UNIT CORP
8-A12B, 1995-05-23
DRILLING OIL & GAS WELLS
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<PAGE>
 
================================================================================

                                 UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                   FORM 8-A

               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                    PURSUANT TO SECTION 12(b) OR (g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

                               UNIT CORPORATION
             (Exact name of registrant as specified in its charter)

       Delaware                                        73-1283193
State of incorporation                              (I.R.S. employer
   or organization)                              identification number)
1000 Kensington Tower I
   7130 South Lewis
   Tulsa, Oklahoma                                       74136
 (Address of principal                                (Zip code)
   executive offices)

Securities to be registered pursuant to Section 12(b) of the Act:

  Title of each class                          Name of each exchange on
  to be so registered                                   which
                                                 each class is to be
                                                      registered

  Rights to Purchase                           New York Stock Exchange
Series A Participating
      Cumulative
   Preferred stock

Securities to be registered pursuant to Section 12(g) of the Act:

                                     None

                               (Title of Class)

                   Page 1 of 80 sequentially numbered pages.
                          Exhibit Index is at page 7.

================================================================================

                                 Page 1 of 80

<PAGE>
 
Item 1.  Description of Securities to be Registered.

          As of May 19, 1995, the Board of Directors of Unit Corporation (the
          "COMPANY") declared a dividend of one preferred stock purchase right
          (Right) for each outstanding share of Common stock, par value $0.20
          per share, of the Company (the "COMMON SHARES"). The Rights will be
          issued to the holders of record of Common Shares outstanding on
          May 31, 1995, and with respect to Common Shares issued thereafter
          until the Distribution Date (as defined below) and, in certain
          circumstances, with respect to Common Shares issued after the
          Distribution Date. Each Right, when it becomes exercisable as
          described below, will entitle the registered holder to purchase from
          the Company one one-hundredth (1/100th) of a share of Series A
          Participating Cumulative Preferred Stock, par value $1.00 per share,
          of the company (the "PREFERRED SHARES") at a price of $12.75 (the
          "PURCHASE PRICE"). The description and terms of the Rights are set
          forth in a Rights Agreement dated as of May 19, 1995 (the "RIGHTS
          AGREEMENT"), between the Company and Chemical Bank, as Rights Agent
          (the "RIGHTS AGENT").

          Until the earlier of (i) the tenth day after the Company learns that a
          person or group (including any affiliate or associate of such person
          or group) has acquired, or has obtained the right to acquire,
          beneficial ownership of more than 15% of the outstanding Common Shares
          (such person or group being an "ACQUIRING PERSON"), and (ii) the tenth
          Business Day (or such later date as may be designated by the Board of
          Directors of the Company) following the commencement of, or first
          public disclosure of an intent to commence, a tender or exchange offer
          for outstanding Common Shares which could result in such person or
          group becoming the beneficial owner of more than 15% of the
          outstanding Common Shares (the earlier of such dates being called the
          "DISTRIBUTION DATE"), the Rights will be evidenced by the certificates
          for Common Shares registered in the names of the holders thereof
          (which certificates for Common Shares shall also be deemed to be Right
          Certificates, as defined below) and not by separate Right
          Certificates.  Therefore, until the Distribution Date, the Rights will
          be transferred with and only with the Common Shares.

          As soon as practicable following the Distribution Date, separate
          certificates evidencing the Rights ("RIGHT CERTIFICATES") will be
          mailed to holders of record of the Common Shares as of the close of
          business on the Distribution Date (and to each initial record holder
          of certain Common Shares originally issued after the Distribution
          Date), and such separate Right Certificates alone will thereafter
          evidence the Rights.

          The Rights are not exercisable until the Distribution Date and will
          expire on May 19, 2005 (the "EXPIRATION DATE") unless earlier redeemed
          by the Company as described below.

                                 Page 2 of 80
<PAGE>
 
          The number of Preferred Shares or other securities issuable upon
          exercise of a Right, the Purchase Price, the Redemption Price (as
          defined below) and the number of Rights associated with each
          outstanding Common Share are all subject to adjustment by the Board of
          Directors of the Company in the event of any change in the Common
          Shares or the Preferred Shares, whether by reason of stock dividends,
          stock splits, recapitalization, mergers, consolidations, combinations
          or exchanges of securities, split-ups, split-offs, spin-offs,
          liquidations, other similar changes in capitalization, any
          distribution or issuance of cash, assets, evidences of indebtedness or
          subscription rights, options or warrants to holder of Common Shares or
          Preferred Shares, as the case may be (other than distribution of the
          Rights or regular quarterly cash dividends) or otherwise.

          The Preferred Shares are authorized to be issued in fractions which
          are an integral multiple of one one-hundredth (1/100th) of a Preferred
          Share.  The Company may, but is not required to, issue fractions of
          shares upon the exercise of Rights, and, in lieu of fractional shares,
          the Company may issue certificates or utilize a depository arrangement
          as provided by the terms of the Preferred Shares and, in the case of
          fractions other than one one-hundredth (1/100th) of a Preferred Share
          or integral multiples thereof, may make a cash payment based on the
          market price of such shares.

          At such time there is an Acquiring Person, the Rights will entitle
          each holder (other than such Acquiring Person (or any affiliate or
          associate of such Acquiring Person)) of a Right to purchase, for the
          Purchase Price, that number of one one-hundredths (1/100th) of a
          Preferred Share equivalent to the number of Common Shares which at the
          time of such event would have a market value of twice the Purchase
          Price.

          In the event the Company is acquired in a merger or other business
          combination by an Acquiring Person or an associate or affiliate of an
          Acquiring Person that is a publicly traded corporation or 50% or more
          of the Company's assets or assets representing 50% or more of the
          Company's revenues or cash flow are sold, leased, exchanged or
          otherwise transferred (in one or more transactions) to an Acquiring
          Person or an associate or affiliate of an Acquiring Person that is a
          publicly traded corporation, each Right will entitle its holder
          (subject to the next paragraph) to purchase, for the Purchase Price,
          that number of common shares of such corporation which at the time of
          the transaction would have a market value of twice the Purchase Price.
          In the event the Company is acquired in a merger or other business
          combination by an Acquiring Person or an associate or affiliate of an
          Acquiring Person that is not a publicly traded entity or 50% or more
          of the Company's assets or assets representing 50% or more of the
          Company's revenues or cash flow are sold, leased, exchanged or

                                 Page 3 of 80
<PAGE>
 
          otherwise transferred (in one or more transactions) to an Acquiring
          Person or an associate or affiliate of an Acquiring Person that is not
          a publicly traded entity, each Right will entitle its holder (subject
          to the next paragraph) to purchase, for the Purchase Price, at such
          holder's option, (i) that number of shares of the surviving
          corporation in the transaction with such entity (which surviving
          corporation could be the Company) which at the time of the transaction
          would have a book value of twice the Purchase Price, (ii) that number
          of shares of such entity which at the time of the transaction would
          have a book value of twice the Purchase Price or (iii) if such entity
          has an affiliate which has publicly traded common shares, that number
          of common shares of such affiliate which at the time of the
          transaction would have a market value of twice the Purchase Price.

          Any Rights that are, at any time beneficially owned by an Acquiring
          Person (or any affiliate or associate of an Acquiring Person) will be
          null and void and nontransferable and any holder of any such Right
          (including any purported transferee or subsequent holder) will be
          unable to exercise or transfer any such Right.

          At any time prior to the earlier of (i) the close of business on the
          tenth day following the time the Company learns that a Person has
          become an Acquiring person and (ii) the Expiration Date, the Board of
          Directors of the Company may redeem the Rights in whole, but not in
          part, at a price (in cash or Common Shares or other securities of the
          Company deemed by the Board of Directors to be at least equivalent in
          value) of $.01 per Right, subject to adjustment as provided in the
          Rights Agreement (the "REDEMPTION DATE"); provided, however, that, for
          the 120-day period after any date of a change (resulting from a proxy
          or consent solicitation) in a majority of the Board of Directors of
          the Company in office at the commencement of such solicitation, the
          Rights may only be redeemed if (A) there are directors then in office
          who were in office at the commencement of such solicitation and (B)
          the Board of Directors of the Company, with concurrence of a majority
          of such directors then in office, determines that such redemption is,
          in their judgment, in the best interests of the Company and its
          stockholders.

          Immediately upon the action of the Board of Directors of the Company
          electing to redeem the Rights, and without any further action and
          without any notice, the right to exercise the Rights will terminate
          and the only right of the holders of Rights will be to receive the
          Redemption Price.

          After there is an Acquiring Person, the Board of Directors may elect
          to exchange each Right (other than Rights that shall have become null
          and void and nontransferable as described above) for

                                 Page 4 of 80
<PAGE>
 
          consideration per Right consisting of one-half of the securities that
          would be issuable at such time upon the exercise of one Right pursuant
          to the terms of the Rights Agreement.

          Until a Right is exercised, the holder thereof, as such, will have no
          rights as a stockholder of the company, including, without limitation,
          the right to vote or to receive dividends.

          At any time prior to the Distribution Date, the Company may, without
          the approval of any holder of the Rights, supplement or amend any
          provision of the Rights Agreement (including the date on which the
          Distribution Date shall occur, the time during which the Rights may be
          redeemed or the terms of the Preferred Shares), except that no
          supplement or amendment shall be made which reduces the Redemption
          Price (other than pursuant to certain adjustments therein) or provides
          for an earlier Expiration Date.  Without limiting the foregoing, the
          Company may at any time prior to such time as a person becomes an
          Acquiring Person amend this Agreement to (a) specifically exempt any
          person from being or being deemed to be an Acquiring Person, subject
          to such terms and conditions as the Company deems appropriate, (b) fix
          an Expiration Date later than the date set forth in the Rights
          Agreement or (c) increase the Purchase Price.  However, during the
          120-day period after any date of a change (resulting from a proxy or
          consent solicitation) in a majority of the Board of Directors of the
          Company in office at the commencement of such solicitation, the Rights
          Agreement may be supplemented or amended only if (A) there are
          directors then in office who were in office at the commencement of
          such solicitation and (B) the Board of Directors of the Company, with
          the concurrence of a majority of such directors then in office,
          determines that such supplement or amendment is, in their judgment, in
          the best interests of the Company and its stockholders.

          Preferred Shares purchasable upon exercise of the Rights will not be
          redeemable. Each Preferred Share will be entitled to a minimum
          preferential quarterly dividend payment of $1.00 per share but will be
          entitled to an aggregate dividend of 100 times the dividend declared
          per Common Share. In the event of liquidation, the holders of the
          Preferred Shares will be entitled to a minimum preferential
          liquidation payment of $100 per share but will be entitled to an
          aggregate payment of 100 times the payment made per Common Share. Each
          Preferred Share will have 100 votes, voting together with the Common
          Shares. Finally, in the event of any merger, consolidation or other
          transaction in which Common Shares are exchanged, each Preferred Share
          will be entitled to receive 100 times the amount received per Common
          Share. These rights are protected by customary antidilution
          provisions.

          The Rights have certain antitakeover effects. The Rights will cause
          substantial dilution to a person or group that attempts to acquire the
          Company without conditioning the offer on substantially all the Rights
          being acquired. The Rights will not interfere with any merger or other
          business combination with a third party approved by the Board of
          Directors of the Company since the Board of Directors of the Company
          may, at its option, at any time prior to any person becoming an
          Acquiring Person exempt such Person from being deemed an Acquiring
          Person or redeem all, but not less than all, of the then outstanding
          Rights at the Redemption Price.

          The Rights Agreement specifying the terms of the Rights, the
          Certificate of Designation of the Preferred Shares specifying the
          terms of the Preferred Shares (Exhibit A to the Rights Agreement) and
          the form of Right Certificate (Exhibit B to the Rights

                                 Page 5 of 80
<PAGE>
 
          Agreement) are filed herewith as exhibits. The foregoing description
          of the Rights does not purport to be complete and is qualified in its
          entirety by reference to such exhibits all of which are incorporated
          herein by reference.


Item 2.  Exhibits.

          1. Rights Agreement dated as of May 19, 1995, between Unit
             Corporation and Chemical Bank, as Rights Agent.

          2. Form of Certificate of the Voting Powers, Preferences and
             Relative, Participating, Optional and other Special Rights,
             Qualifications, Limitations or Restrictions of Series A
             Participating Cumulative Preferred Stock of Unit Corporation
             (which is attached as Exhibit A to the Rights Agreement filed as
             Exhibit 1 hereto).

          3. Form of Rights Certificate (which is attached as Exhibit B to
             the Rights Agreement filed as Exhibit 1 hereto).

 
          4. Form of Summary of Rights to Purchase Preferred Stock (which is
             attached as Exhibit C to the Rights Agreement filed as Exhibit 1
             hereto).

                                   SIGNATURES

     Pursuant to the requirements of Section 12 of the Securities Exchange Act
of 1934, the registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, thereunto duly authorized.



                                               UNIT CORPORATION



                                               by   /s/ John G. Nikkel
Dated: May 23, 1995                            -----------------------
                                               Name:  John G. Nikkel
                                               Title: President

                                 Page 6 of 80
<PAGE>
 
                               INDEX OF EXHIBITS

<TABLE>
<CAPTION>
                                                               Page Number
                                                                   is
                                                              Sequentially
Exhibit                                                         Numbered
Number                      Title                               Statement
<C>              <S>                                           <C> 
 1               Rights Agreement dated as of
                 May 19, 1995, between Unit
                 Corporation and Chemical Bank,
                 as Rights Agent                                   8

 1(A)            Form of Certificate of the Voting
                 Powers, Preferences and Relative,
                 Participating, Optional and other
                 Special Rights, Qualifications,
                 Limitations or Restrictions of
                 Series A Participating Cumulative
                 Preferred Stock of Unit Corporation              57
                 
 1(B)            Form of Right Certificate                        67

 1(C)            Form of Summary of Rights to Purchase
                 Preferred Stock                                  74
</TABLE> 

                                 Page 7 of 80

<PAGE>
 
                                                                       EXHIBIT 1

                               RIGHTS AGREEMENT


                           Dated as of May 19, 1995


                                    between


                               UNIT CORPORATION


                                      and


                                 Chemical Bank


                                as Rights Agent

                                 Page 8 of 80
<PAGE>
 
                               Table of Contents

<TABLE>
<CAPTION>
Section                                                           Page
-------                                                           ----
<S>       <C>                                                     <C>
 1.       Certain Definitions................................      11

 2.       Appointment of Rights Agent........................      21

 3.       Issue of Rights and Right Certificates.............      21

 4.       Form of Right Certificates.........................      23

 5.       Execution, Countersignature and Registration.......      24

 6.       Transfer, Split-Up, Combination and Exchange
             of Right Certificates; Mutilated, Destroyed,
             Lost or Stolen Right Certificates;
             Uncertificated Rights...........................      25

 7.       Exercise of Rights; Expiration Date of Rights......      26

 8.       Cancellation and Destruction of Right
             Certificates....................................      29

 9.       Reservation and Availability of Preferred Shares...      29
 
10.       Preferred Shares Record Date.......................      31

11.       Adjustments in Rights After There Is an
             Acquiring Person; Exchange of Rights for
             Shares; Business Combinations...................      32
 
12.       Certain Adjustments................................      38
 
13.       Certificate of Adjustment..........................      40
 
14.       Additional Covenants...............................      40
 
15.       Fractional Rights and Fractional Shares............      41
 
16.       Rights of Action...................................      42

17.       Transfer and Ownership of Rights and
             Right Certificates..............................      43

18.       Right Certificate Holder Not Deemed a
             Stockholder.....................................      43
 
19.       Concerning the Rights Agent........................      44
 
20.       Merger or Consolidation or Change of Rights Agent..      44
 
21.       Duties of Rights Agent.............................      45
 
22.       Change of Rights Agent.............................      49
</TABLE> 

                                 Page 9 of 80
<PAGE>
 
<TABLE> 

<S>       <C>                                                     <C>
23.       Issuance of Additional Rights and Right
             Certificates....................................      50
 
24.       Redemption and Termination.........................      51
 
25.       Notices............................................      52
 
26.       Supplements and Amendments.........................      53
 
27.       Successors.........................................      54

28.       Benefits of Rights Agreement;
             Determinations and Actions by
             the Board of Directors, etc.....................      54
 
29.       Severability.......................................      55
 
30.       Governing Law......................................      55
 
31.       Counterparts; Effectiveness........................      55
 
32.       Descriptive Headings...............................      55
 
Exhibits

          A    Certificate of Designation....................      57

          B    Form of Right Certificate.....................      67

          C    Summary of Rights to Purchase
                   Preferred Stock...........................      74
</TABLE> 

                                 Page 10 of 80
<PAGE>
 
          RIGHTS AGREEMENT dated as of May 19, 1995, between
          Unit Corporation, a Delaware corporation (the
          "Company"), and Chemical Bank, a New York banking
          corporation, as Rights Agent (the "Rights Agent").


