Net assets, end of period, in
 thousands..............................  $384,218     $313,566     $288,506     $202,149           $170,364
</TABLE>
    
 
- -----------------
 
   
<TABLE>
<C>        <S>
    *      COMMENCEMENT OF OPERATIONS.
    +      CALCULATED BASED ON THE NET ASSET VALUE AS OF THE LAST BUSINESS DAY OF THE PERIOD.
   (1)     NOT ANNUALIZED.
   (2)     ANNUALIZED.
   (3)     IF  THE TRUST HAD BORNE ALL EXPENSES THAT WERE ASSUMED  OR WAIVED BY THE INVESTMENT MANAGER, THE ABOVE ANNUALIZED EXPENSE
           AND NET INVESTMENT INCOME RATIOS WOULD HAVE BEEN 0.80% AND 2.18%, RESPECTIVELY.
</TABLE>
    
 
                                       3
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
INVESTMENT OBJECTIVE AND POLICIES
- --------------------------------------------------------------------------------
 
    THE INVESTMENT OBJECTIVE OF THE TRUST IS TO PROVIDE AS HIGH A LEVEL OF DAILY
INCOME  EXEMPT FROM FEDERAL AND CALIFORNIA  PERSONAL INCOME TAX AS IS CONSISTENT
WITH STABILITY OF  PRINCIPAL AND LIQUIDITY.  It is a  fundamental policy of  the
Trust  that at least 80% of its total  assets will be invested in securities the
interest on which  is exempt  from federal  and California  personal income  tax
("California  tax-exempt securities").  This policy  and the  Trust's investment
objective may  not be  changed  without a  vote of  a  majority of  the  Trust's
outstanding voting securities, as defined in the Act. There is no assurance that
the objective will be achieved.
 
    The  Trust seeks to achieve its  investment objective by investing primarily
in  high  quality  tax-exempt   securities  with  short-term  maturities.   Such
securities  will include California Municipal  Bonds, California Municipal Notes
and  California  Municipal  Commercial  Paper  ("Municipal  Obligations")   with
maturities of thirteen months or less, which are rated in one of the two highest
rating  categories for  debt obligations by  at least  two nationally recognized
statistical  rating  organizations  ("NRSRO's"--  primarily  Moody's   Investors
Service  ("Moody's") and Standard & Poor's Corporation ("S&P")), or one NRSRO if
the obligation is rated by only one NRSRO. Unrated obligations may be  purchased
if they are determined to be of comparable quality by the Trust's Trustees.
 
    Up  to 20% of  the Trust's total  assets may also  be invested in securities
exempt from federal personal income tax but not from California personal  income
tax  ("non-California  tax-exempt  securities"), in  taxable  securities  and in
tax-exempt securities  subject  to  the  federal  alternative  minimum  tax  for
individual shareholders ("AMT") (California tax-exempt securities subject to AMT
will  not  be included  in the  80% total  referred to  above for  investment in
California tax-exempt securities). In addition, the Trust may temporarily invest
more than  20%  of  its  total  assets  in  taxable  securities,  non-California
tax-exempt securities, or in tax-exempt securities subject to AMT, to maintain a
"defensive"  posture  when, in  the  opinion of  the  Investment Manager,  it is
advisable to do so because of market conditions. The types of taxable securities
in which  the  Trust  may  temporarily  invest  are  limited  to  the  following
short-term fixed-income securities (maturing in thirteen months or less from the
time  of  purchase); (i)  obligations  of the  United  States Government  or its
agencies, instrumentalities or authorities; (ii)  commercial paper rated P-1  by
Moody's  or A-1  by S&P;  (iii) certificates of  deposit of  domestic banks with
assets of $1 billion or more; and (iv) repurchase agreements with respect to any
of the foregoing portfolio securities.
 
    California  Municipal  Bonds  and   California  Municipal  Notes  are   debt
obligations  of a state, its cities, municipalities and municipal agencies which
generally have maturities, at the time of their issuance, of either one year  or
more  (Bonds) or  from six months  to three years  (Notes). California Municipal
Commercial  Paper  refers  to  short-term  obligations  of  municipalities.  Any
Municipal  Obligation which depends on the credit of the Federal Government, its
agencies or instrumentalities shall  be considered to have  a Moody's rating  of
Aaa  or  S&P  rating of  AAA.  An  obligation shall  be  considered  a Municipal
Obligation only  if,  in the  opinion  of  bond counsel,  the  interest  payable
therefrom  is exempt from both federal income tax and California personal income
tax.
 
    The foregoing  percentage  and  rating  limitations apply  at  the  time  of
acquisition  of  a security  based  on the  last  previous determination  of the
Trust's net asset value. Any subsequent change in any rating by a rating service
or change  in percentages  resulting from  market fluctuations  may not  require
elimination  of any security from the  Trust's portfolio. However, in accordance
with procedures adopted by the  Trust's Trustees pursuant to federal  securities
regulations  governing money market funds, the Investment Manager will perform a
 
                                       4
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
creditworthiness analysis of such downgraded securities, which analysis will  be
reported  to the  Trustees who will,  in turn, determine  whether the securities
continue to  present minimal  credit risks  to  the Trust.  The Trust  does  not
anticipate that more than 5% of its net assets are likely to be downgraded below
the rating requirements described above for Municipal Obligations.
 
    The ratings assigned by NRSROs represent their opinions as to the quality of
the  securities which they undertake to rate  (see the Appendix to the Statement
of Additional Information  for an explanation  of Moody's and  S&P ratings).  It
should  be emphasized,  however, that the  ratings are general  and not absolute
standards of quality.
 
    The two  principal classifications  of  Municipal Obligations  are  "general
obligation"  and "revenue" bonds, notes  or commercial paper. General obligation
bonds, notes  or commercial  paper are  secured by  the issuer's  pledge of  its
faith,  credit  and taxing  power  for the  payment  of principal  and interest.
Issuers of general obligation bonds, notes or commercial paper include a  state,
its  counties, cities, towns and other  governmental units. Revenue bonds, notes
or commercial paper  are payable  from the  revenues derived  from a  particular
facility  or  class  of facilities  or,  in  some cases,  from  specific revenue
sources. Revenue bonds, notes or commercial paper are issued for a wide  variety
of  purposes, including the financing of  electric, gas, water and sewer systems
and  other  public  utilities;  industrial  development  and  pollution  control
facilities;   single  and  multi-family  housing  units;  public  buildings  and
facilities; air and marine ports, transportation facilities such as toll  roads,
bridges and tunnels; and health and educational facilities such as hospitals and
dormitories.  They rely primarily on user fees to pay debt service, although the
principal revenue source is often  supplemented by additional security  features
which  are intended to enhance the creditworthiness of the issuer's obligations.
In some cases, particularly revenue bonds  issued to finance housing and  public
buildings,  a direct or implied "moral obligation" of a governmental unit may be
pledged to the payment of debt service.  In other cases, a special tax or  other
charge may augment user fees.
 
    Included  within  the revenue  bonds  category are  participations  in lease
obligations or installment purchase  contracts (hereinafter collectively  called
"lease  obligations") of municipalities. State and local agencies or authorities
issue lease obligations to acquire equipment and facilities.
 
    Lease obligations  may  have  risks not  normally  associated  with  general
obligation   or  other  revenue  bonds.  Leases,  and  installment  purchase  or
conditional sale contracts (which may provide  for title to the leased asset  to
pass  eventually  to the  issuer), have  developed as  a means  for governmental
issuers to acquire  property and  equipment without the  necessity of  complying
with  the constitutional and statutory requirements generally applicable for the
issuance of debt. Certain lease obligations contain "non-appropriation"  clauses
that  provide  that the  governmental issuer  has no  obligation to  make future
payments under  the lease  or contract  unless money  is appropriated  for  such
purpose  by  the appropriate  legislative body  on an  annual or  other periodic
basis.  Consequently,  continued  lease  payments  on  those  lease  obligations
containing  "non-appropriation"  clauses  are  dependent  on  future legislative
actions. If such  legislative actions  do not occur,  the holders  of the  lease
obligation  may  experience  difficulty in  exercising  their  rights, including
disposition of the property.
 
   
    Certain lease  obligations have  not developed  the depth  of  marketability
associated  with more conventional municipal obligations,  and, as a result, may
be considered illiquid securities.  To determine whether or  not the Trust  will
consider  such securities to be illiquid (the Trust may not invest more than ten
percent of its  net assets in  illiquid securities), the  Trustees of the  Trust
have  established  guidelines to  be utilized  by the  Trust in  determining the
liquidity of a  lease obligation.  The factors to  be considered  in making  the
determination  include: 1)  the frequency  of trades  and quoted  prices for the
obligation; 2) the number  of dealers willing to  purchase or sell the  security
and the
    
 
                                       5
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
number of other potential purchasers; 3) the willingness of dealers to undertake
to  make a market in the security; and  4) the nature of the marketplace trades,
including, the time needed to dispose of the security, the method of  soliciting
offers,  and the mechanics  of the transfer. All  lease obligations purchased by
the Trust  are subject  to the  creditworthiness standards  discussed above  for
Municipal Obligations.
 
    The  Trust does not  generally intend to  invest more than  25% of its total
assets in securities  of any one  governmental unit. The  Trust may invest  more
than  25% of  its total assets  in industrial development  and pollution control
bonds (two kinds  of tax-exempt  Municipal Bonds) whether  or not  the users  of
facilities  financed by such bonds are in the same industry. In cases where such
users are in the same  industry, there will be additional  risk to the Trust  in
the  event of an economic downturn in  such industry, which may result generally
in a lowered need for such facilities and a lowered ability of such users to pay
for the use of such facilities.
 
PORTFOLIO MANAGEMENT
 
    Although the Trust will generally acquire securities for investment with the
intent of holding them to maturity and will not seek profits through  short-term
trading,  the Trust may  dispose of any  security prior to  its maturity to meet
redemption requests. Securities  may also  be sold when  the Trust's  Investment
Manager  believes such  disposition to  be advisable on  the basis  of a revised
evaluation of the issuer or based upon relevant market considerations. There may
be occasions when, as a result of maturities of portfolio securities or sale  of
Trust shares, or in order to meet anticipated redemption requests, the Trust may
hold cash which is not earning income.
 
    The  Trust anticipates that  the average weighted  maturity of the portfolio
will be  90  days or  less.  The relatively  short-term  nature of  the  Trust's
portfolio  is expected to result  in a lower yield  than portfolios comprised of
longer-term tax-exempt securities.
 
    VARIABLE RATE AND FLOATING RATE  OBLIGATIONS. The interest rates payable  on
certain  Municipal Bonds  and Municipal  Notes are  not fixed  and may fluctuate
based upon  changes in  market rates.  Municipal obligations  of this  type  are
called "variable rate" or "floating rate" obligations. The interest rate payable
on  a variable rate  obligation is adjusted  at predesignated periodic intervals
and on a floating rate obligation, whenever there is a change in the market rate
of interest on which the interest rate payable is based.
 
    WHEN-ISSUED  AND  DELAYED  DELIVERY  SECURITIES.  The  Trust  may   purchase
tax-exempt securities on a when-issued or delayed delivery basis; i.e., delivery
and  payment can take place  a month or more after  the date of the transaction.
These securities are subject  to market fluctuation and  no interest accrues  to
the purchaser prior to settlement. At the time the Trust makes the commitment to
purchase  such securities, it will record the transaction and thereafter reflect
the value, each day, of such securities in determining its net asset value.
 
    BROKERAGE ALLOCATION.   Brokerage commissions  are not  normally charged  on
purchases  and sales of short-term  municipal obligations, but such transactions
may involve  transaction costs  in the  form of  spreads between  bid and  asked
prices.  Pursuant to  an order  of the  Securities and  Exchange Commission, the
Trust may effect principal transactions in certain money market instruments with
Dean  Witter.  In  addition,  the  Trust  may  incur  brokerage  commissions  on
transactions conducted through Dean Witter.
 
SPECIAL CONSIDERATIONS RELATING TO CALIFORNIA TAX-EXEMPT SECURITIES
 
   
    Because the Trust's investments are concentrated in securities issued by the
State of California or entities within the State, an investment in the Trust may
be  riskier  than an  investment  in other  types of  money  funds which  do not
similarly concentrate  their investments.  The  Trust will  be affected  by  any
political,   economic  or  regulatory  developments  affecting  the  ability  of
California   issuers   to   pay   interest   or   repay   principal   on   their
    
 
                                       6
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
obligations.   Various   subsequent   developments   regarding   the  California
Constitution and State of California  ("State") statutes which limit the  taxing
and  spending  authority  of  California governmental  entities  may  impair the
ability of California issuers to maintain debt service on their obligations.  Of
particular impact are constitutional voter initiatives, which have become common
in  recent years. The following information constitutes only a brief summary and
is not intended as a complete description.
 
   
    California is the most populous state in the nation with a total  population
at  the 1990 census of 29,976,000. Growth has been incessant since World War II,
with population gains in each decade since  1950 of between 18% and 49%.  During
the  last decade, the population rose 20%.  The State now comprises 12.3% of the
nation's population and 12.9% of its total personal income. Its economy is broad
and diversified  with  major  concentrations in  high  technology  research  and
manufacturing,  aerospace and defense-related manufacturing, trade, real estate,
and financial services. After experiencing strong growth throughout much of  the
1980s,  the State was adversely affected by  both the national recession and the
cutbacks in aerospace  and defense  spending which had  a severe  impact on  the
economy in Southern California. California is still experiencing some effects of
the  recession. Unemployment has remained above the national average since 1990.
Substantial contraction in California's defense related industries, overbuilding
in commercial real estate and consolidation and decline in the State's financial
services industry will likely produce  slower overall growth for several  years.
Economists  predict that  the State's economy  will experience  modest growth in
1996.
    
 
   
    These economic difficulties have exacerbated the structural budget imbalance
which has been  evident since  fiscal year  1985-1986. Since  that time,  budget
shortfalls  have become increasingly  more difficult to solve  and the State has
recorded General Fund operating deficits in several fiscal years. Many of  these
problems have been attributable to the fact that the great population influx has
produced  increased demand  for education and  social services at  a far greater
pace than  the growth  in  the State's  tax  revenues. Despite  substantial  tax
increases,   expenditure   reductions  and   the   shift  of   some  expenditure
responsibilities to local government, the budget condition remains problematic.
    
 
   
    On August 3, 1995, the Governor signed  into law a new $57.5 billion  budget
which,  among  other things,  reduces welfare  payments and  increases education
spending from the  previous fiscal  year. The  fiscal 1995-96  budget calls  for
$44.1  billion in revenues  and $43.4 billion  in spending, an  increase of over
3.5% and  4.0%,  respectively, from  the  fiscal 1994-95  budget.  Although  the
State's  budget projects an operating surplus  of approximately $600 million, it
continues to rely on federal actions, both to fund programs relating to  MediCal
and  incarceration costs associated  with illegal immigrants  and to relieve the
State from  federally mandated  spending, which  are not  certain of  occurring.
Accordingly,  the surplus  may not  be realized  unless the  economy outperforms
expectations or spending falls below planned levels.
    
 
    Because of  the  State's continuing  budget  problems, the  State's  General
Obligation  bonds were downgraded  in July 1994 from  Aa to A1  by Moody's, to A
from A+ by Standard & Poor's, and from AA to A by Fitch Investors Service,  Inc.
All  three  rating  agencies expressed  uncertainty  in the  State's  ability to
balance its budget by 1996.
 
    The effect  of these  various constitutional  and statutory  amendments  and
budget  developments upon the ability of  California issuers to pay interest and
principal on their obligations remains unclear and in any event may depend  upon
whether  a particular  California tax-exempt  security is  a general  or limited
obligation bond  and on  the  type of  security provided  for  the bond.  It  is
possible that other
 
                                       7
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
measures  affecting  the  taxing  or spending  authority  of  California  or its
political subdivisions may be approved or enacted in the future.
 
    For a more detailed discussion of the State of California economic  factors,
see the Statement of Additional Information.
 
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    Investment  restrictions listed below are  among the restrictions which have
been adopted by the Trust as fundamental policies. Under the Act, a  fundamental
policy  may not  be changed without  the vote  of a majority  of the outstanding
voting securities of the Trust, as defined in the Act.
 
   
    For purposes of the following restrictions: (a) an "issuer" of a security is
the entity whose assets  and revenues are committed  to the payment of  interest
and  principal on  that particular  security, provided  that the  guarantee of a
security will be considered  a separate security and,  provided further, that  a
guarantee  of a security shall not be  deemed a security issued by the guarantor
if the value of all securities issued  or guaranteed by the guarantor and  owned
by  the Fund does not exceed  10% of the value of  the total assets of the Fund;
(b) a "taxable security"  is any security  the interest on  which is subject  to
federal income tax; and (c) all percentage limitations apply immediately after a
purchase  or initial  investment, and  any subsequent  change in  any applicable
percentage resulting from  market fluctuations does  not require elimination  of
any security from the portfolio.
    
 
    The Trust may not:
 
        1.   With respect to 75% of its total assets, purchase securities of any
    issuer if, immediately thereafter, more than  5% (10% where the security  is
    the  guarantee of a  security) of the value  of its total  assets are in the
    securities of any one issuer  (other than obligations issued, or  guaranteed
    by,  the United States  Government, its agencies  or instrumentalities or by
    the State of California or its political subdivisions).
 
        2.  With respect to 75% of  its total assets, purchase more than 10%  of
    all  outstanding taxable debt securities of  any one issuer (other than debt
    securities issued, or guaranteed as to principal and interest by, the United
    States Government, its agencies or instrumentalities).
 
        3.  Invest  25% or  more of  the value of  its total  assets in  taxable
    securities  of  issuers  in  any one  industry  (industrial  development and
    pollution control bonds are grouped into industries based upon the  business
    in which the issuers of such obligations are engaged). This restriction does
    not  apply  to  obligations  issued  or  guaranteed  by  the  United  States
    Government, its agencies or instrumentalities or by the State of  California
    or  its political subdivisions,  or to domestic  bank obligations (including
    domestic branches of foreign banks).
 
    The Trust will  comply with  any investment policies  necessitated by  rules
governing  the pricing of shares of money market funds (see "How Net Asset Value
is Determined" in the  Appendix), even though an  investment restriction of  the
Trust is less restrictive than the related policy.
 
                                       8
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
<TABLE>
<S>                                            <C>
ASSETS:
Investments in securities, at value
  (amortized cost $430,773,691)..............  $ 430,773,691
Cash.........................................      1,222,292
Interest receivable..........................      2,297,311
Deferred organizational expenses.............          3,486
Prepaid expenses and other assets............         11,964
                                               -------------
        TOTAL ASSETS.........................    434,308,744
                                               -------------
LIABILITIES:
Payable for:
  Investments purchased......................     49,813,510
  Investment management fee..................        147,543
  Plan of distribution fee...................         29,509
  Shares of beneficial interest
    repurchased..............................             30
Accrued expenses.............................         99,988
                                               -------------
        TOTAL LIABILITIES....................     50,090,580
                                               -------------
NET ASSETS:
Paid-in-capital..............................    384,229,943
Accumulated undistributed net investment
  income.....................................             85
Accumulated net realized loss................        (11,864)
                                               -------------
        NET ASSETS...........................  $ 384,218,164
                                               -------------
                                               -------------
NET ASSET VALUE PER SHARE, 384,229,943 shares
 outstanding (unlimited shares authorized of
 $.01 par value).............................
                                                       $1.00
                                               -------------
                                               -------------
</TABLE>
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                             <C>
NET INVESTMENT INCOME:
INTEREST INCOME...............................  $12,316,979
                                                -----------
EXPENSES
  Investment management fee...................    1,781,282
  Plan of distribution fee....................      351,571
  Transfer agent fees and expenses............       73,519
  Professional fees...........................       52,993
  Shareholder reports and notices.............       36,587
  Registration fees...........................       33,292
  Trustees' fees and expenses.................       30,508
  Custodian fees..............................       21,790
  Organizational expenses.....................        9,264
  Other.......................................        7,126
                                                -----------
      TOTAL EXPENSES BEFORE EXPENSE OFFSET....    2,397,932
      LESS: EXPENSE OFFSET....................      (21,574)
                                                -----------
      TOTAL EXPENSES AFTER EXPENSE OFFSET.....    2,376,358
                                                -----------
      NET INVESTMENT INCOME...................    9,940,621
  NET REALIZED GAIN...........................        5,093
                                                -----------
      NET INCREASE............................  $ 9,945,714
                                                -----------
                                                -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                    JUNE 30,1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income......................................................    $    9,940,621      $    8,592,974
    Net realized gain..........................................................             5,093            --
                                                                                 ------------------  ------------------
        Net increase...........................................................         9,945,714           8,592,974
 
    Dividends from net investment income.......................................        (9,940,586)         (8,593,044)
    Net increase from transactions in shares of beneficial interest............        70,646,849          25,060,313
                                                                                 ------------------  ------------------
        Total increase.........................................................        70,651,977          25,060,243
NET ASSETS:
  Beginning of period..........................................................       313,566,187         288,505,944
                                                                                 ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $85 and $50,
   respectively)...............................................................    $  384,218,164      $  313,566,187
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       9
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION AND  ACCOUNTING  POLICIES--Active Assets  California Tax-Free
Trust (the "Trust") is registered under  the Investment Company Act of 1940,  as
amended  (the "Act"), as a  diversified, open-end management investment company.
The Trust's investment  objective is  to provide a  high level  of daily  income
which is exempt from federal and California income tax consistent with stability
of  principal and liquidity. The Trust was organized as a Massachusetts business
trust on July 10, 1991 and commenced operations on November 12, 1991.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that affect  the reported  amounts and  disclosures. Actual  results
could  differ from  those estimates. The  following is a  summary of significant
accounting policies:
 
    A.  VALUATION OF INVESTMENTS--Portfolio  securities are valued at  amortized
    cost, which approximates market value.
 
    B.   ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for on
    the trade date (date the order to  buy or sell is executed). Realized  gains
    and  losses on security  transactions are determined  by the identified cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.  FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with  the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies  and to distribute all of its taxable and nontaxable income to its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
    E.  ORGANIZATIONAL EXPENSES--Dean Witter InterCapital Inc. (the  "Investment
    Manager")  paid the  organizational expenses of  the Trust in  the amount of
    approximately $46,500  which  have  been  reimbursed  for  the  full  amount
    thereof.  Such expenses  have been deferred  and are being  amortized by the
    Trust on a straight-line basis over a  period not to exceed five years  from
    the commencement of operations.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement, the Trust pays the Investment Manager a management fee, accrued daily
and payable monthly, by applying the following annual rates to the net assets of
the Trust determined as of the close of each business day: 0.50% to the  portion
of the daily net assets not exceeding $500 million; 0.425% to the portion of the
daily  net assets exceeding $500 million  but not exceeding $750 million; 0.375%
to the portion of the daily net assets exceeding $750 million but not  exceeding
$1  billion; 0.35% to the  portion of the daily  net assets exceeding $1 billion
but not exceeding $1.5 billion;  0.325% to the portion  of the daily net  assets
exceeding $1.5 billion but not exceeding $2 billion; 0.30% to the portion of the
daily  net assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% to
the portion of the daily net assets exceeding $2.5 billion but not exceeding  $3
billion; and 0.25% to the portion of the daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
                                       10
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the  Trustees  determine  to  reimburse,  as  described  below.  The   following
activities   and  services  may  be  provided   by  the  Distributor  and  other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average  daily net assets during the month. Expenses incurred by the Distributor
pursuant to the  Plan in any  fiscal year will  not be reimbursed  by the  Trust
through  payments accrued in any subsequent fiscal year. For the year ended June
30, 1996, the distribution fee was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases  and proceeds  from sales/maturities  of portfolio  securities for the
year ended June 30, 1996 aggregated $903,720,425 and $795,338,000, respectively.
 
   
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $5,800.
    
 
   
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent Trustees  of the  Trust  who will  have served  as an
independent Trustee for at least five years at the time of retirement.  Benefits
under  this plan are based on years  of service and compensation during the last
five years of service. Aggregate pension cost  for the year ended June 30,  1996
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $14,185. At  June 30, 1996,  the Trust  had an accrued  pension liability  of
$30,297  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
    
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     1,301,311,516      1,156,418,032
Shares issued in reinvestment of dividends.......................................         9,940,586          8,593,044
                                                                                   -----------------  -----------------
                                                                                      1,311,252,102      1,165,011,076
Shares repurchased...............................................................    (1,240,605,253)    (1,139,950,763)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        70,646,849         25,060,313
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
 
                                       11
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
   
6.   FEDERAL INCOME TAX  STATUS--At June 30, 1996, the  Trust had a capital loss
carryover of approximately $11,800  of which $10,900  will be available  through
June  30, 2002 and $900 will be available through June 30, 2003 to offset future
capital gains to the extent provided by regulations. During the year ended  June
30,  1996,  the  Trust had  utilized  capital loss  carryovers  of approximately
$5,100.
    
 
7.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
 
                                       12
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
  PRINCIPAL
  AMOUNT (IN                                                                                COUPON      DEMAND
  THOUSANDS)                                                                                RATE+        DATE*        VALUE
- --------------                                                                           ------------  ---------  -------------
<C>             <S>                                                                      <C>           <C>        <C>
                CALIFORNIA TAX-EXEMPT SHORT-TERM VARIABLE RATE
                MUNICIPAL OBLIGATIONS (63.1%)
  $    4,000    Big Bear Lake, Southwest Gas Corp 1993 Ser A (AMT).....................        3.30%   07/08/96   $   4,000,000
      11,970    California Alternative Energy Finance Authority, General Electric
                  Capital Corp-Arroyo Energy Ser 1993 B (AMT)..........................        3.10    07/08/96      11,970,000
                California Health Facilities Financing Authority,
       2,700      Catholic HealthCare West 1988 Ser A..................................        3.00    07/08/96       2,700,000
       3,800      Childrens Hospital of Orange County Ser 1991 (MBIA)..................        3.00    07/08/96       3,800,000
       5,360      Huntington Memorial Hospital Ser 1985................................        3.15    07/08/96       5,360,000
       6,900      Kaiser Permanente Ser 1993 A.........................................        3.00    07/08/96       6,900,000
      19,000      Memorial Health Services Ser 1994....................................        3.00    07/08/96      19,000,000
      10,000      St Francis Medical Center 1995 Ser E (MBIA)..........................        3.00    07/08/96      10,000,000
       4,570      St. Joseph Health System Ser 1985 B..................................        3.00    07/01/96       4,570,000
                California Housing Finance Agency,
       3,000      1995 Ser E (AMT).....................................................        3.50    08/01/96       3,000,000
       5,000      Home Mtg 1996 Ser J (AMT) (WI).......................................        4.00    07/24/97       5,000,000
                California Pollution Control Financing Authority,
       2,720      Chevron USA Inc Ser 1983.............................................        4.00    11/15/96       2,727,096
       7,300      Chevron USA Inc Ser 1984 B...........................................        3.70    06/16/97       7,306,129
       1,750      Noranda-Grey Eagle Mines Inc 1984 Ser B..............................        3.40    07/08/96       1,750,000
       5,000      North County Recycling Center 1991 Ser B.............................        2.80    07/08/96       5,000,000
      10,000      Pacific Gas & Electric Co Ser 1996 B (AMT)...........................        3.40    07/08/96      10,000,000
       6,700      Pacific Gas & Electric Co Ser 1996 F.................................        3.40    07/01/96       6,700,000
       7,800      Stanislaus Inc Ser 1987 (AMT)........................................        3.70    07/01/96       7,800,000
      14,000    California Public Capital Improvements Financing Authority, Pooled Ser
                  1988 C...............................................................        3.65    09/15/96      14,000,000
                California Statewide Communities Development Authority,
       5,000      House Ear Institute 1993 Ser A COPs..................................        3.35    07/01/96       5,000,000
       9,000      Kaiser Permanente Ser 1995 COPs......................................        3.00    07/08/96       9,000,000
       5,000      St Joseph Health System Grp COPs.....................................        3.00    07/01/96       5,000,000
      10,000    Foothill/Eastern Transportation Corridor Agency, Toll Road Ser 1995 C..        3.10    07/08/96      10,000,000
      10,000    Long Beach, Memorial Health Services Ser 1991..........................        3.00    07/08/96      10,000,000
       2,900    Los Angeles, Multi-Family 1985 Ser K...................................        3.10    07/08/96       2,900,000
       8,000    Los Angeles County Metropolitan Transportation Authority, Prop C Sales
                  Tax Refg Ser 1993 A (MBIA)...........................................        3.00    07/08/96       8,000,000
       5,000    Northern California Public Power Agency, Geothermal No 3 1996 Ser A
                  (AMBAC)..............................................................        3.15    07/08/96       5,000,000
       4,600    Ontario Redevelopment Agency, Daisy XX Assoc Ltd Ser 1984..............        2.90    07/08/96       4,600,000
       3,900    Redlands, Orange Village Apts 1988 Ser A (AMT).........................        3.15    07/08/96       3,900,000
      10,400    Sacramento County, Administration Center & Courthouse Ser 1990 COPs....        3.10    07/08/96      10,400,000
       6,600    San Jose-Santa Clara Clean Water Financing Authority, Sewer Ser 1995 B
                  (FGIC)...............................................................        3.15    07/08/96       6,600,000
       7,000    Santa Clara County-El Camino Hospital District Hospital Facilities
                  Authority, Valley Medical Center 1985 Ser A..........................        3.10    07/08/96       7,000,000
      14,800    Southern California Public Power Authority, Transmission 1991 Refg Ser
                  (AMBAC)..............................................................        3.10    07/08/96      14,800,000
       4,315    Tri City Housing Finance Agency, Single Family Ser 1994 (AMT)..........        4.00    07/01/96       4,315,000
       4,310    Turlock, Irrigation District Ser 1988 A................................        3.10    07/08/96       4,310,000
                                                                                                                  -------------
                TOTAL CALIFORNIA TAX-EXEMPT SHORT-TERM VARIABLE RATE
                  MUNICIPAL OBLIGATIONS (AMORTIZED COST $242,408,225)...........................................    242,408,225
                                                                                                                  -------------
</TABLE>
    
 
                                       13
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                                       YIELD TO
  PRINCIPAL                                                                                            MATURITY
  AMOUNT (IN                                                                   COUPON     MATURITY    ON DATE OF
  THOUSANDS)                                                                    RATE        DATE       PURCHASE         VALUE
- --------------                                                              ------------  ---------  -------------  -------------
<C>             <S>                                                         <C>           <C>        <C>            <C>
                CALIFORNIA TAX-EXEMPT COMMERCIAL PAPER (32.7%)
  $    6,000    California, Ser 1996......................................        3.55%   08/22/96        3.55 %    $   6,000,000
                California Department of Water Resources,
       4,400      Ser I...................................................        3.30    10/10/96        3.30          4,400,000
       4,500      Ser I...................................................        3.30    10/30/96        3.30          4,500,000
                California Pollution Control Financing Authority,
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    07/25/96        3.30          4,000,000
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    08/08/96        3.30          4,000,000
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    08/15/96        3.30          4,000,000
       2,100      Southern California Edison Co Ser 1985 B................        3.05    08/13/96        3.05          2,100,000
       3,000      Southern California Edison Co Ser 1985 A................        3.50    08/13/96        3.50          3,000,000
       3,500      Southern California Edison Co Ser 1985 A................        3.30    10/08/96        3.30          3,500,000
       2,900      Southern California Edison Co Ser 1985 A................        3.40    10/08/96        3.40          2,900,000
       5,000      Thermal Energy Dev Ptnrsp Ser A (AMT)...................        3.65    08/23/96        3.65          5,000,000
       5,000    Chula Vista, San Diego Gas & Electric Co Ser 1992 C
                  (AMT)...................................................        3.55    08/29/96        3.55          5,000,000
       5,000    Delmar Race Track Authority, 1993 BANs....................        3.35    08/15/96        3.35          5,000,000
                East Bay Municipal Utility District,
       5,500      Water...................................................        3.40    08/27/96        3.40          5,500,000
       3,500      Water...................................................        3.50    08/27/96        3.50          3,500,000
       4,000    Long Beach Harbor Department, Ser A (AMT).................        3.35    07/12/96        3.35          4,000,000
                Los Angeles Department of Water & Power,
       4,000      Electric................................................        3.55    07/31/96        3.55          4,000,000
       5,600      Electric................................................        3.45    08/21/96        3.45          5,600,000
       4,500    Metropolitan Water District of Southern California, Ser
                  1991....................................................        3.45    08/26/96        3.45          4,500,000
       6,000      Ser 1995 B..............................................        3.40    09/19/96        3.40          6,000,000
       5,000      Ser 1995 B..............................................        3.40    09/24/96        3.40          5,000,000
                Sacramento Municipal Utility District,
       3,000      Ser I...................................................        3.35    07/30/96        3.35          3,000,000
       4,000      Ser I...................................................        3.30    09/25/96        3.30          4,000,000
                San Diego,
       7,500      San Diego Gas & Electric Co Ser 1995 B..................        3.50    08/06/96        3.50          7,500,000
       4,050      San Diego Gas & Electric Co Ser 1995 A..................        3.50    10/24/96        3.50          4,050,000
                West & Central Basin Financing Authority,
       3,000      West Basin Municipal Water District TRANs...............        3.05    08/07/96        3.05          3,000,000
       4,000      West Basin Municipal Water District TRANs...............        3.50    08/19/96        3.50          4,000,000
                PUERTO RICO
       4,000    Puerto Rico Government Development Bank,..................        3.65    09/11/96        3.65          4,000,000
       4,500    Puerto Rico Government Development Bank,..................        3.60    09/18/96        3.60          4,500,000
                                                                                                                    -------------
                TOTAL CALIFORNIA TAX-EXEMPT COMMERCIAL PAPER
                  (AMORTIZED COST $125,550,000)...................................................................    125,550,000
                                                                                                                    -------------
</TABLE>
    
 
                                       14
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
                                                                                                       YIELD TO
  PRINCIPAL                                                                                            MATURITY
  AMOUNT (IN                                                                   COUPON     MATURITY    ON DATE OF
  THOUSANDS)                                                                    RATE        DATE       PURCHASE         VALUE
- --------------                                                              ------------  ---------  -------------  -------------
                CALIFORNIA TAX-EXEMPT SHORT-TERM MUNICIPAL NOTES (16.3%)
<C>             <S>                                                         <C>           <C>        <C>            <C>
  $    9,000    California School Cash Reserve Program Authority, 1995
                  Pool Ser A, dtd 07/05/95................................        4.75%   07/03/96        3.75 %    $   9,000,947
      13,000    Contra Costa County, 1996-1997 TRANs, dtd 07/01/96 (WI)...        4.50    07/03/97        3.76         13,094,110
       7,000    Riverside County, 1996-1997 Ser A TRANs, dtd 07/01/96
                  (WI)....................................................        4.50    06/30/97        3.90          7,040,250
       7,000    San Bernadino County, 1996-1997 TRANs, dtd 07/01/96
                  (WI)....................................................        4.50    06/30/97        3.875         7,042,000
      10,000    San Diego, 1996-1997 Ser A TANs, dtd 07/02/96 (WI)........        4.50    07/02/97        3.75         10,072,200
       9,000    Santa Barbara County, 1995-1996 Ser A TRANs, dtd
                  07/06/95................................................        4.50    07/05/96        3.79          9,001,009
       7,500    Ventura County, Ser 1996 TRANs, dtd 07/02/96 (WI).........        4.75    07/02/97        3.85          7,564,950
                                                                                                                    -------------
                TOTAL CALIFORNIA TAX-EXEMPT SHORT-TERM MUNICIPAL NOTES
                  (AMORTIZED COST $62,815,466)....................................................................     62,815,466
                                                                                                                    -------------
              TOTAL INVESTMENTS (AMORTIZED COST $430,773,691) (A)........................      112.1%     430,773,691
              LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS.............................      (12.1)     (46,555,527)
                                                                                           -----------   ------------
              NET ASSETS.................................................................      100.0%    $384,218,164
                                                                                           -----------   ------------
                                                                                           -----------   ------------
</TABLE>
    
 
- ------------
 
      AMT        ALTERNATIVE MINIMUM TAX.
     BANs        Bond Anticipation Notes.
     COPs        Certificates of Participation.
     TANs        Tax Anticipation Notes.
     TRANs       Tax and Revenue Anticipation Notes.
      WI         Security purchased on a when issued basis.
       +         Rate shown is rate in effect at June 30, 1996.
       *         Date in which the principal amount can be
                 recovered through demand.
      (a)        Cost is the same for federal income tax purposes.
Bond Insurance:
     AMBAC       AMBAC Indemnity Corporation.
     FGIC        Financial Guaranty Insurance Company.
     MBIA        Municipal Bond Investors Assurance Corporation.
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       15
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets California Tax-Free Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material  respects,  the  financial position  of  Active  Assets California
Tax-Free Trust (the "Trust") at June 30, 1996, the results of its operations for
the year then ended, the changes in its net assets for each of the two years  in
the period then ended and the financial highlights for each of the four years in
the  period then  ended and  for the period  November 12,  1991 (commencement of
operations) through  June  30,  1992,  in  conformity  with  generally  accepted
accounting  principles.  These  financial  statements  and  financial highlights
(hereafter referred to as "financial statements") are the responsibility of  the
Trust's  management;  our  responsibility  is to  express  an  opinion  on these
financial statements  based on  our audits.  We conducted  our audits  of  these
financial  statements in  accordance with generally  accepted auditing standards
which require that we plan and perform the audit to obtain reasonable  assurance
about  whether the  financial statements are  free of  material misstatement. An
audit includes examining, on a test  basis, evidence supporting the amounts  and
disclosures  in the  financial statements,  assessing the  accounting principles
used and significant estimates  made by management,  and evaluating the  overall
financial  statement presentation.  We believe  that our  audits, which included
confirmation of securities at June 30, 1996 by correspondence with the custodian
and brokers, provide a reasonable basis for the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                      1996 FEDERAL TAX NOTICE (UNAUDITED)
During the year ended June 30, 1996,  the Trust paid to shareholders $0.028  per
share  from  net  investment  income.  All of  the  Trust's  dividends  from net
investment income were exempt interest  dividends, excludable from gross  income
for Federal income tax purposes.
 
                                       16
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
 
       TWO WORLD TRADE CENTER, NEW YORK, NEW YORK 10048 - (212) 392-5000
 
    Active Assets Government Securities Trust (the "Government Securities Trust"
or  the  "Trust")  is  a  no-load,  diversified  open-end  management investment
company. The Trust is authorized to reimburse Dean Witter Distributors Inc.  for
specific  expenses incurred in promoting the  distribution of the Trust's shares
pursuant to a Plan of Distribution  pursuant to Rule 12b-1 under the  Investment
Company  Act of  1940, as  amended (the  "Act"). Reimbursement  may in  no event
exceed an amount equal to  payments at the annual rate  of 0.15% of the  average
daily net assets of the Trust.
 
    The investment objectives of the Trust are high current income, preservation
of  capital and liquidity.  The Trust will  seek to achieve  these objectives by
investing in  a diversified  portfolio of  short-term money  market  instruments
issued  or  guaranteed  by  the  United States  Government  or  its  agencies or
instrumentalities.
 
    AN INVESTMENT IN  THE TRUST IS  NEITHER INSURED NOR  GUARANTEED BY THE  U.S.
GOVERNMENT.  THERE IS  NO ASSURANCE THAT  THE TRUST  WILL BE ABLE  TO MAINTAIN A
STABLE NET ASSET VALUE OF $1.00 PER SHARE.
 
    SHARES OF THE  TRUST ARE NOT  DEPOSITS OR OBLIGATIONS  OF, OR GUARANTEED  OR
ENDORSED  BY, ANY BANK, AND THE SHARES  ARE NOT FEDERALLY INSURED BY THE FEDERAL
DEPOSIT INSURANCE CORPORATION, THE FEDERAL RESERVE BOARD, OR ANY OTHER AGENCY.
 
                               TABLE OF CONTENTS
 
   
<TABLE>
<S>                                                 <C>
Highlights/2                                        How Net Asset Value is Determined/A-4
Summary of Trust Expenses/3                         Confirmations/A-5
Financial Highlights/3                              The Trusts and Their Management/A-5
Investment Objectives and Policies/4                Plan of Distribution/A-6
Financial Statements -- June 30, 1996/6             Dividends, Distributions and Taxes/A-6
Report of Independent Accountants/10                General Information/A-9
Purchase and Redemption of Shares/A-1               Voting Rights/A-9
    Purchase of Shares/A-1                          Custodian/A-10
    Purchase of Shares by Non-Participants in       Shareholder Inquiries/A-10
      Active Assets Program/A-2
    Redemption of Shares/A-3
    Redemption of Shares by Non-Participants in
      Active Assets Program/A-4
</TABLE>
    
 
   
    THIS PROSPECTUS SETS FORTH CONCISELY THE INFORMATION YOU SHOULD KNOW  BEFORE
INVESTING  IN THE TRUST.  IT SHOULD BE  READ AND RETAINED  FOR FUTURE REFERENCE.
ADDITIONAL INFORMATION  ABOUT  THE  TRUST  IS  CONTAINED  IN  THE  STATEMENT  OF
ADDITIONAL  INFORMATION, DATED  AUGUST 22, 1996,  WHICH HAS BEEN  FILED WITH THE
SECURITIES AND EXCHANGE  COMMISSION, AND WHICH  IS AVAILABLE AT  NO CHARGE  UPON
REQUEST  OF THE  TRUST AT  THE ADDRESS  LISTED ABOVE  OR BY  CALLING DEAN WITTER
INTERCAPITAL  INC.  (THE  "INVESTMENT  MANAGER"  OR  "INTERCAPITAL")  AT   (212)
392-2550.  THE  STATEMENT OF  ADDITIONAL INFORMATION  IS INCORPORATED  HEREIN BY
REFERENCE.
    
 
    THE INFORMATION IN THIS  PROSPECTUS SHOULD BE READ  IN CONJUNCTION WITH  THE
INFORMATION APPEARING ELSEWHERE IN THIS DOCUMENT, INCLUDING THE APPENDIX HERETO,
WHICH IS PART OF THIS PROSPECTUS, AND IN THE DEAN WITTER CLIENT AGREEMENT.
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
     EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
        SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
            COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF
                   THIS PROSPECTUS. ANY REPRESENTATION TO THE
                        CONTRARY IS A CRIMINAL OFFENSE.
                            ------------------------
 
   
                THE DATE OF THIS PROSPECTUS IS AUGUST 22, 1996.
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
    
<PAGE>
HIGHLIGHTS
 
   
<TABLE>
<S>                    <C>
THE                    A  no-load, open-end diversified management investment  company investing principally in short-term
TRUST                  money market instruments issued or  guaranteed by the United States  Government or its agencies  or
                       instrumentalities.  The Trust is authorized to reimburse Dean Witter Distributors Inc. for specific
                       expenses incurred  in promoting  the distribution  of  the Trust's  shares pursuant  to a  Plan  of
                       Distribution  pursuant to Rule 12b-1  under the Act. (see  page A-6). The Trust  is organized as an
                       unincorporated business trust under the laws of Massachusetts. (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
SHARES                 The shares of  the Government Securities  Trust are offered  to participants in  the Active  Assets
OFFERED                program  of Dean Witter and to non-participants who wish  to invest directly in shares of the Trust
                       (See page A-2). The  primary components of  the Active Assets program  are the Securities  Account,
                       which  is linked to  the Active Assets Insured  Account, the Active Assets  Money Trust, the Active
                       Assets Tax-Free Trust,  the Active Assets  California Tax-Free Trust  or the Government  Securities
                       Trust, and to the Visa Account. See the Dean Witter Client Agreement for further information.
- ------------------------------------------------------------------------------------------------------------------------
PURCHASE               Pursuant to the Dean Witter Client Agreement between Dean Witter and the customer, free credit cash
OF SHARES              balances  in an Active  Assets account will automatically  be invested in  shares of the Government
                       Securities Trust daily at their net asset value without any sales charge. Dean Witter  Distributors
                       Inc.  is  the  Distributor of  shares  of  the Trust.  Investments  in  shares are  made  under the
                       circumstances described under "Purchase and Redemption of Shares" (see page A-1).  Non-participants
                       in the Active Assets program should refer to the discussion appearing at page A-2.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             High  current income, preservation of capital and liquidity (see page 4). There can be no assurance
OBJECTIVES             that the Trust's investment objectives will be achieved.
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             A diversified portfolio of short-term money market  instruments issued or guaranteed by the  United
POLICY                 States Government or its agencies or instrumentalities (see page 4).
- ------------------------------------------------------------------------------------------------------------------------
INVESTMENT             Dean  Witter  InterCapital  Inc.,  the  Investment  Manager  of  the  Trust,  and  its wholly-owned
MANAGER                subsidiary, Dean Witter Services Company, Inc.,  serve in various investment management,  advisory,
                       management  and administrative capacities to ninety-eight investment companies and other portfolios
                       with assets under management of approximately $84.6 billion at June 30, 1996 (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
MANAGEMENT             Monthly fee at an annual rate of 1/2 of 1% of average daily net assets, scaled down on assets  over
FEE                    $500 million (see page A-5).
- ------------------------------------------------------------------------------------------------------------------------
DISTRIBUTOR            Dean  Witter Distributors Inc.  (the "Distributor") sells  shares of the  Trust through Dean Witter
                       Reynolds Inc.  Other  than  the  reimbursement  to the  Distributor  pursuant  to  the  Rule  12b-1
                       Distribution Plan, the Distributor receives no distribution fees (see page A-2).
- ------------------------------------------------------------------------------------------------------------------------
PLAN OF                The  Trust is authorized to  reimburse specific expenses incurred  in promoting the distribution of
DISTRIBUTION           the Trust's shares pursuant to a plan of  Distribution with the Distributor pursuant to Rule  12b-1
                       under  the Investment Company Act of 1940. Reimbursement may  in no event exceed an amount equal to
                       payments at the annual rate of 0.15 of 1% of average daily net assets of the Trust (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
DIVIDENDS              Automatically reinvested daily in additional shares at net asset value (see page A-6).
- ------------------------------------------------------------------------------------------------------------------------
REPORTS                Individual monthly account statements  from Dean Witter on  the Dean Witter Transaction  Statement;
                       annual and semi-annual Trust financial statements.
- ------------------------------------------------------------------------------------------------------------------------
REDEMPTION             For  participants in the Active  Assets program, shares of the  Government Securities Trust will be
OF SHARES              redeemed at net  asset value  automatically to  satisfy debit  balances in  the securities  account
                       created  by activity therein  or to satisfy amounts  owing in the Visa  Account resulting from Visa
                       card purchases, cash advances or checks written  against the Visa Account. Non-participants in  the
                       Active  Assets program should refer to the discussion appearing at page A-4. It is anticipated that
                       the net asset value will remain constant at $1.00 per share. Dean Witter has the right to terminate
                       a shareholder's Active  Assets service, in  which event all  Trust shares held  in a  shareholder's
                       account  will be involuntarily redeemed. The Trust also  reserves the right to reduce the number of
                       shares in all accounts if  the Trustees determine that this  is necessary to maintain the  constant
                       $1.00 per share net asset value. See "Purchase and Redemption of Shares" (page A-1).
- ------------------------------------------------------------------------------------------------------------------------
RISKS                  The  Trust invests principally in  high quality, short-term securities  issued or guaranteed by the
                       U.S. Government or its agencies or instrumentalities which  are subject to minimal risk of loss  of
                       income  and  principal. However,  the investor  is directed  to the  discussion under  the captions
                       "Investment Objectives and Policies" (page 4),  "Repurchase Agreements" (page 5), and  "When-Issued
                       and  Delayed Delivery  Securities" (page  5) concerning  the risks  associated with  such portfolio
                       securities and management strategies.
- ------------------------------------------------------------------------------------------------------------------------
    THE SUMMARY INFORMATION ABOVE SHOULD BE READ IN CONJUNCTION WITH THE DETAILED INFORMATION APPEARING ELSEWHERE IN  THIS
PROSPECTUS,  INCLUDING THE APPENDIX HERETO, IN THE DEAN WITTER CLIENT AGREEMENT AND IN THE TRUST'S STATEMENT OF ADDITIONAL
INFORMATION, INCLUDING THE APPENDIX THERETO.
</TABLE>
    
 
                                       2
 
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
SUMMARY OF TRUST EXPENSES
- --------------------------------------------------------------------------------
 
    The  following table illustrates all expenses and fees that a shareholder of
the Trust will incur. The expenses and fees  set forth in the table are for  the
fiscal year ended June 30, 1996.
 
<TABLE>
<S>                                       <C>
SHAREHOLDER TRANSACTION EXPENSES
Maximum Sales Charge Imposed on
 Purchases..............................    None
Maximum Sales Charge Imposed on
 Reinvested Dividends...................  None
Deferred Sales Charge...................  None
Redemption Fees.........................  None
Exchange Fee............................  None
ANNUAL TRUST OPERATING EXPENSES (AS A
 PERCENTAGE OF AVERAGE NET ASSETS)
Management Fees.........................    0.49%
12b-1 Fees..............................    0.10%
Other Expenses..........................    0.06%
                                          -------
Total Trust Operating Expenses..........    0.65%
                                          -------
                                          -------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                          10
EXAMPLE                                   1 YEAR    3 YEARS   5 YEARS    YEARS
- ----------------------------------------  -------   -------   -------   -------
<S>                                       <C>       <C>       <C>       <C>
You would pay the following expenses on
  a $1,000 investment, assuming (1) 5%
  annual return and (2) redemption at
  the end of each time period:              $ 7       $21       $36       $81
</TABLE>
 
    Dean Witter charges an annual Active Assets program participation fee of $80
($100 for corporate participants). Shareholders of the Trust who are not program
participants will not be charged an Active Assets program fee.
 
    The  above  example should  not be  considered a  representation of  past or
future expenses or performance. Actual expenses  of the Trust may be greater  or
less than those shown.
 
    The  purpose of this  table is to  assist the investor  in understanding the
various costs and expenses that an investor  in the Trust will bear directly  or
indirectly.  For a  more complete description  of these costs  and expenses, see
pages A-5 and A-6 in the Appendix to this Prospectus.
 
FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------
 
   
    The following ratios and per share  data for a share of beneficial  interest
outstanding  throughout each period  have been audited  by Price Waterhouse LLP,
independent accountants. The financial highlights should be read in  conjunction
with  the financial statements  and notes thereto and  the unqualified report of
independent accountants which  are contained  in this  Prospectus commencing  on
page 6.
    
 
   
<TABLE>
<CAPTION>
                                                                   FOR THE YEAR ENDED JUNE 30,
                                -------------------------------------------------------------------------------------------------
                                 1996      1995      1994      1993      1992      1991      1990      1989      1988      1987
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
<S>                             <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>       <C>
PER SHARE OPERATING PERFORMANCE:
Net asset value, beginning of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net investment income.........   0.049     0.048     0.027     0.027     0.043     0.065     0.077     0.079     0.062     0.055
Less dividends from net
 investment income............  (0.049)   (0.048)   (0.027)   (0.027)   (0.043)   (0.065)   (0.077)   (0.079)   (0.062)   (0.055)
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
Net asset value, end of
 period.......................  $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00    $ 1.00
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
                                -------   -------   -------   -------   -------   -------   -------   -------   -------   -------
TOTAL INVESTMENT RETURN+......    5.03%     4.92%     2.76%     2.71%     4.37%     6.72%     8.03%     8.20%     6.41%     5.62%
RATIOS TO AVERAGE NET ASSETS:
  Expenses....................    0.65%     0.67%     0.66%     0.66%     0.68%     0.70%     0.68%     0.70%     0.68%     0.70%
  Net investment income.......    4.93%     4.84%     2.72%     2.68%     4.28%     6.39%     7.74%     7.94%     6.22%     5.47%
SUPPLEMENTAL DATA:
Net assets, end of period, in
 millions.....................    $571      $542      $472      $509      $533      $597      $300      $244      $236      $177
<FN>
- -----------------
+  CALCULATED BASED ON  THE NET ASSET VALUE  AS OF THE LAST  BUSINESS DAY OF THE
PERIOD.
</TABLE>
    
 
                                       3
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
INVESTMENT OBJECTIVES AND POLICIES
- --------------------------------------------------------------------------------
 
    THE INVESTMENT OBJECTIVES OF THE TRUST ARE HIGH CURRENT INCOME, PRESERVATION
OF CAPITAL AND LIQUIDITY.
 
    The  Trust seeks to  achieve its objectives by  investing in U.S. Government
securities, including a variety of securities which are issued or guaranteed  by
the United States Treasury, by various agencies of the United States Government,
and by various instrumentalities which have been established or sponsored by the
United  States Government,  and certain  interests in  the foregoing securities.
Except for U.S.  Treasury securities,  these obligations, even  those which  are
guaranteed by Federal agencies or instrumentalities, may or may not be backed by
the  "full faith and credit" of the United States. In the case of securities not
backed by the full faith and credit of the United States, they may be backed, in
part, by a line of credit with  the U.S. Treasury (such as the Federal  National
Mortgage  Association),  or  the  Trust  must  look  to  the  agency  issuing or
guaranteeing the obligation for  ultimate repayment (such  as securities of  the
Federal  Farm Credit System) in which case the Trust may not be able to assert a
claim  against  the   United  States  itself   in  the  event   the  agency   or
instrumentality does not meet its commitments.
 
    Treasury  securities  include  Treasury  bills,  Treasury  coupons, Treasury
notes, and Treasury bonds (including zero coupon bonds). Some of the  Government
agencies  and instrumentalities which issue  or guarantee securities include the
Federal Farm Credit System, the Federal  Home Loan Banks, the Federal Home  Loan
Mortgage  Corporation, the Government National Mortgage Association, the Federal
National Mortgage Association, the Farmers Home Administration, the Federal Land
Banks, the Small  Business Administration, the  Export-Import Bank, the  Federal
Intermediate Credit Banks and the Banks for Cooperatives.
 
    The  Trust may invest  in securities issued  or guaranteed by  any agency or
instrumentality established or sponsored by  the United States Government.  Such
investments  may  take  the  form  of participation  interests  in,  and  may be
evidenced by  deposit  or  safekeeping  receipts  for,  any  of  the  foregoing.
Participation  interests are  pro rata  interests in  U.S. Government securities
held by others such as  interests in pools of  mortgages sold by the  Government
National Mortgage Association; instruments evidencing deposit or safekeeping are
documentary receipts for such original securities held in custody by others.
 
    The  Federal Deposit  Insurance Corporation is  the administrative authority
over the  Bank Insurance  Fund and  the  Savings Insurance  Fund which  are  the
agencies  of  the U.S.  Government which  insure  (including both  principal and
interest) the deposits of certain banks and savings and loan associations up  to
$100,000  per deposit. Current federal regulations also permit such institutions
to issue insured negotiable certificates of deposit ("CDs") in principal amounts
of $100,000  or more  without regard  to  the interest  rate ceilings  on  other
deposits.  To  remain  fully insured  as  to principal,  these  investments must
currently be limited to $100,000 per  bank or savings and loan association.  The
interest on such investments is not insured. The Trust may invest in such CDs of
banks  and  savings  and loan  institutions  having  total assets  of  less than
$1,000,000,000, limited to the  insured amount of  principal ($100,000) in  each
case  and limited with  regard to all such  CDs and all  illiquid assets, in the
aggregate, to 10% of the Trust's total assets.
 
    The Trust intends  normally to  hold its portfolio  securities to  maturity.
Historically,  securities issued  or guaranteed  by the  U.S. Government  or its
agencies and instrumentalities have involved  minimal risk of loss of  principal
or interest, if held to maturity.
 
    The Trust may not borrow money, except from banks for temporary or emergency
purposes,  including the  meeting of  redemption requests  which might otherwise
require the  untimely disposition  of securities.  Borrowing in  the  aggregate,
including  reverse repurchase agreements, may not  exceed 20%, and borrowing for
purposes other than meeting redemptions  may not exceed 5%  of the value of  the
Trust's  total  assets (including  the amount  borrowed), less  liabilities (not
including
 
                                       4
 
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
the amount borrowed) at the time the borrowing is made.
 
    The investment  objectives and  policies  stated above  may not  be  changed
without  shareholder approval. There is no assurance that the Trust's objectives
will be achieved.
 
PORTFOLIO MANAGEMENT
 
    REPURCHASE AGREEMENTS.   The  Trust may  enter into  repurchase  agreements,
which  may  be viewed  as a  type of  secured  lending by  the Trust,  and which
typically involve the acquisition by the  Trust of government securities from  a
selling  financial institution such  as a bank, savings  and loan association or
broker-dealer. The  agreement provides  that the  Trust will  sell back  to  the
institution,  and that the institution  will repurchase, the underlying security
("collateral") at a specified price and at a fixed time in the future. The Trust
will accrue interest from the institution until the time when the repurchase  is
to occur. Although such date is deemed by the Trust to be the maturity date of a
repurchase  agreement,  the  maturities  of  securities  subject  to  repurchase
agreements are not subject to any  limits and may exceed thirteen months.  While
repurchase   agreements  involve  certain  risks   not  associated  with  direct
investments in U.S. Government securities, the Trust follows procedures designed
to  minimize  such   risks.  These  procedures   include  effecting   repurchase
transactions  only with large,  well capitalized and  well established financial
institutions and specifying the required value of the collateral underlying  the
agreement.
 
    WHEN-ISSUED   AND  DELAYED  DELIVERY  SECURITIES.  The  Trust  may  purchase
securities on  a  when-issued or  delayed  delivery basis;  i.e.,  delivery  and
payment  can take place a month or more  after the date of the transaction. When
such transactions are negotiated, the price is fixed at the time of  commitment,
but delivery and payment can take place between one month and 120 days after the
date  of the commitment. These securities  are subject to market fluctuation and
no interest accrues to the purchaser during  this period. At the time the  Trust
makes the commitment to purchase securities on a when-issued or delayed delivery
basis,  it will  record the transaction  and thereafter reflect  the value, each
day, of such security in determining its net
asset value.
 
