Document:

<PAGE>
                                                                    Exhibit 4.1

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

                              GILEAD SCIENCES, INC.

                                       and

                     CHASE MANHATTAN BANK AND TRUST COMPANY,
                              NATIONAL ASSOCIATION
                                       as
                                     Trustee

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

                                    INDENTURE

                          Dated as of December 18, 2000

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

                         $250,000,000 Principal Amount(a)

                   5% CONVERTIBLE SUBORDINATED NOTES DUE 2007

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

-----------------------------
(a) Plus an additional $50,000,000 issuable at the option of the Initial
    Purchasers as described herein.

<PAGE>

                              CROSS-REFERENCE TABLE
<TABLE>
<CAPTION>
  TIA                                                                                    Indenture
Section                                                                                   Section
-------                                                                                 -----------
<S>                                                                                     <C>

310(a)(1)...........................................................................       7.10
   (a)(2)...........................................................................       7.10
   (a)(3)...........................................................................       N.A.
   (a)(4)...........................................................................       N.A.
   (a)(5)...........................................................................       N.A.
   (b)..............................................................................       7.08; 7.10; 13.02
   (c)..............................................................................       N.A.
311(a)..............................................................................       7.11
   (b)..............................................................................       7.11
   (c)..............................................................................       N.A.
312(a)..............................................................................       2.05
   (b)..............................................................................       13.03
   (c)..............................................................................       13.03
313(a)..............................................................................       7.06
   (b)(1)...........................................................................       N.A.
   (b)(2)...........................................................................       7.06
   (c)..............................................................................       7.06; 13.02
   (d)..............................................................................       7.06
314(a)..............................................................................       4.02
   (b)..............................................................................       N.A.
   (c)(1)...........................................................................       13.04
   (c)(2)...........................................................................       13.04
   (c)(3)...........................................................................       N.A.
   (d)..............................................................................       N.A.
   (e)..............................................................................       13.05
   (f)..............................................................................       N.A.
315(a)..............................................................................       7.01(b)
   (b)..............................................................................       7.05; 13.02
   (c)..............................................................................       7.01(a)
   (d)..............................................................................       7.01(c)
   (e)..............................................................................       6.11
316(a)(last sentence)...............................................................       2.09
   (a)(1)(A)........................................................................       6.05
   (a)(1)(B)........................................................................       6.04
   (a)(2)...........................................................................       N.A.
   (b)..............................................................................       6.07
317(a)(1)...........................................................................       6.08
   (a)(2)...........................................................................       6.09
   (b)..............................................................................       2.04
318(a)..............................................................................       13.01

</TABLE>
<PAGE>

                                TABLE OF CONTENTS
<TABLE>
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                                   ARTICLE ONE

                   DEFINITIONS AND INCORPORATION BY REFERENCE

SECTION 1.01.         Definitions.............................................................................1
SECTION 1.02.         Other Definitions.......................................................................5
SECTION 1.03.         Incorporation by Reference of Trust Indenture Act.......................................6
SECTION 1.04.         Rules of Construction...................................................................6

                                   ARTICLE TWO

                                 THE SECURITIES

SECTION 2.01.         Form and Dating.........................................................................7
SECTION 2.02.         Execution and Authentication............................................................7
SECTION 2.03.         Registrar, Paying Agent and Conversion Agent............................................8
SECTION 2.04.         Paying Agent to Hold Money in Trust.....................................................8
SECTION 2.05.         Securityholder Lists....................................................................9
SECTION 2.06.         Transfer and Exchange...................................................................9
SECTION 2.07.         Replacement Securities..................................................................9
SECTION 2.08.         Outstanding Securities.................................................................10
SECTION 2.09.         Securities Held by the Company or an Affiliate.........................................10
SECTION 2.10.         Temporary Securities...................................................................10
SECTION 2.11.         Cancellation...........................................................................10
SECTION 2.12.         Defaulted Interest.....................................................................11
SECTION 2.13.         CUSIP Numbers..........................................................................11
SECTION 2.14.         Deposit of Moneys......................................................................11
SECTION 2.15.         Book-Entry Provisions for Global Securities............................................11
SECTION 2.16.         Special Transfer Provisions............................................................12
SECTION 2.17.         Restrictive Legends....................................................................15

                                  ARTICLE THREE

                             REDEMPTION; REPURCHASE

SECTION 3.01.         Notices to Trustee.....................................................................15
SECTION 3.02.         Selection of Securities to Be Redeemed.................................................16
SECTION 3.03.         Notice of Redemption...................................................................16
SECTION 3.04.         Effect of Notice of Redemption.........................................................17
SECTION 3.05.         Deposit of Redemption Price............................................................17
SECTION 3.06.         Securities Redeemed in Part............................................................17
SECTION 3.07.         Repurchase at Option of Holder upon a Repurchase Event.................................17
</TABLE>

                                      -i-
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<TABLE>
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                                  ARTICLE FOUR

                                    COVENANTS

SECTION 4.01.         Payment of Securities..................................................................22
SECTION 4.02.         Maintenance of Office or Agency........................................................23
SECTION 4.03.         Reports to Holders.....................................................................23
SECTION 4.04.         Compliance Certificate.................................................................23
SECTION 4.05.         Stay, Extension and Usury Laws.........................................................24
SECTION 4.06.         Corporate Existence....................................................................24
SECTION 4.07.         Notice of Default......................................................................24

                                  ARTICLE FIVE

                    CONSOLIDATION, MERGER AND SALE OF ASSETS

SECTION 5.01.         When Company May Merge, etc............................................................24
SECTION 5.02.         Successor Substituted..................................................................25

                                   ARTICLE SIX

                              DEFAULTS AND REMEDIES

SECTION 6.01.         Events of Default......................................................................25
SECTION 6.02.         Acceleration...........................................................................26
SECTION 6.03.         Other Remedies.........................................................................27
SECTION 6.04.         Waiver of Past Defaults................................................................27
SECTION 6.05.         Control by Majority....................................................................27
SECTION 6.06.         Limitation on Suits....................................................................27
SECTION 6.07.         Rights of Holders to Receive Payment or Convert........................................28
SECTION 6.08.         Collection Suit by Trustee.............................................................28
SECTION 6.09.         Trustee May File Proofs of Claim.......................................................28
SECTION 6.10.         Priorities.............................................................................28
SECTION 6.11.         Undertaking for Costs..................................................................29

                                  ARTICLE SEVEN

                                     TRUSTEE

SECTION 7.01.         Duties of Trustee......................................................................29
SECTION 7.02.         Rights of Trustee......................................................................30
SECTION 7.03.         Individual Rights of Trustee...........................................................31
SECTION 7.04.         Trustee's Disclaimer...................................................................31
SECTION 7.05.         Notice of Defaults.....................................................................32
SECTION 7.06.         Reports by Trustee to Holders..........................................................32
SECTION 7.07.         Compensation and Indemnity.............................................................32
SECTION 7.08.         Replacement of Trustee.................................................................33
</TABLE>

                                      -ii-
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<TABLE>
<CAPTION>
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<S>                                                                                                          <C>
SECTION 7.09.         Successor Trustee by Merger, etc.......................................................34
SECTION 7.10.         Eligibility; Disqualification..........................................................34
SECTION 7.11.         Preferential Collection of Claims Against Company......................................34

                                  ARTICLE EIGHT

                     SATISFACTION AND DISCHARGE; DEFEASANCE

SECTION 8.01.         Termination of Company's Obligations...................................................34
SECTION 8.02.         Application of Trust Money.............................................................35
SECTION 8.03.         Repayment to Company...................................................................36
SECTION 8.04.         Reinstatement..........................................................................36

                                  ARTICLE NINE

                                   AMENDMENTS

SECTION 9.01.         Without Consent of Holders.............................................................36
SECTION 9.02.         With Consent of Holders................................................................37
SECTION 9.03.         Compliance with Trust Indenture Act....................................................37
SECTION 9.04.         Revocation and Effect of Consents......................................................38
SECTION 9.05.         Notation on or Exchange of Securities..................................................38
SECTION 9.06.         Trustee Protected......................................................................38

                                   ARTICLE TEN

                                   CONVERSION

SECTION 10.01.        Conversion Privilege; Restrictive Legends..............................................38
SECTION 10.02.        Conversion Procedure...................................................................39
SECTION 10.03.        Fractional Shares......................................................................40
SECTION 10.04.        Taxes on Conversion....................................................................40
SECTION 10.05.        Company to Provide Stock...............................................................40
SECTION 10.06.        Adjustment of Conversion Price.........................................................40
SECTION 10.07.        Effect of Reclassification, Consolidation, Merger or Sale..............................49
SECTION 10.08.        Notice of Certain Transactions.........................................................50
SECTION 10.09.        Company Determination Final............................................................50
SECTION 10.10.        Trustee's Disclaimer...................................................................50
</TABLE>

                                      -iii-
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<TABLE>
<CAPTION>
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<S>                                                                                                          <C>
                                 ARTICLE ELEVEN

                                   [RESERVED]

                                 ARTICLE TWELVE

                                  SUBORDINATION

SECTION 12.01.        Securities Subordinated to Senior Indebtedness.........................................51
SECTION 12.02.        Subrogation............................................................................53
SECTION 12.03.        Obligation of Company Unconditional....................................................53
SECTION 12.04.        Modification of Terms of Senior Indebtedness...........................................53
SECTION 12.05.        [Reserved].............................................................................54
SECTION 12.06.        Effectuation of Subordination by Trustee...............................................54
SECTION 12.07.        Knowledge of Trustee...................................................................54
SECTION 12.08.        Trustee's Relation to Senior Indebtedness..............................................55
SECTION 12.09.        Rights of Holders of Senior Indebtedness Not Impaired..................................55
SECTION 12.10.        Certain Conversions Not Deemed Payment.................................................55

                                ARTICLE THIRTEEN

                                  MISCELLANEOUS

SECTION 13.01.        Trust Indenture Act Controls...........................................................56
SECTION 13.02.        Notices................................................................................56
SECTION 13.03.        Communication by Holders with Other Holders............................................57
SECTION 13.04.        Certificate and Opinion as to Conditions Precedent.....................................57
SECTION 13.05.        Statements Required in Certificate or Opinion..........................................57
SECTION 13.06.        Rules by Trustee and Agents............................................................58
SECTION 13.07.        Legal Holidays.........................................................................58
SECTION 13.08.        No Recourse Against Others.............................................................58
SECTION 13.09.        Duplicate Originals....................................................................58
SECTION 13.10.        Governing Law..........................................................................58
SECTION 13.11.        No Adverse Interpretation of Other Agreements..........................................58
SECTION 13.12.        Successors.............................................................................59
SECTION 13.13.        Separability...........................................................................59
SECTION 13.14.        Table of Contents, Headings, etc.......................................................59

SIGNATURES..................................................................................................S-1
</TABLE>

                                      -iv-
<PAGE>

EXHIBITS

Exhibit A   -   Form of Security
Exhibit B   -   Form of Legends
Exhibit C   -   Form of Certificate to Be Delivered in Connection with Transfers
                  to Non-QIB Accredited Investors
Exhibit D   -   Form of Certificate to Be Delivered in Connection with Transfers
                  Pursuant to Regulation S
Exhibit E   -   Form of Notice of Transfer Pursuant to Registration Statement

                                      -v-
<PAGE>

                  INDENTURE dated as of December 18, 2000 between GILEAD
SCIENCES, INC., a Delaware corporation (the "COMPANY"), and CHASE MANHATTAN BANK
AND TRUST COMPANY, NATIONAL ASSOCIATION, as trustee (the "TRUSTEE").

                  Each party agrees as follows for the benefit of the other
party and for the equal and ratable benefit of the Holders of the Company's 5%
Convertible Subordinated Notes Due 2007:

                                   ARTICLE ONE

                   DEFINITIONS AND INCORPORATION BY REFERENCE

SECTION 1.01.         DEFINITIONS.

                  "AFFILIATE" means any Person directly or indirectly
controlling or controlled by or under direct or indirect common control with the
Company. For this purpose, "control" shall mean the power to direct the
management and policies of a Person through the ownership of securities, by
contract or otherwise.

                  "AGENT" means any Registrar, Paying Agent, Conversion Agent
or co-registrar.

                  "BOARD OF DIRECTORS" means the Board of Directors of the
Company or any committee of the Board of Directors authorized to act for it
hereunder.

                  "BOARD RESOLUTION" means a copy of a resolution certified by
the Secretary or an Assistant Secretary of the Company to have been duly adopted
by the Board of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

                  "CAPITAL STOCK" means any and all shares, interests,
participations or other equivalents (however designated) of capital stock of the
Company and all warrants or options to acquire such capital stock.

                  "CLOSE OF BUSINESS" means 5:00 p.m., New York City time.

                  "COMMON STOCK" means the common stock, par value $.001 per
share, of the Company.

                  "COMPANY" means the party named as such above until a
successor replaces it pursuant to the applicable provision hereof and thereafter
means the successor.

                  "COMPANY REQUEST" or "COMPANY ORDER" means a written request
or order signed on behalf of the Company by its Chairman or Co-Chairman of the
Board of Directors, any Vice Chairman of the Board of Directors, its Chief
Executive Officer, its Chief Operating Officer, its Chief Financial Officer, its
Treasurer, its President or any Vice President and by its Treasurer or an
Assistant Treasurer, its Secretary or an Assistant Secretary, and delivered to
the Trustee.

<PAGE>
                                       -2-

                  "CONVERSION PRICE" means $98.25 per share of Common Stock, as
adjusted pursuant to Article Ten.

                  "CORPORATE TRUST OFFICE OF THE TRUSTEE" shall be at the
address of the Trustee specified in Section 13.02 or such other address as the
Trustee may give notice of to the Company.

                  "DEFAULT" means any event which is, or after notice or passage
of time or both would be, an Event of Default.

                  "DEPOSITORY" means The Depository Trust Company, its nominees
and successors.

                  "DESIGNATED SENIOR INDEBTEDNESS" means any Senior Indebtedness
in which the instrument creating or evidencing the same or the assumption or
guarantee thereof (or related agreements or documents to which the Company is a
party) expressly provides that such Senior Indebtedness shall be "Designated
Senior Indebtedness" for purposes of this Indenture.

                  "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

                  "HOLDER" means a Person in whose name a Security is registered
on the Registrar's books.

                  "IAI GLOBAL SECURITY" means a permanent Global Security in
registered form representing the aggregate principal amount of Securities
transferred to Institutional Accredited Investors.

                  "INDEBTEDNESS" means, with respect to any Person, (i) all
obligations, indebtedness and other liabilities, contingent or otherwise, of
such Person (a) for borrowed money (whether or not the recourse of the lender is
to the whole of the assets of such Person or only to a portion thereof), (b)
evidenced by a note, debenture, bond or written instrument (including a purchase
money obligation), (c) in respect of leases of such Person required, in
conformity with generally accepted accounting principles, to be accounted for as
capitalized lease obligations on the balance sheet of such Person and all
obligations and other liabilities (contingent or otherwise) under any lease or
related document (including a purchase agreement) in connection with the lease
of real property which provides that such Person is contractually obligated to
purchase or cause a third party to purchase the leased property and thereby
guarantee a minimum residual value of the leased property to the lessor and the
obligations of such Person under such lease or related document to purchase or
to cause a third party to purchase such leased property or (d) in respect of
letters of credit (including reimbursement obligations and other liabilities
with respect thereto), bankers' acceptances or bank guarantees; (ii) all
obligations, indebtedness and other liabilities, contingent or otherwise, of
others of the type described in clause (i) above or in clause (iii), (iv) or (v)
below assumed by or guaranteed in any manner by such Person or in effect
guaranteed by such Person through an agreement to purchase, contingent or
otherwise (and the obligations of such Person under any such assumptions,
guarantees or other such arrangements); (iii) all obligations secured by a
mortgage, pledge, lien, encumbrance, charge or adverse claim affecting title or
resulting in an encumbrance to which the property or assets of such Person are
subject, whether or not the obligation secured thereby shall have been assumed
by or shall otherwise be such Person's legal liability; (iv) to the extent not
otherwise included, all obligations, indebtedness

<PAGE>
                                       -3-

and other liabilities, contingent or otherwise, of such Person under interest
rate and currency swap agreements, foreign exchange contracts, currency exchange
agreements, interest rate protection agreements, hedge agreements, cap, floor
and collar agreements, spot and forward contracts and similar agreements and
arrangements; and (v) all obligations, indebtedness and other liabilities,
contingent or otherwise, of such Person under or in respect of any and all
deferrals, renewals, extensions, refinancings, replacements and refundings of,
or amendments, modifications or supplements to, any liability of the kind
described in any of the preceding clauses (i), (ii), (iii) or (iv).

                  "INDENTURE" means this Indenture as amended or supplemented
from time to time.

                  "INSTITUTIONAL ACCREDITED INVESTOR" means an "accredited
investor" within the meaning of Rule 501(a)(1), (2), (3) or (7) under the
Securities Act that is an institutional investor.

                  "INTEREST" means, with respect to any Security, interest on
the Security plus liquidated damages, if any.

                  "ISSUE DATE" means (i) December 18, 2000 with respect to the
$250,000,000 aggregate principal amount of Securities issued on such date, and
(ii) with respect to any of up to $50,000,000 aggregate principal amount of
Securities that may be issued after December 18, 2000 pursuant to the option
described in Section 2.01, the respective issue date of such Securities.

                  "LIQUIDATED DAMAGES" has the meaning provided in the
Registration Rights Agreement.

                  "MATURITY DATE" means December 15, 2007.

                  "NON-U.S. PERSON" means a Person who is not a U.S. Person, as
defined in Regulation S under the Securities Act.

                  "OFFICER" means the Chairman or Co-Chairman of the Board of
Directors, any Vice Chairman of the Board of Directors, its Chief Executive
Officer, its Chief Operating Officer, the President, any Vice President, the
Chief Financial Officer, the Treasurer or the Secretary of the Company.

                  "OFFICERS' CERTIFICATE" means a certificate signed by two
Officers or by an Officer and an Assistant Treasurer or an Assistant Secretary
of the Company.

                  "OPINION OF COUNSEL" means a written opinion from legal
counsel who may be an employee of or counsel for the Company or other counsel
reasonably acceptable to the Trustee.

                  "PERSON" means any individual, corporation, partnership, joint
venture, association, joint-stock company, limited liability company, trust,
unincorporated organization or government or other agency or political
subdivision thereof.

                  "PRINCIPAL" of a debt security means the principal of the
security plus the premium, if any, on the security.

<PAGE>
                                       -4-

                  "QIB" means a "qualified institutional buyer" within the
meaning of Rule 144A under the Securities Act.

                  "REGISTRATION RIGHTS AGREEMENT" means the Registration Rights
Agreement dated as of December 18, 2000 between the Company and the Initial
Purchasers.

                  "REGULATION S" means Regulation S under the Securities Act.

                  "REGULATION S GLOBAL SECURITY" means a permanent Global
Security in registered form representing the aggregate principal amount of
Securities sold in reliance on Regulation S.

                  "RESTRICTED SECURITY" means a Security that constitutes a
"Restricted Security" within the meaning of Rule 144(a)(3) under the Securities
Act; PROVIDED, HOWEVER, that the Trustee shall be entitled to request and
conclusively rely on an Opinion of Counsel with respect to whether any Security
constitutes a Restricted Security.

                  "RULE 144A GLOBAL SECURITY" means a permanent Global Security
in registered form representing the aggregate principal amount of Securities
sold in reliance on Rule 144A.

                  "SEC" means the Securities and Exchange Commission.

                  "SECURITIES" means the 5% Convertible Subordinated Notes Due
2007 issued by the Company pursuant to this Indenture.

                  "SECURITIES ACT" means the Securities Act of 1933, as amended.

                  "SENIOR INDEBTEDNESS" means the principal of, premium, if any,
and interest on, rent payable under, and any other amounts due on or in
connection with any and all Indebtedness of the Company (including, without
limitation, fees, costs, expenses and any interest accruing after the filing of
a petition initiating any proceeding pursuant to any bankruptcy law, but only to
the extent allowed or permitted to the holder of such Indebtedness against the
bankruptcy or other insolvency estate of the Company in such proceeding),
whether outstanding on the date of this Indenture or thereafter created,
incurred, assumed, guaranteed or in effect guaranteed by the Company (including
all deferrals, renewals, extensions, refinancings, replacements or refundings
of, or amendments, modifications or supplements to the foregoing); PROVIDED,
HOWEVER, that Senior Indebtedness does not include (i) Indebtedness evidenced by
the Securities, (ii) Indebtedness of the Company to any subsidiary of the
Company except to the extent such Indebtedness is pledged by such subsidiary as
security for any Senior Indebtedness, (iii) accounts payable of the Company to
trade creditors arising in the ordinary course of business, and (iv) any
particular Indebtedness in which the instrument creating or evidencing the same
or the assumption or guarantee thereof expressly provides that such Indebtedness
shall not be senior in right of payment to, or is PARI PASSU with, or is
subordinated or junior to, the Securities.

                  "SUBSIDIARY" means (i) a corporation a majority of whose
capital stock with voting power, under ordinary circumstances, to elect
directors is at the time, directly or indirectly, owned by the Company, by one
or more subsidiaries of the Company or by the Company and one or more sub-

<PAGE>
                                       -5-

sidiaries thereof or (ii) any other Person (other than a corporation) in
which the Company, one or more subsidiaries thereof or the Company and one or
more subsidiaries thereof, directly or indirectly, at the date of
determination thereof, have at least majority ownership interest.

                  "TIA" means the Trust Indenture Act of 1939 (15 U.S. Code
Sections 77aaa-77bbbb) as in effect on tHe date of this Indenture, except as
provided in Section 9.03.

                  "TRUST OFFICER" means any officer of the Trustee assigned by
the Trustee to administer this Indenture.

                  "TRUSTEE" means the party named as such in this Indenture
until a successor replaces it in accordance with the provisions hereof and
thereafter means the successor.

SECTION 1.02.         OTHER DEFINITIONS.

<TABLE>
<CAPTION>
                   Term                                                           Defined in Section
                   ----                                                           ------------------
<S>                                                                               <C>
          "Bankruptcy Law"..............................................                 6.01
          "Business Day"................................................                13.07
          "Change in Control"...........................................                 3.07(l)
          "Closing Price"...............................................                10.06(h)
          "Common Dividend Amount"......................................                10.06(e)
          "Company Notice"..............................................                 3.07(b)
          "Continuing Director".........................................                 3.07(l)
          "Conversion Agent"............................................                 2.03
          "Current Market Price"........................................                10.06(h)
          "Custodian"...................................................                 6.01
          "Event of Default"............................................                 6.01
          "fair market value"...........................................                10.06(h)
          "Global Security".............................................                 2.01
          "Initial Purchasers"..........................................                 2.02
          "Legal Holiday"...............................................                13.07
          "Market Capitalization".......................................                10.06(e)
          "Participants"................................................                 2.15
          "Paying Agent"................................................                 2.03
          "Payment Blockage Notice".....................................                12.01(b)
          "Payment Blockage Period".....................................                12.01(b)
          "Payment Default".............................................                12.01(b)
          "Physical Securities".........................................                 2.15(b)
          "Private Placement Legend"....................................                 2.17
          "Record Date".................................................                10.06(h)
          "Registrar"...................................................                 2.03
          "Repurchase Date".............................................                 3.07(a)
          "Repurchase Event"............................................                 3.07(l)
          "Repurchase Price"............................................                 3.07(a)
</TABLE>

<PAGE>
                                       -6-
<TABLE>
<S>                                                                               <C>
          "Subject Securities"..........................................                10.06(d)
          "Termination of Trading"......................................                 3.07(l)
          "Trading Day".................................................                10.06(h)
          "Trigger Event"...............................................                10.06(d)
          "U.S. Government Obligations".................................                 8.01
</TABLE>

SECTION 1.03.         INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT.

                  Whenever this Indenture refers to a provision of the TIA, the
provision is incorporated by reference in and made a part of this Indenture.

                  The following TIA terms used in this Indenture have the
following meanings:

                  "Commission" means the SEC;

                  "indenture securities" means the Securities;

                  "indenture security holder" means a Holder;

                  "indenture to be qualified" means this Indenture;

                  "indenture trustee" or "institutional trustee" means the
Trustee; and

                  "obligor" on the indenture securities means the Company.

                  All other terms used in this Indenture that are defined by the
TIA, defined by TIA reference to another statute or defined by SEC rule under
the TIA and not otherwise defined herein have the meanings so assigned to them.

SECTION 1.04.         RULES OF CONSTRUCTION.