          The Board of Directors of the Company has authorized and declared a
dividend of one Right (as hereinafter defined) for each share of Common Stock,
par value $0.20 per share, of the Company (the "Common Stock") outstanding at
the Close of Business (as hereinafter defined) on May 31, 1995 (the "Record
Date"), and has authorized the issuance of one Right (as such number may
hereafter be adjusted pursuant to the provisions of this Rights Agreement) with
respect to each share of Common Stock that shall become outstanding between the
Record Date and the earliest of the Distribution Date, the Redemption Date or
the Expiration Date (as such terms are hereinafter defined); provided, however,
that Rights may be issued with respect to shares of Common Stock that shall
become outstanding after the Distribution Date and prior to the earlier of the
Redemption Date or the Expiration Date in accordance with the provisions of
Section 23.  Each Right shall initially represent the right to purchase one one
hundredth (1/100th) of a share of Series A Participating Cumulative Preferred
Stock, par value $1.00 per share, of the Company (the "Preferred Shares"),
having the powers, rights and preferences set forth in the Certificate of
Designation attached as Exhibit A.

          Accordingly, in consideration of the premises and the mutual
agreements herein set forth, the parties hereby agree as follows:

          SECTION 1.  CERTAIN DEFINITIONS.   For purposes of this Rights
Agreement, the following terms have the meanings indicated:

          "Acquiring Person" shall mean any Person who or which, alone or
together with all Affiliates and Associates of such Person, shall be the
Beneficial Owner of more than 15% of the Common Shares then outstanding, but
shall not include (a) the Company, any Subsidiary of the Company, any employee
benefit plan of the Company or of any of its Subsidiaries, or any Person

                                 Page 11 of 80
<PAGE>
 
holding Common Shares for or pursuant to the terms of any such employee benefit
plan or (b) any such Person who has become such a Beneficial Owner solely
because (i) of a change in the aggregate number of Common Shares outstanding
since the last date on which such Person acquired Beneficial Ownership of any
Common Shares or (ii) it acquired such Beneficial Ownership in the good faith
belief that such acquisition would not (x) cause such Beneficial Ownership to
exceed 15% of the Common Shares then outstanding and such Person relied in good
faith in computing the percentage of its Beneficial Ownership on publicly filed
reports or documents of the Company which are inaccurate or out-of-date or (y)
otherwise cause a Distribution Date or the adjustment provided for in Section
11(a) to occur. Notwithstanding clause (b) of the prior sentence, if any Person
that is not an Acquiring Person due to such clause (b) does not reduce its
percentage of Beneficial Ownership of Common Shares to 15% or less by the Close
of Business on the fifth Business Day after notice from the Company (the date of
notice being the first day) that such Person's Beneficial Ownership of Common
Shares so exceeds 15%, such Person shall, at the end of such five Business Day
period, become an Acquiring Person (and such clause (b) shall no longer apply to
such Person). For purposes of this definition, the determination whether any
Person acted in "good faith" shall be conclusively determined by the Board of
Directors of the Company, acting by a vote of those directors of the Company
whose approval would be required to redeem the Rights under Section 24.

          "Affiliate" and "Associate", when used with reference to any Person,
shall have the respective meanings ascribed to such terms in Rule 12b-2 of the
General Rules and Regulations under the Exchange Act, as in effect on the date
of this Rights Agreement.

          A Person shall be deemed the "Beneficial Owner" of, and shall be
deemed to "beneficially own", and shall be deemed to have "Beneficial Ownership"
of, any securities:

          (i) which such Person or any of such Person's Affiliates or Associates
     is deemed to "beneficially own" within the meaning of Rule

                                 Page 12 of 80
<PAGE>
 
     13d-3 of the General Rules and Regulations under the Exchange Act, as in
     effect on the date of this Rights Agreement;

          (ii) which such Person or any of such Person's Affiliates or
     Associates has (A) the right to acquire (whether such right is exercisable
     immediately or only after the passage of time) pursuant to any agreement,
     arrangement or understanding (written or oral), or upon the exercise of
     conversion rights, exchange rights, rights (other than the Rights),
     warrants or options, or otherwise; provided, however, that a Person shall
     not be deemed the Beneficial Owner of, or to beneficially own, or to have
     Beneficial Ownership of, securities tendered pursuant to a tender or
     exchange offer made by or on behalf of such Person or any of such Person's
     Affiliates or Associates until such tendered securities are accepted for
     purchase or exchange thereunder, or (B) the right to vote pursuant to any
     agreement, arrangement or understanding (written or oral); provided,
     however, that a Person shall not be deemed the Beneficial Owner of, or to
     beneficially own, any security if (1) the agreement, arrangement or
     understanding (written or oral) to vote such security arises solely from a
     revocable proxy or consent given to such Person in response to a public
     proxy or consent solicitation made pursuant to, and in accordance with, the
     applicable rules and regulations under the Exchange Act and (2) the
     beneficial ownership of such security is not also then reportable on
     Schedule 13D under the Exchange Act (or any comparable or successor
     report);

          (iii) which are beneficially owned, directly or indirectly, by any
     other Person with which such Person or any of such Person's Affiliates or
     Associates has any agreement, arrangement or understanding (written or
     oral) for the purpose of acquiring, holding, voting (except pursuant to a
     revocable proxy as described in clause (ii)(B) of this definition) or
     disposing of any securities of the Company.

Notwithstanding the foregoing, nothing contained in this definition shall cause
a Person ordinarily engaged in business as an underwriter of securities

                                 Page 13 of 80
<PAGE>
 
to be the "Beneficial Owner" of, or to "beneficially own", any securities
acquired in a bona fide firm commitment underwriting pursuant to an underwriting
agreement with the Company.

          Notwithstanding the foregoing, none of the Company's directors,
officers or financial advisers shall be deemed to be the Beneficial Owner of, or
to beneficially own or be deemed to have Beneficial Ownership of, any Common
Shares of the Company owned by any other director, officer or financial adviser
of the Company by virtue of such persons acting in their capacities as such,
including, without limitation, in connection with any formulation and
publication of the Board of Director's recommendation of a position, and any
actions taken in furtherance thereof, with respect to any acquisition proposal
relating to the Company, any tender or exchange offer for the Common Shares of
the Company, or any solicitation of proxies with respect to the Common Shares of
the Company.

          "Book Value", when used with reference to Common Shares issued by any
Person, shall mean the amount of equity of such Person applicable to each Common
Share, determined (i) in accordance with generally accepted accounting
principles in effect on the date as of which such Book Value is to be
determined,  (ii) using all the consolidated assets and all the consolidated
liabilities of such Person on the date as of which such Book Value is to be
determined, except that no value shall be included in such assets for goodwill
arising from consummation of a business combination, and (iii) after giving
effect to (A) the exercise of all rights, options and warrants to purchase such
Common Shares (other than the Rights), and the conversion of all securities
convertible into such Common Shares, at an exercise or conversion price, per
Common Share, which is less than such Book Value before giving effect to such
exercise or conversion (whether or not exercisability or convertibility is
conditioned upon occurrence of a future event), (B) all dividends and other
distributions on the capital stock of such Person declared prior to the date as
of which such Book Value is to be determined and to be paid or made after such
date, and (C) any other agreement, arrangement or understanding (written or
oral), or transaction or other action prior to the

                                 Page 14 of 80
<PAGE>
 
date as of which such Book Value is to be determined which would have the effect
of thereafter reducing such Book Value.

          "Business Combination" shall have the meaning set forth in Section
11(c)(I).

          "Business Day" shall mean each Monday, Tuesday, Wednesday, Thursday
and Friday which is not a day on which banking institutions in the Borough of
Manhattan, The City of New York, are authorized or obligated by law or executive
order to close.

          "Certificate of Designation" shall mean the Certificate of Designation
of Series A Participating Cumulative Preferred Stock setting forth the powers,
preferences, rights, qualifications, limitations and restrictions of such series
of Preferred Stock of the Company, a copy of which is attached as Exhibit A.

          "Close of Business" on any given date shall mean 5:00 p.m., New York
City time, on such date; provided, however, that, if such date is not a Business
Day, "Close of Business" shall mean 5:00 p.m., New York City time, on the next
succeeding Business Day.

          "Common Shares", when used with reference to the Company prior to a
Business Combination, shall mean the shares of Common Stock of the Company or
any other shares of capital stock of the Company into which the Common Stock
shall be reclassified or changed.  "Common Shares", when used with reference to
any Person (other than the Company prior to a Business Combination), shall mean
shares of capital stock of such Person (if such Person is a corporation) of any
class or series, or units of equity interests in such Person (if such Person is
not a corporation) of any class or series, the terms of which do not limit (as a
maximum amount and not merely in proportional terms) the amount of dividends or
income payable or distributable on such class or series or the amount of assets
distributable on such class or

                                 Page 15 of 80
<PAGE>
 
series upon any voluntary or involuntary liquidation, dissolution or winding up
of such Person and do not provide that such class or series is subject to
redemption at the option of such Person, or any shares of capital stock or units
of equity interests into which the foregoing shall be reclassified or changed;
provided, however, that, if at any time there shall be more than one such class
or series of capital stock or equity interests of such Person, "Common Shares"
of such Person shall include all such classes and series substantially in the
proportion of the total number of shares or other units of each such class or
series outstanding at such time.

          "Common Stock" shall have the meaning set forth in the introductory
paragraph of this Rights Agreement.

          "Company" shall have the meaning set forth in the heading of this
Rights Agreement; provided, however, that if there is a Business Combination,
"Company" shall have the meaning set forth in Section 11(c)(III).

          The term "control" with respect to any Person shall mean the power to
direct the management and policies of such Person, directly or indirectly, by or
through stock ownership, agency or otherwise, or pursuant to or in connection
with an agreement, arrangement or understanding (written or oral) with one or
more other Persons by or through stock ownership, agency or otherwise; and the
terms "controlling" and "controlled" shall have meanings correlative to the
foregoing.

          "Distribution Date" shall have the meaning set forth in Section 3(b).

          "Exchange Act" shall mean the Securities Exchange Act of 1934, as in
effect on the date in question, unless otherwise specifically provided.

          "Exchange Consideration" shall have the meaning set forth in Section
11(b)(I).

                                 Page 16 of 80
<PAGE>
 
          "Expiration Date" shall have the meaning set forth in Section 7(a).

          "Major Part", when used with reference to the assets of the Company
and its Subsidiaries as of any date, shall mean assets (i) having a fair market
value aggregating 50% or more of the total fair market value of all the assets
of the Company and its Subsidiaries (taken as a whole) as of the date in
question,  (ii) accounting for 50% or more of the total value (net of
depreciation and amortization) of all the assets of the Company and its
Subsidiaries (taken as whole) as would be shown on a consolidated or combined
balance sheet of the Company and its Subsidiaries as of the date in question,
prepared in accordance with generally accepted accounting principles then in
effect, or (iii) accounting for 50% or more of the total amount of earnings
before interest, taxes, depreciation and amortization or revenues of the Company
and its Subsidiaries (taken as a whole) as would be shown on, or derived from, a
consolidated or combined statement of income of the Company and its Subsidiaries
for the period of 12 months ending on the last day of the Company's monthly
accounting period next preceding the date in question, prepared in accordance
with generally accepted accounting principles then in effect.

          "Market Value", when used with reference to Common Shares on any date,
shall be deemed to be the average of the daily closing prices, per share, of
such Common Shares for the period which is the shorter of (1) 30 consecutive
Trading Days immediately prior to the date in question or (2) the number of
consecutive Trading Days beginning on the Trading Day immediately after the date
of the first public announcement of the event requiring a determination of the
Market Value and ending on the Trading Day immediately prior to the record date
of such event; provided, however, that, in the event that the Market Value of
such Common Shares is to be determined in whole or in part during a period
following the announcement by the issuer of such Common Shares of any action of
the type described in Section 12(a) that would require an adjustment thereunder,
then, and in each such case, the Market Value of such Common Shares shall be
appropriately adjusted to reflect the effect of

                                 Page 17 of 80
<PAGE>
 
such action on the market price of such Common Shares. The closing price for
each Trading Day shall be the closing price quoted on the composite tape for
securities listed on the New York Stock Exchange, or, if such securities are not
quoted on such composite tape or if such securities are not listed on such
exchange, on the principal United States securities exchange registered under
the Exchange Act (or any recognized foreign stock exchange) on which such
securities are listed, or, if such securities are not listed on any such
exchange, the average of the closing bid and asked quotations with respect to a
share of such securities on the National Association of Securities Dealers, Inc.
Automated Quotations System ("NASDAQ") or such other system then in use, or if
no such quotations are available, the average of the closing bid and asked
prices as furnished by a professional market maker making a market in such
securities selected by the Board of Directors of the Company. If on any such
Trading Day no market maker is making a market in such securities, the closing
price of such securities on such Trading Day shall be deemed to be the fair
value of such securities as determined in good faith by the Board of Directors
of the Company (whose determination shall be described in a statement filed with
the Rights Agent and shall be binding on the Rights Agent, the holders of Rights
and all other Persons); provided, however, that for the purpose of determining
the closing price of the Preferred Shares for any Trading Day on which there is
no such market maker for the Preferred Shares the closing price on such Trading
Day shall be deemed to be the Formula Number (as defined in the Certificate of
Designation) times the closing price of the Common Shares of the Company on such
Trading Day.

          "Person" shall mean an individual, corporation, partnership, joint
venture, association, trust, unincorporated organization or other entity.

          "Preferred Shares" shall have the meaning set forth in the
introductory paragraph of this Rights Agreement.  Any reference in this Rights
Agreement to Preferred Shares shall be deemed to include any authorized fraction
of a Preferred Share, unless the context otherwise requires.

                                 Page 18 of 80
<PAGE>
 
          "Principal Party" shall mean the Surviving Person in a Business
Combination; provided, however, that, if such Surviving Person is a direct or
indirect Subsidiary of any other Person, "Principal Party" shall mean the Person
which is the ultimate parent of such Surviving Person and which is not itself a
Subsidiary of another Person.  In the event ultimate control of such Surviving
Person is shared by two or more Persons, "Principal Party" shall mean that
Person that is immediately controlled by such two or more Persons.

          "Purchase Price" with respect to each Right shall mean $12.75, as such
amount may from time to time be adjusted as provided herein, and shall be
payable in lawful money of the United States of America.  All references herein
to the Purchase Price shall mean the Purchase Price as in effect at the time in
question.

          "Record Date" shall have the meaning set forth in the introductory
paragraph of this Rights Agreement.

          "Redemption Date" shall have the meaning set forth in Section 24(a).

          "Redemption Price" with respect to each Right shall mean $.01, as such
amount may from time to time be adjusted in accordance with Section 12.  All
references herein to the Redemption Price shall mean the Redemption Price as in
effect at the time in question.

          "Registered Common Shares" shall mean Common Shares which are, as of
the date of consummation of a Business Combination, and have continuously been
for the 12 months immediately preceding such date, registered under Section 12
of the Exchange Act.

          "Right Certificate" shall mean a certificate evidencing a Right in
substantially the form attached as Exhibit B.

                                 Page 19 of 80
<PAGE>
 
          "Rights" shall mean the rights to purchase Preferred Shares (or other
securities) as provided in this Rights Agreement.

          "Securities Act" shall mean the Securities Act of 1933, as in effect
on the date in question, unless otherwise specifically provided.

          "Subsidiary" shall mean a Person, at least a majority of the total
outstanding voting power (being the power under ordinary circumstances (and not
merely upon the happening of a contingency) to vote in the election of directors
of such Person (if such Person is a corporation) or to participate in the
management and control of such Person (if such Person is not a corporation)) of
which is owned, directly or indirectly, by another Person or by one or more
other Subsidiaries of such other Person or by such other Person and one or more
other Subsidiaries of such other Person.

          "Surviving Person" shall mean (1) the Person which is the continuing
or surviving Person in a consolidation or merger specified in Section
11(c)(I)(i) or 11(c)(I)(ii) or (2) the Person to which the Major Part of the
assets of the Company and its Subsidiaries is sold, leased, exchanged or
otherwise transferred or disposed of in a transaction specified in Section
11(c)(I)(iii) provided, however, that, if the Major Part of the assets of the
Company and its Subsidiaries is sold, leased, exchanged or otherwise transferred
or disposed of in one or more related transactions specified in Section
11(c)(I)(iii) to more than one Person, the "Surviving Person" in such case shall
mean the Person that acquired assets of the Company and/or its Subsidiaries with
the greatest fair market value in such transaction or transactions.

          "Trading Day" shall mean a day on which the principal national
securities exchange (or principal recognized foreign stock exchange, as the case
may be) on which any securities or Rights, as the case may be, are listed or
admitted to trading is open for the transaction of business or, if the
securities or Rights in question are not listed or admitted to trading on any

                                 Page 20 of 80
<PAGE>
 
national securities exchange (or recognized foreign stock exchange, as the case
may be), a Business Day.