    All the  foregoing  strategies may  subject  the  Trust to  the  effects  of
interest  rate  fluctuations  to  a  greater extent  than  would  occur  if such
strategies were not used. While such strategies listed above may be used by  the
Trust if, in the opinion of the Investment Manager, they will be advantageous to
the  Trust, the Trust will be free to reduce or eliminate its activity in any of
these areas  without  changing  its  fundamental  investment  policies.  Certain
provisions of the Internal Revenue Code, related regulations, and rulings of the
Internal  Revenue Service  may also  have the effect  of reducing  the extent to
which the  previously  cited  techniques  may  be  used  by  the  Trust,  either
individually  or in combination. Furthermore, there  is no assurance that any of
these strategies or any other strategies and methods available to the Trust will
result in the achievement of its objectives.
 
    The Trust  will  invest  in  securities of  varying  maturities  and  risks,
although  it will not  invest in securities  with an effective  maturity of more
than one year.  The Trust  will generally  not seek  profits through  short-term
trading, although it may dispose of any portfolio security prior to maturity if,
on the basis of a revised evaluation or other circumstance or consideration, the
Investment Manager deems such disposition advisable.
 
    The  Trust is expected  to have a  high portfolio turnover  due to the short
maturities of securities  purchased, but this  should not affect  income or  net
asset value as brokerage commissions are not normally charged on the purchase or
sale of money market instruments such as U.S. Government obligations.
 
    BROKERAGE ALLOCATION.  Brokerage commissions are not normally charged on the
purchase   or  sale  of  money  market   instruments  such  as  U.S.  Government
obligations, but such transactions may involve transaction costs in the form  of
spreads between bid and asked prices. Pursuant to an order of the Securities and
Exchange  Commission,  the Trust  may effect  principal transactions  in certain
money market instruments  with Dean  Witter. In  addition, the  Trust may  incur
brokerage commissions on transactions conducted through Dean Witter.
 
                                       5
 
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
<TABLE>
<S>                                            <C>
ASSETS:
Investments in securities, at value
  (amortized cost $571,666,258)..............  $ 571,666,258
Cash.........................................         90,000
Interest receivable..........................             93
Prepaid expenses and other assets............         21,226
                                               -------------
        TOTAL ASSETS.........................    571,777,577
                                               -------------
LIABILITIES:
Payable for:
  Investment management fee..................        220,885
  Plan of distribution fee...................         45,223
  Shares of beneficial interest
    repurchased..............................             92
Accrued expenses and other payables..........        111,289
                                               -------------
        TOTAL LIABILITIES....................        377,489
                                               -------------
NET ASSETS:
Paid-in-capital..............................    571,399,751
Accumulated undistributed net investment
  income.....................................            337
                                               -------------
        NET ASSETS...........................  $ 571,400,088
                                               -------------
                                               -------------
NET ASSET VALUE PER SHARE, 571,399,751 shares
 outstanding (unlimited shares authorized of
 $.01 par value).............................
                                                       $1.00
                                               -------------
                                               -------------
</TABLE>
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                             <C>
NET INVESTMENT INCOME:
INTEREST INCOME...............................  $32,406,748
                                                -----------
EXPENSES
  Investment management fee...................    2,841,130
  Plan of distribution fee....................      570,309
  Transfer agent fees and expenses............      121,843
  Registration fees...........................      110,736
  Professional fees...........................       45,683
  Shareholder reports and notices.............       37,493
  Custodian fees..............................       33,551
  Trustees' fees and expenses.................       17,577
  Other.......................................        8,619
                                                -----------
      TOTAL EXPENSES..........................    3,786,941
                                                -----------
      NET INVESTMENT INCOME AND NET INCREASE..  $28,619,807
                                                -----------
                                                -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                   JUNE 30, 1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income and net increase.....................................    $   28,619,807      $   25,276,044
    Dividends from net investment income.......................................       (28,619,562)        (25,276,526)
    Net increase from transactions in shares of beneficial interest............        29,180,773          70,718,948
                                                                                 ------------------  ------------------
        Total increase.........................................................        29,181,018          70,718,466
NET ASSETS:
  Beginning of period..........................................................       542,219,070         471,500,604
                                                                                 ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $337 and $92,
   respectively)...............................................................    $  571,400,088      $  542,219,070
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       6
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.   ORGANIZATION  AND ACCOUNTING POLICIES--Active  Assets Government Securities
Trust (the "Trust") is registered under  the Investment Company Act of 1940,  as
amended  (the "Act"), as a  diversified, open-end management investment company.
The Trust's  investment  objectives are  high  current income,  preservation  of
capital and liquidity. The Trust was organized as a Massachusetts business trust
on March 30, 1981 and commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that affect  the reported  amounts and  disclosures. Actual results
could differ from  those estimates. The  following is a  summary of  significant
accounting policies:
 
    A.   VALUATION OF INVESTMENTS--Portfolio  securities are valued at amortized
    cost, which approximates market value.
 
    B.  ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for  on
    the  trade date (date the order to  buy or sell is executed). Realized gains
    and losses on security  transactions are determined  by the identified  cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.   FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies and to distribute all of its taxable and nontaxable income to  its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement with Dean  Witter InterCapital  Inc. (the  "Investment Manager"),  the
Trust  pays the Investment  Manager a management fee,  accrued daily and payable
monthly, by applying the following annual rates  to the net assets of the  Trust
determined  as of the close of each business  day: 0.50% to the portion of daily
net assets not exceeding $500 million; 0.425% to the portion of daily net assets
exceeding $500 million but not exceeding $750 million; 0.375% to the portion  of
daily  net assets exceeding $750 million but  not exceeding $1 billion; 0.35% to
the portion of  daily net  assets exceeding $1  billion but  not exceeding  $1.5
billion;  0.325% to the portion  of daily net assets  exceeding $1.5 billion but
not exceeding $2 billion; 0.30% to the portion of daily net assets exceeding  $2
billion  but not  exceeding $2.5  billion; 0.275%  to the  portion of  daily net
assets exceeding $2.5  billion but not  exceeding $3 billion;  and 0.25% to  the
portion of daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
                                       7
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the  Trustees  determine  to  reimburse,  as  described  below.  The   following
activities   and  services  may  be  provided   by  the  Distributor  and  other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average  daily net assets during the month. Expenses incurred by the Distributor
pursuant to the  Plan in any  fiscal year will  not be reimbursed  by the  Trust
through  payments accrued in any subsequent fiscal year. For the year ended June
30, 1996, the distribution fee was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases  and proceeds  from sales/maturities  of portfolio  securities for the
year  ended  June  30,   1996  aggregated  $7,798,198,359  and   $7,800,002,083,
respectively.
 
    Dean  Witter  Trust  Company, an  affiliate  of the  Investment  Manager and
Distributor, is the  Trust's transfer  agent. At June  30, 1996,  the Trust  had
transfer agent fees and expenses payable of approximately $8,800.
 
    The  Trust  has an  unfunded  noncontributory defined  benefit  pension plan
covering all  independent  Trustees  of  the  Trust  who  will  have  served  as
independent Trustees for at least five years at the time of retirement. Benefits
under  this plan are based on years  of service and compensation during the last
five years of service. Aggregate pension costs for the year ended June 30,  1996
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $1,096. At  June 30,  1996, the  Trust had  an accrued  pension liability  of
$48,883  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     2,060,055,907      1,974,285,922
Shares issued in reinvestment of dividends.......................................        28,586,199         25,245,423
                                                                                   -----------------  -----------------
                                                                                      2,088,642,106      1,999,531,345
Shares repurchased...............................................................    (2,059,461,333)    (1,928,812,397)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        29,180,773         70,718,948
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
6.   SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table on
page 3 of this Prospectus.
 
                                       8
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                              ANNUALIZED
 PRINCIPAL                                                                                      YIELD
AMOUNT (IN                                  DESCRIPTION AND                                   ON DATE OF
THOUSANDS)                                   MATURITY DATES                                    PURCHASE        VALUE
- -----------  ------------------------------------------------------------------------------  ------------  -------------
<C>          <S>                                                                             <C>           <C>
             U.S. GOVERNMENT AGENCIES (99.1%)
 $ 101,925   Federal Farm Credit Bank
               07/11/96 - 12/02/96.........................................................  4.86 - 5.55%  $ 100,763,284
   220,240   Federal Home Loan Banks
               07/01/96 - 12/17/96.........................................................  4.95 - 5.54     217,770,349
   113,336   Federal Home Loan Mortgage Corp.
               07/03/96 - 09/27/96.........................................................  5.22 - 5.42     112,502,650
   119,555   Federal National Mortgage Assoc.
               07/03/96 - 10/11/96.........................................................  4.99 - 5.42     118,583,575
     7,000   Student Loan Marketing Assoc.
               07/01/96....................................................................      5.52          6,997,853
    10,000   Tennessee Valley Authority
               08/29/96....................................................................      5.37          9,910,025
                                                                                                           -------------
             TOTAL U.S. GOVERNMENT AGENCIES (AMORTIZED COST $566,527,736)................................    566,527,736
                                                                                                           -------------
             U.S. GOVERNMENT OBLIGATION (0.9%)
     5,000   U.S. Treasury Bill 10/17/96 (Amortized Cost $4,919,945).........................        5.53         4,919,945
                                                                                                              -------------
             REPURCHASE AGREEMENT (0.1%)
       219   The Bank of New York due 07/01/96 (dated 06/28/96; proceeds $218,670;
               collateralized by $146,249 U.S. Treasury Note due 07/31/98 valued at $146,876
               and $76,368 U.S. Treasury Note due 11/30/97 valued at $76,073) (Identified
               Cost $218,577)................................................................       5.125           218,577
                                                                                                              -------------
             TOTAL INVESTMENTS (AMORTIZED COST $571,666,258) (A).............................       100.1%      571,666,258
             LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS..................................        (0.1)         (266,170)
                                                                                                   ------     -------------
             NET ASSETS......................................................................       100.0%    $ 571,400,088
                                                                                                   ------     -------------
                                                                                                   ------     -------------
</TABLE>
    
 
- ------------
(A) COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       9
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets Government Securities Trust
 
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material  respects,  the  financial position  of  Active  Assets Government
Securities Trust (the "Trust") at June  30, 1996, the results of its  operations
for the year then ended, the changes in its net assets for each of the two years
in  the period then ended and the financial highlights for each of the ten years
in the  period then  ended,  in conformity  with generally  accepted  accounting
principles.  These  financial  statements  and  financial  highlights (hereafter
referred to as  "financial statements")  are the responsibility  of the  Trust's
management;  our  responsibility is  to express  an  opinion on  these financial
statements based  on our  audits. We  conducted our  audits of  these  financial
statements  in  accordance  with  generally  accepted  auditing  standards which
require that we plan and perform the audit to obtain reasonable assurance  about
whether  the financial  statements are free  of material  misstatement. An audit
includes examining,  on  a  test  basis, evidence  supporting  the  amounts  and
disclosures  in the  financial statements,  assessing the  accounting principles
used and significant estimates  made by management,  and evaluating the  overall
financial  statement presentation.  We believe  that our  audits, which included
confirmation  of  securities  at  June  30,  1996  by  correspondence  with  the
custodian, provide a reasonable basis for the opinion expressed above.
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                                       10
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
                                    APPENDIX
 
    THIS  APPENDIX CONSTITUTES  PART OF  THE PROSPECTUSES  OF THE  ACTIVE ASSETS
MONEY TRUST (THE "MONEY TRUST"), THE ACTIVE ASSETS TAX-FREE TRUST (THE "TAX-FREE
TRUST"), THE ACTIVE ASSETS CALIFORNIA  TAX-FREE TRUST (THE "CALIFORNIA  TAX-FREE
TRUST")  AND  THE ACTIVE  ASSETS  GOVERNMENT SECURITIES  TRUST  (THE "GOVERNMENT
SECURITIES TRUST"). THE MONEY TRUST, THE TAX-FREE TRUST, THE CALIFORNIA TAX-FREE
TRUST AND  THE GOVERNMENT  SECURITIES TRUST  ARE REFERRED  TO IN  THIS  APPENDIX
COLLECTIVELY  AS THE "TRUSTS".  UNLESS OTHERWISE INDICATED,  THE INFORMATION SET
FORTH HEREIN IS APPLICABLE TO EACH TRUST.
 
PURCHASE AND REDEMPTION OF SHARES
- --------------------------------------------------------------------------------
 
PURCHASE OF SHARES
 
    The shares of the  Trusts are offered to  participants in the Active  Assets
financial  service program (non-participants see  below). Persons subscribing to
the program  will have  the free  credit cash  balances in  their Active  Assets
securities  account invested in  shares of the Money  Trust, the Tax-Free Trust,
the California Tax-Free Trust or the Government Securities Trust or deposited in
the Active  Assets  Insured Account  (a  Federal Deposit  Insurance  Corporation
insured  bank  account),  depending  upon  which  investment  vehicle  has  been
designated by the participant. For  further information consult the Dean  Witter
Client Agreement.
 
    Purchases  of shares of the Trusts by program participants will be made only
pursuant to the Active Assets automatic purchase procedures described below.
 
    Subscribers to  Active  Assets  services  have  the  option  to  change  the
designation  of their Trust at  any time by notifying  their Dean Witter Account
Executive.
 
    The purchase price for shares of the Trusts is the net asset value per share
next determined after receipt by  a Trust of a  purchase order, pursuant to  the
Active  Assets program, in proper form. The Trusts anticipate that the net asset
value will remain constant at $1.00 per share and that any fluctuations in value
will be reflected in the daily dividend  or in the number of outstanding  shares
in  the shareholder's account rather than in the per share dollar value. The net
asset value is determined at  12 noon, New York time,  on each day that the  New
York   Stock  Exchange  is  open  for  business,  immediately  after  the  daily
declaration of dividends or  on each other  day in which  there is a  sufficient
degree of trading in the Trust's portfolio securities that the current net asset
value of the Trust's shares might be materially affected by changes in the value
of  such portfolio securities, but only if on any such day the Trust is required
by the  provisions of  the Active  Assets program  to purchase  or redeem  Trust
shares or receives a request from a non-participant in the Active Assets program
to  purchase or redeem  shares of the  Trust. Shares purchased  will receive the
next dividend declared after  such shares are issued  which will be  immediately
prior  to the 12 noon pricing on the following business day. The net asset value
per share will not be  determined on Good Friday and  on such other federal  and
non-federal holidays as are observed by the New York Stock Exchange.
 
    A  purchase order will not be effective until Federal funds become available
to the  Trusts. Federal  funds are  a commercial  bank's deposits  in a  Federal
Reserve  Bank and can be  transferred from one member  bank's account to that of
another member bank on the  same day and thus  are considered to be  immediately
available  funds. There  are no minimum  investment requirements  for the Trusts
(with the exception of non-participants in the Active Assets Program--see below)
although the  minimum requirement  for entry  in the  Active Assets  program  is
currently  $10,000 in cash and/or securities.  Dean Witter reserves the right to
alter or
 
                                      A-1
<PAGE>
waive the conditions upon which an Active Assets account may be opened.
 
    Free credit  cash  balances  held  in  an  Active  Assets  account  will  be
automatically  invested daily in shares of  either the Money Trust, the Tax-Free
Trust, the California Tax-Free  Trust or the Government  Securities Trust, if  a
Trust  has been selected for investment by the participant, on each business day
on which the New York Stock Exchange is open. Free credit cash balances will  be
invested in shares at the price next determined, which is 12 noon New York time,
on  the next business day following the credit of any such amounts to the Active
Assets account. Free credit balances arising from a cash payment into an  Active
Assets  account  shall be  so invested  unless  such payment  is made  after the
cashiering deadline of the Dean Witter office  in which the payment is made,  in
which  case the resulting  free credit balance  shall be invested  on the second
following business day  and the  investor will  not receive  the daily  dividend
which  would have been received had such balance been invested in the designated
Trust. An Active Assets participant desiring to make such a cash payment  should
contact  his or her Dean Witter Account Executive for information concerning the
local  office's  cashiering  deadline,  which  is  dependent  on  such  office's
arrangements with its commercial banks.
 
    Each  Trust  has  entered into  a  Distribution Agreement  with  Dean Witter
Distributors Inc. (the "Distributor"), an  affiliate of InterCapital, which  has
its  principal executive offices at  Two World Trade Center,  New York, New York
10048. The  Distribution  Agreements obligate  the  Distributor to  pay  certain
expenses  in connection with the offering of the shares of the Trusts, including
costs involved  in the  distribution  of prospectuses  and periodic  reports  to
investors,  other supplementary sales literature and advertising costs. However,
costs and expenses incurred by the  Distributor may be reimbursed by the  Trusts
pursuant  to the provisions of the  respective Plans of Distribution pursuant to
Rule 12b-1 (see page A-6).
 
    From time to time, certain state administrative agencies may raise questions
as to whether  the operation of  the Active Assets  program constitutes  banking
under  the laws of  their state. In  addition, legislation has  been proposed in
certain states which,  if enacted, could  require a modification  of the  Active
Assets  program in those states.  The Distributor and Dean  Witter are not banks
and believe that the operation of the Active Assets program does not  constitute
banking  under the laws of any state.  The Distributor and Dean Witter intend to
fully contest and resist any regulatory or legislative challenges to the  Active
Assets  program.  Final adverse  rulings  in any  state  that the  Active Assets
program constitutes unauthorized banking therein or the adoption of  legislation
by  any state  affecting the  Active Assets  program could  force the  Trusts to
liquidate shares of residents in such state or to cease offering their shares in
such state as part of the Active Assets program.
 
PURCHASE OF SHARES BY NON-PARTICIPANTS IN ACTIVE ASSETS PROGRAM
 
    Shares of the  Trusts may  be purchased by  investors maintaining  brokerage
accounts  with Dean Witter  who choose not  to participate in  the Active Assets
program. Shareholders  of the  Trusts  not participating  in the  Active  Assets
program  will not  be charged  a program fee.  The minimum  initial purchase for
non-participants is  $5,000  and  the minimum  subsequent  purchase  is  $1,000.
Non-participants  in the  Active Assets program  who are  participating in other
brokerage account programs with  Dean Witter may  have different initial  and/or
subsequent purchase minimum accounts, and may make share purchases automatically
through their account programs. Dean Witter account holders should contact their
account executive for further information concerning methods of purchase.
 
    The  Trusts have been created for the  purpose of serving as investments for
participants in the  Active Assets program  and, as such,  do not in  themselves
offer  such typical  money market  fund features  as check  writing and exchange
privileges. There  are other  money  market funds,  including funds  managed  by
InterCapital,  which have investment objectives similar  to the Trusts and which
offer check writing and  exchange privileges. Prior to  making an investment  in
any such money market fund, an investor should obtain and read the prospectus.
 
                                      A-2
<PAGE>
REDEMPTION OF SHARES
 
    Each  Trust is required to redeem for cash all full and fractional shares of
the Trust. The redemption price is the net asset value per share next determined
after  receipt  by  Dean  Witter   Trust  Company  (the  "Transfer  Agent")   of
instructions  from Dean  Witter in accordance  with the  automatic procedure set
forth below  (non-participants in  the Active  Assets program  see below).  Such
instructions  are delivered to the Transfer  Agent prior to the determination of
net asset value at 12 noon,  New York time, on any  day that the New York  Stock
Exchange  is  open for  business,  or on  each  other day  in  which there  is a
sufficient degree  of  trading in  the  Trust's portfolio  securities  that  the
current  net asset value of  the Trust's shares might  be materially affected by
changes in the value of such portfolio  securities, but only if on any such  day
the Trust is required by the provisions of the Active Assets program to purchase
or  redeem Trust shares. Payment of the  redemption proceeds will be made on the
same day  the  redemption  becomes effective.  Shareholders  will  receive  upon
redemption all dividends declared and reinvested until the time of redemption.
 
    Redemption  will be automatically  effected by Dean  Witter to satisfy debit
balances in the  Securities Account created  by activity therein  or to  satisfy
debit  balances created by  Visa credit card purchases,  cash advances or checks
written  against  the  Visa  Account.   Each  Active  Assets  account  will   be
automatically  scanned  for debits  each business  day that  the New  York Stock
Exchange is open for business as of the close of business on that day, and after
application of any free credit  cash balances in the  account to such debits,  a
sufficient  number of Trust shares owned  by the Active Assets participants will
be redeemed  at 12  noon the  following business  day to  satisfy any  remaining
debits  in either the Securities Account or  the Visa Account. Margin loans will
be utilized  to satisfy  debits remaining  after the  liquidation of  all  Trust
shares in an Active Assets participant's account and shares may not be purchased
until all debits and margin loans in the account are satisfied. Dean Witter (not
the  Trusts) may impose a fee for the use of the Visa credit card to obtain cash
advances.
 
    The right to receive payment with respect to any redemption may be suspended
by each Trust for a period of up  to seven days. Suspensions of more than  seven
days  may not be  made except (1) for  any period (a) during  which the New York
Stock Exchange is closed  other than customary weekend  and holiday closings  or
(b)  during which trading on the New  York Stock Exchange is restricted; (2) for
any period during which an emergency exists as a result of which (a) disposal by
the Trust of securities owned by it  is not reasonably practicable or (b) it  is
not  reasonably practicable for the  Trust to fairly determine  the value of its
net assets;  or  (3) for  such  other periods  as  the Securities  and  Exchange
Commission  may by order  permit for the  protection of security  holders of the
Trust. The Commission shall  by rules and  regulations determine the  conditions
under  which (i) trading shall be deemed  to be restricted and (ii) an emergency
shall be deemed  to exist within  the meaning  of clause (2)  above. At  various
times  the Trusts may be  requested to redeem shares  with respect to which good
payment has not  yet been received  by the  Distributor. A Trust  may delay,  or
cause  to be delayed, the payment of  the redemption proceeds until such time as
it has assured itself that good payment  has been collected for the purchase  of
such shares. In addition, where the shares to be redeemed have been purchased by
check  (including a  certified or  bank cashier's  check), automatic  and manual
redemptions may be delayed for the minimum time needed to verify that the  check
used  for investment has been honored (not  more than fifteen days from the time
of receipt of the check).
 
    The total value  of a shareholder's  investment in  a Trust at  the time  of
redemption  may be more or less than his  or her cost, depending on the value of
the securities held by the Trust at such time and income earned.
 
    If a participant wishes to reduce or eliminate his or her investment in  the
Trust shares component of the Active Assets program, he or she should first call
the  Active  Assets information  number shown  on the  cover page  preceding the
Active Assets Money  Trust Prospectus, to  ascertain the balance  in his or  her
Trust  Account. He  or she  may then withdraw  an amount  equal to  the value of
 
                                      A-3
<PAGE>
such shares, less any charges  pending in his or  her Active Assets account,  in
any of the following ways:
 
    (a) by writing a check against the Visa Account in such amount;
 
    (b)  by obtaining a  cash advance from  a Visa participating  bank or branch
        thereof for such amount (which the bank may limit to $5,000 per  account
        per day); or
 
    (c)  by calling his  or her Dean  Witter Account Executive  and requesting a
        cash disbursement from the Active Assets program for such amount.
 
    In any of the above methods, the Trust share balance at any time is  subject
to reduction due to prior debits against the participant's account. Accordingly,
if  payment is  requested through  the Visa  Account check  or the  cash advance
methods and if any other debits are paid by automatic redemption of Trust shares
prior to the time  the check or  cash advance charge  is presented for  payment,
then  the Trust share  balance will be reduced.  If so, payment  of the check or
cash advance may be paid  in part from the margin  loan value of the  Securities
Account or may result in an overdraft. In addition, Dean Witter (not the Trusts)
may impose a fee for the checkwriting service on certain Active Assets accounts.
 
    Under  the Active  Assets program,  both Dean Witter  and Bank  One have the
right to terminate an Active Assets account  for any reason. In such event,  all
shares held in a shareholder's account will be redeemed.
 
REDEMPTION OF SHARES BY NON-PARTICIPANTS IN ACTIVE ASSETS PROGRAM
 
    Shareholders  who are not participating in  the Active Assets program should
contact Dean Witter, through his  or her account executive,  on any day the  New
York  Stock Exchange is open, to effect a redemption of shares of the Trust. All
such redemption  requests will  be  promptly forwarded  to the  Transfer  Agent;
redemption  requests should not be  sent directly to the  Trusts or the Transfer
Agent. If such requests are inadvertently  sent to the Trust or Transfer  Agent,
they  will  be  forwarded to  the  Distributor.  Cash proceeds  from  the manual
redemption of Trust shares ordinarily will be credited to the shareholder's Dean
Witter brokerage account or,  on request, will be  mailed to the shareholder  at
his or her address of record. In certain instances, as where redemption requests
are  received in writing, such redemption  requests will require written notices
containing  the  signatures  of  all  persons  in  whose  name  the  shares  are
registered,  or  additional  documents  such  as,  but  not  limited  to,  trust
instruments, death certificates, appointments  as executor or administrator,  or
certificates  of  corporate  authority. Non-participants  in  the  Active Assets
program who  are participating  in other  brokerage account  programs with  Dean
Witter  may effect redemption of shares  automatically, as provided for in their
account program.  Dean  Witter  account holders  should  contact  their  account
executive for further information concerning methods of redemption.
 
HOW NET ASSET VALUE IS DETERMINED
 
    The  net asset value per share of each Trust, for the purpose of calculating
the price  at  which  shares are  issued  and  redeemed, is  determined  by  the
Investment  Manager as of  12 noon New York  time on each day  that the New York
Stock Exchange is open for business, immediately after the daily declaration  of
dividends.  Each Trust will also calculate such price on each other day in which
there is a sufficient  degree of trading in  that Trust's portfolio  securities,
such  that the current net asset value of the Trust's shares might be materially
affected by changes in the  value of such portfolio  securities, but only if  on
any  such  day the  Trust is  required by  the provisions  of the  Active Assets
program to  purchase  or  redeem Trust  shares  or  receives a  request  from  a
non-participant in the Active Assets program to purchase or redeem Trust shares.
The  determination of net asset  value is made by  subtracting from the value of
the assets of a Trust the amount of its liabilities, and dividing the  remainder
by the number of outstanding shares of the Trust.
 
    The  Trusts utilize  the amortized  cost method  in valuing  their portfolio
securities, even though  the portfolio  securities may increase  or decrease  in
market  value, generally, in regards to changes in interest rates. The amortized
cost method of
valua-
 
                                      A-4
<PAGE>
tion involves valuing a security at its cost adjusted by a constant amortization
to maturity of any original issue discount or premium, regardless of the  impact
of fluctuating interest rates on the market value of the instrument. The purpose
of this method of calculation is to facilitate the maintenance of a constant net
asset  value per share of  $1.00, although there is  no assurance that the $1.00
net asset value will be maintained.
 
CONFIRMATIONS
 
    All purchases and  redemptions of  Trust shares  and dividend  reinvestments
will  be confirmed monthly to the shareholder  (rounded to the nearest share) in
the Active Assets Account Statement. Dean Witter has received an exemptive order
from the Securities and Exchange Commission which permits it to omit sending out
more frequent confirmations with respect to purchases and redemptions.
 
    In the interest  of economy  and convenience  and because  of the  operating
procedures  of the Trusts, certificates representing the Trusts' shares will not
be physically  issued. Shares  are  maintained by  the  Trusts on  the  register
maintained  by the  Transfer Agent  and the holders  thereof will  have the same
rights of ownership  with respect  to such shares  as if  certificates had  been
issued.
 
THE TRUSTS AND THEIR MANAGEMENT
- --------------------------------------------------------------------------------
 
    Money  Trust,  Tax-Free  Trust,  California  Tax-Free  Trust  and Government
Securities Trust  are all  no-load, open-end  diversified investment  management
companies.  Money  Trust, Tax-Free  Trust and  Government Securities  Trust were
organized under the laws of the Commonwealth of Massachusetts as business trusts
on March 30, 1981. California Tax-Free Trust was organized under the laws of the
Commonwealth of Massachusetts as a business trust on July 10, 1991.
 
    InterCapital, located at Two World Trade  Center, New York, New York  10048,
is   the  Trusts'  Investment   Manager.  The  Investment   Manager,  which  was
incorporated in July, 1992,  is a wholly-owned subsidiary  of Dean Witter.  Dean
Witter  is a wholly-owned subsidiary of Dean  Witter, Discover & Co. ("DWDC"), a
balanced financial services organization providing  a broad range of  nationally
marketed credit and investment products.
 
   
    InterCapital  and its wholly-owned subsidiary,  Dean Witter Services Company
Inc.,  serve  in  various   investment  management,  advisory,  management   and
administrative capacities to ninety-eight investment companies (the "Dean Witter
Funds"),  thirty  of which  are  listed on  the  New York  Stock  Exchange, with
combined assets of approximately $81.8 billion at June 30, 1996. The  Investment
Manager  also  manages  portfolios  of  pension  plans,  other  institutions and
individuals which aggregated approximately $2.8 billion at such date.
    
 
    The Trusts have  retained the Investment  Manager to provide  administrative
services,  manage its business  affairs and manage the  investment of the Fund's
assets, including the placing of orders  for the purchase and sale of  portfolio
securities.  InterCapital  has retained  Dean  Witter Services  Company  Inc. to
perform the aforementioned administrative services for the Fund.
 
    The Trusts' Trustees review the various services provided by the  Investment
Manager  to ensure that the Trusts' general investment policies and programs are
being properly carried out and  that administrative services are being  provided
to the Trusts in a satisfactory manner.
 
                                      A-5
<PAGE>
   
    As full compensation for the services and facilities furnished to the Trusts
and expenses of the Trusts assumed by the Investment Manager, the Trusts pay the
Investment   Manager  monthly  compensation  calculated   daily  by  applying  a
percentage rate to the daily net assets  of each of the respective Trusts  which
declines  as net assets of the Trusts reach specified levels (up to $3 billion).
For the fiscal years ended June 30, 1996, the Trusts accrued total  compensation
to  the Investment  Manager amounting  to 0.30%  (Money Trust),  0.41% (Tax-Free
Trust), 0.50%  (California  Tax-Free  Trust) and  0.49%  (Government  Securities
Trust)  of the respective Trusts' average daily net assets and the Trusts' total
expenses  amounted  to  0.47%  (Money  Trust),  0.55%  (Tax-Free  Trust),  0.67%
(California  Tax-Free  Trust) and  0.65%  (Government Securities  Trust)  of the
respective Trusts' average daily net assets.
    
 
PLAN OF DISTRIBUTION
 
   
    Each Trust has adopted a Plan  of Distribution pursuant to Rule 12b-1  under
the  Act. Under the respective Plans, the Distributor has expanded the nature of
its promotional activities on behalf of the respective Trusts and uses its  best
efforts to foster additional sales of Trust shares. The respective Plans provide
that  the  Distributor  bear the  expense  of all  promotional  and distribution
related activities on behalf of the respective Trusts, except for expenses  that
the  respective  Trustees  determine  to  reimburse,  as  described  below.  The
following activities and services may be  provided by the Distributor under  the
respective  Plans: (1) compensation to sales  representatives of Dean Witter and
other broker-dealers; (2) sales incentives and bonuses to sales  representatives
and  to marketing personnel in connection with  promoting sales of shares of the
Trusts; (3) expenses incurred  in connection with promoting  sales of shares  of
the  Trusts; (4) preparing and distributing  sales literature; and (5) providing
advertising and promotional activities,  including direct mail solicitation  and
television,   radio,  newspaper,   magazine  and   other  media  advertisements.
Reimbursements for these services are made in monthly payments by each Trust  at
the  annual rate of  up to 0.15  of 1% of  the average daily  net assets of each
Trust. Such  payments  were made  by  Money Trust,  Tax-Free  Trust,  California
Tax-Free  Trust and Government Securities Trust at the annual rate of 0.10 of 1%
of each Trust's average daily net assets for their respective fiscal years ended
June 30,  1996. Dean  Witter  account executives  are  paid an  annual  residual
commission,  currently a gross residual of up to 0.10 of 1% of the current value
of the respective accounts of which they are the account executive of record. In
addition, some  Dean  Witter  sales  personnel will  receive  various  types  of
non-cash  compensation as special sales incentives, including trips, educational
and/ or business seminars and merchandise. Expenses incurred by the  Distributor
pursuant  to the Plans  in any fiscal year  will not be  reimbursed by any Trust
through payments accrued in any subsequent fiscal year.
    
 
    Each Trust's  expenses  include:  the Investment  Management  fee;  the  fee
pursuant  to the  Plan of Distribution  (see "Purchase of  Fund Shares"); taxes;
certain legal, transfer  agent, custodian  and auditing fees;  and printing  and
other  expenses  relating  to the  Trust's  operations which  are  not expressly
assumed by the Investment Manager under its Investment Management Agreement with
each Trust.
 
DIVIDENDS, DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------
 
DIVIDENDS AND DISTRIBUTIONS
 
    Each Trust  declares dividends,  payable  on each  day  the New  York  Stock
Exchange  is open for business, of all  of its daily net investment income (and,
with respect  to Money  Trust and  Government Securities  Trust, net  short-term
capital  gains, if any) to shareholders of record as of 12 noon New York time of
the preceding  business  day. With  respect  to Tax-Free  Trust  and  California
Tax-Free  Trust, dividends  from net short-term  capital gains, if  any, will be
paid periodically. The amount of dividend may fluctuate from day to day and  may
be
 
                                      A-6
<PAGE>
omitted  on some days  if net realized  losses on portfolio  securities exceed a
Trust's net investment income. Dividends  are automatically reinvested daily  in
additional  full and  fractional shares of  a Trust  at the net  asset value per
share determined at 12 noon, New York time on that day.
 
    Each Trust intends to distribute dividends from net long-term capital gains,
if any, at least once each year. A Trust may, however, elect to retain all or  a
portion of any net long-term capital gains in any year for reinvestment.
 
    Dean  Witter will send to  each shareholder a monthly  summary of his or her
account, including information as  to dividends reinvested,  on the Dean  Witter
Transaction Statement.
 
TAXES
 
    Because  the  Trusts  currently  intend  to  distribute  all  of  their  net
investment income and net capital gains,  if any, to shareholders and intend  to
otherwise comply with all the provisions of Subchapter M of the Internal Revenue
Code,  as amended (the "Code"), to qualify as regulated investment companies, it
is not expected that the Trust will be required to pay any federal income tax.
 
    To avoid  being  subject  to  a  31%  federal  withholding  tax  on  taxable
dividends,   capital   gains   distributions   and   proceeds   of  redemptions,
shareholders' taxpayer identification numbers must be furnished and certified as
to accuracy.
 
    MONEY TRUST AND GOVERNMENT SECURITIES TRUST. Distributions of net investment
income and realized net short-term capital gains are taxable to shareholders  as
ordinary  income, whether such distributions are  taken in cash or reinvested in
additional shares. Distributions of long-term capital gains, if any, are taxable
as long-term capital gains,  regardless of how long  the shareholder has held  a
Trust's  shares. No portion of such  dividends or distributions will be eligible
for the federal dividends received deduction for corporations. The Trusts advise
their shareholders annually as to the federal income tax status of distributions
paid during each calendar year.
 
    TAX-FREE TRUST AND CALIFORNIA TAX-FREE  TRUST. The Trusts intend to  qualify
to  pay "exempt-interest dividends"  to their shareholders  by maintaining as of
the close of each quarter  of their taxable year, at  least 50% of the value  of
their  total  assets  in  tax-exempt  securities.  If  a  Trust  satisfies  such
requirement, dividends from net investment income to shareholders, whether taken
in cash or reinvested in additional Trust shares, will be excludable from  gross
income  for federal  income tax  purposes to the  extent net  interest income is
represented by interest on tax-exempt securities. Exempt-interest dividends  are
included,  however, in  determining what portion,  if any, of  a person's Social
Security benefits are subject to federal income tax.
 
    The Code  now subjects  interest received  on certain  otherwise  tax-exempt
securities  to an alternative minimum tax.  This alternative minimum tax applies
to interest received on "private activity bonds" (in general, bonds that benefit
non-government entities) issued after August 7, 1986 which, although  tax-exempt
are used for purposes other than those generally performed by governmental units
(e.g.,  bonds used for commercial or  housing purposes). Income received on such
bonds is classified as  a "tax preference item",  under the alternative  minimum
tax,  for  both  individual and  corporate  investors.  A portion  of  a Trust's
investments may be made in such "private activity bonds," with the result that a
portion of the exempt-interest dividends paid by a Trust will be an item of  tax
preference  to shareholders subject to the alternative minimum tax. In addition,
certain corporations which are subject to  the alternative minimum tax may  have
to   include  a  portion  of  exempt-interest  dividends  in  calculating  their
alternative minimum taxable  income in  situations where  the "adjusted  current
earnings"  of  the  corporation exceeds  its  preadjustment  alternative minimum
taxable income.
 
    Under California law, an investment  company which qualifies as a  regulated
investment company
 
                                      A-7
<PAGE>
must  have at least 50% of the value  of its total assets invested in California
state and local issues or in obligations  of the United States which if held  by
an  individual, would pay  interest excludable from income  (or in a combination
thereof), at the end of each quarter of its taxable year in order to be eligible
to pay  dividends which  will be  exempt from  California personal  income  tax.
Shareholders  of California Tax-Free Trust who are California residents will not
incur any federal  or California  income tax  on the  amount of  exempt-interest
dividends  received by them from the Trust and derived from California state and
local issues or certain United States issues whether taken in cash or reinvested
in additional  shares  to  the  extent that  such  dividends  are  derived  from
California securities.
 
    Within  60 days after  the end of its  fiscal year, the  Trusts will mail to
shareholders statements indicating the percentage of the dividend  distributions
for  such  fiscal  year  which  constitutes  exempt-interest  dividends  and the
percentage, if any, that is taxable, and the percentage, if any, of the  exempt-
interest  dividends which constitutes an item of tax preference. This percentage
should be applied uniformly to any distributions made during the fiscal year  to
determine  the proportion  of dividends that  is tax-exempt.  The percentage may
differ  from  the  percentage  of  tax-exempt  dividend  distributions  for  any
particular month.
 
    Unlike  federal  law,  no  portion  of  the  exempt-interest  dividends will
constitute an  item  of  tax  preference  for  California  personal  income  tax
purposes. Moreover, unlike federal law, an individual's Social Security benefits
are  not  subject to  California personal  income  tax, so  that the  receipt of
California exempt-interest dividends (from  the California Tax-Free Trust)  will
have no effect on an individual's California personal income tax.
 
    Shareholders  will normally  be subject  to federal  and California personal
income  tax  on  dividends  paid  from  interest  income  derived  from  taxable
securities and on distributions of net capital gains, if any. For federal income
tax  purposes, distributions of long-term capital  gains, if any, are taxable to
shareholders as long-term capital  gains, regardless of  how long a  shareholder
has held a Trust's shares and regardless of whether the distribution is received
in  additional shares or  cash. In addition, for  California personal income tax
purposes, the shareholders of the California Tax-Free Trust will not be  subject
to  tax, or receive a credit for tax paid by the Trust, on undistributed capital
gains, if any.  With respect to  the Tax-Free Trust,  the exemption of  interest
income  for federal income tax purposes does not necessarily result in exemption
under the income or other tax laws of any state or local taxing authority. Thus,
shareholders  of  the  Trust  may  be  subject  to  state  and  local  taxes  on
exempt-interest dividends.
 
    Distributions  from investment  income and long-term  and short-term capital
gains will not  be excluded from  taxable income in  determining the  California
corporate income or franchise tax for corporate shareholders. Such distributions
also  may be  includable in  income subject to  the alternative  minimum tax. In
addition, distributions  from investment  income  and long-term  and  short-term
capital  gains may be subject to state taxes in states other than California and
to local taxes.
 
    Interest on  indebtedness incurred  by shareholders  or related  parties  to
purchase  or  carry  shares  of  an  investment  company  paying exempt-interest
dividends, such as the Trust, generally  will not be deductible by the  investor
for federal or California personal income tax purposes.
 
    The  foregoing relates to federal income taxation and to California personal
income taxation as in  effect as of the  date of this Prospectus.  Distributions
from  investment income and capital  gains, including exempt-interest dividends,
may be subject to California franchise taxes if received by a corporation  doing
business  in California, to state  taxes in states other  than California and to
local taxes.
 
                                      A-8
<PAGE>
    Shareholders should consult their  tax advisers as  to the applicability  of
the above to their own tax situation.
 
CURRENT AND EFFECTIVE YIELD
 
    From  time to time the Trusts advertise their "yield" and "effective yield."
Both yield figures  are based  on historical earnings  and are  not intended  to
indicate  future  performance.  The "yield"  of  a  Trust refers  to  the income
generated by an  investment in the  Trust over a  given seven-day period  (which
period  will be stated in the  advertisement). This income is then "annualized."
That is, the amount of income generated by the investment during that  seven-day
period  is assumed to be generated each seven-day period within a 365-day period
and is shown  as a percentage  of the  investment. The "effective  yield" for  a
seven-day period is calculated similarly but, when annualized, the income earned
by  an investment  in a  Trust is assumed  to be  reinvested each  week within a
365-day period. The "effective yield" will  be slightly higher than the  "yield"
because  of the  compounding effect of  this assumed  reinvestment. The Tax-Free
Trust and California Tax-Free Trust  may also quote tax-equivalent yield,  which
is  calculated by determining  the pre-tax yield  which, after being  taxed at a
stated rate, would be equivalent to the yield determined as described above.
 
GENERAL INFORMATION
- --------------------------------------------------------------------------------
 
VOTING RIGHTS
 
    All shares of beneficial interest of a Trust are of $0.01 par value and  are
equal  as to  earnings, assets and  voting privileges. There  are no conversion,
pre-emptive or  other subscription  rights. In  the event  of liquidation,  each
share of beneficial interest of a Trust is entitled to its portion of all of the
Trust's  assets after all debts  and expenses have been  paid. The shares do not
have cumulative voting rights.
 
    In accordance with  each Trust's  Declaration of  Trust, the  Trustees of  a
Trust  will be elected  by a majority  shareholder vote at  the first meeting of
shareholders held following the  initial offering of the  shares of that  Trust.
The  Trustees  will be  elected  for unlimited  terms  at the  first  meeting of
shareholders. The Trustees themselves have the power to alter the number and the
terms of office of the Trustees (as  provided for in the Declaration of  Trust),
and they may at any time lengthen or shorten their own terms or make their terms
of  unlimited duration and appoint their own successors, provided that always at
least a majority of the  Trustees has been elected  by the shareholders of  each
Trust.  Under certain circumstances the Trustees may be removed by action of the
Trustees. The shareholders also  have the right  under certain circumstances  to
remove  the Trustees. The  voting rights of shareholders  are not cumulative, so
that holders of more than 50 percent  of the shares voting can, if they  choose,
elect  all Trustees  being elected,  while the  holders of  the remaining shares
would be unable to elect any Trustees. The Trust is not required to hold  Annual
Meetings of Shareholders and in ordinary circumstances the Trust does not intend
to  hold such meetings.  The Trustees may call  Special Meetings of Shareholders
for action by shareholder vote as may be required by the Act or the  Declaration
of Trust.
 
    The  Declaration of Trust permits the  Trustees to authorize the creation of
additional series  of  shares  (the  proceeds of  which  would  be  invested  in
separate,  independently managed  portfolios) and  additional classes  of shares
within any  series (which  would be  used  to distinguish  among the  rights  of
different categories of shareholders, as might be required by future regulations
or  other unforeseen circumstances).  However, the Trustees  have not authorized
any such additional series  or classes of  shares and the  Trust has no  present
intention  to  add additional  series or  classes of  shares. Trustees  may call
Special Meetings  of Shareholders  for  action by  shareholder  vote as  may  be
required by the Act or the Declaration of Trust.
 
                                      A-9
<PAGE>
    Under Massachusetts law, shareholders of a business trust may, under certain
circumstances,  be held personally  liable as partners for  the obligations of a
Trust. The Declaration of  Trust contains an  express disclaimer of  shareholder
liability  for acts or obligations  of a Trust and  requires that notice of such
disclaimer be given in each instrument entered into or executed by a Trust.  The
Declaration  of Trust provides  for indemnification out  of the Trust's property
for any shareholder  held personally liable  for the obligations  of the  Trust.
Thus,  the  risk  of  a  shareholder  incurring  financial  loss  on  account of
shareholder liability  is limited  to circumstances  in which  the Trust  itself
would  be unable to meet its obligations. Given the nature of the Trusts' assets
and operations, the possibility of a Trust being unable to meet its  obligations
is  remote and, in the opinion of  Massachusetts counsel to the Trusts, the risk
to Trust shareholders is remote.
 
CUSTODIAN
 
    The Bank of New York, 90 Washington Street, New York, New York 10286 is  the
Custodian  of the  Trusts' assets.  The Custodian  has no  part in  deciding the
Trusts' investment policies or which securities are to be purchased or sold  for
the  Trusts' portfolios. Any of the Trust's  cash balances with the Custodian in
excess of $100,000 are unprotected  by Federal deposit insurance. Such  balances
may, at times, be substantial.
 
    CODE  OF ETHICS.   Directors, officers  and employees  of InterCapital, Dean
Witter Services Company Inc. and the Distributor are subject to a strict Code of
Ethics adopted by those companies. The Code of Ethics is intended to ensure that
the interests of shareholders and other clients are placed ahead of any personal
interest, that no undue personal benefit is obtained from a person's  employment
activities  and that actual and potential  conflicts of interest are avoided. To
achieve these goals and comply with regulatory requirements, the Code of  Ethics
requires, among other things, that personal securities transactions by employees
of  the companies be subject to an  advance clearance process to monitor that no
Dean Witter Fund is engaged at the same  time in a purchase or sale of the  same
security.  The Code  of Ethics  bans the  purchase of  securities in  an initial
public offering, and also prohibits engaging in futures and option  transactions
and  profiting on short-term trading (that is, a purchase within sixty days of a
sale or a  sale within sixty  days of a  purchase) of a  security. In  addition,
investment  personnel may  not purchase  or sell  a security  for their personal
account within thirty days  before or after any  transaction in any Dean  Witter
Fund  managed  by them.  Any violations  of the  Code of  Ethics are  subject to
sanctions,  including  reprimand,  demotion  or  suspension  or  termination  of
employment.  The Code  of Ethics comports  with regulatory  requirements and the
recommendations in  the  recent  report  by  the  Investment  Company  Institute
Advisory Group on Personal Investing.
 
    SHAREHOLDER  INQUIRIES.    All  inquiries  regarding  the  Trusts  should be
directed to the Trusts at  the telephone number or at  the address set forth  on
the front cover of these Prospectuses.
 
                                      A-10
<PAGE>
CUSTODIAN
THE BANK OF NEW YORK
90 WASHINGTON STREET
NEW YORK, NEW YORK 10286
TRANSFER AGENT AND
DIVIDEND DISBURSING AGENT
DEAN WITTER TRUST COMPANY
HARBORSIDE FINANCIAL CENTER
PLAZA TWO
JERSEY CITY, NEW JERSEY 07311
INDEPENDENT ACCOUNTANTS
PRICE WATERHOUSE LLP
1177 AVENUE OF THE AMERICAS
NEW YORK, NEW YORK 10036
INVESTMENT MANAGER
DEAN WITTER INTERCAPITAL INC.
 
NO DEALER, SALESMAN OR ANY OTHER PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS, OTHER THAN THOSE CONTAINED IN THESE
PROSPECTUSES OR IN THE STATEMENTS OF ADDITIONAL INFORMATION, IN CONNECTION WITH
THE OFFER CONTAINED IN THESE PROSPECTUSES OR IN THE STATEMENTS OF ADDITIONAL
INFORMATION AND, IF GIVEN OR MADE, SUCH OTHER INFORMATION OR REPRESENTATIONS
MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED BY THE TRUSTS OR THE
DISTRIBUTOR. THESE PROSPECTUSES AND THE STATEMENTS OF ADDITIONAL INFORMATION DO
NOT CONSTITUTE AN OFFER BY THE TRUSTS OR BY THE DISTRIBUTOR TO SELL OR A
SOLICITATION OF ANY OFFER TO BUY ANY OF THE SECURITIES OFFERED HEREBY IN ANY
JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL FOR THE TRUSTS OR THE
DISTRIBUTOR TO MAKE SUCH OFFER IN SUCH JURISDICTION.
 
      [LOGO]
 
ACTIVE ASSETS
MONEY TRUST
ACTIVE ASSETS
TAX-FREE TRUST
ACTIVE ASSETS
CALIFORNIA TAX-FREE
TRUST
ACTIVE ASSETS
GOVERNMENT
SECURITIES TRUST
 
   
PROSPECTUSES
AUGUST 22, 1996
    
 
THE ENCLOSED PROSPECTUSES DESCRIBE FOUR FULLY MANAGED MONEY MARKET TRUSTS.
SHARES OF THE TRUSTS ARE OFFERED DIRECTLY TO CLIENTS OF DEAN WITTER AND TO
PARTICIPANTS IN THE ACTIVE ASSETS-REGISTERED TRADEMARK- ACCOUNT PROGRAM OF DEAN
WITTER REYNOLDS INC.
 
INVESTORS SHOULD BE AWARE THAT THE ACTIVE ASSETS ACCOUNT SERVICE IS NOT A BANK
ACCOUNT. AS WITH ANY INVESTMENT IN SECURITIES, THE VALUE OF A SHAREHOLDER'S
 
INVESTMENT IN THE TRUSTS MAY FLUCTUATE.
 
PRINCIPAL OFFICE OF THE TRUSTS
TWO WORLD TRADE CENTER
NEW YORK, NEW YORK 10048
                                                             [LOGO]
<PAGE>
   
STATEMENTS OF ADDITIONAL INFORMATION
AUGUST 22, 1996                                                           [LOGO]
    
 
- --------------------------------------------------------------------------------
 
    Active  Assets Money Trust (the "Money Trust"  or the "Trust") is a no-load,
diversified open-end management investment  company whose investment  objectives
are  high current income, preservation of capital and liquidity. The Money Trust
seeks to  achieve its  objectives by  investing in  a diversified  portfolio  of
short-term money market instruments.
 
    Active  Assets Tax-Free  Trust (the  "Tax-Free Trust"  or the  "Trust") is a
no-load, diversified  open-end management  investment company  whose  investment
objective  is to  provide as high  a level  of daily income  exempt from federal
personal income tax as is consistent with stability of principal and  liquidity.
The Tax-Free Trust seeks to achieve its objective by investing primarily in high
quality tax-exempt securities with short-term maturities.
 
    Active  Assets California Tax-Free Trust (the "California Tax-Free Trust" or
the "Trust") is  a no-load, diversified  open-end management investment  company
whose  investment objective is to provide as high a level of daily income exempt
from federal and California personal income tax as is consistent with  stability
of  principal and liquidity. The California  Tax-Free Trust seeks to achieve its
objective by  investing primarily  in high  quality tax-exempt  securities  with
short-term maturities.
 
    Active Assets Government Securities Trust (the "Government Securities Trust"
or the "Trust") is a no-load, diversified open-end management investment company
whose investment objectives are high current income, preservation of capital and
liquidity.  The Government  Securities Trust seeks  to achieve  its objective by
investing in U.S. Government securities, including a variety of securities which
are issued  or guaranteed  by  the United  States  Government, its  agencies  or
instrumentalities.
 
   
    Prospectuses  for  the  Money  Trust,  the  Tax-Free  Trust,  the California
Tax-Free Trust and the Government Securities  Trust, all dated August 22,  1996,
which  provide the basic information you should  know before investing in any of
the aforementioned Trusts, may be obtained without charge from any of the Trusts
at the address or telephone number listed below. These Statements of  Additional
Information  are not Prospectuses.  They contain information  in addition to and
more detailed than  that set  forth in the  Prospectuses. They  are intended  to
provide  additional information regarding  the activities and  operations of the
Trusts, and should be read in conjunction with the Prospectuses. They should  be
read  with the information appearing  in the Appendix hereto  which is a part of
these Statements of Additional Information.
    
 
Active Assets Money Trust
Active Assets Tax-Free Trust
Active Assets California Tax-Free Trust
Active Assets Government Securities Trust
Two World Trade Center
New York, New York 10048
(212) 392-2550
 
    The shares of the Money Trust,  the Tax-Free Trust, the California  Tax-Free
Trust  and the  Government Securities Trust  are offered to  participants in the
Active Assets Account program of Dean  Witter Reynolds Inc. ("Dean Witter").  In
addition,  shares of the  Trusts are offered  to investors maintaining brokerage
accounts with Dean Witter who are not subscribers to the Active Assets  program.
For  further information,  either consult  the Dean  Witter Client  Agreement or
consult your Dean Witter Account Executive.
 
Active Assets Money Trust
<PAGE>
ACTIVE ASSETS MONEY TRUST
TABLE OF CONTENTS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                                                     <C>
Investment Practices and Policies.....................................      3
 
Investment Restrictions...............................................      4
 
How Net Asset Value is Determined.....................................      5
 
Dividends, Distributions and Taxes....................................      7
 
Financial Statements..................................................      9
 
Report of Independent Accountants.....................................     14
 
APPENDIX
 
Investment Manager....................................................    A-1
 
Trustees and Officers.................................................    A-7
 
Portfolio Transactions and Brokerage..................................   A-15
 
General Information...................................................   A-16
 
Custodian and Transfer Agent..........................................   A-16
 
Independent Accountants...............................................   A-17
 
Reports to Shareholders...............................................   A-17
 
Legal Counsel.........................................................   A-17
 
Experts...............................................................   A-17
 
Registration Statement................................................   A-17
 
Information with Respect to Securities Ratings........................   A-17
</TABLE>
    
 
Active Assets Money Trust                2
<PAGE>
INVESTMENT PRACTICES AND POLICIES
- --------------------------------------------------------------------------------
 
    REPURCHASE AGREEMENTS.   As discussed in  the Prospectus, when  cash may  be
available  for only a  few days, it may  be invested by  the Trust in repurchase
agreements until such time as it may otherwise be invested or used for  payments
of  obligations of the Trust. These agreements, which may be viewed as a type of
secured lending by the Trust, typically involve the acquisition by the Trust  of
debt securities from a selling financial institution such as a bank, savings and
loan  association or broker-dealer.  The agreement provides  that the Trust will
sell back to  the institution,  and that  the institution  will repurchase,  the
underlying security ("collateral"), which is held by the Trust's Custodian, at a
specified  price and at  a fixed time in  the future, which  is usually not more
than seven days from the date of  purchase. The Trust will accrue interest  from
the  institution until the time  when the repurchase is  to occur. Although such
date is deemed by the Trust to  be the maturity date of a repurchase  agreement,
the maturities of securities subject to repurchase agreements are not subject to
any limits and may exceed one year.
 
   
    While repurchase agreements involve certain risks not associated with direct
investments  in  debt  securities,  the  Trust  follows  procedures  designed to
minimize such risks. These procedures include effecting repurchase  transactions
only  with large, well capitalized  and well established financial institutions,
whose financial condition will be continually monitored. In addition, the  value
of  the collateral underlying  the repurchase agreement will  always be at least
equal to the  resale price  which consists  of the  purchase price  paid to  the
seller of the securities plus the accrued resale premium which is defined as the
amount  specified in the  repurchase agreement or the  daily amortization of the
difference between the  purchase price  and the  resale price  specified in  the
repurchase  agreement. Such collateral will  consist entirely of securities that
are direct obligations  of, or  that are fully  guaranteed as  to principal  and
interest  by, the  United States or  any agency thereof,  and/or certificates of
deposit, bankers' acceptances  which are  eligible for acceptance  by a  Federal
Reserve Bank, and, if the seller is a bank, mortgage related securities (as such
term is defined in section 3(a)(41) of the Securities Exchange Act of 1934 that,
at  the time the repurchase agreement is  entered into, are rated in the highest
rating category  by  the Requisite  NRSROs.  Additionally, the  collateral  must
quality  the repurchase agreement  for preferential treatment  under the Federal
Deposit Insurance Act or the Federal Bankruptcy Code. In the event of a  default
or  bankruptcy  by  a selling  financial  institution,  the Trust  will  seek to
liquidate such  collateral.  However,  the  exercise of  the  Trust's  right  to
liquidate  such collateral  could involve  certain costs  or delays  and, to the
extent that  proceeds  from  any  sale  upon a  default  of  the  obligation  to
repurchase  were less than the repurchase price,  the Trust could suffer a loss.
It is the current  policy of the  Trust not to  invest in repurchase  agreements
that  do not mature within seven days  if any such investment, together with any
other illiquid asset held  by the Trust,  amount to more than  10% of its  total
assets.  The  Trust's investments  in repurchase  agreements  may, at  times, be
substantial when, in the  view of the Trust's  investment manager, liquidity  or
other considerations warrant.
    
 
    LENDING  OF  PORTFOLIO SECURITIES.   Subject  to Investment  Restriction (2)
below, the Trust may lend portfolio securities to brokers, dealers and financial
institutions provided  that cash  equal to  at least  100% of  the market  value
(including  accrued  interest)  of the  securities  loaned is  deposited  by the
borrower with the  Trust and  is maintained each  business day  in a  segregated
account  pursuant to applicable regulations. While  such securities are on loan,
the borrower will pay the Trust any  income accruing thereon, and the Trust  may
invest  the cash collateral in  portfolio securities, thereby earning additional
income. The Trust will not lend its  portfolio securities if such loans are  not
permitted  by  the laws  or regulations  of any  state in  which its  shares are
qualified for sale and  will not lend more  than 10% of the  value of its  total
assets.  The creditworthiness  of firms  to which  the Fund  lends its portfolio
securities will be  monitored on  an ongoing basis.  Loans would  be subject  to
termination  by the Trust in the  normal settlement time, currently two business
days after notice, or by the  borrower on one day's notice. Borrowed  securities
must  be returned when  the loan is terminated.  Any gain or  loss in the market
price of the borrowed securities which occurs during the term of the loan inures
to the Trust and its shareholders. The Trust
 
Active Assets Money Trust                3
<PAGE>
   
may pay reasonable  finders, borrowers,  administrative, and  custodial fees  in
connection  with a loan. During  its fiscal year ended  June 30, 1996, the Trust
did not lend any of its portfolio securities and it has no intention of doing so
in the foreseeable future.
    