                  Unless the context otherwise requires:

                  (1)      a term has the meaning assigned to it;

                  (2)      an accounting term not otherwise defined has the
           meaning assigned to it in accordance with generally accepted
           accounting principles in effect on the date hereof;

                  (3)      "or" is not exclusive;

                  (4)      words in the singular include the plural and in
           the plural include the singular;

                  (5)      provisions apply to successive events and
           transactions; and

                  (6)      "herein", "hereof" and other words of similar
           import refer to this Indenture as a whole and not to any
           particular Article, Section or other subdivision.

<PAGE>
                                       -7-

                                   ARTICLE TWO

                                  THE SECURITIES

SECTION 2.01.         FORM AND DATING.

                  The Securities and the Trustee's certificate of authentication
shall be substantially in the form set forth in EXHIBIT A, which is incorporated
in and forms a part of this Indenture. The Securities may have notations,
legends or endorsements required by law, stock exchange rule or usage. Each
Security shall be dated the date of its authentication.

                  Securities offered and sold in reliance on Rule 144A,
Securities offered and sold in reliance on Regulation S and Securities
subsequently transferred to Institutional Accredited Investors shall be issued
initially in the form of one or more Global Securities, substantially in the
form set forth in EXHIBIT A (the "GLOBAL SECURITY"). The aggregate principal
amount of the Global Security may from time to time be increased or decreased by
adjustments made on the records of the Trustee, as custodian for the Depository,
as hereinafter provided.

SECTION 2.02.         EXECUTION AND AUTHENTICATION.

                  One Officer shall sign the Securities for the Company by
manual or facsimile signature.

                  If an Officer whose signature is on a Security no longer holds
that office at the time the Security is authenticated, the Security shall
nevertheless be valid.

                  A Security shall not be valid until authenticated by the
manual signature of the Trustee. The signature shall be conclusive evidence that
the Security has been authenticated under this Indenture.

                  Upon a written order of the Company signed by an Officer of
the Company, the Trustee shall authenticate Securities for original issue in the
principal amount of $250,000,000 and such additional principal amounts, if any,
as shall be determined pursuant to the next sentence of this Section 2.02. Upon
receipt by the Trustee of an Officers' Certificate stating that the Initial
Purchasers have elected to purchase from the Company a specified principal
amount of additional Securities, not to exceed $50,000,000, pursuant to Section
l of the Purchase Agreement dated as of December 13, 2000 between the Company,
as issuer, and J.P. Morgan Securities Inc., Lehman Brothers Inc. and Morgan
Stanley & Co. Incorporated, as initial purchasers (the "INITIAL PURCHASERS"),
the Trustee shall authenticate and deliver such specified principal amount of
additional Securities to or upon the written order of the Company signed as
provided in the immediately preceding sentence. Such Officers' Certificate must
be received by the Trustee at least two full Business Days prior to the proposed
date for delivery of such additional Securities, but, in any case, not later
than January 15, 2001. The aggregate principal amount of Securities outstanding
at any time may not exceed $300,000,000 except as provided in Section 2.07.

<PAGE>
                                       -8-

                  Upon a written order of the Company signed by two Officers or
by an Officer and an Assistant Treasurer of the Company, the Trustee shall
authenticate Securities not bearing the Private Placement Legend to be issued to
the transferee when sold pursuant to an effective registration statement under
the Securities Act.

                  The Trustee may appoint an authenticating agent acceptable to
the Company to authenticate Securities. An authenticating agent may authenticate
Securities whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such Agent. An
authenticating agent has the same rights as an Agent to deal with the Company or
an Affiliate.

                  The Securities shall be issuable only in registered form
without coupons and only in denominations of $1,000 principal amount and any
integral multiple thereof. The Securities shall bear interest at the rate,
calculated and paid, as provided in the form set forth in EXHIBIT A.

SECTION 2.03.         REGISTRAR, PAYING AGENT AND CONVERSION AGENT.

                  The Company shall maintain an office or agency where
Securities may be presented for registration of transfer or for exchange
("REGISTRAR"), an office or agency where Securities may be presented for payment
("PAYING AGENT") and an office or agency where Securities may be presented for
conversion ("CONVERSION AGENT"). The Registrar shall keep a register of the
Securities and of their transfer and exchange. The Company may appoint or change
one or more co-registrars, one or more additional paying agents and one or more
additional conversion agents without notice and may act in any such capacity on
its own behalf. The term "Registrar" includes any co-registrar; the term "Paying
Agent" includes any additional paying agent; the term "Conversion Agent"
includes any additional conversion agent.

                  The Company shall enter into an appropriate agency agreement
with any Agent not a party to this Indenture. The agreement shall implement the
provisions of this Indenture that relate to such Agent. The Company shall notify
the Trustee of the name and address of any Agent not a party to this Indenture.
If the Company fails to maintain a Registrar, Paying Agent or Conversion Agent,
the Trustee shall act as such.

                  The Company initially appoints the Trustee as Paying Agent,
Registrar and Conversion Agent.

SECTION 2.04.         PAYING AGENT TO HOLD MONEY IN TRUST.

                  Each Paying Agent shall hold in trust for the benefit of the
Holders or the Trustee all moneys held by the Paying Agent for the payment of
principal of or interest on the Securities, and shall notify the Trustee of any
default by the Company in making any such payment. While any such default
continues, the Trustee may require a Paying Agent to pay all money held by it to
the Trustee. The Company at any time may require a Paying Agent to pay all money
held by it to the Trustee. Upon payment over to the Trustee, the Paying Agent
shall have no further liability for the money. If

<PAGE>
                                       -9-

the Company acts as Paying Agent, it shall segregate and hold as a separate
trust fund all money held by it as Paying Agent.

SECTION 2.05.         SECURITYHOLDER LISTS.

                  The Trustee shall preserve in as current a form as is
reasonably practicable the most recent list available to it of the names and
addresses of Holders. If the Trustee is not the Registrar, the Company shall
furnish to the Trustee on or before each interest payment date and at such other
times as the Trustee may request in writing a list, in such form and as of such
date as the Trustee may reasonably require, of the names and addresses of
Holders.

SECTION 2.06.         TRANSFER AND EXCHANGE.

                  Where Securities are presented to the Registrar with a request
to register their transfer or to exchange them for an equal principal amount of
Securities of other authorized denominations, the Registrar shall register the
transfer or make the exchange if its requirements for such transaction are met.
To permit registrations of transfer and exchanges, the Company shall execute and
the Trustee shall authenticate Securities at the Registrar's request. The
Company or the Trustee, as the case may be, shall not be required (a) to issue
or authenticate, register the transfer of or exchange any Security during a
period beginning at the opening of business 15 days before the mailing of a
notice of redemption of the Securities selected for redemption under Section
3.03 and ending at the close of business on the day of such mailing, or (b) to
register the transfer of or exchange any Security so selected for redemption in
whole or in part, except the unredeemed portion of Securities being redeemed in
part.

                  No service charge shall be made for any registration of
transfer, exchange or conversion of Securities, but the Company may require
payment of a sum sufficient to cover any tax or other governmental charge that
may be imposed in connection with any transfer, registration of transfer or
exchange of Securities, other than exchanges pursuant to Sections 2.10, 3.06,
9.05 or 10.02 not involving any transfer.

SECTION 2.07.         REPLACEMENT SECURITIES.

                  If the Holder of a Security claims that the Security has been
mutilated, lost, destroyed or wrongfully taken, the Company shall issue and the
Trustee shall authenticate a replacement Security if the Trustee's requirements
are met and, in the case of a mutilated Security, such mutilated Security is
surrendered to the Trustee. In the case of lost, destroyed or wrongfully taken
Securities, if required by the Trustee or the Company, an indemnity bond must be
provided by the Holder that is sufficient in the judgment of both to protect the
Company, the Trustee or any Agent from any loss which any of them may suffer if
a Security is replaced. The Company or the Trustee may charge for its expenses
in replacing a Security.

                  In case any such mutilated, lost, destroyed or wrongfully
taken Security has become or is about to become due and payable, the Company in
its discretion may, instead of issuing a new Security, pay such Security when
due.

<PAGE>
                                       -10-

                  Every replacement Security is an additional obligation of the
Company.

SECTION 2.08.         OUTSTANDING SECURITIES.

                  Securities outstanding at any time are all the Securities
authenticated by the Trustee except for those converted, those cancelled by it,
those delivered to it for cancellation and those described in this Section as
not outstanding. A Security does not cease to be outstanding because the Company
or one of its subsidiaries or Affiliates holds the Security.

                  If a Security is replaced pursuant to Section 2.07, it ceases
to be outstanding unless the Trustee receives proof satisfactory to it, or a
court holds, that the replaced Security is held by a protected purchaser.

                  If the Paying Agent (other than the Company) holds on a
redemption date or maturity date money sufficient to pay Securities payable on
that date, then on and after that date, such Securities shall be deemed to be no
longer outstanding and interest on them shall cease to accrue.

SECTION 2.09.         SECURITIES HELD BY THE COMPANY OR AN AFFILIATE.

                  In determining whether the Holders of the required aggregate
principal amount of Securities have concurred in any direction, waiver or
consent, Securities owned by the Company or a subsidiary or an Affiliate shall
be disregarded, except that for the purposes of determining whether the Trustee
shall be protected in relying on any such direction, waiver or consent, only
Securities which a Trust Officer knows are so owned shall be so disregarded.

SECTION 2.10.         TEMPORARY SECURITIES.

                  Until definitive Securities are ready for delivery, the
Company may prepare and the Trustee shall authenticate temporary Securities.
Temporary Securities shall be substantially in the form of definitive Securities
but may have variations that the Company considers appropriate for temporary
Securities. Without unreasonable delay, the Company shall prepare and the
Trustee shall authenticate definitive Securities in exchange for temporary
Securities.

SECTION 2.11.         CANCELLATION.

                  The Company at any time may deliver Securities to the Trustee
for cancellation. The Registrar, Paying Agent and Conversion Agent shall forward
to the Trustee any Securities surrendered to them for registration of transfer,
exchange, payment or conversion. The Trustee shall cancel all Securities
surrendered for registration of transfer, exchange, payment, conversion or
cancellation and the Trustee may, but shall not be required to, destroy
cancelled Securities and deliver a certificate of any such destruction to the
Company or return such cancelled Securities to the Company. The Company may not
issue new Securities to replace Securities that it has paid or delivered to the
Trustee for cancellation or that any Holder has converted pursuant to Article
Ten.

<PAGE>
                                       -11-

SECTION 2.12.         DEFAULTED INTEREST.

                  If and to the extent the Company defaults in a payment of
interest on the Securities, it shall pay the defaulted interest in any lawful
manner plus, to the extent not prohibited by applicable statute or case law,
interest payable on the defaulted interest. It may pay the defaulted interest to
the Persons who are Holders on a subsequent special record date. The Company
shall fix such record date and payment date. At least 15 days before the record
date, the Company shall mail to Holders a notice that states the record date,
payment date and amount of interest to be paid.

SECTION 2.13.         CUSIP NUMBERS.

                  The Company in issuing the Securities may use one or more
"CUSIP" numbers, and if so, the Trustee shall use the CUSIP numbers in notices
of redemption or exchange as a convenience to Holders; PROVIDED, HOWEVER, that
no representation is hereby deemed to be made by the Trustee as to the
correctness or accuracy of the CUSIP numbers printed in the notice or on the
Securities, and that reliance may be placed only on the other identification
numbers printed on the Securities. The Company shall promptly notify the Trustee
of any change in the CUSIP number.

SECTION 2.14.         DEPOSIT OF MONEYS.

                  Prior to the close of business on the day prior to each
interest payment date, maturity date, redemption date and Repurchase Date, the
Company shall have deposited with the Paying Agent in immediately available
funds money sufficient to make cash payments, if any, due on such interest
payment date, maturity date, redemption date and Repurchase Date, as the case
may be, in a timely manner which permits the Paying Agent to remit payment to
the Holders on such interest payment date, maturity date, redemption date and
Repurchase Date, as the case may be.

SECTION 2.15.         BOOK-ENTRY PROVISIONS FOR GLOBAL SECURITIES.

                  (a) The Global Securities initially shall (i) be registered in
the name of the Depository or the nominee of such Depository, (ii) be delivered
to the Trustee as custodian for such Depository and (iii) bear the legend for
Global Securities as set forth in EXHIBIT B(II).

                  Members of, or participants in, the Depository
("PARTICIPANTS") shall have no rights under this Indenture with respect to any
Global Security held on their behalf by the Depository, or the Trustee as its
custodian, or under the Global Security, and the Depository may be treated by
the Company, the Trustee and any agent of the Company or the Trustee as the
absolute owner of the Global Security for all purposes whatsoever.
Notwithstanding the foregoing, nothing herein shall prevent the Company, the
Trustee or any agent of the Company or the Trustee from giving effect to any
written certification, proxy or other authorization furnished by the Depository
or impair, as between the Depository and Participants, the operation of
customary practices governing the exercise of the rights of a Holder of any
Security.

                  (b) Transfers of Global Securities shall be limited to
transfers in whole, but not in part, to the Depository, its successors or their
respective nominees. In addition, permanent certifi-

<PAGE>
                                       -12-

cated Securities in registered form, in the form set forth in EXHIBIT A (the
"PHYSICAL SECURITIES"), shall be transferred to all beneficial owners in
exchange for their beneficial interests in Global Securities if (i) the
Depository notifies the Company that it is unwilling or unable to continue as
Depository for any Global Security and a successor Depository is not appointed
by the Company within 90 days of such notice or (ii) an Event of Default has
occurred and is continuing and the Registrar has received a written request from
the Depository to issue Physical Securities.

                  (c) In connection with any transfer or exchange of a portion
of the beneficial interest in a Global Security to beneficial owners pursuant to
paragraph (b), the Registrar shall (if one or more Physical Securities are to be
issued) reflect on its books and records the date and a decrease in the
aggregate principal amount of such Global Security in an amount equal to the
aggregate initial aggregate principal amount of the beneficial interest in the
Global Security to be transferred, and the Company shall execute and the Trustee
shall authenticate and deliver one or more Physical Securities of authorized
denominations in an aggregate principal amount equal to the aggregate principal
amount of the beneficial interest in the Global Security so transferred.

                  (d) In connection with the transfer of a Global Security in
its entirety to beneficial owners pursuant to paragraph (b) of this Section
2.15, such Global Security shall be deemed to be surrendered to the Trustee for
cancellation, and the Company shall execute, and the Trustee shall upon written
instructions from the Company authenticate and deliver, to each beneficial owner
identified by the Depository in exchange for its beneficial interest in such
Global Security, an equal aggregate principal amount of Physical Securities of
authorized denominations.

                  (e) Any Physical Security constituting a Restricted Security
delivered in exchange for an interest in a Global Security pursuant to paragraph
(b) or (c) of this Section 2.15 shall, except as otherwise provided by Section
2.16, bear the Private Placement Legend.

                  (f) The Holder of any Global Security may grant proxies and
otherwise authorize any Person, including Participants and Persons that may hold
interests through Participants, to take any action which a Holder is entitled to
take under this Indenture or the Securities.

SECTION 2.16.         SPECIAL TRANSFER PROVISIONS.

                  (a)  TRANSFERS TO NON-QIB INSTITUTIONAL ACCREDITED INVESTORS
AND NON-U.S. PERSONS. The following provisions shall apply with respect to the
registration of any proposed transfer of a Restricted Security to any
Institutional Accredited Investor which is not a QIB or to any Non-U.S. Person:

                  (i) the Registrar shall register the transfer of any
         Restricted Security, whether or not such Security bears the Private
         Placement Legend, if (x) the requested transfer is after the second
         anniversary of the Issue Date for such Security; PROVIDED, HOWEVER,
         that the transferor shall represent to the Registrar that, to the
         transferor's knowledge, neither the Company nor any Affiliate of the
         Company has held any beneficial interest in such Security, or portion
         thereof, at any time on or prior to the second anniversary of the Issue
         Date for such Security or (y)(1) in the case of a transfer to an
         Institutional Accredited Investor which is not a QIB

<PAGE>
                                       -13-

         (excluding Non-U.S. Persons), the proposed transferee has delivered to
         the Registrar a certificate substantially in the form of EXHIBIT C
         hereto and any legal opinions and certifications required thereby and
         (2) in the case of a transfer to a Non-U.S. Person, the proposed
         transferee has delivered to the Registrar a certificate substantially
         in the form of EXHIBIT D hereto;

                 (ii) if the proposed transferee is a Participant and the
         Securities to be transferred consist of Physical Securities which after
         transfer are to be evidenced by an interest in the Global Security,
         upon receipt by the Registrar of (x) written instructions given in
         accordance with the Depository's and the Registrar's procedures and (y)
         the appropriate certificate, if any, required by clause (y) of
         paragraph (i) above, the Registrar shall register the transfer and
         reflect on its books and records the date and an increase in the
         aggregate principal amount of the Global Security in an amount equal to
         the aggregate principal amount of Physical Securities to be
         transferred, and the Trustee shall cancel the Physical Securities so
         transferred; and

                (iii) if the proposed transferor is a Participant seeking to
         transfer an interest in the Rule 144A Global Security, upon receipt by
         the Registrar of (x) written instructions given in accordance with the
         Depository's and the Registrar's procedures and (y) the appropriate
         certificate, if any, required by clause (y) of paragraph (i) above, the
         Registrar shall register the transfer and reflect on its books and
         records the date and (A) a decrease in the aggregate principal amount
         of the Rule 144A Global Security in an amount equal to the aggregate
         principal amount of the Securities to be transferred and (B) an
         increase in the aggregate principal amount of the Regulation S Global
         Security or the IAI Global Security, as the case may be, in an amount
         equal to the aggregate principal amount of the Securities to be
         transferred.

                  (b) TRANSFERS TO QIBS. The following provisions shall apply
with respect to the registration of any proposed transfer of a Restricted
Security to a QIB:

                  (i) the Registrar shall register the transfer of any
         Restricted Security, whether or not such Security bears the Private
         Placement Legend, if (x) the requested transfer is after the second
         anniversary of the Issue Date for such Security; PROVIDED, HOWEVER,
         that the transferor shall represent to the Registrar that, to the
         transferor's knowledge, neither the Company nor any Affiliate of the
         Company has held any beneficial interest in such Security, or portion
         thereof, at any time on or prior to the second anniversary of the Issue
         Date for such Security or (y) such transfer is being made by a proposed
         transferor who has checked the box provided for on the form of Security
         stating, or has otherwise advised the Company and the Registrar in
         writing, that the sale has been made in compliance with the provisions
         of Rule 144A to a transferee who has signed the certification provided
         for on the form of Security stating, or has otherwise advised the
         Company and the Registrar in writing, that it is purchasing the
         Security for its own account or an account with respect to which it
         exercises sole investment discretion and that it and any such account
         is a QIB within the meaning of Rule 144A, and is aware that the sale to
         it is being made in reliance on Rule 144A and acknowledges that it has
         received such information regarding the Company as it has requested
         pursuant to Rule 144A or has determined not to request such information
         and that it is aware that the transferor is relying upon its foregoing
         representations in order to claim the exemption from registration
         provided by Rule 144A;

<PAGE>
                                       -14-

                 (ii) if the proposed transferee is a Participant and the
         Securities to be transferred consist of Physical Securities which after
         transfer are to be evidenced by an interest in the Global Security,
         upon receipt by the Registrar of written instructions given in
         accordance with the Depository's and Registrar's procedures, the
         Registrar shall register the transfer and reflect on its books and
         records the date and an increase in the principal amount of the Global
         Security in an amount equal to the principal amount of Physical
         Securities to be transferred, and the Trustee shall cancel the Physical
         Security so transferred; and

                (iii) if the proposed transferor is a Participant seeking to
         transfer an interest in the Regulation S Global Security or the IAI
         Global Security, upon receipt by the Registrar of written instructions
         given in accordance with the Depository's and the Registrar's
         procedures, the Registrar shall register the transfer and reflect on
         its books and records the date and (A) a decrease in the aggregate
         principal amount of the Regulation S Global Security or the IAI Global
         Security, as the case may be, in an amount equal to the aggregate
         principal amount of the Securities to be transferred and (B) an
         increase in the aggregate principal amount of the Rule 144A Global
         Security in an amount equal to the aggregate principal amount of the
         Securities to be transferred.

                  (c) RESTRICTIONS ON TRANSFER AND EXCHANGE OF GLOBAL
SECURITIES. Notwithstanding any other provisions of this Indenture, a Global
Security may not be transferred as a whole except by the Depository to a nominee
of the Depository or by a nominee of the Depository to the Depository or another
nominee of the Depository or by the Depository or any such nominee to a
successor Depository or a nominee of such successor Depository.

                  (d) PRIVATE PLACEMENT LEGEND. Upon the registration of
transfer, exchange or replacement of Securities not bearing the Private
Placement Legend, the Registrar or co-Registrar shall deliver Securities that do
not bear the Private Placement Legend. Upon the registration of transfer,
exchange or replacement of Securities bearing the Private Placement Legend, the
Registrar or co-Registrar shall deliver only Securities that bear the Private
Placement Legend unless (i) the requested transfer is after the second
anniversary of the Issue Date for such Security (PROVIDED, HOWEVER, that neither
the Company nor any Affiliate of the Company has held any beneficial interest in
such Security, or portion thereof, at any time prior to or on the second
anniversary of the Issue Date for such Security), (ii) there is delivered to the
Trustee an Opinion of Counsel reasonably satisfactory to the Company to the
effect that neither such legend nor the related restrictions on transfer are
required in order to maintain compliance with the provisions of the Securities
Act or (iii) such Security has been sold pursuant to an effective registration
statement under the Securities Act and the Holder selling such Securities has
delivered to the Registrar or co-Registrar a notice in the form of EXHIBIT E
hereto. Upon the effectiveness of the Shelf Registration Statement (as defined
in the Registration Rights Agreement) the Company shall deliver to the Trustee a
notice of effectiveness, a Security or Securities and an authentication order in
accordance with Section 2.02 and, if required by the Depository, the Company
shall deliver to the Depository a letter of representations in a form reasonably
acceptable to the Depository.

                  (e) GENERAL. By its acceptance of any Security bearing the
Private Placement Legend, each Holder of such a Security acknowledges the
restrictions on transfer of such Security set

<PAGE>
                                       -15-

forth in this Indenture and in the Private Placement Legend and agrees that it
will transfer such Security only as provided in this Indenture.

                  The Registrar shall retain, in accordance with its customary
procedures, copies of all letters, notices and other written communications
received pursuant to Section 2.15 or this Section 2.16. The Company shall have
the right to inspect and make copies of all such letters, notices or other
written communications at any reasonable time upon the giving of reasonable
notice to the Registrar.

                  (f) TRANSFERS OF SECURITIES HELD BY AFFILIATES. Any
certificate (i) evidencing a Security that has been transferred to an Affiliate
of the Company within two years after the Issue Date for such Security, as
evidenced by a notation on the Assignment Form for such transfer or in the
representation letter delivered in respect thereof or (ii) evidencing a Security
that has been acquired from an Affiliate (other than by an Affiliate) in a
transaction or a chain of transactions not involving any public offering, shall,
until two years after the last date on which either the Company or any Affiliate
of the Company was an owner of such Security, in each case, bear the Private
Placement Legend, unless otherwise agreed by the Company (with written notice
thereof to the Trustee).

SECTION 2.17.         RESTRICTIVE LEGENDS.

                  Each Global Security and Physical Security that constitutes a
Restricted Security shall bear the private placement legend (the "PRIVATE
PLACEMENT LEGEND") as set forth in EXHIBIT B(I) on the face thereof until after
the second anniversary of the later of the Issue Date for such Securities and
the last date on which the Company or any Affiliate of the Company was the owner
of such Security (or any predecessor security) (or such shorter period of time
as permitted by Rule 144(k) under the Securities Act or any successor provision
thereunder) (or such longer period of time as may be required under the
Securities Act or applicable state securities laws in the opinion of counsel for
the Company, unless otherwise agreed by the Company and the Holder thereof).

                                  ARTICLE THREE

                             REDEMPTION; REPURCHASE

SECTION 3.01.         NOTICES TO TRUSTEE.

                  If the Company wants to redeem Securities pursuant to
paragraph 6 of the Securities, it shall notify the Trustee at least 45 days
prior to the redemption date (unless a shorter notice period shall be
satisfactory to the Trustee) of the redemption date and the aggregate principal
amount of Securities to be redeemed. If the Company wants to credit against any
such redemption Securities it has not previously delivered to the Trustee for
cancellation (other than Securities repurchased pursuant to Section 3.07), it
shall deliver the Securities with the notice.

<PAGE>
                                       -16-

SECTION 3.02.         SELECTION OF SECURITIES TO BE REDEEMED.