          SECTION 2.  APPOINTMENT OF RIGHTS AGENT.  The Company hereby appoints
the Rights Agent to act as agent for the Company in accordance with the terms
and conditions hereof, and the Rights Agent hereby accepts such appointment.
The Company may from time to time appoint one or more co-Riqhts Agents as it may
deem necessary or desirable (the term "Rights Agent" being used herein to refer,
collectively, to the Rights Agent together with any such co-Rights Agents).  In
the event the Company appoints one or more co-Rights Agents, the respective
duties of the Rights Agent and any co-Rights Agents shall be as the Company
shall determine.

          SECTION 3.  ISSUE OF RIGHTS AND RIGHT CERTIFICATES.  (a) One Right
shall be associated with each Common Share outstanding on the Record Date, each
additional Common Share that shall become outstanding between the Record Date
and the earliest of the Distribution Date, the Redemption Date or the Expiration
Date and each additional Common Share with which Rights are issued after the
Distribution Date but prior to the earlier of the Redemption Date or the
Expiration Date as provided in Section 23; provided, however, that, if the
number of outstanding Rights are combined into a smaller number of outstanding
Rights pursuant to Section 12(a), the appropriate fractional Right determined
pursuant to such Section shall thereafter be associated with each such Common
Share.

          (b) Until the earlier of (i) the tenth day after the Company learns
that a Person has become an Acquiring Person or (ii) the tenth Business Day (or
such later date as may be determined by action of the Board of Directors of the
Company prior to such time as any Person becomes an Acquiring Person) following
the date of the commencement of, or first public disclosure of an intent to
commence, a tender or exchange offer by any Person (other than the Company, any
Subsidiary of the Company, any employee benefit plan of the Company or of any of
its Subsidiaries, or any Person holding Common Shares for or pursuant to the
terms of any such employee benefit plan) for outstanding

                                 Page 21 of 80
<PAGE>
 
Common Shares, if upon consummation of such tender or exchange offer such Person
could be the Beneficial Owner of more than 15% of the outstanding Common Shares
(the Close of Business on the earlier of such dates being the "Distribution
Date"), (x) the Rights will be evidenced by the certificates for Common Shares
registered in the names of the holders thereof and not by separate Right
Certificates and (y) the Rights, including the right to receive Right
Certificates, will be transferable only in connection with the transfer of
Common Shares. As soon as practicable after the Distribution Date, the Rights
Agent will send, by first-class, postage-prepaid mail, to each record holder of
Common Shares as of the Distribution Date, at the address of such holder shown
on the records of the Company, a Right Certificate evidencing one whole Right
for each Common Share (or for the number of Common Shares with which one whole
Right is then associated if the number of Rights per Common Share held by such
record holder has been adjusted in accordance with the proviso in Section 3(a)).
If the number of Rights associated with each Common Share has been adjusted in
accordance with the proviso in Section 3(a), at the time of distribution of the
Right Certificates the Company may make any necessary and appropriate rounding
adjustments so that Right Certificates representing only whole numbers of Rights
are distributed and cash is paid in lieu of any fractional Right in accordance
with Section 15(a). As of and after the Distribution Date, the Rights will be
evidenced solely by such Right Certificates.

          (c) On the Record Date, or as soon as practicable thereafter, the
Company will send a copy of a Summary of Rights to Purchase Preferred Shares, in
substantially the form of Exhibit C hereto (the "Summary of Rights"), by first-
class, postage-prepaid mail, to each record holder of Common Shares as of the
Close of Business on the Record Date, at the address of such holder shown on the
records of the Company.  With respect to any certificate for Common Shares,
until the earliest of the Distribution Date, the Redemption Date or the
Expiration Date, the Rights associated with the Common Shares represented by any
such certificate shall be evidenced by such certificate alone, the registered
holders of the Common Shares shall also be the registered holders of the
associated Rights and the surrender for transfer of

                                 Page 22 of 80
<PAGE>
 
any such certificate shall also constitute the transfer of the Rights associated
with the Common Shares represented thereby.

          (d) Certificates issued for Common Shares after the Record Date
(including, without limitation, upon transfer or exchange of outstanding Common
Shares), but prior to the earliest of the Distribution Date, the Redemption Date
or the Expiration Date, may have printed on, written on or otherwise affixed to
them the following legend:

          This certificate also evidences and entitles the holder hereof to
     certain Rights as set forth in a Rights Agreement dated as of May 19, 1995,
     as it may be amended from time to time (the "Rights Agreement"), between
     Unit Corporation (the "Company") and Chemical Bank, as Rights Agent (the
     "Rights Agent"), the terms of which are hereby incorporated herein by
     reference and a copy of which is on file at the principal executive offices
     of the Company.  Under certain circumstances, as set forth in the Rights
     Agreement, such Rights will be evidenced by separate certificates and will
     no longer be evidenced by this certificate.  The Rights Agent will mail to
     the holder of this certificate a copy of the Rights Agreement without
     charge after receipt of a written request therefor.  Rights beneficially
     owned by Acquiring Persons or their Affiliates or Associates (as such terms
     are defined in the Rights Agreement) and by any subsequent holder of such
     Rights are null and void and nontransferable.

Notwithstanding this paragraph (d), the omission of a legend shall not affect
the enforceability of any part of this Rights Agreement or the rights of any
holder of Rights.

     SECTION 4.  FORM OF RIGHT CERTIFICATES.  The Right Certificates (and the
form of election to purchase and form of assignment to be printed on the reverse
side thereof) shall be in substantially the form set forth as Exhibit B and may
have such marks of identification or designation and such legends, summaries or
endorsements printed thereon as the Company may deem appropriate

                                 Page 23 of 80
<PAGE>
 
and as are not inconsistent with the provisions of this Rights Agreement, or as
may be required to comply with any applicable law or with any rule or regulation
made pursuant thereto or with any rule or regulation of any stock exchange on
which the Rights may from time to time be listed, or to conform to usage.
Subject to the provisions of Sections 7, 11 and 23, the Right Certificates,
whenever issued, shall be dated as of the Distribution Date, and on their face
shall entitle the holders thereof to purchase such number of Preferred Shares as
shall be set forth therein for the Purchase Price set forth therein, subject to
adjustment from time to time as herein provided.

     SECTION 5.  EXECUTION, COUNTERSIGNATURE AND REGISTRATION.  (a) The Right
Certificates shall be executed on behalf of the Company by the Chairman of the
Board, the Chief Executive Officer, the President, the Chief Operating Officer,
the Treasurer or a Vice President (whether preceded by any additional title) of
the Company, either manually or by facsimile signature, and have affixed thereto
the Company's seal or a facsimile thereof which shall be attested by the
Secretary, an Assistant Secretary or a Vice President (whether preceded by any
additional title, provided that such Vice President shall not have also executed
the Right Certificates) of the Company, either manually or by facsimile
signature.  The Right Certificates shall be manually countersigned by the Rights
Agent and shall not be valid or obligatory for any purpose unless so
countersigned.  In case any officer of the Company who shall have signed any of
the Right Certificates shall cease to be such an officer of the Company before
countersignature by the Rights Agent and issuance and delivery by the Company,
such Right Certificates may nevertheless be countersigned by the Rights Agent
and issued and delivered by the Company with the same force and effect as though
the person who signed such Right Certificates had not ceased to be such an
officer of the Company; and any Right Certificate may be signed on behalf of the
Company by any person who, at the actual date of execution of such Right
Certificate, shall be a proper officer of the Company to sign such Right
Certificate, although at the date of execution of this Rights Agreement any such
person was not such an officer of the Company.

                                 Page 24 of 80
<PAGE>
 
          (b) Following the Distribution Date, the Rights Agent will keep or
cause to be kept, at its principal office in New York, New York, books for
registration and transfer of the Right Certificates issued hereunder.  Such
books shall show the names and addresses of the respective holders of the Right
Certificates, the number of Rights evidenced by each of the Right Certificates,
the certificate number of each of the Right Certificates and the date of each of
the Right Certificates.

          SECTION 6.  TRANSFER, SPLIT-UP, COMBINATION AND EXCHANGE OF RIGHT
CERTIFICATES; MUTILATED, DESTROYED, LOST OR STOLEN RIGHT CERTIFICATES;
UNCERTIFICATED RIGHTS.  (a) Subject to the provisions of Sections 7(e) and 15,
at any time after the Distribution Date, and at or prior to the Close of
Business on the earlier of the Redemption Date or the Expiration Date, any Right
Certificate or Right Certificates may be transferred, split-up, combined or
exchanged for another Right Certificate or Right Certificates representing, in
the aggregate, the same number of Rights as the Right Certificate or Right
Certificates surrendered then represented.  Any registered holder desiring to
transfer, split-up, combine or exchange any Right Certificate shall make such
request in writing delivered to the Rights Agent and shall surrender the Right
Certificate or Right Certificates to be transferred, splitup, combined or
exchanged at the principal office of the Rights Agent; provided, however, that
neither the Rights Agent nor the Company shall be obligated to take any action
whatsoever with respect to the transfer of any Right Certificate surrendered for
transfer until the registered holder shall have completed and signed the
certification contained in the form of assignment on the reverse side of such
Right Certificate and shall have provided such additional evidence of the
identity of the Beneficial Owner (or former Beneficial Owner) or Affiliates or
Associates thereof as the Company shall reasonably request.  Thereupon the
Rights Agent shall, subject to Sections 7(e) and 15, countersign and deliver to
the Person entitled thereto a Right Certificate or Right Certificates, as the
case may be, as so requested.  The Company may require payment of a sum
sufficient to cover any tax or governmental charge that may be imposed in
connection with any transfer, split-up, combination or exchange of Right
Certificates.

                                 Page 25 of 80
<PAGE>
 
          (b) Upon receipt by the Company and the Rights Agent of evidence
reasonably satisfactory to them of the loss, theft, destruction or mutilation of
a valid Right Certificate, and, in case of loss, theft or destruction, of
indemnity or security reasonably satisfactory to them, and, at the Company's
request, reimbursement to the Company and the Rights Agent of all reasonable
expenses incidental thereto, and upon surrender to the Rights Agent and
cancellation of the Right Certificate if mutilated, the Company will make a new
Right Certificate of like tenor and deliver such new Right Certificate to the
Rights Agent for delivery to the registered owner in lieu of the Right
Certificate so lost, stolen, destroyed or mutilated.

          (c) Notwithstanding any other provision hereof, the Company and the
Rights Agent may amend this Rights Agreement to provide for uncertificated
Rights in addition to or in place of Rights evidenced by Right Certificates.

          SECTION 7.  EXERCISE OF RIGHTS; EXPIRATION DATE OF RIGHTS.  (a)
Subject to Section 7(e) and except as otherwise provided herein (including
Section 11), each Right shall entitle the registered holder thereof, upon
exercise thereof as provided herein, to purchase for the Purchase Price, at any
time after the Distribution Date and at or prior to the earlier of (i) the Close
of Business on the 10th anniversary of the date of this Rights Agreement (the
Close of Business on such date being the "Expiration Date"), (ii) the Redemption
Date, or (iii) the time at which such Rights are exchanged as provided in
Section 11, one one-hundredth (1/100th) of a Preferred Share, subject to
adjustment from time to time as provided in Sections 11 and 12.

          (b) The registered holder of any Right Certificate may exercise the
Rights evidenced thereby (except as otherwise provided herein) in whole or in
part at any time after the Distribution Date, upon surrender of the Right
Certificate, with the form of election to purchase on the reverse side thereof
duly executed, to the Rights Agent at the principal office of the Rights Agent
in New York, New York, together with payment of the Purchase Price for each one
one-hundredth (1/100th) of a Preferred Share as to which the Rights are

                                 Page 26 of 80
<PAGE>
 
exercised, at or prior to the earlier of (i) the Expiration Date or (ii) the
Redemption Date.

          (c) Upon receipt of a Right Certificate representing exercisable
Rights, with the form of election to purchase duly executed, accompanied by
payment of the Purchase Price for the Preferred Shares to be purchased together
with an amount equal to any applicable transfer tax, in lawful money of the
United States of America, in cash or by certified check or money order payable
to the order of the Company, the Rights Agent shall thereupon (i) either (A)
promptly requisition from any transfer agent of the Preferred Shares (or make
available, if the Rights Agent is the transfer agent) certificates for the
number of Preferred Shares to be purchased and the Company hereby irrevocably
authorizes its transfer agent to comply with all such requests or (B) if the
Company shall have elected to deposit the Preferred Shares with a depositary
agent under a depositary arrangement, promptly requisition from the depositary
agent depositary receipts representing the number of one one-hundredth (1/100th)
of a Preferred Share to be purchased (in which case certificates for the
Preferred Shares to be represented by such receipts shall be deposited by the
transfer agent with the depositary agent) and the Company will direct the
depositary agent to comply with all such requests,  (ii) when appropriate,
promptly requisition from the Company the amount of cash to be paid in lieu of
issuance of fractional shares in accordance with Section 15, (iii) promptly
after receipt of such certificates or depositary receipts, cause the same to be
delivered to or upon the order of the registered holder of such Right
Certificate, registered in such name or names as may be designated by such
holder and (iv) when appropriate, after receipt promptly deliver such cash to or
upon the order of the registered holder of such Right Certificate.

          (d) In case the registered holder of any Right Certificate shall
exercise fewer than all the Rights evidenced thereby, a new Right Certificate
evidencing Rights equivalent to the Rights remaining unexercised shall be issued
by the Rights Agent and delivered to the registered holder of such

                                 Page 27 of 80
<PAGE>
 
Right Certificate or to his duly authorized assigns, subject to the provisions
of Section 15.

          (e) Notwithstanding anything in this Rights Agreement to the contrary,
any Rights that are at any time beneficially owned by an Acquiring Person or any
Affiliate or Associate of an Acquiring Person shall be null and void and
nontransferable, and any holder of any such Right (including any purported
transferee or subsequent holder) shall not have any right to exercise or
transfer any such Right.

          (f) Notwithstanding anything in this Rights Agreement to the contrary,
neither the Rights Agent nor the Company shall be obligated to undertake any
action with respect to a registered holder of any Right Certificates upon the
occurrence of any purported exercise as set forth in this Section 7 unless such
registered holder shall have (i) completed and signed the certificate contained
in the form of election to purchase set forth on the reverse side of the Right
Certificate surrendered for such exercise and (ii) provided such additional
evidence of the identity of the Beneficial Owner (or former Beneficial Owner) or
Affiliates or Associates thereof as the Company shall reasonably request.

          (g) The Company may temporarily suspend, for a period of time not to
exceed 90 calendar days after the Distribution Date, the exercisability of the
Rights in order to prepare and file a registration statement under the
Securities Act, on appropriate form, with respect to the Preferred Shares
purchasable upon exercise of the Rights and permit such registration statement
to become effective; provided, however, that no such suspension shall remain
effective after, and the Rights shall without any further action by the Company
or any other Person become exercisable immediately upon, the effectiveness of
such registration statement.  Upon any such suspension, the Company shall issue
a public announcement stating that the exercisability of the Rights has been
temporarily suspended and shall issue a further public announcement at such time
as the suspension is no longer in effect.  Notwithstanding any provision herein
to the contrary, the Rights shall not be

                                 Page 28 of 80
<PAGE>
 
exercisable in any jurisdiction if the requisite qualification under the blue
sky or securities laws of such jurisdiction shall not have been obtained or the
exercise of the Rights shall not be permitted under applicable law.

          SECTION 8.  CANCELLATION AND DESTRUCTION OF RIGHT CERTIFICATES.  All
Right Certificates surrendered or presented for the purpose of exercise,
transfer, split-up, combination or exchange shall, and any Right Certificate
representing Rights that have become null and void and nontransferable pursuant
to Section 7(e) surrendered or presented for any purpose shall, if surrendered
or presented to the Company or to any of its agents, be delivered to the Rights
Agent for cancellation or in canceled form, or, if surrendered or presented to
the Rights Agent, shall be canceled by it, and no Right Certificates shall be
issued in lieu thereof except as expressly permitted by this Rights Agreement.
The Company shall deliver to the Rights Agent for cancellation and retirement,
and the Rights Agent shall so cancel and retire, any Right Certificate purchased
or acquired by the Company.  The Rights Agent shall deliver all canceled Right
Certificates to the Company, or shall, at the written request of the Company,
destroy such canceled Right Certificates, and in such case shall deliver a
certificate of destruction thereof to the Company.

          SECTION 9.  RESERVATION AND AVAILABILITY OF PREFERRED SHARES.  (a)
The Company covenants and agrees that it will cause to be reserved and kept
available out of its authorized and unissued Preferred Shares or any authorized
and issued Preferred Shares held in its treasury, free from preemptive rights or
any right of first refusal, a number of Preferred Shares sufficient to permit
the exercise in full of all outstanding Rights.