 
    VARIABLE AND FLOATING RATE  OBLIGATIONS.  As stated  in the Prospectus,  the
Trust  may invest in  variable and floating rate  obligations. The interest rate
payable on  a variable  rate obligation  is adjusted  at predesignated  periodic
intervals  and, on floating rate obligations, whenever  there is a change in the
market rate  of interest  on which  the interest  rate payable  is based.  Other
features  may include the right  whereby the Trust may  demand prepayment of the
principal amount  of the  obligation prior  to its  stated maturity  (a  "demand
feature")  and the right of  the issuer to prepay  the principal amount prior to
maturity. The  principal benefit  of  a variable  rate  obligation is  that  the
interest   rate  adjustment  minimizes  changes  in  the  market  value  of  the
obligation. As  a  result, the  purchase  of  variable rate  and  floating  rate
obligations  should enhance the  ability of the  Trust to maintain  a stable net
asset value per  share (see "How  Net Asset  Value is Determined")  and to  sell
obligations prior to maturity at a price approximating the full principal amount
of the obligations. The principal benefit to the Trust of purchasing obligations
with  a demand feature is that liquidity, and the ability of the Trust to obtain
repayment of the full  principal amount of an  obligation prior to maturity,  is
enhanced.   The  payment  of  principal  and  interest  by  issuers  of  certain
obligations purchased by  the Trust may  be guaranteed by  letters of credit  or
other  credit facilities offered by banks  or other financial institutions. Such
guarantees will be  considered in  determining whether an  obligation meets  the
Trust's investment quality requirements.
                                  ------------
 
    The  Trust will  attempt to balance  its objectives of  high current income,
preservation of  capital and  liquidity by  investing in  securities of  varying
maturities  and risks. The Trust will not, however, invest in securities with an
effective maturity of more than one year from the date of purchase (see "How Net
Asset Value  is Determined").  The amounts  invested in  obligations of  various
maturities  of one year  or less will  depend on management's  evaluation of the
risks involved.  Longer-term  issues,  while generally  paying  higher  interest
rates,  are  subject to  greater fluctuations  in  value resulting  from general
changes in interest rates than shorter-term issues. Thus, when rates on new debt
securities increase, the value of  outstanding securities may decline, and  vice
versa.  Such changes may also occur, to a lesser degree, with short-term issues.
These changes, if  experienced, may cause  fluctuations in the  amount of  daily
dividends  and, in extreme cases,  could cause the net  asset value per share to
decline (see  "How Net  Asset  Value is  Determined"). Longer-term  issues  also
increase  the  risk that  the  issuer may  be unable  to  pay an  installment of
interest or principal at  maturity. In the event  of unusually large  redemption
demands, such securities may have to be sold at a loss prior to maturity, or the
Trust  might have to borrow money and incur interest expenses. Either occurrence
would adversely impact upon the amount of daily dividends and could result in  a
decline  in the daily net asset value per share or the reduction by the Trust of
shares held in a shareholder's account. The Trust will attempt to minimize these
risks by  investing in  relatively  longer-term securities  when it  appears  to
management   that  yields  on  such  securities   are  not  likely  to  increase
substantially during the period of expected holding, and then only in securities
which are readily marketable. However, there can be no assurance that the  Trust
will be successful in achieving this objective.
 
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    In addition to the investment restrictions enumerated in the Prospectus, the
investment  restrictions listed below have  been adopted as fundamental policies
which cannot be changed without the approval  of the holders of a "majority"  of
the  outstanding shares of the Trust as defined in the Investment Company Act of
1940, as amended (the "Act").  Majority is defined in the  Act as the lesser  of
(a)  sixty-seven  percent  or  more  of  the  shares  present  at  a  meeting of
shareholders, if  the holders  of more  than fifty  percent of  the  outstanding
shares  of the Trust are present or represented by proxy, or (b) more than fifty
percent of the outstanding shares of the Trust.
 
Active Assets Money Trust                4
<PAGE>
    These restrictions provide that the Trust may not:
 
         1. Purchase any common stocks or other equity securities;
 
         2. Make  loans to  others,  except through  the  purchase of  the  debt
    obligations   and  repurchase  agreements   referred  to  under  "Investment
    Practices and Policies" above and under "Investment Objectives and Policies"
    in the Prospectus and loans of portfolio securities, not in excess of 10% of
    the value of the Trust's total assets, made in accordance with guidelines of
    the Trustees, including  maintaining collateral from  the borrower equal  at
    all times to the current market value of the securities loaned;
 
         3.  Purchase  or  sell real  estate;  however, the  Trust  may purchase
    marketable securities issued  by companies  which invest in  real estate  or
    interests therein;
 
         4. Purchase securities on margin or sell short;
 
         5. Purchase or sell commodities or commodity futures contracts, or oil,
    gas, or mineral exploration or development programs;
 
         6.  Purchase  securities  for  which  there  are  legal  or contractual
    restrictions on resale (i.e.  restricted securities), except for  repurchase
    agreements;
 
         7. Underwrite securities of other issuers;
 
         8.   Purchase  warrants,  or  write,  purchase  or  sell  puts,  calls,
    straddles, spreads or combinations thereof;
 
         9. Participate on a joint or joint and several basis in any  securities
    trading account;
 
        10.  Purchase the securities of any  other investment company, except in
    connection with a  merger, consolidation, reorganization  or acquisition  of
    assets;
 
        11.  Purchase securities  of any  issuer for  the purpose  of exercising
    control or management; and
 
        12. Invest  in securities  of any  issuer if,  to the  knowledge of  the
    Trust,  any officer, Trustee or  director of the Trust  or of the Investment
    Manager owns  more than  1/2 of  1% of  the outstanding  securities of  such
    issuer and such officers, Trustees and directors who own more than 1/2 of 1%
    own  in the  aggregate more  than 5% of  the outstanding  securities of such
    issuer.
 
    If a percentage restriction is  adhered to at the  time of an investment,  a
later  increase or decrease in  percentage resulting from a  change in values of
portfolio securities or amount of total or  net assets will not be considered  a
violation of any of the foregoing restrictions.
 
HOW NET ASSET VALUE IS DETERMINED
- --------------------------------------------------------------------------------
 
    As  discussed in the Appendix to the  Prospectus, the net asset value of the
Trust is determined as of 12  noon New York time on  each day that the New  York
Stock  Exchange  is open.  The New  York Stock  Exchange currently  observes the
following holidays: New Year's Day; President's Day; Good Friday; Memorial  Day;
Independence Day; Labor Day; Thanksgiving Day; and Christmas Day.
 
    The  Trust  utilizes  the amortized  cost  method in  valuing  its portfolio
securities for purposes of determining the net asset value of the shares of  the
Trust.  The Trust  utilizes the amortized  cost method in  valuing its portfolio
securities even  though the  portfolio securities  may increase  or decrease  in
market  value,  generally, in  connection with  changes  in interest  rates. The
amortized cost  method of  valuation involves  valuing a  security at  its  cost
adjusted  by a  constant amortization  to maturity  of any  discount or premium,
regardless of the impact  of fluctuating interest rates  on the market value  of
the instrument. While this method provides certainty in valuation, it may result
in  periods during which  value, as determined  by amortized cost,  is higher or
lower than the price the Trust would  receive if it sold the instrument.  During
such  periods the yield to investors in  the Trust may differ somewhat from that
 
Active Assets Money Trust                5
<PAGE>
obtained in a  similar company  which uses  mark to  market values  for all  its
portfolio  securities. For example, if  the use of amortized  cost resulted in a
lower (higher)  aggregate portfolio  value on  a particular  day, a  prospective
investor  in the Trust would  be able to obtain  a somewhat higher (lower) yield
than would  result  from investment  in  such  a similar  company  and  existing
investors  would  receive less  (more) investment  income.  The purpose  of this
method of calculation is to facilitate  the maintenance of a constant net  asset
value per share of $1.00.
 
    The  Trust's  use  of  the  amortized cost  method  to  value  its portfolio
securities is permitted pursuant  to Rule 2a-7  of the Act  (the "Rule") and  is
conditioned  on its  compliance with  various conditions  contained in  the Rule
including: (a) the Trustees are obligated, as a particular responsibility within
the overall  duty  of  care  owed to  the  Trust's  shareholders,  to  establish
procedures  reasonably designed,  taking into account  current market conditions
and the Trust's  investment objectives,  to stabilize  the net  asset value  per
share  as computed for the  purpose of distribution and  redemption at $1.00 per
share; (b)(i)  the procedures  include  calculation, at  such intervals  as  the
Trustees  determine are  appropriate and as  are reasonable in  light of current
market conditions, of the  deviation, if any between  net asset value per  share
using amortized cost to value portfolio securities and net asset value per share
based   upon  available  market  quotations   with  respect  to  such  portfolio
securities; (ii) periodic review by the  Trustees of the amount of deviation  as
well  as methods used to calculate it;  and (iii) maintenance of written records
of the procedures, and  the Trustees' considerations made  pursuant to them  and
any  actions taken upon  such consideration; c) the  Trustees will consider what
steps should be taken, if any, in the event of a difference of more than 1/2  of
1%  between the two methods of valuation;  and (d) the Trustees should take such
action as  they  deem appropriate  (such  as shortening  the  average  portfolio
maturity,  realizing  gains or  losses,  withholding dividends  or  reducing the
number of the outstanding  shares of the  Trust) to eliminate  or reduce to  the
extent  reasonably  practicable material  dilution  or other  unfair  results to
investors or existing  shareholders which might  arise from differences  between
the  two  methods of  valuation.  Any reduction  of  outstanding shares  will be
effected by having  each shareholder proportionately  contribute to the  Trust's
capital  the  necessary shares  that represent  the amount  of excess  upon such
determination.  Each  shareholder  will  be  deemed  to  have  agreed  to   such
contribution  in these circumstances by investment in the Trust. See "Dividends,
Distributions and Taxes" for a discussion of the tax effect of such reduction.
 
    Generally, for  purposes  of the  procedures  adopted under  the  Rule,  the
maturity  of  a  portfolio  instrument  is deemed  to  be  the  period remaining
(calculated from the trade date or such other date on which the Trust's interest
in the instrument is subject to market action) until the date noted on the  face
of  the instrument as the date on which the principal amount must be paid, or in
the case  of  an  instrument  called  for redemption,  the  date  on  which  the
redemption payment must be made.
 
    A  variable rate obligation that is subject to a demand feature is deemed to
have a maturity  equal to  the longer  of the  period remaining  until the  next
readjustment  of the interest  rate or the period  remaining until the principal
amount can  be recovered  through demand.  A floating  rate instrument  that  is
subject  to a demand  feature is deemed to  have a maturity  equal to the period
remaining until the principal amount can be recovered through demand.
 
   
    An Eligible Security generally is defined in the Rule to mean (i) A security
with a remaining  maturity of  397 calendar  days or  less that  has received  a
short-term  rating (or  that has been  issued by  an issuer that  has received a
short-term rating  with respect  to a  class of  debt obligations,  or any  debt
obligation  within that class, that is  comparable in priority and security with
the security)  by the  Requisite NRSROs  in one  of the  two highest  short-term
rating  categories  (within  which  there may  be  sub-categories  or gradations
indicating relative  standing); or  (ii) A  security: (A)  That at  the time  of
issuance  had a remaining maturity of more than 397 calendar days but that has a
remaining maturity  of 397  calendar days  or  less; and  (B) Whose  issuer  has
received  from the  Requisite NRSROs a  rating with  respect to a  class of debt
obligations (or any debt obligation within that class) that is now comparable in
priority and security with  the security, in one  of the two highest  short-term
rating categories (within which there may be sub-
    
 
Active Assets Money Trust                6
<PAGE>
   
categories  or  gradations indicating  relative standing);  or (iii)  An Unrated
Security that is of comparable quality to a security meeting the requirements of
(i) or (ii) above, as determined by the money market fund's board of directors.
    
 
    As permitted by the Rule, the Board has delegated to the Trust's  Investment
Manager,  subject to the Board's oversight pursuant to guidelines and procedures
adopted by  the  Board, the  authority  to determine  which  securities  present
minimal  credit risks and which unrated  securities are comparable in quality to
rated securities.
 
    Also, as  required by  the Rule,  the Trust  will limit  its investments  in
securities,  other than Government securities, so that, at the time of purchase:
(a) except as further limited in (b) below with regard to certain securities, no
more than 5% of its total assets will  be invested in the securities of any  one
issuer;  and (b) with respect to Eligible Securities that have received a rating
in less than the  highest category by  any one of the  NRSROs whose ratings  are
used  to qualify the  security as an  Eligible Security, or  determined to be of
comparable quality: (i) no  more than 5%  in the aggregate  of the Trusts  total
assets  in all such securities, and (ii) no more than the greater of 1% of total
assets, or $1 million, in the securities on any one issuer.
 
    The presence of a line of credit or other credit facility offered by a  bank
or  other financial institution  which guarantees the  payment obligation of the
issuer, in the event of a default in the payment of principal or interest of  an
obligation  may be taken into account in determining whether an investment is an
Eligible Security, provided that the guarantee itself is an Eligible Security.
 
    The Rule  further requires  that the  Trust limit  its investments  to  U.S.
dollar-denominated  instruments  which  the Trustees  determine  present minimal
credit risks and which are Eligible Securities. The Rule also requires the Trust
to maintain a dollar-weighted average portfolio maturity (not more than 90 days)
appropriate to its objective  of maintaining a stable  net asset value of  $1.00
per share and precludes the purchase of any instrument with a remaining maturity
of  more than 397 days. Should the disposition of a portfolio security result in
a dollar-weighted average  portfolio maturity of  more than 90  days, the  Trust
will invest its available cash in such a manner as to reduce such maturity to 90
days or less as soon as is reasonably practicable.
 
    If  the Board determines that  it is no longer in  the best interests of the
Trust and its shareholders to maintain a stable price of $1 per share or if  the
Board believes that maintaining such price no longer reflects a market-based net
asset  value per share, the Board has the right to change from an amortized cost
basis of  valuation to  valuation based  on market  quotations. The  Trust  will
notify shareholders of any such change.
 
DIVIDENDS, DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------
 
    As discussed in the Appendix to the Prospectus, the Trust intends to declare
dividends  payable on each day the New  York Stock Exchange is open for business
of all of its daily net investment  income and net short-term capital gains,  if
any,  to shareholders  of record as  of 12 noon  New York time  of the preceding
business day. Net income, for  dividend purposes, includes accrued interest  and
amortization of original issue and market discount, plus or minus any short-term
gains or losses realized on sales of portfolio securities, less the amortization
of  market premium and the  estimated expenses of the  Trust. Net income will be
calculated immediately prior to the determination  of net asset value per  share
of the Trust.
 
    Gains  or losses on the  sales of securities by  the Trust will be long-term
capital gains or losses if the securities  have been held by the Trust for  more
than  twelve months. Gains or  losses on the sale  of securities held for twelve
months or less will be short-term capital gains or losses.
 
    The Trustees may revise the above  dividend policy, or postpone the  payment
of  dividends,  if the  Trust  should have  or  anticipate any  large unexpected
expense, loss  or  fluctuation  in net  assets  which,  in the  opinion  of  the
Trustees,  might have a significant adverse effect on shareholders. On occasion,
in
 
Active Assets Money Trust                7
<PAGE>
order to maintain  a constant $1  per share  net asset value,  the Trustees  may
direct  that the number  of outstanding shares be  reduced in each shareholder's
account. Such reduction may result in taxable income to a shareholder in  excess
of  the net  increase (i.e.,  dividends, less such  reductions), if  any, in the
shareholder's account for a period. Furthermore, such reduction may be  realized
as a capital loss when the shares are liquidated.
 
    The  Trust  has qualified  and intends  to remain  qualified as  a regulated
investment company under Subchapter M of  the Internal Revenue Code of 1986,  as
amended  (the "Code"). If so qualified, the Trust will not be subject to federal
income or  excise taxes  provided that  it distributes  all of  its taxable  net
investment income and all of its net realized capital gains.
 
    Shareholders  will be subject  to federal income tax  on dividends paid from
interest income derived from taxable securities and on distributions of realized
net short-term capital gains. Such interest and realized net short-term  capital
gains  dividends and  distributions are taxable  to the  shareholder as ordinary
dividend  income   regardless  of   whether   the  shareholder   receives   such
distributions  in  additional shares  or in  cash. Since  the Trust's  income is
expected to be derived entirely from interest rather than dividends, none of the
Trust's dividends/distributions  will  be  eligible for  the  federal  dividends
received deduction available to corporations.
 
    The  Code requires each regulated investment  company to pay a nondeductible
4% excise  tax  to the  extent  the company  does  not distribute,  during  each
calendar  year, 98% of its ordinary income, determined on a calendar year basis,
and 98% of its capital gains, determined  in general on an October 31 year  end,
plus  certain undistributed amounts  from previous years.  The Trust anticipates
that it will  make sufficient timely  distributions to avoid  imposition of  the
excise tax.
 
    Under   present  Massachusetts  law,  the  Trust   is  not  subject  to  any
Massachusetts income tax during any fiscal year in which the Trust qualifies  as
a  regulated investment  company. The  Trust might  be subject  to Massachusetts
income taxes for any taxable year in which it does not so qualify as a regulated
investment company.
 
    The Trust may be  subject to tax  or taxes in certain  states where it  does
business.  Furthermore,  in those  states which  have income  tax laws,  the tax
treatment of the Trust and of shareholders with respect to distributions by  the
Trust may differ from Federal tax treatment.
 
    Shareholders  are urged to consult their own tax advisers regarding specific
questions as to Federal, state or local taxes.
 
INFORMATION ON COMPUTATION OF YIELD
 
    The Trust's annualized current yield, as may be quoted from time to time  in
advertisements and other communications to shareholders and potential investors,
is  computed  by determining,  for a  stated seven-day  period, the  net change,
exclusive of  capital  changes and  including  the value  of  additional  shares
purchased  with dividends  and any  dividends declared  therefrom (which reflect
deductions of all expenses of the Trust  such as management fees), in the  value
of  a hypothetical  pre-existing account  having a balance  of one  share at the
beginning of the period, and dividing the difference by the value of the account
at the beginning of the base period  to obtain the base period return, and  then
multiplying the base period return by (365/7).
 
    The  Trust's annualized effective yield, as may  be quoted from time to time
in  advertisements  and  other  communications  to  shareholders  and  potential
investors,  is computed by determining (for  the same stated seven-day period as
for the  current  yield), the  net  change,  exclusive of  capital  changes  and
including  the  value  of additional  shares  purchased with  dividends  and any
dividends declared therefrom (which  reflect deductions of  all expenses of  the
Trust  such as  management fees),  in the  value of  a hypothetical pre-existing
account having  a balance  of one  share at  the beginning  of the  period,  and
dividing the difference by the value of the account at the beginning of the base
period  to obtain the base  period return, and then  compounding the base period
return by adding 1, raising the  sum to a power equal  to 365 divided by 7,  and
subtracting 1 from the result.
 
Active Assets Money Trust                8
<PAGE>
    The  yields quoted in any advertisement or other communication should not be
considered a representation of the yields of  the Trust in the future since  the
yield  is not fixed. Actual yields will depend not only on the type, quality and
maturities of the investments held by the Trust and changes in interest rates on
such investments, but also on changes in the Trust's expenses during the period.
 
    Yield information may be  useful in reviewing the  performance of the  Trust
and  for providing  a basis for  comparison with  other investment alternatives.
However, unlike bank deposits or other  investments which typically pay a  fixed
yield for a stated period of time, the Trust's yield fluctuates.
 
   
    The Trust's current yield for the seven days ending June 30, 1996 was 4.91%.
The effective annual yield on 4.91% is 5.03%, assuming daily compounding.
    
 
Active Assets Money Trust                9
<PAGE>
ACTIVE ASSETS MONEY TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
 
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                          <C>
ASSETS:
Investments in securities, at value
  (amortized cost $7,160,110,336)..........  $7,160,110,336
Cash.......................................           7,044
Interest receivable........................      13,060,782
Prepaid expenses and other assets..........          98,115
                                             --------------
        TOTAL ASSETS.......................   7,173,276,277
                                             --------------
LIABILITIES:
Payable for:
  Investment management fee................       1,641,346
  Plan of distribution fee.................         557,085
  Shares of beneficial interest
    repurchased............................           1,953
Accrued expenses and other payables........         932,603
                                             --------------
        TOTAL LIABILITIES..................       3,132,987
                                             --------------
NET ASSETS:
Paid-in-capital............................   7,170,136,722
Accumulated undistributed net investment
  income...................................           6,568
                                             --------------
        NET ASSETS.........................  $7,170,143,290
                                             --------------
                                             --------------
NET ASSET VALUE PER SHARE, 7,170,136,722
 shares outstanding (unlimited shares
 authorized of $.01 par value).............
                                                      $1.00
                                             --------------
                                             --------------
</TABLE>
    
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                            <C>
NET INVESTMENT INCOME:
INTEREST INCOME..............................  $ 376,507,894
                                               -------------
EXPENSES
  Investment management fee..................     19,802,633
  Plan of distribution fee...................      6,495,409
  Transfer agent fees and expenses...........      3,112,938
  Registration fees..........................      1,274,800
  Custodian fees.............................        278,338
  Shareholder reports and notices............        205,750
  Professional fees..........................         58,233
  Trustees' fees and expenses................         17,465
  Other......................................         68,425
                                               -------------
      TOTAL EXPENSES.........................     31,313,991
                                               -------------
      NET INVESTMENT INCOME AND
        NET INCREASE.........................  $ 345,193,903
                                               -------------
                                               -------------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                   JUNE 30, 1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income......................................................   $    345,193,903    $    255,626,693
    Net realized gain..........................................................          --                     92,427
                                                                                 ------------------  ------------------
        Net increase...........................................................        345,193,903         255,719,120
                                                                                 ------------------  ------------------
  Dividends and distributions from:
    Net investment income......................................................       (345,191,836)       (255,627,418)
    Net realized gain..........................................................          --                    (92,427)
                                                                                 ------------------  ------------------
        Total..................................................................       (345,191,836)       (255,719,845)
                                                                                 ------------------  ------------------
    Net increase from transactions in shares of beneficial interest............      1,461,230,225       1,564,838,536
                                                                                 ------------------  ------------------
        Total increase.........................................................      1,461,232,292       1,564,837,811
NET ASSETS:
  Beginning of period..........................................................      5,708,910,998       4,144,073,187
                                                                                 ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $6,568 and
   $4,501, respectively).......................................................   $  7,170,143,290    $  5,708,910,998
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       10
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION  AND  ACCOUNTING  POLICIES--Active  Assets  Money  Trust (the
"Trust") is registered under the Investment Company Act of 1940, as amended (the
"Act"), as a  diversified, open-end management  investment company. The  Trust's
investment  objective  is  high  current  income,  preservation  of  capital and
liquidity. The Trust was  organized as a Massachusetts  business trust on  March
30, 1981 and commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that affect  the reported  amounts and  disclosures. Actual results
could differ from  those estimates. The  following is a  summary of  significant
accounting policies:
 
    A.   VALUATION OF INVESTMENTS--Portfolio  securities are valued at amortized
    cost, which approximates market value.
 
    B.  ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for  on
    the  trade date (date the order to  buy or sell is executed). Realized gains
    and losses on security  transactions are determined  by the identified  cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.   FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies and to distribute all of its taxable and nontaxable income to  its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement with Dean  Witter InterCapital  Inc. (the  "Investment Manager"),  the
Trust  pays the Investment  Manager a management fee,  accrued daily and payable
monthly, by applying the following annual rates  to the net assets of the  Trust
determined  as of the  close of each business  day: 0.50% to  the portion of the
daily net assets not exceeding $500 million; 0.425% to the portion of the  daily
net  assets exceeding $500 million but not exceeding $750 million; 0.375% to the
portion of the  daily net  assets exceeding $750  million but  not exceeding  $1
billion;  0.35% to the portion of the  daily net assets exceeding $1 billion but
not exceeding  $1.5 billion;  0.325% to  the  portion of  the daily  net  assets
exceeding $1.5 billion but not exceeding $2 billion; 0.30% to the portion of the
daily  net assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% to
the portion of the daily net assets exceeding $2.5 billion but not exceeding  $3
billion; and 0.25% to the portion of the daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the   Trustees    determine   to    reimburse,   as    described   below.    The
 
                                       11
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
following  activities and services may be  provided by the Distributor and other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average daily net assets. For the year ended June 30, 1996, the distribution fee
was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases and proceeds  from sales/maturities  of portfolio  securities for  the
year  ended  June  30,  1996  aggregated  $23,586,285,233  and  $22,455,376,131,
respectively.
 
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $236,000.
 
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent  Trustees  of  the  Trust  who  will  have  served as
independent Trustees for at least five years at the time of retirement. Benefits
under this plan are based on years  of service and compensation during the  last
five  years of service. Aggregate pension costs for the year ended June 30, 1996
included in Trustees' fees and expenses in the Statement of Operations  amounted
to  $1,238. At  June 30,  1996, the  Trust had  an accrued  pension liability of
$48,883 which is  included in accrued  expenses in the  Statement of Assets  and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                   JUNE 30, 1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
Shares sold....................................................................      26,645,844,853      21,295,444,660
Shares issued in reinvestment of dividends.....................................         344,415,057         255,223,533
                                                                                 ------------------  ------------------
                                                                                     26,990,259,910      21,550,668,193
Shares repurchased.............................................................     (25,529,029,685)    (19,985,829,657)
                                                                                 ------------------  ------------------
Net increase in shares outstanding.............................................       1,461,230,225       1,564,838,536
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
    
 
6.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
 
                                       12
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
COMMERCIAL PAPER (76.6%)
                          AUTOMOTIVE - FINANCE (6.5%)
$  121,150   Ford Motor Credit Co.
              07/12/96 - 10/11/96......  5.36 - 5.53  % $   120,550,912
   345,650   General Motors Acceptance
              Corp. 07/02/96 -
              01/17/97.................  5.07 - 5.67        341,847,614
                                                        ---------------
                                                            462,398,526
                                                        ---------------
BANK HOLDING COMPANIES (13.7%)
   180,300   BankAmerica Corp. 07/30/96
              - 11/18/96...............  5.23 - 5.48        178,351,622
   150,000   Chase Manhattan Corp.
              09/10/96 - 12/30/96......  5.44 - 5.47        147,566,778
    20,000   Corestates Capital Corp.
              07/16/96.................      5.15            19,952,306
   105,000   Fleet Financial Group,
              Inc. 07/08/96 -
              08/08/96.................  5.37 - 5.39        104,683,350
    70,000   Mellon Financial Co.
              08/07/96.................      5.38            69,595,808
   320,000   Morgan (J.P.) & Co. Inc.
              08/01/96 - 12/20/96......  5.00 - 5.62        316,608,272
    30,000   NationsBank Corp.
              09/27/96.................      5.46            29,600,250
    67,850   PNC Funding Corp. 08/12/96
              - 09/17/96...............  5.47 - 5.49         67,237,469
    50,000   Republic New York Corp.
              07/12/96.................      5.05            49,910,805
                                                        ---------------
                                                            983,506,660
                                                        ---------------
BANKS - COMMERCIAL (27.6%)
   359,400   Abbey National North
              America Corp.
              08/09/96 - 12/26/96......  5.00 - 5.65        352,786,118
   237,890   ABN-AMRO North America
              Finance Inc. 08/23/96 -
              12/20/96.................  5.00 - 5.50        234,578,741
   240,000   Canadian Imperial Holdings
              Inc.
              07/08/96 - 09/13/96......  5.35 - 5.52        237,777,503
    33,475   Commerzbank U.S. Finance
              Inc. 08/13/96............      5.36            33,253,646
   295,000   Deutsche Bank Financial
              Inc. 07/19/96 -
              12/31/96.................  4.97 - 5.62        291,696,197
   182,850   Dresdner U.S. Finance Inc.
              07/22/96 - 12/09/96......  5.05 - 5.56        180,394,941
    95,000   International Nederlanden
              (U.S.) Funding Corp.
              07/09/96.................      5.34            94,860,931
   145,000   National Australia Funding
              (DE) Inc. 08/05/96 -
              11/07/96.................  5.14 - 5.50        143,524,856
    30,000   SBC Finance (DE) Inc.
              12/27/96.................      5.64            29,173,433
 
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
 $ 210,000   Toronto-Dominion Holdings
              USA Inc. 07/11/96 -
              12/02/96.................   5.33 - 5.50%  $   207,738,700
   153,000   Union Commercial Funding
              Corp.
              07/23/96 - 11/05/96......   5.39 - 5.49       151,106,144
    19,800   WestPac Capital Corp.
              12/05/96.................      5.66            19,319,025
                                                        ---------------
                                                          1,976,210,235
                                                        ---------------
BROKERAGE (4.3%)
   230,800   Goldman Sachs Group L.P.
              07/15/96 - 09/24/96......   5.34 - 5.45       229,380,311
    80,000   Morgan Stanley Group, Inc.
              07/09/96 - 07/18/96......   5.33 - 5.34        79,816,319
                                                        ---------------
                                                            309,196,630
                                                        ---------------
                           CANADIAN GOVERNMENT (0.4%)
    25,000   British Columbia (Province
              of) 10/28/96.............      5.17            24,579,861
                                                        ---------------
CHEMICALS (0.3%)
    24,000   Monsanto Co. 08/22/96.....      5.37            23,809,920
                                                        ---------------
FINANCE - COMMERCIAL (2.5%)
   181,050   CIT Group Holdings, Inc.
              07/12/96 - 08/28/96......  5.31 - 5.43        180,250,119
                                                        ---------------
FINANCE - CONSUMER (5.5%)
   305,950   American Express Credit
              Corp.
              07/03/96 - 08/30/96......  5.13 - 5.77        305,051,328
    65,000   Avco Financial Services
              Inc. 07/08/96 -
              07/31/96.................  5.39 - 5.42         64,809,716
    27,000   Norwest Financial Inc.
              07/15/96.................      5.35            26,936,640
                                                        ---------------
                                                            396,797,684
                                                        ---------------
FINANCE - DIVERSIFIED (7.6%)
   199,000   Associates Corp. of
              North America
              07/24/96 - 10/09/96......  5.06 - 5.54        197,537,075
   354,690   General Electric Capital
              Corp.
              07/10/96 - 02/18/97......  5.14 - 5.82        349,674,892
                                                        ---------------
                                                            547,211,967
                                                        ---------------
FINANCE - EQUIPMENT (0.9%)
    66,150   Deere (John) Capital Corp.
              07/19/96 - 07/29/96......  5.34 - 5.38         65,887,828
                                                        ---------------
FOOD & BEVERAGES (0.6%)
    40,000   Coca-Cola Co. 07/25/96....      5.32            39,848,333
                                                        ---------------
INDUSTRIALS (0.2%)
    10,950   Motorola Inc. 08/12/96....      5.41            10,878,132
                                                        ---------------
</TABLE>
    
 
   
                                       13
    
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
OFFICE EQUIPMENT (2.7%)
 $  75,000   Hewlett-Packard Co.
              08/14/96 - 09/30/96......   5.26 - 5.45%  $    74,207,650
    90,000   IBM Credit Corp.
              08/19/96.................      5.42            89,315,325
    30,000   Xerox Credit Corp.
              07/29/96.................      5.34            29,868,000
                                                        ---------------
                                                            193,390,975
                                                        ---------------
                                        RETAIL (3.4%)
   247,800   Sears Roebuck Acceptance
              Corp. 07/11/96 -
              10/22/96.................  5.36 - 5.54        245,639,669
                                                        ---------------
TELEPHONES (0.4%)
    30,000   Ameritech Corp. 07/30/96..      5.33            29,864,892
                                                        ---------------
             TOTAL COMMERCIAL PAPER (AMORTIZED COST
              $5,489,471,431).........................    5,489,471,431
                                                        ---------------
SHORT-TERM BANK NOTES (12.8%)
    60,000   Bank of New York 08/23/96
              - 10/04/96...............  4.97 - 5.38         60,000,000
   259,500   F.C.C. National Bank
              07/03/96 - 09/12/96......  5.11 - 5.43        259,500,000
    55,000   First National Bank of
              Boston 07/31/96 -
              08/09/96.................  5.00 - 5.22         55,000,000
    50,000   First National Bank of
              Chicago 11/29/96.........      5.45            50,000,000
   354,000   First Union National Bank
              07/01/96 - 10/30/96......  5.00 - 5.47        354,000,000
    45,000   La Salle National Bank
              08/26/96.................      5.37            45,000,000
    95,000   NationsBank, N.A. 07/17/96
              - 08/01/96...............  5.35 - 5.48         95,000,000
                                                        ---------------
             TOTAL SHORT-TERM BANK NOTES (AMORTIZED
              COST $918,500,000)......................      918,500,000
                                                        ---------------
<CAPTION>
 PRINCIPAL                                ANNUALIZED
AMOUNT (IN        DESCRIPTION AND        YIELD ON DATE
THOUSANDS)         MATURITY DATES         OF PURCHASE        VALUE
- -----------  --------------------------  -------------  ---------------
<C>          <S>                         <C>            <C>
U.S. GOVERNMENT & AGENCIES OBLIGATIONS (5.2%)
 $  65,000   Federal Home Loan Banks
              07/10/96 - 01/31/97......   5.15 - 5.53%  $    64,293,638
   195,000   Federal National Mortgage
              Assoc. 08/29/96 -
              10/10/96.................   5.25 - 5.42       192,878,818
   115,000   U.S. Treasury Bills
              07/25/96 - 03/06/97......   5.14 - 5.71       112,374,654
                                                        ---------------
             TOTAL U.S. GOVERNMENT & AGENCIES
              OBLIGATIONS
              (AMORTIZED COST $369,547,110)...........      369,547,110
                                                        ---------------
CERTIFICATES OF DEPOSIT (3.1%)
    45,000   Chase Manhattan Bank (USA)
              09/20/96.................      5.40            45,000,000
   180,000   Union Bank 09/12/96 -
              11/19/96.................  5.45 - 5.55        180,000,000
                                                        ---------------
             TOTAL CERTIFICATES OF DEPOSIT (AMORTIZED
              COST $225,000,000)......................      225,000,000
                                                        ---------------
BANKERS' ACCEPTANCES (2.2%)
    33,000   Chase Manhattan Bank
              09/09/96 - 11/26/96......  5.45 - 5.55         32,433,600
    42,000   Chemical Bank
              07/30/96 - 08/19/96......  5.32 - 5.33         41,722,407
    62,500   Corestates Bank, N.A.
              08/08/96 - 11/08/96......  5.37 - 5.41         61,806,731
    10,000   First Bank, N.A.
              10/11/96.................      5.43             9,847,177
    12,000   Morgan Guaranty Tr. Co. of
              NY 10/30/96..............      5.46            11,781,880
                                                        ---------------
             TOTAL BANKERS' ACCEPTANCES (AMORTIZED
              COST $157,591,795)......................      157,591,795
                                                        ---------------
</TABLE>
    
 
   
<TABLE>
<S>                                            <C>      <C>
TOTAL INVESTMENTS (AMORTIZED COST
  $7,160,110,336) (A)........................   99.9 %   7,160,110,336
CASH AND OTHER ASSETS IN EXCESS OF
  LIABILITIES................................    0.1        10,032,954
                                               ------   --------------
NET ASSETS...................................  100.0 %  $7,170,143,290
                                               ------   --------------
                                               ------   --------------
<FN>
- -------------
(A) COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       14
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
ACTIVE ASSETS MONEY TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets Money Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material respects, the financial position of Active Assets Money Trust (the
"Trust") at June  30, 1996,  the results  of its  operations for  the year  then
ended,  the changes in  its net assets for  each of the two  years in the period
then ended and the financial highlights for each of the ten years in the  period
then  ended, in conformity with  generally accepted accounting principles. These
financial  statements  and  financial  highlights  (hereafter  referred  to   as
"financial  statements") are the  responsibility of the  Trust's management; our
responsibility is to express an opinion  on these financial statements based  on
our  audits. We conducted our audits of these financial statements in accordance
with generally  accepted  auditing standards  which  require that  we  plan  and
perform  the audit  to obtain reasonable  assurance about  whether the financial
statements are free of material misstatement. An audit includes examining, on  a
test  basis, evidence  supporting the amounts  and disclosures  in the financial
statements, assessing the accounting  principles used and significant  estimates
made by management, and evaluating the overall financial statement presentation.
We  believe that our  audits, which included confirmation  of securities at June
30, 1996 by correspondence  with the custodian, provide  a reasonable basis  for
the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                                       15
                           ACTIVE ASSETS MONEY TRUST
<PAGE>
   
STATEMENTS OF ADDITIONAL INFORMATION
AUGUST 22, 1996                                                           [LOGO]
    
 
- --------------------------------------------------------------------------------
 
    Active  Assets Money Trust (the "Money Trust"  or the "Trust") is a no-load,
diversified open-end management investment  company whose investment  objectives
are  high current income, preservation of capital and liquidity. The Money Trust
seeks to  achieve its  objectives by  investing in  a diversified  portfolio  of
short-term money market instruments.
 
    Active  Assets Tax-Free  Trust (the  "Tax-Free Trust"  or the  "Trust") is a
no-load, diversified  open-end management  investment company  whose  investment
objective  is to  provide as high  a level  of daily income  exempt from federal
personal income tax as is consistent with stability of principal and  liquidity.
The Tax-Free Trust seeks to achieve its objective by investing primarily in high
quality tax-exempt securities with short-term maturities.
 
    Active  Assets California Tax-Free Trust (the "California Tax-Free Trust" or
the "Trust") is  a no-load, diversified  open-end management investment  company
whose  investment objective is to provide as high a level of daily income exempt
from federal and California personal income tax as is consistent with  stability
of  principal and liquidity. The California  Tax-Free Trust seeks to achieve its
objective by  investing primarily  in high  quality tax-exempt  securities  with
short-term maturities.
 
    Active Assets Government Securities Trust (the "Government Securities Trust"
or the "Trust") is a no-load, diversified open-end management investment company
whose investment objectives are high current income, preservation of capital and
liquidity.  The Government  Securities Trust seeks  to achieve  its objective by
investing in U.S. Government securities, including a variety of securities which
are issued  or guaranteed  by  the United  States  Government, its  agencies  or
instrumentalities.
 
   
    Prospectuses  for  the  Money  Trust,  the  Tax-Free  Trust,  the California
Tax-Free Trust and the Government Securities  Trust, all dated August 22,  1996,
which  provide the basic information you should  know before investing in any of
the aforementioned Trusts, may be obtained without charge from any of the Trusts
at the address or telephone number listed below. These Statements of  Additional
Information  are not Prospectuses.  They contain information  in addition to and
more detailed than  that set  forth in the  Prospectuses. They  are intended  to
provide  additional information regarding  the activities and  operations of the
Trusts, and should be read in conjunction with the Prospectuses. They should  be
read  with the information appearing  in the Appendix hereto  which is a part of
these Statements of Additional Information.
    
 
Active Assets Money Trust
Active Assets Tax-Free Trust
Active Assets California Tax-Free Trust
Active Assets Government Securities Trust
 
Two World Trade Center
New York, New York 10048
(212) 392-2550
 
    The shares of the Money Trust,  the Tax-Free Trust, the California  Tax-Free
Trust  and the  Government Securities Trust  are offered to  participants in the
Active Assets Account program of Dean  Witter Reynolds Inc. ("Dean Witter").  In
addition,  shares of the  Trusts are offered  to investors maintaining brokerage
accounts with Dean Witter who are not subscribers to the Active Assets  program.
For  further information,  either consult  the Dean  Witter Client  Agreement or
consult your Dean Witter Account Executive.
 
Active Assets Tax-Free Trust
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
TABLE OF CONTENTS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                                                     <C>
Investment Practices and Policies.....................................      3
 
Investment Restrictions...............................................      6
 
How Net Asset Value is Determined.....................................      7
 
Dividends, Distributions and Taxes....................................      9
 
Financial Statements..................................................     13
 
Report of Independent Accountants.....................................     23
 
APPENDIX
 
Investment Manager....................................................    A-1
 
Trustees and Officers.................................................    A-7
 
Portfolio Transactions and Brokerage..................................   A-15
 
General Information...................................................   A-16
 
Custodian and Transfer Agent..........................................   A-16
 
Independent Accountants...............................................   A-17
 
Reports to Shareholders...............................................   A-17
 
Legal Counsel.........................................................   A-17
 
Experts...............................................................   A-17
 
Registration Statement................................................   A-17
 
Information with Respect to Securities Ratings........................   A-17
</TABLE>
    
 
Active Assets Tax-Free Trust           2
<PAGE>
INVESTMENT PRACTICES AND POLICIES
- --------------------------------------------------------------------------------
 
    MUNICIPAL BONDS.   Municipal Bonds, as  referred to in  the Prospectus,  are
debt  obligations of states, cities,  municipalities and municipal agencies (all
of which are generally referred to  as "municipalities") which generally have  a
maturity  at the time of issuance of one  year or more. They are issued to raise
funds for  various public  purposes, such  as construction  of a  wide range  of
public  facilities, to  refund outstanding obligations  and to  obtain funds for
general  operating  expenses  or  to  loan  to  other  public  institutions  and
facilities.  In  addition, certain  types  of industrial  development  bonds and
pollution control bonds  are issued  by or on  behalf of  public authorities  to
provide funding for various privately operated facilities.
 
    MUNICIPAL   NOTES.     Municipal   Notes   are  short-term   obligations  of
municipalities, generally with a maturity, at the time of issuance, ranging from
six months to three  years. The principal types  of Municipal Notes include  tax
anticipation  notes,  bond anticipation  notes,  revenue anticipation  notes and
project notes. In addition,  there are other types  of Municipal Notes in  which
the  Trust may invest. Notes sold in anticipation of collection of taxes, a bond
sale, or  receipt of  other  revenues are  usually  general obligations  of  the
issuing  municipality or agency. Project Notes  are issued by local agencies and
are guaranteed by the United States Department of Housing and Urban Development.
Such notes are secured by the full faith and credit of the United States.
 
    The two principal classifications of Municipal Bonds and Notes are  "general
obligation" and "revenue" bonds or notes. General obligation bonds and notes are
secured  by the issuer's pledge  of its faith, credit,  and taxing power for the
payment of principal and interest. Issuers of general obligation bonds and notes
include states, counties,  cities, towns and  other governmental units.  Revenue
bonds and notes are payable from the revenues derived from a particular facility
or class of facilities or, in some cases, from specific revenue sources. Revenue
bonds  and notes and commercial paper are issued for a wide variety of purposes,
including the financing  of electric,  gas, water  and sewer  systems and  other
public  utilities;  industrial  development  and  pollution  control facilities;
single and multi-family housing units; public buildings and facilities; air  and
marine ports; transportation facilities such as toll roads, bridges and tunnels;
and  health and educational  facilities such as  hospitals and dormitories. They
rely primarily on user fees to  pay debt service although the principal  revenue
source  is often supplemented by additional security features which are intended
to enhance  the creditworthiness  of the  issuer's obligations.  In some  cases,
particularly  in the  instance of  revenue bonds  issued to  finance housing and
public buildings, a direct or implied "moral obligation" of a governmental  unit
may  be pledged to the payment of debt service. In other cases, a special tax or
other charge may augment user fees.
 
    Obligations of issuers of Municipal Bonds and Municipal Notes are subject to
the provisions of bankruptcy, insolvency and other laws affecting the rights and
remedies of creditors,  such as the  Federal Bankruptcy Act,  and laws, if  any,
which  may be enacted by  Congress or state legislatures  to extend the time for
payment of principal or interest, or  both, or to impose other constraints  upon
enforcement  of such obligations or upon  municipalities to levy taxes. There is
also the possibility that,  as a result of  litigation or other conditions,  the
power  or ability of any one  or more issuer to pay,  when due, principal of and
interest on its, or their, Municipal Bonds and Municipal Notes may be materially
affected.
 
    VARIABLE RATE AND FLOATING RATE OBLIGATIONS.   As stated in the  Prospectus,
the  Trust  may  invest  in  Municipal  Bonds  and  Municipal  Notes ("Municipal
Obligations")  of  the   type  called  "variable   rate"  and  "floating   rate"
obligations.
 
    The  interest  rate  payable  on a  variable  rate  Municipal  Obligation is
adjusted either  at  predesignated  periodic  intervals  and  on  floating  rate
Municipal Obligations, whenever there is a change in the market rate of interest
on  which the  interest rate  payable is based.  Other features  may include the
right whereby the  Trust may demand  prepayment of the  principal amount of  the
obligation  prior to its stated  maturity (a "demand feature")  and the right of
the issuer  to prepay  the principal  amount prior  to maturity.  The  principal
benefit  of a variable rate and a floating rate Municipal Obligation is that the
interest  rate  adjustment  minimizes  changes  in  the  market  value  of   the
obligation.  As  a result,  the  purchases of  variable  rate and  floating rate
Municipal Obligations  could enhance  the ability  of the  Trust to  maintain  a
 
Active Assets Tax-Free Trust           3
<PAGE>
stable net asset value per share (see "How Net Asset Value is Determined" in the
Prospectus")  and to  sell Municipal  Obligations prior  to maturity  at a price
approximating the full principal amount of the obligation. The principal benefit
to the Trust of purchasing Municipal  Obligations with a demand feature is  that
liquidity,  and  the  ability of  the  Trust  to obtain  repayment  of  the full
principal amount of a Municipal Obligation  prior to maturity, is enhanced.  The
payment  of principal and  interest by issuers  of certain Municipal Obligations
purchased by the Trust may  be guaranteed by letters  of credit or other  credit
facilities  offered by  banks or  other financial  institutions. Such guarantees
will be  considered in  determining  whether a  Municipal Obligation  meets  the
Trust's investment quality requirements.
 
   
    WHEN-ISSUED  AND DELAYED DELIVERY SECURITIES.   As stated in the Prospectus,
the Trust  may  purchase  tax-exempt  securities on  a  when-issued  or  delayed
delivery basis. When such transactions are negotiated, the price is fixed at the
time  of commitment,  but delivery and  payment can  take place a  month or more
after the date of the commitment. While the Trust will only purchase  securities
on  a when-issued or delayed delivery basis  with the intention of acquiring the
securities, the Trust may sell the securities before the settlement date, if  it
is  deemed advisable. The securities so purchased  or sold are subject to market
fluctuation and no interest accrues to the purchaser during this period. At  the
time  the Trust  makes the  commitment to purchase  a Municipal  Obligation on a
when-issued or  delayed  delivery basis,  it  will record  the  transaction  and
thereafter  reflect  the  value,  each  day,  of  the  Municipal  Obligation  in
determining its net  asset value.  The Trust  will also  establish a  segregated
account  with  its  custodian  bank  in which  it  will  maintain  cash  or cash
equivalents or other  Municipal Obligations  equal in value  to commitments  for
such when-issued or delayed delivery securities.
    
 
    REPURCHASE  AGREEMENTS.  When cash may be  available for only a few days, it
may be invested by the Trust in repurchase agreements until such time as it  may
otherwise  be invested or used  for payments of obligations  of the Trust. These
agreements, which may  be viewed  as a  type of  secured lending  by the  Trust,
typically involve the acquisition by the Trust of debt securities from a selling
financial   institution  such  as  a  bank,  savings  and  loan  association  or
broker-dealer. The  agreement provides  that the  Trust will  sell back  to  the
institution,  and that the institution  will repurchase, the underlying security
("collateral") at a specified price and at a fixed time in the future, which  is
usually  not more  than seven  days from  the date  of purchase.  The Trust will
receive interest from the institution until  the time when the repurchase is  to
occur.  Although such date is deemed  by the Trust to be  the maturity date of a
repurchase  agreement,  the  maturities  of  securities  subject  to  repurchase
agreements are not subject to any limits and may exceed one year.
 
   
    While repurchase agreements involve certain risks not associated with direct
investments  in  debt  securities,  the  Trust  follows  procedures  designed to
minimize such risks. These procedures include effecting repurchase  transactions
only  with large, well capitalized  and well established financial institutions,
whose financial condition will be continuously monitored. In addition, the value
of the collateral underlying  the repurchase agreement will  always be at  least
equal  to the  resale price  which consists  of the  purchase price  paid to the
seller of the securities plus the accrued resale premium which is defined as the
amount specified in the  repurchase agreement or the  daily amortization of  the
difference  between the  purchase price  and the  resale price  specified in the
repurchase agreement. Such collateral will  consist entirely of securities  that
are  direct obligations  of, or  that are fully  guaranteed as  to principal and
interest by, the  United States or  any agency thereof,  and/or certificates  of
deposit,  bankers' acceptances  which are eligible  for acceptance  by a Federal
Reserve Bank, and, if the seller is a bank, mortgage related securities (as such
term is defined in section 3(a)(41) of the Securities Exchange Act of 1934 that,
at the time the repurchase agreement is  entered into, are rated in the  highest
rating  category  by the  Requisite  NRSROs. Additionally,  the  collateral must
qualify the repurchase  agreement for preferential  treatment under the  Federal
Deposit  Insurance Act or the Federal Bankruptcy Code. In the event of a default
or bankruptcy  by  a selling  financial  institution,  the Trust  will  seek  to
liquidate  such  collateral. However,  the exercising  of  the Trust's  right to
liquidate such collateral  could involve  certain costs  or delays  and, to  the
extent  that  proceeds  from  any  sale upon  a  default  of  the  obligation to
repurchase were less than the repurchase  price, the Trust could suffer a  loss.
It  is the current  policy of the  Trust not to  invest in repurchase agreements
that do not mature within seven days  if any such investment, together with  any
other  illiquid assets held by  the Trust, amount to more  than 10% of its total
assets. The Trust's
    
 
Active Assets Tax-Free Trust           4
<PAGE>
   
investments in repurchase agreements  may at times be  substantial when, in  the
view  of  the  Trust's  investment manager,  liquidity  or  other considerations
warrant. However, during the fiscal year ended June 30, 1996, the Trust did  not
enter into any repurchase agreements and the Trust does not intend to enter into
any repurchase agreements during the foreseeable future.
    
 
    PUT  OPTIONS.  The Trust may purchase  securities together with the right to
resell them to the seller  at an agreed upon price  or yield within a  specified
period  prior to the maturity date of such securities. Such a right to resell is
commonly known as  a "put," and  the aggregate  price which the  Trust pays  for
securities  with puts may be higher than the price which otherwise would be paid
for the  securities.  Consistent  with the  Trust's  investment  objectives  and
subject  to the supervision of the Trust's Trustees, the primary purpose of this
practice is to permit the Trust to be fully invested in securities the  interest
on  which is  exempt from  Federal income  taxes while  preserving the necessary
flexibility and liquidity to purchase securities on a when-issued basis, to meet
unusually large redemptions and to purchase,  at a later date, securities  other
than  those subject to the put. The  Trust's policy is generally to exercise the
puts on  their expiration  date, when  the  exercise price  is higher  than  the
current  market price for the related securities. Puts may be exercised prior to
the expiration date in order to fund obligations to purchase other securities or
to meet redemption requests. These obligations may arise during periods in which
proceeds from  sales  of  Trust  shares  and  from  recent  sales  of  portfolio
securities are insufficient to meet such obligations or when the funds available
are otherwise allocated for investment. In addition, puts may be exercised prior
to  their  expiration  date in  the  event  the Investment  Manager  revises its
evaluation of the creditworthiness of the issuer of the underlying security.  In
determining  whether  to exercise  puts prior  to their  expiration date  and in
selecting which puts to exercise  in such circumstances, the Investment  Manager
considers,  among other things, the  amount of cash available  to the Trust, the
expiration dates of the  available puts, any  future commitments for  securities
purchases,  the yield, quality and maturity  dates of the underlying securities,
alternative investment  opportunities  and  the desirability  of  retaining  the
underlying securities in the Trust's portfolio.
 
   
    The  Trust values  securities which are  subject to puts  at their amortized
cost and values the put, apart from the security, at zero. Thus, the cost of the
put will be carried on the Trust's books as an unrealized loss from the date  of
acquisition  and will  be reflected  in realized  gain or  loss when  the put is
exercised or expires. Since the value of the put is dependent on the ability  of
the  put writer to meet  its obligation to repurchase,  the Trust's policy is to
enter into  put transactions  only  with municipal  securities dealers  who  are
approved by the Trust's Trustees. Each dealer will be approved on its own merits
and  it is the Trust's  general policy to enter  into put transactions only with
those dealers which  have been determined  to present minimal  credit risks.  In
connection  with  such  determination,  the Trustees  will  review,  among other
things, the  ratings,  if available,  of  equity  and debt  securities  of  such
municipal  securities  dealers, their  reputations  in the  municipal securities
markets, the net  worth of  such dealers  and their  efficiency in  consummating
transactions.  Bank  dealers normally  will be  members  of the  Federal Reserve
System, and  other  dealers will  be  members  of the  National  Association  of
Securities  Dealers,  Inc. or  members of  a  national securities  exchange. The
Trustees have directed the Investment Manager not to enter into put transactions
with, or to exercise outstanding puts of, any municipal securities dealer which,
in the judgment  of the  Investment Manager,  ceases at  any time  to present  a
minimal credit risk. In the event that a dealer should default on its obligation
to repurchase an underlying security, the Trust is unable to predict whether all
or  any portion of any loss sustained  could be subsequently recovered from such
dealer. During the fiscal year ended June  30, 1996, the Trust did not  purchase
any put options and it has no intention of purchasing such securities during the
coming year.
    
 
    In  Revenue Ruling 82-144,  the Internal Revenue  Service stated that, under
certain circumstances, a purchaser of  tax-exempt obligations which are  subject
to  puts will be considered the owner  of the obligations for Federal income tax
purposes. In connection therewith, the Trust has received an opinion of  counsel
to  the effect that  interest on Municipal  Obligations subject to  puts will be
tax-exempt to the Trust.
 
Active Assets Tax-Free Trust           5
<PAGE>
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    In addition to the investment restrictions enumerated in the Prospectus, the
investment  restrictions  listed  below  have  been  adopted  by  the  Trust  as
fundamental   policies,  except  as  otherwise   indicated.  Under  the  Act,  a
fundamental policy may  not be  changed without  the vote  of the  holders of  a
majority  of the outstanding voting  securities of the Trust,  as defined in the
Investment Company  Act of  1940, as  amended (the  "Act"). Such  a majority  is
defined  in the Act as the lesser of (a)  67% or more of the shares present at a
Meeting of Shareholders of  the Trust, if  the holders of more  than 50% of  the
outstanding  shares of  the Trust  are present  or represented  by proxy  at the
meeting or  (b) more  than  50% of  the outstanding  shares  of the  Trust.  For
purposes  of the following  restrictions and those  contained in the Prospectus:
(a) an  "issuer" of  a security  is the  entity whose  assets and  revenues  are
committed  to the payment of interest and principal on that particular security,
provided that  the  guarantee  of  a security  will  be  considered  a  separate
security;  (b) a  "taxable security"  is any security  the interest  on which is
subject to  federal  income  tax;  and  (c)  all  percentage  limitations  apply
immediately after a purchase or initial investment, and any subsequent change in
any applicable percentage resulting from market fluctuations or other changes in
total  or  net assets  does not  require  elimination of  any security  from the
portfolio.
 
    The restrictions provide that the Trust may not:
 
         1. Invest in common stock;
 
         2. Invest  in securities  of any  issuer if,  to the  knowledge of  the
    Trust,  any officer, Trustee or  director of the Trust  or of the Investment
    Manager owns  more than  1/2 of  1% of  the outstanding  securities of  such
    issuer,  and such officers, Trustees and directors  who own more than 1/2 of
    1% own in the aggregate more than  5% of the outstanding securities of  such
    issuer;
 
         3.  Purchase or sell real estate  or interests therein, although it may
    purchase securities secured by real estate or interests therein;
 
         4. Purchase or sell commodities or commodity futures contracts;
 
         5. Purchase  oil,  gas  or  other mineral  leases,  rights  or  royalty
    contracts, or exploration or development programs;
 
         6.  Write, purchase or sell puts, calls, or combinations thereof except
    that it may acquire rights to resell Municipal Obligations at an agreed upon
    price and at or within an agreed upon time;
 
         7.  Purchase  securities  of  other  investment  companies,  except  in
    connection  with a  merger, consolidation, reorganization  or acquisition of
    assets;
 
         8. Pledge its  assets or assign  or otherwise encumber  them except  to
    secure  borrowings effected within  the limitations set  forth in Investment
    Restriction 5, as disclosed in the  Prospectus. To meet the requirements  of
    regulations  in certain states,  the Trust, as a  matter of operating policy
    but not as a fundamental policy, will limit any pledge of its assets to  10%
    of  its net assets  so long as shares  of the Trust are  being sold in those
    states;
 
         9. Issue senior securities as defined in the Act except insofar as  the
    Trust  may be  deemed to  have issued  a senior  security by  reason of: (a)
    entering into any repurchase agreement;  (b) purchasing any securities on  a
    when-issued  or delayed delivery basis; or (c) borrowing money in accordance
    with restrictions described above;
 
        10. Make loans of  money or securities, except:  (a) by the purchase  of
    debt  obligations  in  which  the  Trust  may  invest  consistent  with  its
    investment objective  and  policies; and  (b)  by investment  in  repurchase
    agreements;
 
        11. Make short sales of securities;
 
        12.  Purchase securities on margin, except  for such short-term loans as
    are necessary for the clearance of purchases of portfolio securities;
 
Active Assets Tax-Free Trust           6
<PAGE>
        13. Engage  in the  underwriting of  securities, except  insofar as  the
    Trust  may be  deemed an  underwriter under  the Securities  Act of  1933 in
    disposing of a portfolio security; and
 
        14. Invest for the  purpose of exercising control  or management of  any
    other issuer.
 
HOW NET ASSET VALUE IS DETERMINED
- --------------------------------------------------------------------------------
 
    As  discussed in the Appendix to the  Prospectus, the net asset value of the
Trust is determined as of 12  noon New York time on  each day that the New  York
Stock  Exchange  is open.  The New  York Stock  Exchange currently  observes the
following holidays: New Year's Day; President's Day; Good Friday; Memorial  Day;
Independence Day; Labor Day; Thanksgiving Day; and Christmas Day.
 