                  If less than all the Securities are to be redeemed, the
Trustee shall select the Securities to be redeemed on either a pro rata basis or
by lot or such other method as the Trustee shall deem fair and equitable. The
Trustee shall make the selection from Securities outstanding not previously
called for redemption. The Trustee may select for redemption portions of the
principal of Securities that have denominations larger than $1,000 principal
amount. Securities and portions of them it selects shall be in amounts of $1,000
principal amount or whole multiples of $1,000 principal amount. Provisions of
this Indenture that apply to Securities called for redemption also apply to
portions of Securities called for redemption.

                  The Registrar need not register the transfer of or exchange
any Securities selected for redemption. Also, the Registrar need not transfer or
exchange any Securities for a period of 15 days before selecting Securities to
be redeemed.

SECTION 3.03.         NOTICE OF REDEMPTION.

                  At least 30 days but not more than 60 days before a redemption
date, the Company shall mail by first-class mail or cause to be mailed a notice
of redemption to each Holder whose Securities are to be redeemed.

                  The notice shall identify the Securities and the aggregate
principal amount thereof to be redeemed and shall state:

                  (1)      the redemption date;

                  (2)      the redemption price, plus the amount of accrued
           and unpaid interest to be paid on the Securities called for
           redemption;

                  (3)      the then current conversion rate;

                  (4)      the name and address of the Paying Agent and
           Conversion Agent;

                  (5)      the date on which the right to convert the
           principal of the Securities called for redemption will terminate
           and the place or places where such Securities may be surrendered
           for conversion;

                  (6)      that Holders who want to convert Securities must
           satisfy the requirements in Article Ten;

                  (7)      that Securities called for redemption must be
           surrendered to the Paying Agent to collect the redemption price;

                  (8)      that interest on Securities called for redemption
           ceases to accrue on and after the redemption date; and

<PAGE>
                                       -17-

                  (9)      the CUSIP number of the Securities.

                  The date on which the right to convert the principal of the
Securities called for redemption will terminate shall be at the close of
business on the date prior to the redemption date, or, if the day before the
redemption date is a Legal Holiday, the close of business on the next preceding
day which is not a Legal Holiday.

                  At the Company's request (which request shall be furnished to
the Trustee at least 45 days prior to the redemption date (unless a shorter
period shall be acceptable to the Trustee)), the Trustee shall give the notice
of redemption in the Company's name and at the Company's expense; provided that
the form and content of such notice shall be prepared by the Company.

SECTION 3.04.         EFFECT OF NOTICE OF REDEMPTION.

                  Once notice of redemption is mailed, Securities called for
redemption become due and payable on the redemption date at the redemption price
plus accrued and unpaid interest to the date of redemption, and, on and after
such date (unless the Company shall default in the payment of the redemption
price), such Securities shall cease to bear interest. Upon surrender to the
Paying Agent, such Securities shall be paid at the redemption price plus accrued
interest to the redemption date, unless the redemption date is an interest
payment date, in which case the accrued interest will be paid in the ordinary
course.

SECTION 3.05.         DEPOSIT OF REDEMPTION PRICE.

                  By the close of business on the day prior to the redemption
date, the Company shall deposit with the Paying Agent pursuant to Section 2.14
money in funds immediately available on the redemption date sufficient to pay
the redemption price of and accrued interest on all Securities to be redeemed on
that date. The Paying Agent shall return to the Company, as soon as practicable,
any money not required for that purpose because of conversion of Securities.

SECTION 3.06.         SECURITIES REDEEMED IN PART.

                  Upon surrender of a Security that is redeemed in part, the
Company shall execute and the Trustee shall authenticate for the Holder a new
Security equal in principal amount to the unredeemed portion of the Security
surrendered.

                  If a portion of a Holder's Securities is selected for partial
redemption and that Holder converts a portion of that Holder's Securities, the
converted portion shall be deemed (as far as may be) to be the portion selected
for redemption.

SECTION 3.07.         REPURCHASE AT OPTION OF HOLDER UPON A REPURCHASE EVENT.

                  (a) If there shall occur a Repurchase Event (as defined in (l)
below), then each Holder shall have the right, at such Holder's option, to
require the Company to repurchase all of such Holder's Securities, or any
portion thereof (in principal amounts of $1,000 or integral multiples

<PAGE>
                                       -18-

thereof), on the date (the "REPURCHASE DATE") that is forty (40) calendar days
after the date of the Company Notice (as defined below) of such Repurchase Event
(or, if such 40th day is not a Business Day, the next succeeding Business Day).
Such repurchase shall be made in cash at a price equal to 100% of the principal
amount of Securities such Holder elects to require the Company to repurchase,
together with accrued interest, if any, to but excluding the Repurchase Date
(the "REPURCHASE PRICE") (or, at the option of the Company, by delivery of
Common Stock in accordance with the provisions of Section 3.07(k)); PROVIDED,
HOWEVER, that if such Repurchase Date is June 15 or December 15, then the
interest payable on such date shall be paid to the holder of record of the
Security on the next preceding June 1 or December 1, respectively. No Securities
may be repurchased at the option of Holders upon a Repurchase Event if there has
occurred and is continuing an Event of Default, other than a default in the
payment of the Repurchase Price with respect to such Securities on the
Repurchase Date.

                  (b) Unless the Company shall have theretofore called for
redemption all of the outstanding Securities, on or before the fifteenth (15th)
calendar day after the occurrence of a Repurchase Event, the Company or, at the
written request of the Company, the Trustee shall mail to all holders of record
of the Securities a notice (the "COMPANY NOTICE") in the form prepared by the
Company of the occurrence of the Repurchase Event and of the repurchase right
set forth herein arising as a result thereof. The Company shall also deliver a
copy of such Company Notice to the Trustee and cause a copy of such Company
Notice, or a summary of the information contained therein, to be published once
in a newspaper of general circulation in The City of New York. The Company
Notice shall contain the following information:

                  (1)      the Repurchase Date;

                  (2)      the date by which the repurchase right must be
         exercised;

                  (3)      the last date by which the election to require
         repurchase, if submitted, must be revoked;

                  (4)      the Repurchase Price and whether the Repurchase
         Price shall be payable in cash or Common Stock and, if payable in
         Common Stock, the method of calculating the amount of the Common
         Stock to be delivered upon the repurchase as provided in Section
         3.07(k);

                  (5)      a description of the procedure which a Holder must
         follow to exercise a repurchase right;

                  (6)      the Conversion Price then in effect, the date on
         which the right to convert the principal amount of the Securities to be
         repurchased will terminate and the place or places where Securities may
         be surrendered for conversion; and

                  (7)      the CUSIP numbers of the Securities.

<PAGE>
                                       -19-

                  No failure of the Company to give the foregoing notices or
defect therein shall limit any Holder's right to exercise a repurchase right or
affect the validity of the proceedings for the repurchase of Securities.

                  If any of the foregoing provisions are inconsistent with
applicable law, such law shall govern.

                  (c) To exercise a repurchase right, a Holder shall deliver to
the Trustee on or before the twenty-fifth (25th) day after the Company Notice
was delivered (i) written notice to the Company (or agent designated by the
Company for such purpose) of the Holder's exercise of such right, which notice
shall set forth the name of the Holder, the principal amount of the Securities
to be repurchased, a statement that an election to exercise the repurchase right
is being made thereby, and, in the event that the Repurchase Price shall be paid
in shares of Common Stock, the name or names (with addresses) in which the
certificate or certificates for shares of Common Stock shall be issued, and (ii)
the Securities with respect to which the repurchase right is being exercised,
duly endorsed for transfer to the Company. Election of repurchase by a Holder
shall be revocable at any time prior to, but excluding, the Repurchase Date, by
delivering written notice to that effect to the Trustee prior to the close of
business on the Business Day prior to the Repurchase Date.

                  (d) If the Company fails to repurchase on the Repurchase Date
any Securities (or portions thereof) as to which the repurchase right has been
properly exercised, then the principal of such Securities shall, until paid,
bear interest to the extent permitted by applicable law from the Repurchase Date
at the rate borne by the Securities and each such Security shall be convertible
into Common Stock in accordance with this Indenture until the principal of such
Security shall have been paid or duly provided for.

                  (e) Any Security which is to be repurchased only in part shall
be surrendered to the Trustee duly endorsed for transfer to the Company and
accompanied by appropriate evidence of genuineness and authority satisfactory to
the Company and the Trustee duly executed by the Holder thereof (or his attorney
duly authorized in writing), and the Company shall execute, and the Trustee
shall authenticate and deliver to the Holder of such Security without service
charge, a new Security or Securities, containing identical terms and conditions,
of any authorized denomination as requested by such Holder in aggregate
principal amount equal to and in exchange for the unrepurchased portion of the
principal of the Security so surrendered.

                  (f) By the close of business on the day prior to the
Repurchase Date, the Company shall deposit with the Trustee or with a Paying
Agent, pursuant to Section 2.14, the Repurchase Price in cash for payment to the
Holder on the Repurchase Date; PROVIDED that if the Repurchase Price is to be
paid in shares of Common Stock, such shares of Common Stock are to be paid as
promptly after the Repurchase Date as practicable.

                  (g) Any issuance of shares of Common Stock in respect of the
Repurchase Price shall be deemed to have been effected immediately prior to the
close of business on the Repurchase Date and the Person or Persons in whose name
or names any certificate or certificates for shares of Common Stock shall be
issuable upon such repurchase shall be deemed to have become on the Repurchase

<PAGE>
                                       -20-

Date the holder or holders of record of the shares represented thereby;
PROVIDED, HOWEVER, that any surrender for repurchase on a date when the stock
transfer books of the Company shall be closed shall constitute the Person or
Persons in whose name or names the certificate or certificates for such shares
are to be issued as the record holder or holders thereof for all purposes at the
opening of business on the next succeeding day on which such stock transfer
books are open. No payment or adjustment shall be made for dividends or
distributions on any Common Stock issued upon repurchase of any Security
declared prior to the Repurchase Date.

                  (h) No fractions of shares shall be issued upon repurchase of
Securities. If more than one Security shall be repurchased from the same Holder
and the Repurchase Price shall be payable in shares of Common Stock, the number
of full shares which shall be issuable upon such repurchase shall be computed on
the basis of the aggregate principal amount of the Securities so repurchased.
Instead of any fractional share of Common Stock otherwise issuable on the
repurchase of any Security or Securities, the Company will deliver to the
applicable Holder its check for the current market value of such fractional
share. The current market value of a fraction of a share is determined by
multiplying the current market price of a full share by the fraction, and
rounding the result to the nearest cent. For purposes of this Section, the
current market price of a share of Common Stock is the Closing Price of the
Common Stock on the Trading Day immediately preceding the Repurchase Date.

                  (i) Any issuance and delivery of certificates for shares of
Common Stock on repurchase of Securities shall be made without charge to the
Holder of Securities being repurchased for such certificates or for any tax or
duty in respect of the issuance or delivery of such certificates or the
securities represented thereby; PROVIDED, HOWEVER, that the Company shall not be
required to pay any tax or duty which may be payable in respect of (i) income of
the Holder or (ii) any transfer involved in the issuance or delivery of
certificates for shares of Common Stock in a name other than that of the Holder
of the Securities being repurchased, and no such issuance or delivery shall be
made unless and until the Person requesting such issuance or delivery has paid
to the Company the amount of any such tax or duty or has established, to the
satisfaction of the Company, that such tax or duty has been paid.

                  (j) All Securities delivered for repurchase shall be delivered
to the Trustee to be canceled in accordance with the provisions of Section 2.11.

                  (k) The Company may elect to pay the Repurchase Price by
delivery of shares of Common Stock if and only if the following conditions shall
have been satisfied:

                  (i) the shares of Common Stock deliverable in payment of the
         Repurchase Price shall have a fair market value as of the Repurchase
         Date of not less than the Repurchase Price. For purposes of this
         Section 3.07, the fair market value of shares of Common Stock shall be
         determined by the Company and shall be equal to 95% of the average of
         the Closing Prices of the Common Stock for the five consecutive Trading
         Days immediately preceding and including the third Trading Day prior to
         the Repurchase Date;

                 (ii) such shares have been registered under the Securities Act
         or are freely transferable without such registration;

<PAGE>
                                       -21-

                (iii) the issuance of such Common Stock does not require
         registration with or approval of any governmental authority under any
         state law or any other federal law, which registration or approval has
         not been made or obtained;

                 (iv) such shares have been approved for quotation on the Nasdaq
         National Market or listing on a national securities exchange; and

                  (v) such shares will be issued out of the Company's authorized
         but unissued stock and, upon issuance, will be duly and validly and
         fully paid and non-assessable and free of any preemptive rights.

                  (l)  For purposes of this Section 3.07:

                  (i) the term "BENEFICIAL OWNER" shall be determined in
         accordance with Rule 13d-3 and 13d-5, as in effect on the date of the
         original execution of this Indenture, promulgated by the SEC pursuant
         to the Exchange Act;

                 (ii) the term "PERSON" or "GROUP" shall include any syndicate
         or group which would be deemed to be a "person" under Section 13(d) and
         14(d) of the Exchange Act as in effect on the date of this Indenture;

                (iii) the term "CONTINUING DIRECTOR" means at any date a member
         of the Company's Board of Directors (i) who was a member of such board
         on December 13, 2000 or (ii) who was nominated or elected by at least a
         majority of the directors who were Continuing Directors at the time of
         such nomination or election or whose election to the Company's Board of
         Directors was recommended or endorsed by at least a majority of the
         directors who were Continuing Directors at the time of such nomination
         or election or such lesser number comprising a majority of a nominating
         committee if authority for such nominations or elections has been
         delegated to a nominating committee whose authority and composition
         have been approved by at least a majority of the Continuing Directors;
         and

                 (iv) the term "REPURCHASE EVENT" means a Change in Control or a
         Termination of Trading, in each case defined as follows:

                           A "CHANGE IN CONTROL" shall be deemed to have
                  occurred when (i) any "person" or "group" (as such terms are
                  used in Sections 13(d) and 14(d) of the Exchange Act) is or
                  becomes the "beneficial owner" (as defined in Rules 13-d3 and
                  13-d5 under the Exchange Act) of shares representing more than
                  50% of the combined voting power of the then outstanding
                  securities entitled to vote generally in elections of
                  directors of the Company (the "VOTING STOCK"); (ii) the
                  Company is liquidated or dissolved; (iii) the Company (A)
                  consolidates with or merges into any other Person or any other
                  Person merges into the Company, and in the case of any such
                  transaction, the outstanding Common Stock of the Company is
                  changed or exchanged into other assets or securities as a
                  result, unless the stockholders of the Company immediately
                  before such transaction own, directly or indirectly
                  immediately following such trans-

<PAGE>
                                       -22-

                  action, more than 50% of the combined voting power of the
                  outstanding voting securities of the Person resulting from
                  such transaction in substantially the same proportion as
                  their ownership of the Voting Stock immediately before such
                  transaction, or (B) conveys, transfers or leases all or
                  substantially all of its assets to any Person other than a
                  subsidiary or subsidiaries; or (iv) Continuing Directors do
                  not at any time constitute a majority of the Board of
                  Directors of the Company; PROVIDED that a Change in Control
                  shall not be deemed to have occurred if either (x) the
                  Closing Price of the Common Stock for any five (5) Trading
                  Days during the ten (10) Trading Days immediately preceding
                  the Change in Control is at least equal to 105% of the
                  Conversion Price in effect on the date on which the Change
                  in Control occurs or (y) in the case of a merger or
                  consolidation otherwise constituting a Change in Control,
                  all of the consideration (excluding cash payments for
                  fractional shares) in such merger or consolidation
                  constituting the Change in Control consists of common stock
                  traded on a United States national securities exchange or
                  quoted on the Nasdaq National Market (or which will be so
                  traded or quoted when issued or exchanged in connection with
                  such Change in Control) and as a result of such transaction
                  or transactions the Securities become convertible solely
                  into such Common Stock.

                           A "TERMINATION OF TRADING" shall have occurred if the
                  Common Stock (or other common stock into which the Securities
                  are then convertible) is neither listed for trading on a
                  United States national securities exchange nor approved for
                  trading on an established automated over-the-counter trading
                  market in the United States.

                                  ARTICLE FOUR

                                    COVENANTS

SECTION 4.01.         PAYMENT OF SECURITIES.

                  The Company shall pay the principal amount, premium, if any,
of and any accrued and unpaid interest on the Securities on the dates and in the
manner provided in the Securities. The principal, premium, if any, and any
accrued and unpaid interest thereon shall be considered paid on the date due if
the Paying Agent holds (or, if the Company is acting as Paying Agent, if the
Company has segregated and holds in trust in accordance with Section 2.04) on
that date money sufficient to pay the principal, premium, if any, and any
accrued and unpaid interest thereon.

                  The Company shall pay interest on any overdue principal at the
rate borne by the Securities. The Company shall pay interest on overdue
installments of interest at the same rate to the extent not prohibited by
applicable law.

<PAGE>
                                       -23-

SECTION 4.02.         MAINTENANCE OF OFFICE OR AGENCY.

                  The Company will maintain in the Borough of Manhattan, The
City of New York, an office or agency where Securities may be surrendered for
registration of transfer or exchange or conversion and where notices and demands
to or upon the Company in respect of the Securities and this Indenture may be
served. The Company will give prompt written notice to the Trustee of the
location, and any change in the location, of such office or agency. If at any
time the Company shall fail to maintain any such required office or agency or
shall fail to furnish the Trustee with the address thereof, such presentations,
surrenders, notices and demands may be made or served at the Corporate Trust
Office of the Trustee.

                  The Company may also from time to time designate one or more
other offices or agencies where the Securities may be presented or surrendered
for any or all such purposes and may from time to time rescind such
designations; PROVIDED, HOWEVER, that no such designation or rescission shall in
any manner relieve the Company of its obligation to maintain an office or agency
in the Borough of Manhattan, The City of New York for such purposes. The Company
will give prompt written notice to the Trustee of any such designation or
rescission and of any change in the location of any such other office or agency.

                  The Company hereby designates the Corporate Trust Office of
the Trustee as an agency of the Company in accordance with Section 2.03.

                  The Company also shall comply with the provisions of TIA
Section 314(a).

SECTION 4.03.         REPORTS TO HOLDERS.

                  (a) The Company (at its own expense) will deliver to the
Trustee within 15 days after the filing of the same with the SEC, copies of the
quarterly and annual reports and of the information, documents and other
reports, if any, the Company is required to file with the SEC pursuant to
Section 13 or 15(d) of the Exchange Act.

                  (b) Notwithstanding that the Company may not be subject to the
reporting requirements of Section 13 or 15(d) of the Exchange Act, the Company
will promptly provide the information required by Rule 144A(d)(4) to any Holder
that so requests.

                  (c) In addition, if and when this Indenture becomes subject to
the TIA, the Company will file a copy of all such information with the SEC for
public availability (unless the Commission will not accept such a filing) and
make such information available to investors who request it in writing. The
Company will also comply with the other provisions of TIA Section 314(a).

SECTION 4.04.         COMPLIANCE CERTIFICATE.

                  The Company shall deliver to the Trustee within 120 days after
the end of each fiscal year of the Company an Officers' Certificate stating
whether or not the signers know of any Default or Event of Default by the
Company in performing any of its obligations under this Indenture or the

<PAGE>
                                       -24-

Securities. If they do know of any such Default or Event of Default, the
certificate shall describe the Default or Event of Default and its status.

SECTION 4.05.         STAY, EXTENSION AND USURY LAWS.

                  The Company covenants (to the extent that it may lawfully do
so) that it will not at any time insist upon, plead, or in any manner whatsoever
claim or take the benefit or advantage of, any stay, extension or usury law
wherever enacted, now or at any time hereafter in force, which may affect the
covenants or the performance of this Indenture; and the Company (to the extent
that it may lawfully do so) hereby expressly waives all benefit or advantage of
any such law, and covenants that it will not, by resort to any such law, hinder,
delay or impede the execution of any power herein granted to the Trustee, but
will suffer and permit the execution of every such power as though no such law
has been enacted.

SECTION 4.06.         CORPORATE EXISTENCE.

                  Subject to Article Five, the Company will do or cause to be
done all things necessary to preserve and keep in full force and effect its
corporate existence and the corporate existence of each subsidiary in accordance
with the respective organizational documents of each subsidiary and the rights
(charter and statutory), licenses and franchises of the Company and its
subsidiaries; PROVIDED, HOWEVER, that the Company shall not be required to
preserve any such right, license or franchise, or the corporate existence of any
subsidiary, if in the judgment of the Company, (i) such preservation or
existence is not material to the conduct of business of the Company and (ii) the
loss of such right, license or franchise or the dissolution of such subsidiary
does not have a material adverse impact on the Holders.

SECTION 4.07.         NOTICE OF DEFAULT.

                  In the event that any Default under Section 6.01 hereof shall
occur the Company will give prompt written notice of such Default to the
Trustee.

                                  ARTICLE FIVE

                    CONSOLIDATION, MERGER AND SALE OF ASSETS

SECTION 5.01.         WHEN COMPANY MAY MERGE, ETC.

                  The Company shall not consolidate with or merge into, or
transfer or lease all or substantially all of its assets to, another Person
unless such other Person is a corporation, limited liability company,
partnership, trust or other business entity organized under the laws of the
United States, any State thereof or the District of Columbia and such Person
assumes by supplemental indenture all the obligations of the Company under the
Securities, this Indenture and the Registration Rights Agreement, and
immediately after giving effect to the transaction, no Default or Event of
Default has occurred and is continuing.

<PAGE>
                                       -25-

                  The Company shall deliver to the Trustee prior to the
consummation of the proposed transaction an Officers' Certificate to the
foregoing effect and an Opinion of Counsel stating that the proposed transaction
and such supplemental indenture will, upon consummation of the proposed
transaction, comply with this Indenture.

                  Notwithstanding the foregoing, any subsidiary may consolidate
with, merge into or transfer all or part of its properties and assets to the
Company or any other subsidiary or subsidiaries.

SECTION 5.02.         SUCCESSOR SUBSTITUTED.

                  Upon any consolidation or merger or transfer or lease of all
or substantially all of the assets of the Company in accordance with Section
5.01, the successor Person formed by such consolidation or into which the
Company is merged or to which such transfer or lease is made shall succeed to,
and be substituted for, and may exercise every right and power of, and shall
assume every duty and obligation of, the Company under this Indenture with the
same effect as if such successor corporation had been named as the Company
herein. When the successor corporation assumes all obligations of the Company
hereunder, all obligations of the predecessor corporation shall terminate.

                                   ARTICLE SIX

                              DEFAULTS AND REMEDIES

SECTION 6.01.         EVENTS OF DEFAULT.

                  An "EVENT OF DEFAULT" occurs if:

                  (1)      the Company fails to pay the principal of or any
         premium on the Securities when due (whether or not prohibited by the
         provisions set forth in Article Twelve hereof);

                  (2)      the Company fails to pay any interest on the
         Securities for 30 days when due (whether or not prohibited by the
         provisions set forth in Article Twelve hereof);

                  (3)      the Company fails to perform any other covenant in
         this Indenture for the period of 90 days after the notice specified
         in the last paragraph of this Section 6.01;

                  (4)      the Company pursuant to or within the meaning of any
         Bankruptcy Law:

                           (A)      commences a voluntary case,

                           (B)      consents to the entry of an order for relief
                  against it in an involuntary case,

                           (C)      consents to the appointment of a Custodian
                  of it or for all or substantially all of its property, or

<PAGE>
                                       -26-

                           (D)      makes a general assignment for the benefit
                  of its creditors; or

                  (5)      a court of competent jurisdiction enters an order or
         decree under any Bankruptcy Law that:

                           (A)      is for relief against the Company in an
                  involuntary case,

                           (B)      appoints a Custodian of the Company for all
                  or substantially all of its property, or

                           (C)      orders the liquidation of the Company,

         and the order or decree remains unstayed and in effect for 90
         consecutive days.

                  The term "BANKRUPTCY LAW" means Title 11, U.S. Code or any
similar Federal or State law for the relief of debtors. The term "CUSTODIAN"
means any receiver trustee, assignee, liquidator or similar official under any
Bankruptcy Law.

                  A default under clause (3) is not an Event of Default until
the Trustee or the Holders of at least 25% in aggregate principal amount of the
Securities then outstanding notify the Company and the Trustee of the default
and the Company does not cure the default within 90 days after receipt of the
notice of such default. The notice must specify the default, demand that it be
remedied and state that the notice is a "Notice of Default". If the Holders of
25% in aggregate principal amount of the outstanding Securities request the
Trustee to give such notice on their behalf, the Trustee shall do so. When a
default is cured, it ceases.