          (b)  In the event that there shall not be sufficient Preferred Shares
issued but not outstanding or authorized but unissued to permit the exercise or
exchange of Rights in accordance with Section 11, the Company covenants and
agrees that it will take all such action as may be necessary to authorize
additional Preferred Shares for issuance upon the exercise or exchange of Rights
pursuant to Section 11; provided, however, that if the

                                 Page 29 of 80
<PAGE>
 
Company is unable to cause the authorization of additional Preferred Shares,
then the Company shall, or in lieu of seeking any such authorization, the
Company may, to the extent necessary and permitted by applicable law and any
agreements or instruments in effect prior to the Distribution Date to which it
is a party, (A) upon surrender of a Right, pay cash equal to the Purchase Price
in lieu of issuing Preferred Shares and requiring payment therefor, (B) upon due
exercise of a Right and payment of the Purchase Price for each Preferred Share
as to which such Right is exercised, issue equity securities having a value
equal to the value of the Preferred Shares which otherwise would have been
issuable pursuant to Section 11, which value shall be determined by a nationally
recognized investment banking firm selected by the Board of Directors of the
Company, or (C) upon due exercise of a Right and payment of the Purchase Price
for each Preferred Share as to which such Right is exercised, distribute a
combination of Preferred Shares, cash and/or other equity and/or debt securities
having an aggregate value equal to the value of the Preferred Shares which
otherwise would have been issuable pursuant to Section 11, which value shall be
determined by a nationally recognized investment banking firm selected by the
Board of Directors of the Company. To the extent that any legal or contractual
restrictions (pursuant to agreements or instruments in effect prior to the
Distribution Date to which it is party) prevent the Company from paying the full
amount payable in accordance with the foregoing sentence, the Company shall pay
to holders of the Rights as to which such payments are being made all amounts
which are not then restricted on a pro rata basis as such payments become
permissible under such legal or contractual restrictions until such payments
have been paid in full.

          (c)  The Company covenants and agrees that it will take all such
action as may be necessary to ensure that all Preferred Shares delivered upon
exercise or exchange of Rights shall, at the time of delivery of the
certificates for such Preferred Shares (subject to payment of the Purchase
Price), be duly and validly authorized and issued and fully paid and
nonassessable shares.

                                 Page 30 of 80
<PAGE>
 
          (d)  So long as the Preferred Shares issuable upon the exercise or
exchange of Rights are to be listed on any national securities exchange, the
Company covenants and agrees to use its best efforts to cause, from and after
such time as the Rights become exercisable or exchangeable, all Preferred Shares
reserved for such issuance to be listed on such securities exchange upon
official notice of issuance upon such exercise or exchange.

          (e) The Company further covenants and agrees that it will pay when due
and payable any and all Federal and state transfer taxes and charges which may
be payable in respect of the issuance or delivery of Right Certificates or of
any Preferred Shares or Common Shares or other securities upon the exercise or
exchange of the Rights.  The Company shall not, however, be required to pay any
transfer tax which may be payable in respect of any transfer or delivery of
Right Certificates to a Person other than, or in respect of the issuance or
delivery of certificates for the Preferred Shares or Common Shares or other
securities, as the case may be, in a name other than that of, the registered
holder of the Right Certificate evidencing Rights surrendered for exercise or
exchange or to issue or deliver any certificates for Preferred Shares or Common
Shares or other securities  as the case may be, upon the exercise or exchange of
any Rights until any such tax shall have been paid (any such tax being payable
by the holder of such Right Certificate at the time of surrender) or until it
has been established to the Company's satisfaction that no such tax is due.

          SECTION 10.  PREFERRED SHARES RECORD DATE.  Each Person in whose name
any certificate for Preferred Shares or Common Shares or other securities is
issued upon the exercise or exchange of Rights shall for all purposes be deemed
to have become the holder of record of the Preferred Shares or Common Shares or
other securities, as the case may be, represented thereby on, and such
certificate shall be dated, the date upon which the Right Certificate evidencing
such Rights was duly surrendered and payment of any Purchase Price (and any
applicable transfer taxes) was made; provided, however, that, if the date of
such surrender and payment is a date upon which the transfer books of the
Company for the Preferred Shares or Common Shares or other securities, as

                                 Page 31 of 80
<PAGE>
 
the case may be, are closed, such Person shall be deemed to have become the
record holder of such Preferred Shares or Common Shares or other securities, as
the case may be, on, and such certificate shall be dated, the next succeeding
Business Day on which the transfer books of the Company for the Preferred Shares
or Common Shares or other securities, as the case may be, are open. Prior to the
exercise of the Rights evidenced thereby, the holder of a Right Certificate
shall not be entitled to any rights of a holder of Preferred Shares for which
the Rights shall be exercisable, including, without limitation, the right to
vote, to receive dividends or other distributions or to exercise any preemptive
rights, and shall not be entitled to receive any notice of any proceedings of
the Company, except as provided herein.

          SECTION 11.  ADJUSTMENTS IN RIGHTS AFTER THERE IS AN ACQUIRING PERSON;
EXCHANGE OF RIGHTS FOR SHARES; BUSINESS COMBINATIONS.  (a) Upon a Person
becoming an Acquiring Person, proper provision shall be made so that each holder
of a Right, except as provided in Section 7(e), shall thereafter have a right to
receive, upon exercise thereof for the Purchase Price in accordance with the
terms of this Rights Agreement, such number of one one hundredth (1/100th) of a
Preferred Share as shall equal the result obtained by multiplying the Purchase
Price by a fraction, the numerator of which is the number of one one-hundredth
(1/100th) of a Preferred Share for which a Right is then exercisable and the
denominator of which is 50% of the Market Value of the Common Shares on the date
on which a Person becomes an Acquiring Person.  As soon as practicable after a
Person becomes an Acquiring Person (provided the Company shall not have elected
to make the exchange permitted by Section 11(b)(I) for all outstanding Rights),
the Company covenants and agrees to use its best efforts to:

          (I) prepare and file a registration statement under the Securities
     Act, on an appropriate form, with respect to the Preferred Shares
     purchasable upon exercise of the Rights;

          (II) cause such registration statement to become effective as soon as
     practicable after such filing;

                                 Page 32 of 80
<PAGE>
 
          (III) cause such registration statement to remain effective (with a
     prospectus at all times meeting the requirements of the Securities Act)
     until the Expiration Date; and

          (IV) qualify or register the Preferred Shares purchasable upon
     exercise of the Rights under the blue sky or securities laws of such
     jurisdictions as may be necessary or appropriate.

          (b)(I) The Board of Directors of the Company may, at its option, at
any time after a Person becomes an Acquiring Person, mandatorily exchange all or
part of the then outstanding and exercisable Rights (which shall not include
Rights that shall have become null and void and nontransferable pursuant to the
provisions of Section 7(e)) for consideration per Right consisting of one-half
of the securities that would be issuable at such time upon the exercise of one
Right in accordance with Section 11(a) or, if applicable, Section 9(b)  (the
consideration issuable per Right pursuant to this Section 11(b)(I) being the
"Exchange Consideration").  The Board of Directors of the Company may, at its
option, issue, in substitution for Preferred Shares, Common Shares in an amount
per Preferred Share equal to the Formula Number (as defined in the Certificate
of Designation) if there are sufficient Common Shares either (a) issued but not
outstanding or (b) authorized but unissued.  If the Board of Directors of the
Company elects to exchange all the Rights for Exchange Consideration pursuant to
this Section 11(b)(I) prior to the physical distribution of the Rights
Certificates, the Company may distribute the Exchange Consideration in lieu of
distributing Right Certificates, in which case for purposes of this Rights
Agreement holders of Rights shall be deemed to have simultaneously received and
surrendered for exchange Right Certificates on the date of such distribution.

          (II) Any action of the Board of Directors of the Company ordering the
exchange of any Rights pursuant to Section 11(b)(I) shall be irrevocable and,
immediately upon the taking of such action and without any further action and
without any notice, the right to exercise any such Right pursuant to Section
11(a) shall terminate and the only right thereafter of a holder of

                                 Page 33 of 80
<PAGE>
 
such Right shall be to receive the Exchange Consideration in exchange for each
such Right held by such holder or, if the Exchange Consideration shall not have
been paid or issued, to exercise any such Right pursuant to Section 11(c)(I).
The Company shall promptly give public notice of any such exchange; provided,
however, that the failure to give, or any defect in, such notice shall not
affect the validity of such exchange. The Company promptly shall mail a notice
of any such exchange to all holders of such Rights at their last addresses as
they appear upon the registry books of the Rights Agent. Any notice which is
mailed in the manner herein provided shall be deemed given, whether or not the
holder receives the notice. Each such notice of exchange will state the method
by which the exchange of the Rights for the Exchange Consideration will be
effected and, in the event of any partial exchange, the number of Rights which
will be exchanged. Any partial exchange shall be effected pro rata based on the
number of Rights (other than Rights which shall have become null and void and
nontransferable pursuant to the provisions of Section 7(e)) held by each holder
of Riqhts.

          (c)(I) In the event that, following a Distribution Date, directly or
indirectly, any transactions specified in the following clause (i),  (ii) or
(iii) of this Section 11(c)  (each such transaction being a "Business
Combination") shall be consummated:

          (i) the Company shall consolidate with, or merge with and into, any
     Acquiring Person or any Affiliate or Associate of an Acquiring Person;

          (ii) any Acquiring Person or any Affiliate or Associate of an
     Acquiring Person shall merge with and into the Company and, in connection
     with such merger, all or part of the Common Shares shall be changed into or
     exchanged for capital stock or other securities of the Company or of any
     Acquiring Person or Affiliate or Associate of an Acquiring Person or cash
     or any other property; or

                                 Page 34 of 80
<PAGE>
 
          (iii) the Company shall sell, lease, exchange or otherwise transfer or
     dispose of (or one or more of its Subsidiaries shall sell, lease, exchange
     or otherwise transfer or dispose of), in one or more transactions, the
     Major Part of the assets of the Company and its Subsidiaries (taken as a
     whole) to any Acquiring Person or any Affiliate or Associate of an
     Acquiring Person,

then, in each such case, proper provision shall be made so that each holder of a
Right, except as provided in Section 7(e), shall thereafter have the right to
receive, upon the exercise thereof for the Purchase Price in accordance with the
terms of this Rights Agreement, the securities specified below (or, at such
holder's option, the securities specified in Section 11(a)):

          (A) If the Principal Party in such Business Combination has Registered
     Common Shares outstanding, each Right shall thereafter represent the right
     to receive, upon the exercise thereof for the Purchase Price in accordance
     with the terms of this Rights Agreement, such number of Registered Common
     Shares of such Principal Party, free and clear of all liens, encumbrances
     or other adverse claims, as shall have an aggregate Market Value equal to
     the result obtained by multiplying the Purchase Price by two;

          (B) If the Principal Party involved in such Business Combination does
     not have Registered Common Shares outstanding, each Right shall thereafter
     represent the right to receive, upon the exercise thereof for the Purchase
     Price in accordance with the terms of this Rights Agreement, at the
     election of the holder of such Right at the time of the exercise thereof,
     any of:

               (1) such number of Common Shares of the Surviving Person in such
          Business Combination as shall have an aggregate Book Value immediately
          after giving effect to such Business Combination equal to the result
          obtained by multiplying the Purchase Price by two;

                                 Page 35 of 80
<PAGE>
 
               (2) such number of Common Shares of the Principal Party in such
          Business Combination (if the Principal Party is not also the Surviving
          Person in such Business Combination) as shall have an aggregate Book
          Value immediately after giving effect to such Business Combination
          equal to the result obtained by multiplying the Purchase Price by two;
          or

               (3) if the Principal Party in such Business Combination is an
          Affiliate of one or more Persons which has Registered Common Shares
          outstanding, such number of Registered Common Shares of whichever of
          such Affiliates of the Principal Party has Registered Common Shares
          with the greatest aggregate Market Value on the date of consummation
          of such Business Combination as shall have an aggregate Market Value
          on the date of such Business Combination equal to the result obtained
          by multiplying the Purchase Price by two.

          (II) The Company shall not consummate any Business Combination unless
each issuer of Common Shares for which Rights may be exercised, as set forth in
this Section 11(c), shall have sufficient authorized Common Shares that have not
been issued or reserved for issuance (and which shall, when issued upon exercise
thereof in accordance with this Rights Agreement, be validly issued, fully paid
and nonassessable and free of preemptive rights, rights of first refusal or any
other restrictions or limitations on the transfer or ownership thereof) to
permit the exercise in full of the Rights in accordance with this Section 11(c)
and unless prior thereto:

          (i) a registration statement under the Securities Act on an
     appropriate form, with respect to the Rights and the Common Shares of such
     issuer purchasable upon exercise of the Rights, shall be effective under
     the Securities Act; and

          (ii) the Company and each such issuer shall have:

                                 Page 36 of 80
<PAGE>
 
               (A) executed and delivered to the Rights Agent a supplemental
          agreement providing for the assumption by such issuer of the
          obligations set forth in this Section 11(c)  (including the obligation
          of such issuer to issue Common Shares upon the exercise of Rights in
          accordance with the terms set forth in Sections 11(c)(I) and
          11(c)(III)) and further providing that such issuer, at its own
          expense, will use its best efforts to:

                    (1) cause a registration statement under the Securities Act
               on an appropriate form, with respect to the Rights and the Common
               Shares of such issuer purchasable upon exercise of the Rights, to
               remain effective (with a prospectus at all times meeting the
               requirements of the Securities Act) until the Expiration Date;

                    (2) qualify or register the Rights and the Common Shares of
               such issuer purchasable upon exercise of the Rights under the
               blue sky or securities laws of such jurisdictions as may be
               necessary or appropriate; and

                    (3) list the Rights and the Common Shares of such issuer
               purchasable upon exercise of the Rights on each national
               securities exchange on which the Common Shares were listed prior
               to the consummation of the Business Combination or, if the Common
               Shares were not listed on a national securities exchange prior to
               the consummation of the Business Combination, on a national
               securities exchange;

               (B) furnished to the Rights Agent a written opinion of
          independent counsel stating that such supplemental agreement is a
          valid, binding and enforceable agreement of such issuer; and

               (C) filed with the Rights Agent a certificate of a nationally
          recognized firm of independent accountants setting

                                 Page 37 of 80
<PAGE>
 
          forth the number of Common Shares of such issuer which may be
          purchased upon the exercise of each Right after the consummation of
          such Business Combination.

          (III) After consummation of any Business Combination and subject to
the provisions of Section 11(c)(II),  (i) each issuer of Common Shares for which
Rights may be exercised as set forth in this Section 11(c) shall be liable for,
and shall assume, by virtue of such Business Combination, all the obligations
and duties of the Company pursuant to this Rights Agreement, (ii) the term
"Company" shall thereafter be deemed to refer to such issuer,  (iii) each such
issuer shall take such steps in connection with such consummation as may be
necessary to assure that the provisions hereof (including the provisions of
Sections 11(a) and 11(c)) shall thereafter be applicable, as nearly as
reasonably may be, in relation to its Common Shares thereafter deliverable upon
the exercise of the Rights, and (iv) the number of Common Shares of each such
issuer thereafter receivable upon exercise of any Right shall be subject to
adjustment from time to time in a manner and on terms as nearly equivalent as
practicable to the provisions of Sections 11 and 12 and the provisions of
Section 7, 9 and 10 with respect to the Preferred Shares shall apply, as nearly
as reasonably may be, on like terms to any such Common Shares.

          SECTION 12.  CERTAIN ADJUSTMENTS.   (a) To preserve the actual or
potential economic value of the Rights, if at any time after the date of this
Rights Agreement there shall be any change in the Common Shares or the Preferred
Shares, whether by reason of stock dividends, stock splits, recapitalizations,
mergers, consolidations, combinations or exchanges of securities, split-ups,
splitoffs, spin-offs, liquidations, other similar changes in capitalization, any
distribution or issuance of cash, assets, evidences of indebtedness or
subscription rights, options or warrants to holders of Common Shares or
Preferred Shares, as the case may be (other than distribution of the Rights or
regular quarterly cash dividends) or otherwise, then, in each such event the
Board of Directors of the Company shall make such appropriate adjustments in the
number of Preferred Shares (or the number and

                                 Page 38 of 80
<PAGE>
 
kind of other securities) issuable upon exercise of each Right, the Purchase
Price and Redemption Price in effect at such time and the number of Rights
outstanding at such time (including the number of Rights or fractional Rights
associated with each Common Share) such that following such adjustment such
event shall not have had the effect of reducing or limiting the benefits the
holders of the Rights would have had absent such event.

          (b) If, as a result of an adjustment made pursuant to Section 12(a),
the holder of any Right thereafter exercised shall become entitled to receive
any securities other than Preferred Shares, thereafter the number of such
securities so receivable upon exercise of any Right shall be subject to
adjustment from time to time in a manner and on terms as nearly equivalent as
practicable to the provisions of Sections 11 and 12 and the provisions of
Sections 7, 9 and 10 with respect to the Preferred Shares shall apply, as nearly
as reasonably may be, on like terms to any such other securities.