    The  Trust  utilizes  the amortized  cost  method in  valuing  its portfolio
securities for  purposes of  determining  the net  asset  value of  the  Trust's
shares.  The Trust utilizes  the amortized cost method  in valuing its portfolio
securities even  though the  portfolio securities  may increase  or decrease  in
market  value,  generally, in  connection with  changes  in interest  rates. The
amortized cost  method of  valuation involves  valuing a  security at  its  cost
adjusted  by a  constant amortization  to maturity  of any  discount or premium,
regardless of the impact  of fluctuating interest rates  on the market value  of
the instrument. While this method provides certainty in valuation, it may result
in  periods during which  value, as determined  by amortized cost,  is higher or
lower than the price the Trust would  receive it if sold the instrument.  During
such  periods, the yield to investors in the Trust may differ somewhat from that
obtained in a  similar company  which uses  mark to  market values  for all  its
portfolio  securities. For example, if  the use of amortized  cost resulted in a
lower (higher)  aggregate portfolio  value on  a particular  day, a  prospective
investor  in the Trust would  be able to obtain  a somewhat higher (lower) yield
than would  result  from investment  in  such  a similar  company  and  existing
investors  would  receive less  (more) investment  income.  The purpose  of this
method of calculation is to facilitate  the maintenance of a constant net  asset
value per share of $1.00.
 
    The  Trust's  use  of  the  amortized cost  method  to  value  its portfolio
securities and the  maintenance of the  per share  net asset value  of $1.00  is
permitted  pursuant to Rule 2a-7 of the  Act (the "Rule"), and is conditioned on
its compliance with various conditions contained in the Rule including: (a)  the
Trust's  Trustees  are  obligated,  as a  particular  responsibility  within the
overall duty of care owed to  the Trust's shareholders, to establish  procedures
reasonably  designed,  taking into  account  current market  conditions  and the
Trust's investment objectives,  to stabilize the  net asset value  per share  as
computed  for the purpose of distribution and redemption at $1.00 per share; (b)
(i) the procedures include calculation, at  such intervals as are reasonable  in
light  of current market conditions, of the  deviation, if any between net asset
value per share using amortized cost to value portfolio securities and net asset
value per share  based upon  available market  quotations with  respect to  such
portfolio securities (for the purpose of determining market value, securities as
to  which the Trust has a "put" will be  valued at the higher of market value or
exercise price); (ii) periodic review by the Trustees of the amount of deviation
as well  as methods  used to  calculate  it, and  (iii) maintenance  of  written
records of the procedures, the Trustees considerations made pursuant to them and
any actions taken upon such consideration; the Trustees will consider what steps
should  be taken, if any,  in the event of  a difference of more  than 1/2 of 1%
between the two  methods of  valuation; and (d)  the Trustees  should take  such
action as they deem appropriate to eliminate or reduce, to the extent reasonably
practicable,  material dilution or other unfair results to investors or existing
shareholders. Such action  may include: selling  portfolio instruments prior  to
maturity  to realize capital gains or losses or to shorten the average portfolio
maturity of the Trust;  withholding dividends; utilizing a  net asset value  per
share  as determined by using available market quotations or reducing the number
of its outstanding shares. Any reduction of outstanding shares will be  effected
by  having each shareholder proportionately contribute  to the Trust's capital a
number of  shares which  represent  the difference  between the  amortized  cost
valuation and market valuation of the portfolio. Each shareholder will be deemed
to have agreed to such contribution by his or her investment in the Trust.
 
    The  Rule  further requires  that the  Trust limit  its investments  to U.S.
dollar-denominated instruments  which  the Trustees  determine  present  minimal
credit    risks    and    which   are    Eligible    Securities    (as   defined
 
Active Assets Tax-Free Trust           7
<PAGE>
below). The Rule also requires the  Trust to maintain a dollar-weighted  average
portfolio  maturity  (not more  than 90  days) appropriate  to its  objective of
maintaining a  stable net  asset value  of  $1.00 per  share and  precludes  the
purchase  of  any instrument  with a  remaining maturity  of more  than thirteen
months.  Should  the   disposition  of   a  portfolio  security   result  in   a
dollar-weighted  average portfolio maturity of more than 90 days, the Trust will
invest its available cash in such a manner as to reduce such maturity to 90 days
or less as soon as is reasonably practicable.
 
    At the  time  the  Trust  makes  the  commitment  to  purchase  a  Municipal
Obligation  on  a when-issued  or  delayed delivery  basis,  it will  record the
transaction and  thereafter  reflect  the  value, each  day,  of  the  Municipal
Obligation  in determining its net asset value. Repurchase agreements are valued
at the face value of the repurchase agreement plus any accrued interest  thereon
to date.
 
    Generally,  for  purposes  of the  procedures  adopted under  the  Rule, the
maturity of  a  portfolio  instrument  is deemed  to  be  the  period  remaining
(calculated from the trade date or such other date on which the Trust's interest
in  the instrument is subject to market action) until the date noted on the face
of the instrument as the date on which the principal amount must be paid, or  in
the  case  of  an  instrument  called for  redemption,  the  date  on  which the
redemption payment must be made.
 
    A variable rate obligation that is subject to a demand feature is deemed  to
have  a maturity  equal to  the longer  of the  period remaining  until the next
readjustment of the interest  rate or the period  remaining until the  principal
amount  can  be recovered  through demand.  A floating  rate instrument  that is
subject to a demand  feature is deemed  to have a maturity  equal to the  period
remaining until the principal amount can be recovered through demand.
 
   
    An Eligible Security generally is defined in the Rule to mean (i) A security
with  a remaining  maturity of  397 calendar  days or  less that  has received a
short-term rating (or  that has been  issued by  an issuer that  has received  a
short-term  rating with  respect to  a class  of debt  obligations, or  any debt
obligation within that class, that is  comparable in priority and security  with
the  security) by  the Requisite  NRSROs in  one of  the two  highest short-term
rating categories  (within  which  there may  be  sub-categories  or  gradations
indicating  relative standing);  or (ii)  A security:  (A) That  at the  time of
issuance had a remaining maturity of more than 397 calendar days but that has  a
remaining  maturity  of 397  calendar days  or  less; and  (B) Whose  issuer has
received from the  Requisite NRSROs a  rating with  respect to a  class of  debt
obligations (or any debt obligation within that class) that is now comparable in
priority  and security with the  security, in one of  the two highest short-term
rating categories  (within  which  there may  be  sub-categories  or  gradations
indicating  relative  standing);  or  (iii)  An  Unrated  Security  that  is  of
comparable quality to a security meeting the requirements of (i) or (ii)  above,
as  determined by  the money  market fund's board  of directors.  The Trust will
limit its  investments to  securities that  meet the  requirements for  Eligible
Securities, as set forth in the prospectus.
    
 
    As  permitted by the Rule, the Board has delegated to the Trust's Investment
Manager, subject to the Board's oversight pursuant to guidelines and  procedures
adopted  by  the  Board, the  authority  to determine  which  securities present
minimal credit risks and which unrated  securities are comparable in quality  to
rated securities.
 
   
    Also,  as required  by the  Rule, the  Trust will  limit its  investments in
securities, other than Government securities, so that, at the time of  purchase:
(a) except as further limited in (b) below with regard to certain securities, no
more  than 5% of its total assets will  be invested in the securities of any one
issuer; and (b) with respect to Eligible Securities that have received a  rating
in  less than the  highest category by any  one of the  NRSROs whose ratings are
used to qualify the security as an Eligible Security, or are determined to be of
comparable quality that are "conduit securities" as that term is defined in  the
Rule:  (i) no more  than 5% in the  aggregate of the Trusts  total assets in all
such securities, and (ii) no more than the greater of 1% of total assets, or  $1
million, in the securities of any one issuer.
    
 
    If  the Board determines that  it is no longer in  the best interests of the
Trust and its shareholders to maintain a stable price of $1 per share or if  the
Board believes that maintaining such price no longer
 
Active Assets Tax-Free Trust           8
<PAGE>
reflects  a market-based net asset  value per share, the  Board has the right to
change from an amortized  cost basis of valuation  to valuation based on  market
quotations. The Trust will notify shareholders of any such changes.
 
    The  Trust will  manage its  portfolio in an  effort to  maintain a constant
$1.00 per share price, but  it cannot assure that the  value of its shares  will
never  deviate from the $1.00 price.  Since dividends from net investment income
are declared and reinvested  on a daily  basis, the net  asset value per  share,
under  ordinary  circumstances,  is  likely  to  remain  constant.  Realized and
unrealized gains and losses will not be distributed on a daily basis but will be
reflected in the Trust's net  asset value. The amount  of such gains and  losses
will  be considered  by the Trustees  in determining  the action to  be taken to
maintain the Trust's $1.00  per share net asset  value. Such action may  include
distribution  at any time of  part or all of  the then accumulated undistributed
net realized capital gains, or reduction or elimination of daily dividends by an
amount equal to part or all of the then accumulated net realized capital losses.
However, if realized losses should exceed the sum of net investment income  plus
realized  gains on  any day,  the net asset  value per  share on  that day might
decline below $1.00 per  share. In such circumstances,  the Trust may reduce  or
eliminate  the payment of daily  dividends for a period of  time in an effort to
restore the Trust's  $1.00 per share  net asset  value. A decline  in prices  of
securities  could result  in significant  unrealized depreciation  on a  mark to
market basis. In  these circumstances,  the Trust  may reduce  or eliminate  the
payment  of dividends and utilize  a net asset value  per share as determined by
using available  market  quotations or  reduce  the number  of  its  outstanding
shares.
 
DIVIDENDS, DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------
 
    As  stated in the Appendix  to the Prospectus, the  Trust intends to declare
dividends, payable on each day the New York Stock Exchange is open for business,
of all of its net investment income to shareholders of record as of 12 noon  New
York time of the preceding business day.
 
    In  computing  interest income,  the Trust  will  amortize any  premiums and
original issue discounts on securities  owned. Capital gains or losses  realized
upon sale or maturity of such securities will be based on their amortized cost.
 
    Gains  or losses on the  sales of securities by  the Trust will be long-term
capital gains or losses if the securities  have been held by the Trust for  more
than  twelve months. Gains or  losses on the sale  of securities held for twelve
months or less will be short-term capital gains or losses.
 
   
    During the fiscal year ended  June 30, 1996, the  Trust utilized all of  its
net capital loss carryovers of approximately $59,000. To the extent that capital
loss  carryovers are used to offset future  gains, it is probable that the gains
so offset will not be distributed to shareholders. Any net capital loss incurred
after October 31 ("post-October  losses") within the taxable  year is deemed  to
arise on the first day of the fund's next taxable year.
    
 
    The  Trustees may  revise the  dividend policy,  or postpone  the payment of
dividends, if the Trust should have or anticipate any large unexpected  expense,
loss  or fluctuation in net assets which,  in the opinion of the Trustees, might
have a significant  adverse effect  on shareholders.  On occasion,  in order  to
maintain  a constant $1.00  per share net  asset value, the  Trustees may direct
that the number of outstanding shares be reduced in each shareholder's  account.
Such  reduction may result in taxable income, if any, to a shareholder in excess
of the net  increase (i.e.,  dividends, less such  reductions), if  any, in  the
shareholder's  account for a period. Furthermore, such reduction may be realized
as a capital loss when the shares are liquidated.
 
    As discussed in the Prospectus, the Trust intends to invest a portion of its
assets in certain  "private activity bonds"  issued after August  7, 1986. As  a
result,  a portion of the exempt-interest dividends paid by the Trust will be an
item of tax  preference for  taxable years  beginning after  December 31,  1986.
Certain  corporations which are subject to  the alternative minimum tax may also
have to  include  exempt-interest  dividends in  calculating  their  alternative
minimum  taxable income in  situations where the  "adjusted current earnings" of
the corporation exceeds its preadjustment alternative minimum taxable income.
 
Active Assets Tax-Free Trust           9
<PAGE>
    The Trust  has qualified  and intends  to remain  qualified as  a  regulated
investment  company under Subchapter M  of the Code. If  so qualified, the Trust
will not be  subject to  federal income  and excise  tax on  its net  investment
income  and capital gains, if  any, realized during any  fiscal year in which it
distributes such income and capital gains to its shareholders.
 
    As discussed  in  the  Prospectus,  the Trust  intends  to  qualify  to  pay
"exempt-interest  dividends" to its shareholders by maintaining, as of the close
of each  of  its  taxable years,  at  least  50% of  its  assets  in  tax-exempt
securities.  An exempt-interest dividend is that part of a dividend distribution
made by the Trust which consists of interest received by the Trust on tax-exempt
securities  upon  which  the  shareholder   incurs  no  federal  income   taxes.
Exempt-interest dividends are included, however, in determining what portion, if
any,  of a person's Social  Security benefits are subject  to federal income tax
and in certain circumstances  may affect the  determination of the  supplemental
premium applicable to Medicare eligible individuals.
 
    Alternative minimum taxable income is generally equal to taxable income with
certain  adjustments and increased  by certain "tax  preference items" which may
include a portion of the Trust's dividends as described above. In addition,  the
Code  further provides that for taxable  years beginning in 1990 and thereafter,
corporations are subject to an alternative minimum tax based, in part, on 75% of
any excess of "adjusted  current earnings" over taxable  income as adjusted  for
other  tax preferences.  Because an exempt-interest  dividend paid  by the Trust
will be  included in  adjusted  current earnings,  a corporate  shareholder  may
therefore  be required to pay an increased alternative minimum tax as the result
of receiving exempt-interest dividends paid by the Trust.
 
    The Superfund Amendments  and Reauthorization  Act of  1986 (the  "Superfund
Act")  imposes a deductible  tax on a  corporation's alternative minimum taxable
income (computed  without  regard to  the  alternative tax  net  operating  loss
deduction)  at a rate of $12 per  $10,000 (0.12%) of alternative minimum taxable
income in  excess of  $2,000,000. The  tax  will be  imposed for  taxable  years
beginning  after December 31, 1986  and before January 1,  1996. The tax will be
imposed even if the  corporation is not required  to pay an alternative  minimum
tax  because the corporation's regular income  tax liability exceeds its minimum
tax  liability.  Exempt-interest  dividends  paid  by  the  Trust  that   create
alternative  minimum tax preferences  for corporate shareholders  under the Code
(as described above) may be subject to the tax.
 
    Within 60 days  after the end  of its fiscal  year, the Trust  will mail  to
shareholders a statement indicating the percentage of the dividend distributions
for  such  fiscal  year  which  constitutes  exempt-interest  dividends  and the
percentage, if any, that is taxable, and  to what extent the taxable portion  is
long-term  capital  gain,  short-term  capital  gain  or  ordinary  income. This
percentage should be applied uniformly to all monthly distributions made  during
the fiscal year to determine the proportion of dividends that is tax-exempt. The
percentage  may differ from the  percentage of tax-exempt dividend distributions
for any particular month.
 
    Shareholders will be subject  to federal income tax  on dividends paid  from
interest income derived from taxable securities and on distributions of realized
net  short-term capital gains. Such interest and realized net short-term capital
gains dividends and  distributions are  taxable to the  shareholder as  ordinary
dividend   income   regardless  of   whether   the  shareholder   receives  such
distributions in  additional  shares  or in  cash.  Distributions  of  long-term
capital gains, if any, are taxable as long-term capital gains, regardless of how
long  the shareholder  has held  the Fund shares  and regardless  of whether the
distribution is received in additional shares or cash. Since the Trust's  income
is  expected to be derived  entirely from interest rather  than dividends, it is
anticipated that none of  such dividend distributions will  be eligible for  the
federal dividends received deduction available to corporations.
 
    Any loss on the sale or exchange of shares of the Trust which are held for 6
months  or less is disallowed to the extent of the amount of any exempt-interest
dividend paid with respect to such shares. Treasury Regulations may provide  for
a reduction in such required holding periods.
 
    The  Code requires each regulated investment  company to pay a nondeductible
4% excise  tax  to the  extent  the company  does  not distribute,  during  each
calendar year, 98% of its ordinary income,
deter-
 
                                       10
Active Assets Tax-Free Trust
<PAGE>
mined  on a  calendar year basis,  and 98%  of its capital  gains, determined in
general on  an October  31 year  end, plus  certain undistributed  amounts  from
previous  years.  The required  distributions, however,  are  based only  on the
taxable income of a regulated investment  company such as the Trust, which  pays
exempt-interest  dividends. The Trust  anticipates that it  will make sufficient
timely distributions to avoid imposition of the excise tax.
 
    Interest on indebtedness incurred or continued by a shareholder to  purchase
or carry shares of the Trust is not deductible. Furthermore, entities or persons
who  are  "substantial users"  (or related  persons)  of facilities  financed by
industrial development bonds should consult their tax advisers before purchasing
shares of  the Trust.  "Substantial user"  is defined  generally by  Income  Tax
Regulation 1.103-11 (b) as including a "non-exempt person" who regularly uses in
a  trade  or  business  a part  of  a  facility financed  from  the  proceeds of
industrial development bonds.
 
    From time to time,  proposals have been introduced  before Congress for  the
purpose  of  restricting or  eliminating the  federal  income tax  exemption for
interest on municipal  securities. Similar  proposals may be  introduced in  the
future.  If such a proposal  were to be enacted,  the availability of tax-exempt
municipal securities for  investment by  the Trust  could be  affected. If  such
legislation  is enacted, the  Trust may reevaluate  its investment objective and
policies.
 
    The exemption of interest  income for federal income  tax purposes does  not
necessarily  result in exemption under the income or other tax laws of any state
or local taxing  authority. Thus, shareholders  of the Trust  may be subject  to
state  and local taxes on exempt-interest dividends. Shareholders should consult
their tax advisers about  the status of  dividends from the  Trust in their  own
states  and  localities.  The Trust  will  report annually  to  shareholders the
percentage of interest income received by the Trust during the preceding year on
tax-exempt obligations, indicating,  on a  state-by-state basis,  the source  of
such income.
 
    Under   present  Massachusetts  law,  the  Trust   is  not  subject  to  any
Massachusetts income tax during any fiscal year in which the Trust qualifies  as
a  regulated investment  company. The  Trust might  be subject  to Massachusetts
income taxes for any taxable year in which it does not so qualify as a regulated
investment company.
 
    Any dividends or capital gains distributions received by a shareholder  from
any  investment company will have the effect  of reducing the net asset value of
the shareholder's stock in  that fund by  the exact amount  of the dividends  or
capital  gains distribution.  Furthermore, capital gains  distributions are, and
some portion of the dividends  may be, subject to income  tax. If the net  asset
value  of the shares should be reduced below a shareholder's cost as a result of
the distribution  of realized  net long-term  capital gains,  such  distribution
would  be a return  of capital but  nonetheless taxable at  capital gains rates.
Therefore, an investor should not purchase  Trust shares immediately prior to  a
distribution  record date  and sell them  immediately thereafter  solely for the
purpose of receiving the distribution.
 
INFORMATION ON COMPUTATION OF YIELD
 
    The Trust's annualized current yield, as may be quoted from time to time  in
advertisements and other communications to shareholders and potential investors,
is  computed  by determining,  for a  stated seven-day  period, the  net change,
exclusive of  capital  changes and  including  the value  of  additional  shares
purchased  with dividends  and any  dividends declared  therefrom (which reflect
deductions of all expenses of the Trust  such as management fees), in the  value
of  a hypothetical  pre-existing account  having a balance  of one  share at the
beginning of the period, and dividing the difference by the value of the account
at the beginning of the base period  to obtain the base period return, and  then
multiplying the base period return by (365/7).
 
    The  Trust's annualized effective yield, as may  be quoted from time to time
in  advertisements  and  other  communications  to  shareholders  and  potential
investors,  is computed by determining (for  the same stated seven-day period as
for the  current  yield), the  net  change,  exclusive of  capital  changes  and
including  the  value  of additional  shares  purchased with  dividends  and any
dividends declared therefrom (which  reflect deductions of  all expenses of  the
Trust  such as  management fees),  in the  value of  a hypothetical pre-existing
account having  a balance  of one  share at  the beginning  of the  period,  and
 
Active Assets Tax-Free Trust           11
<PAGE>
dividing the difference by the value of the account at the beginning of the base
period  to obtain the base  period return, and then  compounding the base period
return by adding 1, raising the  sum to a power equal  to 365 divided by 7,  and
subtracting 1 from the result.
 
    The  yields quoted in any advertisement or other communication should not be
considered a representation of the yields of  the Trust in the future since  the
yield  is not fixed. Actual yields will depend not only on the type, quality and
maturities of the investments held by the Trust and changes in interest rates on
such investments, but also on changes in the Trust's expenses during the period.
 
    Yield information may be  useful in reviewing the  performance of the  Trust
and  for providing  a basis for  comparison with  other investment alternatives.
However, unlike bank deposits or other  investments which typically pay a  fixed
yield for a stated period of time, the Trust's yield fluctuates.
 
    Tax-equivalent  yield is  computed by dividing  that portion  of the current
yield (calculated as described  above) which is tax-exempt  by 1 minus a  stated
tax  rate and adding the quotient  to that portion, if any,  of the yield of the
Trust that is not tax-exempt.
 
   
    The Trust's current yield for the seven days ending June 30, 1996 was 2.95%.
The effective annual yield on 2.95% is 2.99%, assuming daily compounding.
    
 
   
    Based upon  a Federal  personal income  tax bracket  of 39.6%,  the  Trust's
tax-equivalent  yield  for  the  seven  days ending  June  30,  1996  was 4.88%.
Tax-equivalent yield is computed by dividing  that portion of the current  yield
(calculated as described above) which is tax-exempt by 1 minus a stated tax rate
and  adding the quotient to that portion, if any, of the yield of the Trust that
is not tax-exempt.
    
 
Active Assets Tax-Free Trust           12
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                          <C>
ASSETS:
Investments in securities, at value
  (amortized cost $1,643,339,150)..........  $1,643,339,150
Cash.......................................       2,322,982
Interest receivable........................       7,426,219
Receivable from affiliate..................       2,849,017
Prepaid expenses and other assets..........          50,662
                                             --------------
        TOTAL ASSETS.......................   1,655,988,030
                                             --------------
LIABILITIES:
Payable for:
  Investments purchased....................     113,338,770
  Investment management fee................         505,007
  Plan of distribution fee.................         123,020
Accrued expenses and other payables........         134,104
                                             --------------
        TOTAL LIABILITIES..................     114,100,901
                                             --------------
NET ASSETS:
Paid-in-capital............................   1,541,888,167
Accumulated undistributed net investment
  income...................................           1,091
Accumulated net realized loss..............          (2,129)
                                             --------------
        NET ASSETS.........................  $1,541,887,129
                                             --------------
                                             --------------
NET ASSET VALUE PER SHARE, 1,541,888,167
 shares outstanding (unlimited shares
 authorized of $.01 par value).............
                                                      $1.00
                                             --------------
                                             --------------
</TABLE>
    
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                             <C>
NET INVESTMENT INCOME:
INTEREST INCOME...............................  $58,069,820
                                                -----------
EXPENSES
  Investment management fee...................    6,571,351
  Plan of distribution fee....................    1,560,662
  Transfer agent fees and expenses............      355,031
  Registration fees...........................      145,672
  Shareholder reports and notices.............       62,080
  Professional fees...........................       54,523
  Trustees' fees and expenses.................       17,381
  Custodian fees..............................       79,140
  Other.......................................       23,721
                                                -----------
      TOTAL EXPENSES BEFORE EXPENSE OFFSET....    8,869,561
      LESS: EXPENSE OFFSET....................      (72,184)
                                                -----------
      TOTAL EXPENSES AFTER EXPENSE OFFSET.....    8,797,377
                                                -----------
      NET INVESTMENT INCOME...................   49,272,443
  NET REALIZED GAIN...........................       67,452
                                                -----------
      NET INCREASE............................  $49,339,895
                                                -----------
                                                -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income........................................................   $    49,272,443    $    45,957,679
    Net realized gain............................................................            67,452          --
                                                                                   -----------------  -----------------
        Net increase.............................................................        49,339,895         45,957,679
 
    Dividends from net investment income.........................................       (49,272,477)       (45,956,910)
    Net increase from transactions in shares of beneficial interest..............        42,488,823         83,029,307
                                                                                   -----------------  -----------------
        Total increase...........................................................        42,556,241         83,030,076
NET ASSETS:
  Beginning of period............................................................     1,499,330,888      1,416,300,812
                                                                                   -----------------  -----------------
  END OF PERIOD (including undistributed net investment income of $1,091 and
   $1,125, respectively).........................................................   $ 1,541,887,129    $ 1,499,330,888
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       13
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION AND  ACCOUNTING POLICIES--Active  Assets Tax-Free  Trust (the
"Trust") is registered under the Investment Company Act of 1940, as amended (the
"Act"), as a  diversified, open-end management  investment company. The  Trust's
investment  objective is to provide a high level of daily income which is exempt
from federal income tax  consistent with stability  of principal and  liquidity.
The  Trust was organized as a Massachusetts business trust on March 30, 1981 and
commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that affect  the reported  amounts and  disclosures. Actual  results
could  differ from  those estimates. The  following is a  summary of significant
accounting policies:
 
    A.  VALUATION OF INVESTMENTS--Portfolio  securities are valued at  amortized
    cost, which approximates market value.
 
    B.   ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for on
    the trade date (date the order to  buy or sell is executed). Realized  gains
    and  losses on security  transactions are determined  by the identified cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.  FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with  the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies  and to distribute all of its taxable and nontaxable income to its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.   INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment  Management
Agreement  with Dean  Witter InterCapital  Inc. (the  "Investment Manager"), the
Trust pays the Investment  Manager a management fee,  accrued daily and  payable
monthly,  by applying the following annual rates  to the net assets of the Trust
determined as of the close of each  business day: 0.50% to the portion of  daily
net assets not exceeding $500 million; 0.425% to the portion of daily net assets
exceeding  $500 million but not exceeding $750 million; 0.375% to the portion of
daily net assets exceeding $750 million  but not exceeding $1 billion; 0.35%  to
the  portion of  daily net  assets exceeding $1  billion but  not exceeding $1.5
billion; 0.325% to the  portion of daily net  assets exceeding $1.5 billion  but
not  exceeding $2 billion; 0.30% to the portion of daily net assets exceeding $2
billion but  not exceeding  $2.5 billion;  0.275% to  the portion  of daily  net
assets  exceeding $2.5 billion  but not exceeding  $3 billion; and  0.25% to the
portion of daily net assets exceeding $3 billion.
 
    Under the  terms of  the  Agreement, in  addition  to managing  the  Trust's
investments,  the Investment Manager maintains certain  of the Trust's books and
records and furnishes, at its own expense, office space, facilities,  equipment,
clerical,  bookkeeping and certain  legal services and pays  the salaries of all
personnel, including officers of the Trust  who are employees of the  Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.   PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"), an
affiliate of the Investment  Manager, is the distributor  of the Trust's  shares
and,  in accordance with  a Plan of  Distribution (the "Plan")  pursuant to Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under the Plan,  the Distributor bears  the expense of  all promotional  and
distribution related activities on behalf of the Trust, except for expenses that
the   Trustees  determine  to  reimburse,  as  described  below.  The  following
activities  and  services  may  be   provided  by  the  Distributor  and   other
broker-dealers under the
 
                                       14
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
Plan:   (1)  compensation  to,  and  expenses  of,  the  Distributor  and  other
broker-dealers; (2) sales incentives and bonuses to sales representatives and to
marketing personnel in connection  with promoting sales  of the Trust's  shares;
(3)  expenses incurred in connection with promoting sales of the Trust's shares;
(4) preparing and distributing sales  literature; and (5) providing  advertising
and  promotional activities, including direct  mail solicitation and television,
radio, newspaper, magazine and other media advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average daily net assets. For the year ended June 30, 1996, the distribution fee
was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases and proceeds  from sales/maturities  of portfolio  securities for  the
year   ended  June  30,  1996   aggregated  $3,045,910,870  and  $2,956,347,425,
respectively.
 
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $24,000.
 
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent  Trustees  of  the  Trust  who  will  have  served as
independent Trustees for at least five years at the time of retirement. Benefits
under this plan are based on years  of service and compensation during the  last
five years of service. Aggregate pension costs for the year ended June 30, 1996,
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $1,238. At  June 30,  1996, the  Trust had  an accrued  pension liability  of
$48,883  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     5,666,091,760      5,690,475,533
Shares issued in reinvestment of dividends.......................................        49,272,477         45,956,910
                                                                                   -----------------  -----------------
                                                                                      5,715,364,237      5,736,432,443
Shares repurchased...............................................................    (5,672,875,414)    (5,653,403,136)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        42,488,823         83,029,307
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
   
6.   FEDERAL INCOME TAX  STATUS--During the year ended  June 30, 1996, the Trust
utilized all of its net capital loss carrryovers of approximately $59,000.
    
 
   
7.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
    
 
                                       15
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            SHORT-TERM VARIABLE RATE MUNICIPAL OBLIGATIONS (77.4%)
            ARIZONA
$   6,500   Maricopa County, Arizona Public Service Co 1994 Ser F.......          3.70%   07/01/96     $     6,500,000
            ARKANSAS
   20,000   Crossett, Georgia Pacific Corp Ser 1984.....................          3.25    07/08/96          20,000,000
            CALIFORNIA
            California Pollution Control Financing Authority,
   14,000     Pacific Gas & Electric Co Ser 1996 F......................          3.40    07/01/96          14,000,000
    5,900     Southern California Edison Co 1986 Ser A..................          3.45    07/01/96           5,900,000
   25,000   Riverside County, 1996-97 Ser B TRANs (WI)..................          3.00    07/08/96          25,000,000
            COLORADO
   11,500   Colorado Health Facilities Authority, Kaiser Permanente 1994
              Ser A.....................................................          3.40    07/08/96          11,500,000
            CONNECTICUT
   38,000   Connecticut Development Authority, Connecticut Light & Power
              Co
              1993 A Ser................................................          3.35    07/01/96          38,000,000
            Connecticut Special Assessment,
   30,000     Unemployment Compensation 1993 Ser C (FGIC)...............          3.90    07/01/96          30,000,000
   30,000     Unemployment Compensation 1993 Ser C (FGIC)...............          3.90    07/01/97          30,000,000
            FLORIDA
   15,000   Dade County, Water & Sewer Ser 1994 (FGIC)..................          3.30    07/08/96          15,000,000
            Dade County Industrial Development Authority,
   22,700     Dolphins Stadium Ser 1985 B & C...........................          3.35    07/08/96          22,700,000
    7,700     Florida Power & Light Co Ser 1993.........................          3.60    07/01/96           7,700,000
   11,200   Jacksonville Health Facilities Authority, Baptist Medical
              Center Ser 1993 (MBIA)....................................          3.65    07/01/96          11,200,000
    5,000   Orange County Housing Finance Authority, Single Family Ser
              1996 B (AMT)..............................................          3.65    04/01/97           5,000,000
   32,600   Volusia County Health Facilities Authority, Pooled Ser 1985
              (FGIC)....................................................          3.70    07/08/96          32,600,000
            GEORGIA
   10,000   Albany-Dougherty County Hospital Authority, Phoebe-Putney
              Memorial Hospital Ser 1991 (AMBAC)........................          3.40    07/08/96          10,000,000
   16,102   Georgia Municipal Association, Pool Ser 1990 COPs (MBIA)....          3.30    07/08/96          16,101,957
            HAWAII
            Hawaii Department of Budget & Finance,
    5,000     Kaiser Permanente Semiannual Tender Ser 1984 B............          3.20    09/01/96           5,000,000
   22,100     Queens Medical Center Ser 1985 B (FGIC)...................          3.10    07/08/96          22,100,000
            IDAHO
            Idaho Health Facilities Authority,
   20,000     Pooled Ser 1985...........................................          3.40    07/08/96          20,000,000
   12,910     St Luke's Regional Medical Center Ser 1995................          3.65    07/01/96          12,910,000
            ILLINOIS
            Chicago,
   24,900     Chicago O'Hare Int'l Airport 2nd Lien 1994 Ser B (AMT)....          3.50    07/08/96          24,900,000
   25,000     Tender Notes Ser 1995 A...................................          3.65    10/31/96          25,000,000
</TABLE>
    
 
                                       16
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
$   5,900   Illinois Development Finance Authority, Palos Community
              Hospital Ser 1994.........................................          3.30%   07/08/96     $     5,900,000
            Illinois Health Facilities Authority,
    9,000     Gottlieb Health Resources Inc Ser 1990....................          3.35    07/08/96           9,000,000
   19,600     Highland Park Hospital Ser 1991 A (FGIC)..................          3.40    07/08/96          19,600,000
   22,500     Lutheran General Health Care System Ser 1985 B............          3.60    07/01/96          22,500,000
   12,100     Northwestern Memorial Hospital Ser 1995...................          3.65    07/01/96          12,100,000
   10,000     Parkside Development Corp Ser 1991........................          3.45    07/08/96          10,000,000
    3,640   Illinois Housing Development Authority, Homeowner Mtg 1995
              Subser E-2 (AMT)..........................................          3.75    09/03/96           3,640,000
            INDIANA
   17,000   Indiana Hospital Equipment Financing Authority, Ser 1985
              (MBIA)....................................................          3.55    07/08/96          17,000,000
            Petersburg,
    8,400     Indianapolis Power & Light Co Ser 1995 B (AMBAC)..........          3.30    07/08/96           8,400,000
    5,000     Indianapolis Power & Light Co Ser 1994 A (AMT)............          3.35    07/08/96           5,000,000
    5,000   Purdue University, Student Fee Ser 1995 K...................          3.30    07/08/96           5,000,000
            KENTUCKY
    7,000   Jamestown, Union Underwear Co...............................          3.50    07/08/96           7,000,000
            LOUISIANA
   30,000   Louisiana Offshore Terminal Authority, LOOP Inc 1992 Ser
              A.........................................................          3.40    07/08/96          30,000,000
   23,200   New Orleans Aviation Board, Ser 1993 B (MBIA)...............          3.25    07/08/96          23,200,000
            MASSACHUSETTS
   15,000   Massachusetts Bay Transportation Authority, 1984 Ser A......          3.05    09/01/96          15,000,000
   29,500   Massachusetts Health & Educational Facilities Authority,
              Harvard University Ser 1985 I.............................          3.05    07/08/96          29,500,000
    6,100   Massachusetts Municipal Wholesale Electric Company, Power
              Supply 1994 Ser C.........................................          3.05    07/08/96           6,100,000
   14,800   Massachusetts Port Authority, Refg Ser 1995 A...............          3.50    07/01/96          14,800,000
            MICHIGAN
    3,000   Delta County Economic Development Corporation, Mead-Escanaba
              Paper Co Ser 1985 E.......................................          3.60    07/01/96           3,000,000
            MINNESOTA
    2,200   Beltrami County, Environmental Northwood Panelboard Co Ser
              1991......................................................          3.60    07/01/96           2,200,000
    8,500   Minneapolis & St Paul Housing & Redevelopment Authority,
              Childrens Health Care Ser 1995 B (CGIC)...................          3.75    07/01/96           8,500,000
   10,500   University of Minnesota Regents, Ser 1985 F.................          3.25    08/01/96          10,500,000
            MISSISSIPPI
    7,000   Jackson County, Chevron USA Inc Ser 1993....................          3.55    07/01/96           7,000,000
    5,500   Mississippi Business Finance Corporation, Mississippi Power
              Co (AMT)..................................................          3.75    07/01/96           5,500,000
            MISSOURI
   20,000   Missouri Health & Educational Facilities Authority, Sisters
              of Mercy Health System St Louis Inc Ser 1989 A............          3.35    07/01/96          20,000,000
            NEBRASKA
            Nebraska Higher Education Loan Program Inc,
   10,000     1985 Ser E (MBIA).........................................          3.40    07/08/96          10,000,000
    8,600     1986 Ser C (AMT)..........................................          3.50    07/08/96           8,600,000
            NEW HAMPSHIRE
    2,500   New Hampshire Higher Educational & Health Facilities
              Authority, Dartmouth Education Loan Corp Ser 1993 (AMT)...          3.90    06/01/97           2,500,000
</TABLE>
    
 
   
                                       17
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            NEW JERSEY
$  11,000   New Jersey Economic Development Authority, New Jersey
              Natural Gas Co Ser 1995 A (AMBAC).........................          3.50%   07/01/96     $    11,000,000
    8,000   New Jersey Turnpike Authority, Ser 1991 D (FGIC)............          3.00    07/08/96           8,000,000
    6,400   Union County Industrial Pollution Control Financing
              Authority, Exxon Corp.....................................          2.90    07/01/96           6,400,000
            NEW MEXICO
   39,200   Albuquerque, Airport Sub Lien Ser 1995 (AMBAC)..............          3.30    07/08/96          39,200,000
            NEW YORK
   14,800   New York Local Government Assistance Corporation, Ser 1995
              B.........................................................          3.10    07/08/96          14,800,000
    1,000   St Lawrence County Industrial Development Agency, Reynolds
              Metals Co Ser 1995 (AMT)..................................          3.35    07/08/96           1,000,000
            NORTH CAROLINA
    9,400   Craven County Industrial Facilities & Pollution Control
              Financing Authority, Craven County Wood Energy Ltd 1989
              Ser C (AMT)...............................................          3.75    07/01/96           9,400,000
    9,800   Durham, Ser 1993 A COPs.....................................          3.20    07/08/96           9,800,000
   26,985   North Carolina Medical Care Commission, Duke University
              Hospital Ser 1985 B & C...................................          3.25    07/08/96          26,985,000
   21,700   Person County Industrial Facilities & Pollution Control
              Financing Authority, Carolina Power & Light Co Ser 1992
              A.........................................................          3.25    07/08/96          21,700,000
            OHIO
    1,300   Dayton, Emery Air Freight Co 1988 Ser C.....................          3.70    07/01/96           1,300,000
    5,600   Ohio Air Quality Development Authority, Cincinnati Gas &
              Electric Co Ser A.........................................          3.50    07/01/96           5,600,000
   12,000   Ohio Housing Financing Agency, Residential Mtg 1996 Ser A-3
              (AMT).....................................................          3.40    03/03/97          12,000,000
            OKLAHOMA
            Oklahoma Water Resources Board,
   18,750     State Loan Prog Ser 1994 A................................          3.25    09/01/96          18,750,000
   10,000     State Loan Prog Ser 1995..................................          3.10    09/03/96          10,000,000
            PENNSYLVANIA
   10,000   Allegheny County Hospital Development Authority, Health
              Education & Research Corp Ser 1988 B......................          3.30    07/08/96          10,000,000
   10,000   Beaver County Industrial Development Authority, Toledo
              Edison Co 1992 Ser E......................................          3.65    07/05/96          10,000,000
    6,800   Delaware County Industrial Development Authority, United
              Parcel Service of America Inc Ser 1995....................          3.60    07/01/96           6,800,000
   10,500   Pennsylvania Energy Development Authority, Clarion Co Piney
              Creek Ser A (AMT).........................................          3.55    07/08/96          10,500,000
            Pennsylvania Higher Education Facilities Authority,
    7,000     Temple University Ser 1984-1..............................          3.60    07/08/96           7,000,000
    5,000     Thomas Jefferson University Ser 1992 C....................          3.25    08/26/96           5,000,000
   10,000   Philadelphia Hospitals & Higher Educational Facilities
              Authority, Children's Hospital of Philadelphia 1996 Ser
              A.........................................................          3.60    07/01/96          10,000,000
    8,300   Washington County Authority, Pooled Ser 1985 A-1 Subser B...          3.25    07/08/96           8,300,000
            SOUTH CAROLINA
    5,905   York County, Saluda River Electric Coop Inc Ser 1984 E-2
              (NRU-CFC Gtd).............................................          3.10    08/15/96           5,905,000
            TENNESSEE
    7,704   Clarksville Public Building Authority Ser 1990 (MBIA).......          3.30    07/08/96           7,704,000
    7,900   Memphis, Airport Refg Ser 1995 B............................          3.50    07/08/96           7,900,000
   20,000   Volunteer State Student Funding, Ser A-3 (AMT)..............          3.60    07/08/96          20,000,000
</TABLE>
    
 
   
                                       18
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
PRINCIPAL
AMOUNT (IN                                                                   CURRENT      DEMAND
THOUSANDS)                                                                    RATE+        DATE*            VALUE
- ----------                                                                   -------      -------      ---------------
<C>         <S>                                                              <C>          <C>          <C>
            TEXAS
$   8,400   Gulf Coast Waste Disposal Authority, Amoco Oil Co Ser
              1992......................................................          3.50%   07/01/96     $     8,400,000
   28,000   Harris County, Toll Road Unlimited Tax Sub Lien Ser 1994 B &
              C.........................................................          3.40    07/08/96          28,000,000
   10,000   Hockley County Industrial Development Corporation, Amoco Oil
              Co Ser 1985...............................................          3.60    11/01/96          10,000,000
    6,500   Sabine River Authority, Texas Utilities Co Ser 1996 A
              (AMBAC)...................................................          3.60    07/01/96           6,500,000
   15,000   Texas, Veterans' Housing Assistance Fund I Ser 1995.........          3.30    07/08/96          15,000,000
            UTAH
   25,000   Intermountain Power Agency, 1985 Ser E......................          3.35    09/15/96          25,000,000
            VIRGINIA
   15,000   Virginia Housing Development Authority, 1995 Subser D STEM
              IV........................................................          3.35    07/16/96          15,000,000
            WASHINGTON
    5,800   Seattle, Municipal Light & Power Ser 1993...................          3.40    07/08/96           5,800,000
            WISCONSIN
    9,500   Brokaw, Wausau Paper Mills Co Ser 1995 (AMT)................          3.60    07/08/96           9,500,000
   10,000   Wisconsin Health Facilities Authority, Franciscan Health
              Care Inc Ser 1985 A-1.....................................          3.45    07/08/96          10,000,000
            WYOMING
   10,200   Lincoln County, Exxon Corp Ser 1987 A (AMT).................          3.70    07/01/96          10,200,000
    8,250   Sublette County, Exxon Corp Ser 1987 A (AMT)................          3.65    07/01/96           8,250,000
    4,100   Sweetwater County, PacifiCorp Ser 1994 (AMBAC)..............          3.70    07/01/96           4,100,000
                                                                                                       ---------------
            TOTAL SHORT-TERM VARIABLE RATE MUNICIPAL OBLIGATIONS
              (AMORTIZED COST $1,193,445,957)....................................................        1,193,445,957
                                                                                                       ---------------
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
                                                                                                      ON DATE
                                                                             COUPON     MATURITY        OF
                                                                              RATE        DATE        PURCHASE
                                                                          ------------  ---------     -------
<C>         <S>                                                           <C>           <C>           <C>          <C>
            TAX-EXEMPT COMMERCIAL PAPER (19.7%)
            FLORIDA
    7,000   Florida Local Government Finance Commission, Ser 1991.......        3.60%   08/28/96           3.60%         7,000,000
    8,690   Jacksonville, Florida Power & Light Co Ser 1994.............        3.60    11/15/96           3.60          8,690,000
   10,700   Jacksonville Electric Authority, Ser A......................        3.65    10/24/96           3.65         10,700,000
            Palm Beach County Health Facilities Authority,
    6,500     Pooled Hospital Ser 1985 (MBIA)...........................        3.55    07/11/96           3.55          6,500,000
    5,500     Pooled Hospital Ser 1985 (MBIA)...........................        3.60    07/25/96           3.60          5,500,000
   12,425   Sunshine State Governmental Financing Commission, Ser 1994
              B.........................................................        3.30    07/30/96           3.30         12,425,000
            GEORGIA
   10,400   Burke County Development Authority, Oglethorpe Power Corp
              Ser 1992 A................................................        3.55    11/07/96           3.55         10,400,000
    8,000   Georgia Municipal Gas Authority, Transco Portfolio 1 Ser
              A.........................................................        3.35    08/27/96           3.35          8,000,000
            HAWAII
    4,000   Hawaii Department of Budget & Finance, Citizens Utilities Co
              1988 Ser B (AMT)..........................................        3.70    08/20/96           3.70          4,000,000
            INDIANA
   10,000   Indianapolis, Citizens Gas & Coke Utility...................        3.55    09/09/96           3.55         10,000,000
            MARYLAND
   12,000   Baltimore County, Ser 1995 BANs.............................        3.45    09/11/96           3.45         12,000,000
</TABLE>
    
 
                                       19
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
PRINCIPAL                                                                                             ON DATE
AMOUNT (IN                                                                   COUPON     MATURITY        OF
THOUSANDS)                                                                    RATE        DATE        PURCHASE          VALUE
- ----------                                                                ------------  ---------     -------      ---------------
            MASSACHUSETTS
<C>         <S>                                                           <C>           <C>           <C>          <C>
$  10,000   Massachusetts Health & Educational Facilities Authority,
              Boston University Ser H...................................        3.65%   08/22/96           3.65%   $    10,000,000
            Massachusetts Water Resources Authority,
   10,000     Ser 1994..................................................        3.30    07/31/96           3.30         10,000,000
   10,000     Ser 1994..................................................        3.30    08/14/96           3.30         10,000,000
            MINNESOTA
   10,000   Southern Minnesota Municipal Power Agency, Ser B............        3.60    10/17/96           3.60         10,000,000
            MISSOURI
   15,145   Missouri Environmental Improvement & Energy Resources
              Authority, Union Electric Co Ser 1985 A...................        3.50    07/15/96           3.50         15,145,000
            NEBRASKA
   15,000   Nebraska Public Power District, Ser B Notes.................        3.65    09/12/96           3.65         15,000,000
            NEW HAMPSHIRE
   10,000   New Hampshire Business Finance Authority, New England Power
              Co 1990 Ser A (AMT).......................................        3.80    08/08/96           3.80         10,000,000
            NORTH CAROLINA
            North Carolina Municipal Power Agency 1,
   11,510     Catawba Elec Ser A........................................        3.60    10/11/96           3.60         11,510,000
   10,000     Catawba Elec Ser A........................................        3.60    11/12/96           3.60         10,000,000
            SOUTH CAROLINA
            South Carolina Public Service Authority,
   10,000     Promissory Notes..........................................        3.60    10/10/96           3.60         10,000,000
   10,542     Promissory Notes..........................................        3.60    10/22/96           3.60         10,542,000
   10,000     Promissory Notes..........................................        3.60    10/29/96           3.60         10,000,000
            TEXAS
            Houston,
   16,000     1993 Ser A................................................        3.43    07/10/96           3.43         16,000,000
    4,000     1993 Ser A................................................        3.50    10/30/96           3.50          4,000,000
   10,900     1993 Ser A................................................        3.50    10/30/96           3.50         10,900,000
   10,000   Houston, Water & Sewer Ser A................................        3.50    10/23/96           3.50         10,000,000
    9,400   San Antonio, Water Ser 1995.................................        3.60    10/18/96           3.60          9,400,000
   10,000   Texas Municipal Power Agency................................        3.50    11/13/96           3.50         10,000,000
            WASHINGTON
    8,000   Seattle, Municipal Light & Power Ser 1990...................        3.65    10/15/96           3.65          8,000,000
            WYOMING
    7,500   Converse County, PacifiCorp Ser 1992........................        3.55    07/31/96           3.55          7,500,000
                                                                                                                   ---------------
            TOTAL TAX-EXEMPT COMMERCIAL PAPER
              (AMORTIZED COST $303,212,000)..................................................................          303,212,000
                                                                                                                   ---------------
 
            SHORT-TERM MUNICIPAL NOTES (9.5%)
            COLORADO
   15,000   Colorado, Ser 1996 A TRANs, dtd 07/01/96 (WI)...............        4.50    06/27/97           3.86         15,091,350
            IDAHO
   23,000   Idaho, Ser 1996 TANs, dtd 07/02/96 (WI).....................        4.50    06/30/97           3.90         23,132,020
            INDIANA
   10,000   Indiana Bond Bank Advance Funding Notes Ser 1996 A-2, dtd
              02/01/96..................................................        4.25    01/09/97           3.50         10,038,517
</TABLE>
    
 
   
                                       20
    
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
ACTIVE ASSETS TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
    
   
<TABLE>
<CAPTION>
                                                                                                       YIELD
                                                                                                        TO
                                                                                                      MATURITY
PRINCIPAL                                                                                             ON DATE
AMOUNT (IN                                                                   COUPON     MATURITY        OF
THOUSANDS)                                                                    RATE        DATE        PURCHASE          VALUE
- ----------                                                                ------------  ---------     -------      ---------------
            IOWA
<C>         <S>                                                           <C>           <C>           <C>          <C>
$  30,000   Iowa School Corporations, Warrant Certificates Ser 1996-97
              (FSA), dtd 06/27/96.......................................        4.75%   06/27/97           3.95%   $    30,229,436
            MASSACHUSETTS
   15,000   Massachusetts, 1996 Ser A Notes, dtd 06/11/96...............        4.25    06/10/97           3.90         15,047,754
            MICHIGAN
            Michigan Municipal Bond Authority,
   23,000     Ser 1995 B Notes, dtd 07/03/95............................        4.50    07/03/96           3.80         23,001,694
   20,000     Ser 1996 A Notes, dtd 07/03/96 (WI).......................        4.50    07/03/97           3.90         20,115,400
   10,000   Michigan, Notes dtd 02/20/96................................        4.00    09/30/96           3.00         10,025,022
                                                                                                                   ---------------
            TOTAL SHORT-TERM MUNICIPAL NOTES
              (AMORTIZED COST $146,681,193)..................................................................          146,681,193
                                                                                                                   ---------------
</TABLE>
    
 
   
<TABLE>
<C>          <S>                                                                 <C>    <C>
             TOTAL INVESTMENTS (AMORTIZED COST $1,643,339,150) (A).......        106.6%  1,643,339,150
             LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS..............        (6.6 )   (101,452,021)
                                                                                 -----  --------------
             NET ASSETS..................................................        100.0% $1,541,887,129
                                                                                 -----  --------------
                                                                                 -----  --------------
</TABLE>
    
 
- ------------
 
   
      AMT        ALTERNATIVE MINIMUM TAX.
     BANS        BOND ANTICIPATION NOTES.
     COPS        CERTIFICATES OF PARTICIPATION.
     TANS        TAX ANTICIPATION NOTES.
     TRANS       TAX AND REVENUE ANTICIPATION NOTES.
      WI         SECURITY PURCHASED ON A WHEN ISSUED BASIS.
       +         RATE SHOWN IS THE RATE IN EFFECT AT JUNE 30, 1996.
                 DATE IN WHICH THE PRINCIPAL AMOUNT CAN BE
       *         RECOVERED THROUGH DEMAND.
      (A)        COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
BOND INSURANCE:
     AMBAC       AMBAC INDEMNITY CORPORATION.
     CGIC        CAPITAL GUARANTY INSURANCE COMPANY.
     FGIC        FINANCIAL GUARANTY INSURANCE COMPANY.
      FSA        FINANCIAL SECURITY ASSURANCE INC.
     MBIA        MUNICIPAL BOND INVESTORS ASSURANCE CORPORATION.
 
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       21
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS TAX-FREE TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
To the Shareholders and Trustees of Active Assets Tax-Free Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material respects, the  financial position of  Active Assets Tax-Free Trust
(the "Trust") at June 30, 1996, the results of its operations for the year  then
ended,  the changes in  its net assets for  each of the two  years in the period
then ended and the financial highlights for each of the ten years in the  period
then  ended, in conformity with  generally accepted accounting principles. These
financial  statements  and  financial  highlights  (hereafter  referred  to   as
"financial  statements") are the  responsibility of the  Trust's management; our
responsibility is to express an opinion  on these financial statements based  on
our  audits. We conducted our audits of these financial statements in accordance
with generally  accepted  auditing standards  which  require that  we  plan  and
perform  the audit  to obtain reasonable  assurance about  whether the financial
statements are free of material misstatement. An audit includes examining, on  a
test  basis, evidence  supporting the amounts  and disclosures  in the financial
statements, assessing the accounting  principles used and significant  estimates
made by management, and evaluating the overall financial statement presentation.
We  believe that our  audits, which included confirmation  of securities at June
30, 1996 by correspondence with the custodian and brokers, provide a  reasonable
basis for the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
   
                      1996 FEDERAL TAX NOTICE (UNAUDITED)
During  the year ended June 30, 1996,  the Trust paid to shareholders $0.031 per
share from  net  investment  income.  All of  the  Trust's  dividends  from  net
investment  income were exempt interest  dividends, excludable from gross income
for Federal income tax purposes.
    
 
                                       22
                          ACTIVE ASSETS TAX-FREE TRUST
<PAGE>
   
STATEMENTS OF ADDITIONAL INFORMATION
AUGUST 22, 1996                                                           [LOGO]
    
 
- --------------------------------------------------------------------------------
 
    Active  Assets Money Trust (the "Money Trust"  or the "Trust") is a no-load,
diversified open-end management investment  company whose investment  objectives
are  high current income, preservation of capital and liquidity. The Money Trust
seeks to  achieve its  objectives by  investing in  a diversified  portfolio  of
short-term money market instruments.
 
    Active  Assets Tax-Free  Trust (the  "Tax-Free Trust"  or the  "Trust") is a
no-load, diversified  open-end management  investment company  whose  investment
objective  is to  provide as high  a level  of daily income  exempt from federal
personal income tax as is consistent with stability of principal and  liquidity.
The Tax-Free Trust seeks to achieve its objective by investing primarily in high
quality tax-exempt securities with short-term maturities.
 
    Active  Assets California Tax-Free Trust (the "California Tax-Free Trust" or
the "Trust") is  a no-load, diversified  open-end management investment  company
whose  investment objective is to provide as high a level of daily income exempt
from federal and California personal income tax as is consistent with  stability
of  principal and liquidity. The California  Tax-Free Trust seeks to achieve its
objective by  investing primarily  in high  quality tax-exempt  securities  with
short-term maturities.
 
    Active Assets Government Securities Trust (the "Government Securities Trust"
or the "Trust") is a no-load, diversified open-end management investment company
whose investment objectives are high current income, preservation of capital and
liquidity.  The Government  Securities Trust seeks  to achieve  its objective by
investing in U.S. Government securities, including a variety of securities which
are issued  or guaranteed  by  the United  States  Government, its  agencies  or
instrumentalities.
 
   
    Prospectuses  for  the  Money  Trust,  the  Tax-Free  Trust,  the California
Tax-Free Trust and the Government Securities  Trust, all dated August 22,  1996,
which  provide the basic information you should  know before investing in any of
the aforementioned Trusts, may be obtained without charge from any of the Trusts
at the address or telephone number listed below. These Statements of  Additional
Information  are not Prospectuses.  They contain information  in addition to and
more detailed than  that set  forth in the  Prospectuses. They  are intended  to
provide  additional information regarding  the activities and  operations of the
Trusts, and should be read in conjunction with the Prospectuses. They should  be
read  with the information appearing  in the Appendix hereto  which is a part of
these Statements of Additional Information.
    
 
Active Assets Money Trust
Active Assets Tax-Free Trust
Active Assets California Tax-Free Trust
Active Assets Government Securities Trust
 
Two World Trade Center
New York, New York 10048
(212) 392-2550
 
    The shares of the Money Trust,  the Tax-Free Trust, the California  Tax-Free
Trust  and the  Government Securities Trust  are offered to  participants in the
Active Assets Account program of Dean  Witter Reynolds Inc. ("Dean Witter").  In
addition,  shares of the  Trusts are offered  to investors maintaining brokerage
accounts with Dean Witter who are not subscribers to the Active Assets  program.
For  further information,  either consult  the Dean  Witter Client  Agreement or
consult your Dean Witter Account Executive.
 
Active Assets California Tax-Free Trust
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
TABLE OF CONTENTS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                                                     <C>
Investment Practices and Policies.....................................      3
 
Investment Restrictions...............................................      7
 
Special Considerations Relating to California Tax-Exempt Securities...      8
 
How Net Asset Value is Determined.....................................     11
 
Dividends, Distributions and Taxes....................................     13
 
Financial Statements..................................................     17
 
Report of Independent Accountants.....................................     22
 
APPENDIX
 
Investment Manager....................................................    A-1
 
Trustees and Officers.................................................    A-7
 
Portfolio Transactions and Brokerage..................................   A-15
 
General Information...................................................   A-16
 
Custodian and Transfer Agent..........................................   A-16
 
Independent Accountants...............................................   A-17
 
Reports to Shareholders...............................................   A-17
 
Legal Counsel.........................................................   A-17
 
Experts...............................................................   A-17
 
Registration Statement................................................   A-17
 
Information with Respect to Securities Ratings........................   A-17
</TABLE>
    
 
Active Assets California Tax-Free Trust   2
<PAGE>
INVESTMENT PRACTICES AND POLICIES
- --------------------------------------------------------------------------------
 
PORTFOLIO SECURITIES
 
    TAXABLE SECURITIES.  As discussed in the Prospectus, the Trust may invest up
to 20%  of its  total assets  in taxable  money market  instruments,  repurchase
agreements  and  non-California  tax-exempt securities.  Investments  in taxable
money market instruments would generally be made under any one of the  following
circumstances:  (a) pending  investment proceeds of  sale of Trust  shares or of
portfolio  securities;  (b)  pending   settlement  of  purchases  of   portfolio
securities; and (c) to maintain liquidity for the purpose of meeting anticipated
redemptions.  Only those non-California tax-exempt  securities which satisfy the
standards established for California tax-exempt  securities may be purchased  by
the Fund.
 
    In  addition, the Trust  may temporarily invest  more than 20%  of its total
assets  in  non-California  tax-exempt  securities  and  taxable  money   market
instruments,  or  in short-term  tax-exempt  securities subject  to  the federal
alternative minimum tax for individual  shareholders, to maintain a  "defensive"
posture when, in the opinion of the Investment Manager, it is advisable to do so
because  of market conditions. The types  of taxable money market instruments in
which the Trust may invest are limited to the following short-term  fixed-income
securities  (maturing  in one  year  or less  from  the time  of  purchase): (i)
obligations of the United States Government, its agencies, instrumentalities  or
authorities; (ii) commercial paper rated P-1 by Moody's Investors Services, Inc.
("Moody's")  or A-1 by Standard & Poor's Corporation ("S&P"); (iii) certificates
of deposit  of domestic  banks  with assets  of $1  billion  or more;  and  (iv)
repurchase agreements with respect to portfolio securities.
 