SECTION 6.02.         ACCELERATION.

                  If an Event of Default (other than an Event of Default
specified in Section 6.01(4) or (5)) occurs and is continuing, the Trustee by
notice to the Company, or the Holders of at least 25% in principal amount of the
Securities then outstanding by notice to the Company and the Trustee, may
declare the principal of, premium, if any, and any accrued and unpaid interest
on all the Securities to be due and payable. Upon such declaration such
principal and interest shall be due and payable immediately. If an Event of
Default specified in Section 6.01(4) or (5) occurs, the entire principal amount
of the Securities shall IPSO FACTO become and be immediately due and payable
without any declaration or other act on the part of the Trustee or any Holder.

                  The Company shall promptly notify holders of Designated Senior
Indebtedness if payment of the Securities is accelerated because of an Event of
Default. Any payments by the Company on the Securities following any such
accelerating will be subject to the subordination provisions of Article Twelve
to the extent provided therein.

                  After a declaration of acceleration, but before a judgment or
decree of the money due in respect of the Securities has been obtained, the
Holders of not less than a majority in aggregate principal amount of the
Securities then outstanding by written notice to the Trustee may rescind an
acceleration and its consequences if (i) all existing Events of Default (other
than the nonpayment of

<PAGE>
                                       -27-

principal of and interest on the Securities which has become due solely by
virtue of such acceleration) have been cured or waived, (ii) the rescission
would not conflict with any judgment or decree and (iii) the Company shall have
paid all amounts due pursuant to Section 7.07.

SECTION 6.03.         OTHER REMEDIES.

                  Notwithstanding any other provision of this Indenture, if an
Event of Default occurs and is continuing, the Trustee may pursue any available
remedy by proceeding at law or in equity to collect the payment of the principal
of, premium, if any, and interest on the Securities or to enforce the
performance of any provision of the Securities or this Indenture.

                  The Trustee may maintain a proceeding even if it does not
possess any of the Securities or does not produce any of them in the proceeding.
A delay or omission by the Trustee or any Holder in exercising any right or
remedy accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. All remedies are
cumulative.

SECTION 6.04.         WAIVER OF PAST DEFAULTS.

                  Subject to Sections 6.02, 6.07 and 9.02, the Holders of a
majority in aggregate principal amount of the Securities then outstanding by
notice to the Trustee may waive any past Default or Event of Default and its
consequences. When a Default or an Event of Default is waived, it is cured and
ceases.

SECTION 6.05.         CONTROL BY MAJORITY.

                  The Holders of a majority in aggregate principal amount of the
Securities then outstanding may direct the time, method and place of conducting
any proceeding for any remedy available to the Trustee or exercising any trust
or power conferred on it. However, the Trustee may refuse to follow any
direction that conflicts with law or this Indenture, is unduly prejudicial to
the rights of other Holders or would involve the Trustee in personal liability;
PROVIDED that the Trustee may take any other action reasonably deemed proper by
the Trustee which is not inconsistent with such direction.

SECTION 6.06.         LIMITATION ON SUITS.

                  Except as provided in Section 6.07, a Holder may pursue a
remedy with respect to this Indenture or the Securities only if:

                  (1)      the Holder gives to the Trustee written notice of a
         continuing Event of Default;

                  (2)      the Holders of at least 25% in aggregate principal
         amount of the Securities then outstanding make a written request to
         the Trustee to pursue the remedy;

<PAGE>
                                       -28-

                  (3)      such Holder or Holders offer to the Trustee
         reasonable indemnity against any loss, liability or expense;

                  (4)      the Trustee does not comply with the request within
         60 days after receipt of the request and the offer of indemnity; and

                  (5)      during such 60-day period the Holders of a majority
         in aggregate principal amount of the Securities then outstanding do
         not give the Trustee a direction inconsistent with the request.

                  A Holder may not use this Indenture to prejudice the rights of
another Holder or to obtain a preference or priority over another Holder.

SECTION 6.07.         RIGHTS OF HOLDERS TO RECEIVE PAYMENT OR CONVERT.

                  Notwithstanding any other provision of this Indenture, (i) the
right of any Holder to receive payment of the principal of and interest on the
Security, on or after the respective due dates expressed in the Security, or to
bring suit for the enforcement of any such payment on or after such respective
dates, shall not be impaired or affected without the consent of the Holder and
(ii) the right of any Holder to bring suit for the enforcement of the right to
convert the Security shall not be impaired or affected without the consent of
the Holder.

SECTION 6.08.         COLLECTION SUIT BY TRUSTEE.

                  If an Event of Default specified in Section 6.01(l) or (2)
occurs and is continuing, the Trustee may recover judgment in its own name and
as trustee of an express trust against the Company for the whole amount of
principal and interest remaining unpaid and amounts due to the Trustee under
Section 7.07.

SECTION 6.09.         TRUSTEE MAY FILE PROOFS OF CLAIM.

                  The Trustee may file such proofs of claim and other papers or
documents as may be necessary or advisable in order to have the claims of the
Trustee, any predecessor Trustee and the Holders allowed in any judicial
proceedings relative to the Company, its creditors or its property.

                  Nothing herein contained shall be deemed to authorize the
Trustee to authorize or consent to or accept or adopt on behalf of any Holder
any plan of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof, or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding.

SECTION 6.10.         PRIORITIES.

                  If the Trustee collects any money pursuant to this Article, it
shall pay out the money in the following order:

                  FIRST:  to the Trustee for amounts due under Section 7.07;

<PAGE>
                                       -29-

                  SECOND:  to holders of Senior Indebtedness to the extent
         required by Article Twelve;

                  THIRD:  to Holders for amounts due and unpaid on the
         Securities for principal, premium, if any, and interest, ratably,
         without preference or priority of any kind, according to the amounts
         due and payable on the Securities for principal, premium, if any, and
         interest, respectively; and

                  FOURTH:  to the Company.

                  The Trustee, upon prior written notice to the Company, may fix
a record date and payment date for any payment by it to Holders pursuant to this
Section 6.10.

SECTION 6.11.         UNDERTAKING FOR COSTS.

                  In any suit for the enforcement of any right or remedy under
this Indenture or in any suit against the Trustee for any action taken or
omitted by it as Trustee, a court in its discretion may require the filing by
any party litigant in the suit other than the Trustee of an undertaking to pay
the costs of the suit, and the court in its discretion may assess reasonable
costs, including reasonable attorneys' fees, against any party litigant in the
suit, having due regard to the merits and good faith of the claims or defenses
made by the party litigant. This Section 6.11 shall not apply to a suit by the
Trustee, a suit by a Holder or group of Holders of more than 10% in aggregate
principal amount of the outstanding Securities, or to any suit instituted by any
Holder for the enforcement or the payment of the principal or interest on any
Securities on or after the respective due dates for such Securities.

                                  ARTICLE SEVEN

                                     TRUSTEE

SECTION 7.01.         DUTIES OF TRUSTEE.

                  (a) If an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in their exercise, as a
prudent person would exercise or use under the circumstances in the conduct of
his or her own affairs.

                  (b) Except during the continuance of an Event of Default:

                  (1) the Trustee need perform only those duties that are
         specifically set forth in this Indenture and no others and no implied
         covenants or obligations shall be read into this Indenture against the
         Trustee; and

                  (2) in the absence of bad faith on its part, the Trustee may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon certificates or
         opinions furnished to the Trustee and conforming to the requirements of
         this Inden-

<PAGE>
                                       -30-

         ture, but in the case of any such certificates or opinions which by
         any provision hereof are specifically required to be furnished to the
         Trustee, the Trustee shall examine the certificates and opinions to
         determine whether or not they conform to the requirements of this
         Indenture.

                  (c) The Trustee may not be relieved from liability for its own
negligent action, its own negligent failure to act or its own willful
misconduct, except that:

                  (1) this paragraph does not limit the effect of paragraph (b)
         of this Section 7.01;

                  (2) the Trustee shall not be liable for any error of judgment
         made in good faith by a Trust Officer, unless it is proved that the
         Trustee was negligent in ascertaining the pertinent facts; and

                  (3) the Trustee shall not be liable with respect to any action
         it takes or omits to take in good faith in accordance with a direction
         received by it pursuant to Section 6.05.

                  (d) The Trustee may refuse to perform any duty or exercise any
right or power unless it receives indemnity satisfactory to it against any loss,
liability or expense.

                  (e) The Trustee shall not be liable for interest on any money
received by it except as the Trustee may agree in writing with the Company.
Money held in trust by the Trustee need not be segregated from other funds
except to the extent required by law.

                  (f) No provision of this Indenture shall require the Trustee
to expend or risk its own funds or otherwise incur any financial liability in
the performance of any of its duties hereunder, or in the exercise of any of its
rights and powers.

                  (g) Whether or not expressly provided, every provision of this
Indenture relating to the conduct or affecting the liability of or affording
protection to the Trustee shall be subject to the provisions of this Article
Seven and apply to the Trustee in its capacity as Registrar, Paying Agent and
Conversion Agent.

SECTION 7.02.         RIGHTS OF TRUSTEE.

                  (a) The Trustee may rely on any document reasonably believed
by it to be genuine and to have been signed or presented by the proper person.
The Trustee need not investigate any fact or matter stated in the document; if,
however, the Trustee shall determine to make such further inquiry or
investigation, it shall be entitled to examine the books, records and premises
of the Company, personally or by agent or attorney.

                  (b) Before the Trustee acts or refrains from acting, it may
require an Officers' Certificate and/or an Opinion of Counsel. The Trustee shall
not be liable for any action it takes or omits to take in good faith in reliance
on such Officers' Certificate or Opinion of Counsel.

<PAGE>
                                       -31-

                  (c) Any request or direction of the Company mentioned herein
shall be sufficiently evidenced by a Company Request or Company Order and any
resolution of the Board of Directors shall be sufficiently evidenced by a Board
Resolution.

                  (d) The Trustee may consult with counsel (such counsel to be
reasonably acceptable to the Company) and the written advice of such counsel or
any Opinion of Counsel shall be full and complete authorization and protection
in respect of any action taken, suffered or omitted by it hereunder in good
faith and in reliance thereon and in accordance with the advice or Opinion of
Counsel, PROVIDED, HOWEVER, that this provision shall not protect the Trustee
from liability for its own gross negligence or willful misconduct.

                  (e) The Trustee may act through agents or attorneys and shall
not be responsible for the misconduct or negligence of any agent or attorney
appointed with due care.

                  (f) The Trustee shall not be liable for any action it takes or
omits to take in good faith which it reasonably believes to be authorized or
within its discretion, rights or powers hereunder.

                  (g) Whenever in the administration of this Indenture the
Trustee shall deem it desirable that a matter be proved or established prior to
taking, suffering or omitting any action hereunder, the Trustee may, in absence
of bad faith on its part, rely upon an Officers' Certificate.

                  (h) The Trustee shall be under no obligation to exercise any
of the rights or powers vested in it by this Indenture at the request or
direction of any of the Holders, unless such Holders shall have offered to the
Trustee reasonable security or indemnity against costs, expenses and liabilities
that might be incurred by it in compliance with such request or direction.

                  (i) The Trustee shall not be charged with knowledge of any
Default or Event of Default with respect to the Securities unless either (1) a
Trust Officer shall have actual knowledge of such Default or Event of Default or
(2) written notice of such Default or Event of Default shall have been given to
the Trustee by the Company or by any Holder.

                  (j)  The right of the Trustee to perform any discretionary
act hereunder shall not be construed as a duty.

SECTION 7.03.         INDIVIDUAL RIGHTS OF TRUSTEE.

                  The Trustee in its individual or any other capacity may become
the owner or pledgee of Securities and may otherwise deal with the Company or an
Affiliate thereof with the same rights it would have if it were not Trustee. Any
Agent may do the same with like rights. The Trustee, however, must comply with
Sections 7.10 and 7.11.

SECTION 7.04.         TRUSTEE'S DISCLAIMER.

                  The Trustee makes no representation as to the validity or
adequacy of this Indenture or the Securities; it shall not be accountable for
the Company's use of the proceeds from the Securi-

<PAGE>
                                       -32-

ties; and it shall not be responsible for any statement in the Securities other
than its certificate of authentication.

SECTION 7.05.         NOTICE OF DEFAULTS.

                  If a Default or Event of Default occurs and is continuing and
if it is actually known to the Trustee, the Trustee shall mail to each Holder a
notice of the Default or Event of Default within 30 days after it occurs unless
such Default or Event of Default has been cured or waived. Except in the case of
a Default or Event of Default in payment of the principal of, premium, if any,
and interest on any Security, the Trustee may withhold the notice if and so long
as it in good faith determines that withholding the notice is in the interests
of Holders.

SECTION 7.06.         REPORTS BY TRUSTEE TO HOLDERS.

                  Within 60 days after each December 15 beginning with
December 15, 2001, the Trustee shall mail to each Holder, to the extent
required by TIA Section 313(c), a brief report dated as of such reporting
date that complies with TIA Section 313(a). In such event, the Trustee also
shall comply with TIA Section 313(b).

                  A copy of each report at the time of its mailing to Holders
shall be mailed to the Company and filed by the Trustee with the SEC and each
stock exchange, if any, on which the Securities are listed. The Company shall
promptly notify the Trustee when the Securities are listed on any stock
exchange.

SECTION 7.07.         COMPENSATION AND INDEMNITY.

                  The Company shall pay to the Trustee from time to time such
compensation for its services as shall be agreed upon in writing. The Trustee's
compensation shall not be limited by any law on compensation of a trustee of an
express trust. The Company shall reimburse the Trustee upon request for all
reasonable out-of-pocket expenses incurred by it. Such expenses shall include
the reasonable compensation and out-of-pocket expenses of the Trustee's agents
and counsel.

                  The Company shall indemnify the Trustee, its officers,
employees, successors and assigns against any loss or liability or expense
(including the reasonable fees and expenses of counsel) incurred by it in
connection with the acceptance or administration of this trust and the
performance of its duties hereunder, including the reasonable costs and expenses
of defending itself against any claim or liability in connection with the
exercise or performance of any of its powers and duties hereunder. The Company
need not pay for any settlement made without its consent. The Trustee shall
notify the Company promptly of any claim for which it may seek indemnification.
The Company need not reimburse any expense or indemnify against any loss or
liability incurred by the Trustee through the Trustee's negligence or bad faith.

                  To secure the Company's payment obligations in this Section
7.07, the Trustee shall have a lien prior to the Securities on all money or
property held or collected by the Trustee, except that held in trust to pay the
principal of, premium, if any, and interest on particular Securities.

<PAGE>
                                       -33-

                  The indemnity obligations of the Company with respect to the
Trustee provided for in this Section 7.07 shall survive any resignation or
removal of the Trustee and the termination of this Indenture.

                  When the Trustee incurs expenses or renders services after an
Event of Default specified in Section 6.01(4) or (5) occurs, the expenses and
the compensation for the services are intended to constitute expenses of
administration under any Bankruptcy Law.

SECTION 7.08.         REPLACEMENT OF TRUSTEE.

                  A resignation or removal of the Trustee and appointment of a
successor Trustee shall become effective only upon the successor Trustee's
acceptance of appointment as provided in this Section 7.08.

                  The Trustee may resign by so notifying the Company in writing
30 days prior to such resignation. The Holders of a majority in aggregate
principal amount of the Securities then outstanding may remove the Trustee by so
notifying the Trustee and the Company in writing and may appoint a successor
Trustee with the Company's consent. The Company may remove the Trustee if:

                  (1)      the Trustee fails to comply with Section 7.10;

                  (2)      the Trustee is adjudged a bankrupt or an insolvent;

                  (3)      a receiver or other public officer takes charge of
        the Trustee or its property; or

                  (4)      the Trustee becomes incapable of acting.

                  If the Trustee resigns or is removed or if a vacancy exists in
the office of Trustee for any reason, the Company shall promptly appoint a
successor Trustee. Within one year after the successor Trustee takes office, the
Holders of a majority in aggregate principal amount of the Securities then
outstanding may appoint a successor Trustee to replace the successor Trustee
appointed by the Company.

                  If a successor Trustee does not take office within 30 days
after the retiring Trustee resigns or is removed, the retiring Trustee, the
Company or the Holders of at least 10% in aggregate principal amount of the
outstanding Securities may petition any court of competent jurisdiction for the
appointment of a successor Trustee.

                  If the Trustee fails to comply with Section 7.10, any Holder
may petition any court of competent jurisdiction for the removal of the Trustee
and the appointment of a successor Trustee.

                  A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company. Thereupon the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under this Indenture. The successor Trustee shall mail a notice of its
succession to Holders. The re-

<PAGE>
                                       -34-

tiring Trustee shall promptly transfer all property held by it as Trustee to the
successor Trustee, subject to the lien provided for in Section 7.07.

SECTION 7.09.         SUCCESSOR TRUSTEE BY MERGER, ETC.

                  If the Trustee consolidates with, merges or converts into, or
transfers, by sale or otherwise, all or substantially all of its corporate trust
business to, another corporation, the successor corporation without any further
act shall be the successor Trustee, if such successor corporation is otherwise
eligible hereunder.

SECTION 7.10.         ELIGIBILITY; DISQUALIFICATION.

This Indenture shall always have a Trustee who satisfies the requirements of
TIA Section 310(a)(1). The Trustee shall always have (or in the case of a
bank or trust company which is a member of a bank holding company system, the
related bank holding company shall have) a combined capital and surplus of at
least $50,000,000 as set forth in its most recent published annual report of
condition. The Trustee shall comply with TIA Section 310(b).

SECTION 7.11.         PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.

                  The Trustee shall comply with TIA Section 311(a), excluding
any creditor relationship listed in TIA Section 311(b). A Trustee who has
resigned or been removed shall be subject to TIA Section 311(a) to the extent
indicated.

                                  ARTICLE EIGHT

                     SATISFACTION AND DISCHARGE; DEFEASANCE

SECTION 8.01.         TERMINATION OF COMPANY'S OBLIGATIONS.

                  The Company may terminate its substantive obligations in
respect of the Securities if the Securities mature within six months, or all of
them are to be called for redemption within one year under arrangements
satisfactory to the Trustee for giving notice of redemption, by delivering all
outstanding Securities to the Trustee for cancellation and paying all sums
payable by it on account of principal of, premium, if any, and interest on all
Securities or otherwise. In addition to the foregoing, the Company may terminate
its obligations under Sections 3.07, 4.03 and 4.06 (other than with respect to
the corporate existence of the Company), and no Default or Event of Default
under Section 6.01(3) shall thereafter apply, by (i) depositing with the
Trustee, under the terms of an irrevocable trust agreement, money or direct
non-callable obligations of the United States of America for the payment of
which the full faith and credit of the United States is pledged ("U. S.
GOVERNMENT OBLIGATIONS") sufficient (without reinvestment) to pay the principal
of, premium, if any, and interest on the Securities at maturity or an earlier
redemption, (ii) delivering to the Trustee either an Opinion of Counsel or a
ruling directed to the Trustee from the Internal Revenue Service to the effect
that the Holders of the Securities will not recognize income, gain or loss for
federal income tax purposes as a result of such deposit and termination of
obligations and (iii) delivering to the Trustee an Officers'

<PAGE>
                                       -35-

Certificate and an Opinion of Counsel each stating compliance with all
conditions precedent provided for herein. In addition, the Company may, provided
that no Default or Event of Default has occurred and is continuing or would
arise therefrom (or, with respect to a Default or Event of Default specified in
Section 6.01(4), occurs at any time on or prior to the 91st calendar day after
the date of such deposit (it being understood that this condition shall not be
deemed satisfied until after such 91st day)), terminate all of its substantive
obligations in respect of the Securities (including its obligations to pay the
principal of, premium, if any, and interest on the Securities) by (i) depositing
with the Trustee, under the terms of an irrevocable trust agreement, money or
United States Government Obligations sufficient (without reinvestment) to pay
the principal of, premium, if any, and interest on the Securities at maturity or
on earlier redemption, (ii) delivering to the Trustee either a ruling directed
to the Trustee from the Internal Revenue Service to the effect that the Holders
of the Securities will not recognize income, gain or loss for federal income tax
purposes as a result of such deposit and termination of obligations or an
Opinion of Counsel addressed to the Trustee based upon such a ruling or based on
a change in the applicable Federal tax law since the date of this Indenture to
such effect and (iii) delivering to the Trustee an Officers' Certificate and an
Opinion of Counsel each stating compliance with all conditions precedent
provided for herein.

                  Notwithstanding the foregoing paragraph, the Company's
obligations in Article Ten and Sections 2.02, 2.03, 2.04, 2.05, 2.06, 2.07,
2.10, 2.12, 2.13 and 4.01 (but not with respect to termination of substantive
obligations pursuant to the third sentence of the foregoing paragraph), 4.02,
7.07, 7.08, 8.03 and 8.04 shall survive until the Securities are no longer
outstanding. Thereafter the Company's obligations in Sections 7.07, 8.03 and
8.04 shall survive.

                  After such delivery or irrevocable deposit and delivery of an
Officers' Certificate and Opinion of Counsel, the Trustee upon request shall
acknowledge in writing the discharge of the Company's obligations under the
Securities and this Indenture except for those surviving obligations specified
above.

                  The Company shall pay and indemnify the Trustee against any
tax, fee or other charge imposed on or assessed against the United States
Government Obligations deposited pursuant to this Section 8.01 or the principal
and interest received in respect thereof other than any such tax, fee or other
charge which by law is for the account of the Holders of outstanding Securities.

SECTION 8.02.         APPLICATION OF TRUST MONEY.

                  Subject to the provisions of Section 8.03, the Trustee shall
hold in trust money or U.S. Government Obligations deposited with it pursuant to
Section 8.01. It shall apply the deposited money and the money from U.S.
Government obligations through the Paying Agent and in accordance with this
Indenture to the payment of the principal of, premium, if any, and interest on
the Securities. Money and securities so held in trust are not subject to the
subordination provisions of Article Twelve.

<PAGE>
                                       -36-

SECTION 8.03.         REPAYMENT TO COMPANY.

                  The Trustee and the Paying Agent shall promptly pay to the
Company upon request any excess money or securities held by them at any time.
The Trustee and the Paying Agent shall pay to the Company upon request any money
held by them for the payment of the principal of, premium, if any, and interest
that remains unclaimed for a period ending on the earlier of the date that is
ten (10) Business Days prior to the date such money would escheat to the state
or two years after such principal, premium, if any, and interest became due and
payable; PROVIDED, HOWEVER, that the Trustee or such Paying Agent, before being
required to make any such repayment, may, at the expense of the Company, cause
to be published once in a newspaper of general circulation in The City of New
York or cause to be mailed to each Holder, notice stating that such money
remains and that, after a date specified therein, which shall not be less than
30 days from the date of such publication or mailing, any unclaimed balance of
such money then remaining will be repaid to the Company. After payment to the
Company, Holders entitled to the money must look to the Company for payment as
general creditors unless an applicable abandoned property law designates another
Person.

SECTION 8.04.         REINSTATEMENT.

                  If the Trustee or Paying Agent is unable to apply any money or
U.S. Government Obligations in accordance with Section 8.01 by reason of any
legal proceeding or by reason of any order or judgment of any court or
governmental authority enjoining, restraining or otherwise prohibiting such
application, the Company's obligations under this Indenture and the Securities
shall be revived and reinstated as though no deposit had occurred pursuant to
Section 8.01 until such time as the Trustee or Paying Agent is permitted to
apply all such money or U.S. Government Obligations in accordance with Section
8.01; PROVIDED, HOWEVER, that to the extent the Company makes any payment of the
principal of, premium, if any, and interest on any Securities because of the
reinstatement of its obligations, the Company shall be subrogated to the rights
of the Holders of such Securities to receive such payment from the money or U.S.
Government Obligations held by the Trustee or Paying Agent.

                                  ARTICLE NINE

                                   AMENDMENTS

SECTION 9.01.         WITHOUT CONSENT OF HOLDERS.

                  The Company, when authorized by a Board Resolution, may
modify, amend or supplement this Indenture or the Securities without notice to
or the consent of any Holder:

                  (1)      to cure any ambiguity, omission, defect or
        inconsistency;

                  (2)      to comply with Sections 5.01 and 10.07;

                  (3)      to provide for uncertificated Securities in addition
        to certificated Securities; or

<PAGE>
                                       -37-

                  (4)      to make any change that does not adversely affect the
        rights of any Holder.

SECTION 9.02.         WITH CONSENT OF HOLDERS.