          (c) All Rights originally issued by the Company subsequent to any
adjustment made to the amount of Preferred Shares or other securities relating
to a Right shall evidence the right to purchase, for the Purchase Price, the
adjusted number and kind of securities purchasable from time to time hereunder
upon exercise of the Rights, all subject to further adjustment as provided
herein.

          (d) Irrespective of any adjustment or change in the Purchase Price or
the number of Preferred Shares or number or kind of other securities issuable
upon the exercise of the Rights, the Right Certificates theretofore and
thereafter issued may continue to express the terms which were expressed in the
initial Right Certificates issued hereunder.

          (e) In any case in which action taken pursuant to Section 12(a)
requires that an adjustment be made effective as of a record date for a
specified event, the Company may elect to defer until the occurrence of such
event the issuing to the holder of any Right exercised after such record date
the Preferred Shares and/or other securities, if any, issuable upon such

                                 Page 39 of 80
<PAGE>
 
exercise over and above the Preferred Shares and/or other securities, if any,
issuable before giving effect to such adjustment; provided, however, that the
Company shall deliver to such holder a due bill or other appropriate instrument
evidencing such holder's right to receive such additional securities upon the
occurrence of the event requiring such adjustment.

          SECTION 13.  CERTIFICATE OF ADJUSTMENT. Whenever an adjustment is made
as provided in Section 11 or 12, the Company shall (a) promptly prepare a
certificate setting forth such adjustment and a brief statement of the facts
accounting for such adjustment (b) promptly file with the Rights Agent and with
each transfer agent for the Preferred Shares a copy of such certificate and (c)
mail a brief summary thereof to each holder of a Right Certificate (or, prior to
the Distribution Date, of the Common Shares) in accordance with Section 25.  The
Rights Agent shall be fully protected in relying on any such certificate and on
any adjustment therein contained.

          SECTION 14.  ADDITIONAL COVENANTS.  (a) Notwithstanding any other
provision of this Rights Agreement, no adjustment to the number of Preferred
Shares (or fractions of a share) or other securities for which a Right is
exercisable or the number of Rights outstanding or associated with each Common
Share or any similar or other adjustment shall be made or be effective if such
adjustment would have the effect of reducing or limiting the benefits the
holders of the Rights would have had absent such adjustment, including, without
limitation, the benefits under Sections 11 and 12, unless the terms of this
Rights Agreement are amended so as to preserve such benefits.

          (b) The Company covenants and agrees that, after the Distribution
Date, except as permitted by Section 26, it will not take (or permit any
Subsidiary of the Company to take) any action if at the time such action is
taken it is intended or reasonably foreseeable that such action will reduce or
otherwise limit the benefits the holders of the Rights would have had absent
such action, including, without limitation, the benefits under Sections 11 and
12.  Any action taken by the Company during any period after any Person becomes
an Acquiring Person but prior to the Distribution Date shall be null

                                 Page 40 of 80
<PAGE>
 
and void unless such action could be taken under this Section 14(b) from and
after the Distribution Date. The Company shall not consummate any Business
Combination if any issuer of Common Shares for which Rights may be exercised
after such Business Combination in accordance with Section 11(c) shall have
taken any action that reduces or otherwise limits the benefits the holders of
the Rights would have had absent such action, including, without limitation, the
benefits under Sections 11 and 12.

          SECTION 15.  FRACTIONAL RIGHTS AND FRACTIONAL SHARES. (a)  The Company
may, but shall not be required to, issue fractions of Rights or distribute Right
Certificates which evidence fractional Rights.  In lieu of such fractional
Rights, the Company may pay to the registered holders of the Right Certificates
with regard to which such fractional Rights would otherwise be issuable an
amount in cash equal to the same fraction of the current market value of a whole
Right.  For purposes of this Section 15(a), the current market value of a whole
Right shall be the closing price of the Rights (as determined pursuant to the
second and third sentences of the definition of Market Value contained in
Section 1) for the Trading Day immediately prior to the date on which such
fractional Rights would have been otherwise issuable.

          (b) The Company may, but shall not be required to, issue fractions of
Preferred Shares upon exercise of the Rights or distribute certificates which
evidence fractional Preferred Shares.  In lieu of fractional Preferred Shares,
the Company may elect to (i) utilize a depository arrangement as provided by the
terms of the Preferred Shares or (ii) in the case of a fraction of a Preferred
Share (other than one one-hundredth (1/100th) of a Preferred Share or any
integral multiple thereof), pay to the registered holders of Right Certificates
at the time such Rights are exercised as herein provided an amount in cash equal
to the same fraction of the current market value of one Preferred Share, if any
are outstanding and publicly traded (or the Formula Number times the current
market value of one Common Share if the Preferred Shares are not outstanding and
publicly traded).  For purposes of this Section 15(b), the current market value
of a Preferred Share (or Common Share) shall be the closing price of a Preferred
Share (or Common Share)  (as

                                 Page 41 of 80
<PAGE>
 
determined pursuant to the second and third sentences of the definition of
Market Value contained in Section 1) for the Trading Day immediately prior to
the date of such exercise. If, as a result of an adjustment made pursuant to
Section 12(a), the holder of any Right thereafter exercised shall become
entitled to receive any securities other than Preferred Shares, the provisions
of this Section 15(b) shall apply, as nearly as reasonably may be, on like terms
to such other securities.

          (c) The Company may, but shall not be required to, issue fractions of
Common Shares upon exchange of Rights pursuant to Section 11(b), or to
distribute certificates which evidence fractional Common Shares.  In lieu of
such fractional Common Shares, the Company may pay to the registered holders of
the Right Certificates with regard to which such fractional Common Shares would
otherwise be issuable an amount in cash equal to the same fraction of the
current Market Value of one Common Share as of the date on which a Person became
an Acquiring Person.

          (d) The holder of Rights by the acceptance of the Rights expressly
waives his right to receive any fractional Rights or any fractional shares upon
exercise of a Right except as provided in this Section 15.

          SECTION 16.  RIGHTS OF ACTION.  (a) All rights of action in respect of
this Rights Agreement are vested in the respective registered holders of the
Right Certificates (and, prior to the Distribution Date, the registered holders
of the Common Shares), and any registered holder of any Right Certificate (or,
prior to the Distribution Date, of the Common Shares), without the consent of
the Rights Agent or of the holder of any other Right Certificate (or, prior to
the Distribution Date, of the Common Shares) may, in his own behalf and for his
own benefit, enforce, and may institute and maintain any suit, action or
proceeding against the Company to enforce, or otherwise act in respect of, his
right to exercise the Rights evidenced by such Right Certificate in the manner
provided in such Right Certificate and in this Rights Agreement.  Without
limiting the foregoing or any remedies available to the holders of Rights, it is
specifically acknowledged that the

                                 Page 42 of 80
<PAGE>
 
holders of Rights would not have an adequate remedy at law for any breach of
this Rights Agreement and shall be entitled to specific performance of the
obligations of any Person under, and injunctive relief against actual or
threatened violations of the obligations of any Person subject to, this Rights
Agreement.

          (b) Any holder of Rights who prevails in an action to enforce the
provisions of this Rights Agreement shall be entitled to recover the reasonable
costs and expenses, including attorneys' fees, incurred in such action.

          SECTION 17.  TRANSFER AND OWNERSHIP OF RIGHTS AND RIGHT CERTIFICATES.
(a) Prior to the Distribution Date, the Rights will be transferable only in
connection with the transfer of the Common Shares.

          (b) After the Distribution Date, the Right Certificates will be
transferable, subject to Section 7(e), only on the registry books of the Rights
Agent if surrendered at the principal office of the Rights Agent, duly endorsed
or accompanied by a proper instrument of transfer.

          (c) The Company and the Rights Agent may deem and treat the Person in
whose name a Right Certificate (or, prior to the Distribution Date, the
associated Common Shares certificate) is registered as the absolute owner
thereof and of the Rights evidenced thereby (notwithstanding any notations of
ownership or writing on the Right Certificates or the associated certificate for
Common Shares made by anyone other than the Company or the Rights Agent) for all
purposes whatsoever, and neither the Company nor the Rights Agent shall be
affected by any notice to the contrary.

          SECTION 18.  RIGHT CERTIFICATE HOLDER NOT DEEMED A STOCKHOLDER.  No
holder, as such, of any Right Certificate shall be entitled to vote or receive
dividends or be deemed, for any purpose, the holder of the Preferred Shares or
of any other securities of the Company which may at any time be

                                 Page 43 of 80
<PAGE>
 
issuable on the exercise of the Rights represented thereby, nor shall anything
contained herein or in any Right Certificate be construed to confer upon the
holder of any Right Certificate, as such, any of the rights of a stockholder of
the Company, including, without limitation, any right to vote for the election
of directors or upon any matter submitted to stockholders at any meeting
thereof, or to give or withhold consent to any corporate action, or to receive
notice of meetings or other actions affecting stockholders, or to receive
dividends or other distributions or subscription rights, or otherwise, until the
Right or Rights evidenced by such Right Certificate shall have been exercised in
accordance with the provisions hereof.

          SECTION 19.  CONCERNING THE RIGHTS AGENT.  (a) The Company agrees to
pay to the Rights Agent reasonable compensation for all services rendered by it
hereunder and from time to time, on demand of the Rights Agent, its reasonable
expenses and counsel fees and other disbursements incurred in the administration
and execution of this Rights Agreement and the exercise and performance of its
duties hereunder.

          (b) The Rights Agent shall be protected and shall incur no liability
for or in respect of any action taken, suffered or omitted by it in connection
with its administration of this Rights Agreement in reliance upon any Right
Certificate or certificate for the Common Shares or for other securities of the
Company, instrument of assignment or transfer, power of attorney, endorsement,
affidavit, letter, notice, direction, consent, certificate, statement, or other
paper or document believed by it to be genuine and to be signed, executed and,
where necessary, verified or acknowledged, by the proper Person or Persons.

          SECTION 20.  MERGER OR CONSOLIDATION OR CHANGE OF RIGHTS AGENT.  (a)
Any corporation into which the Rights Agent or any successor Rights Agent may be
merged or with which it may be consolidated, or any corporation resulting from
any merger or consolidation to which the Rights Agent or any successor Rights 
Agent shall be a party, or any corporation succeeding to the stock transfer or 
corporate trust business of the Rights Agent or any

                                 Page 44 of 80
<PAGE>
 
successor Rights Agent, shall be the successor to the Rights Agent under this
Rights Agreement without the execution or filing of any paper or any further act
on the part of any of the parties hereto; provided that such corporation would
be eligible for appointment as a successor Rights Agent under the provisions of
Section 22. In case, at the time such successor Rights Agent shall succeed to
the agency created by this Rights Agreement, any of the Right Certificates shall
have been countersigned but not delivered, any such successor Rights Agent may
adopt the countersignature of the predecessor Rights Agent and deliver such
Right Certificates so countersigned; and, in case at that time any of the Right
Certificates shall not have been countersigned, any successor Rights Agent may
countersign such Right Certificates either in the name of the predecessor Rights
Agent or in the name of the successor Rights Agent; and in all such cases such
Right Certificates shall have the full force provided in the Right Certificates
and in this Rights Agreement.

          (b) In case at any time the name of the Rights Agent shall be changed
and at such time any of the Right Certificates shall have been countersigned but
not delivered, the Rights Agent may adopt the countersignature under its prior
name and deliver Right Certificates so countersigned; and, in case at that time
any of the Right Certificates shall not have been countersigned, the Rights
Agent may countersign such Right Certificates either in its prior name or in its
changed name; and in all such cases such Right Certificates shall have the full
force provided in the Right Certificates and in this Rights Agreement.

          SECTION 21.  DUTIES OF RIGHTS AGENT. The Rights Agent undertakes the
duties and obligations imposed by this Rights Agreement upon the following terms
and conditions, by all of which the Company and the holders of Right
Certificates (or, prior to the Distribution Date, of the Common Shares), by
their acceptance thereof, shall be bound:

          (a) The Rights Agent may consult with legal counsel (who may be legal
counsel for the Company), and the opinion of such counsel shall be full 

                                 Page 45 of 80
<PAGE>
 
and complete authorization and protection to the Rights Agent as to any action
taken, suffered or omitted by it in good faith and in accordance with such
opinion.

          (b) Whenever in the performance of its duties under this Rights
Agreement the Rights Agent shall deem it necessary or desirable that any fact or
matter (including, without limitation, the identity of any Acquiring Person) be
proved or established by the Company prior to taking, refraining from taking or
suffering any action hereunder, such fact or matter (unless other evidence in
respect thereof be herein specifically prescribed) may be deemed to be
conclusively proved and established by a certificate signed by any one of the
Chairman of the Board, the Chief Executive Officer, the President, the Chief
Operating Officer, the Chief Financial Officer, a Vice President (whether
preceded by any additional title), the Treasurer or the Secretary of the Company
and delivered to the Rights Agent; and such certificate shall be full
authorization to the Rights Agent for any action taken or suffered in good faith
by it under the provisions of this Rights Agreement in reliance upon such
certificate.

          (c) The Rights Agent shall be liable hereunder only for its own gross
negligence, bad faith or wilful misconduct.

          (d) The Rights Agent shall not be liable for or by reason of any of
the statements of fact or recitals contained in this Rights Agreement or in the
Right Certificates (except as to its countersignature thereof) or be required to
verify the same, but all such statements and recitals are and shall be deemed to
have been made by the Company only.

          (e) The Rights Agent shall not be under any responsibility in respect
of the validity of this Rights Agreement or the execution and delivery hereof
(except the due execution hereof by the Rights Agent) or in respect of the
validity or execution of any Right Certificate (except its countersignature
thereof); nor shall it be responsible for any breach by the Company of any
covenant or condition contained in this Rights Agreement or in

                                 Page 46 of 80
<PAGE>
 
any Right Certificate; nor shall it be responsible for any adjustment required
under the provisions of Section 11 or 12 or responsible for the manner, method
or amount of any such adjustment or the ascertaining of the existence of facts
that would require any such adjustment (except with respect to the exercise of
Rights evidenced by Right Certificates after actual notice of any such
adjustment); nor shall it by any act hereunder be deemed to make any
representation or warranty as to the authorization or reservation of any
Preferred Shares or Common Shares to be issued pursuant to this Rights Agreement
or any Right Certificate or as to whether any Preferred Shares or Common Shares
will, when so issued, be validly authorized and issued, fully paid and
nonassessable.

          (f) The Company agrees that it will perform, execute, acknowledge and
deliver or cause to be performed, executed, acknowledged and delivered all such
further and other acts, instruments and assurances as may reasonably be required
by the Rights Agent for the carrying out or performing by the Rights Agent of
the provisions of this Rights Agreement.

          (g) The Rights Agent is hereby authorized and directed to accept
instructions with respect to the performance of its duties hereunder from any
one of the Chairman of the Board, the Chief Executive Officer, the President,
the Chief Operating Officer, a Vice President (whether preceded by any
additional title), the Secretary or the Treasurer of the Company, in connection
with its duties and it shall not be liable for any action taken or suffered to
be taken by it in good faith in accordance with instructions of any such
officer.

          (h) The Rights Agent and any stockholder, director, officer or
employee of the Rights Agent may buy, sell or deal in any of the Rights or other
securities of the Company or become pecuniarily interested in any transaction in
which the Company may be interested, or contract with or lend money to the
Company or otherwise act as fully and freely as though it were not the Rights
Agent under this Rights Agreement.  Nothing herein shall

                                 Page 47 of 80
<PAGE>
 
preclude the Rights Agent from acting in any other capacity for the Company or
for any other legal entity.

          (i) The Rights Agent may execute and exercise any of the rights or
powers hereby vested in it or perform any duty hereunder either itself or by or
through its attorneys or agents, and the Rights Agent shall not be answerable or
accountable for any act, default, neglect or misconduct of any such attorneys or
agents or for any loss to the Company resulting from any such act, default,
neglect or misconduct provided reasonable care was exercised in the selection
and continued employment thereof.