    TAX-EXEMPT  SECURITIES.  As discussed in the Prospectus, at least 80% of the
Trust's total  assets  will  be invested  in  California  tax-exempt  securities
(California Municipal Bonds, California Municipal Notes and California Municipal
Commercial  Paper). In regard  to the Moody's  and S&P ratings  discussed in the
Prospectus, it should  be noted  that the ratings  represent the  organizations'
opinions  as to the quality  of the securities which  they undertake to rate and
the ratings are general and not absolute standards of quality. For a description
of Municipal  Bond, Municipal  Note and  Municipal Commercial  Paper ratings  by
Moody's  and S&P,  see "Information with  Respect to Securities  Ratings" in the
Appendix to this Statement of Additional Information.
 
    The percentage and rating limitations discussed above and in the  Prospectus
apply  at the  time of acquisition  of a  security based upon  the last previous
determination of  the Trust's  net asset  value; any  subsequent change  in  any
ratings  by  a rating  service or  change in  percentages resulting  from market
fluctuations or other changes  in total assets will  not require elimination  of
any security from the Fund's portfolio.
 
    The  payment  of  principal and  interest  by issuers  of  certain Municipal
Obligations purchased by  the Trust may  be guaranteed by  letters of credit  or
other  credit facilities offered by banks  or other financial institutions. Such
guarantees will  be considered  in determining  whether a  Municipal  Obligation
meets  the Trust's investment quality requirements. In addition, some issues may
contain provisions which permit the Trust to demand from the issuer repayment of
principal at some specified period(s) prior to maturity.
 
    MUNICIPAL BONDS.   Municipal Bonds, as  referred to in  the Prospectus,  are
debt  obligations of a state, its  cities, municipalities and municipal agencies
(all of which  are generally  referred to as  "municipalities") which  generally
have  a maturity at the time of issue of one year or more, and the interest from
which is, in the  opinion of bond  counsel, exempt from  federal income tax.  In
addition  to these  requirements, the  interest from  California Municipal Bonds
must be, in the opinion of bond counsel, exempt from California personal  income
tax.  They  are issued  to  raise funds  for  various public  purposes,  such as
construction of  a  wide  range  of public  facilities,  to  refund  outstanding
obligations  and to obtain  funds for general  operating expenses or  to loan to
other  public  institutions  and  facilities.  In  addition,  certain  types  of
industrial  development bonds  and pollution control  bonds are issued  by or on
behalf of public authorities to  provide funding for various privately  operated
facilities.
 
Active Assets California Tax-Free Trust   3
<PAGE>
    MUNICIPAL   NOTES.     Municipal   Notes   are  short-term   obligations  of
municipalities, generally with a maturity at  the time of issuance ranging  from
six  months to three years,  the interest from which is,  in the opinion of bond
counsel, exempt from federal income tax. In addition to those requirements,  the
interest  from  California  Municipal Notes  must  be,  in the  opinion  of bond
counsel, exempt  from California  personal income  tax. The  principal types  of
Municipal Notes include tax anticipation notes, bond anticipation notes, revenue
anticipation  notes  and  project  notes,  although  there  are  other  types of
Municipal Notes in  which the Trust  may invest. Notes  sold in anticipation  of
collection  of  taxes, a  bond sale  or  receipt of  other revenues  are usually
general obligations of  the issuing  municipality or agency.  Project Notes  are
issued  by local agencies and are guaranteed  by the United States Department of
Housing and Urban  Development. Such  notes are secured  by the  full faith  and
credit of the United States Government.
 
    MUNICIPAL COMMERCIAL PAPER.  Municipal Commercial Paper refers to short-term
obligations of municipalities the interest from which is, in the opinion of bond
counsel,  exempt from federal income tax. In addition to those requirements, the
interest from  California Commercial  Paper  must be,  in  the opinion  of  bond
counsel,  exempt from  California personal  income tax.  It may  be issued  at a
discount and is sometimes  referred to as  Short-Term Discount Notes.  Municipal
Commercial  Paper is likely to be used to meet seasonal working capital needs of
a municipality or  interim construction financing  and to be  paid from  general
revenues  of the municipality  or refinanced with long-term  debt. In most cases
Municipal Commercial Paper is backed  by letters of credit, lending  agreements,
note  repurchase agreements or other credit facility agreements offered by banks
or other institutions.
 
    The two principal classifications of  Municipal Bonds, Notes and  Commercial
Paper  are "general obligation" and "revenue"  bonds, notes or commercial paper.
General obligation bonds, notes or commercial paper are secured by the  issuer's
pledge  of its faith, credit  and taxing power for  the payment of principal and
interest. Issuers of general obligation bonds, notes or commercial paper include
a state,  its counties,  cities,  towns and  other governmental  units.  Revenue
bonds,  notes or commercial paper  are payable from the  revenues derived from a
particular facility or  class of  facilities or,  in some  cases, from  specific
revenue  sources. Revenue bonds, notes or commercial paper are issued for a wide
variety of purposes, including the financing  of electric, gas, water and  sewer
systems and other public utilities; industrial development and pollution control
facilities;   single  and  multi-family  housing  units;  public  buildings  and
facilities; air and marine ports; transportation facilities such as toll  roads,
bridges and tunnels; and health and educational facilities such as hospitals and
dormitories.  They rely primarily on user fees to pay debt service, although the
principal revenue source is often  supplemented by additional security  features
which  are intended to enhance the creditworthiness of the issuer's obligations.
In some cases,  particularly with  respect to  revenue bonds  issued to  finance
housing  and  public buildings,  a  direct or  implied  "moral obligation"  of a
governmental unit may be pledged to the payment of debt service. In other cases,
a special tax or other charge may augment user fees.
 
    Issuers of these obligations  are subject to  the provisions of  bankruptcy,
insolvency  and other laws affecting the  rights and remedies of creditors, such
as the  Federal Bankruptcy  Act,  and laws,  if any,  which  may be  enacted  by
Congress  or any state extending the time  for payment of principal or interest,
or both, or imposing other constraints  upon enforcement of such obligations  or
upon  municipalities to  levy taxes.  There is  also the  possibility that  as a
result of litigation or other conditions the power or ability of any one or more
issuers to pay, when due, principal of and interest on its, or their,  Municipal
Bonds,  Municipal  Notes  and  Municipal  Commercial  Paper  may  be  materially
affected.
 
PORTFOLIO MANAGEMENT
 
    VARIABLE RATE AND FLOATING RATE OBLIGATIONS.   As stated in the  Prospectus,
the  Trust  may  invest  in  Municipal  Bonds  and  Municipal  Notes ("Municipal
Obligations")  of  the   type  called  "variable   rate"  and  "floating   rate"
obligations.
 
    The  interest rate payable on a  variable rate obligation is adjusted either
at predesignated periodic intervals and  on floating rate Municipal  Obligations
whenever  there is a change in the market rate of interest on which the interest
rate payable  is  based.  Other  features may  include  the  right  whereby  the
 
Active Assets California Tax-Free Trust   4
<PAGE>
Trust  may demand prepayment of the principal  amount of the obligation prior to
its stated maturity (a "demand feature") and  the right of the issuer to  prepay
the principal amount prior to maturity. The principal benefit of a variable rate
Municipal  Obligation is that the interest  rate adjustment minimizes changes in
the market value of the obligation. As  a result, the purchase of variable  rate
and  floating rate Municipal Obligations could  enhance the ability of the Trust
to maintain a  stable net asset  value per share  (see "How Net  Asset Value  is
Determined' in the Prospectus). The principal benefit to the Trust of purchasing
obligations  with a  demand feature  is that liquidity,  and the  ability of the
Trust to obtain repayment of the full principal amount of a Municipal Obligation
prior to maturity, is enhanced.
 
   
    WHEN-ISSUED AND DELAYED DELIVERY SECURITIES.   As stated in the  Prospectus,
the  Trust  may  purchase  tax-exempt securities  on  a  when-issued  or delayed
delivery basis. When such transactions are negotiated, the price is fixed at the
time of commitment,  but delivery and  payment can  take place a  month or  more
after  the date of the commitment. While the Trust will only purchase securities
on a when-issued or delayed delivery  basis with the intention of acquiring  the
securities,  the Trust may sell the securities before the settlement date, if it
is deemed advisable. The securities so  purchased or sold are subject to  market
fluctuation  and no interest accrues to the purchaser during this period. At the
time the Trust  makes the  commitment to purchase  a Municipal  Obligation on  a
when-issued  or  delayed  delivery basis,  it  will record  the  transaction and
thereafter  reflect  the  value,  each  day,  of  the  Municipal  Obligation  in
determining  its net  asset value.  The Trust  will also  establish a segregated
account with its custodian bank in which it will maintain liquid assets such  as
cash,   U.S.  government  securities  or   other  appropriate  high  grade  debt
obligations equal  in  value to  commitments  for such  when-issued  or  delayed
delivery securities.
    
 
    REPURCHASE  AGREEMENTS.  When cash may be  available for only a few days, it
may be invested by the Trust in repurchase agreements until such time as it  may
otherwise  be invested or used  for payments of obligations  of the Trust. These
agreements, which may  be viewed  as a  type of  secured lending  by the  Trust,
typically involve the acquisition by the Trust of debt securities from a selling
financial   institution  such  as  a  bank,  savings  and  loan  association  or
broker-dealer. The  agreement provides  that the  Trust will  sell back  to  the
institution,  and that the institution  will repurchase, the underlying security
("collateral"), which is held by the Trust's Custodian, at a specified price and
at a fixed time in  the future, which is usually  not more than seven days  from
the  date of purchase. The Trust will accrue interest from the institution until
the time when the repurchase  is to occur. Although such  date is deemed by  the
Trust  to be  the maturity  date of  a repurchase  agreement, the  maturities of
securities subject to repurchase  agreements are not subject  to any limits  and
may exceed one year.
 
   
    While repurchase agreements involve certain risks not associated with direct
investments  in  debt  securities,  the  Trust  follows  procedures  designed to
minimize such risks. These procedures include effecting repurchase  transactions
only  with large, well capitalized  and well established financial institutions,
whose financial condition will be continually monitored. In addition, the  value
of  the collateral underlying  the repurchase agreement will  always be at least
equal to the  resale price  which consists  of the  purchase price  paid to  the
seller of the securities plus the accrued resale premium which is defined as the
amount  specified in the  repurchase agreement or the  daily amortization of the
difference between the  purchase price  and the  resale price  specified in  the
repurchase  agreement. Such collateral will  consist entirely of securities that
are direct obligations  of, or  that are fully  guaranteed as  to principal  and
interest  by, the  United States or  any agency thereof,  and/or certificates of
deposit, bankers' acceptances  which are  eligible for acceptance  by a  Federal
Reserve Bank, and, if the seller is a bank, mortgage related securities (as such
term is defined in section 3(a)(41) of the Securities Exchange Act of 1934 that,
at  the time the repurchase agreement is  entered into, are rated in the highest
rating category  by  the Requisite  NRSROs.  Additionally, the  collateral  must
quality  the repurchase agreement  for preferential treatment  under the Federal
Deposit Insurance Act or the Federal Bankruptcy Code. In the event of a  default
or  bankruptcy  by  a selling  financial  institution,  the Trust  will  seek to
liquidate such  collateral.  However,  the  exercise of  the  Trust's  right  to
liquidate  such collateral  could involve  certain costs  or delays  and, to the
extent that  proceeds  from  any  sale  upon a  default  of  the  obligation  to
repurchase  were less than the repurchase price,  the Trust could suffer a loss.
It   is   the    current   policy   of    the   Trust   not    to   invest    in
    
 
Active Assets California Tax-Free Trust   5
<PAGE>
repurchase  agreements  that  do  not  mature  within  seven  days  if  any such
investment, together with any other illiquid asset held by the Trust, amount  to
more  than  10%  of its  total  assets.  The Trust's  investments  in repurchase
agreements may,  at times,  be substantial  when,  in the  view of  the  Trust's
investment manager, liquidity or other considerations warrant. The Trust has not
to  date and has no intention to enter into any repurchase agreements during the
coming fiscal year.
 
    PUT OPTIONS.  The Trust may  purchase securities together with the right  to
resell  them to the seller  at an agreed upon price  or yield within a specified
period prior to the maturity date of such securities. Such a right to resell  is
commonly  known as  a "put," and  the aggregate  price which the  Trust pays for
securities with puts may be higher than the price which otherwise would be  paid
for  the  securities.  Consistent  with the  Trust's  investment  objectives and
subject to the supervision of the Board of Trustees, the primary purpose of this
practice is to permit the Trust to be fully invested in securities the  interest
on  which  is exempt  from  Federal and  California  personal income  tax, while
preserving the necessary flexibility and  liquidity to purchase securities on  a
when-issued  basis, to  meet unusually  large redemptions  and to  purchase at a
later date securities other  than those subject to  the put. The Trust's  policy
is,  generally, to exercise the puts on their expiration date, when the exercise
price is higher than the current  market price for the related securities.  Puts
may  be exercised prior to  the expiration date in  order to fund obligations to
purchase other securities or to meet redemption requests. These obligations  may
arise  during periods  in which  proceeds from  sales of  Trust shares  and from
recent sales of portfolio securities  are insufficient to meet such  obligations
or when the funds available are otherwise allocated for investment. In addition,
puts may be exercised prior to their expiration date in the event the Investment
Manager  revises its  evaluation of  the creditworthiness  of the  issuer of the
underlying security.  In determining  whether to  exercise puts  prior to  their
expiration  date and in selecting which  puts to exercise in such circumstances,
the Investment  Manager  considers,  among  other things,  the  amount  of  cash
available  to the Trust, the expiration dates  of the available puts, any future
commitments for securities purchases, the  yield, quality and maturity dates  of
the   underlying  securities,  alternative   investment  opportunities  and  the
desirability of retaining the underlying securities in the Trust's portfolio.
 
    The Trust values  securities which are  subject to puts  at their  amortized
cost and values the put, apart from the security, at zero. Thus, the cost of the
put  will be carried on the Trust's books as an unrealized loss from the date of
acquisition and will  be reflected  in realized  gain or  loss when  the put  is
exercised  or expires. Since the value of the put is dependent on the ability of
the put writer to meet  its obligation to repurchase,  the Trust's policy is  to
enter  into  put transactions  only with  municipal  securities dealers  who are
approved by the Trust's Board of Trustees.  Each dealer will be approved on  its
own  merits and it is the Trust's  general policy to enter into put transactions
only with those dealers which are determined to present minimal credit risks. In
connection with such  determination, the  Board of Trustees  will review,  among
other  things, the ratings, if available, of  equity and debt securities of such
municipal securities  dealers, their  reputations  in the  municipal  securities
markets,  the net  worth of  such dealers  and their  efficiency in consummating
transactions. Bank  dealers normally  will  be members  of the  Federal  Reserve
System,  and  other  dealers will  be  members  of the  National  Association of
Securities Dealers, Inc. or members of a national securities exchange. The Board
has directed the Investment Manager not to enter into put transactions with, and
to exercise outstanding puts of, any  municipal securities dealer which, in  the
judgment  of the  Investment Manager,  ceases at any  time to  present a minimal
credit risk. In  the event that  a dealer  should default on  its obligation  to
repurchase an underlying security, the Trust is unable to predict whether all or
any  portion of  any loss  sustained could  be subsequently  recovered from such
dealer. The Trust has not to date  and has no intention to purchase put  options
during the coming fiscal year.
 
    In  Revenue Ruling 82-144,  the Internal Revenue  Service stated that, under
certain circumstances, a purchaser of  tax-exempt obligations which are  subject
to  puts will be considered the owner  of the obligations for Federal income tax
purposes. In connection therewith, the Trust has received an opinion of  counsel
to  the effect that  interest on Municipal  Obligations subject to  puts will be
tax-exempt to the Trust.
 
Active Assets California Tax-Free Trust   6
<PAGE>
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    In addition to the investment restrictions enumerated in the Prospectus, the
investment  restrictions  listed  below  have  been  adopted  by  the  Trust  as
fundamental   policies,  except  as  otherwise   indicated.  Under  the  Act,  a
fundamental policy may  not be  changed without  the vote  of the  holders of  a
majority  of the outstanding voting  securities of the Trust,  as defined in the
Investment Company  Act of  1940, as  amended (the  "Act"). Such  a majority  is
defined  in the Act as the lesser of (a)  67% or more of the shares present at a
Meeting of Shareholders of  the Trust, if  the holders of more  than 50% of  the
outstanding  shares of  the Trust  are present  or represented  by proxy  at the
meeting, or  (b) more  than 50%  of the  outstanding shares  of the  Trust.  For
purposes  of the following restrictions and those recited in the Prospectus: (a)
an "issuer" of a security is the entity whose assets and revenues are  committed
to  the payment of interest and  principal on that particular security, provided
that the guarantee of a security will  be considered a separate security; (b)  a
"taxable  security" is any security the interest  on which is subject to federal
income tax;  and  (c)  all  percentage limitations  apply  immediately  after  a
purchase  or initial  investment, and  any subsequent  change in  any applicable
percentage resulting from market fluctuations or  other changes in total or  net
assets does not require elimination of any security from the portfolio.
 
    The  term "bank obligations"  as referred to in  Investment Restriction 3 in
the Prospectus  refers  to  short-term obligations  (including  certificates  of
deposit  and  bankers' acceptances)  of  banks (including  domestic  branches of
foreign banks) subject  to regulation by  the U.S. Government  and having  total
assets  of $1 billion or more, and  instruments secured by such obligations, not
including obligations of foreign branches of domestic banks.
 
    The Trust may not:
 
        1.  Invest in common stock.
 
        2.  Invest  in securities  of any  issuer if,  to the  knowledge of  the
    Trust, any officer or trustee of the Trust or any officer or director of the
    Investment Manager owns more than 1/2 of 1% of the outstanding securities of
    such issuer, and such officers, trustees and directors who own more than 1/2
    of  1% own in  the aggregate more  than 5% of  the outstanding securities of
    such issuer.
 
        3.  Purchase or sell real  estate or interests therein, although it  may
    purchase securities secured by real estate or interests therein.
 
        4.  Purchase or sell commodities or commodity futures contracts.
 
        5.    Purchase  oil, gas  or  other  mineral leases,  rights  or royalty
    contracts, or exploration or development programs.
 
        6.  Write, purchase or sell puts, calls, or combinations thereof  except
    that it may acquire rights to resell Municipal Obligations at an agreed upon
    price and at or within an agreed upon time.
 
        7.    Purchase  securities  of  other  investment  companies,  except in
    connection with a  merger, consolidation, reorganization  or acquisition  of
    assets.
 
        8.   Borrow money, except  that the Trust may borrow  from a bank or the
    Investment Manager  for  temporary  or emergency  purposes  in  amounts  not
    exceeding  5% (taken at the lower of cost  or current value) of the value of
    its total assets (not including the amount borrowed).
 
        9.  Pledge  its assets or  assign or otherwise  encumber them except  to
    secure  borrowings effected within the  limitations set forth in restriction
    (8). To meet the requirements of  regulations in certain states, the  Trust,
    as  a matter of operating policy but not as a fundamental policy, will limit
    any pledge of its assets to 10% of  its net assets so long as shares of  the
    Trust are being sold in those states.
 
Active Assets California Tax-Free Trust   7
<PAGE>
        10.  Issue senior securities as defined in the Act except insofar as the
    Trust may be  deemed to  have issued  a senior  security by  reason of:  (a)
    purchasing any securities on a when-issued or delayed delivery basis; or (b)
    borrowing money in accordance with restrictions described above.
 
        11.  Make loans of money  or securities, except: (a)  by the purchase of
    debt  obligations  in  which  the  Trust  may  invest  consistent  with  its
    investment  objective  and policies;  and  (b) by  investment  in repurchase
    agreements.
 
        12. Make short sales of securities.
 
        13. Purchase securities on margin,  except for such short-term loans  as
    are necessary for the clearance of purchases of portfolio securities.
 
        14.  Engage in  the underwriting  of securities,  except insofar  as the
    Trust may  be deemed  an underwriter  under the  Securities Act  of 1933  in
    disposing of a portfolio security.
 
        15.  Invest for the  purpose of exercising control  or management of any
    other issuer.
 
SPECIAL CONSIDERATIONS RELATING TO CALIFORNIA TAX-EXEMPT SECURITIES
- --------------------------------------------------------------------------------
 
    The Trust  will  be  affected  by  any  political,  economic  or  regulatory
developments  affecting the  ability of  California issuers  to pay  interest or
repay principal on their obligations.  Various developments regarding the  State
of  California ("State") Constitution and State  statutes which limit the taxing
and spending  authority  of  California governmental  entities  may  impair  the
ability of California issuers to maintain debt service on their obligations. The
following  information constitutes only a brief summary and is not intended as a
complete description.
 
    In 1978, Proposition  13, an  amendment to the  California Constitution  was
approved,  limiting real  property valuation for  property tax  purposes and the
power of local governments to increase  real property tax revenues and  revenues
from  other  sources.  Legislation  adopted after  Proposition  13  provided for
assistance  to   local  governments,   including  the   redistribution  of   the
then-existing  surplus in  the General Fund,  reallocation of  revenues to local
governments,  and  assumption   by  the  State   of  certain  local   government
obligations.  However, more  recent legislation  reduced such  state assistance.
There can  be no  assurance that  any particular  level of  State aid  to  local
governments  will  be maintained  in future  years. In  NORDLINGER V.  HAHN, the
United States Supreme Court upheld certain provisions of Proposition 13  against
claims that it violated the equal protection clause of the Constitution.
 
    In  1979,  an  amendment  was  passed  adding  Article  XIIIB  to  the State
Constitution. As  amended  in 1990,  Article  XIIIB imposes  an  "appropriations
limit"  on the spending authority of the State and local government entities. In
general, the  appropriations limit  is based  on certain  1985-86  expenditures,
adjusted  annually  to reflect  changes in  the cost  of living,  population and
certain  services   provided   by   State   and   local   government   entities.
"Appropriations  limit" does  not include  appropriations for  qualified capital
outlay projects, certain increases in transportation-related taxes, and  certain
emergency appropriations.
 
    If  a government entity raises revenues beyond its "appropriations limit" in
any year,  a portion  of the  excess  which cannot  be appropriated  within  the
following  year's limit  must be returned  to the entity's  taxpayers within two
subsequent fiscal  years,  generally  by  a  tax  credit,  refund  or  temporary
suspension  of tax rates or fee schedules. "Debt service" is excluded from these
limitations, and  is defined  as "appropriations  required to  pay the  cost  of
interest and redemption charges, including the funding of any reserve or sinking
fund  required  in connection  therewith,  on indebtedness  existing  or legally
authorized as of January 1, 1979  or on bonded indebtedness thereafter  approved
[by  the voters]." In addition, Article  XIIIB requires the State Legislature to
establish a prudent State reserve, and to require the transfer of 50% of  excess
revenue to the State School Fund; any amounts allocated to the State School Fund
will increase the appropriations limit.
 
Active Assets California Tax-Free Trust   8
<PAGE>
    In  June 1982,  the voters of  California passed two  initiative measures to
repeal the  California gift  and inheritance  tax  laws and  to enact,  in  lieu
thereof,  California death  taxes. California  voters also  passed an initiative
measure to increase, for taxable years  commencing on or after January 1,  1982,
the amount to account for the effects of inflation. Decreases in State and local
revenues in future fiscal years as a consequence of these initiatives may result
in  reductions in allocations of State revenues  to California issuers or in the
ability of California issuers to pay their obligations.
 
    In  1986,  California  voters  approved  an  initiative  statute  known   as
Proposition   62.  This  initiative  (i)  requires  that  any  tax  for  general
governmental purposes imposed by local governments be approved by resolution  or
ordinance  adopted by a two-thirds vote of the governmental entity's legislative
body and by a majority vote of  the electorate of the governmental entity,  (ii)
requires  that any  special tax  (defined as tax  levied for  other than general
governmental purposes) imposed by a local  governmental entity be approved by  a
two-thirds  vote of the voters within that jurisdiction, (iii) restricts the use
of revenues from a special tax to the purposes or for the service for which  the
special  tax was imposed, (iv)  prohibits the imposition of  ad valorem taxes on
real property  by  local  governmental  entities  except  as  permitted  by  the
Proposition  13 amendment, (v) prohibits the imposition of transaction taxes and
sales taxes on  the sale of  real property by  local governments, (vi)  requires
that  any tax  imposed by  a local  government on  or after  August 1,  1985, be
ratified by a majority vote of the  electorate within two years of the  adoption
of the initiative or be terminated by November 15, 1989, (vii) requires that, in
the  event  a local  government  fails to  comply  with the  provisions  of this
measure, a reduction  of the amount  of property tax  revenue allocated to  such
local  government occurs  in an  amount equal to  the revenues  received by such
entity attributable to the tax levied in violation of the initiative, and  (vii)
permits these provisions to be amended exclusively by the voters of the State of
California.
 
   
    In September 1995, the California Supreme Court upheld the constitutionality
of  Proposition 62,  creating uncertainty  as to  the legality  of certain local
taxes enacted by non-charter cities in California without voter approval. It  is
not possible to predict the impact of the decision.
    
 
    In September 1988, the California Court of Appeals in CITY OF WESTMINSTER V.
COUNTY OF ORANGE held that Proposition 62 is unconstitutional to the extent that
it  requires a general tax by  a general city law enacted  on or after August 1,
1985, and  prior to  the effective  date of  Proposition 62,  to be  subject  to
approval   by  a  majority  of  voters.  The  Court  held  that  the  California
Constitution prohibits the imposition of  a requirement that local tax  measures
be  submitted to the  electorate by either  referendum or initiative.  It is not
possible to predict the  impact of this decision  on charter cities, on  special
taxes or on new taxes imposed after the effective date of Proposition 62.
 
    In  1988, State voters approved Proposition 87, which amended Article XVI of
the  State  Constitution  to  authorize   the  State  Legislature  to   prohibit
redevelopment  agencies  from  receiving  any property  tax  revenues  raised by
increased property taxes to repay bonded indebtedness of local government  which
is  not approved by voters on  or before January 1, 1989.  It is not possible to
predict whether the State Legislature will  enact such a prohibition, nor is  it
possible  to predict the impact of  Proposition 87 on redevelopment agencies and
their ability to make payments on outstanding debt obligations.
 
    In November 1988, California voters approved Proposition 98. This initiative
requires that revenues  in excess  of amounts permitted  to be  spent and  which
would  otherwise  be returned  by revision  of  tax rates  or fee  schedules, be
transferred and allocated (up to a maximum of 40%) to the State School Fund  and
be expended solely for purposes of instructional improvement and accountability.
No  such transfer or allocation of funds  will be required if certain designated
state officials determine that annual  student expenditures and class size  meet
certain  criteria as  set forth  in Proposition 98.  Any funds  allocated to the
State School Fund shall cause the appropriation limits to be annually  increased
for any such allocation made in the prior year. Proposition 98 also requires the
State of California to provide a minimum level of funding for public schools and
community colleges. The initiative permits the enactment of legislation, by on a
two-thirds vote, to suspend the minimum funding requirement for one year.
 
Active Assets California Tax-Free Trust   9
<PAGE>
   
    The  State is a party to numerous  legal proceedings, many of which normally
occur in  governmental  operations and,  if  decided against  the  State,  might
require  the  State to  make significant  future  expenditures or  impair future
revenue sources.
    
 
   
    Since 1990,  California has  faced  the worst  economic, fiscal  and  budget
conditions since the 1930's. After experiencing strong growth throughout much of
the  1980's,  the State  was adversely  affected by  the national  recession and
cutbacks in aerospace  and defense  spending, both of  which have  had a  severe
impact  on the economy in Southern  California. California is still experiencing
some effects of the recession. However, economic data indicate that the  State's
economy grew at a modest rate in 1995, and continued growth is expected in 1996.
    
 
   
    On  August 3, 1995, the Governor signed  into law a new $57.5 billion budget
which, among  other things,  reduces welfare  payments and  increases  education
spending  from the  previous fiscal  year. The  fiscal 1995-96  budget calls for
$44.1 billion in  revenues and $43.4  billion in spending,  an increase of  over
3.5%  and  4.0%,  respectively, from  the  fiscal 1994-95  budget.  Although the
State's budget projects an operating  surplus of approximately $600 million,  it
continues  to rely on federal actions, both to fund programs relating to MediCal
and incarceration costs associated  with illegal immigrants  and to relieve  the
State  from federally  mandated spending,  which are  not certain  of occurring.
Accordingly, the  surplus may  not be  realized unless  the economy  outperforms
expectations or spending falls below planned levels.
    
 
    Although  an improving economy  and healthier tax  revenues are anticipated,
the political  environment  and  voter initiatives  may  constrain  the  State's
financial  flexibility.  For  example, according  to  the  Legislative Analyst's
Office the passage of  Proposition 187 in the  November 1994 election, which  in
part  denies certain social services to illegal immigrants, could jeopardize $15
billion in federal funding. In addition,  the passage of Proposition 184 in  the
November  1994 election,  which imposes  mandatory, lengthy  prison sentences on
individuals  convicted  of  three  felonies,  is  expected  to  increase  prison
operating costs by $3 billion annually and increase prison construction costs by
$20 billion.
 
    Because of the State of California's continuing budget problems, the State's
General  Obligation bonds were downgraded in July  1994 from Aa to A by Moody's,
from A+ to A by Standard & Poor's, and from AA to A by Fitch Investors  Service,
Inc.  All three rating agencies expressed  uncertainty in the State's ability to
balance its budget by 1996.
 
   
    On  December  6,  1994,  Orange  County  (California)  became  the   largest
municipality  in  the United  States to  file for  protection under  the Federal
bankruptcy laws. The filing  stemmed from approximately  $1.7 billion in  losses
suffered  by  the  County's investment  pool  due  to investments  in  high risk
"derivative" securities.  In  September  1995  the  state  legislature  approved
legislation permitting Orange County to use for bankruptcy recovery $820 million
over  20 years  in sales  taxes previously  earmarked for  highways, transit and
development. Such legislation also permits the Governor to appoint a trustee  to
take  over Orange County's financial affairs if  the County does not have a full
recovery plan filed with the Bankruptcy Court by May 1996.
    
 
   
    Los Angeles  County,  the  nation's largest  county,  is  also  experiencing
financial difficulty. In August 1995 the credit rating of the county's long-term
bonds  was downgraded for  the third time since  1992 as a  result of, and among
other things, severe operating deficits for the county's health care system.  In
September  1995,  federal and  state aid  to Los  Angeles County  totalling $514
million was  pledged, providing  a short-term  solution to  the County's  budget
problems.  Despite such efforts, the County is  facing a potential budget gap of
$1.0 billion in the 1996-97 fiscal year.
    
 
    The effect  of these  various constitutional  and statutory  amendments  and
budget  developments upon the ability of  California issuers to pay interest and
principal on their obligations remains unclear and in any event may depend  upon
whether  a particular  California tax-exempt  security is  a general  or limited
obligation bond  and on  the  type of  security provided  for  the bond.  It  is
possible  that  other measures  affecting the  taxing  or spending  authority of
California or  its political  subdivisions may  be approved  or enacted  in  the
future.
 
Active Assets California Tax-Free Trust   10
<PAGE>
HOW NET ASSET VALUE IS DETERMINED
- --------------------------------------------------------------------------------
 
    As  discussed in the Appendix to the  Prospectus, the net asset value of the
Trust is determined as of 12  noon New York time on  each day that the New  York
Stock  Exchange  is open.  The New  York Stock  Exchange currently  observes the
following holidays: New Year's Day; President's Day; Good Friday; Memorial  Day;
Independence Day; Labor Day; Thanksgiving Day; and Christmas Day.
 
    The  Trust  utilizes  the amortized  cost  method in  valuing  its portfolio
securities for  purposes of  determining  the net  asset  value of  the  Trust's
shares.  The Trust utilizes  the amortized cost method  in valuing its portfolio
securities even  though the  portfolio securities  may increase  or decrease  in
market  value,  generally, in  connection with  changes  in interest  rates. The
amortized cost  method of  valuation involves  valuing a  security at  its  cost
adjusted  by a  constant amortization  to maturity  of any  discount or premium,
regardless of the impact  of fluctuating interest rates  on the market value  of
the instrument. While this method provides certainty in valuation, it may result
in  periods during which  value, as determined  by amortized cost,  is higher or
lower than the price the Trust would  receive it if sold the instrument.  During
such  periods, the yield to investors in the Trust may differ somewhat from that
obtained in a  similar company  which uses  mark to  market values  for all  its
portfolio  securities. For example, if  the use of amortized  cost resulted in a
lower (higher)  aggregate portfolio  value on  a particular  day, a  prospective
investor  in the Trust would  be able to obtain  a somewhat higher (lower) yield
than would  result  from investment  in  such  a similar  company  and  existing
investors  would  receive less  (more) investment  income.  The purpose  of this
method of calculation is to facilitate  the maintenance of a constant net  asset
value per share of $1.00.
 
    The  Trust's  use  of  the  amortized cost  method  to  value  its portfolio
securities and the  maintenance of the  per share  net asset value  of $1.00  is
permitted  pursuant to Rule 2a-7 of the  Act (the "Rule"), and is conditioned on
its compliance with various conditions contained in the Rule including: (a)  the
Trust's  Trustees  are  obligated,  as a  particular  responsibility  within the
overall duty of care owed to  the Trust's shareholders, to establish  procedures
reasonably  designed,  taking into  account  current market  conditions  and the
Trust's investment objectives,  to stabilize the  net asset value  per share  as
computed  for the purpose of distribution and redemption at $1.00 per share; (b)
(i) the procedures include calculation, at  such intervals as are reasonable  in
light  of current market conditions, of the  deviation, if any between net asset
value per share using amortized cost to value portfolio securities and net asset
value per share  based upon  available market  quotations with  respect to  such
portfolio securities (for the purpose of determining market value, securities as
to  which the Trust has a "put" will be  valued at the higher of market value or
exercise price); (ii) periodic review by the Trustees of the amount of deviation
as well  as methods  used to  calculate  it, and  (iii) maintenance  of  written
records  of the procedures,  the Trustees' considerations  made pursuant to them
and any actions taken upon such  consideration; the Trustees will consider  what
steps  should be taken, if any, in the event of a difference of more than 1/2 of
1% between the two methods of valuation;  and (d) the Trustees should take  such
action as they deem appropriate to eliminate or reduce, to the extent reasonably
practicable,  material dilution or other unfair results to investors or existing
shareholders. Such action  may include: selling  portfolio instruments prior  to
maturity  to realize capital gains or losses or to shorten the average portfolio
maturity of the Trust;  withholding dividends; utilizing a  net asset value  per
share  as determined by using available market quotations or reducing the number
of its outstanding shares. Any reduction of outstanding shares will be  effected
by  having each shareholder proportionately contribute  to the Trust's capital a
number of  shares which  represent  the difference  between the  amortized  cost
valuation and market valuation of the portfolio. Each shareholder will be deemed
to have agreed to such contribution by his or her investment in the Trust.
 
    The  Rule  further requires  that the  Trust limit  its investments  to U.S.
dollar-denominated instruments  which  the Trustees  determine  present  minimal
credit risks and which are Eligible Securities (as defined below). The Rule also
requires the Trust to maintain a dollar-weighted average portfolio maturity (not
more  than 90  days) appropriate  to its objective  of maintaining  a stable net
asset value of $1.00 per share and precludes the purchase of any instrument with
a remaining maturity of more than 397 days. Should
 
Active Assets California Tax-Free Trust   11
<PAGE>
the disposition  of a  portfolio security  result in  a dollar-weighted  average
portfolio  maturity of more  than 90 days,  the Trust will  invest its available
cash in such a manner as to reduce such  maturity to 90 days or less as soon  as
is reasonably practicable.
 
    At  the  time  the  Trust  makes  the  commitment  to  purchase  a Municipal
Obligation on  a when-issued  or  delayed delivery  basis,  it will  record  the
transaction  and  thereafter  reflect  the value,  each  day,  of  the Municipal
Obligation in determining its net asset value. Repurchase agreements are  valued
at  the face value of the repurchase agreement plus any accrued interest thereon
to date.
 
    Generally, for  purposes  of the  procedures  adopted under  the  Rule,  the
maturity  of  a  portfolio  instrument  is to  be  deemed  the  period remaining
(calculated from the trade date or such other date on which the Trust's interest
in the instrument is subject to market action) until the date noted on the  face
of  the instrument as the date on which the principal amount must be paid, or in
the case  of  an  instrument  called  for redemption,  the  date  on  which  the
redemption payment must be made.
 
    A  variable rate obligation that is subject to a demand feature is deemed to
have a maturity  equal to  the longer  of the  period remaining  until the  next
readjustment  of the interest  rate or the period  remaining until the principal
amount can  be recovered  through demand.  A floating  rate instrument  that  is
subject  to a demand  feature is deemed to  have a maturity  equal to the period
remaining until the principal amount can be recovered through demand.
 
   
    An Eligible Security generally is defined in the Rule to mean (i) A security
with a remaining  maturity of  397 calendar  days or  less that  has received  a
short-term  rating (or  that has been  issued by  an issuer that  has received a
short-term rating  with respect  to a  class of  debt obligations,  or any  debt
obligation  within that class, that is  comparable in priority and security with
the security)  by the  Requisite NRSROs  in one  of the  two highest  short-term
rating  categories  (within  which  there may  be  sub-categories  or gradations
indicating relative  standing); or  (ii) A  security: (A)  That at  the time  of
issuance  had a remaining maturity of more than 397 calendar days but that has a
remaining maturity  of 397  calendar days  or  less; and  (B) Whose  issuer  has
received  from the  Requisite NRSROs a  rating with  respect to a  class of debt
obligations (or any debt obligation within that class) that is now comparable in
priority and security with  the security, in one  of the two highest  short-term
rating  categories  (within  which  there may  be  sub-categories  or gradations
indicating  relative  standing);  or  (iii)  An  Unrated  Security  that  is  of
comparable  quality to a security meeting the requirements of (i) or (ii) above,
as determined by the money market fund's board of directors.
    
 
    As permitted by the Rule, the Board has delegated to the Trust's  Investment
Manager,  subject to the Board's oversight pursuant to guidelines and procedures
adopted by  the  Board, the  authority  to determine  which  securities  present
minimal  credit risks and which unrated  securities are comparable in quality to
rated securities.
 
   
    Also, as required by the Rule, with respect to 75% of its total assets,  the
Trust   will  limit  its  investments   in  securities,  other  than  Government
securities, so that, at the time of  purchase: (a) except as further limited  in
(b)  below  with  regard  to certain  securities,  no  more than  5%  (10%  if a
guarantee) of its total  assets will be  invested in the  securities of any  one
issuer;  and (b) with respect to Eligible Securities that have received a rating
in less than the  highest category by  any one of the  NRSROs whose ratings  are
used  to qualify the  security as an  Eligible Security, or  determined to be of
comparable quality that are "conduit securities" as that term is defined in  the
Rule: (i) no more than 5% will be invested in the aggregate of the Trust's total
assets  in all such securities, and (ii) no more than the greater of 1% of total
assets, or $1 million, will be invested in the securities of any one issuer.
    
 
    If the Board determines that  it is no longer in  the best interests of  the
Trust  and its shareholders to maintain a stable price of $1 per share or if the
Board believes that maintaining such price no longer reflects a market-based net
asset value per share, the Board has the right to change from an amortized  cost
basis  of  valuation to  valuation based  on market  quotations. The  Trust will
notify shareholders of any such changes.
 
    The Trust will  manage its  portfolio in an  effort to  maintain a  constant
$1.00  per share price, but  it cannot assure that the  value of its shares will
never deviate from the $1.00 price. Since dividends from
 
Active Assets California Tax-Free Trust   12
<PAGE>
net investment income  are declared  and reinvested on  a daily  basis, the  net
asset  value  per  share,  under ordinary  circumstances,  is  likely  to remain
constant. Realized and unrealized gains and losses will not be distributed on  a
daily  basis but will be reflected in the Trust's net asset value. The amount of
such gains and  losses will  be considered by  the Trustees  in determining  the
action to be taken to maintain the Trust's $1.00 per share net asset value. Such
action  may  include  distribution  at any  time  of  part or  all  of  the then
accumulated  undistributed  net   realized  capital  gains,   or  reduction   or
elimination  of daily dividends  by an amount equal  to part or  all of the then
accumulated net  realized capital  losses. However,  if realized  losses  should
exceed  the sum of net investment income plus realized gains on any day, the net
asset value per share on that day  might decline below $1.00 per share. In  such
circumstances,  the Trust may reduce or eliminate the payment of daily dividends
for a period of  time in an effort  to restore the Trust's  $1.00 per share  net
asset  value.  A decline  in prices  of securities  could result  in significant
unrealized depreciation on a mark to  market basis. In these circumstances,  the
Trust  may reduce or eliminate the payment  of dividends and utilize a net asset
value per share as determined by using available market quotations or reduce the
number of its outstanding shares.
 
DIVIDENDS, DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------
 
    As stated in the  Appendix to the Prospectus,  the Trust intends to  declare
dividends, payable on each day the New York Stock Exchange is open for business,
of  all of its net investment income to shareholders of record as of 12 noon New
York time of the preceding business day.
 
    In computing  interest income,  the  Trust will  amortize any  premiums  and
original  issue discounts on securities owned.  Capital gains or losses realized
upon sale or maturity of such securities will be based on their amortized cost.
 
    Gains or losses on the  sales of securities by  the Trust will be  long-term
capital  gains or losses if the securities have  been held by the Trust for more
than twelve months. Gains or  losses on the sale  of securities held for  twelve
months or less will be short-term capital gains or losses.
 
   
    At   June  30,  1996,  the  Trust  had  a  net  capital  loss  carryover  of
approximately $11,800 of which $10,900 will  be available through June 30,  2002
and  $900 will be available through June 30, 2003 to offset future capital gains
to the extent  provided by regulations.  During the fiscal  year ended June  30,
1996,  the Trust had  utilized capital loss  carryovers of approximately $5,100.
Any net capital losses incurred after October 31 ("Post--October losses") within
the taxable year are deemed  to arise on the first  business day of the  Trust's
next taxable year.
    
 
    The  Trustees may  revise the  dividend policy,  or postpone  the payment of
dividends, if the Trust should have or anticipate any large unexpected  expense,
loss  or fluctuation in net assets which,  in the opinion of the Trustees, might
have a significant  adverse effect  on shareholders.  On occasion,  in order  to
maintain  a constant $1.00  per share net  asset value, the  Trustees may direct
that the number of outstanding shares be reduced in each shareholder's  account.
Such  reduction may result in taxable income, if any, to a shareholder in excess
of the net  increase (i.e.,  dividends, less such  reductions), if  any, in  the
shareholder's  account for a period. Furthermore, such reduction may be realized
as a capital loss when the shares are liquidated.
 
    As discussed in the Prospectus, the Trust intends to invest a portion of its
assets in certain  "private activity bonds"  issued after August  7, 1986. As  a
result,  a portion of the exempt-interest dividends paid by the Trust will be an
item of tax  preference for  taxable years  beginning after  December 31,  1986.
Certain  corporations which are subject to  the alternative minimum tax may also
have to  include  exempt-interest  dividends in  calculating  their  alternative
minimum  taxable income in  situations where the  "adjusted current earnings" of
the corporation exceeds its preadjustment alternative minimum taxable income.
 
    The Trust  has qualified  and intends  to remain  qualified as  a  regulated
investment  company under Subchapter M  of the Code. If  so qualified, the Trust
will not be  subject to  federal income  and excise  tax on  its net  investment
income  and capital gains, if  any, realized during any  fiscal year in which it
distributes such income and capital gains to its shareholders.
 
Active Assets California Tax-Free Trust   13
<PAGE>
    As discussed  in  the  Prospectus,  the Trust  intends  to  qualify  to  pay
"exempt-interest  dividends" to its shareholders by maintaining, as of the close
of each  of  its  taxable years,  at  least  50% of  its  assets  in  tax-exempt
securities.  An exempt-interest dividend is that part of a dividend distribution
made by the Trust which consists of interest received by the Trust on tax-exempt
securities  upon  which  the  shareholder   incurs  no  federal  income   taxes.
Exempt-interest dividends are included, however, in determining what portion, if
any,  of a person's Social  Security benefits are subject  to federal income tax
and in certain circumstances  may affect the  determination of the  supplemental
premium applicable to Medicare eligible individuals.
 
    Alternative minimum taxable income is generally equal to taxable income with
certain  adjustments and increased  by certain "tax  preference items" which may
include a portion of the Trust's dividends as described above. In addition,  the
Code  further provides that for taxable  years beginning in 1990 and thereafter,
corporations are subject to an alternative minimum tax based, in part, on 75% of
any excess of "adjusted  current earnings" over taxable  income as adjusted  for
other  tax preferences.  Because an exempt-interest  dividend paid  by the Trust
will be  included in  adjusted  current earnings,  a corporate  shareholder  may
therefore  be required to pay an increased alternative minimum tax as the result
of receiving exempt-interest dividends paid by the Trust.
 
    The Superfund Amendments  and Reauthorization  Act of  1986 (the  "Superfund
Act")  imposes a deductible  tax on a  corporation's alternative minimum taxable
income (computed  without  regard to  the  alternative tax  net  operating  loss
deduction)  at a rate of $12 per  $10,000 (0.12%) of alternative minimum taxable
income in  excess of  $2,000,000. The  tax  will be  imposed for  taxable  years
beginning  after December 31, 1986  and before January 1,  1996. The tax will be
imposed even if the  corporation is not required  to pay an alternative  minimum
tax  because the corporation's regular income  tax liability exceeds its minimum
tax  liability.  Exempt-interest  dividends  paid  by  the  Trust  that   create
alternative  minimum tax preferences  for corporate shareholders  under the Code
(as described above) may be subject to the tax.
 
    Within 60 days  after the end  of its fiscal  year, the Trust  will mail  to
shareholders a statement indicating the percentage of the dividend distributions
for  such  fiscal  year  which  constitutes  exempt-interest  dividends  and the
percentage, if any, that is taxable, and  to what extent the taxable portion  is
long-term  capital  gain,  short-term  capital  gain  or  ordinary  income. This
percentage should be applied uniformly to all monthly distributions made  during
the fiscal year to determine the proportion of dividends that is tax-exempt. The
percentage  may differ from the  percentage of tax-exempt dividend distributions
for any particular month.
 
    Shareholders will be subject  to federal income tax  on dividends paid  from
interest income derived from taxable securities and on distributions of realized
net  short-term capital gains. Such interest and realized net short-term capital
gains dividends and  distributions are  taxable to the  shareholder as  ordinary
dividend   income   regardless  of   whether   the  shareholder   receives  such
distributions in  additional  shares  or in  cash.  Distributions  of  long-term
capital gains, if any, are taxable as long-term capital gains, regardless of how
long  the shareholder  has held  the Fund shares  and regardless  of whether the
distribution is received in additional shares or cash. Since the Trust's  income
is  expected to be derived  entirely from interest rather  than dividends, it is
anticipated that none of  such dividend distributions will  be eligible for  the
federal dividends received deduction available to corporations.
 
    Any loss on the sale or exchange of shares of the Trust which are held for 6
months  or less is disallowed to the extent of the amount of any exempt-interest
dividend paid with respect to such shares. Treasury Regulations may provide  for
a reduction in such required holding periods.
 
    The  Code requires each regulated investment  company to pay a nondeductible
4% excise  tax  to the  extent  the company  does  not distribute,  during  each
calendar  year, 98% of its ordinary income, determined on a calendar year basis,
and 98% of its capital gains, determined  in general on an October 31 year  end,
plus   certain  undistributed   amounts  from   previous  years.   The  required
distributions, however, are  based only  on the  taxable income  of a  regulated
investment  company such as the Trust, which pays exempt-interest dividends. The
Trust anticipates that  it will  make sufficient timely  distributions to  avoid
imposition of the excise tax.
 
Active Assets California Tax-Free Trust   14
<PAGE>
    Interest  on indebtedness incurred or continued by a shareholder to purchase
or carry shares of the Trust is not deductible. Furthermore, entities or persons
who are  "substantial users"  (or  related persons)  of facilities  financed  by
industrial development bonds should consult their tax advisers before purchasing
shares  of  the Trust.  "Substantial user"  is defined  generally by  Income Tax
Regulation 1.103-11 (b) as including a "non-exempt person" who regularly uses in
a trade  or  business  a part  of  a  facility financed  from  the  proceeds  of
industrial development bonds.
 
    From  time to time,  proposals have been introduced  before Congress for the
purpose of  restricting or  eliminating  the federal  income tax  exemption  for
interest  on municipal  securities. Similar proposals  may be  introduced in the
future. If such a  proposal were to be  enacted, the availability of  tax-exempt
municipal  securities for  investment by  the Trust  could be  affected. If such
legislation is enacted, the  Trust may reevaluate  its investment objective  and
policies.
 
    The  exemption of interest  income for federal income  tax purposes does not
necessarily result in exemption under the income or other tax laws of any  state
or  local taxing authority.  Thus, shareholders of  the Trust may  be subject to
state and local taxes on exempt-interest dividends. Shareholders should  consult
their  tax advisers about  the status of  dividends from the  Trust in their own
states and  localities.  The Trust  will  report annually  to  shareholders  the
percentage of interest income received by the Trust during the preceding year on
tax-exempt  obligations, indicating,  on a  state-by-state basis,  the source of
such income.
 
    Under  present  Massachusetts  law,  the   Trust  is  not  subject  to   any
Massachusetts  income tax during any fiscal year in which the Trust qualifies as
a regulated  investment company.  The Trust  might be  subject to  Massachusetts
income taxes for any taxable year in which it does not so qualify as a regulated
investment company.
 
    To  the  extent  that  dividends are  derived  from  interest  on California
tax-exempt securities and on certain U.S. government securities, such  dividends
will also be exempt from California personal income taxes. Under California law,
a  fund which qualifies as a regulated investment company must have at least 50%
of its total assets invested in California  state and local issues, and in  U.S.
obligations  which, if held by an individual, would pay interest excludable from
income or in a combination of such obligations at the end of each quarter of its
taxable year in order  to be eligible to  pay dividends to California  residents
which  will be exempt from California personal income taxes. Unlike federal law,
California law provides that  no portion of  the exempt-interest dividends  will
constitute  an item of tax preference for California personal income alternative
minimum tax purposes. In addition,  unlike federal law, the California  personal
income  tax does  not apply  to any portion  of an  individual's Social Security
benefits.
 
    For California personal income tax purposes, distributions paid from capital
gains are  taxable as  ordinary income.  In addition,  unlike federal  law,  the
shareholders  of the Trust will  not be subject to tax,  or receive a credit for
taxes paid  by the  Trust, on  undistributed capital  gains, if  any. Under  the
California  Revenue  and Taxation  Code,  interest on  indebtedness  incurred or
continued  to  purchase  or  carry  shares  of  an  investment  company   paying
exempt-interest  dividends, such  as the  Trust, will  not be  deductible by the
investor for state personal income tax purposes.
 
    The foregoing relates to federal income taxation and to California  personal
income  taxation as in  effect as of  the date of  the Prospectus. Distributions
from interest income and capital gains, including exempt-interest dividends, may
be subject to  California franchise  taxes if  received by  a corporation  doing
business  in California, to state  taxes in states other  than California and to
local taxes.
 
    Any dividends or capital gains distributions received by a shareholder  from
any  investment company will have the effect  of reducing the net asset value of
the shareholder's stock in  that fund by  the exact amount  of the dividends  or
capital  gains distribution.  Furthermore, capital gains  distributions are, and
some portion of the dividends  may be, subject to income  tax. If the net  asset
value  of the shares should be reduced below a shareholder's cost as a result of
the distribution  of realized  net long-term  capital gains,  such  distribution
would  be a return  of capital but  nonetheless taxable at  capital gains rates.
Therefore, an investor should not purchase  Trust shares immediately prior to  a
distribution  record date  and sell them  immediately thereafter  solely for the
purpose of receiving the distribution.
 
INFORMATION ON COMPUTATION OF YIELD
 
    The Trust's annualized current yield, as may be quoted from time to time  in
advertisements and other communications to shareholders and potential investors,
is  computed  by determining,  for a  stated seven-day  period, the  net change,
exclusive  of   capital  changes   and  including   the  value   of   additional
 
Active Assets California Tax-Free Trust   15
<PAGE>
shares  purchased  with dividends  and any  dividends declared  therefrom (which
reflect deductions of all expenses of the Trust such as management fees), in the
value of a hypothetical  pre-existing account having a  balance of one share  at
the  beginning of the  period, and dividing  the difference by  the value of the
account at the beginning of  the base period to  obtain the base period  return,
and then multiplying the base period return by (365/7).
 
    The  Trust's annualized effective yield, as may  be quoted from time to time
in  advertisements  and  other  communications  to  shareholders  and  potential
investors,  is computed by determining (for  the same stated seven-day period as
for the  current  yield), the  net  change,  exclusive of  capital  changes  and
including  the  value  of additional  shares  purchased with  dividends  and any
dividends declared therefrom (which  reflect deductions of  all expenses of  the
Trust  such as  management fees),  in the  value of  a hypothetical pre-existing
account having  a balance  of one  share at  the beginning  of the  period,  and
dividing the difference by the value of the account at the beginning of the base
period  to obtain the base  period return, and then  compounding the base period
return by adding 1, raising the  sum to a power equal  to 365 divided by 7,  and
subtracting 1 from the result.
 
    The  yields quoted in any advertisement or other communication should not be
considered a representation of the yields of  the Trust in the future since  the
yield  is not fixed. Actual yields will depend not only on the type, quality and
maturities of the investments held by the Trust and changes in interest rates on
such investments, but also on changes in the Trust's expenses during the period.
 
    Yield information may be  useful in reviewing the  performance of the  Trust
and  for providing  a basis for  comparison with  other investment alternatives.
However, unlike bank deposits or other  investments which typically pay a  fixed
yield for a stated period of time, the Trust's yield fluctuates.
 
    Tax-equivalent  yield is  computed by dividing  that portion  of the current
yield (calculated as described  above) which is tax-exempt  by 1 minus a  stated
tax  rate and adding the quotient  to that portion, if any,  of the yield of the
Trust that is not tax-exempt.
 
   
    The Trust's current yield for the seven days ended June 30, 1996 was  2.71%.
The effective annual yield on 2.71% is 2.74%, assuming daily compounding.
    
 
   
    Based  upon a combined Federal and California personal income tax bracket of
46.24%, the Trust's tax-equivalent yield for the seven days ended June 30,  1996
was  5.04%. Tax-equivalent  yield is  computed by  dividing that  portion of the
current yield (calculated as described above)  which is tax-exempt by 1 minus  a
stated tax rate and adding the quotient to that portion, if any, of the yield of
the Trust that is not tax-exempt.
    
 
Active Assets California Tax-Free Trust   16
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
<TABLE>
<S>                                            <C>
ASSETS:
Investments in securities, at value
  (amortized cost $430,773,691)..............  $ 430,773,691
Cash.........................................      1,222,292
Interest receivable..........................      2,297,311
Deferred organizational expenses.............          3,486
Prepaid expenses and other assets............         11,964
                                               -------------
        TOTAL ASSETS.........................    434,308,744
                                               -------------
LIABILITIES:
Payable for:
  Investments purchased......................     49,813,510
  Investment management fee..................        147,543
  Plan of distribution fee...................         29,509
  Shares of beneficial interest
    repurchased..............................             30
Accrued expenses.............................         99,988
                                               -------------
        TOTAL LIABILITIES....................     50,090,580
                                               -------------
NET ASSETS:
Paid-in-capital..............................    384,229,943
Accumulated undistributed net investment
  income.....................................             85
Accumulated net realized loss................        (11,864)
                                               -------------
        NET ASSETS...........................  $ 384,218,164
                                               -------------
                                               -------------
NET ASSET VALUE PER SHARE, 384,229,943 shares
 outstanding (unlimited shares authorized of
 $.01 par value).............................
                                                       $1.00
                                               -------------
                                               -------------
</TABLE>
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                             <C>
NET INVESTMENT INCOME:
INTEREST INCOME...............................  $12,316,979
                                                -----------
EXPENSES
  Investment management fee...................    1,781,282
  Plan of distribution fee....................      351,571
  Transfer agent fees and expenses............       73,519
  Professional fees...........................       52,993
  Shareholder reports and notices.............       36,587
  Registration fees...........................       33,292
  Trustees' fees and expenses.................       30,508
  Custodian fees..............................       21,790
  Organizational expenses.....................        9,264
  Other.......................................        7,126
                                                -----------
      TOTAL EXPENSES BEFORE EXPENSE OFFSET....    2,397,932
      LESS: EXPENSE OFFSET....................      (21,574)
                                                -----------
      TOTAL EXPENSES AFTER EXPENSE OFFSET.....    2,376,358
                                                -----------
      NET INVESTMENT INCOME...................    9,940,621
  NET REALIZED GAIN...........................        5,093
                                                -----------
      NET INCREASE............................  $ 9,945,714
                                                -----------
                                                -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                 FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                                    JUNE 30,1996       JUNE 30, 1995
                                                                                 ------------------  ------------------
<S>                                                                              <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income......................................................    $    9,940,621      $    8,592,974
    Net realized gain..........................................................             5,093            --
                                                                                 ------------------  ------------------
        Net increase...........................................................         9,945,714           8,592,974
 
    Dividends from net investment income.......................................        (9,940,586)         (8,593,044)
    Net increase from transactions in shares of beneficial interest............        70,646,849          25,060,313
                                                                                 ------------------  ------------------
        Total increase.........................................................        70,651,977          25,060,243
NET ASSETS:
  Beginning of period..........................................................       313,566,187         288,505,944
                                                                                 ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $85 and $50,
   respectively)...............................................................    $  384,218,164      $  313,566,187
                                                                                 ------------------  ------------------
                                                                                 ------------------  ------------------
</TABLE>
    
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       17
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.    ORGANIZATION AND  ACCOUNTING  POLICIES--Active Assets  California Tax-Free
Trust (the "Trust") is registered under  the Investment Company Act of 1940,  as
amended  (the "Act"), as a  diversified, open-end management investment company.
The Trust's investment  objective is  to provide a  high level  of daily  income
which is exempt from federal and California income tax consistent with stability
of  principal and liquidity. The Trust was organized as a Massachusetts business
trust on July 10, 1991 and commenced operations on November 12, 1991.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions that affect  the reported  amounts and  disclosures. Actual  results
could  differ from  those estimates. The  following is a  summary of significant
accounting policies:
 
    A.  VALUATION OF INVESTMENTS--Portfolio  securities are valued at  amortized
    cost, which approximates market value.
 
    B.   ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for on
    the trade date (date the order to  buy or sell is executed). Realized  gains
    and  losses on security  transactions are determined  by the identified cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.  FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with  the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies  and to distribute all of its taxable and nontaxable income to its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
    E.  ORGANIZATIONAL EXPENSES--Dean Witter InterCapital Inc. (the  "Investment
    Manager")  paid the  organizational expenses of  the Trust in  the amount of
    approximately $46,500  which  have  been  reimbursed  for  the  full  amount
    thereof.  Such expenses  have been deferred  and are being  amortized by the
    Trust on a straight-line basis over a  period not to exceed five years  from
    the commencement of operations.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement, the Trust pays the Investment Manager a management fee, accrued daily
and payable monthly, by applying the following annual rates to the net assets of
the Trust determined as of the close of each business day: 0.50% to the  portion
of the daily net assets not exceeding $500 million; 0.425% to the portion of the
daily  net assets exceeding $500 million  but not exceeding $750 million; 0.375%
to the portion of the daily net assets exceeding $750 million but not  exceeding
$1  billion; 0.35% to the  portion of the daily  net assets exceeding $1 billion
but not exceeding $1.5 billion;  0.325% to the portion  of the daily net  assets
exceeding $1.5 billion but not exceeding $2 billion; 0.30% to the portion of the
daily  net assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% to
the portion of the daily net assets exceeding $2.5 billion but not exceeding  $3
billion; and 0.25% to the portion of the daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
                                       18
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the  Trustees  determine  to  reimburse,  as  described  below.  The   following
activities   and  services  may  be  provided   by  the  Distributor  and  other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average  daily net assets during the month. Expenses incurred by the Distributor
pursuant to the  Plan in any  fiscal year will  not be reimbursed  by the  Trust
through  payments accrued in any subsequent fiscal year. For the year ended June
30, 1996, the distribution fee was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases  and proceeds  from sales/maturities  of portfolio  securities for the
year ended June 30, 1996 aggregated $903,720,425 and $795,338,000, respectively.
 