                  The Company, when authorized by a Board Resolution, may
modify, amend or supplement this Indenture or the Securities without notice to
any Holder but with the written consent of the Holders of at least a majority in
aggregate principal amount of the outstanding Securities. Subject to Section
6.07, the Holders of a majority in aggregate principal amount of the outstanding
Securities may waive compliance by the Company with any provision of this
Indenture or the Securities without notice to any other Holder. However, without
the consent of each Holder affected, an amendment, supplement or waiver,
including a waiver pursuant to Section 6.04, may not:

                  (1)      change the stated maturity of the Securities;

                  (2)      reduce the principal, premium, if any, or interest
         on the Securities;

                  (3)      change the place of payment from New York, New York
         or change the currency in which the Securities are payable;

                  (4)      waive a default in the payment of the principal of,
         premium, if any, or interest on any Security;

                  (5)      make any change in Section 6.04, Section 6.07 or
         this Section 9.02;

                  (6)      modify the provisions of Article Twelve in a
         materially adverse manner to the Holders; or

                  (7)      make any change that adversely affects the right to
         convert any Security.

                  Furthermore, an amendment under this Article Nine may not make
any change that adversely affects the rights of any holder of Senior
Indebtedness under Article Twelve unless the holders of such Senior Indebtedness
consent to such change pursuant to the terms governing such Senior Indebtedness.
It shall not be necessary for the consent of the Holders under this Section 9.02
to approve the particular form of any proposed amendment or supplement, but it
shall be sufficient if such consent approves the substance thereof.

                  Promptly after an amendment under this Section 9.02 becomes
effective, the Company shall mail to Holders a notice briefly describing the
amendment.

SECTION 9.03.         COMPLIANCE WITH TRUST INDENTURE ACT.

                  Every amendment, waiver or supplement to this Indenture or the
Securities shall comply with the TIA as then in effect.

<PAGE>
                                       -38-

SECTION 9.04.         REVOCATION AND EFFECT OF CONSENTS.

                  Until an amendment, supplement or waiver becomes effective, a
consent to it by a Holder is a continuing consent by the Holder and every
subsequent Holder of a Security or portion of a Security that evidences the same
debt as the consenting Holder's Security, even if notation of the consent is not
made on any Security. However, any such Holder or subsequent Holder may revoke
the consent as to its Security or portion of a Security if the Trustee receives
the notice of revocation before the date the amendment, supplement or waiver
becomes effective. An amendment, supplement or waiver becomes effective in
accordance with its terms and thereafter binds every Holder.

                  After an amendment, supplement or waiver becomes effective
with respect to the Securities, it shall bind every Holder unless it makes a
change described in any of clauses (1) through (7) of Section 9.02. In that case
the amendment, supplement or waiver shall bind each Holder of a Security who has
consented to it and, provided that notice of such amendment, supplement or
waiver is reflected on a Security that evidences the same debt as the consenting
Holder's Security, every subsequent Holder of a Security or portion of a
Security that evidences the same debt as the consenting Holder's Security.

SECTION 9.05.         NOTATION ON OR EXCHANGE OF SECURITIES.

                  If an amendment, supplement or waiver changes the terms of a
Security, the Trustee may require the Holder of the Security to deliver it to
the Trustee. The Trustee may place an appropriate notation on the Security as
directed and prepared by the Company about the changed terms and return it to
the Holder. Alternatively, if the Company so determines, the Company in exchange
for the Security shall issue and the Trustee shall authenticate a new Security
that reflects the changed terms.

SECTION 9.06.         TRUSTEE PROTECTED.

                  The Trustee need not sign any amendment, supplement or waiver
authorized pursuant to this Article that adversely affects the Trustee's rights.
The Trustee shall be entitled to receive and rely upon, in addition to the
documents required by Section 13.04, an Opinion of Counsel and an Officers'
Certificate that any supplemental indenture, modification, amendment or waiver
complies with the Indenture.

                                   ARTICLE TEN

                                   CONVERSION

SECTION 10.01.        CONVERSION PRIVILEGE; RESTRICTIVE LEGENDS.

                  A Holder of a Security may convert the principal of such
Security into Common Stock at any time during the period stated in paragraph 9
of the Securities. The number of shares issuable upon conversion of a Security
is determined as follows: divide each $1,000 of the principal amount to be
converted by the Conversion Price in effect on the conversion date and round the
result

<PAGE>
                                       -39-

to the nearest 1/100th of a share. The Conversion Price is subject to
adjustment in accordance with Section 10.06.

                  A Holder may convert a portion of the principal of such
Security if the portion is at least $1,000 principal amount or a whole multiple
of $1,000 principal amount. Provisions of this Indenture that apply to
conversion of all of a Security also apply to conversion of a portion of it.

                  Any shares issued upon conversion of a Security shall bear the
Private Placement Legend set forth in Exhibit B(I) until after the second
anniversary of the later of the Issue Date for such Security and the last date
on which the Company or any Affiliate of the Company was the owner of such
shares or the Security (or any predecessor security) from which such shares were
converted (or such shorter period of time as permitted by Rule 144(k) under the
Securities Act or any successor provision thereunder or such longer period of
time as may be required under the Securities Act or applicable state securities
laws unless otherwise agreed by the Company and the Holder thereof).

SECTION 10.02.        CONVERSION PROCEDURE.

                  To convert a Security a Holder must satisfy the requirements
in paragraph 9 of the Securities. The date on which the Holder satisfies all
those requirements is the conversion date. As soon as practicable, the Company
shall deliver to the Holder through the Conversion Agent a certificate for the
number of full shares of Common Stock issuable upon the conversion and a check
in lieu of any fractional share. The Person in whose name the certificate is
registered shall be treated as a stockholder of record on and after the
conversion date.

                  Except as described below, no payment or adjustment will be
made for accrued interest on, or liquidated damages with respect to, a converted
Security or for dividends on any Common Stock issued on conversion. If any
Security is converted between a record date for the payment of interest and the
next succeeding interest payment date, unless such Security has been called for
redemption on a redemption date between such dates, such Security must be
accompanied by funds equal to the interest payable to the registered Holder on
such interest payment date on the principal amount so converted. A Security
converted on an interest payment date need not be accompanied by any payment,
and the interest on the principal amount of the Security being converted will be
paid on such interest payment date to the registered Holder of such Security on
the applicable record date.

                  If a Holder converts more than one Security at the same time,
the number of full shares issuable upon the conversion shall be based on the
total principal amount of the Securities converted.

                  Upon surrender of a Security that is converted in part the
Trustee shall authenticate for the Holder a new Security equal in principal
amount to the unconverted portion of the Security surrendered.

                  If the last day on which a Security may be converted is a
Legal Holiday in a place where a Conversion Agent is located, the Security may
be surrendered to that Conversion Agent on the next succeeding day that is not a
Legal Holiday.

<PAGE>
                                       -40-

SECTION 10.03.        FRACTIONAL SHARES.

                  The Company will not issue fractional shares of Common Stock
upon conversion of Securities and instead will deliver a check in lieu of the
fractional share based upon the current market value of the Common Stock. The
current market value of a fraction of a share is determined by multiplying the
current market price of a full share by the fraction, and rounding the result to
the nearest cent. For purposes of this Section, the current market price of a
share of Common Stock is the Closing Price of the Common Stock on the Trading
Day immediately preceding the conversion date.

SECTION 10.04.        TAXES ON CONVERSION.

                  If a Holder converts its Security, the Company shall pay any
documentary, stamp or similar issue or transfer tax due on the issue of shares
of Common Stock upon the conversion. However, the Holder shall pay any such tax
which is due because the shares are issued in a name other than the Holder's
name.

SECTION 10.05.        COMPANY TO PROVIDE STOCK.

                  The Company shall reserve out of its authorized but unissued
Common Stock or its Common Stock held in treasury enough shares of Common Stock
to permit the conversion of all of the Securities, including such greater number
of shares of Common Stock into which such Securities shall be convertible into
as a result of a Conversion Price adjustment contemplated by Section 10.06
hereof.

                  All shares of Common Stock which may be issued upon conversion
of the Securities shall be validly issued, fully paid and non-assessable.

                  The Company will endeavor to comply with all securities laws
regulating the offer and delivery of shares of Common Stock upon conversion of
Securities and will endeavor to list such shares on each national securities
exchange on which the Common Stock is listed.

SECTION 10.06.        ADJUSTMENT OF CONVERSION PRICE.

                  The Conversion Price shall be adjusted from time to time by
the Company as follows:

                  (a) In case the Company shall hereafter pay a dividend or make
         a distribution to all holders of the outstanding Common Stock in shares
         of Common Stock, the Conversion Price in effect at the opening of
         business on the date following the Record Date with respect to
         stockholders entitled to receive such dividend or other distribution
         shall be reduced by multiplying such Conversion Price by a fraction of
         which the numerator shall be the number of shares of Common Stock
         outstanding at the close of business on the Record Date fixed for such
         determination and the denominator shall be the sum of such number of
         shares and the total number of shares constituting such dividend or
         other distribution, such reduction to become effective immediately
         after the opening of business on the day following the Record Date. If
         any dividend or distribution of the type described in this Section
         10.06(a) is declared

<PAGE>
                                       -41-

         but not so paid or made, the Conversion Price shall again be adjusted
         to the Conversion Price which would then be in effect if such dividend
         or distribution had not been declared.

                  (b) In case the Company shall issue rights or warrants to all
         holders of its outstanding shares of Common Stock entitling them to
         subscribe for or purchase shares of Common Stock at a price per share
         less than the Current Market Price on the Record Date fixed for the
         determination of stockholders entitled to receive such rights or
         warrants, the Conversion Price shall be adjusted so that the same shall
         equal the price determined by multiplying the Conversion Price in
         effect at the opening of business on the date after such Record Date by
         a fraction of which the numerator shall be the number of shares of
         Common Stock outstanding at the close of business on the Record Date
         plus the number of shares which the aggregate offering price of the
         total number of shares so offered for subscription or purchase would
         purchase at such Current Market Price, and of which the denominator
         shall be the number of shares of Common Stock outstanding on the close
         of business on the Record Date plus the total number of additional
         shares of Common Stock so offered for subscription or purchase. Such
         adjustment shall become effective immediately after the opening of
         business on the day following the Record Date fixed for determination
         of stockholders entitled to receive such rights or warrants. To the
         extent that shares of Common Stock are not delivered pursuant to such
         rights or warrants, upon the expiration or termination of such rights
         or warrants the Conversion Price shall be readjusted to the Conversion
         Price which would then be in effect had the adjustments made upon the
         issuance of such rights or warrants been made on the basis of delivery
         of only the number of shares of Common Stock actually delivered. In the
         event that such rights or warrants are not so issued, the Conversion
         Price shall again be adjusted to be the Conversion Price which would
         then be in effect if such date fixed for the determination of
         stockholders entitled to receive such rights or warrants had not been
         fixed. In determining whether any rights or warrants entitle the
         holders to subscribe for or purchase shares of Common Stock at less
         than such Current Market Price, and in determining the aggregate
         offering price of such shares of Common Stock, there shall be taken
         into account any consideration received for such rights or warrants,
         the value of such consideration, if other than cash, to be determined
         in good faith by the Board of Directors.

                  (c) In case the outstanding shares of Common Stock shall be
         split or subdivided into a greater number of shares of Common Stock,
         the Conversion Price in effect at the opening of business on the day
         following the day upon which such subdivision becomes effective shall
         be proportionately reduced, and conversely, in case outstanding shares
         of Common Stock shall be combined into a smaller number of shares of
         Common Stock, the Conversion Price in effect at the opening of business
         on the day following the day upon which such combination becomes
         effective shall be proportionately increased, such reduction or
         increase, as the case may be, to become effective immediately after the
         opening of business on the day following the day upon which such
         subdivision or combination becomes effective.

                  (d) In case the Company shall, by dividend or otherwise,
         distribute to all holders of its Common Stock shares of any class of
         capital stock of the Company (other than any dividends or distributions
         to which Section 10.06(a) applies) or evidences of its indebtedness,
         cash or other assets (including securities, but excluding (1) any
         rights or warrants referred to

<PAGE>
                                       -42-

         in Section 10.06(b), (2) dividends and distributions (A) in connection
         with the liquidation, dissolution or winding up of the Company or (B)
         paid exclusively in cash and (3) any capital stock, evidences of
         indebtedness, cash or assets distributed upon a merger or
         consolidation to which Section 10.07 applies) (the foregoing
         hereinafter in this Section 10.06(d) called the "SUBJECT SECURITIES"),
         unless the Company elects to reserve such Subject Securities for
         distribution to the Holders upon conversion of the Securities so that
         any such Holder converting Securities will receive upon such
         conversion, in addition to the shares of Common Stock to which such
         Holder is entitled, the amount and kind of such Subject Securities
         which such Holder would have received if such Holder had converted its
         Securities into Common Stock immediately prior to the Record Date for
         such distribution of the Subject Securities, then, in each such case,
         the Conversion Price shall be reduced so that the same shall be equal
         to the price determined by multiplying the Conversion Price in effect
         immediately prior to the close of business on the Record Date with
         respect to such distribution by a fraction of which the numerator
         shall be the Current Market Price on such date less the fair market
         value on such date of the portion of the Subject Securities so
         distributed applicable to one share of Common Stock and the
         denominator shall be such Current Market Price, such reduction to
         become effective immediately prior to the opening of business on the
         day following the Record Date; PROVIDED, HOWEVER, that in the event
         the then fair market value of the portion of the Subject Securities so
         distributed applicable to one share of Common Stock is equal to or
         greater than the Current Market Price on the Record Date, then in lieu
         of the foregoing adjustment, adequate provision shall be made so that
         each Holder shall have the right to receive upon conversion of a
         Security (or any portion thereof) the amount of Subject Securities
         such Holder would have received had such Holder converted such
         Security (or portion thereof) immediately prior to such Record Date.
         In the event that such dividend or distribution is not so paid or
         made, the Conversion Price shall again be adjusted to be the
         Conversion Price which would then be in effect if such dividend or
         distribution had not been declared.

                  For purposes of this Section 10.06(d), rights or warrants
         distributed by the Company to all holders of Common Stock entitling the
         holders thereof to subscribe for or purchase shares of the Company's
         capital stock (either initially or under certain circumstances) that
         are (i) deemed to be transferred with such shares of Common Stock; (ii)
         not exercisable; and (iii) issued in respect of future issuances of
         Common Stock, until the occurrence of a specified event or events
         ("TRIGGER EVENT") shall be deemed not to have been distributed and no
         adjustment to the Conversion Price with respect thereto shall be made
         until the occurrence of the earliest Trigger Event. If any such right
         or warrant is subject to subsequent events, upon the occurrence of
         which such right or warrant shall become exercisable to purchase
         different securities, evidences of indebtedness or other assets or
         entitle the holder to purchase a different number or amount of the
         foregoing or to purchase any of the foregoing at a different purchase
         price, then the occurrence of each such event shall be deemed to be the
         date of issuance and record date with respect to a new right or warrant
         (and a termination or expiration of the existing right or warrant
         without exercise by the holder thereof). In addition, in the event of
         any distribution (or deemed distribution) of rights or warrants, or any
         Trigger Event or other event (of the type described in the preceding
         sentence) with respect thereto, that resulted in an adjustment to the
         Conversion Price under this Section 10.06(d), (1) in the case of any
         such rights or warrants which shall all have been redeemed or
         repurchased without exercise by any

<PAGE>
                                       -43-

         holders thereof, the Conversion Price shall be readjusted upon such
         final redemption or repurchase to give effect to such distribution or
         Trigger Event, as the case may be, as though it were a cash
         distribution, equal to the per share redemption or repurchase price
         received by a holder of Common Stock with respect to such rights or
         warrants (assuming such holder had retained such rights or warrants),
         made to all holders of Common Stock as of the date of such redemption
         or repurchase, and (2) in the case of such rights or warrants all of
         which shall have expired or been terminated without exercise, the
         Conversion Price shall be readjusted as if such rights and warrants
         had never been issued.

                  For purposes of this Section 10.06(d) and Sections 10.06(a)
         and (b), any dividend or distribution to which this Section 10.06(d) is
         otherwise applicable that also includes shares of Common Stock, or
         rights or warrants to subscribe for or purchase shares of Common Stock
         applies (or both), shall be deemed instead to be (1) a dividend or
         distribution of the evidences of indebtedness, assets, shares of
         capital stock, rights or warrants (other than such shares of Common
         Stock or rights or warrants) (and any Conversion Price reduction
         required by this Section 10.06(d) with respect to such dividend or
         distribution shall then be made) immediately followed by (2) a dividend
         or distribution of such shares of Common Stock or such rights or
         warrants (and any further Conversion Price reduction required by
         Sections 10.06(a) and (b) with respect to such dividend or distribution
         shall then be made), except (A) the Record Date of such dividend or
         distribution shall be substituted as "the date fixed for the
         determination of stockholders entitled to receive such dividend or
         other distribution", "Record Date fixed for such determination" and
         "Record Date" within the meaning of Section 10.06(a) and as "the date
         fixed for the determination of stockholders entitled to receive such
         rights or warrants", "the Record Date fixed for the determination of
         the stockholders entitled to receive such rights or warrants" and "such
         Record Date" within the meaning of Section 10.06(b) and (B) any shares
         of Common Stock included in such dividend or distribution shall not be
         deemed "outstanding at the close of business on the Record Date fixed
         for such determination" within the meaning of Section 10.06(a).

                  With respect to any stockholder rights plan existing on the
         date hereof or in the event that the Company implements any other
         stockholder rights plan, upon conversion of the Securities the Holders
         will receive, in addition to the Common Stock issuable upon such
         conversion, the rights issued under such rights plan (notwithstanding
         the occurrence of an event causing such rights to separate from the
         Common Stock at or prior to the time of conversion); PROVIDED, a Holder
         who is a holder of Common Stock (or direct or indirect interests
         therein) at the time of conversion, but who is not entitled as such a
         holder to such rights pursuant to the terms of any such plan, shall not
         be eligible to receive any such rights hereunder. Any distribution of
         rights or warrants pursuant to a stockholder rights plan complying with
         the requirements set forth in the immediately preceding sentence of
         this paragraph shall not constitute a distribution of rights or
         warrants for the purposes of the other provisions of this Section
         10.06(d) and no adjustment of the Conversion Price shall be made.

                  (e) In case the Company shall, by dividend or otherwise,
         distribute to all holders of its Common Stock cash (excluding any cash
         that is distributed upon a merger or consolidation to which Section
         10.07 applies or as part of a distribution referred to in Section
         10.06(d)), in

<PAGE>
                                       -44-

         an aggregate amount that, combined together with (1) the aggregate
         amount of all other such all-cash distributions to all holders of its
         Common Stock within the twelve (12) months preceding the date of
         payment of such distribution, and in respect of which no adjustment
         pursuant to this Section 10.06(e) has been made, and (2) the aggregate
         of any cash plus the fair market value of consideration payable in
         respect of any tender offer by the Company or any subsidiary for all
         or any portion of the Common Stock concluded within the twelve (12)
         months preceding the date of payment of such distribution, and in
         respect of which no adjustment pursuant to Section 10.06(f) has been
         made (such aggregate amount, the "COMMON DIVIDEND AMOUNT"), exceeds
         10% of the product of the Current Market Price on the Record Date with
         respect to such distribution times the number of shares of Common
         Stock outstanding on such date (the "MARKET CAPITALIZATION"), then,
         and in each such case, immediately after the close of business on such
         date, the Conversion Price shall be reduced so that the same shall
         equal the price determined by multiplying the Conversion Price in
         effect immediately prior to the close of business on such Record Date
         by a fraction (i) the numerator of which shall be equal to the Current
         Market Price on the Record Date less an amount equal to the quotient
         of (x) the amount by which the Common Dividend Amount exceeds 10% of
         the Market Capitalization and (y) the number of shares of Common Stock
         outstanding on the Record Date and (ii) the denominator of which shall
         be equal to the Current Market Price on such date; PROVIDED, HOWEVER,
         that in the event the portion of the cash so distributed applicable to
         one share of Common Stock is equal to or greater than the Current
         Market Price of the Common Stock on the Record Date, in lieu of the
         foregoing adjustment, adequate provision shall be made so that each
         Holder shall have the right to receive upon conversion of a Security
         (or any portion thereof) the amount of cash such Holder would have
         received had such holder converted such Security (or portion thereof)
         immediately prior to such Record Date. In the event that such dividend
         or distribution is not so paid or made, the Conversion Price shall
         again be adjusted to be the Conversion Price which would then be in
         effect if such dividend or distribution had not been declared.

                  (f) In case a tender offer made by the Company or any
         subsidiary for all or any portion of the Common Stock shall expire and
         such tender offer shall require the payment to holders of Common Stock
         of an aggregate consideration that together with

                           (1) the aggregate of the cash plus the fair market
                  value of consideration payable in respect of any other tender
                  offers by the Company or any of its subsidiaries for all or
                  any portion of the Common Stock expiring within the twelve
                  (12) months preceding the expiration of such tender offer and
                  in respect of which no adjustment pursuant to this Section
                  10.06(f) has been made, and

                           (2) the aggregate amount of any all-cash
                  distributions to all holders of the Company's Common Stock
                  made within twelve (12) months preceding the expiration of
                  such tender offer and in respect of which no adjustment
                  pursuant to Section 10.06(e) has been made,

         exceeds 10% of the product of the Current Market Price as of the time
         of expiration of such tender offer times the number of shares of Common
         Stock outstanding at such time, then, and

<PAGE>
                                       -45-

         in each such case, immediately prior to the opening of business on the
         day after the expiration of such tender offer, the Conversion Price
         shall be adjusted so that the same shall equal the price determined by
         multiplying the Conversion Price in effect immediately prior to the
         close of business on the date of the expiration of such tender offer
         by a fraction of which the numerator shall be the number of shares of
         Common Stock outstanding on the date of expiration of the tender offer
         multiplied by the Current Market Price of the Common Stock on the
         Trading Day next succeeding the date of expiration of the tender offer
         and the denominator shall be the sum of (x) the fair market value of
         the aggregate consideration payable for all shares of Common Stock
         validly tendered and not withdrawn as of the date of expiration of the
         tender offer and (y) the product of the number of shares of Common
         Stock outstanding less all shares validly tendered and not withdrawn
         as of the date of expiration of the tender offer and the Current
         Market Price of the Common Stock on the Trading Day next succeeding
         the date of expiration of the tender offer, such reduction (if any) to
         become effective immediately prior to the opening of business on the
         day following the date of expiration of the tender offer. In the event
         the Company is permanently prevented by applicable law from effecting
         any such purchases or all such purchases are rescinded, the Conversion
         Price shall again be adjusted to be the Conversion Price which would
         then be in effect if such tender offer had not been made. If the
         application of this Section 10.06(f) to any tender offer would result
         in an increase in the Conversion Price, no adjustment shall be made
         for such tender offer under this Section 10.06(f).

                  (g) In case of a tender or exchange offer made by a Person
         other than the Company or any subsidiary for an amount which increases
         such Person's ownership of Common Stock to more than 25% of the Common
         Stock outstanding and involves the payment by such Person of
         consideration per share of Common Stock having a fair market value that
         exceeds the Current Market Price of the Common Stock on the Trading Day
         next succeeding the closing date of such offer, and, as of the closing
         date of such offer, the Board of Directors does not recommend rejection
         of such offer, then the Conversion Price shall be reduced so that the
         same shall equal the price determined by multiplying the Conversion
         Price in effect on the closing date of such offer by a fraction of
         which the numerator shall be the number of shares of Common Stock
         outstanding on the closing date of such offer multiplied by the Current
         Market Price of the Common Stock on the Trading Day next succeeding the
         closing date of such offer and the denominator shall be the sum of (x)
         the fair market value of the aggregate consideration payable for all
         shares validly tendered or exchanged and not withdrawn as of the
         closing date of such offer and (y) the product of the number of shares
         of Common Stock outstanding less all shares validly tendered and not
         withdrawn as of the closing date of such offer and the Current Market
         Price of the Common Stock on the Trading Day next succeeding the
         closing date of such offer, such reduction to become effective
         immediately prior to the opening of business on the day following the
         closing date of such offer. In the event such Person is permanently
         prevented by applicable law from effecting any such purchases or all
         such purchases are rescinded, the Conversion Price shall again be
         adjusted to be the Conversion Price which would then be in effect if
         such tender or exchange offer had not been made. Notwithstanding the
         foregoing, the adjustment described in this Section 10.06(g) shall not
         be made if, as of the closing date of such offer, the offering
         documents with respect to such offer

<PAGE>
                                       -46-

         disclose a plan or intention to cause the Company to engage in any
         transaction described in Article Five.