          (j) The Company agrees to indemnify and to hold the Rights Agent
harmless against any loss, liability, damage or expense (including reasonable
fees and expenses of legal counsel) which the Rights Agent may incur resulting
from its actions as Rights Agent pursuant to this Rights Agreement; provided,
however, that the Rights Agent shall not be indemnified or held harmless with
respect to any such loss, liability, damage or expense incurred by the Rights
Agent as a result of, or arising out of, its own gross negligence, bad faith or
wilful misconduct.  Anything in this Agreement to the contrary notwithstanding,
in no event shall the Agent be liable for special, indirect or consequential
loss or damage of any kind whatsoever (including but not limited to lost
profits), even if the Agent has been advised of the likelihood of such loss or
damage and regardless of the form of the action.  In no case shall the Company
be liable with respect to any action, proceeding, suit or claim against the
Rights Agent unless the Rights Agent shall have notified the Company, by letter
or by facsimile confirmed by letter, of the assertion of any action, proceeding,
suit or claim against the Rights Agent, promptly after the Rights Agent shall
have notice of any such assertion of an action, proceeding, suit or claim or
have been served with the summons or other first legal process giving
information as to the nature and basis of the action, proceeding, suit or claim.
The Company shall be entitled to participate at its own expense in the defense
of any such action, proceeding, suit or claim, and, if the Company so elects,
the Company shall assume the defense of any such action, proceeding, suit or
claim.  In the event that the Company assumes 

                                 Page 48 of 80
<PAGE>
 
such defense, the Company shall not thereafter be liable for the fees and
expenses of any additional counsel retained by the Rights Agent, so long as the
Company shall retain counsel satisfactory to the Rights Agent, in the exercise
of its reasonable judgment, to defend such action, proceeding, suit or claim.
The Rights Agent agrees not to settle any litigation in connection with any
action, proceeding, suit or claim with respect to which it may seek
indemnification from the Company without the prior written consent of the
Company.

          SECTION 22.  CHANGE OF RIGHTS AGENT.  The Rights Agent or any
successor Rights Agent may resign and be discharged from its duties under this
Rights Agreement upon 30 days' notice in writing mailed to the Company and to
each transfer agent of the Common Shares and the Preferred Shares by registered
or certified mail, and to the holders of the Right Certificates (or, prior to
the Distribution Date, of the Common Shares) by first-class mail.  The Company
may remove the Rights Agent or any successor Rights Agent upon 30 days' notice
in writing, mailed to the Rights Agent or successor Rights Agent, as the case
may be, and to each transfer agent of the Common Shares and the Preferred Shares
by registered or certified mail, and to the holders of the Right Certificates
(or, prior to the Distribution Date, of the Common Shares) by first-class mail.
If the Rights Agent shall resign or be removed or shall otherwise become
incapable of acting, the Company shall appoint a successor to the Rights Agent.
If the Company shall fail to make such appointment within a period of 30 days
after giving notice of such removal or after it has been notified in writing of
such resignation or incapacity by the resigning or incapacitated Rights Agent or
by the holder of a Right Certificate (or, prior to the Distribution Date, of the
Common Shares) (who shall, with such notice, submit his Right Certificate or,
prior to the Distribution Date, the certificate representing his Common Shares,
for inspection by the Company), then the registered holder of any Right
Certificate (or, prior to the Distribution Date, of the Common Shares) may apply
to any court of competent jurisdiction for the appointment of a new Rights
Agent.  Any successor Rights Agent, whether appointed by the Company or by such
a court, shall be a corporation organized and doing business under the

                                 Page 49 of 80
<PAGE>
 
laws of the United States or of the State of New York (or of any other state of
the United States so long as such corporation is authorized to conduct a stock
transfer or corporate trust business in the State of New York), in good
standing, having a principal office in the State of New York, which is
authorized under such laws to exercise stock transfer or corporate trust powers
and is subject to supervision or examination by Federal or state authority and
which has at the time of its appointment as Rights Agent a combined capital and
surplus of at least $50,000,000; provided that the principal transfer agent for
the Common Shares shall in any event be qualified to be the Rights Agent. After
appointment, the successor Rights Agent shall be vested with the same powers,
rights, duties and responsibilities as if it had been originally named as Rights
Agent without further act or deed; but the predecessor Rights Agent shall
deliver and transfer to the successor Rights Agent any property at the time held
by it hereunder, and execute and deliver any further assurance, conveyance, act
or deed necessary for the purpose. Not later than the effective date of any such
appointment, the Company shall file notice thereof in writing with the
predecessor Rights Agent and each transfer agent of the Common Shares and the
Preferred Shares, and mail a notice thereof in writing to the registered holders
of the Right Certificates (or, prior to the Distribution Date, of the Common
Shares). Failure to give any notice provided for in this Section 22, however, or
any defect therein shall not affect the legality or validity of the resignation
or removal of the Rights Agent or the appointment of the successor Rights Agent,
as the case may be.

          SECTION 23.  ISSUANCE OF ADDITIONAL RIGHTS AND RIGHT CERTIFICATES.
Notwithstanding any of the provisions of this Rights Agreement or of the Rights
to the contrary, the Company may, at its option, issue new Right Certificates
evidencing Rights in such form as may be approved by its Board of Directors to
reflect any adjustment or change made in accordance with the provisions of this
Rights Agreement.  In addition, in connection with the issuance or sale of
Common Shares following the Distribution Date and prior to the earlier of the
Redemption Date and the Expiration Date, the Company (a) shall, with respect to
Common Shares so issued or sold pursuant to the exercise of stock options or
under any employee plan or arrangement, or upon

                                 Page 50 of 80
<PAGE>
 
the exercise, conversion or exchange of securities, notes or debentures issued
by the Company, and (b) may, in any other case, if deemed necessary or
appropriate by the Board of Directors of the Company, issue Right Certificates
representing the appropriate number of Rights in connection with such issuance
or sale; provided, however, that (i) no such Right Certificate shall be issued
if, and to the extent that, the Company shall be advised by counsel that such
issuance would create a significant risk of material adverse tax consequences to
the Company or the Person to whom such Right Certificate would be issued, and
(ii) no such Right Certificate shall be issued if, and to the extent that,
appropriate adjustment shall otherwise have been made in lieu of the issuance
thereof.

          SECTION 24.  REDEMPTION AND TERMINATION.  (a) The Board of Directors
of the Company may, at its option, at any time prior to the earlier of (i) the
close of business on the tenth day following the time  the Company learns that a
Person has become an Acquiring Person and (ii) the Expiration Date, order the
redemption of all, but not fewer than all, the then outstanding Rights at the
Redemption Price (the date of such redemption being the "Redemption Date"), and
the Company, at its option, may pay the Redemption Price either in cash or
Common Shares or other securities of the Company deemed by the Board of
Directors of the Company, in the exercise of its sole discretion, to be at least
equivalent in value to the Redemption Price; provided, however, that, in
addition to any other limitations contained herein on the right to redeem
outstanding Rights (including the occurrence of any event or the expiration of
any period after which the Rights may no longer be redeemed), for the 120-day
period after any date of a change (resulting from a proxy or consent
solicitation) in a majority of the Board of Directors of the Company in office
at the commencement of such solicitation, the Rights may only be redeemed if (A)
there are directors then in office who were in office at the commencement of
such solicitation and (B) the Board of Directors of the Company, with the
concurrence of a majority of such directors then in office, determines that such
redemption is, in their judgment, in the best interests of the Company and its
stockholders.

                                 Page 51 of 80
<PAGE>
 
          (b) Immediately upon the action of the Board of Directors of the
Company ordering the redemption of the Rights, and without any further action
and without any notice, the right to exercise the Rights will terminate and the
only right thereafter of the holders of Rights shall be to receive the
Redemption Price.  Within 10 Business Days after the action of the Board of
Directors of the Company ordering the redemption of the Rights, the Company
shall give notice of such redemption to the holders of the then outstanding
Rights by mailing such notice to all such holders at their last addresses as
they appear upon the registry books of the Rights Agent or, prior to the
Distribution Date, on the registry books of the transfer agent for the Common
Shares.  Each such notice of redemption will state the method by which payment
of the Redemption Price will be made.  The notice, if mailed in the manner
herein provided, shall be conclusively presumed to have been duly given, whether
or not the holder of Rights receives such notice.  In any case, failure to give
such notice by mail, or any defect in the notice, to any particular holder of
Rights shall not affect the sufficiency of the notice to other holders of
Rights.

          SECTION 25.  NOTICES.  Notices or demands authorized by this Agreement
to be given or made by the Rights Agent or by the holder of a Right Certificate
(or, prior to the Distribution Date, of the Common Shares) to or on the Company
shall be sufficiently given or made if sent by first-class mail, postage
prepaid, addressed (until another address is filed in writing with the Rights
Agent) as follows:

          Unit Corporation
          1000 Kensington Tower I
          7130 South Lewis
          Tulsa, Oklahoma 74136

          Attention of the General Counsel

Subject to the provisions of Section 22, any notice or demand authorized by this
Rights Agreement to be given or made by the Company or by the holder of a Right
Certificate (or, prior to the Distribution Date, of the Common Shares) 

                                 Page 52 of 80
<PAGE>
 
to or on the Rights Agent shall be sufficiently given or made if sent by first-
class mail, postage prepaid, addressed (until another address is filed in
writing with the Company) as follows:

          Chemical Bank
          450 West 33rd Street
          New York, New York 10001
          Attention of Thomas Watt

Notices or demands authorized by this Rights Agreement to be given or made by
the Company or the Rights Agent to any holder of a Right Certificate (or, prior
to the Distribution Date, of the Common Shares) shall be sufficiently given or
made if sent by first-class mail, postage prepaid, addressed to such holder at
the address of such holder as shown on the registry books of the Rights Agent
or, prior to the Distribution Date, on the registry books of the transfer agent
for the Common Shares.

          SECTION 26.  SUPPLEMENTS AND AMENDMENTS.  At any time prior to the
Distribution Date and subject to the last sentence of this Section 26, the
Company may, and the Rights Agent shall if the Company so directs, supplement or
amend any provision of this Rights Agreement (including, without limitation, the
date on which the Distribution Date shall occur, the time during which the
Rights may be redeemed pursuant to Section 24 or any provision of the
Certificate of Designation) without the approval of any holder of the Rights.
Without limiting the foregoing, the Company may at any time prior to such time
as any Person becomes an Acquiring Person amend this agreement to (a)
specifically exempt any Person from being or being deemed to be an Acquiring
Person, subject to such terms and conditions as the Company deems appropriate,
(b) fix an expiration date later than the date set forth in Section 7 hereof or
(c) increase the Purchase Price.  From and after the Distribution Date and
subject to applicable law, the Company may, and the Rights Agent shall if the
Company so directs, amend this Rights Agreement without the approval of any
holders of Right Certificates (i) to cure any ambiguity or to correct or
supplement any provision contained herein which may be defective or inconsistent
with any other provision of this Rights Agreement or (ii) to make any other
provisions in regard to matters or questions arising hereunder which the Company
may deem necessary or desirable and which shall not adversely affect the
interests of the holders of Right Certificates (other than an Acquiring Person
or an Affiliate or Associate of an Acquiring Person).  Any supplement or
amendment adopted during any period after any Person has become an Acquiring
Person but prior to the Distribution Date shall be null and void unless such
supplement or amendment could have been adopted under the prior sentence from
and after the Distribution Date.  Any supplement or amendment to this Rights
Agreement duly approved by the Company that does not amend Sections 19, 20, 21
or 22 in a manner adverse to the Rights Agent shall become effective immediately
upon execution by the Company, whether or not also executed by the Rights Agent.
Notwithstanding anything contained in this Rights Agreement to the contrary,
during the 120-day period after any date of 

                                 Page 53 of 80
<PAGE>
 
a change (resulting from a proxy or consent solicitation) in a majority of the
Board of Directors of the Company in office at the commencement of such
solicitation, this Rights Agreement may be supplemented or amended only if (A)
there are directors then in office who were in office at the commencement of
such solicitation and (B) the Board of Directors of the Company, with the
concurrence of a majority of such directors then in office, determines that such
supplement or amendment is, in their judgment, in the best interests of the
Company and its stockholders and, after the Distribution Date, the holders of
the Right Certificates. In addition, notwithstanding anything to the contrary
contained in this Rights Agreement, no supplement or amendment to this Rights
Agreement shall be made which (a) reduces the Redemption Price (except as
required by Section 12(a)) or (b) provides for an earlier Expiration Date.

          SECTION 27.  SUCCESSORS.  All the covenants and provisions of this
Rights Agreement by or for the benefit of the Company or the Rights Agent shall
bind and inure to the benefit of their respective successors and assigns
hereunder.

          SECTION 28.  BENEFITS OF RIGHTS AGREEMENT; DETERMINATIONS AND ACTIONS
BY THE BOARD OF DIRECTORS, ETC.  (a) Nothing in this Rights Agreement shall be
construed to give to any Person other than the Company, the Rights Agent and the
registered holders of the Right Certificates (and, prior to the Distribution
Date, of the Common Shares) any legal or equitable right, remedy or claim under
this Rights Agreement; but this Rights Agreement shall be for the sole and
exclusive benefit of the Company, the Rights Agent and the registered holders of
the Right Certificates (and, prior to the Distribution Date, of the Common
Shares).

          (b) Except as explicitly otherwise provided in this Rights Agreement,
the Board of Directors of the Company shall have the exclusive power and
authority to administer this Rights Agreement and to exercise all rights and
powers specifically granted to the Board of Directors of the Company or to the
Company, or as may be necessary or advisable in the administration of this
Rights Agreement, including, without limitation, the right and power to (i)
interpret the provisions of this Rights Agreement and (ii) make all
determinations deemed necessary or advisable for the administration of this
Rights Agreement (including, without limitation, a determination to redeem or
not redeem the Rights or to amend this Rights Agreement and whether there is an
Acquiring Person).  All such actions, calculations, determinations and
interpretations which are done or made by the Board of Directors of the Company
in good faith shall be final, conclusive and binding on the Company, the Rights
Agent, the holders of the Rights and all other parties and shall not subject the
Board of Directors of the Company to any liability to the holders of the Rights.

          (c) Nothing contained in this Rights Agreement shall be deemed to be
in derogation of the obligation of the Board of Directors of the Company to
exercise its fiduciary duty.  Without limiting the foregoing, nothing contained
herein shall be construed to suggest or imply that the Board of 

                                 Page 54 of 80
<PAGE>
 
Directors shall not be entitled to reject any tender offer, or to recommend that
holders of Common Shares reject any tender offer, or to take any other action
(including, without limitation, the commencement, prosecution, defense or
settlement of any litigation and the submission of additional or alternative
offers or other proposals) with respect to any tender offer that the Board of
Directors believes is necessary or appropriate in the exercise of such fiduciary
duty.

          SECTION 29.  SEVERABILITY.  If any term, provision, covenant or
restriction of this Rights Agreement is held by a court of competent
jurisdiction or other authority to be invalid, void or unenforceable, the
remainder of the terms, provisions, covenants and restrictions of this Rights
Agreement shall remain in full force and effect and shall in no way be affected,
impaired or invalidated.

          SECTION 30.  GOVERNING LAW.  This Rights Agreement and each Right
Certificate issued hereunder shall be deemed to be a contract made under the law
of the State of Delaware and for all purposes shall be governed by and construed
in accordance with the law of such State applicable to contracts to be made and
performed entirely within such State.

          SECTION 31.  COUNTERPARTS; EFFECTIVENESS.  This Rights Agreement may
be executed in any number of counterparts and each of such counterparts shall
for all purposes be deemed to be an original, and all such counterparts shall
together constitute but one and the same instrument.  This Rights Agreement
shall be effective as of the Close of Business on the date hereof.

          SECTION 32.  DESCRIPTIVE HEADINGS.  Descriptive headings of the
several Sections of this Rights Agreement are inserted for convenience only and
shall not control or affect the meaning or construction of any of the provisions
of this Rights Agreement.

          IN WITNESS WHEREOF, the parties hereto have caused this Rights
Agreement to be duly executed as of the day and year first above written.

                                    UNIT CORPORATION


                                    by     /s/ John  G. Nikkel
                                      -------------------------
                                         Name:  John G. Nikkel
                                         Title: President

                                    Chemical Bank, as Rights
                                    Agent,


                                    by     /s/ Thomas Maupin
                                      -------------------------
                                         Name:  Thomas Maupin
                                         Title: Vice President

                                 Page 55 of 80
<PAGE>
 
                         Exhibits to Rights Agreement.