   
    Dean Witter  Trust  Company, an  affiliate  of the  Investment  Manager  and
Distributor,  is the  Trust's transfer  agent. At June  30, 1996,  the Trust had
transfer agent fees and expenses payable of approximately $5,800.
    
 
   
    The Trust  has  an unfunded  noncontributory  defined benefit  pension  plan
covering  all  independent Trustees  of the  Trust  who will  have served  as an
independent Trustee for at least five years at the time of retirement.  Benefits
under  this plan are based on years  of service and compensation during the last
five years of service. Aggregate pension cost  for the year ended June 30,  1996
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $14,185. At  June 30, 1996,  the Trust  had an accrued  pension liability  of
$30,297  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
    
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     1,301,311,516      1,156,418,032
Shares issued in reinvestment of dividends.......................................         9,940,586          8,593,044
                                                                                   -----------------  -----------------
                                                                                      1,311,252,102      1,165,011,076
Shares repurchased...............................................................    (1,240,605,253)    (1,139,950,763)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        70,646,849         25,060,313
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
 
                                       19
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
   
6.   FEDERAL INCOME TAX  STATUS--At June 30, 1996, the  Trust had a capital loss
carryover of approximately $11,800  of which $10,900  will be available  through
June  30, 2002 and $900 will be available through June 30, 2003 to offset future
capital gains to the extent provided by regulations. During the year ended  June
30,  1996,  the  Trust had  utilized  capital loss  carryovers  of approximately
$5,100.
    
 
7.  SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table  on
page 3 of this Prospectus.
 
                                       20
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
  PRINCIPAL
  AMOUNT (IN                                                                                COUPON      DEMAND
  THOUSANDS)                                                                                RATE+        DATE*        VALUE
- --------------                                                                           ------------  ---------  -------------
<C>             <S>                                                                      <C>           <C>        <C>
                CALIFORNIA TAX-EXEMPT SHORT-TERM VARIABLE RATE
                MUNICIPAL OBLIGATIONS (63.1%)
  $    4,000    Big Bear Lake, Southwest Gas Corp 1993 Ser A (AMT).....................        3.30%   07/08/96   $   4,000,000
      11,970    California Alternative Energy Finance Authority, General Electric
                  Capital Corp-Arroyo Energy Ser 1993 B (AMT)..........................        3.10    07/08/96      11,970,000
                California Health Facilities Financing Authority,
       2,700      Catholic HealthCare West 1988 Ser A..................................        3.00    07/08/96       2,700,000
       3,800      Childrens Hospital of Orange County Ser 1991 (MBIA)..................        3.00    07/08/96       3,800,000
       5,360      Huntington Memorial Hospital Ser 1985................................        3.15    07/08/96       5,360,000
       6,900      Kaiser Permanente Ser 1993 A.........................................        3.00    07/08/96       6,900,000
      19,000      Memorial Health Services Ser 1994....................................        3.00    07/08/96      19,000,000
      10,000      St Francis Medical Center 1995 Ser E (MBIA)..........................        3.00    07/08/96      10,000,000
       4,570      St. Joseph Health System Ser 1985 B..................................        3.00    07/01/96       4,570,000
                California Housing Finance Agency,
       3,000      1995 Ser E (AMT).....................................................        3.50    08/01/96       3,000,000
       5,000      Home Mtg 1996 Ser J (AMT) (WI).......................................        4.00    07/24/97       5,000,000
                California Pollution Control Financing Authority,
       2,720      Chevron USA Ser 1983.................................................        4.00    11/15/96       2,727,096
       7,300      Chevron USA Ser 1984 B...............................................        3.70    06/16/97       7,306,129
       1,750      Noranda-Grey Eagle Mines Inc 1984 Ser B..............................        3.40    07/08/96       1,750,000
       5,000      North County Recycling Center 1991 Ser B.............................        2.80    07/08/96       5,000,000
      10,000      Pacific Gas & Electric Co Ser 1996 B (AMT)...........................        3.40    07/08/96      10,000,000
       6,700      Pacific Gas & Electric Co Ser 1996 F.................................        3.40    07/01/96       6,700,000
       7,800      Stanislaus Inc Ser 1987 (AMT)........................................        3.70    07/01/96       7,800,000
      14,000    California Public Capital Improvements Financing Authority, Pooled Ser
                  1988 C...............................................................        3.65    09/15/96      14,000,000
                California Statewide Communities Development Authority,
       5,000      House Ear Institute 1993 Ser A COPs..................................        3.35    07/01/96       5,000,000
       9,000      Kaiser Permanente Ser 1995 COPs......................................        3.00    07/08/96       9,000,000
       5,000      St Joseph Health System Grp COPs.....................................        3.00    07/01/96       5,000,000
      10,000    Foothill/Eastern Transportation Corridor Agency, Toll Road Ser 1995 C..        3.10    07/08/96      10,000,000
      10,000    Long Beach, Memorial Health Services Ser 1991..........................        3.00    07/08/96      10,000,000
       2,900    Los Angeles, Multi-Family 1985 Ser K...................................        3.10    07/08/96       2,900,000
       8,000    Los Angeles County Metropolitan Transportation Authority, Prop C Sales
                  Tax Refg Ser 1993 A (MBIA)...........................................        3.00    07/08/96       8,000,000
       5,000    Northern California Public Power Agency, Geothermal No 3 1996 Ser A
                  (AMBAC)..............................................................        3.15    07/08/96       5,000,000
       4,600    Ontario Redevelopment Agency, Daisy XX Assoc Ltd Ser 1984..............        2.90    07/08/96       4,600,000
       3,900    Redlands, Orange Village Apts 1988 Ser A (AMT).........................        3.15    07/08/96       3,900,000
      10,400    Sacramento County, Administration Center & Courthouse Ser 1990 COPs....        3.10    07/08/96      10,400,000
       6,600    San Jose-Santa Clara Clean Water Financing Authority, Sewer Ser 1995 B
                  (FGIC)...............................................................        3.15    07/08/96       6,600,000
       7,000    Santa Clara County-El Camino Hospital District Hospital Facilities
                  Authority, Valley Medical Center 1985 Ser A..........................        3.10    07/08/96       7,000,000
      14,800    Southern California Public Power Authority, Transmission 1991 Refg Ser
                  (AMBAC)..............................................................        3.10    07/08/96      14,800,000
       4,315    Tri City Housing Finance Agency, Single Family Ser 1994 (AMT)..........        4.00    07/01/96       4,315,000
       4,310    Turlock, Irrigation District Ser 1988 A................................        3.10    07/08/96       4,310,000
                                                                                                                  -------------
                TOTAL CALIFORNIA TAX-EXEMPT SHORT-TERM VARIABLE RATE
                  MUNICIPAL OBLIGATIONS (AMORTIZED COST $242,408,225)...........................................    242,408,225
                                                                                                                  -------------
</TABLE>
    
 
                                       21
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                                       YIELD TO
  PRINCIPAL                                                                                            MATURITY
  AMOUNT (IN                                                                   COUPON     MATURITY    ON DATE OF
  THOUSANDS)                                                                    RATE        DATE       PURCHASE         VALUE
- --------------                                                              ------------  ---------  -------------  -------------
<C>             <S>                                                         <C>           <C>        <C>            <C>
                CALIFORNIA TAX-EXEMPT COMMERCIAL PAPER (32.7%)
  $    6,000    California, Ser 1996......................................        3.55%   08/22/96        3.55 %    $   6,000,000
                California Department of Water Resources,
       4,400      Ser I...................................................        3.30    10/10/96        3.30          4,400,000
       4,500      Ser I...................................................        3.30    10/30/96        3.30          4,500,000
                California Pollution Control Financing Authority,
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    07/25/96        3.30          4,000,000
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    08/08/96        3.30          4,000,000
       4,000      Pacific Gas & Electric Co 1988 Ser C....................        3.30    08/15/96        3.30          4,000,000
       2,100      Southern California Edison Co Ser 1985 B................        3.05    08/13/96        3.05          2,100,000
       3,000      Southern California Edison Co Ser 1985 A................        3.50    08/13/96        3.50          3,000,000
       3,500      Southern California Edison Co Ser 1985 A................        3.30    10/08/96        3.30          3,500,000
       2,900      Southern California Edison Co Ser 1985 A................        3.40    10/08/96        3.40          2,900,000
       5,000      Thermal Energy Dev Ptnrsp Ser A (AMT)...................        3.65    08/23/96        3.65          5,000,000
       5,000    Chula Vista, San Diego Gas & Electric Co Ser 1992 C
                  (AMT)...................................................        3.55    08/29/96        3.55          5,000,000
       5,000    Delmar Race Track Authority, 1993 BANs....................        3.35    08/15/96        3.35          5,000,000
                East Bay Municipal Utility District,
       5,500      Water...................................................        3.40    08/27/96        3.40          5,500,000
       3,500      Water...................................................        3.50    08/27/96        3.50          3,500,000
       4,000    Long Beach Harbor Department, Ser A (AMT).................        3.35    07/12/96        3.35          4,000,000
                Los Angeles Department of Water & Power,
       4,000      Electric................................................        3.55    07/31/96        3.55          4,000,000
       5,600      Electric................................................        3.45    08/21/96        3.45          5,600,000
       4,500    Metropolitan Water District of Southern California, Ser
                  1991....................................................        3.45    08/26/96        3.45          4,500,000
       6,000      Ser 1995 B..............................................        3.40    09/19/96        3.40          6,000,000
       5,000      Ser 1995 B..............................................        3.40    09/24/96        3.40          5,000,000
                Sacramento Municipal Utility District,
       3,000      Ser I...................................................        3.35    07/30/96        3.35          3,000,000
       4,000      Ser I...................................................        3.30    09/25/96        3.30          4,000,000
                San Diego,
       7,500      San Diego Gas & Electric Co Ser 1995 B..................        3.50    08/06/96        3.50          7,500,000
       4,050      San Diego Gas & Electric Co Ser 1995 A..................        3.50    10/24/96        3.50          4,050,000
                West & Central Basin Financing Authority,
       3,000      West Basin Municipal Water District TRANs...............        3.05    08/07/96        3.05          3,000,000
       4,000      West Basin Municipal Water District TRANs...............        3.50    08/19/96        3.50          4,000,000
                PUERTO RICO
       4,000    Puerto Rico Government Development Bank,..................        3.65    09/11/96        3.65          4,000,000
       4,500    Puerto Rico Government Development Bank,..................        3.60    09/18/96        3.60          4,500,000
                                                                                                                    -------------
                TOTAL CALIFORNIA TAX-EXEMPT COMMERCIAL PAPER
                  (AMORTIZED COST $125,550,000)...................................................................    125,550,000
                                                                                                                    -------------
</TABLE>
    
 
                                       22
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
   
<TABLE>
<CAPTION>
                                                                                                       YIELD TO
  PRINCIPAL                                                                                            MATURITY
  AMOUNT (IN                                                                   COUPON     MATURITY    ON DATE OF
  THOUSANDS)                                                                    RATE        DATE       PURCHASE         VALUE
- --------------                                                              ------------  ---------  -------------  -------------
                CALIFORNIA TAX-EXEMPT SHORT-TERM MUNICIPAL NOTES (16.3%)
<C>             <S>                                                         <C>           <C>        <C>            <C>
  $    9,000    California School Cash Reserve Program Authority, 1995
                  Pool Ser A, dtd 07/05/95................................        4.75%   07/03/96        3.75 %    $   9,000,947
      13,000    Contra Costa County, 1996-1997 TRANs, dtd 07/01/96 (WI)...        4.50    07/03/97        3.76         13,094,110
       7,000    Riverside County, 1996-1997 Ser A TRANs, dtd 07/01/96
                  (WI)....................................................        4.50    06/30/97        3.90          7,040,250
       7,000    San Bernadino County, 1996-1997 TRANs, dtd 07/01/96
                  (WI)....................................................        4.50    06/30/97        3.875         7,042,000
      10,000    San Diego, 1996-1997 Ser A TANs, dtd 07/02/96 (WI)........        4.50    07/02/97        3.75         10,072,200
       9,000    Santa Barbara County, 1995-1996 Ser A TRANs, dtd
                  07/06/95................................................        4.50    07/05/96        3.79          9,001,009
       7,500    Ventura County, Ser 1996 TRANs, dtd 07/02/96 (WI).........        4.75    07/02/97        3.85          7,564,950
                                                                                                                    -------------
                TOTAL CALIFORNIA TAX-EXEMPT SHORT-TERM MUNICIPAL NOTES
                  (AMORTIZED COST $62,815,466)....................................................................     62,815,466
                                                                                                                    -------------
              TOTAL INVESTMENTS (AMORTIZED COST $430,773,691) (A)........................      112.1%     430,773,691
              LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS.............................      (12.1)     (46,555,527)
                                                                                           -----------   ------------
              NET ASSETS.................................................................      100.0%    $384,218,164
                                                                                           -----------   ------------
                                                                                           -----------   ------------
</TABLE>
    
 
- ------------
 
      AMT        ALTERNATIVE MINIMUM TAX.
     BANS        BOND ANTICIPATION NOTES.
     COPS        CERTIFICATES OF PARTICIPATION.
     TANS        TAX ANTICIPATION NOTES.
     TRANS       TAX AND REVENUE ANTICIPATION NOTES.
      WI         SECURITY PURCHASED ON A WHEN ISSUED BASIS.
       +         RATE SHOWN IS RATE IN EFFECT AT JUNE 30, 1996.
                 DATE IN WHICH THE PRINCIPAL AMOUNT CAN BE
       *         RECOVERED THROUGH DEMAND.
      (A)        COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
BOND INSURANCE:
     AMBAC       AMBAC INDEMNITY CORPORATION.
     FGIC        FINANCIAL GUARANTY INSURANCE COMPANY.
     MBIA        MUNICIPAL BOND INVESTORS ASSURANCE CORPORATION.
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       23
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets California Tax-Free Trust
 
   
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material  respects,  the  financial position  of  Active  Assets California
Tax-Free Trust (the "Trust") at June 30, 1996, the results of its operations for
the year then ended, the changes in its net assets for each of the two years  in
the period then ended and the financial highlights for each of the four years in
the  period then  ended and  for the period  November 12,  1991 (commencement of
operations) through  June  30,  1992,  in  conformity  with  generally  accepted
accounting  principles.  These  financial  statements  and  financial highlights
(hereafter referred to as "financial statements") are the responsibility of  the
Trust's  management;  our  responsibility  is to  express  an  opinion  on these
financial statements  based on  our audits.  We conducted  our audits  of  these
financial  statements in  accordance with generally  accepted auditing standards
which require that we plan and perform the audit to obtain reasonable  assurance
about  whether the  financial statements are  free of  material misstatement. An
audit includes examining, on a test  basis, evidence supporting the amounts  and
disclosures  in the  financial statements,  assessing the  accounting principles
used and significant estimates  made by management,  and evaluating the  overall
financial  statement presentation.  We believe  that our  audits, which included
confirmation of securities at June 30, 1996 by correspondence with the custodian
and brokers, provide a reasonable basis for the opinion expressed above.
    
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                      1996 FEDERAL TAX NOTICE (UNAUDITED)
During the year ended June 30, 1996,  the Trust paid to shareholders $0.028  per
share  from  net  investment  income.  All of  the  Trust's  dividends  from net
investment income were exempt interest  dividends, excludable from gross  income
for Federal income tax purposes.
 
                                       24
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
<PAGE>
   
STATEMENTS OF ADDITIONAL INFORMATION
AUGUST 22, 1996                                                           [LOGO]
    
 
- --------------------------------------------------------------------------------
 
    Active  Assets Money Trust (the "Money Trust"  or the "Trust") is a no-load,
diversified open-end management investment  company whose investment  objectives
are  high current income, preservation of capital and liquidity. The Money Trust
seeks to  achieve its  objectives by  investing in  a diversified  portfolio  of
short-term money market instruments.
 
    Active  Assets Tax-Free  Trust (the  "Tax-Free Trust"  or the  "Trust") is a
no-load, diversified  open-end management  investment company  whose  investment
objective  is to  provide as high  a level  of daily income  exempt from federal
personal income tax as is consistent with stability of principal and  liquidity.
The Tax-Free Trust seeks to achieve its objective by investing primarily in high
quality tax-exempt securities with short-term maturities.
 
    Active  Assets California Tax-Free Trust (the "California Tax-Free Trust" or
the "Trust") is  a no-load, diversified  open-end management investment  company
whose  investment objective is to provide as high a level of daily income exempt
from federal and California personal income tax as is consistent with  stability
of  principal and liquidity. The California  Tax-Free Trust seeks to achieve its
objective by  investing primarily  in high  quality tax-exempt  securities  with
short-term maturities.
 
    Active Assets Government Securities Trust (the "Government Securities Trust"
or the "Trust") is a no-load, diversified open-end management investment company
whose investment objectives are high current income, preservation of capital and
liquidity.  The Government  Securities Trust seeks  to achieve  its objective by
investing in U.S. Government securities, including a variety of securities which
are issued  or guaranteed  by  the United  States  Government, its  agencies  or
instrumentalities.
 
   
    Prospectuses  for  the  Money  Trust,  the  Tax-Free  Trust,  the California
Tax-Free Trust and the Government Securities  Trust, all dated August 22,  1996,
which  provide the basic information you should  know before investing in any of
the aforementioned Trusts, may be obtained without charge from any of the Trusts
at the address or telephone number listed below. These Statements of  Additional
Information  are not Prospectuses.  They contain information  in addition to and
more detailed than  that set  forth in the  Prospectuses. They  are intended  to
provide  additional information regarding  the activities and  operations of the
Trusts, and should be read in conjunction with the Prospectuses. They should  be
read  with the information appearing  in the Appendix hereto  which is a part of
these Statements of Additional Information.
    
 
Active Assets Money Trust
Active Assets Tax-Free Trust
Active Assets California Tax-Free Trust
Active Assets Government Securities Trust
 
Two World Trade Center
New York, New York 10048
(212) 392-2550
 
    The shares of the Money Trust,  the Tax-Free Trust, the California  Tax-Free
Trust  and the  Government Securities Trust  are offered to  participants in the
Active Assets Account program of Dean  Witter Reynolds Inc. ("Dean Witter").  In
addition,  shares of the  Trusts are offered  to investors maintaining brokerage
accounts with Dean Witter who are not subscribers to the Active Assets  program.
For  further information,  either consult  the Dean  Witter Client  Agreement or
consult your Dean Witter Account Executive.
 
Active Assets Government Securities Trust
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
TABLE OF CONTENTS
- --------------------------------------------------------------------------------
 
   
<TABLE>
<S>                                                                    <C>
Investment Practices and Policies.....................................     3
 
Investment Restrictions...............................................     5
 
How Net Asset Value is Determined.....................................     6
 
Dividends, Distributions and Taxes....................................     7
 
Financial Statements..................................................    10
 
Report of Independent Accountants.....................................    14
 
APPENDIX
 
Investment Manager....................................................   A-1
 
Trustees and Officers.................................................   A-7
 
Portfolio Transactions and Brokerage..................................  A-15
 
General Information...................................................  A-16
 
Custodian and Transfer Agent..........................................  A-16
 
Independent Accountants...............................................  A-17
 
Reports to Shareholders...............................................  A-17
 
Legal Counsel.........................................................  A-17
 
Experts...............................................................  A-17
 
Registration Statement................................................  A-17
 
Information with Respect to Securities Ratings........................  A-17
</TABLE>
    
 
                                       2
Active Assets Government Securities Trust
<PAGE>
INVESTMENT PRACTICES AND POLICIES
- --------------------------------------------------------------------------------
 
   
    REPURCHASE AGREEMENTS.  As discussed in the Prospectus, the Trust may  enter
into  repurchase  agreements  with  financial  institutions.  The  Trust follows
certain procedures,  adopted by  its Trustees,  designed to  minimize the  risks
inherent  in  such  agreements. These  procedures  include  effecting repurchase
transactions only with  large, well capitalized  and well established  financial
institutions  whose  financial  condition  will  be  continuously  monitored. In
addition, the value of the  collateral underlying the repurchase agreement  will
always  be at least  equal to the  resale price, which  consists of the purchase
price paid to the seller of the securities plus the accrued resale premium which
is defined as  the amount  specified in the  repurchase agreement  or the  daily
amortization  of the difference between the  purchase price and the resale price
specified in the repurchase agreement. Such collateral will consist entirely  of
securities  that are direct obligations  of, or that are  fully guaranteed as to
principal and  interest by,  the United  States or  any agency  thereof,  and/or
certificates  of deposit, bankers' acceptances which are eligible for acceptance
by a  Federal Reserve  Bank, and,  if the  seller is  a bank,  mortgage  related
securities  (as  such term  is  defined in  section  3(a)(41) of  the Securities
Exchange Act of 1934 that, at the time the repurchase agreement is entered into,
are rated in the highest rating category by the Requisite NRSROs.  Additionally,
the  collateral must qualify the repurchase agreement for preferential treatment
under the Federal Deposit Insurance Act  or the Federal Bankruptcy Code. In  the
event  of a default or bankruptcy by  a selling financial institution, the Trust
will seek to liquidate such collateral.  However, the exercising of the  Trust's
right to liquidate such collateral could involve certain costs or delays and, to
the  extent that  proceeds from  any sale  upon a  default of  the obligation to
repurchase were less than the repurchase  price, the Trust could suffer a  loss.
It  is the current  policy of the  Trust not to  invest in repurchase agreements
that do not mature within seven days  if any such investment, together with  any
other  illiquid assets held by the Trust, amounts  to more than 10% of its total
assets. The  Trust's  investments  in  repurchase agreements  may  at  times  be
substantial  when, in the  view of the Trust's  investment manager, liquidity or
other considerations warrant. For the fiscal year ended June 30, 1996, the Trust
did not enter into repurchase agreements in an amount exceeding 5% of its  total
net assets.
    
 
    REVERSE  REPURCHASE AGREEMENTS.   The Trust may  also use reverse repurchase
agreements as part of its investment strategy, but to date has not entered  into
nor  does it have  any intention of  entering into any  such agreements. Reverse
repurchase  agreements  involve   sales  by  the   Trust  of  portfolio   assets
concurrently  with an agreement by the Trust  to repurchase the same assets at a
later date at a fixed price. Generally, the effect of such a transaction is that
the Trust  can  recover all  or  most of  the  cash invested  in  the  portfolio
securities  involved during the term of  the reverse repurchase agreement, while
it will be  able to  keep the interest  income associated  with those  portfolio
securities.  Such transactions are only advantageous if the interest cost to the
Trust of the reverse repurchase transaction  is less than the cost of  otherwise
obtaining  the cash. Opportunities  to achieve this advantage  may not always be
available, and the Trust  intends to use the  reverse repurchase technique  only
when it will be to its advantage to do so. The Trust will establish a segregated
account  with  its  custodian  bank  in which  it  will  maintain  cash  or cash
equivalents or other portfolio securities equal in value to its obligations with
respect to  reverse repurchase  agreements.  Reverse repurchase  agreements  are
considered borrowings by the Trust.
 
    LENDING  OF PORTFOLIO  SECURITIES.   Subject to  investment restriction (11)
below, the Trust may lend portfolio securities to brokers, dealers and financial
institutions provided that cash equal  to at least 100%  of the market value  of
the  securities  loaned is  deposited  by the  borrower  with the  Trust  and is
maintained each  business day  in a  segregated account  pursuant to  applicable
regulations.  While such securities are on loan, the borrower will pay the Trust
any income accruing  thereon, and the  Trust may invest  the cash collateral  in
portfolio securities, thereby earning additional income. The Trust will not lend
its  portfolio  securities  if such  loans  are  not permitted  by  the  laws or
regulations of any state in which its shares are qualified for sale and will not
lend more than 10%  of the value  of its total  assets. The creditworthiness  of
firms  to which the Trust lends its portfolio securities will be monitored on an
ongoing basis. Loans would be subject to termination by the Trust in the  normal
settlement time, currently two business days after
 
                                       3
Active Assets Government Securities Trust
<PAGE>
   
notice,  or by  the borrower  on one day's  notice. Borrowed  securities must be
returned when the loan is  terminated. Any gain or loss  in the market price  of
the  borrowed securities which occurs during the  term of the loan inures to the
Trust and its  shareholders. The  Trust may pay  reasonable finders,  borrowers,
administrative,  and custodial fees in connection with a loan. During its fiscal
year ended June 30, 1996, the Trust did not lend any of its portfolio securities
and it has no intention of doing so in the foreseeable future.
    
 
    WHEN-ISSUED  AND  DELAYED  DELIVERY  SECURITIES.     As  discussed  in   the
Prospectus, from time to time, in the ordinary course of business, the Trust may
purchase  securities on a when-issued  or delayed delivery basis--i.e., delivery
and payment can take place  a month or more after  the date of the  transaction.
While  the  Trust will  only  purchase securities  on  a when-issued  or delayed
delivery basis with  the intention of  acquiring the securities,  the Trust  may
sell  the securities before the settlement date,  if it is deemed advisable. The
securities so  purchased or  sold  are subject  to  market fluctuations  and  no
interest  accrues to  the purchaser  during this period.  At the  time the Trust
makes the commitment to purchase securities on a when-issued or delayed delivery
basis, it will  record the transaction  and thereafter reflect  the value,  each
day,  of  such security  in  determining its  net asset  value.  At the  time of
delivery of the  securities, the value  may be  more or less  than the  purchase
price.  The Trust  will also establish  a segregated account  with its custodian
bank in  which it  will maintain  cash or  cash equivalents  or other  portfolio
securities  equal  in  value  to commitments  for  such  when-issued  or delayed
delivery securities.
 
    The foregoing strategies, and  those discussed in  the Prospectus under  the
heading  "Investment  Objectives and  Policies," may  subject  the Trust  to the
effects of interest rate  fluctuations to a greater  extent than would occur  if
such  strategies were not used. While the strategies listed above may be used by
the  Trust  if,  in  the  opinion  of  the  Investment  Manager,  they  will  be
advantageous  to the Trust,  the Trust will  be free to  reduce or eliminate its
activity in  any of  those  areas without  changing its  fundamental  investment
policies.  Certain provisions of the Internal Revenue Code, related regulations,
and rulings of the Internal Revenue Service may also have the effect of reducing
the extent to which the  previously cited techniques may  be used by the  Trust,
either  individually or in combination. Furthermore,  there is no assurance that
any of  these strategies  or  any other  strategies  and methods  of  investment
available to the Trust will result in the achievement of its objectives.
 
    The  Trust will attempt to balance  its objectives of security of principal,
high current  income  and  liquidity  by  investing  in  securities  of  varying
maturities  and risks. The Trust will not, however, invest in securities with an
effective maturity of more than one year. The amounts invested in obligations of
various maturities of one year or less will depend on management's evaluation of
the risks involved. Longer-term U.S.  Government issues, while generally  paying
higher  interest rates, are  subject to greater  fluctuations in value resulting
from general  changes in  interest rates  than shorter-term  issues. Thus,  when
rates  on  new  securities increase,  the  value of  outstanding  securities may
decline, and vice versa. Such changes may  also occur, to a lesser degree,  with
short-term  issues. These  changes, if realized,  may cause  fluctuations in the
amount of daily dividends and, in extreme cases, could cause the net asset value
per share to decline. In the  event of unusually large redemption demands,  such
securities  may have to be sold at a  loss prior to maturity, or the Trust might
have to  borrow  money  and  incur interest  expense.  Either  occurrence  would
adversely impact upon the amount of daily dividend and could result in a decline
in daily net asset value per share or the redemption by the Trust of shares held
in  a shareholder's account. The  Trust will attempt to  minimize these risks by
investing in relatively  longer-term securities  when it  appears to  management
that  yields on such securities are  not likely to increase substantially during
the period of expected  holding, and then only  in securities which are  readily
marketable. However, there can be no assurance that the Trust will be successful
in achieving this objective.
 
                                       4
Active Assets Government Securities Trust
<PAGE>
INVESTMENT RESTRICTIONS
- --------------------------------------------------------------------------------
 
    The  Trust  has  adopted  certain  investment  restrictions  as  fundamental
policies which  cannot be  changed without  the  approval of  the holders  of  a
"majority"  of the outstanding shares of the  Trust as defined in the Investment
Company Act of 1940, as amended (the  "Act"). Majority is defined in the Act  as
the lesser of (a) sixty-seven percent or more of the shares present at a meeting
of  shareholders, if the holders  of more than fifty  percent of the outstanding
shares of the Trust are present or represented by proxy, or (b) more than  fifty
percent of the outstanding shares of the Trust.
 
    These restrictions provide that the Trust may not:
 
        1.   Purchase  common stocks,  preferred stocks,  warrants, other equity
    securities, corporate  bond  debentures,  state bonds,  municipal  bonds  or
    industrial revenue bonds;
 
        2.    Borrow  money,  except  from  banks,  for  temporary  or emergency
    purposes, including the meeting of redemption requests which might otherwise
    require the untimely disposition of securities. Borrowing in the  aggregate,
    including  reverse repurchase agreements, may  not exceed 20%, and borrowing
    for purposes other than meeting redemptions  may not exceed 5% of the  value
    of   the  Trust's  total  assets   (including  the  amount  borrowed),  less
    liabilities (not including the amount borrowed) at the time the borrowing is
    made;
 
        3.   Pledge, hypothecate,  mortgage or  otherwise encumber  its  assets,
    except  in an amount up  to 10% of the  value of its net  assets but only to
    secure borrowings for temporary or emergency purposes;
 
        4.  Sell securities short or purchase securities on margin;
 
        5.  Write or purchase put or call options;
 
        6.  Underwrite the  securities of other  issuers or purchase  securities
    with contractual or other restrictions on resale;
 
        7.    Purchase  or  sell  real  estate,  real  estate  investment  trust
    securities, commodities or commodity contracts or oil and gas interests;
 
        8.  Make loans to others  except through the purchase of qualified  debt
    obligations,  loans  of  portfolio  securities  and  entry  into  repurchase
    agreements referred to under "Investment  Practices and Policies" above  and
    "Investment Objectives and Policies" in the Prospectus;
 
        9.   Issue senior securities as defined in the Act except insofar as the
    Trust may be  deemed to  have issued  a senior  security by  reason of:  (a)
    entering  into any repurchase or reverse repurchase agreement; (b) borrowing
    money in  accordance  with  restrictions described  above;  or  (c)  lending
    portfolio securities;
 
        10.  Invest in securities of other  investment companies, except as they
    may be acquired as part of a merger, consolidation or acquisition of assets;
    and
 
        11. Lend its portfolio securities in excess of 10% of its total  assets,
    taken  at value. Any loans of portfolio securities will be made according to
    guidelines established by the Trustees, including maintenance of  collateral
    of  the  borrower equal  at all  times to  the current  market value  of the
    securities loaned.
 
    If a percentage restriction is  adhered to at the  time of an investment,  a
later  increase or decrease in  percentage resulting from a  change in values of
portfolio securities or  amount of  total or net  assets will  not constitute  a
violation of such restriction.
 
                                       5
Active Assets Government Securities Trust
<PAGE>
HOW NET ASSET VALUE IS DETERMINED
- --------------------------------------------------------------------------------
 
    As  discussed in the Appendix to the  Prospectus, the net asset value of the
Trust is determined as of 12  noon New York time on  each day that the New  York
Stock  Exchange  is open.  The New  York Stock  Exchange currently  observes the
following holidays: New Year's Day; President's Day; Good Friday; Memorial  Day;
Independence Day; Labor Day; Thanksgiving Day; and Christmas Day.
 
    The  Trust  utilizes  the amortized  cost  method in  valuing  its portfolio
securities for purposes of determining the net asset value of the shares of  the
Trust.  The Trust  utilizes the amortized  cost method in  valuing its portfolio
securities even  though the  portfolio securities  may increase  or decrease  in
market  value,  generally, in  connection with  changes  in interest  rates. The
amortized cost  method of  valuation involves  valuing a  security at  its  cost
adjusted  by a  constant amortization  to maturity  of any  discount or premium,
regardless of the impact  of fluctuating interest rates  on the market value  of
the instrument. While this method provides certainty in valuation, it may result
in  periods during which  value, as determined  by amortized cost,  is higher or
lower than the price the Trust would  receive if it sold the instrument.  During
such  periods the yield to investors in  the Trust may differ somewhat from that
obtained in a  similar company  which uses  mark to  market values  for all  its
portfolio  securities. For example, if  the use of amortized  cost resulted in a
lower (higher)  aggregate portfolio  value on  a particular  day, a  prospective
investor  in the Trust would  be able to obtain  a somewhat higher (lower) yield
than would  result  from investment  in  such  a similar  company  and  existing
investors  would  receive less  (more) investment  income.  The purpose  of this
method of calculation is to facilitate  the maintenance of a constant net  asset
value per share of $1.00.
 
    The  Trust's  use  of  the  amortized cost  method  to  value  its portfolio
securities and the  maintenance of the  per share  net asset value  of $1.00  is
permitted  pursuant to Rule 2a-7 of the  Act (the "Rule"), and is conditioned on
its  compliance  with  various  conditions  including:  (a)  the  Trustees   are
obligated,  as a particular responsibility within  the overall duty of care owed
to the Trust's shareholders, to establish procedures reasonably designed, taking
into account current market conditions and the Trust's investment objectives, to
stabilize the  net  asset  value  per  share as  computed  for  the  purpose  of
distribution  and redemption at $1.00 per  share; (b) (i) the procedures include
calculation, at such intervals as the Trustees determine are appropriate and  as
are  reasonable in light of current market  conditions, of the deviation, if any
between net  asset value  per  share using  amortized  cost to  value  portfolio
securities  and  net  asset  value  per share  based  upon  available  of market
quotations with respect to  such portfolio securities;  (ii) periodic review  by
the Trustees of the amount of deviation as well as methods used to calculate it;
and  (iii)  maintenance  of written  records  of the  procedures,  the Trustees'
considerations  made  pursuant  to  them   and  any  actions  taken  upon   such
considerations;  (c) the Trustees should consider what steps should be taken, if
any, in the event of a difference of more than 1/2 of 1% between the two methods
of valuation;  and  (d)  the Trustees  should  take  such action  as  they  deem
appropriate  (such as shortening the average portfolio maturity, realizing gains
or losses or, as provided  by the Declaration of  Trust, reducing the number  of
the  outstanding  shares of  the Trust)  to  eliminate or  reduce to  the extent
reasonably practicable material dilution or other unfair results to investors or
existing shareholders. Any reduction of  outstanding shares will be effected  by
having  each shareholder proportionately  contribute to the  Trust's capital the
necessary shares that represent  the amount of  excess upon such  determination.
Each  shareholder will be  deemed to have  agreed to such  contribution in these
circumstances by  investment in  the Trust.  See "Dividends,  Distributions  and
Taxes" for a discussion of the tax effect of such a reduction.
 
    Generally,  for  purposes  of the  procedures  adopted under  the  Rule, the
maturity of  a  portfolio  instrument  is deemed  to  be  the  period  remaining
(calculated from the trade date or such other date on which the Trust's interest
in  the instrument is subject to market action) until the date noted on the face
of the instrument as the date on which the principal amount must be paid, or  in
the  case  of  an  instrument  called for  redemption,  the  date  on  which the
redemption payment must be made.
 
    A variable rate obligation that is subject to a demand feature is deemed  to
have  a maturity  equal to  the longer  of the  period remaining  until the next
readjustment   of    the    interest    rate    or    the    period    remaining
 
                                       6
Active Assets Government Securities Trust
<PAGE>
until  the principal  amount can  be recovered  through demand.  A floating rate
instrument that is  subject to a  demand feature  is deemed to  have a  maturity
equal  to  the period  remaining  until the  principal  amount can  be recovered
through demand.
 
   
    An Eligible Security generally is defined in the Rule to mean (i) A security
with a remaining  maturity of  397 calendar  days or  less that  has received  a
short-term  rating (or  that has been  issued by  an issuer that  has received a
short-term rating  with respect  to a  class of  debt obligations,  or any  debt
obligation  within that class, that is  comparable in priority and security with
the security)  by the  Requisite NRSROs  in one  of the  two highest  short-term
rating  categories  (within  which  there may  be  sub-categories  or gradations
indicating relative  standing); or  (ii) A  security: (A)  That at  the time  of
issuance  had a remaining maturity of more than 397 calendar days but that has a
remaining maturity  of 397  calendar days  or  less; and  (B) Whose  issuer  has
received  from the  Requisite NRSROs a  rating with  respect to a  class of debt
obligations (or any debt obligation within that class) that is now comparable in
priority and security with  the security, in one  of the two highest  short-term
rating  categories  (within  which  there may  be  sub-categories  or gradations
indicating  relative  standing);  or  (iii)  An  Unrated  Security  that  is  of
comparable  quality to a security meeting the requirements of (i) or (ii) above,
as determined by the money market fund's board of directors.
    
 
    As permitted by the Rule, the Board has delegated to the Trust's  Investment
Manager,  subject to the Board's oversight pursuant to guidelines and procedures
adopted by  the  Board, the  authority  to determine  which  securities  present
minimal  credit risks and which unrated  securities are comparable in quality to
rated securities.
 
    Also, as  required by  the Rule,  the Trust  will limit  its investments  in
securities,  other than Government securities, so that, at the time of purchase:
(a) except as further limited in (b) below with regard to certain securities, no
more than 5% of its total assets will  be invested in the securities of any  one
issuer;  and (b) with respect to Eligible Securities that have received a rating
in less than the  highest category by  any one of the  NRSROs whose ratings  are
used  to qualify the  security as an  Eligible Security, or  determined to be of
comparable quality: (i) no more  than 5% in the  aggregate of the Trust's  total
assets  in all such securities, and (ii) no more than the greater of 1% of total
assets, or $1 million, in the securities of any one issuer.
 
    If the Board determines that  it is no longer in  the best interests of  the
Trust  and its shareholders to maintain a stable price of $1 per share or if the
Board believes that maintaining such price no longer reflects a market-based net
asset value per share, the Board has the right to change from an amortized  cost
basis  of  valuation to  valuation based  on market  quotations. The  Trust will
notify shareholders of any such change.
 
    The  Rule  further  requires  that  the  Trust  limit  its  investments   to
instruments  which the Trustees determine present minimal credit risks. The Rule
also requires the Trust to maintain a dollar-weighted average portfolio maturity
(not more than 90 days) appropriate to its objective of maintaining a stable net
asset value of $1.00 per share and precludes the purchase of any instrument with
a remaining  maturity  of  more than  one  year.  Should the  disposition  of  a
portfolio  security result  in a  dollar-weighted average  portfolio maturity of
more than 90 days, the Trust is required to invest its available cash in such  a
manner  as to  reduce such  maturity to 90  days or  less as  soon as reasonably
practicable.
 
DIVIDENDS, DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------
 
    As discussed in the Appendix to the Prospectus, the Trust intends to declare
dividends payable on each day the New  York Stock Exchange is open for  business
of  all of its daily net investment  income and net short-term capital gains, if
any, to shareholders  of record as  of 12 Noon  New York time  of the  preceding
business  day. Net income, for dividend  purposes, includes accrued interest and
amortization of original issue and market discount, plus or minus any short-term
gains or losses realized on sales of
 
                                       7
Active Assets Government Securities Trust
<PAGE>
portfolio securities, less the amortization of market premium and the  estimated
expenses  of the Trust. Net  income will be calculated  immediately prior to the
determination of net asset value per share of the Trust.
 
    Gains or losses on the  sales of securities by  the Trust will be  long-term
capital  gains or losses if the securities have  been held by the Trust for more
than twelve months. Gains or  losses on the sale  of securities held for  twelve
months or less will be short-term capital gains or losses.
 
    The  Trustees may  revise the  dividend policy,  or postpone  the payment of
dividends, if the Trust should have or anticipate any large unexpected  expense,
loss  or fluctuation in net assets which,  in the opinion of the Trustees, might
have a significant  adverse effect  on shareholders.  On occasion,  in order  to
maintain  a constant $1.00  per share net  asset value, the  Trustees may direct
that the number of outstanding shares be reduced in each shareholder's  account.
Such  reduction may result in  taxable income to a  shareholder in excess of the
net  increase  (i.e.,  dividends,  less   such  reductions),  if  any,  in   the
shareholder's  account for a period. Furthermore, such reduction may be realized
as a capital loss when the shares are liquidated.
 
    The Trust  has qualified  and intends  to remain  qualified as  a  regulated
investment  company under Subchapter M of the  Internal Revenue Code of 1986, as
amended (the "Code"). If so qualified, the Trust will not be subject to  federal
income  and excise  taxes provided  that it distributes  all of  its taxable net
investment income and all of its net realized gains.
 
    Shareholders will be subject  to federal income tax  on dividends paid  from
interest income derived from taxable securities and on distributions of realized
net  short-term capital gains. Such interest and realized net short-term capital
gains dividends and  distributions are  taxable to the  shareholder as  ordinary
dividend   income   regardless  of   whether   the  shareholder   receives  such
distributions in  additional shares  or in  cash. Since  the Trust's  income  is
expected  to be  derived entirely from  interest rather than  dividends, none of
such dividends/distributions will be eligible for the federal dividends received
deduction available to corporations.
 
    The Code requires each regulated  investment company to pay a  nondeductible
4%  excise  tax to  the  extent the  company  does not  distribute,  during each
calendar year, 98% of its ordinary income, determined on a calendar year  basis,
and  98% of its capital gains, determined in  general on an October 31 year end,
plus certain undistributed  amounts from previous  years. The Trust  anticipates
that  it will  make sufficient timely  distributions to avoid  imposition of the
excise tax.
 
    Under  present  Massachusetts  law,  the   Trust  is  not  subject  to   any
Massachusetts  income tax during any fiscal year in which the Trust qualifies as
a regulated  investment company.  The Trust  might be  subject to  Massachusetts
income taxes for any taxable year in which it does not so qualify as a regulated
investment company.
 
    The  Trust may be  subject to tax or  taxes in certain  states where it does
business. Furthermore,  in those  states which  have income  tax laws,  the  tax
treatment  of the Trust and of shareholders with respect to distributions by the
Trust may differ from Federal tax treatment.
 
    Shareholders are urged to consult their own tax advisers regarding  specific
questions as to Federal, state or local taxes.
 
INFORMATION ON COMPUTATION OF YIELD
 
    The  Trust's annualized current yield, as may be quoted from time to time in
advertisements and other communications to shareholders and potential investors,
is computed  by determining,  for a  stated seven-day  period, the  net  change,
exclusive  of  capital  changes and  including  the value  of  additional shares
purchased with dividends  and any  dividends declared  therefrom (which  reflect
deductions  of all expenses of the Trust  such as management fees), in the value
of a hypothetical  pre-existing account  having a balance  of one  share at  the
beginning of the period, and dividing the difference by the value of the account
at  the beginning of the base period to  obtain the base period return, and then
multiplying the base period return by (365/7).
 
                                       8
Active Assets Government Securities Trust
<PAGE>
    The Trust's annualized effective yield, as  may be quoted from time to  time
in  advertisements  and  other  communications  to  shareholders  and  potential
investors, is computed by determining (for  the same stated seven-day period  as
for  the  current  yield), the  net  change,  exclusive of  capital  changes and
including the  value  of additional  shares  purchased with  dividends  and  any
dividends  declared therefrom (which  reflect deductions of  all expenses of the
Trust such as  management fees),  in the  value of  a hypothetical  pre-existing
account  having  a balance  of one  share at  the beginning  of the  period, and
dividing the difference by the value of the account at the beginning of the base
period to obtain the  base period return, and  then compounding the base  period
return  by adding 1, raising the  sum to a power equal  to 365 divided by 7, and
subtracting 1 from the result.
 
    The yields quoted in any advertisement or other communication should not  be
considered  a representation of the yields of  the Trust in the future since the
yield is not fixed. Actual yields will depend not only on the type, quality  and
maturities of the investments held by the Trust and changes in interest rates on
such investments, but also on changes in the Trust's expenses during the period.
 
    Yield  information may be  useful in reviewing the  performance of the Trust
and for providing  a basis  for comparison with  other investment  alternatives.
However,  unlike bank deposits or other  investments which typically pay a fixed
yield for a stated period of time, the Trust's yield fluctuates.
 
   
    The Trust's current yield for the seven days ended June 30, 1996 was  4.67%.
The effective annual yield on 4.67% is 4.78%, assuming daily compounding.
    
 
                                       9
Active Assets Government Securities Trust
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
STATEMENT OF ASSETS AND LIABILITIES
JUNE 30, 1996
- --------------------------------------------------------------------------------
 
<TABLE>
<S>                                         <C>
ASSETS:
Investments in securities, at value
  (amortized cost $571,666,258)...........  $ 571,666,258
Cash......................................         90,000
Interest receivable.......................             93
Prepaid expenses and other assets.........         21,226
                                            -------------
        TOTAL ASSETS......................    571,777,577
                                            -------------
LIABILITIES:
Payable for:
  Investment management fee...............        220,885
  Plan of distribution fee................         45,223
  Shares of beneficial interest
    repurchased...........................             92
Accrued expenses and other payables.......        111,289
                                            -------------
        TOTAL LIABILITIES.................        377,489
                                            -------------
NET ASSETS:
Paid-in-capital...........................    571,399,751
Accumulated undistributed net investment
  income..................................            337
                                            -------------
        NET ASSETS........................  $ 571,400,088
                                            -------------
                                            -------------
NET ASSET VALUE PER SHARE, 571,399,751
 shares outstanding (unlimited shares
 authorized of $.01 par value)............
                                                    $1.00
                                            -------------
                                            -------------
</TABLE>
 
STATEMENT OF OPERATIONS
FOR THE YEAR ENDED JUNE 30, 1996
 
   
<TABLE>
<S>                                          <C>
NET INVESTMENT INCOME:
INTEREST INCOME............................  $32,406,748
                                             -----------
EXPENSES
  Investment management fee................    2,841,130
  Plan of distribution fee.................      570,309
  Transfer agent fees and expenses.........      121,843
  Registration fees........................      110,736
  Professional fees........................       45,683
  Shareholder reports and notices..........       37,493
  Custodian fees...........................       33,551
  Trustees' fees and expenses..............       17,577
  Other....................................        8,619
                                             -----------
      TOTAL EXPENSES.......................    3,786,941
                                             -----------
      NET INVESTMENT INCOME AND NET
       INCREASE............................  $28,619,807
                                             -----------
                                             -----------
</TABLE>
    
 
STATEMENT OF CHANGES IN NET ASSETS
- --------------------------------------------------------------------------------
 
<TABLE>
<CAPTION>
                                                                           FOR THE YEAR ENDED  FOR THE YEAR ENDED
                                                                             JUNE 30, 1996       JUNE 30, 1995
                                                                           ------------------  ------------------
<S>                                                                        <C>                 <C>
INCREASE (DECREASE) IN NET ASSETS:
  Operations:
    Net investment income and net increase...............................    $   28,619,807      $   25,276,044
    Dividends from net investment income.................................       (28,619,562)        (25,276,526)
    Net increase from transactions in shares of beneficial interest......        29,180,773          70,718,948
                                                                           ------------------  ------------------
        Total increase...................................................        29,181,018          70,718,466
NET ASSETS:
  Beginning of period....................................................       542,219,070         471,500,604
                                                                           ------------------  ------------------
  END OF PERIOD (including undistributed net investment income of $337
   and $92, respectively)................................................    $  571,400,088      $  542,219,070
                                                                           ------------------  ------------------
                                                                           ------------------  ------------------
</TABLE>
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       10
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
1.   ORGANIZATION  AND ACCOUNTING POLICIES--Active  Assets Government Securities
Trust (the "Trust") is registered under  the Investment Company Act of 1940,  as
amended  (the "Act"), as a  diversified, open-end management investment company.
The Trust's  investment  objectives are  high  current income,  preservation  of
capital and liquidity. The Trust was organized as a Massachusetts business trust
on March 30, 1981 and commenced operations on July 7, 1981.
 
    The  preparation  of  financial  statements  in  accordance  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that affect  the reported  amounts and  disclosures. Actual results
could differ from  those estimates. The  following is a  summary of  significant
accounting policies:
 
    A.   VALUATION OF INVESTMENTS--Portfolio  securities are valued at amortized
    cost, which approximates market value.
 
    B.  ACCOUNTING FOR INVESTMENTS--Security  transactions are accounted for  on
    the  trade date (date the order to  buy or sell is executed). Realized gains
    and losses on security  transactions are determined  by the identified  cost
    method. The Trust amortizes premiums and accretes discounts over the life of
    the respective securities. Interest income is accrued daily.
 
    C.   FEDERAL INCOME TAX STATUS--It is  the Trust's policy to comply with the
    requirements of the Internal Revenue Code applicable to regulated investment
    companies and to distribute all of its taxable and nontaxable income to  its
    shareholders. Accordingly, no federal income tax provision is required.
 
    D.  DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS--The Trust records dividends
    and distributions to shareholders as of the close of each business day.
 
2.    INVESTMENT  MANAGEMENT  AGREEMENT--Pursuant  to  an  Investment Management
Agreement with Dean  Witter InterCapital  Inc. (the  "Investment Manager"),  the
Trust  pays the Investment  Manager a management fee,  accrued daily and payable
monthly, by applying the following annual rates  to the net assets of the  Trust
determined  as of the close of each business  day: 0.50% to the portion of daily
net assets not exceeding $500 million; 0.425% to the portion of daily net assets
exceeding $500 million but not exceeding $750 million; 0.375% to the portion  of
daily  net assets exceeding $750 million but  not exceeding $1 billion; 0.35% to
the portion of  daily net  assets exceeding $1  billion but  not exceeding  $1.5
billion;  0.325% to the portion  of daily net assets  exceeding $1.5 billion but
not exceeding $2 billion; 0.30% to the portion of daily net assets exceeding  $2
billion  but not  exceeding $2.5  billion; 0.275%  to the  portion of  daily net
assets exceeding $2.5  billion but not  exceeding $3 billion;  and 0.25% to  the
portion of daily net assets exceeding $3 billion.
 
    Under  the  terms of  the  Agreement, in  addition  to managing  the Trust's
investments, the Investment Manager maintains  certain of the Trust's books  and
records  and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain  legal services and pays  the salaries of  all
personnel,  including officers of the Trust  who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Trust.
 
3.  PLAN OF DISTRIBUTION--Dean Witter Distributors Inc. (the "Distributor"),  an
affiliate  of the Investment  Manager, is the distributor  of the Trust's shares
and, in accordance  with a Plan  of Distribution (the  "Plan") pursuant to  Rule
12b-1 under the Act, finances certain expenses in connection therewith.
 
                                       11
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS JUNE 30, 1996 (CONTINUED)
- --------------------------------------------------------------------------------
 
    Under  the Plan,  the Distributor bears  the expense of  all promotional and
distribution related activities on behalf of the Trust, except for expenses that
the  Trustees  determine  to  reimburse,  as  described  below.  The   following
activities   and  services  may  be  provided   by  the  Distributor  and  other
broker-dealers under  the  Plan:  (1)  compensation to,  and  expenses  of,  the
Distributor  and other broker-dealers; (2) sales incentives and bonuses to sales
representatives and to marketing personnel in connection with promoting sales of
the Trust's shares; (3) expenses incurred in connection with promoting sales  of
the  Trust's shares;  (4) preparing and  distributing sales  literature; and (5)
providing  advertising  and  promotional   activities,  including  direct   mail
solicitation   and  television,  radio,  newspaper,  magazine  and  other  media
advertisements.
 
    The Trust is authorized to  reimburse the Distributor for specific  expenses
the  Distributor incurs or plans  to incur in promoting  the distribution of the
Trust's shares. The amount of each monthly reimbursement payment may in no event
exceed an amount equal to a payment at  the annual rate of 0.15% of the  Trust's
average  daily net assets during the month. Expenses incurred by the Distributor
pursuant to the  Plan in any  fiscal year will  not be reimbursed  by the  Trust
through  payments accrued in any subsequent fiscal year. For the year ended June
30, 1996, the distribution fee was accrued at the annual rate of 0.10%.
 
4.    SECURITY  TRANSACTIONS  AND  TRANSACTIONS  WITH  AFFILIATES--The  cost  of
purchases  and proceeds  from sales/maturities  of portfolio  securities for the
year  ended  June  30,   1996  aggregated  $7,798,198,359  and   $7,800,002,083,
respectively.
 
    Dean  Witter  Trust  Company, an  affiliate  of the  Investment  Manager and
Distributor, is the  Trust's transfer  agent. At June  30, 1996,  the Trust  had
transfer agent fees and expenses payable of approximately $8,800.
 
    The  Trust  has an  unfunded  noncontributory defined  benefit  pension plan
covering all  independent  Trustees  of  the  Trust  who  will  have  served  as
independent Trustees for at least five years at the time of retirement. Benefits
under  this plan are based on years  of service and compensation during the last
five years of service. Aggregate pension costs for the year ended June 30,  1996
included  in Trustees' fees and expenses in the Statement of Operations amounted
to $1,096. At  June 30,  1996, the  Trust had  an accrued  pension liability  of
$48,883  which is included  in accrued expenses  in the Statement  of Assets and
Liabilities.
 
5.    SHARES  OF  BENEFICIAL  INTEREST--Transactions  in  shares  of  beneficial
interest, at $1.00 per share, were as follows:
 
   
<TABLE>
<CAPTION>
                                                                                     FOR THE YEAR       FOR THE YEAR
                                                                                         ENDED              ENDED
                                                                                     JUNE 30, 1996      JUNE 30, 1995
                                                                                   -----------------  -----------------
<S>                                                                                <C>                <C>
Shares sold......................................................................     2,060,055,907      1,974,285,922
Shares issued in reinvestment of dividends.......................................        28,586,199         25,245,423
                                                                                   -----------------  -----------------
                                                                                      2,088,642,106      1,999,531,345
Shares repurchased...............................................................    (2,059,461,333)    (1,928,812,397)
                                                                                   -----------------  -----------------
Net increase in shares outstanding...............................................        29,180,773         70,718,948
                                                                                   -----------------  -----------------
                                                                                   -----------------  -----------------
</TABLE>
    
 
6.   SELECTED PER SHARE DATA AND RATIOS--See the "Financial Highlights" table on
page 3 of this Prospectus.
 
                                       12
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
PORTFOLIO OF INVESTMENTS JUNE 30, 1996
- --------------------------------------------------------------------------------
 
   
<TABLE>
<CAPTION>
                                                                                              ANNUALIZED
 PRINCIPAL                                                                                      YIELD
AMOUNT (IN                                  DESCRIPTION AND                                   ON DATE OF
THOUSANDS)                                   MATURITY DATES                                    PURCHASE        VALUE
- -----------  ------------------------------------------------------------------------------  ------------  -------------
<C>          <S>                                                                             <C>           <C>
             U.S. GOVERNMENT AGENCIES (99.1%)
 $ 101,925   Federal Farm Credit Bank
               07/11/96 - 12/02/96.........................................................  4.86 - 5.55%  $ 100,763,284
   220,240   Federal Home Loan Banks
               07/01/96 - 12/17/96.........................................................  4.95 - 5.54     217,770,349
   113,336   Federal Home Loan Mortgage Corp.
               07/03/96 - 09/27/96.........................................................  5.22 - 5.42     112,502,650
   119,555   Federal National Mortgage Assoc.
               07/03/96 - 10/11/96.........................................................  4.99 - 5.42     118,583,575
     7,000   Student Loan Marketing Assoc.
               07/01/96....................................................................      5.52          6,997,853
    10,000   Tennessee Valley Authority
               08/29/96....................................................................      5.37          9,910,025
                                                                                                           -------------
             TOTAL U.S. GOVERNMENT AGENCIES (AMORTIZED COST $566,527,736)................................    566,527,736
                                                                                                           -------------
             U.S. GOVERNMENT OBLIGATION (0.9%)
     5,000   U.S. Treasury Bill 10/17/96 (Amortized Cost $4,919,945).........................        5.53         4,919,945
                                                                                                              -------------
             REPURCHASE AGREEMENT (0.1%)
       219   The Bank of New York due 07/01/96 (dated 06/28/96; proceeds $218,670;
               collateralized by $146,249 U.S. Treasury Note due 07/31/98 valued at $146,876
               and $76,368 U.S. Treasury Note due 11/30/97 valued at $76,073) (Identified
               Cost $218,577)................................................................       5.125           218,577
                                                                                                              -------------
             TOTAL INVESTMENTS (AMORTIZED COST $571,666,258) (A).............................       100.1%      571,666,258
             LIABILITIES IN EXCESS OF CASH AND OTHER ASSETS..................................        (0.1)         (266,170)
                                                                                                   ------     -------------
             NET ASSETS......................................................................       100.0%    $ 571,400,088
                                                                                                   ------     -------------
                                                                                                   ------     -------------
</TABLE>
    
 
- ------------
(A) COST IS THE SAME FOR FEDERAL INCOME TAX PURPOSES.
 