                  (h)  For purposes of this Section 10.06, the following terms
         have the meanings indicated:

                           (1) "CLOSING PRICE" with respect to any securities on
                  any day shall mean the closing sale price regular way on such
                  day or, in case no such sale takes place on such day, the
                  average of the reported closing bid and asked prices, regular
                  way, in each case on the Nasdaq National Market or New York
                  Stock Exchange, as applicable, or, if such security is not
                  listed or admitted to trading on such Nasdaq National Market
                  or New York Stock Exchange, on the principal national security
                  exchange or quotation system on which such security is quoted
                  or listed or admitted to trading, or, if not quoted or listed
                  or admitted to trading on any national securities exchange or
                  quotation system, the average of the closing bid and asked
                  prices of such security on the over-the-counter market on the
                  day in question as reported by the National Quotation Bureau
                  Incorporated, or a similar generally accepted reporting
                  service, or if not so available, in such manner as furnished
                  by any New York Stock Exchange member firm selected from time
                  to time by the Board of Directors for that purpose, or a price
                  determined in good faith by the Board of Directors, whose
                  determination shall be conclusive and described in a Board
                  Resolution.

                           (2) "CURRENT MARKET PRICE" shall mean the average of
                  the Closing Prices per share of Common Stock for the ten (10)
                  consecutive Trading Days immediately prior to the date for
                  which a Current Market Price is required; PROVIDED, HOWEVER,
                  that:

                                    (1) if the "ex" date (as hereinafter
                           defined) for any event (other than the issuance or
                           distribution requiring such computation) that
                           requires an adjustment to the Conversion Price
                           pursuant to Section 10.06(a), (b), (c), (d), (e), (f)
                           or (g) occurs during such ten consecutive Trading
                           Days, then the Closing Price for each Trading Day
                           prior to the "ex" date for such other event shall be
                           adjusted by multiplying such Closing Price by the
                           same fraction by which the Conversion Price is so
                           required to be adjusted as a result of such other
                           event,

                                    (2) if the "ex" date for any event (other
                           than the issuance or distribution requiring such
                           computation) that requires an adjustment to the
                           Conversion Price pursuant to Section 10.06(a), (b),
                           (c), (d), (e), (f) or (g) occurs on or after the "ex"
                           date for the issuance or distribution requiring such
                           computation and prior to the day in question, then
                           the Closing Price for each Trading Day on and after
                           the "ex" date for such other event shall be adjusted
                           by multiplying such Closing Price by the reciprocal
                           of the fraction by which the Conversion Price is so
                           required to be adjusted as a result of such other
                           event, and

<PAGE>
                                       -47-

                                    (3) if the "ex" date for the issuance or
                           distribution requiring such computation is prior to
                           the day in question, after taking into account any
                           adjustment required pursuant to clause (1) or (2) of
                           this proviso, the Closing Price for each Trading Day
                           on or after such "ex" date shall be adjusted by
                           adding thereto the amount of any cash and the fair
                           market value of the evidences of indebtedness, shares
                           of capital stock or assets being distributed
                           applicable to one share of Common Stock as of the
                           close of business on the day before such "ex" date.

                           For purposes of any computation under Sections
                  10.06(f) or (g), the Current Market Price of the Common Stock
                  on any date shall be deemed to be the average of the daily
                  Closing Prices per share of Common Stock for such day and the
                  next two succeeding Trading Days; PROVIDED, HOWEVER, that if
                  the "ex" date for any event (other than the tender offer
                  requiring such computation) that requires an adjustment to the
                  Conversion Price pursuant to Section 10.06(a), (b), (c), (d),
                  (e), (f) and (g) occurs on or after the date of expiration of
                  the tender or exchange offer requiring such computation and
                  prior to the day in question, the Closing Price for each
                  Trading Day on and after the "ex" date for such other event
                  shall be adjusted by multiplying such Closing Price by the
                  reciprocal of the fraction by which the Conversion Price is so
                  required to be adjusted as a result of such other event.

                           For purposes of this definition, the term "ex" date,
                  (1) when used with respect to any issuance or distribution,
                  means the first date on which the Common Stock trades regular
                  way on the relevant exchange or in the relevant market from
                  which the Closing Price was obtained without the right to
                  receive such issuance or distribution, (2) when used with
                  respect to any subdivision or combination of shares of Common
                  Stock, means the first date on which the Common Stock trades
                  regular way on such exchange or in such market after the time
                  at which such subdivision or combination becomes effective,
                  and (3) when used with respect to any tender or exchange offer
                  means the first date on which the Common Stock trades regular
                  way on such exchange or in such market after the Expiration
                  Time of such offer.

                           (3) "FAIR MARKET VALUE" shall mean the amount which a
                  willing buyer would pay a willing seller in an arm's length
                  transaction determined in good faith by the Board of
                  Directors, whose determination shall be conclusive and
                  described in a Board Resolution.

                           (4) "RECORD DATE" shall mean, with respect to any
                  dividend, distribution or other transaction or event in which
                  the holders of Common Stock have the right to receive any
                  cash, securities or other property or in which the Common
                  Stock (or other applicable security) is exchanged for or
                  converted into any combination of cash, securities or other
                  property, the date fixed for determination of stockholders
                  entitled to receive such cash, securities or other property
                  (whether such date is fixed by the Board of Directors or by
                  statute, contract or otherwise).

<PAGE>
                                       -48-

                           (5) "TRADING DAY" shall mean (x) if the applicable
                  security is listed or admitted for trading on the New York
                  Stock Exchange or another national security exchange, a day on
                  which the New York Stock Exchange or such other national
                  security exchange, as the case may be, is open for business,
                  (y) if the applicable security is quoted on the Nasdaq
                  National Market, a day on which trades may be made thereon or
                  (z) if the applicable security is not so listed, admitted for
                  trading or quoted, any day other than a Saturday or Sunday or
                  a day on which banking institutions in the State of New York
                  are authorized or obligated by law or executive order to
                  close.

                  (i) The Company may make such reductions in the Conversion
         Price, in addition to those required by Sections 10.06(a), (b), (c),
         (d), (e), (f) and (g), as the Board of Directors considers to be
         advisable to avoid or diminish any income tax to holders of Common
         Stock or rights to purchase Common Stock resulting from any dividend or
         distribution of stock (or rights to acquire stock) or from any event
         treated as such for income tax purposes.

                  To the extent permitted by applicable law, the Company from
         time to time may reduce the Conversion Price by any amount for any
         period of time if the period is at least twenty (20) days and the
         reduction is irrevocable during the period. Whenever the Conversion
         Price is reduced pursuant to the preceding sentence, the Company shall
         mail to the Holder of each Security at his last address appearing on
         the register maintained by the Registrar a notice of the reduction at
         least fifteen (15) days prior to the date the reduced Conversion Price
         takes effect, and such notice shall state the reduced Conversion Price
         and the period during which it will be in effect.

                  (j) No adjustment in the Conversion Price shall be required
         unless such adjustment would require an increase or decrease of at
         least 1% in such price; HOWEVER, any adjustment that would otherwise be
         required to be made shall be carried forward and taken into account in
         any subsequent adjustment. All calculations under this Article Ten
         shall be made by the Company and shall be made to the nearest cent or
         to the nearest one hundredth of a share, as the case may be. No
         adjustment need be made for a change in the par value or no par value
         of the Common Stock.

                  (k) Whenever the Conversion Price is adjusted as herein
         provided, the Company shall promptly file with the Trustee, and any
         Conversion Agent other than the Trustee, an Officers' Certificate
         setting forth the Conversion Price after such adjustment and setting
         forth a brief statement of the facts requiring such adjustment. Unless
         and until a Trust Officer of the Trustee shall have received such
         Officers' Certificate, the Trustee shall not be deemed to have
         knowledge of any adjustment of the Conversion Price and may assume
         without inquiry that the last Conversion Price of which it has
         knowledge remains in effect. Promptly after delivery of such
         certificate, the Company shall prepare a notice of such adjustment of
         the Conversion Price setting forth the adjusted Conversion Price and
         the date on which each adjustment becomes effective and shall mail such
         notice of such adjustment of the Conversion Price to the Holder of each
         Security at his last address appearing on the register maintained by
         the Registrar, within twenty (20) days of the effective date of such
         adjustment. Failure to deliver such notice shall not affect the
         legality or validity of any such adjustment.

<PAGE>
                                       -49-

                  (l) In any case in which this Section 10.06 provides that an
         adjustment shall become effective immediately after a Record Date for
         an event, the Company may defer until the occurrence of such event (i)
         issuing to the Holder of any Security converted after such Record Date
         and before the occurrence of such event the additional shares of Common
         Stock issuable upon such conversion by reason of the adjustment
         required by such event over and above the Common Stock issuable upon
         such conversion before giving effect to such adjustment and (ii) paying
         to such Holder any amount in cash in lieu of any fraction pursuant to
         Section 10.03.

                  (m) For purposes of this Section 10.06, the number of shares
         of Common Stock at any time outstanding shall not include shares held
         in the treasury of the Company but shall include shares issuable in
         respect of scrip certificates issued in lieu of fractions of shares of
         Common Stock. The Company will not pay any dividend or make any
         distribution on shares of Common Stock held in the treasury of the
         Company.

SECTION 10.07.        EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR SALE

                  In the case of (i) any reclassification or change of the
outstanding shares of Common Stock (other than a change in par value, or from
par value to no par value, or from no par value to par value, or as a result of
a subdivision or combination), (ii) any consolidation, merger or combination of
the Company with another corporation as a result of which holders of Common
Stock shall be entitled to receive stock, securities or other property or assets
(including cash) with respect to or in exchange for such Common Stock, or (iii)
any sale or conveyance of the properties and assets of the Company as, or
substantially as, an entirety to any other corporation as a result of which
holders of Common Stock shall be entitled to receive stock, securities or other
property or assets (including cash) with respect to or in exchange for such
Common Stock, then, unless an adjustment with respect thereto shall be made
pursuant to Section 10.06, the Company or the successor or purchasing
corporation, as the case may be, shall execute with the Trustee a supplemental
indenture providing that the Securities shall be convertible into the kind and
amount of shares of stock and other securities or property or assets (including
cash) receivable upon such reclassification, change, consolidation, merger,
combination, sale or conveyance by a holder of a number of shares of Common
Stock issuable upon conversion of such Securities immediately prior to such
reclassification, change, consolidation, merger, combination, sale or conveyance
assuming such holder of Common Stock did not exercise rights of election, if
any, as to the kind or amount of securities, cash or other property receivable
upon such consolidation, merger, statutory exchange, sale or conveyance. Such
supplemental indenture shall provide for adjustments which shall be as nearly
equivalent as may be practicable to the adjustments provided for in this Article
Ten. If, in the case of any such reclassification, change, consolidation,
merger, combination, sale or conveyance, the stock or other securities and
assets receivable thereupon by a holder of shares of Common Stock include shares
of stock or other securities and assets of a Person other than the successor or
purchasing corporation, as the case may be, in such reclassification, change,
consolidation, merger, combination, sale or conveyance, then such supplemental
indenture shall also be executed by such other Person and shall contain such
additional provisions to protect the interests of the Holders as the Board of
Directors shall reasonably consider necessary by reason of the foregoing.

<PAGE>
                                       -50-

                  The Company shall cause notice of the execution of such
supplemental indenture to be mailed to each Holder of Securities, at its address
appearing on the register maintained by the Registrar, within twenty (20) days
after execution thereof. Failure to deliver such notice shall not affect the
legality or validity of such supplemental indenture.

SECTION 10.08.        NOTICE OF CERTAIN TRANSACTIONS.

                  If:

                  (1)      the Company proposes to take any action that would
         require an adjustment in the conversion rate;

                  (2)      the Company proposes to take any action that would
         require a supplemental indenture pursuant to Section 10.07; or

                  (3)      there is a proposed liquidation, winding up or
         dissolution of the Company,

the Company shall mail to Holders a notice stating the proposed record date for
a dividend or distribution or the proposed effective date of a subdivision,
combination, reclassification, consolidation, merger, transfer, lease,
liquidation or dissolution. The Company shall mail the notice at least 10 days
before such date. Failure to mail the notice or any defect in it shall not
affect the validity of the transaction.

SECTION 10.09.        COMPANY DETERMINATION FINAL.

                  Any determination that the Board of Directors makes pursuant
to this Article is conclusive, absent manifest error.

SECTION 10.10.        TRUSTEE'S DISCLAIMER.

                  The Trustee has no duty to determine when an adjustment under
this Article or under the terms of the Securities should be made, how it should
be made or what it should be. Such information shall be timely provided to the
Trustee in an Officers' Certificate. The Trustee has no duty to determine
whether any provisions of a supplemental indenture under Section 10.07 are
correct. The Trustee makes no representation as to the validity or value of any
securities or assets issued upon conversion of Securities. The Trustee shall not
be responsible for the Company's failure to comply with this Article. Each
Conversion Agent other than the Company shall have the same protection under
this Section 10.10 as the Trustee.

                                 ARTICLE ELEVEN

                                   [RESERVED]

<PAGE>
                                       -51-

                                 ARTICLE TWELVE

                                  SUBORDINATION

SECTION 12.01.        SECURITIES SUBORDINATED TO SENIOR INDEBTEDNESS.

                  The Company covenants and agrees, and each Holder of a
Security, by his acceptance thereof, likewise covenants and agrees, that the
indebtedness represented by the Securities and the payment of the principal of
(and premium, if any) and interest on each and all of the Securities is hereby
expressly subordinate and junior, to the extent and in the manner hereinafter
set forth, in right of payment to the prior payment in full of all Senior
Indebtedness.

                  (a) Upon any distribution of assets of the Company, upon any
dissolution, winding up, liquidation or reorganization of the Company, whether
in bankruptcy, insolvency, reorganization or receivership proceedings or upon an
assignment for the benefit of creditors or any other marshaling of the assets
and liabilities of the Company or otherwise, then the holders of all Senior
Indebtedness shall first be entitled to receive payment of the full amount due
thereon in cash or other consideration satisfactory to the holders of Senior
Indebtedness in respect of principal (and premium, if any) and interest, or
provision shall be made for such amount in cash or other consideration
satisfactory to the holders of Senior Indebtedness, before the Holders of any of
the Securities are entitled to receive any payment or distribution of any
character, whether in cash, securities or other property, on account of the
principal of (or premium, if any) or interest on the indebtedness evidenced by
the Securities.

                  For purposes of this Article Twelve, the words, "cash,
securities or other property" shall not be deemed to include shares of stock of
the Company as reorganized or readjusted, or securities of the Company or any
other corporation provided for by a plan of reorganization or readjustment, the
payment of which is subordinated at least to the extent provided in this Article
Twelve with respect to the Securities to the payment of all Senior Indebtedness
which may at the time be outstanding; PROVIDED that (i) the Senior Indebtedness
is assumed by the new corporation, if any, resulting from any reorganization or
readjustment, and (ii) the rights of the holders of Senior Indebtedness (other
than leases which are not assumed by the Company or the new corporation, as the
case may be) are not, without the consent of such holders, altered by such
reorganization or readjustment. The consolidation of the Company with, or the
merger of the Company into, another Person or the liquidation or dissolution of
the Company following the conveyance or transfer of its property as an entirety,
or substantially as an entirety, to another Person upon the terms and conditions
provided for in Article Five shall not be deemed a dissolution, winding-up,
liquidation or reorganization for the purposes of this Section 12.01(a) if such
other Person shall, as a part of such consolidation, merger, conveyance or
transfer, comply with the conditions stated in Article Five.

                  (b) No payment shall be made by the Company with respect to
the principal of, premium, if any, or interest on the Securities or to acquire
any of the Securities, if (i) any default in payment of the principal of or
premium, if any, or interest on, rent under, or any other payment obligation
under any Senior Indebtedness occurs and is continuing (a "PAYMENT DEFAULT")
beyond any applicable grace period with respect thereto, unless and until all
such payments due in respect of such Senior

<PAGE>
                                       -52-

Indebtedness have been paid in full in cash or other consideration satisfactory
to holders of Senior Indebtedness or such default shall have been cured or
waived or shall have ceased to exist, (ii) any event of default, other than a
Payment Default, with respect to any Designated Senior Indebtedness occurs and
is continuing permitting the holders of such Designated Senior Indebtedness (or
a trustee or other representative on behalf of the holders thereof) to declare
such Designated Senior Indebtedness due and payable prior to the date on which
it would otherwise have become due and payable, and the Trustee receives notice
thereof from the Company or by any holders of such Designated Senior
Indebtedness (or a trustee or other representative on behalf of the holders
thereof) (the "PAYMENT BLOCKAGE NOTICE"), for a period (the "PAYMENT BLOCKAGE
PERIOD") ending on the earlier of the date on which such event of default shall
have been cured or waived or shall have ceased to exist or 179 days after
receipt of the Payment Blockage Notice, or (iii) any judicial proceeding shall
be pending with respect to any such default in payment or event of default;
PROVIDED, FURTHER, any number of additional Payment Blockage Periods may be
commenced during an existing Payment Blockage Period; PROVIDED, HOWEVER, that no
such additional Payment Blockage Period shall extend beyond the initial Payment
Blockage Period. Notwithstanding anything in the subordination provisions of
this Indenture or the Securities to the contrary, (x) in no event will a Payment
Blockage Period extend beyond 179 days from the date of the Payment Blockage
Notice in respect thereof was given and (y) there shall be a period of at least
181 consecutive days in each 360-day period when no Payment Blockage Period is
in effect. No nonpayment default that existed or was continuing on the date of
delivery of any Payment Blockage Notice to the Trustee shall be the basis for a
subsequent payment blockage notice.

                  (c) If the maturity of the Securities is accelerated, no
payment may be made on the Securities until all amounts due or to become due on
Senior Indebtedness have been paid in full in cash or other consideration
satisfactory to holders of Senior Indebtedness or until such acceleration has
been cured or waived.

                  (d) In the event that, notwithstanding the foregoing
provisions of Sections 12.01(a), (b) and (c), any payment on account of
principal of or interest on the Securities shall be made by or on behalf of the
Company and received by the Trustee, by any Holder or by any Paying Agent (or,
if the Company is acting as its own Paying Agent, money for any such payment
shall be segregated and held in trust), at a time when such payment is not
permitted by any of such provisions, then, unless and until all Senior
Indebtedness (or Designated Senior Indebtedness, in the case of Section
12.01(b)) is paid in full in cash or other consideration satisfactory to the
holders thereof, or such payment is otherwise permitted to be made by the
provisions of each of Sections 12.01(a), 12.01(b) and 12.01(c) (subject, in each
case, to the provisions of Section 12.07), such payment on account of principal
of or interest on the Securities shall be held in trust for the benefit of, and
shall be immediately paid over to, the holders of Senior Indebtedness (or
Designated Senior Indebtedness, in the case of Section 12.01(b)) or their
representative or representatives or the trustee or trustees under any indenture
under which any instruments evidencing any of the Senior Indebtedness (or
Designated Senior Indebtedness, in the case of Section 12.01(b)) may have been
issued, as their interests may appear.

                  Regardless of anything to the contrary herein, nothing shall
prevent (A) any payment by the Company or the Trustee to Holders of amounts in
connection with a redemption of Securities if (i) notice of such redemption has
been given pursuant to Section 3.01 prior to the receipt by the Trus-

<PAGE>
                                       -53-

tee of a Payment Blockage Notice, and (ii) such notice of redemption is given
not earlier than 75 days before the Redemption Date, or (B) any payment by the
Trustee to the Holders of amounts deposited with it pursuant to Section 8.01.

SECTION 12.02.        SUBROGATION.

                  Subject to the payment in full of all Senior Indebtedness to
which the indebtedness evidenced by the Securities is in the circumstances
subordinated as provided in Section 12.01, the Holders of the Securities
(together with the holders of any other indebtedness of the Company which is
subordinate in right of payment to the payment in full of all Senior
Indebtedness, which is not subordinate in right of payment to the Securities and
which by its terms grants such right of subrogation to the holders thereof)
shall be subrogated to the rights of the holders of such Senior Indebtedness to
receive payments or distributions of cash, property or securities of the Company
applicable to such Senior Indebtedness until all amounts owing on the Securities
shall be paid in full, and, as between the Company, its creditors other than
holders of such Senior Indebtedness, and the Holders of the Securities, no such
payment or distribution made to the holders of Senior Indebtedness by virtue of
this Article which otherwise would have been made to the Holders of the
Securities shall be deemed to be a payment by the Company on account of such
Senior Indebtedness, it being understood that the provisions of this Article are
and are intended solely for the purpose of defining the relative rights of the
Holders of the Securities, on the one hand, and the holders of Senior
Indebtedness, on the other hand.

SECTION 12.03.        OBLIGATION OF COMPANY UNCONDITIONAL.

                  Nothing contained in this Article or elsewhere in this
Indenture or in the Securities is intended to or shall impair, as between the
Company, its creditors other than the holders of Senior Indebtedness, and the
Holders of the Securities, the obligation of the Company, which is absolute and
unconditional, to pay to the Holders of the Securities the principal of (and
premium, if any) and interest on the Securities as and when the same shall
become due and payable in accordance with their terms, or is intended to or
shall affect the relative rights of the Holders of the Securities and creditors
of the Company other than the holders of Senior Indebtedness, nor shall anything
herein or therein prevent the Trustee or the Holder of any Security from
exercising all remedies otherwise permitted by applicable law upon default under
this Indenture, subject to the rights, if any, under this Article of the holders
of Senior Indebtedness in respect of cash, property or securities of the Company
received upon the exercise of any such remedy.

SECTION 12.04.        MODIFICATION OF TERMS OF SENIOR INDEBTEDNESS.

                  Any renewal or extension of the time of payment of any Senior
Indebtedness or the exercise by the holders of Senior Indebtedness of any of
their rights under any instrument creating or evidencing Senior Indebtedness,
including without limitation the waiver of default thereunder, may be made or
done all without notice to or assent from the Holders of the Securities or the
Trustee.

                  No compromise, alteration, amendment, modification, extension,
renewal or other change of, or waiver, consent or other action in respect of,
any liability or obligation under or in respect of, or of any of the terms,
covenants or conditions of any indenture or other instrument under

<PAGE>
                                       -54-

which any Senior Indebtedness is outstanding or of such Senior Indebtedness,
whether or not such release is in accordance with the provisions of any
applicable document, shall in any way alter or affect any of the provisions of
this Article or of the Securities relating to the subordination thereof.

SECTION 12.05.        [RESERVED]

SECTION 12.06.        EFFECTUATION OF SUBORDINATION BY TRUSTEE.

                  Each Holder of Securities, by his acceptance thereof,
authorizes and directs the Trustee in his or her behalf to take such action as
may be necessary or appropriate to effectuate the subordination provided in this
Article and appoints the Trustee his or attorney-in-fact for any and all such
purposes.

                  Upon any payment or distribution of assets of the Company
referred to in this Article, the Trustee and the Holders of the Securities shall
be entitled to rely upon any order or decree made by any court of competent
jurisdiction in which any such dissolution, winding up, liquidation or
reorganization proceeding affecting the affairs of the Company is pending or
upon a certificate of the trustee in bankruptcy, receiver, assignee for the
benefit of creditors, liquidating trustee or agent or other Person making any
payment or distribution, delivered to the Trustee or to the Holders of the
Securities, for the purpose of ascertaining the Persons entitled to participate
in such payment or distribution, and as to other facts pertinent to the right of
such Persons under this Article, and if such evidence is not furnished, the
Trustee may defer any payment to such Persons pending judicial determination as
to the right of such Persons to receive such payment.

SECTION 12.07.        KNOWLEDGE OF TRUSTEE.

                  Notwithstanding the provisions of this Article or any other
provisions of this Indenture, the Trustee shall not be charged with knowledge of
the existence of any Senior Indebtedness, of any default in payment of
principal, premium (if any) or interest on any Senior Indebtedness, or of any
facts which would prohibit the making of any payment of moneys to or by the
Trustee, or the taking of any other action by the Trustee, unless and until a
Trust Officer of the Trustee having responsibility for the administration of the
trust established by this Indenture shall have received written notice thereof
from the Company, any Holder of Securities, any Paying or Conversion Agent of
the Company or the holder or representative of any class of Senior Indebtedness,
and, prior to the receipt of any such written notice, the Trustee shall be
entitled in all respects to assume that no such default or facts exist;
PROVIDED, HOWEVER, that unless on a date one (1) Business Day prior to the date
upon which by the terms hereof any such moneys may become payable for any
purpose the Trustee shall have received the notice provided for in this Section
12.07, then, anything herein contained to the contrary notwithstanding, the
Trustee shall have full power and authority to receive such moneys and apply the
same to the purpose for which they were received, and shall not be affected by
any notice to the contrary which may be received by it on or after such date.

<PAGE>
                                       -55-

SECTION 12.08.        TRUSTEE'S RELATION TO SENIOR INDEBTEDNESS.