                                 Page 56 of 80

<PAGE>
 
                                                                    EXHIBIT 1(A)

                       CERTIFICATE OF THE VOTING POWERS,
                    DESIGNATIONS, PREFERENCES AND RELATIVE
                   PARTICIPATING, OPTIONAL AND OTHER SPECIAL
                    RIGHTS AND QUALIFICATIONS, LIMITATIONS
                          OR RESTRICTIONS OF SERIES A
                           PARTICIPATING CUMULATIVE
                              PREFERRED STOCK OF
                               UNIT CORPORATION


          Pursuant to Section 151 of the General Corporation Law of the State of
Delaware, Unit Corporation (the "Corporation", a corporation organized and
existing under the General Corporation Law of the State of Delaware, in
accordance with the provisions of Section 103 thereof, DOES HEREBY CERTIFY:

          That, pursuant to the authority conferred upon the Board of Directors
of the Corporation by Section 2 of Article Four of the Restated Certificate of
Incorporation of the Corporation (the "Certificate of Incorporation"), the Board
of Directors of the Corporation as of May 19, 1995, adopted the following
resolution creating a series of Preferred Stock designated as Series A
Participating Cumulative Preferred Stock:

          RESOLVED, that, pursuant to the authority vested in the Board of
     Directors of the Corporation in accordance with the provisions of the
     Restated Certificate of Incorporation of the Corporation, a series of
     Preferred Stock of the Corporation is hereby created and that the
     designation and number of shares thereof and the voting powers, preferences
     and relative, participating, optional and other special rights of the
     shares of such series, and the qualifications, limitations or restrictions
     thereof are as follows:

          SECTION 1.  DESIGNATION AND NUMBER OF SHARES.  The shares of such
series shall be designated as "Series A Participating Cumulative Preferred
Stock" (the "Series A Preferred Stock"), par value $1.00 per share.  The number
of shares initially constituting the Series A Preferred Stock shall be

                                 Page 57 of 80
<PAGE>
 
250,000; provided, however, that, if more than a total of 250,000 shares of
Series A Preferred Stock shall be issuable upon the exercise of Rights (the
"Rights") issued pursuant to the Rights Agreement dated as of May 19, 1995,
between the Corporation and Chemical Bank, a New York banking corporation, as
Rights Agent (the"Rights Agreement"), the Board of Directors of the Corporation,
pursuant to Section 151(g) of the General Corporation Law of the State of
Delaware, shall direct by resolution or resolutions that a certificate be
properly executed, acknowledged, filed and recorded, in accordance with the
provisions of Section 103 thereof, providing for the total number of shares of
Series A Preferred Stock authorized to be issued to be increased (to the extent
that the Certificate of Incorporation then permits) to the largest number of
whole shares (rounded up to the nearest whole number) issuable upon exercise of
such Rights.

          SECTION 2.  DIVIDENDS OR DISTRIBUTIONS.  (a) Subject to the prior and
superior rights of the holders of shares of any other series of Preferred Stock
or other class of capital stock of the Corporation ranking prior and superior to
the shares of Series A Preferred Stock with respect to dividends, the holders of
shares of the Series A Preferred Stock shall be entitled to receive, when, as
and if declared by the Board of Directors, out of the assets of the Corporation
legally available therefor,  (1) quarterly dividends payable in cash on the last
day of each fiscal quarter in each year, or such other dates as the Board of
Directors of the Corporation shall approve (each such date being referred to
herein as a "Quarterly Dividend Payment Date"), commencing on the first
Quarterly Dividend Payment Date after the first issuance of a share or a
fraction of a share of Series A Preferred Stock, in the amount of $1.00 per
whole share (rounded to the nearest cent) less the amount of all cash dividends
declared on the Series A Preferred Stock pursuant to the following clause (2)
since the immediately preceding Quarterly Dividend Payment Date or, with respect
to the first Quarterly Dividend Payment Date, since the first issuance of any
share or fraction of a share of Series A Preferred Stock (the total of which
shall not, in any event, be less than zero) and (2) dividends payable in cash on
the payment date for each cash dividend declared on the Common Stock in an
amount per whole share (rounded to 

                                 Page 58 of 80
<PAGE>
 
the nearest cent) equal to the Formula Number (as hereinafter defined) then in
effect times the cash dividends then to be paid on each share of Common Stock.
In addition, if the Corporation shall pay any dividend or make any distribution
on the Common Stock payable in assets, securities or other forms of noncash
consideration (other than dividends or distributions solely in shares of Common
Stock), then, in each such case, the Corporation shall simultaneously pay or
make on each outstanding whole share of Series A Preferred Stock a dividend or
distribution in like kind equal to the Formula Number then in effect times such
dividend or distribution on each share of the Common Stock. As used herein, the
"Formula Number" shall be 100; provided, however, that, if at any time after
May 19, 1995 the Corporation shall (i) declare or pay any dividend on the Common
Stock payable in shares of Common Stock or make any distribution on the Common
Stock in shares of Common Stock, (ii) subdivide (by a stock split or otherwise)
the outstanding shares of Common Stock into a larger number of shares of Common
Stock or (iii) combine (by a reverse stock split or otherwise) the outstanding
shares of Common Stock into a smaller number of shares of Common Stock, then in
each such event the Formula Number shall be adjusted to a number determined by
multiplying the Formula Number in effect immediately prior to such event by a
fraction, the numerator of which is the number of shares of Common Stock that
are outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that are outstanding immediately prior to such
event (and rounding the result to the nearest whole number); and provided
further, that, if at any time after May 19, 1995, the Corporation shall issue
any shares of its capital stock in a merger, reclassification, or change of the
outstanding shares of Common Stock, then in each such event the Formula Number
shall be appropriately adjusted to reflect such merger, reclassification or
change so that each share of Preferred Stock continues to be the economic
equivalent of a Formula Number of shares of Common Stock prior to such merger,
reclassification or change.

          (b) The Corporation shall declare a dividend or distribution on the
Series A Preferred Stock as provided in Section 2(a) immediately prior to or at
the same time it declares a dividend or distribution on the Common Stock

                                 Page 59 of 80
<PAGE>
 
(other than a dividend or distribution solely in shares of Common Stock);
provided, however, that, in the event no dividend or distribution (other than a
dividend or distribution in shares of Common Stock) shall have been declared on
the Common Stock during the period between any Quarterly Dividend Payment Date
and the next subsequent Quarterly Dividend Payment Date, a dividend of $1.00 per
share on the Series A Preferred Stock shall nevertheless be payable on such
subsequent Quarterly Dividend Payment Date. The Board of Directors may fix a
record date for the determination of holders of shares of Series A Preferred
Stock entitled to receive a dividend or distribution declared thereon, which
record date shall be the same as the record date for any corresponding dividend
or distribution on the Common Stock.

          (c) Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Preferred Stock from and after the Quarterly Dividend Payment
Date next preceding the date of original issue of such shares of Series A
Preferred Stock; provided, however, that dividends on such shares which are
originally issued after the record date for the determination of holders of
shares of Series A Preferred Stock entitled to receive a quarterly dividend and
on or prior to the next succeeding Quarterly Dividend Payment Date shall begin
to accrue and be cumulative from and after such Quarterly Dividend Payment Date.
Notwithstanding the foregoing, dividends on shares of Series A Preferred Stock
which are originally issued prior to the record date for the determination of
holders of shares of Series A Preferred Stock entitled to receive a quarterly
dividend on the first Quarterly Dividend Payment Date shall be calculated as if
cumulative from and after the last day of the fiscal quarter next preceding the
date of original issuance of such shares. Accrued but unpaid dividends shall not
bear interest. Dividends paid on the shares of Series A Preferred Stock in an
amount less than the total amount of such dividends at the time accrued and
payable on such shares shall be allocated pro rata on a share-by-share basis
among all such shares at the time outstanding.

          (d) So long as any shares of the Series A Preferred Stock are
outstanding, no dividends or other distributions shall be declared, paid or

                                 Page 60 of 80
<PAGE>
 
distributed, or set aside for payment or distribution, on the Common Stock
unless, in each case, the dividend required by this Section 2 to be declared on
the Series A Preferred Stock shall have been declared.

          (e) The holders of the shares of Series A Preferred Stock shall not be
entitled to receive any dividends or other distributions except as provided
herein.

          SECTION 3.  VOTING RIGHTS.  The holders of shares of Series A
Preferred Stock shall have the following voting riqhts:

          (a) Each holder of Series A Preferred Stock shall be entitled to a
number of votes equal to the Formula Number then in effect, for each share of
Series A Preferred Stock held of record on each matter on which holders of the
Common Stock or stockholders generally are entitled to vote, multiplied by the
maximum number of votes per share which any holder of the Common Stock or
stockholders generally then have with respect to such matter (assuming any
holding period or other requirement to vote a greater number of shares is
satisfied).

          (b) Except as otherwise provided herein or by applicable law, the
holders of shares of Series A Preferred Stock and the holders of shares of
Common Stock shall vote together as one class for the election of directors of
the Corporation and on all other matters submitted to a vote of stockholders of
the Corporation.

          (c) Except as provided herein, in Section 11 or by applicable law,
holders of Series A Preferred Stock shall have no special voting rights and
their consent shall not be required (except to the extent they are entitled to
vote with holders of Common Stock as set forth herein) for authorizing or taking
any corporate action.

          SECTION 4.  CERTAIN RESTRICTIONS.  (a) Whenever quarterly dividends or
other dividends or distributions payable on the Series A 

                                 Page 61 of 80
<PAGE>
 
Preferred Stock as provided in Section 2 are in arrears, thereafter and until
all accrued and unpaid dividends and distributions, whether or not declared, on
shares of Series A Preferred Stock outstanding shall have been paid in full, the
Corporation shall not

          (i) declare or pay dividends on, make any other distributions on, or
     redeem or purchase or otherwise acquire for consideration any shares of
     stock ranking junior (either as to dividends or upon liquidation,
     dissolution or winding up) to the Series A Preferred Stock;

          (ii) declare or pay dividends on or make any other distributions on
     any shares of stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Preferred Stock,
     except dividends paid ratably on the Series A Preferred Stock and all such
     parity stock on which dividends are payable or in arrears in proportion to
     the total amounts to which the holders of all such shares are then
     entitled;

          (iii) redeem or purchase or otherwise acquire for consideration shares
     of any stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Preferred Stock;
     provided that the Corporation may at any time redeem, purchase or otherwise
     acquire shares of any such parity stock in exchange for shares of any stock
     of the Corporation ranking junior (either as to dividends or upon
     dissolution, liquidation or winding up) to the Series A Preferred Stock; or

          (iv) purchase or otherwise acquire for consideration any shares of
     Series A Preferred Stock, or any shares of stock ranking on a parity with
     the Series A Preferred Stock, except in accordance with a purchase offer
     made in writing or by publication (as determined by the Board of Directors)
     to all holders of such shares upon such terms as the Board of Directors,
     after consideration of the respective annual dividend rates and other
     relative rights and preferences of the respective series and

                                 Page 62 of 80
<PAGE>
 
     classes, shall determine in good faith will result in fair and equitable
     treatment among the respective series or classes.

          (b) The Corporation shall not permit any subsidiary of the Corporation
to purchase or otherwise acquire for consideration any shares of stock of the
Corporation unless the Corporation could, under paragraph (a) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

          SECTION 5.  LIQUIDATION RIGHTS.  Upon the liquidation, dissolution or
winding up of the Corporation, whether voluntary or involuntary, no distribution
shall be made (1) to the holders of shares of stock ranking junior (either as to
dividends or upon liquidation, dissolution or winding up) to the Series A
Preferred Stock unless prior thereto, the holders of shares of Series A
Preferred Stock shall have received an amount equal to the accrued and unpaid
dividends and distributions thereon, whether or not declared, to the date of
such payment, plus an amount equal to the greater of (x) $1.00 per whole share
or (y) an aggregate amount per share equal to the Formula Number then in effect
times the aggregate amount to be distributed per share to holders of Common
Stock or (2) to the holders of stock ranking on a parity (either as to dividends
or upon liquidation, dissolution or winding up) with the Series A Preferred
Stock, except distributions made ratably on the Series A Preferred Stock and all
other such parity stock in proportion to the total amounts to which the holders
of all such shares are entitled upon such liquidation, dissolution or winding
up.

          SECTION 6.  CONSOLIDATION, MERGER, ETC.  In case the Corporation shall
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash or any other property, then in any such case the then
outstanding shares of Series A Preferred Stock shall at the same time be
similarly exchanged or changed into an amount per share equal to the Formula
Number then in effect times the aggregate amount of stock, securities, cash or
any other property (payable in kind), as the case may be, into which or for

                                 Page 63 of 80
<PAGE>
 
which each share of Common Stock is exchanged or changed.  In the event both
this Section 6 and Section 2 appear to apply to a transaction, this Section 6
will control.

          SECTION 7.  NO REDEMPTION; NO SINKING FUND.  (a) The shares of Series
A Preferred Stock shall not be subject to redemption by the Corporation or at
the option of any holder of Series A Preferred Stock; provided, however, that
the Corporation may purchase or otherwise acquire outstanding shares of Series A
Preferred Stock in the open market or by offer to any holder or holders of
shares of Series A Preferred Stock.

          (b) The shares of Series A Preferred Stock shall not be subject to or
entitled to the operation of a retirement or sinking fund.

          SECTION 8.  RANKING. The Series A Preferred Stock shall rank junior to
all other series of Preferred Stock of the Corporation, unless the Board of
Directors shall specifically determine otherwise in fixing the powers,
preferences and relative, participating, optional and other special rights of
the shares of such series and the qualifications, limitations and restrictions
thereof.

          SECTION 9.  FRACTIONAL SHARES.  The Series A Preferred Stock shall be
issuable upon exercise of the Rights issued pursuant to the Rights Agreement in
whole shares or in any fraction of a share that is one one-hundredth (1/100th)
of a share or any integral multiple of such fraction which shall entitle the
holder, in proportion to such holder's fractional shares, to receive dividends,
exercise voting rights, participate in distributions and to have the benefit of
all other rights of holders of Series A Preferred Stock.  In lieu of fractional
shares, the Corporation, prior to the first issuance of a share or a fraction of
a share of Series A Preferred Stock, may elect (1) to make a cash payment as
provided in the Rights Agreement for fractions of a share other than one one-
hundredth (1/100th) of a share or any integral multiple thereof or (2) to issue
depository receipts evidencing such 

                                 Page 64 of 80
<PAGE>
 
authorized fraction of a share of Series A Preferred Stock pursuant to an
appropriate agreement between the Corporation and a depository selected by the
Corporation; provided that such agreement shall provide that the holders of such
depository receipts shall have all the rights, privileges and preferences to
which they are entitled as holders of the Series A Preferred Stock.

          SECTION 10.  REACQUIRED SHARES.  Any shares of Series A Preferred
Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and canceled promptly after the acquisition thereof.
All such shares shall upon their cancellation become authorized but unissued
shares of Preferred Stock, without designation as to series until such shares
are once more designated as part of a particular series by the Board of
Directors pursuant to the provisions of Section 2 of Article IV of the
Certificate of Incorporation.

          SECTION 11.  AMENDMENT.  None of the powers, preferences and relative,
participating, optional and other special rights of the Series A Preferred Stock
as provided herein or in the Certificate of Incorporation shall be amended in
any manner which would alter or change the powers, preferences, rights or
privileges of the holders of Series A Preferred Stock so as to affect them
adversely without the affirmative vote of the holders of at least 66-2/3% of the
outstanding shares of Series A Preferred Stock, voting as a separate class;
provided, however, that no such amendment approved by the holders of at least
66-2/3% of the outstanding shares of Series A Preferred Stock shall be deemed to
apply to the powers, preferences, rights or privileges of any holder of shares
of Series A Preferred Stock originally issued upon exercise of the Rights after
the time of such approval without the approval of such holder.

                                 Page 65 of 80
<PAGE>
 
          IN WITNESS WHEREOF, the Corporation has caused this Certificate to be
duly executed in its corporate name as of the 19th day of May, 1995.


                                    UNIT CORPORATION



                                    by     /s/ John G. Nikkel
                                      -----------------------
                                         By:  John G. Nikkel
                                         Its: President

Attest:


by     /s/ Mark E. Schell
  -----------------------
     By:  Mark E. Schell
     Its: Secretary

                                 Page 66 of 80

<PAGE>
 
                                                                    EXHIBIT 1(B)
                          [Form of Right Certificate]


Certificate No. [R]-
          _______________ Rights


          NOT EXERCISABLE AFTER MAY 19, 2005, OR EARLIER IF REDEEMED BY THE
          COMPANY.  THE RIGHTS ARE SUBJECT TO REDEMPTION, AT THE OPTION OF THE
          COMPANY, AT $.01 PER RIGHT, ON THE TERMS SET FORTH IN THE RIGHTS
          AGREEMENT.  RIGHTS BENEFICIALLY OWNED BY AN ACQUIRING PERSON OR AN
          AFFILIATE OR ASSOCIATE OF AN ACQUIRING PERSON (AS SUCH TERMS ARE
          DEFINED IN THE RIGHTS AGREEMENT) AND BY ANY SUBSEQUENT HOLDER OF SUCH
          RIGHTS ARE NULL AND VOID AND NONTRANSFERABLE.


                               Right Certificate

                               UNIT CORPORATION


          This certifies that                     , or registered assigns, is
the registered owner of the number of Rights set forth above, each of which
entitles the owner thereof, subject to the terms, provisions and conditions of
the Rights Agreement dated as of May 19, 1995 (the "Rights Agreement"), between
Unit Corporation, a Delaware corporation (the "Company"), and Chemical Bank, a
New York banking corporation, as Rights Agent (the "Rights Agent"), unless the
Rights evidenced hereby shall have been previously redeemed by the Company, to
purchase from the Company at any time after the Distribution Date (as defined in
the Rights Agreement) and prior to 5:00 p.m., New York City time, on the 10th
anniversary of the date of the Rights Agreement (the "Expiration Date"), at the
principal office of the Rights Agent, or its successors as Rights Agent; in the
City of New York, one one-hundredth (1/100th) of a fully paid, nonassessable
share of Series A Participating Cumulative Preferred Stock, par value $1.00 per
share, of the Company (the "Preferred Shares"), at a purchase price per one one-
hundredth (1/100th) of a share equal to $12.75 (the "Purchase Price") payable in
cash, upon presentation and surrender of this Right Certificate with the Form of
Election to Purchase duly executed.