                       SEE NOTES TO FINANCIAL STATEMENTS
 
                                       13
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
To the Shareholders and Trustees of Active Assets Government Securities Trust
 
In  our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments,  and the related statements  of operations and  of
changes  in  net assets  and the  financial highlights  (which appear  under the
heading "Financial Highlights" on page 3 of this Prospectus) present fairly,  in
all  material  respects,  the  financial position  of  Active  Assets Government
Securities Trust (the "Trust") at June  30, 1996, the results of its  operations
for the year then ended, the changes in its net assets for each of the two years
in  the period then ended and the financial highlights for each of the ten years
in the  period then  ended,  in conformity  with generally  accepted  accounting
principles.  These  financial  statements  and  financial  highlights (hereafter
referred to as  "financial statements")  are the responsibility  of the  Trust's
management;  our  responsibility is  to express  an  opinion on  these financial
statements based  on our  audits. We  conducted our  audits of  these  financial
statements  in  accordance  with  generally  accepted  auditing  standards which
require that we plan and perform the audit to obtain reasonable assurance  about
whether  the financial  statements are free  of material  misstatement. An audit
includes examining,  on  a  test  basis, evidence  supporting  the  amounts  and
disclosures  in the  financial statements,  assessing the  accounting principles
used and significant estimates  made by management,  and evaluating the  overall
financial  statement presentation.  We believe  that our  audits, which included
confirmation  of  securities  at  June  30,  1996  by  correspondence  with  the
custodian, provide a reasonable basis for the opinion expressed above.
 
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 7, 1996
 
                                       14
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
<PAGE>
APPENDIX
- --------------------------------------------------------------------------------
 
    This  Appendix constitutes part of  the Statements of Additional Information
of the Active Assets Money Trust (the "Money Trust"), the Active Assets Tax-Free
Trust (the "Tax-Free Trust"), the  Active Assets California Tax-Free Trust  (the
"California  Tax-Free Trust") and the  Active Assets Government Securities Trust
(the "Government Securities Trust").  The Money Trust,  the Tax-Free Trust,  the
California Tax-Free Trust and the Government Securities Trust are referred to in
this  Appendix  collectively as  the "Trusts".  Unless otherwise  indicated, the
information set forth herein is applicable to each Trust.
 
INVESTMENT MANAGER
- --------------------------------------------------------------------------------
 
    Dean Witter InterCapital Inc. (the "Investment Manager" or  "InterCapital"),
a  Delaware corporation, whose address is Two  World Trade Center, New York, New
York 10048, is the  Trusts' Investment Manager.  InterCapital is a  wholly-owned
subsidiary  of Dean Witter, Discover &  Co. ("DWDC") a Delaware corporation. The
daily management of the Trusts and  research relating to the Trusts'  portfolios
is  conducted by  or under the  direction of officers  of the Trusts  and of the
Investment Manager, subject to review of investments by the Trusts' Trustees. In
addition, Trustees  of  the Trusts  provide  guidance on  economic  factors  and
interest rate trends. Information as to these Trustees and Officers is contained
under the caption "Trustees and Officers."
 
   
    InterCapital  also serves as  investment manager (or  investment advisor and
administrator) of the following investment  companies: Dean Witter Liquid  Asset
Fund   Inc.,  InterCapital  Income  Securities  Inc.,  Dean  Witter  High  Yield
Securities Inc., Dean Witter Tax-Free Daily Income Trust, Dean Witter Developing
Growth Securities Trust,  Dean Witter Tax-Exempt  Securities Trust, Dean  Witter
American  Value Fund, Dean  Witter Dividend Growth  Securities Inc., Dean Witter
Natural Resource Development Securities Inc., Dean Witter U.S. Government  Money
Market  Trust, Dean  Witter Variable Investment  Series, Dean  Witter World Wide
Investment Trust, Dean  Witter Select Municipal  Reinvestment Fund, Dean  Witter
U.S.  Government Securities Trust, Dean  Witter California Tax-Free Income Fund,
Dean Witter New York  Tax-Free Income Fund,  Dean Witter Convertible  Securities
Trust,  Dean  Witter Federal  Securities Trust,  Dean Witter  Value-Added Market
Series, High Income Advantage Trust, High Income Advantage Trust II, Dean Witter
Government Income  Trust, Dean  Witter Utilities  Fund, Dean  Witter  California
Tax-Free Daily Income Trust, Dean Witter Strategist Fund, Dean Witter World Wide
Income  Trust,  High  Income Advantage  Trust  III, Dean  Witter  Capital Growth
Securities, Dean  Witter  European  Growth  Fund, Inc.,  Dean  Witter  New  York
Municipal  Money Market Trust,  Dean Witter Precious  Metals and Minerals Trust,
Dean Witter Global Short-Term Income Fund Inc., Dean Witter Pacific Growth  Fund
Inc.,  Dean  Witter  Multi-State Municipal  Series  Trust,  InterCapital Insured
Municipal Bond Trust, InterCapital Insured Municipal Trust, InterCapital Quality
Municipal Investment Trust, Dean  Witter Diversified Income Trust,  InterCapital
Quality Municipal Income Trust, InterCapital California Insured Municipal Income
Trust,  Dean Witter Global Dividend Growth  Securities, Dean Witter Limited Term
Municipal Trust,  Dean  Witter Health  Sciences  Trust, Dean  Witter  Retirement
Series,  Dean Witter Premier Income Trust,  Dean Witter Short-Term U.S. Treasury
Trust,  InterCapital  Quality  Municipal  Securities,  InterCapital   California
Quality   Municipal   Securities,  InterCapital   New  York   Quality  Municipal
Securities, InterCapital Insured  Municipal Income  Trust, InterCapital  Insured
Municipal Securities, InterCapital Insured California Municipal Securities, Dean
Witter  Short-Term Bond  Fund, Dean  Witter Global  Utilities Fund,  Dean Witter
National Municipal  Trust,  Dean  Witter High  Income  Securities,  Dean  Witter
International  SmallCap  Fund,  Dean  Witter Mid-Cap  Growth  Fund,  Dean Witter
Intermediate Income Securities, Dean Witter Select Dimensions Investment Series,
Dean Witter Balanced Growth Fund, Dean Witter Balanced Income Fund, Dean  Witter
Hawaii Municipal Trust, Municipal Income Trust, Dean Witter Capital Appreciation
Fund, Dean Witter Intermediate Term U.S. Treasury Trust, Dean Witter Information
Fund,  Dean Witter Japan Fund, Dean Witter Income Builder Fund, Municipal Income
Trust II,  Municipal Income  Trust III,  Municipal Income  Opportunities  Trust,
Municipal  Income Opportunities Trust  II, Prime Income  Trust, Municipal Income
Opportunities Trust  III  and  Municipal Premium  Income  Trust.  The  foregoing
investment  companies, together with the Trusts, are collectively referred to as
the Dean Witter Funds. In addition, Dean Witter Services Company Inc.  ("DWSC"),
a   wholly-owned  subsidiary  of   InterCapital,  serves  as   manager  for  the
    
 
                                      A-1
<PAGE>
   
following investment  companies, for  which TCW  Funds Management,  Inc. is  the
investment  adviser: TCW/DW Core Equity  Trust, TCW/DW North American Government
Income Trust, TCW/DW Latin American Growth Fund, TCW/DW Term Trust 2002,  TCW/DW
Income  and Growth  Fund, TCW/DW  Small Cap  Growth Fund,  TCW/DW Balanced Fund,
TCW/DW Total Return Trust,  TCW/DW Mid-Cap Equity  Trust, TCW/DW Global  Telecom
Fund,  TCW/DW Term Trust 2000  and TCW/DW Term Trust  2003 (the "TCW/DW Funds").
InterCapital also serves as: (i)  sub-adviser to Templeton Global  Opportunities
Trust,  an  open-end investment  company;  (ii) administrator  of  The BlackRock
Strategic  Term  Trust  Inc.,  a   closed-end  investment  company;  and   (iii)
sub-administrator  of  MassMutual Participation  Investors and  Templeton Global
Governments Income Trust, closed-end investment companies.
    
 
    The Trusts have entered into separate Investment Management Agreements  (the
"Agreements")  with  the Investment  Manager.  Pursuant to  the  Agreements, the
Trusts have retained the Investment Manager to manage the investment of each  of
the Trusts' assets, including the placing of orders for the purchase and sale of
portfolio   securities.  The  Investment  Manager  obtains  and  evaluates  such
information and advice relating to the economy, securities markets, and specific
securities as it considers necessary or useful to continuously manage the assets
of the  Trusts in  a  manner consistent  with  their investment  objectives  and
policies.
 
    Under  the  terms of  the Agreements,  in addition  to managing  the Trusts'
investments, the Investment Manager maintains  certain of the Trusts' books  and
records  and  furnishes,  at its  own  expense, such  office  space, facilities,
equipment, clerical help and bookkeeping  services as the Trusts may  reasonably
require in the conduct of business. In addition, the Investment Manager pays the
salaries of all personnel, including officers of the Trusts who are employees of
the  Investment Manager. The Investment Manager also bears the cost of telephone
service, heat,  light,  power  and  other  utilities  provided  to  the  Trusts.
Effective   December  31,  1993,  pursuant   to  a  Services  Agreement  between
InterCapital and DWSC, DWSC began to provide the administrative services to  the
Trusts  which were previously  performed directly by  InterCapital. On April 17,
1995, DWSC was  reorganized in the  State of Delaware,  necessitating the  entry
into  a  new Services  Agreement  by InterCapital  and  DWSC on  such  date. The
foregoing internal reorganizations did not result in any change in the nature or
scope of the administrative services  being provided to the  Fund or any of  the
fees  being paid by the Fund for  the overall services being performed under the
terms of the existing Management Agreement.
 
    Expenses not expressly assumed  by the Investment Manager  under any of  the
Agreements   or  by  Dean   Witter  Distributors  Inc.   ("Distributors  or  the
Distributor"), the Distributor of the Trusts' shares (see "Plan and Agreement of
Distribution" below and  in the  Prospectus), will be  paid by  the Trusts.  The
expenses  borne  by the  Trusts include,  but  are not  limited to:  charges and
expenses of any  registrar, custodian,  stock transfer  and dividend  disbursing
agent;  brokerage commissions; taxes; engraving and printing share certificates,
if any; registration  costs of  the Trusts and  their shares  under federal  and
state  securities laws; the cost and expense of printing, including typesetting,
and distributing prospectuses  and statements of  additional information of  the
Trusts  and supplements  thereto to  the Trusts'  shareholders; all  expenses of
shareholders' and Trustees' meetings and  of preparing, printing and mailing  of
proxy  statements  and  reports to  shareholders;  fees and  travel  expenses of
Trustees or members of any advisory board or committee who are not employees  of
the Investment Manager or any corporate affiliate of the Investment Manager; all
expenses incident to any dividend, withdrawal or redemption options; charges and
expenses  of  any outside  service  used for  pricing  of the  Trusts' portfolio
securities; fees  and  expenses  of  legal counsel,  including  counsel  to  the
Trustees  who are  not interested  persons of  the Trusts  or of  the Investment
Manager and independent accountants;  membership dues of industry  associations;
interest  on  Trust  borrowings;  postage;  insurance  premiums  on  property or
personnel (including officers  and trustees) of  the Trusts which  inure to  the
Trusts'  benefit; extraordinary expenses  (including, but not  limited to, legal
claims and liabilities  and litigation  costs and  any indemnification  relating
thereto); and all other costs of the Trusts' operation.
 
    As full compensation for the services and facilities furnished to the Trusts
and  Trust expenses assumed by  the Investment Manager, the  Trusts each pay the
Investment  Manager  monthly  compensation  calculated  daily  by  applying  the
following   annual  rates   to  the   net  assets   of  the   respective  Trust,
 
                                      A-2
<PAGE>
   
determined as of the  close of each  business day: 0.50% of  the portion of  the
daily  net assets not exceeding $500 million; 0.425% of the portion of the daily
net assets exceeding $500 million but not exceeding $750 million; 0.375% of  the
portion  of the  daily net  assets exceeding $750  million but  not exceeding $1
billion; 0.35% of the portion of the  daily net assets exceeding $1 billion  but
not  exceeding  $1.5 billion;  0.325% of  the  portion of  the daily  net assets
exceeding $1.5 billion but not exceeding $2 billion; 0.3% of the portion of  the
daily  net assets exceeding $2 billion but not exceeding $2.5 billion; 0.275% of
the portion of the daily net assets exceeding $2.5 billion but not exceeding  $3
billion;  and 0.25% of the portion of the daily net assets exceeding $3 billion.
The Money Trust accrued to the Investment Manager compensation in the amounts of
$13,025,495, $15,638,717 and $19,802,633 during the fiscal years ended June  30,
1994,  June 30, 1995 and June 30, 1996, respectively. The Tax-Free Trust accrued
to the Investment Manager compensation in the amounts of $6,138,744,  $6,276,658
and  $6,571,351 for the fiscal years ended June 30, 1994, June 30, 1995 and June
30, 1996, respectively. The California Tax-Free Trust accrued to the  Investment
Manager compensation in the amounts of $1,328,271, $1,502,742 and $1,781,282 for
the  fiscal  years  ended  June 30,  1994,  June  30, 1995  and  June  30, 1996,
respectively. The Government Securities Trust accrued to the Investment  Manager
compensation  in the  amounts of $2,594,882,  $2,595,218 and  $2,841,130 for the
fiscal years ended June 30, 1994, June 30, 1995 and June 30, 1996, respectively.
    
 
   
    Under the Agreements, total operating  expenses of each Trust, exclusive  of
taxes,  interest,  brokerage  fees  and extraordinary  expenses  (to  the extent
permitted by applicable state securities  laws and regulations), are subject  to
applicable limitations under rules and regulations of states where each Trust is
authorized  to sell its shares. Therefore, such expenses are effectively subject
to the most restrictive of such limitations as the same may be amended from time
to time. Presently, the most restrictive limitation is as follows: 2 1/2% of the
first $30,000,000 of  average daily net  assets, 2% of  the next $70,000,000  of
average  daily net assets and 1 1/2%  of any excess over $100,000,000 of average
daily net assets.  Under the Agreements,  if in any  fiscal year such  operating
expenses  exceed  this limitation,  the  Investment Manager  will  reimburse the
Trust(s) for the amount of such excess. Such amount, if any, will be  calculated
daily  and credited on a  monthly basis. During the  fiscal years ended June 30,
1994, June 30, 1995  and June 30,  1996, the expenses  of Money Trust,  Tax-Free
Trust,  California Tax-Free Trust and Government Securities Trust did not exceed
this limitation or the then existing most restrictive limitation.
    
 
    The Agreements  provide that  in  the absence  of willful  misfeasance,  bad
faith, gross negligence or reckless disregard of its obligations thereunder, the
Investment Manager is not liable to the Trusts or any of their investors for any
act  or omission by  the Investment Manager  or for any  losses sustained by the
Trusts or their  investors. The  Agreements in  no way  restrict the  Investment
Manager from acting as investment manager or adviser to others.
 
    The Agreements between Money Trust, Tax-Free Trust and Government Securities
Trust  and the  Investment Manager  were initially  approved by  the Trustees on
January 18, 1983 and were approved by the shareholders of the respective  Trusts
on  March 17, 1983 and March 18, 1983. Pursuant to their terms, these Agreements
remained in effect until October 31, 1984  and were continued from year to  year
thereafter,  as the continuance of each Agreement was approved at least annually
by the vote of a majority, as defined in the Investment Company Act of 1940 (the
"Act"), of the outstanding voting securities of the Trust or by the Trustees  of
the  Trust, provided that in either event such continuance was approved annually
by the vote of a majority of the Trustees who were not parties to the  Agreement
or  "interested  persons"  (as defined  in  the  Act) of  any  such  party ("the
Independent Trustees"), which vote  was cast in person  at a meeting called  for
the purpose of voting on such approval.
 
    At  their meeting held on April 29,  1992, which was specifically called for
the purpose of voting on the approval of the continuance of the Agreements,  the
Trustees,  including  a majority  of  the non-interested  Trustees  as described
above, voted to  continue the  current Agreements  until April  30, 1993.  These
Agreements  may  be terminated  at any  time, without  penalty, on  thirty days'
notice, by the Trustees of the Trust,  by the holders of a majority, as  defined
in  the  Act,  of  the  Trust's shares,  or  by  the  Investment  Manager. These
Agreements will automatically  terminate in  the event of  their assignment  (as
defined in the Act).
 
                                      A-3
<PAGE>
   
    At  their meetings held on October 30,  1992, the Trustees, including all of
the  Independent  Trustees,  of  Money  Trust,  Tax-Free  Trust  and  Government
Securities Trust approved the assumption of the rights and duties of Dean Witter
(InterCapital's  predecessor  as  the  Trust's  Investment  Manager)  under  the
Agreements by  InterCapital, upon  the internal  reorganization of  Dean  Witter
Reynolds  Inc.  ("Dean Witter")  (which  reorganization took  place  in January,
1993). At the  same meetings,  the Trustees approved  new investment  management
agreements  to take effect upon the spin-off by Sears, Roebuck and Co. ("Sears")
of its remaining shares of DWDC. This spin-off was consummated on June 30, 1993,
whereupon  the  new  agreements  took  effect.  The  new  investment  management
agreements   are  substantially  identical  in  all  material  respects  to  the
Agreements. The  approvals of  the Trustees  were subsequently  ratified by  the
shareholders  of  Money Trust,  Tax-Free  Trust Government  Securities  Trust at
Special Meetings held on January 12, 1993. Subsequently, at their meetings  held
on  April 17,  1996, the  Trustees approved the  most recent  continuance of the
Agreements until April 30, 1997.
    
 
    The Agreement between California Tax-Free  Trust and the Investment  Manager
was  approved by the  Trustees on July 18,  1991 and by Dean  Witter as the sole
shareholder on October  4, 1991.  Under its  terms, this  Agreement remained  in
effect  until April  30, 1993,  and will  continue in  effect from  year to year
thereafter, provided continuance of each Agreement is approved at least annually
by the vote  of a majority,  as defined in  the Act, of  the outstanding  voting
securities of the Trust or by the Trustees of the Trust, provided that in either
event  such continuance is  approved annually by  the vote of  a majority of the
Independent Trustees of the California Tax-Free  Trust, which vote must be  cast
in  person at a meeting called for the  purpose of voting on such approval. This
Agreement may,  be terminated  at any  time, without  penalty, on  thirty  day's
notice,  by the Trustees of  the California Tax-Free Trust,  by the holders of a
majority, as defined in the Act,  of the California Tax-Free Trust's shares,  or
by  the Investment  Manager. The Agreement  will automatically  terminate in the
event of its assignment (as defined in the Act).
 
   
    At its meeting held on October 30, 1992, the Trustees of California Tax-Free
Trust, including all  of the  Independent Trustees, approved  the assumption  by
InterCapital  of  Dean Witter's  rights and  duties  under the  Agreement (which
assumption took  place upon  the reorganization  referred to  above, and  a  new
investment  management  agreement  identical  in all  material  respects  to the
Agreement) to take effect  upon the spin-off described  above. At their  Special
Meeting  held on January 13, 1993, the shareholders of California Tax-Free Trust
approved the Agreement's continuation as  well as the aforementioned  assumption
of  rights and  duties and the  new investment management  agreement (which went
into effect on June 30, 1993). Subsequently, at their meetings held on April 17,
1996, the Trustees approved the most  recent continuance of the Agreement  until
April 30, 1997.
    
 
    The   Investment  Manager  has  paid  the  organizational  expenses  of  the
California Tax-Free Trust  incurred prior  to the  offering of  its shares.  The
California  Tax-Free  Trust  has  reimbursed  the  Investment  Manager  for such
expenses in an amount  of approximately $46,500.  The California Tax-Free  Trust
has  deferred and  is amortizing  the reimbursed  expenses on  the straight line
method over a period not to exceed  five years from the date of commencement  of
its operations.
 
PLAN OF DISTRIBUTION
 
    As  discussed in the Prospectus, each  Trust has entered into a Distribution
Agreement with Dean Witter Distributors  Inc. (the "Distributor") in  connection
with  the  continuous offering  of  the shares  of  the Trust.  The Distribution
Agreements obligate the Distributor to  pay certain expenses in connection  with
the  offering  of the  shares  of the  Trust,  including costs  involved  in the
distribution of  prospectuses and  periodic reports  to investors,  the cost  of
other supplementary sales literature and advertising costs.
 
    The  Distributor  has  entered  into selected  dealer  agreements  with Dean
Witter, which through its own sales organization sells shares of the Trusts. The
Distributor, a Delaware corporation, is  an indirect wholly-owned subsidiary  of
DWDC.  The Trustees who are not, and were not at the time they voted, interested
persons of  the Trusts,  as defined  in the  Act (the  "Independent  Trustees"),
approved,  at their  meeting held on  October 30,  1992, Distribution Agreements
appointing the Distributor as  exclusive distributor of  the Trusts' shares  and
providing  for the  Distributor to bear  distribution expenses not  borne by the
Trusts. At the same meeting,  the Trustees of the  Trusts, including all of  the
Independent Trustees,
 
                                      A-4
<PAGE>
   
approved  new Distribution Agreements between the Trusts and the Distributor, to
take effect upon  the spin-off  by Sears.  The new  Distribution Agreements  are
substantively  identical to the current  Distribution Agreements in all material
respects,  except  for  the  dates   of  effectiveness.  By  their  terms,   the
Distribution  Agreements had initial terms ending  April 30, 1994, and they will
remain in effect from year  to year thereafter if  approved by the Trustees.  At
their  meetings  held on  April 17,  1996,  the Trustees,  including all  of the
Independent Trustees,  voted  to approve  the  most recent  continuance  of  the
Distribution Agreements until April 30, 1997.
    
 
    As  discussed  in the  Appendix to  the Prospectuses,  the Trusts  have each
adopted a Plan  of Distribution (the  "Plan") pursuant to  Rule 12b-1 under  the
Act.  The adoptions of the Plans of  Money Trust, Tax-Free Trust, and Government
Securities Trust  were made  on  March 21,  1983.  These respective  Plans  were
initially  approved by the Trustees of the respective Trusts on January 18, 1983
and by the respective Trust's shareholders on March 17, 1983 and March 18, 1983.
The Plan of California Tax-Free Trust was  adopted by the Trustees of the  Trust
on  July 18, 1991 and by DWR, as sole shareholder, on October 4, 1991, whereupon
it went into  effect. On April  29, 1992, the  Trustees approved continuance  of
these  Plans until April 30, 1993. In  all instances, the vote of the respective
Trustees included a majority  of the Trustees  who are not and  were not at  the
time  of their  votes interested persons  of the Trust  and who have  and had no
direct or  indirect  financial  interest  in the  operation  of  the  Plan  (the
"Independent 12b-1 Trustees"), cast in person at meetings called for the purpose
of  voting  on such  Plans  and Agreements.  The  California Tax-Free  Trust has
undertaken, in  its  Registration  Statement,  to  seek  subsequent  shareholder
approval of the Plan at its first Annual or Special Meeting of Shareholders held
after  the effective date of the  Registration Statement of which this Statement
of Additional Information is a part.
 
    At their meetings  held on  October 30, 1992,  the Trustees  of the  Trusts,
including  all of the Independent 12b-1 Trustees, approved certain amendments to
the Plan which took  effect in January,  1993 and were  designed to reflect  the
fact  that  upon the  reorganization referred  to  above the  share distribution
activities theretofore performed for the Trusts  by Dean Witter were assumed  by
the  Distributor, and  Dean Witter's  sales activities  are now  being performed
pursuant to the terms of a selected dealer agreement between the Distributor and
Dean Witter. The amendments provide that  payments under the Plans will be  made
to the Distributor rather than to Dean Witter, as before the amendment, and that
the  Distributor in  turn is  authorized to  make payments  to Dean  Witter, its
affiliates or other selected broker-dealers (or direct that the Trusts pay  such
entities  directly). The Distributor  is also authorized to  retain part of such
payments as compensation for its own distribution-related expenses. This amended
Plan was approved  by the  shareholders of  California Tax-Free  Trust at  their
meeting held on January 13, 1993.
 
    Under  the respective Plans, the Distributor  has expanded the nature of its
promotional activities on  behalf of  the respective  Trusts and  used its  best
efforts to foster additional sales of Trust shares. The respective Plans provide
that  the  Distributor bears  the expense  of  all promotional  and distribution
related activities on behalf of the respective Trusts, except for expenses  that
the  respective  Trustees  determine  to  reimburse,  as  described  below.  The
following activities and services may be  provided by the Distributor under  the
respective  Plans: (1) compensation to  sales representatives of the Distributor
and  other  broker-dealers;   (2)  sales   incentives  and   bonuses  to   sales
representatives and to marketing personnel in connection with promoting sales of
shares;  (3) expenses incurred  in connection with promoting  sales of shares of
the Trust; (4) preparing  and distributing sales  literature; and (5)  providing
advertising  and promotional activities, including  direct mail solicitation and
television, radio, newspaper, magazine and other media advertisements.
 
    Dean Witter  account  executives are  paid  an annual  residual  commission,
currently a gross residual of up to 0.10% of the current value of the respective
accounts  for  which  they are  the  account  executives of  record.  The "gross
residual" is a charge which reflects residual commissions paid by Dean Witter to
its account executives and Dean Witter's expenses associated with the  servicing
of  shareholder's accounts,  including the  expenses of  operating Dean Witter's
branch offices in connection with the servicing of shareholder's accounts, which
expenses include lease costs, the  salaries and employee benefits of  operations
and  sales support personnel, utility costs,  communications costs and the costs
of stationery and supplies and other expenses relating to branch office  serving
of shareholder accounts.
 
                                      A-5
<PAGE>
    Each  Trust is authorized to reimburse the Distributor for specific expenses
the Distributor incurs or  plans to incur in  promoting the distribution of  the
respective  Trust's shares.  Reimbursement is  made through  monthly payments in
such amounts determined  in advance  of each  fiscal quarter  by the  respective
Trustees,  including a majority of the  Independent Trustees. The amount of each
monthly payment may  in no  event exceed  an amount equal  to a  payment at  the
annual  rate of  .15 of 1%  of the Trust's  average daily net  assets during the
month. No interest or  other financing charges will  be incurred by Dean  Witter
for  which  reimbursement  payments  under  the Plan  will  be  made.  In making
quarterly determinations of the amounts that may be expended by each Trust,  the
Distributor  provides, and the respective Trustees review, a quarterly budget of
projected incremental distribution  expenses to  be incurred on  behalf of  each
Trust,  together with a report explaining  the purposes and anticipated benefits
of incurring such expenses. The  respective Trustees determine which  particular
expenses,  and the  portions thereof, that  may be  borne by each  Trust, and in
making  such  determination  shall  consider  the  scope  of  the  Distributor's
commitment to promoting the distribution of the respective Trusts' shares.
 
   
    Money  Trust,  Tax-Free  Trust,  California  Tax-Free  Trust  and Government
Securities  Trust  accrued  $6,495,409,   $1,560,662,  $351,571  and   $570,309,
respectively, to the Distributor pursuant to the Plans for the fiscal year ended
June  30, 1996. Based upon the total amounts spent by the Distributor during the
period, it is estimated that the amounts  paid by the Trusts to the  Distributor
for  distribution were spent in approximately  the following ways: for the Money
Trust: (i) advertising  -- $-0-; (ii)  printing and mailing  of prospectuses  to
other  than current shareholders -- $-0-;  (iii) compensation to underwriters --
$-0-; (iv) compensation to dealers -- $-0-; (v) compensation to sales  personnel
- --   $-0-;  and  (vi)  other,  which   includes  to  Dean  Witter  for  expenses
substantially all  of  which  relate  to  compensation  of  sales  personnel  --
$6,495,409;  for the Tax-Free Trust: (i)  advertising -- $-0-; (ii) printing and
mailing of  prospectuses  to other  than  current shareholders  --  $-0-;  (iii)
compensation  to underwriters -- $-0-; (iv) compensation to dealers -- $-0-; (v)
compensation to sales personnel -- $-0-; and (vi) other, which includes to  Dean
Witter  for expenses substantially all of  which relate to compensation of sales
personnel -- $1,560,662; for the  California Tax-Free Trust: (i) advertising  --
$-0-;   (ii)  printing  and  mailing  of  prospectuses  to  other  than  current
shareholders  --  $-0-;  (iii)  compensation  to  underwriters  --  $-0-;   (iv)
compensation  to dealers --  $-0-; (v) compensation to  sales personnel -- $-0-;
and (vi) other, which includes to Dean Witter for expenses substantially all  of
which  relate to compensation of sales personnel -- $351,571; and for Government
Securities Trust:  (i)  advertising  --  $-0-;  (ii)  printing  and  mailing  of
prospectuses  to other than current shareholders  -- $-0-; (iii) compensation to
underwriters -- $-0-; (iv) compensation to dealers -- $-0-; (v) compensation  to
sales  personnel --  $-0-; and  (vi) other,  which includes  to Dean  Witter for
expenses substantially all of which relate to compensation of sales personnel --
$570,309.
    
 
    Under each Plan,  the Distributor  will use  its best  efforts in  rendering
services  to the respective  Trusts, but in the  absence of willful misfeasance,
bad faith,  gross  negligence or  reckless  disregard of  its  obligations,  the
Distributor  will not be liable to any of such Trusts or any of its shareholders
for any error of judgment or  mistake of law or for  any act of omission or  for
any losses sustained by any of such Trusts or their shareholders.
 
    The   respective  Plans  of  Money  Trust,  Tax-Free  Trust  and  Government
Securities Trust remained  in effect until  December 31, 1984,  and the Plan  of
California  Tax-Free Trust  remained in  effect until  April 30,  1992, and such
Plans will  remain  in  effect  from year  to  year  thereafter,  provided  such
continuances  are  approved annually  by  a vote  of  the Trustees,  including a
majority of the Independent 12b-1 Trustees. Any amendment to increase materially
the maximum amount authorized to  be spent under each  Plan must be approved  by
the shareholders of each Trust, and all material amendments to each Plan must be
approved  by  the Trustees  in  the manner  described  above. Each  Plan  may be
terminated at any time, without payment of any penalty, by vote of a majority of
the Independent 12b-1 Trustees or by a vote of the holders of a majority of  the
outstanding  voting securities of each Trust (as defined in the Act) on not more
than 30 days written  notice to any  other party to the  Plan. The authority  to
make  reimbursement payments to the  Distributor automatically terminates in the
event of an assignment (as defined in the Act); however, the Trustees' authority
under each Plan  to utilize its  proceeds to finance  the distribution of  Trust
shares  would continue. After such an  assignment, the Trusts' authority to make
payments to their
 
                                      A-6
<PAGE>
Distributor would resume, subject  to certain conditions. So  long as the  Plans
are  in  effect, the  selection  or nomination  of  the Independent  Trustees is
committed to the discretion of the Independent 12b-1 Trustees.
 
    Under each Plan, the Distributor  provides the respective Trust, for  review
by  its Trustees, and the Trustees review, promptly after the end of each fiscal
quarter, a  written  report  regarding  the  incremental  distribution  expenses
incurred  by the Distributor on behalf of each Trust during such fiscal quarter,
which report  includes (1)  an itemization  of  the types  of expenses  and  the
purposes  therefor; (2) the amounts  of such expenses; and  (3) a description of
the benefits derived  by each Trust.  In the Trustees'  quarterly review of  the
Plans   they  consider  their   continued  appropriateness  and   the  level  of
compensation provided therein.
 
   
    Pursuant to the Plans of all Trusts, the Distributor provided the  Trustees,
at  their Meetings held on April 17, 1996, with all the information the Trustees
deemed necessary to make an informed  determination on whether each Plan  should
be  continued. In making their determination to continue each of the Plans until
April 30, 1997, the Trustees, including  all of the Independent 12b-1  Trustees,
arrived  at the conclusion that the Plans had benefited each of the Trusts. This
conclusion was based upon  the Distributor's belief  that the expenditures  made
pursuant  to the Plans had tended to arrest the decline of the Trusts' assets by
meeting the competitive efforts  of other, similar  financial products, and  had
encouraged  the account  executives employed  by Dean  Witter to  increase their
efforts in selling shares of the Trusts. The Trustees, including the Independent
12b-1 Trustees, also concluded  that, in their judgment,  there is a  reasonable
likelihood  that the Plans will continue to benefit each of the Trusts and their
shareholders.
    
 
    No interested person of the Trusts nor any Trustee of the Trusts who is  not
an  interested person of  the Trusts, as defined  in the Act,  had any direct or
indirect financial interest in the operation  of the Plans except to the  extent
that  the Distributor or certain of its employees  may be deemed to have such an
interest as a result  of benefits derived from  the successful operation of  the
Plans  or as a result of receiving  a portion of the amounts expended thereunder
by the Trusts.
 
TRUSTEES AND OFFICERS
- --------------------------------------------------------------------------------
 
   
    The Trustees and Executive Officers of the Trusts, their principal  business
occupations  during the  last five  years and  their affiliations,  if any, with
InterCapital, the 81 Dean Witter Funds and the 13 TCW/DW Funds, are shown below.
    
 
   
<TABLE>
<CAPTION>
   NAME, AGE, POSITION WITH
      TRUSTS AND ADDRESS              PRINCIPAL OCCUPATIONS DURING LAST FIVE YEARS
- ------------------------------       ----------------------------------------------
<S>                                  <C>
Michael Bozic (55) ...........       Chairman and Chief Executive Officer of Levitz
Trustee                              Furniture Corporation (since November,  1995);
c/o Levitz Furniture                 Director  or Trustee of the Dean Witter Funds;
Corporation                          formerly President and Chief Executive Officer
6111 Broken Sound Parkway            of Hills  Department Stores  (May,  1991-July,
Boca Raton, Florida                  1995);  formerly  variously,  Chairman,  Chief
                                     Executive   Officer,   President   and   Chief
                                     Operating  Officer  (1987-1991)  of  the Sears
                                     Merchandise Group of  Sears, Roebuck and  Co.;
                                     Director   of  Eaglemark  Financial  Services,
                                     Inc.,  the  United  Negro  College  Fund   and
                                     Wierton Steel Corporation.
</TABLE>
    
 
                                      A-7
<PAGE>
   
<TABLE>
<CAPTION>
   NAME, AGE, POSITION WITH
      TRUSTS AND ADDRESS              PRINCIPAL OCCUPATIONS DURING LAST FIVE YEARS
- ------------------------------       ----------------------------------------------
<S>                                  <C>
Charles A. Fiumefreddo*              Chairman, Chief Executive Officer and Director
(63) .........................       of   InterCapital,   Distributors   and  DWSC;
Chairman, Trustee,                   Executive Vice President and Director of  Dean
President and Chief                  Witter;   Chairman,   Trustee   or   Director,
Executive Officer                    President and Chief  Executive Officer of  the
Two World Trade Center               Dean  Witter Funds;  Chairman, Chief Executive
New York, New York                   Officer  and  Trustee  of  the  TCW/DW  Funds;
                                     formerly Executive Vice President and Director
                                     of  DWDC; Chairman and Director of Dean Witter
                                     Trust Company  ("DWTC"); Director  of  various
                                     DWDC  subsidiaries  and  affiliates;  formerly
                                     Executive Vice President and Director of  DWDC
                                     (until February, 1993).
Edwin J. Garn (63) ...........       Director  or Trustee of the Dean Witter Funds;
Trustee                              formerly  United   States   Senator   (R-Utah)
c/o Huntsman Chemical                (1974-1992)   and  Chairman,   Senate  Banking
Corporation                          Committee (1980-1986); formerly Mayor of  Salt
500 Huntsman Way                     Lake    City,   Utah   (1971-1974);   formerly
Salt Lake City, Utah                 Astronaut,  Space  Shuttle  Discovery   (April
                                     12-19, 1985); Vice Chairman, Huntsman Chemical
                                     Corporation (since January, 1993); Director of
                                     Franklin  Quest (time  management systems) and
                                     John Alden  Financial  Corp.;  Member  of  the
                                     board   of   various   civic   and  charitable
                                     organizations.
John R. Haire (71) ...........       Chairman of the  Audit Committee and  Chairman
Trustee                              of  the Committee of  Independent Directors or
Two World Trade Center               Trustees and Director or  Trustee of the  Dean
New York, New York                   Witter  Funds; Chairman of the Audit Committee
                                     and  Chairman   of   the  Committee   of   the
                                     Independent Trustees and Trustee of the TCW/DW
                                     Funds;  formerly President, Council for Aid to
                                     Education (1978-1989) and  Chairman and  Chief
                                     Executive  Officer  of Anchor  Corporation, an
                                     Investment Adviser  (1964-1978);  Director  of
                                     Washington National Corporation (insurance).
Dr. Manuel H. Johnson (47) ...       Senior  Partner, Johnson  Smick International,
Trustee                              Inc., a  consulting  firm; Koch  Professor  of
c/o Johnson Smick                    International  Economics  and Director  of the
International, Inc.                  Center for  Global  Market Studies  at  George
1133 Connecticut Avenue N.W.         Mason   University  (since  September,  1990);
Washington, D.C.                     Co-Chairman and  a  founder of  the  Group  of
                                     Seven Council (G7C), an international economic
                                     commission  (since September,  1990); Director
                                     or Trustee of the  Dean Witter Funds;  Trustee
                                     of the TCW/DW Funds; Director of NASDAQ (since
                                     June,  1995);  Director  of  Greenwich Capital
                                     Markets Inc.  (broker-dealer);  formerly  Vice
                                     Chairman  of  the  Board of  Governors  at the
                                     Federal Reserve System (February,  1986-August
                                     1990)  and  Assistant  Secretary  of  the U.S.
                                     Treasury (1982-1986).
</TABLE>
    
 
                                      A-8
<PAGE>
   
<TABLE>
<CAPTION>
   NAME, AGE, POSITION WITH
      TRUSTS AND ADDRESS              PRINCIPAL OCCUPATIONS DURING LAST FIVE YEARS
- ------------------------------       ----------------------------------------------
<S>                                  <C>
Michael E. Nugent (60) .......       General  Partner,  Triumph  Capital,  L.P.,  a
Trustee                              private  investment  partnership;  Director or
c/o Triumph Capital, L.P.            Trustee of the Dean  Witter Funds; Trustee  of
237 Park Avenue                      the  TCW/DW  Funds;  formerly  Vice President,
New York, New York                   Bankers   Trust   Company   and   BT   Capital
                                     Corporation  (1984-1988); Director  of various
                                     business organizations.
Philip J. Purcell* (52) ......       Chairman of the Board  of Directors and  Chief
Trustee                              Executive  Officer  of DWDC,  Dean  Witter and
Two World Trade Center               Novus  Credit  Services   Inc.;  Director   of
New York, New York                   InterCapital,  DWSC and Distributors; Director
                                     or Trustee of the Dean Witter Funds;  Director
                                     and/or officer of various DWDC subsidiaries.
John L. Schroeder (66) .......       Retired;  Director  or  Trustee  of  the  Dean
Trustee                              Witter Funds;  Trustee  of the  TCW/DW  Funds;
c/o Gordon Altman Butowsky           Director   of   Citizens   Utilities  Company;
 Weitzen Shalov & Wein               formerly Executive  Vice President  and  Chief
Counsel to the Independent           Investment   Officer  of  the  Home  Insurance
Trustees                             Company   (August,   1991-September,    1995);
114 West 47th Street                 formerly Chairman and Chief Investment Officer
New York, New York                   of   Axe-Houghton  Management   and  the  Axe-
                                     Houghton Funds  (April, 1983-June,  1991)  and
                                     President  of  USF&G Financial  Services, Inc.
                                     (June, 1990-June, 1991).
Sheldon Curtis (64) ..........       Senior Vice President,  Secretary and  General
Vice President, Secretary            Counsel  of InterCapital and DWSC; Senior Vice
 and General Counsel                 President and Secretary  of Dean Witter  Trust
Two World Trade Center               Company  (since  October,  1989);  Senior Vice
New York, New York                   President, Assistant  Secretary and  Assistant
                                     General  Counsel  of Dean  Witter Distributors
                                     Inc.;  Assistant   Secretary  of   DWR;   Vice
                                     President,  Secretary  and General  Counsel of
                                     the Dean Witter Funds and the TCW/DW Funds.
Patricia A. Cuddy (42) .......       Vice President  of InterCapital  (since  June,
Vice President                       1994);  Vice President of  various Dean Witter
Two World Trade Center               Funds;  formerly  Senior  Vice  President   of
New York, New York                   various   investment   companies   managed  by
                                     Dreyfus Corporation.
Jonathan R. Page (49) ........       Senior Vice  President of  InterCapital;  Vice
Vice President                       President of various Dean Witter Funds.
Two World Trade Center
New York, New York
Katherine H. Stromberg               Vice President of InterCapital (since October,
(48) .........................       1991).    Previously   Vice    President   and
Vice President                       Investment Officer  of  Kidder  Peabody  Asset
Two World Trade Center               Management.
New York, New York
Thomas F. Caloia (50) ........       First  Vice President  and Assistant Treasurer
Treasurer                            of InterCapital  and  DWSC; Treasurer  of  the
Two World Trade Center               Dean Witter Funds and the TCW/DW Funds.
New York, New York
</TABLE>
    
 
- ------------------------
 *Denotes Trustees who are "Interested persons" of the Trusts, as defined in the
  Act.
 
                                      A-9
<PAGE>
   
    In  addition, Robert  M. Scanlan, President  and Chief  Operating Officer of
InterCapital and DWSC,  Executive Vice  President of DWTC  and Distributors  and
Director  of  DWTC,  Joseph J.  McAlinden,  Executive Vice  President  and Chief
Investment Officer of InterCapital, and  Director of DWTC, Robert S.  Giambrone,
Senior  Vice President of InterCapital, DWSC, Distributors and DWTC and Director
of DWTC and James  F. Willison, Senior Vice  President of InterCapital are  Vice
Presidents of the Fund. Barry Fink and Marilyn K. Cranney, First Vice Presidents
and  Assistant General Counsels of InterCapital and DWSC and Lou Anne D. McInnis
and Ruth Rossi, Vice Presidents  and Assistant General Counsels of  InterCapital
and  DWSC and  Carsten Otto, a  Staff Attorney with  InterCapital, are Assistant
Secretaries of the Trusts.
    
 
   
THE BOARD OF TRUSTEES, THE INDEPENDENT TRUSTEES, AND THE COMMITTEES
    
 
   
    The Board of Trustees consists of eight (8) trustees. These same individuals
also serve as directors or  trustees for all of the  Dean Witter Funds, and  are
referred  to in this  section as Trustees. As  of the date  of this Statement of
Additional Information, there are a total of 81 Dean Witter Funds, comprised  of
121  portfolios. As of June 30, 1996, the Dean Witter Funds had total net assets
of approximately $76.3 billion and more than five million shareholders.
    
 
   
    Six Trustees  (75% of  the total  number) have  no affiliation  or  business
connection with InterCapital or any of its affiliated persons and do not own any
stock  or other securities issued by  InterCapital's parent company, DWDC. These
are the "disinterested" or "independent"  Trustees. The other two Trustees  (the
"management  Trustees")  are  affiliated  with  InterCapital.  Four  of  the six
independent Trustees are also Independent Trustees of the TCW/DW Funds.
    
 
   
    Law and regulation establish both general guidelines and specific duties for
the Independent Trustees.  The Dean  Witter Funds seek  as Independent  Trustees
individuals  of distinction and  experience in business  and finance, government
service or academia; these are people whose advice and counsel are in demand  by
others  and for  whom there is  often competition.  To accept a  position on the
Funds' Boards, such individuals may reject other attractive assignments  because
the  Funds make  substantial demands  on their time.  Indeed, by  serving on the
Funds' Boards, certain Trustees who would  otherwise be qualified and in  demand
to serve on bank boards would be prohibited by law from doing so.
    
 
   
    All  of the Independent Trustees serve as members of the Audit Committee and
the Committee of the Independent Trustees.  Three of them also serve as  members
of  the Derivatives Committee. During the calendar year ended December 31, 1995,
the three Committees held a combined  total of fifteen meetings. The  Committees
hold  some  meetings at  InterCapital's offices  and some  outside InterCapital.
Management Trustees or  officers do not  attend these meetings  unless they  are
invited for purposes of furnishing information or making a report.
    
 
   
    The  Committee of the  Independent Trustees is  charged with recommending to
the full Board  approval of management,  advisory and administration  contracts,
Rule  12b-1  plans  and distribution  and  underwriting  agreements; continually
reviewing Fund performance;  checking on  the pricing  of portfolio  securities,
brokerage  commissions, transfer agent costs  and performance, and trading among
Funds in the  same complex; and  approving fidelity bond  and related  insurance
coverage and allocations, as well as other matters that arise from time to time.
The Independent Trustees are required to select and nominate individuals to fill
any  Independent Trustee vacancy on the Board of  any Fund that has a Rule 12b-1
plan of distribution. Most of the Dean Witter Funds have such a plan.
    
 
   
    The Audit  Committee is  charged with  recommending to  the full  Board  the
engagement  or  discharge  of  the  Fund's  independent  accountants;  directing
investigations into matters  within the  scope of  the independent  accountants'
duties,  including the power  to retain outside  specialists; reviewing with the
independent accountants the audit plan  and results of the auditing  engagement;
approving  professional  services provided  by  the independent  accountants and
other accounting firms prior to the performance of such services; reviewing  the
independence  of the independent accountants; considering the range of audit and
non-audit fees;  reviewing  the  adequacy  of  the  Fund's  system  of  internal
controls;  and preparing  and submitting Committee  meeting minutes  to the full
Board.
    
 
                                      A-10
<PAGE>
   
    Finally, the  Board of  each  Fund has  formed  a Derivatives  Committee  to
establish  parameters for and oversee the activities of the Fund with respect to
derivative investments, if any, made by the Fund.
    
 
   
DUTIES OF CHAIRMAN OF COMMITTEE OF THE INDEPENDENT TRUSTEES AND AUDIT COMMITTEE
    
 
   
    The Chairman of  the Committee  of the  Independent Trustees  and the  Audit
Committee  maintains an  office at  the Funds' headquarters  in New  York. He is
responsible for keeping abreast of regulatory and industry developments and  the
Funds'  operations and management. He  screens and/or prepares written materials
and identifies  critical  issues  for  the  Independent  Trustees  to  consider,
develops  agendas  for Committee  meetings, determines  the  type and  amount of
information that the Committees will need to form a judgment on various  issues,
and  arranges to have  that information furnished to  Committee members. He also
arranges for  the services  of independent  experts and  consults with  them  in
advance  of meetings  to help  refine reports and  to focus  on critical issues.
Members of the Committees believe that the person who serves as Chairman of both
Committees and guides their efforts is  pivotal to the effective functioning  of
the Committees.
    
 
   
    The  Chairman of the  Committees also maintains  continuous contact with the
Funds' management, with independent counsel to the Independent Trustees and with
the Funds' independent auditors.  He arranges for a  series of special  meetings
involving  the  annual  review  of  investment  advisory,  management  and other
operating contracts of  the Funds  and, on  behalf of  the Committees,  conducts
negotiations with the Investment Manager and other service providers. In effect,
the  Chairman of the Committees  serves as a combination  of chief executive and
support staff of the Independent Trustees.
    
 
   
    The Chairman of  the Committee  of the  Independent Trustees  and the  Audit
Committee  is  not  employed by  any  other  organization and  devotes  his time
primarily to  the services  he performs  as Committee  Chairman and  Independent
Trustee  of the Dean Witter Funds and  as an Independent Trustee and, since July
1, 1996, as Chairman of the Committee of the Independent Trustees and the  Audit
Committee  of the TCW/DW Funds. The current Committee Chairman has had more than
35 years experience as a senior executive in the investment company industry.
    
 
   
ADVANTAGES OF HAVING SAME INDIVIDUALS AS INDEPENDENT TRUSTEES FOR ALL DEAN
WITTER FUNDS
    
 
   
    The Independent Trustees and the  Funds' management believe that having  the
same  Independent  Trustees  for  each  of  the  Dean  Witter  Funds  avoids the
duplication  of  effort  that  would  arise  from  having  different  groups  of
individuals  serving as Independent  Trustees for each  of the Funds  or even of
sub-groups of Funds.  They believe  that having  the same  individuals serve  as
Independent  Trustees of  all the  Funds tends  to increase  their knowledge and
expertise regarding matters which affect the Fund complex generally and enhances
their ability  to negotiate  on behalf  of  each Fund  with the  Fund's  service
providers. This arrangement also precludes the possibility of separate groups of
Independent  Trustees arriving at conflicting decisions regarding operations and
management of the  Funds and  avoids the cost  and confusion  that would  likely
ensue.  Finally, having the  same Independent Trustees serve  on all Fund Boards
enhances the ability of  each Fund to  obtain, at modest  cost to each  separate
Fund,  the services of Independent Trustees, and a Chairman of their Committees,
of the caliber, experience and business  acumen of the individuals who serve  as
Independent Trustees of the Dean Witter Funds.
    
 
COMPENSATION OF INDEPENDENT TRUSTEES
 
   
    The  Trusts pay each Independent Trustee an  annual fee of $1,000 plus a per
meeting fee of $50 for  meetings of the Board of  Trustees or committees of  the
Board  of Trustees attended by  the Trustee (the Trusts  pay the Chairman of the
Audit Committee an annual fee of $750  and pay the Chairman of the Committee  of
the  Independent Trustees an  additional annual fee of  $1,200). The Trusts also
reimburse such Trustees for travel and other out-of-pocket expenses incurred  by
them  in connection with  attending such meetings. Trustees  and officers of the
Trusts who are or have been employed by the Investment Manager or an  affiliated
company receive no compensation or expense reimbursement from the Trusts.
    
 
   
    The  following  tables  illustrate  the  compensation  paid  to  the Trusts'
Independent Trustees by the Trusts for the fiscal year ended June 30, 1996.
    
 
                                      A-11
<PAGE>
   
                               TRUST COMPENSATION
    
 
   
                           ACTIVE ASSETS MONEY TRUST
    
 
   
<TABLE>
<CAPTION>
                                                                   AGGREGATE
                                                                 COMPENSATION
NAME OF INDEPENDENT TRUSTEE                                      FROM THE FUND
- --------------------------------------------------------------  ---------------
<S>                                                             <C>
Michael Bozic.................................................      $1,700
Edwin J. Garn.................................................       1,750
John R. Haire.................................................       3,863(1)
Dr. Manuel H. Johnson.........................................       1,700
Michael E. Nugent.............................................       1,750
John L. Schroeder.............................................       1,750
</TABLE>
    
 
   
                          ACTIVE ASSETS TAX-FREE TRUST
    
 
   
<TABLE>
<CAPTION>
                                                                   AGGREGATE
                                                                 COMPENSATION
NAME OF INDEPENDENT TRUSTEE                                      FROM THE FUND
- --------------------------------------------------------------  ---------------
<S>                                                             <C>
Michael Bozic.................................................      $1,700
Edwin J. Garn.................................................       1,750
John R. Haire.................................................       3,863(1)
Dr. Manuel H. Johnson.........................................       1,700
Michael E. Nugent.............................................       1,750
John L. Schroeder.............................................       1,750
</TABLE>
    
 
   
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
    
 
   
<TABLE>
<CAPTION>
                                                                   AGGREGATE
                                                                 COMPENSATION
NAME OF INDEPENDENT TRUSTEE                                      FROM THE FUND
- --------------------------------------------------------------  ---------------
<S>                                                             <C>
Michael Bozic.................................................      $1,700
Edwin J. Garn.................................................       1,750
John R. Haire.................................................       3,863(1)
Dr. Manuel H. Johnson.........................................       1,700
Michael E. Nugent.............................................       1,750
John L. Schroeder.............................................       1,750
</TABLE>
    
 
   
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
    
 
   
<TABLE>
<CAPTION>
                                                                   AGGREGATE
                                                                 COMPENSATION
NAME OF INDEPENDENT TRUSTEE                                      FROM THE FUND
- --------------------------------------------------------------  ---------------
<S>                                                             <C>
Michael Bozic.................................................      $1,700
Edwin J. Garn.................................................       1,750
John R. Haire.................................................       3,863(1)
Dr. Manuel H. Johnson.........................................       1,700
Michael E. Nugent.............................................       1,750
John L. Schroeder.............................................       1,750
</TABLE>
    
 
- ------------------------
   
(1) Of Mr. Haire's compensation from each of the Trusts, $3,150 was paid to  him
    as  Chairman of  the Committee of  the Independent Trustees  ($2,400) and as
    Chairman of the Audit Committee ($750).
    
 
   
    The following  table  illustrates  the  compensation  paid  to  the  Trusts'
Independent  Trustees for the calendar year ended December 31, 1995 for services
to the 79 Dean Witter Funds and,  in the case of Messrs. Haire, Johnson,  Nugent
and  Schroeder, the 11 TCW/DW Funds that were in operation at December 31, 1995.
With respect to Messrs. Haire, Johnson,  Nugent and Schroeder, the TCW/DW  Funds
are  included solely because of a limited exchange privilege between those Funds
and five Dean Witter Money Market Funds. Mr. Schroeder was elected as a  Trustee
of the TCW/DW Funds on April 20, 1995.
    
 
                                      A-12
<PAGE>
   
              COMPENSATION FROM DEAN WITTER FUNDS AND TCW/DW FUNDS
    
 
   
<TABLE>
<CAPTION>
                                                                                        TOTAL
                                                                   FOR SERVICE AS   COMPENSATION
                               FOR SERVICE                          CHAIRMAN OF         PAID
                              AS DIRECTOR OR                       COMMITTEES OF    FOR SERVICES
                               TRUSTEE AND       FOR SERVICE AS     INDEPENDENT          TO
                             COMMITTEE MEMBER     TRUSTEE AND        DIRECTORS/        79 DEAN
                                OF 79 DEAN      COMMITTEE MEMBER    TRUSTEES AND       WITTER
                                  WITTER          OF 11 TCW/DW         AUDIT        FUNDS AND 11
NAME OF INDEPENDENT TRUSTEE       FUNDS              FUNDS           COMMITTEES     TCW/DW FUNDS
- ---------------------------  ----------------   ----------------   --------------   -------------
<S>                          <C>                <C>                <C>              <C>
Michael Bozic..............      $126,050           --                 --             $126,050
Edwin J. Garn..............       136,450           --                 --              136,450
John R. Haire..............        98,450           $82,038           $217,350(2)      397,838
Dr. Manuel H. Johnson......       136,450            82,038            --              218,488
Michael E. Nugent..........       124,200            75,038            --              199,238
John L. Schroeder..........       136,450            46,964            --              183,414
</TABLE>
    
 
- ------------------------
   
(2)  For the 79  Dean Witter Funds in  operation at December  31, 1995. As noted
    above, on July 1, 1996,  Mr. Haire became Chairman  of the Committee of  the
    Independent Trustees and the Audit Committee of the TCW/DW Funds in addition
    to continuing to serve in such positions for the Dean Witter Funds.
    
 
   
    As  of the date of this Statement  of Additional Information, 57 of the Dean
Witter Funds,  including the  Trusts, have  adopted a  retirement program  under
which  an Independent Trustee who retires after  serving for at least five years
(or such lesser  period as may  be determined  by the Board)  as an  Independent
Director  or Trustee  of any  Dean Witter Fund  that has  adopted the retirement
program (each such Fund referred to as an "Adopting Fund" and each such  Trustee
referred  to as an  "Eligible Trustee") is entitled  to retirement payments upon
reaching the eligible retirement age (normally, after attaining age 72).  Annual
payments  are based  upon length  of service.  Currently, upon  retirement, each
Eligible Trustee is entitled to receive from the Adopting Fund, commencing as of
his or her retirement date and continuing for the remainder of his or her  life,
an  annual retirement benefit (the  "Regular Benefit") equal to  25.0% of his or
her Eligible Compensation plus 0.4166666% of such Eligible Compensation for each
full month of service as an Independent Director or Trustee of any Adopting Fund
in excess of five years up to a maximum of 50.0% after ten years of service. The
foregoing percentages may be changed by the Board.(3) "Eligible Compensation" is
one-fifth of the total compensation earned by such Eligible Trustee for  service
to  the Adopting Fund in the five year  period prior to the date of the Eligible
Trustee's retirement. Benefits under the  retirement program are not secured  or
funded by the Adopting Funds.
    
 
   
    The  following  tables illustrate  the  retirement benefits  accrued  to the
Trusts' Independent Trustees by  the Trusts for the  fiscal year ended June  30,
1996  and by the 57 Dean Witter Funds  (including the Trusts) as of December 31,
1995, and the estimated retirement benefits for the Trusts' Independent Trustees
from the Trusts as  of June 30,  1996 and from  the 57 Dean  Witter Funds as  of
December 31, 1995.
    