                  The Trustee shall be entitled to all the rights set forth in
this Article with respect to any Senior Indebtedness at the time held by it, to
the same extent as any other holder of Senior Indebtedness and nothing in this
Indenture shall deprive the Trustee of any of its rights as such holder.

                  Nothing in this Article shall apply to claims of or payments
to the Trustee under or pursuant to Section 7.07.

                  With respect to the holders of Senior Indebtedness, the
Trustee undertakes to perform or to observe only such of its covenants and
obligations as are specifically set forth in this Article, and no implied
covenants or obligations with respect to the holders of Senior Indebtedness
shall be read into this Indenture against the Trustee. The Trustee shall not be
deemed to owe any fiduciary duty to the holders of Senior Indebtedness and the
Trustee shall not be liable to any holder of Senior Indebtedness if it shall pay
over or deliver to Holders, the Company or any other Person moneys or assets to
which any holder of Senior Indebtedness shall be entitled by virtue of this
Article or otherwise.

SECTION 12.09.        RIGHTS OF HOLDERS OF SENIOR INDEBTEDNESS NOT IMPAIRED.

                  No right of any present or future holder of any Senior
Indebtedness to enforce the subordination herein shall at any time or in any way
be prejudiced or impaired by any act or failure to act on the part of the
Company or by any noncompliance by the Company with the terms, provisions and
covenants of this Indenture, regardless of any knowledge thereof any such holder
may have or be otherwise charged with.

SECTION 12.10.        CERTAIN CONVERSIONS NOT DEEMED PAYMENT.

                  For the purposes of Article Ten only, (1) the issuance and
delivery of junior securities upon conversion of Securities in accordance with
Article Ten shall not be deemed to constitute a payment or distribution on
account of the principal of, premium, if any, or interest on Securities or on
account of the purchase or other acquisition of Securities, and (2) the payment,
issuance or delivery of cash (except in satisfaction of fractional shares
pursuant to Section 10.03), property or securities (other than junior
securities) upon conversion of a Security shall be deemed to constitute payment
on account of the principal of, premium, if any, or interest on such Security.
For the purposes of this Section 12.10, the term "junior securities" means (a)
shares of any stock of any class of the Company or (b) securities of the Company
that are subordinated in right of payment to all Senior Indebtedness to
substantially the same extent as, or to a greater extent than, the Securities
are so subordinated as provided in this Article. Nothing contained in this
Article Twelve or elsewhere in this Indenture or in the Securities is intended
to or shall impair, as among the Company, its creditors (other than holders of
Senior Indebtedness) and the Holders, the right, which is absolute and
unconditional, of the Holder of any Security to convert such note in accordance
with Article Ten.

<PAGE>
                                       -56-

                                ARTICLE THIRTEEN

                                  MISCELLANEOUS

SECTION 13.01.        TRUST INDENTURE ACT CONTROLS.

                  If any provision of this Indenture limits, qualifies or
conflicts with another provision which is required to be included in this
Indenture by the TIA, the required provision shall control.

SECTION 13.02.        NOTICES.

                  Any notice or communication by the Company or the Trustee to
the other is duly given if in writing and delivered in person, mailed by
first-class mail or by express delivery to the other's address stated in this
Section 13.02. The Company or the Trustee by notice to the other may designate
additional or different addresses for subsequent notices or communications.

                  Any notice or communication to a Holder shall be mailed by
first-class mail to its address shown on the register kept by the Registrar.
Failure to mail a notice or communication to a Holder or any defect in it shall
not affect its sufficiency with respect to other Holders.

                  If a notice or communication is mailed in the manner provided
above, it is duly given, whether or not the addressee receives it.

                  If the Company mails a notice or communication to Holders, it
shall mail a copy to the Trustee and each Agent at the same time.

                  All notices or communications shall be in writing.

                  The Company's address is:

                           Gilead Sciences, Inc.
                           333 Lakeside Drive
                           Foster City, California 94404

                           Attention:  Gregg Alton, Esq., General Counsel

                  The Trustee's address is:

                           Chase Manhattan Bank and Trust Company,
                                National Association
                           101 California Street, Suite 2725
                           San Francisco, California 94111

                           Attention:  Rose Maravilla

<PAGE>
                                       -57-

                  The Trustee's address for purposes of Section 4.02 is:

                           Chase Manhattan Bank and Trust Company,
                                National Association
                           c/o The Chase Manhattan Bank
                           55 Water Street, North Building
                           New York, New York  10041

SECTION 13.03.        COMMUNICATION BY HOLDERS WITH OTHER HOLDERS.

                  Holders may communicate pursuant to TIA Section 312(b) with
other Holders with respect to their rights under this Indenture or the
Securities. The Company, the Trustee, the Registrar and anyone else shall
have the protection of TIA Section 312(c).

SECTION 13.04.        CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.

                  Upon any request or application by the Company to the Trustee
to take any action under this Indenture the Company shall furnish to the
Trustee:

                  (1) an Officers' Certificate stating that, in the opinion of
         the signers, all conditions precedent, if any, provided for in this
         Indenture relating to the proposed action have been complied with; and

                  (2) an Opinion of Counsel stating that, in the opinion of such
         counsel, all such conditions precedent have been complied with.

                  Each signer of an Officers' Certificate or an Opinion of
Counsel may (if so stated) rely, effectively, upon an Opinion of Counsel as to
legal matters and an Officers' Certificate as to factual matters if such signer
reasonably and in good faith believes in the accuracy of the document relied
upon.

SECTION 13.05.        STATEMENTS REQUIRED IN CERTIFICATE OR OPINION.

                  Each Officers' Certificate or Opinion of Counsel with respect
to compliance with a condition or covenant provided for in this Indenture shall
include:

                  (1)      a statement that the Person making such certificate
         or opinion has read such covenant or condition;

                  (2)      a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

<PAGE>
                                       -58-

                  (3)      a statement that, in the opinion of such Person, he
         or she has made such examination or investigation as is necessary to
         enable him or her to express an informed opinion as to whether or not
         such covenant or condition has been complied with; and

                  (4)      a statement as to whether or not, in the opinion of
         such Person, such condition or covenant has been complied with.

SECTION 13.06.        RULES BY TRUSTEE AND AGENTS.

                  The Trustee may make reasonable rules for action by or at a
meeting of Holders. The Registrar, Paying Agent or Conversion Agent may make
reasonable rules and set reasonable requirements for their respective functions.

SECTION 13.07.        LEGAL HOLIDAYS.

                  A "Legal Holiday" is a Saturday, a Sunday or a day on which
banking institutions are not required to be open in The City of New York, in the
State of New York or in the city in which the Trustee administers its corporate
trust business. If a payment date is a Legal Holiday at a place of payment,
payment may be made at that place on the next succeeding day that is not a Legal
Holiday, and no interest shall accrue on that payment for the intervening
period.

                  A "Business Day" is a day other than a Legal Holiday.

SECTION 13.08.        NO RECOURSE AGAINST OTHERS.

                  All liability described in the Securities of any director,
officer, employee or stockholder, as such, of the Company is waived and
released.

SECTION 13.09.        DUPLICATE ORIGINALS.

                  The parties may sign any number of copies of this Indenture.
Each signed copy shall be an original, but all of them together represent the
same agreement.

SECTION 13.10.        GOVERNING LAW.

                  The laws of the State of New York, without regard to
principles of conflicts of law, shall govern this Indenture and the Securities.

SECTION 13.11.        NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS.

                  This Indenture may not be used to interpret another indenture,
loan or debt agreement of the Company or a subsidiary. Any such indenture, loan
or debt agreement may not be used to interpret this Indenture.

<PAGE>
                                       -59-

SECTION 13.12.        SUCCESSORS.

                  All agreements of the Company in this Indenture and the
Securities shall bind its successors. All agreements of the Trustee in this
Indenture shall bind its successors.

SECTION 13.13.        SEPARABILITY.

                  In case any provision in this Indenture or in the Securities
shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby and a Holder shall have no claim therefor against any party
hereto.

SECTION 13.14.        TABLE OF CONTENTS, HEADINGS, ETC.

                  The Table of Contents, Cross-Reference Table and headings of
the Articles and Sections of this Indenture have been inserted for convenience
of reference only, are not to be considered a part hereof and shall in no way
modify or restrict any of the terms or provisions hereof.

<PAGE>

                                       S-1

                                   SIGNATURES

         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed as of the date first above written.

                                     GILEAD SCIENCES, INC.

                                     By:    /s/ John C. Martin
                                            ------------------------------------
                                            Name: John C. Martin
                                            Title: President and Chief Executive
                                            Officer

                                     THE CHASE MANHATTAN BANK AND TRUST
                                        COMPANY, NATIONAL ASSOCIATION,
                                        as Trustee

                                     By:    /s/ Rose T. Maravilla
                                            ------------------------------------
                                            Name: Rose T. Maravilla
                                            Title: Assistant Vice President

<PAGE>

                                                                       EXHIBIT A

REGISTERED                      [Face of Security]
NUMBER                                                                   DOLLARS

                              GILEAD SCIENCES, INC.

                   5% CONVERTIBLE SUBORDINATED NOTE DUE 2007

         GILEAD SCIENCES, INC., a Delaware corporation (herein called the
"COMPANY"), for value received, hereby promises to pay to          or
registered assigns, the principal sum of          Dollars on December 15, 2007,
and to pay interest thereon as provided on the reverse hereof on the
principal sum, until the principal hereof and any unpaid and accrued interest
is paid or duly provided for. The right to payment of principal, premium, if
any, and interest is subordinated to the rights of Senior Indebtedness as set
forth in the Indenture referred to on the reverse side hereof.

         Interest Payment Dates: June 15 and December 15, with the first payment
to be made on June 15, 2001.

         Record Dates: June 1 and December 1.

                                      A-1
<PAGE>

         IN WITNESS WHEREOF, GILEAD SCIENCES, INC. has caused this instrument to
be duly signed.

                                          GILEAD SCIENCES, INC.

                                          By:
                                              ----------------------------------
                                              Name:
                                              Title:

Dated:

TRUSTEE'S CERTIFICATE OF
   AUTHENTICATION

This is one of the Securities referred to
in the within-mentioned Indenture.

THE CHASE MANHATTAN BANK AND TRUST COMPANY,
  NATIONAL ASSOCIATION, as Trustee

By:
    ------------------------------------------------
               Authorized Officer

                                      A-2
<PAGE>

                              [REVERSE OF SECURITY]

                              GILEAD SCIENCES, INC.

                    5% CONVERTIBLE SUBORDINATED NOTE DUE 2007

         1.     INTEREST. Gilead Sciences, Inc., a Delaware corporation (the
"COMPANY"), promises to pay interest on the principal amount of this Security at
the rate PER ANNUM shown above. The Company will pay interest semi-annually in
arrears on June 15 and December 15 of each year, with the first payment to be
made on June 15, 2001. Interest on the Securities will accrue on the principal
amount from the most recent date to which interest has been paid or duly
provided for or, if no interest has been paid, from December 18, 2000. Interest
will be computed on the basis of a 360-day year of twelve 30-day months.

         2.     MATURITY. The Securities will mature on December 15, 2007 unless
earlier converted, redeemed or repurchased pursuant to the terms hereof and the
Indenture.

         3.     METHOD OF PAYMENT. The Company will pay interest on the
Securities (except defaulted interest) to the Persons who are registered Holders
of Securities at the close of business on the record date set forth on the face
of this Security next preceding the applicable interest payment date except that
(i) interest payable upon redemption or repurchase, unless the date of
redemption or repurchase is an interest payment date, will be payable to the
Person to whom the principal is payable and (ii) in the case of any Security or
portion of any Security that is converted into Common Stock during the period
from, but excluding, a record date for any interest payment date to, but
excluding, that interest payment date either (A) if the Security, or portion of
the Security, has been called for redemption on a redemption date that occurs
during that period, or is to be repurchased on a Repurchase Date that occurs
during that period, the Company will not be required to pay interest on that
interest payment date in respect of any Security, or portion of any Security,
that is so redeemed or repurchased; or (B) if otherwise, any Security or portion
of any Security that is not called for redemption but is submitted for
conversion during that period must be accompanied by funds equal to the interest
payable on that interest payment date on the principal amount so converted.
Holders must surrender Securities to a Paying Agent to collect the principal
payments. The Company will pay the principal, premium, if any, and interest in
money of the United States that at the time of payment is legal tender.
Principal and interest may, at the Company's option, be paid either (i) by check
mailed to the address of the Person entitled to the interest as it appears in
the register kept by the Registrar (provided (a) payments to the Depository will
be made by wire transfer of immediately available funds to the account of the
Depository or its nominee and (b) a Holder with an aggregate principal amount of
Securities in excess of $10 million will, at the written election of the Holder,
filed on or before the relevant record date with the Trustee, be paid by wire
transfer in immediately available funds); or (ii) by transfer to an account
maintained by that Person located in the U.S.

         4.     PAYING AGENT, REGISTRAR, CONVERSION AGENT. Initially, Chase
Manhattan Bank and Trust Company, National Association (the "TRUSTEE") will act
as Paying Agent, Registrar and Conversion Agent. The Company may change any
Paying Agent, Registrar or Conversion Agent without notice. The Company may act
in any such capacity.

                                      A-3
<PAGE>

         5.     INDENTURE. The Company issued the Securities under an
Indenture dated as of December 18, 2000 (the "INDENTURE") between the Company
and the Trustee. The terms of the Securities include those stated in the
Indenture and those made part of the Indenture by reference to the Trust
Indenture Act of 1939 (15 U.S. Code Sections 77aaa-77bbbb) (the "ACT") as in
effect on the date of the Indenture. The Securities are subject to all such
terms, and Holders are referred to the Indenture and the Act for a statement
of such terms. The Securities are general unsecured subordinated obligations
of the Company limited to a maximum of $250,000,000 aggregate principal
amount (plus such additional amount (up to an aggregate of $300,000,000)
purchased by the Initial Purchasers pursuant to the option described in
Section 2.02), except as otherwise provided in the Indenture (except for
Securities issued in substitution for destroyed, mutilated, lost or stolen
Securities). Terms used herein which are defined in the Indenture have the
meanings assigned to them in the Indenture.

         6.     OPTIONAL REDEMPTION BY THE COMPANY. At any time on or after
December 20, 2003, the Company may redeem the Securities on at least 30 days'
notice as a whole or, from time to time, in part at the following prices,
expressed as a percentage of the principal amount, together with accrued
interest to, but excluding, the date fixed for redemption:

<TABLE>
<CAPTION>
                                                                                        Redemption
Period                                                                                     Price
-------                                                                               --------------
<S>                                                                                   <C>
Beginning December 20, 2003 and ending on December 14, 2004........................      102.857%
Beginning December 15, 2004 and ending on December 14, 2005........................      102.143%
Beginning December 15, 2005 and ending on December 14, 2006........................      101.429%
Beginning December 15, 2006 and ending on December 14, 2007........................      100.714%
</TABLE>

Any accrued interest becoming due on the date fixed for redemption will be
payable to the holders of record on the relevant record date of the Securities
being redeemed.

         7.     NOTICE OF REDEMPTION. Notice of redemption pursuant to paragraph
6 will be mailed at least 30 days before the redemption date to each Holder of
Securities to be redeemed at its registered address. Securities in denominations
larger than $1,000 principal amount may be redeemed in part but only in whole
multiples of $1,000 principal amount. On and after the redemption date interest
ceases to accrue on Securities or portions of them called for redemption.

         8.     REPURCHASE AT OPTION OF HOLDER. Pursuant to Section 3.07 of the
Indenture within 15 days after a Repurchase Event occurs, the Company is
required to give notice of the Repurchase Event to the Holders. Each Holder has
the right, at its option, to require the Company to repurchase all or any
portion of the Securities 40 days after the notice of repurchase event is
mailed. The Repurchase Price will be 100% of the principal amount of the
Securities submitted for repurchase, plus accrued and unpaid interest to, but
excluding, the Repurchase Date. If a Repurchase Date is an interest payment
date, then the interest payable on that date will be paid to the holder of
record on the relevant record date. Subject to the conditions of Section 3.07 of
the Indenture, the Company, at its option, instead of paying the Repurchase
Price in cash, may pay the Repurchase Price in Common Stock, valued at 95% of
the average of the Closing Prices for the five Trading Days immediately before
and including the third Trading Day preceding the Repurchase Date.

         9.     CONVERSION. A Holder of a Security may convert the principal of
such Security into Common Stock at any time after the date of original issuance
of the Security to the close of business on the business day prior to December
15, 2007, or (x) if the Security is called for redemp-

                                      A-4
<PAGE>

tion by the Company, the Holder may convert it at any time before the close of
business on the date that is one business day before the date fixed for such
redemption, or (y) if the Security is to be repurchased by the Company pursuant
to paragraph 8 hereof, the Holder may convert it at any time before the close of
business on the date that is one business day before the date fixed for such
repurchase. The initial Conversion Price is $98.25 per share of Common Stock,
subject to adjustment in certain circumstances as set forth in Section 10.06 of
the Indenture. To determine the number of shares issuable upon conversion of a
Security, divide the principal amount to be converted by the Conversion Price in
effect on the conversion date and round the result to the nearest 1/100th share.
The Company is not required to issue fractional shares of Common Stock upon
conversion and, instead, will pay a cash amount as provided in Section 10.03 of
the Indenture. Except as provided in Article Ten of the Indenture, no payment or
adjustment for the principal of, premium, if any, interest on or liquidated
damages with respect to, the Securities or for dividends on any Common Stock
will be made. If a Holder surrenders a Security for conversion between the
record date for the payment of interest and the next interest payment date, such
Security, when surrendered for conversion, must be accompanied by payment of an
amount equal to the interest thereon which the registered Holder on such record
date is to receive. A Security which the Holder has elected to be repurchased
may be converted only if the Holder withdraws its election to have such Security
repurchased in accordance with the terms of the Indenture before the close of
business on the business day prior to the Repurchase Date.

         To convert a Security a Holder must (1) complete and sign the
Conversion Notice, with appropriate signature guarantee, on the back of the
Security, (2) surrender the Security to a Conversion Agent, (3) furnish
appropriate endorsements and transfer documents if required by the Registrar or
Conversion Agent, (4) pay the amount of interest, if any, the Holder may be paid
as provided in the last sentence of the above paragraph and (5) pay any transfer
or similar tax if required. A Holder may convert a portion of a Security if the
portion is $1,000 principal amount or a whole multiple of $1,000 principal
amount.

         Any shares issued upon conversion of a Security shall bear the Private
Placement Legend until after the second anniversary of the later of the issue
date for the Securities and the last date on which the Company or any Affiliate
of the Company was the owner of such shares or the Security (or any predecessor
security) from which such shares were converted (or such shorter period of time
as permitted by Rule 144(k) under the Securities Act or any successor provision
thereunder) (or such longer period of time as may be required under the
Securities Act or applicable state securities laws as set forth in the Opinion
of Counsel delivered to the Conversion Agent, unless otherwise agreed by the
Company and the Holder thereof).

         10.    SUBORDINATION. The Securities are subordinated in right of
payment, in the manner and to the extent set forth in the Indenture, to the
prior payment in full of all Senior Indebtedness. Each Holder by accepting a
Security agrees to such subordination and authorizes the Trustee to give it
effect.

         11.    DENOMINATIONS, TRANSFER, EXCHANGE. The Securities are in
registered form without coupons in denominations of $1,000 principal amount and
whole multiples of $1,000 principal amount. The transfer of Securities may be
registered and Securities may be exchanged as provided in the Indenture. The
Registrar may require a Holder, among other things, to furnish appropriate
endorsements and transfer documents. No service charge shall be made for any
such registration of transfer or exchange, but the Company may require payment
of a sum sufficient to cover any tax or other governmental charge payable in
connection therewith. The Registrar need not exchange or reg-

                                      A-5
<PAGE>

ister the transfer of any Security selected for redemption in whole or in part.
Also, it need not exchange or register the transfer of any Securities for a
period of 15 days before the mailing of a notice of redemption of the Securities
selected to be redeemed.

         12.    PERSONS DEEMED OWNERS. The registered Holder of a Security may
be treated as the owner of such Security for all purposes.

         13.    MERGER OR CONSOLIDATION. The Company shall not consolidate with,
or merge into, or transfer or lease all or substantially all of its assets to,
any Person unless, among other things, the Person is organized under the laws of
the United States, any State thereof or the District of Columbia and such Person
assumes by supplemental indenture all the obligations of the Company under the
Securities, the Indenture and the Registration Rights Agreement and after giving
effect to the transaction no Default or Event of Default exists.

         Notwithstanding the foregoing, any subsidiary of the Company may
consolidate with, merge into or transfer all or part of its properties and
assets to the Company or any other subsidiary or subsidiaries of the Company.

         14.    AMENDMENTS, SUPPLEMENTS AND WAIVERS. Subject to certain
exceptions, the Indenture or the Securities may be amended or supplemented with
the consent of the Holders of at least a majority in aggregate principal amount
of the Securities then outstanding, and any existing Default or Event of Default
may be waived with the consent of the Holders of a majority in aggregate
principal amount of the Securities then outstanding. Without notice to or the
consent of any Holder, the Indenture or the Securities may be amended or
supplemented to cure any ambiguity, omission, defect or inconsistency, to
provide for uncertificated Securities in addition to certificated Securities, to
comply with Sections 5.01 and 10.07 of the Indenture or to make any change that
does not adversely affect the rights of any Holder.

         15.    DEFAULTS AND REMEDIES. An Event of Default includes the
occurrence of any or the following: default in payment of the principal of or
any premium on the Securities; default for 30 days in payment of interest;
failure by the Company for 90 days after notice to it to comply with any of its
other agreements in the Indenture or the Securities; and certain events of
bankruptcy or insolvency. If any Event of Default occurs and is continuing, the
Trustee or the Holders of at least 25% in aggregate principal amount of the
Securities then outstanding may declare all the Securities to be due and
payable. Holders may not enforce the Indenture or the Securities except as
provided in the Indenture. The Trustee may require indemnity satisfactory to it
before it enforces the Indenture or the Securities. Subject to certain
limitations, Holders of a majority in principal amount of the Securities then
outstanding may direct the Trustee in its exercise of any trust or power. The
Trustee may withhold from Holders notice of any continuing Default or Event of
Default (except a Default or Event of Default in payment of principal or
interest) if it determines that withholding notice is in their interests. The
Company must furnish an annual compliance certificate to the Trustee.

         16.    REGISTRATION RIGHTS. The Holders are entitled to shelf
registration rights as set forth in the Registration Rights Agreement. The
Holders shall be entitled to receive liquidated damages in certain
circumstances, all as set forth in the Registration Rights Agreement.

         17.    TRUSTEE DEALINGS WITH COMPANY. The Trustee under the Indenture,
or any banking institution serving as successor Trustee thereunder, in its
individual or any other capacity,

                                      A-6
<PAGE>

may make loans to, accept deposits from, and perform services for the Company or
its Affiliates, and may otherwise deal with the Company or its Affiliates, as if
it were not Trustee.

         18.    NO RECOURSE AGAINST OTHERS. No past, present or future director,
officer, employee or stockholder, as such, of the Company shall have any
liability for any obligations of the Company under the Securities or the
Indenture or for any claim based on, in respect of or by reason of such
obligations or their creation. Each Holder by accepting a Security waives and
releases all such liability. The waiver and release are part of the
consideration for the issue of the Securities.

         19.    AUTHENTICATION. This Security shall not be valid until
authenticated by the manual signature of the Trustee or an authenticating agent.

         20.    ABBREVIATIONS. Customary abbreviations may be used in the name
of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entirety), JT TEN (= joint tenants with right of survivorship and
not as tenants in common), CUST (= Custodian), and U/G/M/A (Uniform Gifts to
Minors Act).

         THE COMPANY WILL FURNISH TO ANY SECURITYHOLDER UPON WRITTEN REQUEST AND
WITHOUT CHARGE A COPY OF THE INDENTURE. REQUESTS MAY BE MADE TO:

         GILEAD SCIENCES, INC.
         333 Lakeside Drive
         Foster City, California 94404

         ATTENTION:  Gregg Alton, Esq., General Counsel

                                      A-7

<PAGE>

                              [FORM OF ASSIGNMENT]

I or we assign to
PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER

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

--------------------------------------------------------------------------------
(please print or type name and address)

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

--------------------------------------------------------------------------------
the within Security and all rights thereunder, and hereby irrevocably
constitutes and appoints

--------------------------------------------------------------------------------
attorney to transfer the Security on the books of the Company with full power of
substitution in the premises.