                                 Page 67 of 80
<PAGE>
 
          The Purchase Price and the number and kind of shares which may be
purchased upon exercise of each Right evidenced by this Right Certificate, as
set forth above, are the Purchase Price and the number and kind of shares which
may be so purchased as of [            ].  As provided in the Rights Agreement,
the Purchase Price and the number and kind of shares which may be purchased upon
the exercise of each Right evidenced by this Right Certificate are subject to
modification and adjustment upon the happening of certain events.

          If the Rights evidenced by this Right Certificate are at any time
beneficially owned by an Acquiring Person or an Affiliate or Associate of an
Acquiring Person (as such terms are defined in the Rights Agreement), such
Rights shall be null and void and nontransferable and the holder of any such
Right (including any purported transferee or subsequent holder) shall not have
any right to exercise or transfer any such Right.

          This Right Certificate is subject to all the terms, provisions and
conditions of the Rights Agreement, which terms, provisions and conditions are
hereby incorporated herein by reference and made a part hereof and to which
reference to the Rights Agreement is hereby made for a full description of the
rights, limitations of rights, obligations, duties and immunities hereunder of
the Rights Agent, the Company and the holders of the Right Certificates.  Copies
of the Rights Agreement are on file at the above-mentioned office of the Rights
Agent and are also available from the Company upon written request.

          This Right Certificate, with or without other Right Certificates, upon
surrender at the principal stock transfer or corporate trust office of the
Rights Agent, may be exchanged for another Right Certificate or Right
Certificates of like tenor and date evidencing Rights entitling the holder to
purchase a like aggregate number and kind of shares as the Rights evidenced by
the Right Certificate or Right Certificates surrendered shall have entitled such
holder to purchase.  If this Right Certificate shall be exercised in part, the
holder shall be entitled to receive upon surrender hereof another 

                                 Page 68 of 80
<PAGE>
 
Right Certificate or Right Certificates for the number of whole Rights not
exercised.

          Subject to the provisions of the Rights Agreement, the Rights
evidenced by this Right Certificate may be redeemed by the Company at its option
at a redemption price (in cash or shares of Common Stock or other securities of
the Company deemed by the Board of Directors to be at least equivalent in value)
of $.01 per Right (which amount shall be subject to adjustment as provided in
the Rights Agreement) at any time prior to the earlier of (i) the close of
business on the tenth day following the time the Company learns that a Person
has become an Acquiring Person and (ii) the Expiration Date; provided, however,
that, for the 120-day period after any date of a change (resulting from a proxy
or consent solicitation) in a majority of the Board of Directors of the Company
in office at the commencement of such solicitation, the Rights may only be
redeemed if (A) there are directors then in office who were in office at the
commencement of such solicitation and (B) the Board of Directors of the Company,
with the concurrence of a majority of such directors then in office, determines
that such redemption is, in their judgment, in the best interests of the Company
and its stockholders.

          The Company may, but shall not be required to, issue fractions of
Preferred Shares or distribute certificates which evidence fractions of
Preferred Shares upon the exercise of any Right or Rights evidenced hereby.  In
lieu of issuing fractional shares, the Company may elect to make a cash payment
as provided in the Rights Agreement for fractions of a share other than one one-
hundredth (1/100th) of a share or any integral multiple thereof or to issue
certificates or utilize a depository arrangement as provided in the terms of the
Rights Agreement and the Preferred Shares.

          No holder of this Right Certificate shall be entitled to vote or
receive dividends or be deemed for any purpose the holder of the Preferred
Shares or of any other securities of the Company which may at any time be
issuable on the exercise hereof, nor shall anything contained in the Rights

                                 Page 69 of 80
<PAGE>
 
Agreement or herein be construed to confer upon the holder hereof, as such, any
of the rights of a stockholder of the Company, including, without limitation,
any right to vote for the election of directors or upon any matter submitted to
stockholders at any meeting thereof, or to give or withhold consent to any
corporate action; or to receive notice of meetings or other actions affecting
stockholders (except as provided in the Rights Agreement), or to receive
dividends or other distributions or subscription rights, or otherwise, until the
Right or Rights evidenced by this Right Certificate shall have been exercised as
provided in accordance with the provisions of the Rights Agreement.

          This Right Certificate shall not be valid or obligatory for any
purpose until it shall have been countersigned by the Rights Agent.


          WITNESS the facsimile signature of the proper officers of the Company
and its corporate seal.

Dated as of: ___________________

                                    UNIT CORPORATION

                                    by ________________________
                                         Name:  John G. Nikkel
                                         Title: President
Attest:


by_________________________
     Name:  Mark E. Schell
     Title: Secretary

Countersigned:

CHEMICAL BANK,
as Rights Agent,


     by ________________________
          Authorized Officer

                                 Page 70 of 80
<PAGE>
 
                     [On Reverse Side of Right Certificate]


                         FORM OF ELECTION TO PURCHASE

                  (To be executed by the registered holder if
                  such holder desires to exercise the Rights
                    represented by this Right Certificate.)


To the Rights Agent:
          The undersigned hereby irrevocably elects to
exercise                 Rights represented by this Right
Certificate to purchase the Preferred Shares (or other
shares) issuable upon the exercise of such Rights and
requests that certificates for such shares be issued in the
name of:

Please insert social security
or other identifying number

------------------------------------------------------------
                        (Please print name and address)
------------------------------------------------------------

          If such number of Rights shall not be all the Rights evidenced by this
Right Certificate, a new Right Certificate for the balance remaining of such
Rights shall be registered in the name of and delivered to:

Please insert social security
or other identifying number

------------------------------------------------------------
                        (Please print name and address)
------------------------------------------------------------

Dated:_______________,19__

                                 Page 71 of 80
<PAGE>
 
                                    _________________________
                                    Signature

Signature Guaranteed:

                                 Page 72 of 80
<PAGE>
 
                                     NOTICE

          The signature on the foregoing Form of Election to Purchase must
correspond to the name as written upon the face of this Right Certificate in
every particular, without  alteration or enlargement or any change whatsoever.

                                 Page 73 of 80

<PAGE>
 
                                                                    EXHIBIT 1(C)

                 SUMMARY OF RIGHTS TO PURCHASE PREFERRED STOCK

     As of May 19, 1995, the Board of Directors of Unit Corporation (the
"COMPANY") declared a dividend of one preferred stock purchase right (Right) 
for each outstanding share of Common stock, par value $0.20 per share, of the 
Company (the "COMMON SHARES").  The Rights will be issued to the holders of 
record of Common Shares outstanding on May   , 1995, and with respect to Common
Shares issued thereafter until the Distribution Date (as defined below) and, 
in certain circumstances, with respect to Common Shares issued after the 
Distribution Date.  Each Right, when it becomes exercisable as described below,
will entitle the registered holder to purchase from the Company one 
one-hundredth (1/100th) of a share of Series A Participating Cumulative 
Preferred Stock, par value $1.00 per share, of the company (the "PREFERRED 
SHARES") at a price of $12.75 (the "PURCHASE PRICE").  The description and 
terms of the Rights are set forth in a Rights Agreement dated as of May 19, 
1995 (the "RIGHTS AGREEMENT"), between the Company and Chemical Bank, as 
Rights Agent (the "RIGHTS AGENT").

     Until the earlier of (i) the tenth day after the Company learns that a
person or group (including any affiliate or associate of such person or group)
has acquired, or has obtained the right to acquire, beneficial ownership of more
than 15% of the outstanding Common Shares (such person or group being an
"ACQUIRING PERSON"), and (ii) the tenth Business Day (or such later date as may
be designated by the Board of Directors of the Company) following the

                                 Page 74 of 80
<PAGE>
 
commencement of, or first public disclosure of an intent to commence, a tender
or exchange offer for outstanding Common Shares which could result in such
person or group becoming the beneficial owner of more than 15% of the
outstanding Common Shares (the earlier of such dates being called the
"DISTRIBUTION DATE"), the Rights will be evidenced by the certificates for
Common Shares registered in the names of the holders thereof (which certificates
for Common Shares shall also be deemed to be Right Certificates, as defined
below) and not by separate Right Certificates.  Therefore, until the
Distribution Date, the Rights will be transferred with and only with the Common
Shares.

     As soon as practicable following the Distribution Date, separate
certificates evidencing the Rights ("RIGHT CERTIFICATES") will be mailed to
holders of record of the Common Shares as of the close of business on the
Distribution Date (and to each initial record holder of certain Common Shares
originally issued after the Distribution Date), and such separate Right
Certificates alone will thereafter evidence the Rights.

     The Rights are not exercisable until the Distribution Date and will expire
on May 19, 2005 (the "EXPIRATION DATE") unless earlier redeemed by the Company
as described below.

     The number of Preferred Shares or other securities issuable upon exercise
of a Right, the Purchase Price, the Redemption Price (as defined below) and the
number of Rights associated with each outstanding Common Share are all subject
to adjustment by the Board of Directors of the Company in the event of any
change in the Common Shares or the Preferred Shares, whether by reason of stock
dividends, stock splits, recapitalization, mergers, 

                                 Page 75 of 80
<PAGE>
 
consolidations, combinations or exchanges of securities, split-ups, split-offs,
spin-offs, liquidations, other similar changes in capitalization, any
distribution or issuance of cash, assets, evidences of indebtedness or
subscription rights, options or warrants to holder of Common Shares or Preferred
Shares, as the case may be (other than distribution of the Rights or regular
quarterly cash dividends) or otherwise.

     The Preferred Shares are authorized to be issued in fractions which are an
integral multiple of one one-hundredth (1/100th) of a Preferred Share.  The
Company may, but is not required to, issue fractions of shares upon the exercise
of Rights, and, in lieu of fractional shares, the Company may issue certificates
or utilize a depository arrangement as provided by the terms of the Preferred
Shares and, in the case of fractions other than one one-hundredth (1/100th) of a
Preferred Share or integral multiples thereof, may make a cash payment based on
the market price of such shares.

     At such time there is an Acquiring Person, the Rights will entitle each
holder (other than such Acquiring Person (or any affiliate or associate of such
Acquiring Person)) of a Right to purchase, for the Purchase Price, that number
of one one-hundredths (1/100th) of a Preferred Share equivalent to the number of
Common Shares which at the time of such event would have a market value of twice
the Purchase Price.

     In the event the Company is acquired in a merger or other business
combination by an Acquiring Person or an associate or affiliate of an Acquiring
Person that is a publicly traded corporation or 50% or more of the Company's
assets or assets representing 50% or more of the Company's revenues or cash flow
are sold, leased, exchanged or otherwise transferred (in one or 

                                 Page 76 of 80
<PAGE>
 
more transactions) to an Acquiring Person or an associate or affiliate of an
Acquiring Person that is a publicly traded corporation, each Right will entitle
its holder (subject to the next paragraph) to purchase, for the Purchase Price,
that number of common shares of such corporation which at the time of the
transaction would have a market value of twice the Purchase Price. In the event
the Company is acquired in a merger or other business combination by an
Acquiring Person or an associate or affiliate of an Acquiring Person that is not
a publicly traded entity or 50% or more of the Company's assets or assets
representing 50% or more of the Company's revenues or cash flow are sold,
leased, exchanged or otherwise transferred (in one or more transactions) to an
Acquiring Person or an associate or affiliate of an Acquiring Person that is not
a publicly traded entity, each Right will entitle its holder (subject to the
next paragraph) to purchase, for the Purchase Price, at such holder's option,
(i) that number of shares of the surviving corporation in the transaction with
such entity (which surviving corporation could be the Company) which at the time
of the transaction would have a book value of twice the Purchase Price, (ii)
that number of shares of such entity which at the time of the transaction would
have a book value of twice the Purchase Price or (iii) if such entity has an
affiliate which has publicly traded common shares, that number of common shares
of such affiliate which at the time of the transaction would have a market value
of twice the Purchase Price.

     Any Rights that are, at any time beneficially owned by an Acquiring Person
(or any affiliate or associate of an Acquiring Person) will be null and void and
nontransferable and any holder of any such Right (including any 

                                 Page 77 of 80
<PAGE>
 
purported transferee or subsequent holder) will be unable to exercise or
transfer any such Right.

     At any time prior to the earlier of (i) the close of business on the tenth
day following the time the Company learns that a Person has become an Acquiring
person and (ii) the Expiration Date, the Board of Directors of the Company may
redeem the Rights in whole, but not in part, at a price (in cash or Common
Shares or other securities of the Company deemed by the Board of Directors to be
at least equivalent in value) of $.01 per Right, subject to adjustment as
provided in the Rights Agreement (the "REDEMPTION DATE"); provided, however,
that, for the 120-day period after any date of a change (resulting from a proxy
or consent solicitation) in a majority of the Board of Directors of the Company
in office at the commencement of such solicitation, the Rights may only be
redeemed if (A) there are directions then in office who were in office at the
commencement of such solicitation and (B) the Board of Directors of the Company,
with concurrence of a majority of such directors then in office, determines that
such redemption is, in their judgment, in the best interests of the Company and
its stockholders.

     Immediately upon the action of the Board of Directors of the Company
electing to redeem the Rights, and without any further action and without any
notice, the right to exercise the Rights will terminate and the only right of
the holders of Rights will be to receive the Redemption Price.

     After there is an Acquiring Person, the Board of Directors may elect to
exchange each Right (other than Rights that shall have become null and void and
nontransferable as described above) for consideration per Right consisting 

                                 Page 78 of 80
<PAGE>
 
of one-half of the securities that would be issuable at such time upon the
exercise of one Right pursuant to the terms of the Rights Agreement.

     Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the company, including, without limitation, the right
to vote or to receive dividends.

     At any time prior to the Distribution Date, the Company may, without the
approval of any holder of the Rights, supplement or amend any provision of the
Rights Agreement (including the date on which the Distribution Date shall occur,
the time during which the Rights may be redeemed or the terms of the Preferred
Shares), except that no supplement or amendment shall be made which reduces the
Redemption Price (other than pursuant to certain adjustments therein) or
provides for an earlier Expiration Date.  Without limiting the foregoing, the
Company may at any time prior to such time as a person becomes an Acquiring
Person amend this Agreement to (a) specifically exempt any person from being or
being deemed to be an Acquiring Person, subject to such terms and conditions as
the Company deems appropriate, (b) fix an Expiration Date later than the date
set forth in the Rights Agreement or (c) increase the Purchase Price.  However,
during the 120-day period after any date of a change (resulting from a proxy or
consent solicitation) in a majority of the Board of Directors of the Company in
office at the commencement of such solicitation, the Rights Agreement may be
supplemented or amended only if (A) there are directors then in office who were
in office at the commencement of such solicitation and (B) the Board of
Directors of the Company, with the concurrence of a majority of such directors
then in office, determines that 

                                 Page 79 of 80
<PAGE>
 
such supplement or amendment is, in their judgment, in the best interests of the
Company and its stockholders.

     Preferred Shares purchasable upon exercise of the Rights will not be
redeemable. Each Preferred Share will be entitled to a minimum preferential
quarterly dividend payment of $1.00 per share but will be entitled to an
aggregate dividend of 100 times the dividend declared per Common Share. In the
event of liquidation, the holders of the Preferred Shares will be entitled to a
minimum preferential liquidation payment of $100 per share but will be entitled
to an aggregate payment of 100 times the payment made per Common Share. Each
Preferred Share will have 100 votes, voting together with the Common Shares.
Finally, in the event of any merger, consolidation or other transaction in which
Common Shares are exchanged, each Preferred Share will be entitled to receive
100 times the amount received per Common Share. These rights are protected by
customary antidilution provisions.

     The Rights have certain antitakeover effects.  The Rights will cause
substantial dilution to a person or group that attempts to acquire the Company
without conditioning the offer on substantially all the Rights being acquired.
The Rights will not interfere with any merger or other business combination with
a third party approved by the Board of Directors of the Company since the Board
of Directors of the Company may, at its option, at any time prior to any person
becoming an Acquiring Person exempt such Person from being deemed an Acquiring
Person or redeem all, but not less than all, of the then outstanding Rights at
the Redemption Price.

     The foregoing description of the Rights does not purport to be complete and
is qualified in its entirety by reference to the Rights Agreement, the
Certificate of Designation of the Preferred Shares (Exhibit A to the Rights
Agreement) and the form of Right Certificate (Exhibit B to the Rights Agreement)
all of which are incorporated herein by reference.  A copy of the Rights
Agreement has been filed with the Securities and Exchange Commission as an
exhibit to a Registration Statement on Form 8-A.  A copy of the Rights Agreement
is available free of charge from the Company.

                                 Page 80 of 80



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