 
   
         RETIREMENT BENEFITS FROM THE TRUSTS AND ALL DEAN WITTER FUNDS
    
 
   
                           ACTIVE ASSETS MONEY TRUST
    
 
   
<TABLE>
<CAPTION>
                                           FOR ALL ADOPTING FUNDS                                     ESTIMATED ANNUAL
                                   --------------------------------------   RETIREMENT BENEFITS           BENEFITS
                                        ESTIMATED                           ACCRUED AS EXPENSES      UPON RETIREMENT(4)
                                     CREDITED YEARS         ESTIMATED      ----------------------  ----------------------
                                      OF SERVICE AT       PERCENTAGE OF                 BY ALL       FROM      FROM ALL
                                       RETIREMENT           ELIGIBLE        BY THE     ADOPTING       THE      ADOPTING
NAME OF INDEPENDENT TRUSTEE           (MAXIMUM 10)        COMPENSATION       TRUST       FUNDS       TRUST       FUNDS
- ---------------------------------  -------------------  -----------------  ---------  -----------  ---------  -----------
<S>                                <C>                  <C>                <C>        <C>          <C>        <C>
Michael Bozic....................              10               50.0%      $     396  $    26,359  $     850  $    51,550
Edwin J. Garn....................              10               50.0             586       41,901        850       51,550
John R. Haire....................              10               50.0           1,685      261,763      2,315      130,404
Dr. Manuel H. Johnson............              10               50.0             242       16,748        850       51,550
Michael E. Nugent................              10               50.0             418       30,370        850       51,550
John L. Schroeder................               8               41.7             769       51,812        708       42,958
</TABLE>
    
 
                                      A-13
<PAGE>
   
                          ACTIVE ASSETS TAX-FREE TRUST
    
 
   
<TABLE>
<CAPTION>
                                           FOR ALL ADOPTING FUNDS                                     ESTIMATED ANNUAL
                                   --------------------------------------   RETIREMENT BENEFITS           BENEFITS
                                        ESTIMATED                           ACCRUED AS EXPENSES      UPON RETIREMENT(4)
                                     CREDITED YEARS         ESTIMATED      ----------------------  ----------------------
                                      OF SERVICE AT       PERCENTAGE OF                 BY ALL       FROM      FROM ALL
                                       RETIREMENT           ELIGIBLE        BY THE     ADOPTING       THE      ADOPTING
NAME OF INDEPENDENT TRUSTEE           (MAXIMUM 10)        COMPENSATION       TRUST       FUNDS       TRUST       FUNDS
- ---------------------------------  -------------------  -----------------  ---------  -----------  ---------  -----------
<S>                                <C>                  <C>                <C>        <C>          <C>        <C>
Michael Bozic....................              10               50.0%      $     396  $    26,359  $     850  $    51,550
Edwin J. Garn....................              10               50.0             586       41,901        850       51,550
John R. Haire....................              10               50.0           1,685      261,763      2,315      130,404
Dr. Manuel H. Johnson............              10               50.0             242       16,748        850       51,550
Michael E. Nugent................              10               50.0             418       30,370        850       51,550
John L. Schroeder................               8               41.7             769       51,812        708       42,958
</TABLE>
    
 
   
                    ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST
    
 
   
<TABLE>
<CAPTION>
                                           FOR ALL ADOPTING FUNDS                                     ESTIMATED ANNUAL
                                   --------------------------------------   RETIREMENT BENEFITS           BENEFITS
                                        ESTIMATED                           ACCRUED AS EXPENSES      UPON RETIREMENT(4)
                                     CREDITED YEARS         ESTIMATED      ----------------------  ----------------------
                                      OF SERVICE AT       PERCENTAGE OF                 BY ALL       FROM      FROM ALL
                                       RETIREMENT           ELIGIBLE        BY THE     ADOPTING       THE      ADOPTING
NAME OF INDEPENDENT TRUSTEE           (MAXIMUM 10)        COMPENSATION       TRUST       FUNDS       TRUST       FUNDS
- ---------------------------------  -------------------  -----------------  ---------  -----------  ---------  -----------
<S>                                <C>                  <C>                <C>        <C>          <C>        <C>
Michael Bozic....................              10               50.0%      $     396  $    26,359  $     850  $    51,550
Edwin J. Garn....................              10               50.0             670       41,901        850       51,550
John R. Haire....................              10               50.0           5,233      261,763      2,203      130,404
Dr. Manuel H. Johnson............              10               50.0             267       16,748        850       51,550
Michael E. Nugent................              10               50.0             503       30,370        850       51,550
John L. Schroeder................               8               41.7             769       51,812        708       42,958
</TABLE>
    
 
   
                   ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
    
 
   
<TABLE>
<CAPTION>
                                           FOR ALL ADOPTING FUNDS                                     ESTIMATED ANNUAL
                                   --------------------------------------   RETIREMENT BENEFITS           BENEFITS
                                        ESTIMATED                           ACCRUED AS EXPENSES      UPON RETIREMENT(4)
                                     CREDITED YEARS         ESTIMATED      ----------------------  ----------------------
                                      OF SERVICE AT       PERCENTAGE OF                 BY ALL       FROM      FROM ALL
                                       RETIREMENT           ELIGIBLE        BY THE     ADOPTING       THE      ADOPTING
NAME OF INDEPENDENT TRUSTEE           (MAXIMUM 10)        COMPENSATION       TRUST       FUNDS       TRUST       FUNDS
- ---------------------------------  -------------------  -----------------  ---------  -----------  ---------  -----------
<S>                                <C>                  <C>                <C>        <C>          <C>        <C>
Michael Bozic....................              10               50.0%      $     396  $    26,359  $     850  $    51,550
Edwin J. Garn....................              10               50.0             586       41,901        850       51,550
John R. Haire....................              10               50.0           1,685      261,763      2,315      130,404
Dr. Manuel H. Johnson............              10               50.0             242       16,748        850       51,550
Michael E. Nugent................              10               50.0             418       30,370        850       51,550
John L. Schroeder................               8               41.7             769       51,812        708       42,958
</TABLE>
    
 
- ------------------------
   
(3)  An Eligible Trustee may  elect alternate payments of  his or her retirement
    benefits based upon the  combined life expectancy  of such Eligible  Trustee
    and his or her spouse on the date of such Eligible Trustee's retirement. The
    amount  estimated to be payable under  this method, through the remainder of
    the later of  the lives of  such Eligible  Trustee and spouse,  will be  the
    actuarial  equivalent  of the  Regular  Benefit. In  addition,  the Eligible
    Trustee may elect that the  surviving spouse's periodic payment of  benefits
    will  be equal  to either 50%  or 100%  of the previous  periodic amount, an
    election that, respectively,  increases or decreases  the previous  periodic
    amount  so that the  resulting payments will be  the actuarial equivalent of
    the Regular Benefit.
    
 
   
(4) Based on  current levels  of compensation.  Amount of  annual benefits  also
    varies depending on the Trustee's elections described in Footnote (3) above.
    
 
                                      A-14
<PAGE>
   
    As  of the date  of this Statement of  Additional Information, the aggregate
number of  shares of  beneficial interest  of each  Trust owned  by the  Trusts'
officers  and Trustees as a group was less than 1 percent of each Trust's shares
of beneficial interest outstanding.
    
 
PORTFOLIO TRANSACTIONS AND BROKERAGE
- --------------------------------------------------------------------------------
 
   
    The Investment  Manager  is  responsible  for  decisions  to  buy  and  sell
securities  for the Trusts and arranges  for the execution of portfolio security
transactions on behalf of the Trusts. Purchases of portfolio securities are made
from dealers, underwriters and  issuers; sales, if any,  prior to maturity,  are
made  to dealers  and issuers.  The Trusts do  not normally  incur any brokerage
commission expense on such transactions. Money market instruments are  generally
traded  on a "net" basis with dealers acting as principal for their own accounts
without a stated commission, although the price of the security usually includes
a profit to the dealer. Securities purchased in underwritten offerings include a
fixed amount of compensation  to the underwriter, generally  referred to as  the
underwriter's  concession  or discount.  When securities  are purchased  or sold
directly from  or  to  an issuer,  no  commissions  or discounts  are  paid.  No
brokerage  commissions were paid on any  transactions entered into by the Trusts
during the fiscal year ended June 30, 1996.
    
 
    The policy of  the Trusts regarding  purchases and sales  of securities  for
their  respective  portfolios is  that primary  consideration  will be  given to
obtaining the most favorable price and efficient execution of transactions  with
those  dealers who  the Investment Manager  believes provide  the most favorable
prices and  are capable  of providing  efficient executions.  If the  Investment
Manager  believes such price  and execution can  be obtained from  more than one
dealer, it may give consideration  to placing portfolio transactions with  those
dealers  who  also furnish  research and  other  services to  the Trusts  or the
Investment Manager. Such services may include but are not limited to, any one or
more of the  following: information  as to  the availability  of securities  for
purchases  or sale; statistical or factual information or opinions pertaining to
investments;  wire  services;  and   appraisals  or  evaluations  of   portfolio
securities.
 
    The information and services received by the Investment Manager from dealers
may  be of benefit  to the Investment  Manager in the  management of accounts of
some or all of  its other clients and  may not in all  cases benefit the  Trusts
directly.  While the  receipt of  such information  and services  are useful and
important in  supplementing  its own  research  and facilities,  the  Investment
Manager  believes the value  of such services  is not determinable  and does not
significantly reduce its expenses. The Trusts  do not reduce the management  fee
they pay to the Investment Manager by any amount that may be attributable to the
value of such services.
 
    Pursuant  to an order of the  Securities and Exchange Commission, the Trusts
may effect principal transactions in certain money market instruments with  Dean
Witter.  The  Trusts will  limit  their transactions  with  Dean Witter  to U.S.
Government and  Government  Agency  Securities, Bank  Money  Instruments  (I.E.,
Certificates  of  Deposit and  Banker's Acceptances)  and Commercial  Paper (not
including Tax-Exempt Municipal Paper). Such  transactions will be effected  with
Dean  Witter only when the price available  from Dean Witter is better than that
available from other dealers.
 
    While the  Trusts do  not  anticipate that  they  will incur  any  brokerage
commissions,  consistent with the policy described above, brokerage transactions
in securities listed on exchanges or admitted to unlisted trading privileges may
be effected through Dean  Witter. In order for  Dean Witter to effect  portfolio
transactions  for any of the Trusts, the commissions, fees or other remuneration
received by Dean Witter must be reasonable and fair compared to the commissions,
fees or other remuneration paid to  other brokers in connection with  comparable
transactions involving similar securities being purchased or sold on an exchange
during  a comparable period  of time. This  standard would allow  Dean Witter to
receive no more than the remuneration which would be expected to be received  by
an  unaffiliated broker in a commensurate arm's-length transaction. Furthermore,
the Trustees of  the Trust, including  a majority  of the Trustees  who are  not
"interested"  Trustees, have adopted procedures which are reasonably designed to
provide that any commissions, fees or other remuneration paid to Dean Witter are
consistent with the foregoing standard.
 
                                      A-15
<PAGE>
GENERAL INFORMATION
- --------------------------------------------------------------------------------
 
    As discussed in the Prospectus, the shareholders of the Trusts are  entitled
to  a full vote for each full share held. All of the Trustees except for Messrs.
Bozic, Purcell  and Schroeder  have  been elected  by  the shareholders  of  the
Trusts. Messrs. Bozic, Purcell and Schroeder were elected by the Trustees of the
Trusts  on April 8,  1994. The Trustees  themselves have the  power to alter the
number and  the terms  of office  of  the Trustees,  and they  may at  any  time
lengthen  their own terms or make their  terms of unlimited duration and appoint
their own successors, provided that always  at least a majority of the  Trustees
has been elected by the shareholders of the Trust. Under certain circumstances a
Trustee may be removed by action of the Trustees. The shareholders also have the
right  under certain circumstances to remove  the Trustees. The voting rights of
shareholders are not cumulative, so that holders of more than 50 percent of  the
shares  voting can, if they choose, elect all Trustees being selected, while the
holders of the remaining shares would be unable to elect any Trustees.
 
    The Declarations of Trust permit the  Trustees to authorize the creation  of
additional  series  of  shares  (the  proceeds of  which  would  be  invested in
separate, independently  managed portfolios)  and additional  classes of  shares
within  any  series (which  would be  used  to distinguish  among the  rights of
different categories of shareholders, as might be required by future regulations
or other unforeseen  circumstances). However, the  Trustees have not  authorized
any such additional series or classes of shares.
 
    The Declarations of Trust further provide that no Trustee, officer, employee
or  agent of the Trusts is  liable to any Trust or  to a shareholder, nor is any
Trustee, officer, employee or  agent liable to any  third persons in  connection
with  the affairs of any Trust, except  as such liability may arise from his/her
or its  own  bad  faith,  willful misfeasance,  gross  negligence,  or  reckless
disregard  of his/her  or its  duties. It also  provides that  all third persons
shall look solely to  a Trust's property for  satisfaction of claims arising  in
connection  with  the affairs  of that  Trust. With  the exceptions  stated, the
Declarations of Trust  provide that  a Trustee,  officer, employee  or agent  is
entitled  to be indemnified against all liability in connection with the affairs
of any Trust.
 
    The Trusts shall be of unlimited  duration subject to the provisions in  the
Declarations of Trust concerning termination by action of the shareholders.
 
CUSTODIAN AND TRANSFER AGENT
- --------------------------------------------------------------------------------
 
    The  Bank of New York, 90 Washington Street, New York, New York 10286 is the
Custodian of  the Trusts'  assets. The  Custodian has  no part  in deciding  the
Trusts'  investment policies or which securities are to be purchased or sold for
the Trusts' portfolios. Any of the  Trust's cash balances with the Custodian  in
excess  of $100,000 are unprotected by  Federal deposit insurance. Such balances
may, at times, be substantial.
 
    Dean Witter Trust  Company, Harborside Financial  Center, Plaza Two,  Jersey
City,  New Jersey 07311  is the Transfer  Agent of the  Trust's shares, Dividend
Disbursing Agent for payment of dividends and distributions on Trust shares, and
Agent for shareholders  under various  investment plans  described herein,  Dean
Witter  Trust  Company is  an affiliate  of Dean  Witter InterCapital  Inc., the
Trusts' Investment Manager, and  of Dean Witter  Distributors Inc., the  Trusts'
Distributor.  As Transfer Agent and Dividend Disbursing Agent, Dean Witter Trust
Company's responsibilities  include maintaining  shareholder accounts  including
providing  subaccounting  and  recordkeeping  services  for  certain  retirement
accounts;  disbursing  cash  dividends  and  reinvesting  dividends;  processing
account  registration  changes; handling  purchase and  redemption transactions;
mailing prospectuses  and reports;  mailing and  tabulating proxies;  processing
share  certificate transactions; and maintaining  shareholder records and lists.
For these services Dean Witter Trust Company receives a per shareholder  account
fee.
 
                                      A-16
<PAGE>
INDEPENDENT ACCOUNTANTS
- --------------------------------------------------------------------------------
 
    Price  Waterhouse LLP serves  as the independent  accountants of the Trusts.
The independent accountants  are responsible for  auditing the annual  financial
statements of the Trusts.
 
REPORTS TO SHAREHOLDERS
- --------------------------------------------------------------------------------
 
    The Trusts will send to shareholders, at least semiannually, reports showing
the  Trusts'  portfolios and  other  information. An  annual  report, containing
financial statements  audited  by  independent  accountants,  will  be  sent  to
shareholders each year.
 
    The  Trusts' fiscal years  end on June  30. The financial  statements of the
Trusts must be  audited at least  once a year  by independent accountants  whose
selection is approved annually by the Trusts' Trustees.
 
LEGAL COUNSEL
- --------------------------------------------------------------------------------
 
    Sheldon  Curtis, Esq.,  who is  an officer  and the  General Counsel  of the
Investment Manager, is an officer and the General Counsel of the Trusts.
 
EXPERTS
- --------------------------------------------------------------------------------
 
    The financial  statements of  the Trusts  included in  the Prospectuses  and
incorporated  by reference  in these  Statements of  Additional Information have
been so included and incorporated in reliance on the report of Price  Waterhouse
LLP,  independent accountants, given on the authority of said firm as experts in
auditing and accounting.
 
REGISTRATION STATEMENT
- --------------------------------------------------------------------------------
 
    These Statements  of  Additional Information  and  the Prospectuses  do  not
contain  all of  the information  set forth  in the  Registration Statements the
Trusts have  filed with  the Securities  and Exchange  Commission. The  complete
Registration  Statements  may  be  obtained  from  the  Securities  and Exchange
Commission upon payment of the fees  prescribed by the rules and regulations  of
the Commission.
 
    The Declaration of Trust establishing each Trust, a copy of which is on file
in  the office of  the Secretary of the  Commonwealth of Massachusetts, provides
that the Trust refer to the Trustees under the Declaration of Trust collectively
as Trustees, but not as individuals or personally; and no Trustee,  shareholder,
officer,  employee  or  agent  of  such Trust  shall  be  held  to  any personal
liability,  nor  shall  resort  be  had  to  their  private  property  for   the
satisfaction  of any  obligation or  claim or  otherwise in  connection with the
affairs of said Trusts but that the Trust Estate only shall be liable.
 
FINANCIAL STATEMENTS
- --------------------------------------------------------------------------------
 
   
    The audited financial  statements of each  Trust for the  fiscal year  ended
June  30, 1996, and the  report of the independent  accountants thereon, are set
forth in each Trust's Prospectus, and are incorporated herein by reference.
    
 
INFORMATION WITH RESPECT TO SECURITIES RATINGS
- --------------------------------------------------------------------------------
 
CORPORATE AND TAX-EXEMPT BOND RATINGS:
 
    The four highest ratings of Moody's Investors Service, Inc. ("Moody's")  for
tax-exempt  and  corporate  bonds are  Aaa,  Aa, A  and  Baa, all  of  which are
considered investment  grade. Bonds  rated Aaa  are judged  to be  of the  "best
quality".  The rating of Aa  is assigned to bonds which  are of "high quality by
all
 
                                      A-17
<PAGE>
standards", but  as  to which  margins  of  protection or  other  elements  make
long-term  risks appear  somewhat larger  than Aaa rated  bonds. The  Aaa and Aa
rated bonds comprise what are generally known as "high grade bonds". Bonds which
are rated A  by Moody's  possess many  favorable investment  attributes and  are
considered   "upper  medium  grade  obligations".  Factors  giving  security  to
principal and interest of  A-rated bonds are  considered adequate, but  elements
may  be present  which suggest  a susceptibility  to impairment  sometime in the
future. Bonds rated Baa are considered  as "medium grade" obligations. They  are
neither  highly protected  nor poorly  secured. Interest  payments and principal
security appear adequate for the present but certain protective elements may  be
lacking  or may be characteristically unreliable  over any great length of time.
Such  bonds  lack  outstanding  investment  characteristics  and  in  fact  have
speculative  characteristics as well. Moody's  applies numerical modifiers, 1, 2
and 3 in each rating classification for  Aa and below. The modifier 1  indicates
that  the  security ranks  in the  higher end  of its  category; the  modifier 2
indicates a mid-range ranking; and the modifier 3 indicates that the issue ranks
in the lower end of its category. The foregoing ratings are sometimes  presented
in  parentheses  preceded  with a  "con"  indicating  that the  bonds  are rated
conditionally. Bonds, the security for which depends upon the completion of some
act or the  fulfillment of some  condition, are rated  conditionally. These  are
bonds  secured by (a)  earnings of projects under  construction, (b) earnings of
projects unseasoned  in  operation  experience, (c)  rentals  which  begin  when
facilities are completed, or (d) payments to which some other limiting condition
attaches.  Such parenthetical  rating denotes  the probable  credit stature upon
completion of construction or elimination of the basis of the condition.
 
    The four  highest ratings  of  Standard &  Poor's Corporation  ("Standard  &
Poor's") for tax-exempt and corporate bonds are AAA, AA, A, and BBB all of which
are  considered  investment  grade.  Bonds rated  AAA  bear  the  highest rating
assigned by Standard & Poor's to a debt obligation, and the rating indicates  an
extremely  strong capacity  to pay principal  and interest. Bonds  rated AA also
qualify as high quality debt obligations. Capacity to pay principal and interest
is very strong, and  in the majority  of instances they  differ from AAA  issues
only  in small degree. Bonds  rated A have strong  capacity to pay principal and
interest, although they are somewhat more susceptible to the adverse effects  of
changes  in circumstances and economic conditions.  The BBB rating, which is the
lowest "investment grade"  security rating  by Standard &  Poor's, indicates  an
adequate  capacity to pay principal and  interest. Whereas they normally exhibit
adequate  protection  parameters,  adverse   economic  conditions  or   changing
circumstances  are more likely to  lead to a weakened  capacity to pay principal
and interest for bonds in  this category than for bonds  in the A category.  The
ratings for AA and below may be modified by the addition of a plus or minus sign
to  show relative  standing within  the major  rating categories.  The foregoing
ratings are sometimes  followed by  a "p", which  indicates that  the rating  is
provisional.  A  provisional rating  assumes  the successful  completion  of the
project being financed by  the bonds being rated  and indicates that payment  of
debt  service requirements is largely or  entirely dependent upon the successful
and timely completion  of the  project. This rating,  however, while  addressing
credit  quality subsequent to completion of the project, makes no comment on the
likelihood or risk of default upon failure of such completion.
 
TAX-EXEMPT NOTES
 
    The two highest  ratings of Moody's  for Notes are  MIG 1 and  MIG 2.  Notes
bearing  the designation MIG  1 are judged  to be of  the best quality, enjoying
strong protection from established  cash flows of funds  for their servicing  or
from  established and broad-based access to the market for refinancing, or both.
Notes bearing the  designation MIG  2 are  judged to  be of  high quality,  with
margins of protection ample although not so large as in the preceding group. The
ratings  of Standard  & Poor's  for Notes  are the  same as  for Bonds, although
somewhat different criteria is applied.
 
    The three highest ratings of Standard & Poor's for Notes are SP-1+, SP-1 and
SP-2. Notes  designated  SP-1+ are  determined  to possess  overwhelming  safety
characteristics   regarding  capacity  to  pay  principal  and  interest.  Notes
designated SP-1 are determined to possess very strong or strong capacity to  pay
principal  and  interest.  Notes  designated  SP-2  are  determined  to  possess
satisfactory capacity to pay principal and interest.
 
                                      A-18
<PAGE>
COMMERCIAL PAPER
 
    Moody's and  Standard  & Poor's  ratings  grades for  commercial  paper  and
short-term  Municipal Obligations,  set forth  below, are  applied to short-term
Municipal Obligations as well as taxable commercial paper.
 
    Moody's ratings are opinions of the  ability of issuers to repay  punctually
promissory obligations not having an original maturity in excess of nine months.
Moody's  employs the following  three designations, all  judged to be investment
grade, to indicate the  relative repayment capacity  of rated issuers:  Prime-1,
Highest Quality; Prime-2, Higher Quality; and Prime-3, High Quality.
 
    Standard  & Poor's  ratings are  a current  assessment of  the likelihood of
timely payment of debt having an original maturity of no more than 365 days. The
rating is not a recommendation to purchase  or sell a security. The ratings  are
based  upon current information furnished by the  issuer or obtained by S&P from
other sources it considers reliable. The  ratings may be changed, suspended,  or
withdrawn as a result of changes in or unavailability of such information.
 
    Ratings  are graded into  four categories, ranging from  "A" for the highest
quality obligations  to  "D" for  the  lowest.  Issues assigned  A  ratings  are
regarded  as having  the greatest  capacity for  timely payment.  Issues in this
category are further refined  with the designation  1, 2 and  3 to indicate  the
relative  degree of safety. The "A-1+"  and "A-1" designations indicate that the
degree of safety regarding timely payment is very strong.
 
VARIABLE RATE DEMAND OBLIGATIONS
 
    In addition to the Bond or MIG  ratings of variable rate obligations with  a
demand feature, Moody's may assign a second rating to the demand feature itself.
Such  ratings are designated as VMIG, or if  the demand feature is not rated, as
NR. Short-term ratings on issues with demand features are differentiated by  use
of  the VMIG  symbol to  reflect such  characteristics as  payment upon periodic
demand, rather  than  fixed  maturity  dates and  payment  relying  on  external
liquidity. The two highest ratings for the demand feature are VMIG 1 and VMIG 2.
These  ratings reflect  Moody's judgements regarding  the quality  of the demand
features which are identical to the  criteria involved in assigning the  ratings
MIG 1 and MIG 2, respectively, to tax-exempt Notes as discussed above.
 
                                      A-19
<PAGE>


                     ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

                            PART C  OTHER INFORMATION

Item 24.  Financial Statements and Exhibits

     (a)  FINANCIAL STATEMENTS

     (1)  Financial statements and schedules, included
          in Prospectus (Part A):                                     Page in
                                                                      Prospectus
                                                                      ----------
          Financial highlights for the period November 12,
          1991 through June 30, 1992 and for the fiscal years
          ended June 30, 1993, 1994, 1995 and 1996 .........              3

          Statement of assets and liabilities at
          June 30, 1996  ....................................             9

          Statement of operations for the year ended June
          30, 1996  .........................................             9

          Statement of changes in net assets for the
          years ended June 30, 1995 and June 30, 1996  ......             9

          Notes to Financial Statements ....................             10

          Portfolio of Investments at June 30, 1996.........             13

(2)  Financial statements included in the Statement of
          Additional Information (Part B):

          None

(3)  Financial statements included in Part C:

          None

   (b)    EXHIBITS:

          8.    -  Amendment to the Custody Agreement between the
                   Registrant and The Bank of New York

          11.   -  Consent of Independent Accountants

          16.   -  Schedule for Computation of Performance
                   Quotations

          27.   -  Financial Data Schedule

          -------------------------------
          All other exhibits were previously filed and are hereby incorporated
          by reference.


                                        1
<PAGE>


Item 25.  PERSONS CONTROLLED BY OR UNDER COMMON CONTROL WITH REGISTRANT.

          None

Item 26.  NUMBER OF HOLDERS OF SECURITIES.

           (1)                                   (2)
                                     Number of Record Holders
     Title of Class                     at August 2, 1996
     --------------                  ------------------------


Shares of Beneficial Interest                  6,299


Item 27.  INDEMNIFICATION.

     Pursuant to Section 5.3 of the Registrant's Declaration of Trust and under
Section 4.8 of the Registrant's By-Laws, the indemnification of the Registrant's
trustees, officers, employees and agents is permitted if it is determined that
they acted under the belief that their actions were in or not opposed to the
best interest of the Registrant, and, with respect to any criminal proceeding,
they had reasonable cause to believe their conduct was not unlawful.  In
addition, indemnification is permitted only if it is determined that the actions
in question did not render them liable by reason of willful misfeasance, bad
faith or gross negligence in the performance of their duties or by reason of
reckless disregard of their obligations and duties to the Registrant.  Trustees,
officers, employees and agents will be indemnified for the expense of litigation
if it is determined that they are entitled to indemnification against any
liability established in such litigation.  The Registrant may also advance money
for these expenses provided that they give their undertakings to repay the
Registrant unless their conduct is later determined to permit indemnification.

     Pursuant to Section 5.2 of the Registrant's Declaration of Trust and
paragraph 8 of the Registrant's Investment Management Agreement, neither the
Investment Manager nor any trustee, officer, employee or agent of the Registrant
shall be liable for any action or failure to act, except in the case of bad
faith, willful misfeasance, gross negligence or reckless disregard of duties to
the Registrant.

     Insofar as indemnification for liabilities arising under the Securities Act
of 1933 (the "Act") may be permitted to trustees, officers and controlling
persons of the Registrant pursuant to the foregoing provisions or otherwise, the
Registrant has been advised that in the opinion of the  Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable.  In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a trustee, officer, or controlling person of the Registrant
in connection with the successful defense of any action, suit or proceeding) is
asserted against the Registrant by such trustee, officer or controlling person
in connection with the shares being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the


                                        2
<PAGE>

question whether such indemnification by it is against public policy as
expressed in the Act, and will be governed by the final adjudication of such
issue.

     The Registrant hereby undertakes that it will apply the indemnification
provision of its by-laws in a manner consistent with Release 11330 of the
Securities and Exchange Commission under the Investment Company Act of 1940, so
long as the interpretation of Sections 17(h) and 17(i) of such Act remains in
effect.

     Registrant, in conjunction with the Investment Manager, Registrant's
Trustees, and other registered investment management companies managed by the
Investment Manager, maintains insurance on behalf of any person who is or was a
Trustee, officer, employee, or agent of Registrant, or who is or was serving at
the request of Registrant as a trustee, director, officer, employee or agent of
another trust or corporation, against any liability asserted against him and
incurred by him or arising out of his position.  However, in no event will
Registrant maintain insurance to indemnify any such person for any act for which
Registrant itself is not permitted to indemnify him.


Item 28. BUSINESS AND OTHER CONNECTIONS OF INVESTMENT ADVISER.

     See "The Fund and Its Management" in the Prospectus regarding the business
of the investment adviser.  The following information is given regarding
officers of Dean Witter InterCapital Inc.  InterCapital is a wholly-owned
subsidiary of Dean Witter, Discover & Co.  The principal address of the Dean
Witter Funds is Two World Trade Center, New York, New York 10048.

     The term "Dean Witter Funds" used below refers to the following registered
investment companies:

CLOSED-END INVESTMENT COMPANIES
 (1) InterCapital Income Securities Inc.
 (2) High Income Advantage Trust
 (3) High Income Advantage Trust II
 (4) High Income Advantage Trust III
 (5) Municipal Income Trust
 (6) Municipal Income Trust II
 (7) Municipal Income Trust III
 (8) Dean Witter Government Income Trust
 (9) Municipal Premium Income Trust
(10) Municipal Income Opportunities Trust
(11) Municipal Income Opportunities Trust II
(12) Municipal Income Opportunities Trust III
(13) Prime Income Trust
(14) InterCapital Insured Municipal Bond Trust
(15) InterCapital Quality Municipal Income Trust
(16) InterCapital Quality Municipal Investment Trust
(17) InterCapital Insured Municipal Income Trust
(18) InterCapital California Insured Municipal Income Trust
(19) InterCapital Insured Municipal Trust
(20) InterCapital Quality Municipal Securities
(21) InterCapital New York Quality Municipal Securities
(22) InterCapital California Quality Municipal Securities


                                        3
<PAGE>

(23) InterCapital Insured California Municipal Securities
(24) InterCapital Insured Municipal Securities

OPEN-END INVESTMENT COMPANIES:
 (1) Dean Witter Short-Term Bond Fund
 (2) Dean Witter Tax-Exempt Securities Trust
 (3) Dean Witter Tax-Free Daily Income Trust
 (4) Dean Witter Dividend Growth Securities Inc.
 (5) Dean Witter Convertible Securities Trust
 (6) Dean Witter Liquid Asset Fund Inc.
 (7) Dean Witter Developing Growth Securities Trust
 (8) Dean Witter Retirement Series
 (9) Dean Witter Federal Securities Trust
(10) Dean Witter World Wide Investment Trust
(11) Dean Witter U.S. Government Securities Trust
(12) Dean Witter Select Municipal Reinvestment Fund
(13) Dean Witter High Yield Securities Inc.
(14) Dean Witter Intermediate Income Securities
(15) Dean Witter New York Tax-Free Income Fund
(16) Dean Witter California Tax-Free Income Fund
(17) Dean Witter Health Sciences Trust
(18) Dean Witter California Tax-Free Daily Income Trust
(19) Dean Witter Global Asset Allocation Fund
(20) Dean Witter American Value Fund
(21) Dean Witter Strategist Fund
(22) Dean Witter Utilities Fund
(23) Dean Witter World Wide Income Trust
(24) Dean Witter New York Municipal Money Market Trust
(25) Dean Witter Capital Growth Securities
(26) Dean Witter Precious Metals and Minerals Trust
(27) Dean Witter European Growth Fund Inc.
(28) Dean Witter Global Short-Term Income Fund Inc.
(29) Dean Witter Pacific Growth Fund Inc.
(30) Dean Witter Multi-State Municipal Series Trust
(31) Dean Witter Premier Income Trust
(32) Dean Witter Short-Term U.S. Treasury Trust
(33) Dean Witter Diversified Income Trust
(34) Dean Witter U.S. Government Money Market Trust
(35) Dean Witter Global Dividend Growth Securities
(36) Active Assets California Tax-Free Trust
(37) Dean Witter Natural Resource Development Securities Inc.
(38) Active Assets Government Securities Trust
(39) Active Assets Money Trust
(40) Active Assets Tax-Free Trust
(41) Dean Witter Limited Term Municipal Trust
(42) Dean Witter Variable Investment Series
(43) Dean Witter Value-Added Market Series
(44) Dean Witter Global Utilities Fund
(45) Dean Witter High Income Securities
(46) Dean Witter National Municipal Trust
(47) Dean Witter International SmallCap Fund
(48) Dean Witter Mid-Cap Growth Fund
(49) Dean Witter Select Dimensions Investment Series
(50) Dean Witter Balanced Growth Fund



                                        4
<PAGE>

(51) Dean Witter Balanced Income Fund
(52) Dean Witter Hawaii Municipal Trust
(53) Dean Witter Capital Appreciation Fund
(54) Dean Witter Intermediate Term U.S. Treasury Trust
(55) Dean Witter Information Fund
(56) Dean Witter Japan Fund
(57) Dean Witter Income Builder Fund

The term "TCW/DW Funds" refers to the following registered investment companies:

OPEN-END INVESTMENT COMPANIES
 (1) TCW/DW Core Equity Trust
 (2) TCW/DW North American Government Income Trust
 (3) TCW/DW Latin American Growth Fund
 (4) TCW/DW Income and Growth Fund
 (5) TCW/DW Small Cap Growth Fund
 (6) TCW/DW Balanced Fund
 (7) TCW/DW Total Return Trust
 (8) TCW/DW Mid-Cap Equity Trust
 (9) TCW/DW Global Telecom Trust


CLOSED-END INVESTMENT COMPANIES
 (1) TCW/DW Term Trust 2000
 (2) TCW/DW Term Trust 2002
 (3) TCW/DW Term Trust 2003
 (4) TCW/DW Emerging Markets Opportunities Trust


NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Charles A. Fiumefreddo        Executive Vice President and Director of Dean
Chairman, Chief               Witter Reynolds Inc. ("DWR"); Chairman, Chief
Executive Officer and         Executive Officer and Director of Dean Witter
Director                      Distributors Inc. ("Distributors") and Dean
                              Witter Services Company Inc. ("DWSC"); Chairman
                              and Director of Dean Witter Trust Company
                              ("DWTC"); Chairman, Director or Trustee, President
                              and Chief Executive Officer of the Dean Witter
                              Funds and Chairman, Chief Executive Officer and
                              Trustee of the TCW/DW Funds; Formerly Executive
                              Vice President and Director of Dean Witter,
                              Discover & Co. ("DWDC"); Director and/or officer
                              of various DWDC subsidiaries.

Philip J. Purcell             Chairman, Chief Executive Officer and Director of
Director                      of DWDC and DWR; Director of DWSC and
                              Distributors; Director or Trustee of the Dean
                              Witter Funds; Director and/or officer of various
                              DWDC subsidiaries.


                                        5
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Richard M. DeMartini          Executive Vice President of DWDC; President and
Director                      Chief Operating Officer of Dean Witter Capital;
                              Director of DWR, DWSC, Distributors and DWTC;
                              Trustee of the TCW/DW Funds; Member (since
                              January, 1993) and Chairman (since January, 1995)
                              of the Board of Directors of NASDAQ.

James F. Higgins              Executive Vice President of DWDC; President and
Director                      Chief Operating Officer of Dean Witter Financial;
                              Director of DWR, DWSC, Distributors and DWTC.

Thomas C. Schneider           Executive Vice President and Chief Financial
Executive Vice                Officer of DWDC, DWR, DWSC and Distributors;
President, Chief              Director of DWR, DWSC and Distributors.
Financial Officer and
Director

Christine A. Edwards          Executive Vice President, Secretary and General
Director                      Counsel of DWDC and DWR; Executive Vice President,
                              Secretary and Chief Legal Officer of Distributors;
                              Director of DWR, DWSC and Distributors.

Robert M. Scanlan             President and Chief Operating Officer of DWSC,
President and Chief           Executive Vice President of Distributors;
Operating Officer             Executive Vice President and Director of DWTC;
                              Vice President of the Dean Witter Funds and the
                              TCW/DW Funds.

David A. Hughey               Executive Vice President and Chief Administrative
Executive Vice                Officer of DWSC, Distributors and DWTC; Director
President and Chief           of DWTC; Vice President of the Dean Witter Funds
Administrative Officer        and the TCW/DW Funds.

John Van Heuvelen             President, Chief Operating Officer and Director
Executive Vice                of DWTC.
President

Joseph J. McAlinden
Executive Vice President
and Chief Investment
Officer                       Vice President of the Dean Witter Funds and
                              Director of DWTC.

Sheldon Curtis                Assistant Secretary of DWR; Senior Vice President,
Senior Vice President,        Secretary and General Counsel of DWSC; Senior Vice
General Counsel and           President, Assistant General Counsel and Assistant
Secretary                     Secretary of Distributors; Senior Vice President
                              and Secretary of DWTC; Vice President, Secretary
                              and General Counsel of the Dean Witter Funds and
                              the TCW/DW Funds.


                                        6
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Peter M. Avelar
Senior Vice President         Vice President of various Dean Witter Funds.

Mark Bavoso
Senior Vice President         Vice President of various Dean Witter Funds.

Richard Felegy
Senior Vice President

Edward Gaylor
Senior Vice President         Vice President of various Dean Witter Funds.

Robert S. Giambrone
Senior Vice President         Senior Vice President of DWSC, Distributors and
                              DWTC and Director of DWTC; Vice President of the
                              Dean Witter Funds and the TCW/DW Funds.

Rajesh K. Gupta
Senior Vice President         Vice President of various Dean Witter Funds.

Kenton J. Hinchcliffe
Senior Vice President         Vice President of various Dean Witter Funds.

Kevin Hurley
Senior Vice President         Vice President of various Dean Witter Funds.


John B. Kemp, III             Director of the Provident Savings Bank, Jersey
Senior Vice President         City, New Jersey.

Anita Kolleeny
Senior Vice President         Vice President of various Dean Witter Funds.

Jonathan R. Page
Senior Vice President         Vice President of various Dean Witter Funds.

Ira N. Ross
Senior Vice President         Vice President of various Dean Witter Funds.

Rochelle G. Siegel
Senior Vice President         Vice President of various Dean Witter Funds.

Paul D. Vance
Senior Vice President         Vice President of various Dean Witter Funds.

Elizabeth A. Vetell
Senior Vice President

James F. Willison
Senior Vice President         Vice President of various Dean Witter Funds.


                                        7
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Ronald J. Worobel
Senior Vice President         Vice President of various Dean Witter Funds.

Thomas F. Caloia              First Vice President and Assistant Treasurer of
First Vice President          DWSC, Assistant Treasurer of Distributors;
and Assistant                 Treasurer and Chief Financial Officer of the
Treasurer                     Dean Witter Funds and the TCW/DW Funds.

Marilyn K. Cranney            Assistant Secretary of DWR; First Vice President
First Vice President          and Assistant Secretary of DWSC; Assistant
and Assistant Secretary       Secretary of the Dean Witter Funds and the TCW/DW
                              Funds.

Barry Fink                    First Vice President and Assistant Secretary of
First Vice President          DWSC; Assistant Secretary of the Dean Witter
and Assistant Secretary       Funds and the TCW/DW Funds.

Michael Interrante            First Vice President and Controller of DWSC;
First Vice President          Assistant Treasurer of Distributors;First Vice
and Controller                President and Treasurer of DWTC.

Robert Zimmerman
First Vice President

Joan Allman
Vice President

Joseph Arcieri
Vice President                Vice President of various Dean Witter Funds.

Kirk Balzer
Vice President                Vice President of Dean Witter Mid-Cap Growth Fund

Douglas Brown
Vice President

Philip Casparius
Vice President

Thomas Chronert
Vice President

Rosalie Clough
Vice President

Patricia A. Cuddy
Vice President                Vice President of various Dean Witter Funds.

B. Catherine Connelly
Vice President


                                        8
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Salvatore DeSteno
Vice President                Vice President of DWSC.

Frank J. DeVito
Vice President                Vice President of DWSC.

Dwight Doolan
Vice President

Bruce Dunn
Vice President

Jeffrey D. Geffen
Vice President

Deborah Genovese
Vice President

Peter W. Gurman
Vice President

John Hechtlinger
Vice President

Peter Hermann
Vice President                Vice President of various Dean Witter Funds

Elizabeth Hinchman
Vice President

David Hoffman
Vice President

David Johnson
Vice President

Christopher Jones
Vice President

James Kastberg
Vice President

Stanley Kapica
Vice President

Michael Knox
Vice President                Vice President of various Dean Witter Funds



                                        9
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Konrad J. Krill
Vice President                Vice President of various Dean Witter Funds.

Paula LaCosta
Vice President                Vice President of various Dean Witter Funds.

Thomas Lawlor
Vice President

Gerard Lian
Vice President                Vice President of various Dean Witter Funds.

LouAnne D. McInnis            Vice President and Assistant Secretary of DWSC;
Vice President and            Assistant Secretary of the Dean Witter Funds and
Assistant Secretary           the TCW/DW Funds.

Sharon K. Milligan
Vice President

Julie Morrone
Vice President

David Myers
Vice President

James Nash
Vice President

Richard Norris
Vice President

Anne Pickrell
Vice President                Vice President of Dean Witter Global Short-
                              Term Income Fund Inc.

Hugh Rose
Vice President

Robert Rossetti
Vice President

Ruth Rossi                    Vice President and Assistant Secretary of DWSC;
Vice President and            Assistant Secretary of the Dean Witter Funds and
Assistant Secretary           the TCW/DW Funds.

Carl F. Sadler
Vice President



                                       10
<PAGE>

NAME AND POSITION             OTHER SUBSTANTIAL BUSINESS, PROFESSION, VOCATION
WITH DEAN WITTER              OR EMPLOYMENT, INCLUDING NAME, PRINCIPAL ADDRESS
INTERCAPITAL INC.             AND NATURE OF CONNECTION
- -----------------             ------------------------------------------------

Rafael Scolari
Vice President                Vice President of Prime Income Trust

Peter Seeley                  Vice President of Dean Witter World
Vice President                Wide Income Trust

Jayne M. Stevlingson
Vice President                Vice President of various Dean Witter Funds.

Kathleen Stromberg
Vice President                Vice President of various Dean Witter Funds.

Vinh Q. Tran
Vice President                Vice President of various Dean Witter Funds.

Alice Weiss
Vice President                Vice President of various Dean Witter Funds.



Item 29.    PRINCIPAL UNDERWRITERS

     (a)  Dean Witter Distributors Inc. ("Distributors"), a Delaware
          corporation, is the principal underwriter of the Registrant.
          Distributors is also the principal underwriter of the following
          investment companies:

 (1)           Dean Witter Liquid Asset Fund Inc.
 (2)           Dean Witter Tax-Free Daily Income Trust
 (3)           Dean Witter California Tax-Free Daily Income Trust
 (4)           Dean Witter Retirement Series
 (5)           Dean Witter Dividend Growth Securities Inc.
 (6)           Dean Witter Global Asset Allocation
 (7)           Dean Witter World Wide Investment Trust
 (8)           Dean Witter Capital Growth Securities
 (9)           Dean Witter Convertible Securities Trust
(10)           Active Assets Tax-Free Trust
(11)           Active Assets Money Trust
(12)           Active Assets California Tax-Free Trust
(13)           Active Assets Government Securities Trust
(14)           Dean Witter Short-Term Bond Fund
(15)           Dean Witter Mid-Cap Growth Fund
(16)           Dean Witter U.S. Government Securities Trust
(17)           Dean Witter High Yield Securities Inc.
(18)           Dean Witter New York Tax-Free Income Fund
(19)           Dean Witter Tax-Exempt Securities Trust
(20)           Dean Witter California Tax-Free Income Fund
(21)           Dean Witter Limited Term Municipal Trust
(22)           Dean Witter Natural Resource Development Securities Inc.
(23)           Dean Witter World Wide Income Trust
(24)           Dean Witter Utilities Fund
(25)           Dean Witter Strategist Fund


                                       11
<PAGE>

(26)           Dean Witter New York Municipal Money Market Trust
(27)           Dean Witter Intermediate Income Securities
(28)           Prime Income Trust
(29)           Dean Witter European Growth Fund Inc.
(30)           Dean Witter Developing Growth Securities Trust
(31)           Dean Witter Precious Metals and Minerals Trust
(32)           Dean Witter Pacific Growth Fund Inc.
(33)           Dean Witter Multi-State Municipal Series Trust
(34)           Dean Witter Federal Securities Trust
(35)           Dean Witter Short-Term U.S. Treasury Trust
(36)           Dean Witter Diversified Income Trust
(37)           Dean Witter Health Sciences Trust
(38)           Dean Witter Global Dividend Growth Securities
(39)           Dean Witter American Value Fund
(40)           Dean Witter U.S. Government Money Market Trust
(41)           Dean Witter Global Short-Term Income Fund Inc.
(42)           Dean Witter Premier Income Trust
(43)           Dean Witter Value-Added Market Series
(44)           Dean Witter Global Utilities Fund
(45)           Dean Witter High Income Securities
(46)           Dean Witter National Municipal Trust
(47)           Dean Witter International SmallCap Fund
(48)           Dean Witter Balanced Growth Fund
(49)           Dean Witter Balanced Income Fund
(50)           Dean Witter Hawaii Municipal Trust
(51)           Dean Witter Variable Investment Series
(52)           Dean Witter Capital Appreciation Fund
(53)           Dean Witter Intermediate Term U.S. Treasury Trust
(54)           Dean Witter Information Fund
(55)           Dean Witter Japan Fund
(56)           Dean Witter Income Builder Fund
 (1)           TCW/DW Core Equity Trust
 (2)           TCW/DW North American Government Income Trust
 (3)           TCW/DW Latin American Growth Fund
 (4)           TCW/DW Income and Growth Fund
 (5)           TCW/DW Small Cap Growth Fund
 (6)           TCW/DW Balanced Fund
 (7)           TCW/DW Total Return Trust
 (8)        TCW/DW Mid-Cap Equity Trust
 (9)           TCW/DW Global Telecom Trust

     (b)  The following information is given regarding directors and officers of
Distributors not listed in Item 28 above.  The principal address of Distributors
is Two World Trade Center, New York, New York 10048.  None of the following
persons has any position or office with the Registrant.

                                Positions and
                                Office with
Name                            Distributors
- ----                            -------------
Fredrick K. Kubler              Senior Vice President, Assistant
                                Secretary and Chief Compliance
                                Officer.

Michael T. Gregg                Vice President and Assistant


                                       12
<PAGE>


                                Secretary.

Item 30.    LOCATION OF ACCOUNTS AND RECORDS

       All accounts, books and other documents required to be maintained by
Section 31(a) of the Investment Company Act of 1940 and the Rules thereunder are
maintained by the Investment Manager at its offices, except records relating to
holders of shares issued by the Registrant, which are maintained by the
Registrant's Transfer Agent, at its place of business as shown in the
prospectus.


Item 31.    MANAGEMENT SERVICES

        Registrant is not a party to any such management-related service
contract.

Item 32.    UNDERTAKINGS

        Registrant hereby undertakes to furnish each person to whom a prospectus
is delivered with a copy of the Registrant's latest annual report to
shareholders, upon request and without charge.


                                       13
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933 and the
Investment Company Act of 1940, the Registrant certifies that it meets all of
the requirements for effectiveness of this Registration Statement pursuant to
Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-
Effective Amendment to the Registration Statement to be signed on its behalf by
the undersigned, thereunto duly authorized, in the City of New York and State of
New York on the 22nd day of August, 1996.

                                   ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

                                       By  /s/ Sheldon Curtis
                                           ------------------
                                              Sheldon Curtis
                                           Vice President and Secretary

     Pursuant to the requirements of the Securities Act of 1933, this Post-
Effective Amendment No. 18 has been signed below by the following persons in the
capacities and on the dates indicated.

     Signatures                    Title                     Date
     ----------                    -----                     ----

(1) Principal Executive Officer    President, Chief
                                   Executive Officer,
                                   Trustee and Chairman
By   /s/ Charles A. Fiumefreddo                              08/22/96
    ---------------------------
         Charles A. Fiumefreddo

(2) Principal Financial Officer    Treasurer and Principal
                                   Accounting Officer

By   /s/ Thomas F. Caloia                                    08/22/96
    ---------------------------
         Thomas F. Caloia

(3) Majority of the Trustees

    Charles A. Fiumefreddo (Chairman)
    Philip J. Purcell

By   /s/ Sheldon Curtis                                      08/22/96
    ---------------------------
         Sheldon Curtis
         Attorney-in-Fact


    Michael Bozic              Manuel H. Johnson
    Edwin J. Garn              Michael E. Nugent
    John R. Haire              John L. Schroeder


By  /s/ David M. Butowsky                                    08/22/96
    ---------------------------
        David M. Butowsky
        Attorney-in-Fact

<PAGE>

                                  EXHIBIT INDEX

          8.    -  Amendment to the Custody Agreement between the
                   Registrant and The Bank of New York

          11.   -  Consent of Independent Accountants

          16.   -  Schedule for Computation of Performance
                   Quotations

          27.   -  Financial Data Schedule


          -------------------------
          All other exhibits were previously filed and are hereby incorporated
          by reference.

<PAGE>
                         AMENDMENT TO CUSTODY AGREEMENT


     Amendment made as of this 17th day of April, 1996 by and between Active 
Assets California Tax-Free Trust (the "Fund") and The Bank of New York (the 
"Custodian") to the Custody Agreement between the Fund and the Custodian 
dated September 20, 1991 (the "Custody Agreement").  The Custody Agreement is 
hereby amended as follows:

     Article XV Section 8 of the Custody Agreement shall be deleted and be
replaced by Sections 8.(a), 8.(b) and 8.(c) as set forth below:

     "8.  (a)  The Custodian will use reasonable care with respect to its 
obligations under this Agreement and the safekeeping of Securities and moneys 
owned by the Fund.  The Custodian shall indemnify the Fund against and save 
the Fund harmless from all liability, claims, losses and demands whatsoever, 
including attorneys' fees, howsoever arising or incurred as the result of the 
failure of a subcustodian which is a banking insitution located in a foreign 
country and identified on Schedule A attached hereto and as amended from time 
to time upon mutual agreement of the parties (each, a "Subcustodian") to 
exercise reasonable care with respect to the safekeeping of such Securities 
and moneys to the same extent that the Custodian would be liable to the Fund 
if the Custodian were holding such securities and moneys in New York.  In the 
event of any loss to the Fund by reason of the failure of the Custodian or a 
Subcustodian to utilize reasonable care, the Custodian shall be liable to the 
Fund only to the extent of the Fund's direct damages, to be determined based 
on the market value of the Securities and moneys which are the subject of the 
loss at the date of discovery of such loss and without reference to any 
special conditions or circumstances.

     8.  (b)  The Custodian shall not be liable for any loss which results from
(i) the general risk of investing, or (ii) investing or holding Securities and
moneys in a particular country including, but not limited to, losses resulting
from nationalization, expropriation or other governmental actions; regulation of
the banking or securities industry; currency restrictions, devaluations or
fluctuations; or market conditions which prevent the orderly execution of
securities transactions or affect the value of Securities or moneys.

     8.  (c)  Neither party shall be liable to the other for any loss due to
forces beyond its control including, but not limited to, strikes or work
stoppages, acts of war or terrorism, insurrection, revolution, nuclear fusion,
fission or radiation, or acts of God."

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed by their respective Officers, thereunto duly authorized and their
respective seals to be hereunto affixed, as of the day and year first above
written.


                         ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST


[SEAL]                                       By:  /s/ David A. Hughey
                                                ------------------------

Attest:


/s/ Robert M. Scanlan
- ------------------------

                                             THE BANK OF NEW YORK


[SEAL]                                       By: /s/ Steve Grunston
                                                ---------------------

Attest:


/s/ Vincent Blazewitcz
- ------------------------

<PAGE>

                         SCHEDULE A


COUNTRY/MARKET                     SUBCUSTODIAN
- --------------                     ------------

Argentina                          The Bank of Boston
Australia                          ANZ Banking Group Limited
Austria                            Girocredit Bank AG
Bangladesh*                        Standard Chartered Bank
Belgium                            Banque Bruxelles Lambert
Botswana*                          Stanbic Bank Botswana Ltd.
Brazil                             The Bank of Boston
Canada                             Royal Trust/Royal Bank of Canada
Chile                              The Bank of Boston/Banco de Chile
China                              Standard Chartered Bank
Colombia                           Citibank, N.A.
Denmark                            Den Danske Bank
Euromarket                         CEDEL
                                   Euroclear
                                   First Chicago Clearing Centre
Finland                            Union Bank of Finland
France                             Banque Paribas/Credit Commercial de France
Germany                            Dresdner Bank A.G.
Ghana*                             Merchant Bank Ghana Ltd.
Greece                             Alpha Credit Bank
Hong Kong                          Hong Kong and Shanghai Banking Corp.
Indonesia                          Hong Kong and Shanghai Banking Corp.
Ireland                            Allied Irish Bank
Israel                             Israel Discount Bank
Italy                              Banca Commerciale Italiana
Japan                              Yasuda Trust & Banking Co., Lt.
Korea                              Bank of Seoul
Luxembourg                         Kredietbank S.A.
Malaysia                           Hong Kong Bank Malaysia Berhad
Mexico                             Banco Nacional de Mexico (Banamex)
Netherlands                        Mees Pierson
New Zealand                        ANZ Banking Group Limited
Norway                             Den Norske Bank
Pakistan                           Standard Chartered Bank
Peru                               Citibank, N.A.
Philippines                        Hong Kong and Shanghai Banking Corp.
Poland                             Bank Handlowy w Warsawie
Portugal                           Banco Comercial Portugues
Singapore                          United Overseas Bank
South Africa                       Standard Bank of South Africa Limited
Spain                              Banco Bilbao Vizcaya
Sri Lanka                          Standard Chartered Bank

<PAGE>

                         SCHEDULE A

COUNTRY/MARKET                     SUBCUSTODIAN
- --------------                     ------------

Sweden                             Skandinaviska Enskilda Banken
Switzerland                        Union Bank of Switzerland
Taiwan                             Hong Kong and Shanghai Banking Corp.
Thailand                           Siam Commercial Bank
Turkey                             Citibank, N.A.
United Kingdom                     The Bank of New York
United States                      The Bank of New York
Uruguay                            The Bank of Boston
Venezuela                          Citibank N.A.
Zimbabwe*                          Stanbic Bank Zimbabwe Ltd.



















*Not yet 17(f)5 compliant

<PAGE>
CONSENT OF INDEPENDENT ACCOUNTANTS


We hereby consent to the use in the Prospectus constituting part of this 
Post-Effective Amendment No. 6 to the registration statement on Form N-1A 
(the "Registration Statement") of our report dated August 7, 1996, relating 
to the financial statements and financial highlights of Dean Witter Active 
Assets California Tax-Free Trust, which appears in such Prospectus.  We also 
consent to the reference to us under the heading "Financial Highlights" in 
such Prospectus and to the references to us under the headings "Independent 
Accountants" and "Experts" in the Statement of Additional Information 
constituting part of this Registration Statement.

/s/Price Waterhouse LLP
PRICE WATERHOUSE LLP
1177 Avenue of the Americas
New York, New York 10036
August 22, 1996

<PAGE>
                 ACTIVE ASSETS CALIFORNIA TAX-FREE

     Exhibit 16: Schedule for computation of each performance
     quotation provided in the Statement of Additional Information.

(16) The Trust's current yield for the seven days ending
     June 30, 1996

     (A - B) x 365/N

     (1.000519 - 1) x 365/7   =  2.71%

     The Trust's effective annualized yield for the seven days ending
     June 30, 1996

        365/N
     A               - 1
           365/7
     1.000519             - 1 = 2.74%

     A = Value of a share of the Trust at end of period.
     B = Value of a share of the Trust at beginning of period.
     N = Number of days in the period.

CALCULATION
                                 Tax equivalent Yield = 2.71% Based on a tax
(1.000519 - 1) x 365/7                                = bracket of 46.24%
    =             2.71%

((1.000519) x 52.14285714 - 1)
    =             2.74%

TAX BRACKET: 46.24%

FORMULA (CURRENT 7 DAY YIELD/1 - 46.24)
CURRENT 7 DAY YIELD: 2.71
2.71/.5376
Tax equivalent Yield = 5.04%

<TABLE> <S> <C>

<PAGE>
<ARTICLE> 6
       
<S>                             <C>
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          JUN-30-1996
<PERIOD-START>                             JUL-01-1995
<PERIOD-END>                               JUN-30-1996
<INVESTMENTS-AT-COST>                      430,773,691
<INVESTMENTS-AT-VALUE>                     430,773,691
<RECEIVABLES>                                2,297,311
<ASSETS-OTHER>                               1,237,742
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                             434,308,744
<PAYABLE-FOR-SECURITIES>                    49,813,510
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                      277,070
<TOTAL-LIABILITIES>                         50,090,580
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                   384,229,943
<SHARES-COMMON-STOCK>                      384,229,943
<SHARES-COMMON-PRIOR>                      313,583,094
<ACCUMULATED-NII-CURRENT>                           85
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                       (11,864)
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                             0
<NET-ASSETS>                               384,218,164
<DIVIDEND-INCOME>                                    0
<INTEREST-INCOME>                           12,316,979
<OTHER-INCOME>                                       0
<EXPENSES-NET>                               2,376,358
<NET-INVESTMENT-INCOME>                      9,940,621
<REALIZED-GAINS-CURRENT>                         5,093
<APPREC-INCREASE-CURRENT>                            0
<NET-CHANGE-FROM-OPS>                        9,945,714
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                  (9,940,586)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                  1,301,311,516
<NUMBER-OF-SHARES-REDEEMED>            (1,240,605,253)
<SHARES-REINVESTED>                          9,940,586
<NET-CHANGE-IN-ASSETS>                      70,651,977
<ACCUMULATED-NII-PRIOR>                             50
<ACCUMULATED-GAINS-PRIOR>                     (16,957)
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                        1,781,282
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                              2,397,932
<AVERAGE-NET-ASSETS>                       358,213,890
<PER-SHARE-NAV-BEGIN>                             1.00
<PER-SHARE-NII>                                  0.028
<PER-SHARE-GAIN-APPREC>                              0
<PER-SHARE-DIVIDEND>                           (0.028)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               1.00
<EXPENSE-RATIO>                                   0.67
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>


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