Dated:
      ------------------------------------   -----------------------------------
                                             NOTICE: The signature on this
                                             assignment must correspond with the
                                             name as it appears upon the face of
                                             the within Security in every
                                             particular without alteration or
                                             enlargement or any change
                                             whatsoever and be guaranteed by the
                                             endorser's bank or broker.

Signature Guarantee:
                    ------------------------------------------------------------

         (Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Registrar, which requirements include membership
or participation in the Security Transfer Agent Medallion Program ("STAMP") or
such other "signature guarantee program" as may be determined by the Registrar
in addition to, or in substitution for, STAMP, all in accordance with the
Securities Exchange Act of 1934, as amended.)

         In connection with any transfer of this Security occurring prior to the
date which is the earlier of (i) the date of the declaration by the Commission
of the effectiveness of a registration statement under the Securities Act of
1933, as amended (the "SECURITIES ACT") covering resales of this Security (which
effectiveness shall have been suspended or terminated at the date of the
transfer) and (ii) December 17, 2002 the undersigned confirms that it has not
utilized any general solicitation or general advertising in connection with
transfer:

                                      A-8
<PAGE>

                                   [Check One]

<TABLE>
<S>   <C>        <C>
(1)    ____       to the Company or a subsidiary thereof; or

(2)    ____       pursuant to and in compliance with Rule 144A under the
                  Securities Act of 1933, as amended; or

(3)    ____       to an institutional "accredited investor" (as defined in Rule
                  501(a)(1), (2), (3) or (7) under the Securities Act of 1933,
                  as amended) that has furnished to the Trustee a signed letter
                  containing certain representations and agreements (the form of
                  which letter can be obtained from the Trustee); or

(4)    ____       outside the United States to a "foreign purchaser" in
                  compliance with Rule 904 of Regulation S under the Securities
                  Act of 1933, as amended; or

(5)    ____       pursuant to the exemption from registration provided by Rule
                  144 under the Securities Act of 1933, as amended; or

(6)    ____       pursuant to an effective registration statement under the
                  Securities Act of 1933, as amended; or

(7)    ____       pursuant to another available exemption from the registration
                  statement requirements of the Securities Act of 1933, as
                  amended.
</TABLE>

and unless the box below is checked, the undersigned confirms that such Security
is not being transferred to an "affiliate" of the Company as defined in Rule 144
under the Securities Act of 1933, as amended (an "AFFILIATE"):

         / /    The transferee is an Affiliate of the Company. (If the
Security is transferred to an Affiliate, the restrictive legend must remain
on the Security for two years following the date of the transfer).

         Unless one of the items is checked, the Trustee will refuse to
register any of the Securities evidenced by this certificate in the name of
any Person other than the registered Holder thereof; PROVIDED, HOWEVER, that
if item (3),(4),(5) or (7) is checked, the Company or the Trustee may
require, prior to registering any such transfer of the Securities, in their
sole discretion, such written legal opinions, certifications (including an
investment letter in the case of box (3) or (4)) and other information as the
Trustee or the Company have reasonably requested to confirm that such
transfer is being made pursuant to an exemption from, or in a transaction not
subject to, the registration requirements of the Securities Act of 1933, as
amended.

         If none of the foregoing items are checked, the Trustee or Registrar
shall not be obligated to register this Security in the name of any Person
other than the Holder hereof unless and until the conditions to any such
transfer of registration set forth herein and in Section 2.16 of the
Indenture shall have been satisfied.

                                      A-9
<PAGE>

Dated:                                     Signed:
      -------------------------------             ------------------------------
                                                     (Sign exactly as name
                                                     appears on the other side
                                                     of this Security)

Signature Guarantee:
                    ------------------------------------------------------------

TO BE COMPLETED BY PURCHASER IF (2) ABOVE IS CHECKED

         The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act
of 1933, as amended, and is aware that the sale to it is being made in
reliance on Rule 144A and acknowledges that it has received such information
regarding the Company as the undersigned has requested pursuant to Rule 144A
or has determined transferor is relying upon the undersigned's foregoing
representations in order to claim the exemption from registration provided by
Rule 144A.

Dated:
      ------------------------------------   -----------------------------------
                                             NOTICE:  To be executed by an
                                                      executive officer

                                      A-10
<PAGE>

                                CONVERSION NOTICE

To convert this Security into Common Stock of the Company, check the box:

/ /

To convert only part of this Security, state the principal amount to be
converted (must be in multiples of $1,000):

$
 -------------------------------------------------------------------------------

If you want the stock certificate made out in another person's name, fill in
the form below:

--------------------------------------------------------------------------------
(Insert other person's soc. sec. or tax I.D. no.)

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

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

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

--------------------------------------------------------------------------------
(Print or type other person's name, address and zip code)

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

Date:                   Signature(s):
     ----------------                 ------------------------------------------

                                      ------------------------------------------
                                      (Signatures must be guaranteed by an
                                      "eligible guarantor institution" meeting
                                      the requirements of the Registrar, which
                                      requirements include membership or
                                      participation in the Security Transfer
                                      Agent Medallion Program ("STAMP") or such
                                      other "signature guarantee program" as may
                                      be determined by the Registrar in addition
                                      to, or in substitution for, STAMP, all in
                                      accordance with the Securities Exchange
                                      Act of 1934, as amended.)

                                      A-11
<PAGE>

Signature(s)guaranteed by:
                          ------------------------------------------------------
                          (Signatures must be guaranteed by an "eligible
                          guarantor institution" meeting the requirements of the
                          Registrar, which requirements include membership or
                          participation in the Security Transfer Agent Medallion
                          Program ("STAMP") or such other "signature guarantee
                          program" as may be determined by the Registrar in
                          addition to, or in substitution for, STAMP, all in
                          accordance with the Securities Exchange Act of 1934,
                          as amended.)

                                      A-12
<PAGE>

                    OPTION OF HOLDER TO ELECT PURCHASE NOTICE

         If you want to elect to have this Security purchased by the Company
pursuant to Section 3.07 of the Indenture, check the box: / /

         If you want to elect to have only part of this Security purchased by
the Company pursuant to Section 3.07 of the Indenture, state the principal
amount:

                      $
                       ----------------------------------
                       (in an integral multiple of $1,000)

Date:                                 Signature(s):
     ----------------------------                  -----------------------------

                                      ------------------------------------------
                                      (Sign exactly as your name(s) appear(s) on
                                      the other side of this Security)

Signature(s) guaranteed by:
                                      ------------------------------------------
                                      (Signatures must be guaranteed by an
                                      "eligible guarantor institution" meeting
                                      the requirements of the Registrar, which
                                      requirements include membership or
                                      participation in the Security Transfer
                                      Agent Medallion Program ("STAMP") or such
                                      other "signature guarantee program" as may
                                      be determined by the Registrar in addition
                                      to, or in substitution for, STAMP, all in
                                      accordance with the Securities Exchange
                                      Act of 1934, as amended.)

                                      A-13

<PAGE>

                                                                       EXHIBIT B

                                 FORM OF LEGENDS

                           I. PRIVATE PLACEMENT LEGEND

         Each Security issued under the Indenture shall bear a legend (and any
common stock issued upon conversion of such Security shall bear a comparable
legend) substantially in the following form:

         THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A
     TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT
     OF 1933 (THE "SECURITIES ACT"), AND THIS SECURITY AND THE SHARES OF COMMON
     STOCK ISSUABLE UPON CONVERSION HEREOF MAY NOT BE OFFERED, SOLD OR OTHERWISE
     TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
     THEREFROM. EACH PURCHASER OF THIS SECURITY IS HEREBY NOTIFIED THAT THE
     SELLER OF THIS SECURITY MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS
     OF SECTION 5 OF THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

         THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE ISSUER HEREOF
     THAT (A) THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON
     CONVERSION HEREOF MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED,
     ONLY (I) IN THE UNITED STATES TO A PERSON WHOM THE SELLER REASONABLY
     BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER
     THE SECURITIES ACT) IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A,
     (II) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT
     PROVIDED BY RULE 144 THEREUNDER (IF AVAILABLE) OR (III) PURSUANT TO AN
     EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN EACH OF CASES
     (I) THROUGH (III) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY
     STATE OF THE UNITED STATES, AND (B) THE HOLDER WILL, AND EACH SUBSEQUENT
     HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS SECURITY FROM IT OF THE
     RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

                                      B-1
<PAGE>

                           II. GLOBAL SECURITY LEGEND

         Any Global Security authenticated and delivered hereunder shall bear a
legend (which would be in addition to any other legends required in the case of
a Restricted Security) in substantially the following form:

         THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
     HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A
     NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS SECURITY IS NOT
     EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN
     THE DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED
     IN THE INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER
     OF THIS SECURITY AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE
     DEPOSITORY OR BY A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER
     NOMINEE OF THE DEPOSITORY) MAY BE REGISTERED EXCEPT IN THE LIMITED
     CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
     THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
     COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT,
     AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN
     SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND
     ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
     BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE
     HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS
     THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN
     WHOLE, BUT NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF
     OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL
     SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
     RESTRICTIONS SET FORTH IN SECTION 2.16 OF THE INDENTURE.

                                      B-2
<PAGE>

                                                                       EXHIBIT C

                            Form of Certificate To Be
                          Delivered in Connection with
                    Transfers to Non-QIB Accredited Investors
                    -----------------------------------------

                                                                          [Date]

Chase Manhattan Bank and Trust Company,
  National Association
101 California Street, Suite 2725
San Francisco, California 94111

Attention:  Rose Maravilla

Ladies and Gentlemen:

         In connection with our proposed purchase of 5% Convertible Subordinated
Notes Due 2007 (the "SECURITIES") of Gilead Sciences, Inc. (the "COMPANY"), we
confirm that:

         1.     We have received a copy of the Offering Memorandum (the
     "OFFERING MEMORANDUM"), dated December 13, 2000, relating to the Securities
     and such other information as we deem necessary in order to make our
     investment decision. We acknowledge that we have read and agreed to the
     matters stated on page 1 of the Offering Memorandum and in the section
     entitled "Notice to Investors" of the Offering Memorandum, including the
     restrictions on duplication and circulation of the Offering Memorandum.

         2.     We understand that any subsequent transfer of the Securities is
     subject to certain restrictions and conditions set forth in this Indenture
     relating to the Securities (as described in the Offering Memorandum) and
     the undersigned agrees to be bound by, and not to resell, pledge or
     otherwise transfer the Securities except in compliance with, such
     restrictions and conditions and the Securities Act of 1933, as amended (the
     "SECURITIES ACT") and all applicable state securities laws.

         3.     We understand that the offer and sale of the Securities have not
     been registered under the Securities Act, and that the Securities may not
     be offered or sold except as permitted in the following sentence. We agree,
     on our own behalf and on behalf of any accounts for which we are acting as
     hereinafter stated, that if we should sell any Securities prior to the date
     that is two years after the original issuance of the Securities, we will do
     so only (i) to the Company or any of its subsidiaries, (ii) inside the
     United States in accordance with Rule 144A under the Securities Act to a
     "QUALIFIED INSTITUTIONAL BUYER" (as defined in Rule 144A under the
     Securities Act), (iii) inside the United States to an institutional
     "ACCREDITED INVESTOR" (as defined below) that, prior to such transfer,
     furnishes (or has furnished on its behalf by a U.S. broker-dealer) to the
     Trustee (as defined in the Indenture relating to the Securi-

                                      C-1
<PAGE>

     ties), a signed letter containing certain representations and agreements
     relating to the restrictions on transfer of the Securities (the form of
     which letter can be obtained from the Trustee), (iv) outside the United
     States in accordance with Rule 904 of Regulation S under the Securities
     Act, (v) pursuant to the exemption from registration provided by Rule 144
     under the Securities Act (if available), or (vi) pursuant to an effective
     registration statement under the Securities Act, and we further agree to
     provide to any person purchasing any of the Securities from us a notice
     advising such purchaser that resales of the Securities are restricted as
     stated herein.

         4.     We are not acquiring the Securities for or on behalf of, and
     will not transfer the Securities to, any pension or welfare plan (as
     defined in Section 3 of the Employee Retirement Income Security Act of
     1974), except as permitted by law.

         5.     We understand that, on any proposed resale of any Securities, we
     will be required to furnish to the Trustee and the Company such
     certification, legal opinions and other information as the Trustee and the
     Company may reasonably require to confirm that the proposed sale complies
     with the foregoing restrictions. We further understand that the Securities
     purchased by us will bear a legend to the foregoing effect.

         6.     We are an institutional "accredited investor" (as defined in
     Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act)
     and have such knowledge and experience in financial and business matters as
     to be capable of evaluating the merits and risks of our investment in the
     Securities, and we and any accounts for which we are acting are each able
     to bear the economic risk of our or their investment, as the case may be.

         7.     We are acquiring the Securities purchased by us for our account
     or for one or more accounts (each of which is an institutional "accredited
     investor") as to each of which we exercise sole investment discretion.

                                      C-2
<PAGE>

         You, the Company, the Trustee and others are entitled to rely upon this
letter and are irrevocably authorized to produce this letter or a copy hereof to
any interested party in any administrative or legal proceeding or official
inquiry with respect to the matters covered hereby.

                                      Very truly yours,

                                      [Name of Transferee]

                                      By:
                                          --------------------------------------
                                          Name:
                                          Title:

                                      C-3
<PAGE>

                                                                       EXHIBIT D

                       Form of Certificate To Be Delivered
                          in Connection with Transfers
                            Pursuant to Regulation S
                       -----------------------------------

                                                                          [Date]

Chase Manhattan Bank and Trust Company,
    National Association
101 California Street, Suite 2725
San Francisco, California 94111

Attention:  Rose Maravilla

                           Re:      Gilead Sciences, Inc. (the "Company")
                                    5% Convertible Subordinated Notes
                                    due 2007 (the "Securities")
                                    -------------------------------------
Ladies and Gentlemen:

         In connection with our proposed purchase of $ aggregate principal
amount of the Securities, we confirm that such purchase has been effected
pursuant to and in accordance with Regulation S under the U.S. Securities Act of
1933, as amended (the "SECURITIES ACT"), and, accordingly, we represent that:

         (1)(a) [We are not a U.S. person and are not acquiring the Securities
     for the account or benefit of any U.S. person]. [We are a U.S. person who
     purchased securities in a transaction that did not require registration
     under the Act.]

         (2)    We agree to resell the Securities only in accordance with the
     provisions of Regulation S, pursuant to registration under the Securities
     Act, or pursuant to an available exemption from registration; and we agree
     not to engage in hedging transactions with regard to such securities unless
     in compliance with the Securities Act.

----------------------------------------------
(a)     One of the two following sentences must be used.

                                      D-1
<PAGE>

         You, the Company and counsel for the Company are entitled to rely upon
this letter and are irrevocably authorized to produce this letter or a copy
hereof to any interested party in any administrative or legal proceedings or
official inquiry with respect to the matters covered hereby. Terms used in this
certificate have the meanings set forth in Regulation S.

                                       Very truly yours,

                                       [Name of Transferor]

                                       By:
                                              ----------------------------------
                                              Authorized Signature

                                      D-2
<PAGE>

                                                                       EXHIBIT E

         Form of Notice of Transfer Pursuant to Registration Statement
         -------------------------------------------------------------

                                                                          [Date]

Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, California 94404

Chase Manhattan Bank and Trust Company,
  National Association
101 California Street, Suite 2725
San Francisco, California 94111

Attention:  Rose Maravilla

         Re:      Gilead Sciences, Inc. (the "Company")
                  5% Convertible Subordinated Notes Due 2007
                      (The "Securities")
                  ------------------------------------------

Ladies and Gentlemen:

         Please be advised that _____________ has transferred $___________
aggregate principal amount of the Securities or __ shares of the Company's
common stock, $.001 par value per share, issuable on conversion of the
Securities ("Stock") pursuant to an effective Shelf Registration Statement on
Form S-3 (File No. 333- ) filed by the Company.

         We hereby certify that the prospectus delivery requirements, if any, of
the Securities Act of 1933 as amended, have been satisfied with respect to the
transfer described above and that the above-named beneficial owner of the
Securities or Stock is named as a "Selling Security Holder" in the Prospectus
dated or in amendments or supplements thereto, and that the aggregate principal
amount of the Securities, or number of shares of Stock transferred are [a
portion of] the Securities or Stock listed in such Prospectus, as amended or
supplemented, opposite such owner's name.

                                        Very truly yours,

                                        ----------------------------------------
                                                      (Name)

                                      D-3<PAGE>

                                                                     Exhibit 4.2

                          REGISTRATION RIGHTS AGREEMENT

                          Dated as of December 18, 2000

                                  By and Among

                             GILEAD SCIENCES, INC.,

                                    as Issuer

                                       and

                          J.P. MORGAN SECURITIES INC.,

                             CHASE SECURITIES INC.,

                              LEHMAN BROTHERS INC.

                                       and

                        MORGAN STANLEY & CO. INCORPORATED

                              as Initial Purchasers

                   5% Convertible Subordinated Notes Due 2007

<PAGE>

<TABLE>
<CAPTION>

                                TABLE OF CONTENTS

                                                                           PAGE
                                                                           ----
<S>   <C>                                                                    <C>
1.     Definitions............................................................1
2.     Shelf Registration.....................................................4
3.     Liquidated Damages.....................................................5
4.     Registration Procedures................................................7
5.     Registration Expenses.................................................14
6.     Indemnification.......................................................14
7.     Rules 144 and 144A....................................................18
8.     Underwritten Registrations............................................18
9.     Miscellaneous.........................................................18
       (a)    No Inconsistent Agreements.....................................18
       (b)    Adjustments Affecting Registrable Securities...................19
       (c)    Amendments and Waivers.........................................19
       (d)    Notices........................................................19
       (e)    Successors and Assigns.........................................20
       (f)    Counterparts...................................................20
       (g)    Headings.......................................................20
       (h)    Governing Law..................................................20
       (i)    Severability...................................................21
       (j)    Securities Held by the Company or Its Affiliates...............21
       (k)    Third Party Beneficiaries......................................21
       (l)    Entire Agreement...............................................21
</TABLE>

                                      -i-

<PAGE>

                          REGISTRATION RIGHTS AGREEMENT

            This Registration Rights Agreement (the "AGREEMENT") is dated as of
December 18, 2000, by and among GILEAD SCIENCES, INC., a Delaware corporation
(the "COMPANY"), J.P. MORGAN SECURITIES INC., CHASE SECURITIES INC., LEHMAN
BROTHERS INC. and MORGAN STANLEY & CO. INCORPORATED (individually, an "INITIAL
PURCHASER," and together, the "INITIAL PURCHASERS").

            This Agreement is entered into in connection with the Purchase
Agreement, dated as of December 13, 2000 (the "PURCHASE AGREEMENT"), by and
among the Company and the Initial Purchasers, which provides for the sale by the
Company to the Initial Purchasers of $250,000,000 aggregate principal amount of
the Company's 5% Convertible Subordinated Notes Due 2007 (the "FIRM NOTES"),
which are convertible into Common Stock of the Company, par value $.001 per
share (the "UNDERLYING SHARES"), plus up to an additional $50,000,000 aggregate
principal amount of the same which the Initial Purchasers may subsequently elect
to purchase pursuant to the terms of the Purchase Agreement (the "ADDITIONAL
NOTES" and together with the Firm Notes, the "CONVERTIBLE NOTES"). The Notes are
being issued pursuant to an indenture dated as of the date hereof (the
"INDENTURE"), between the Company and Chase Manhattan Bank and Trust Company,
National Association, as Trustee.

            In order to induce the Initial Purchasers to enter into the Purchase
Agreement, the Company has agreed to provide the registration rights set forth
in this Agreement for the benefit of the Initial Purchasers and any subsequent
holder or holders of the Convertible Notes or Underlying Shares. The execution
and delivery of this Agreement is a condition to the Initial Purchasers'
obligation to purchase the Firm Notes under the Purchase Agreement.

            The parties hereby agree as follows:

1.   DEFINITIONS.
     -----------

            As used in this Agreement, the following terms shall have the
following meanings:

            AGREEMENT: See the first introductory paragraph hereto.

            AMOUNT OF REGISTRABLE SECURITIES: (a) With respect to Convertible
Notes constituting Registrable Securities, the aggregate principal amount of all
such Convertible Notes outstanding, (b) with respect to Underlying Shares
constituting Registrable Securities, the aggregate number of such Underlying
Shares outstanding multiplied by the Conversion Price (as defined in the
Indenture relating to the Convertible Notes upon the conversion of which such
Underlying Shares were issued) in effect at the time of computing the Amount of
Registrable Securities or, if no such Convertible Notes are then outstanding,
the last Conversion Price that was in effect under such Indenture when any such
Convertible Notes were last outstanding,

<PAGE>

and (c) with respect to combinations thereof, the sum of (a) and (b) for the
relevant Registrable Securities.

            BUSINESS DAY: Any day that is not a Saturday, Sunday or a day on
which banking institutions in New York are authorized or required by law to be
closed.

            CLOSING DATE: December 18, 2000.

            COMPANY: See the first introductory paragraph hereto.

            CONVERTIBLE NOTES: See the second introductory paragraph hereto.

            COUNSEL TO THE HOLDERS: See Section 5(b) hereof.

            DAMAGES PAYMENT DATE: See Section 3(c) hereof.

            DEPOSITARY: The Depository Trust Company until a successor is
appointed by the Company.

            EFFECTIVENESS DATE: The 180th day after the Closing Date.

            EFFECTIVENESS PERIOD: See Section 2 hereof.

            EXCHANGE ACT: The Securities Exchange Act of 1934, as amended, and
the rules and regulations of the SEC promulgated thereunder.

            FILING DATE: The 90th day after the Closing Date.

            HOLDER: Any holder of Registrable Securities.

            INDEMNIFIED HOLDER: See Section 6 hereof.

            INDEMNIFIED PERSON: See Section 6 hereof.

            INDEMNIFYING PERSON: See Section 6 hereof.

            INDENTURE: See the second introductory paragraph hereto.

            INITIAL PURCHASERS: See the first introductory paragraph hereto.

            INITIAL SHELF REGISTRATION: See Section 2(a) hereof.

            INSPECTORS: See Section 4(n) hereof.

            LIQUIDATED DAMAGES: See Section 3(a) hereof.

                                      -2-

<PAGE>

            NASD: See Section 4(q) hereof.

            PERSON: An individual, partnership, corporation, limited liability
company, unincorporated association, trust or joint venture, or a governmental
agency or political subdivision thereof.

            PROSPECTUS: The prospectus included in any Registration Statement
(including, without limitation, any prospectus subject to completion and a
prospectus that includes any information previously omitted from a prospectus
filed as part of an effective registration statement in reliance upon Rule 430A
promulgated under the Securities Act), as amended or supplemented by any
prospectus supplement, and all other amendments and supplements to the
Prospectus, including post-effective amendments, and all material incorporated
by reference or deemed to be incorporated by reference in such Prospectus.

            PURCHASE AGREEMENT: See the second introductory paragraph hereto.

            RECORDS: See Section 4(n) hereof.

            REGISTRABLE SECURITIES: All Convertible Notes and all Underlying
Shares upon original issuance thereof and at all times subsequent thereto until
the earliest to occur of (i) a Registration Statement covering such Convertible
Notes and Underlying Shares having been declared effective by the SEC and such
Convertible Notes and Underlying Shares have been disposed of in accordance with
such effective Registration Statement, (ii) such Convertible Notes and
Underlying Shares having been sold in compliance with Rule 144 or could (except
with respect to affiliates of the Company within the meaning of the Securities
Act) be sold in compliance with Rule 144(k), or (iii) such Convertible Notes and
any Underlying Shares cease to be outstanding.

            REGISTRATION DEFAULT: See Section 3(a) hereof.

            REGISTRATION STATEMENT: Any registration statement of the Company
filed with the SEC pursuant to the provisions of this Agreement, including the
Prospectus, amendments and supplements to such registration statement, including
post-effective amendments, all exhibits and all material incorporated by
reference or deemed to be incorporated by reference in such registration
statement.

            RULE 144: Rule 144 promulgated under the Securities Act, as such
Rule may be amended from time to time, or any similar rule (other than Rule
144A) or regulation hereafter adopted by the SEC providing for offers and sales
of securities made in compliance therewith resulting in offers and sales by
subsequent holders that are not affiliates of an issuer of such securities being
free of the registration and prospectus delivery requirements of the Securities
Act.

                                      -3-

<PAGE>

            RULE 144A: Rule 144A promulgated under the Securities Act, as such
Rule may be amended from time to time, or any similar rule (other than Rule 144)
or regulation hereafter adopted by the SEC.

            RULE 415: Rule 415 promulgated under the Securities Act, as such
Rule may be amended from time to time, or any similar rule or regulation
hereafter adopted by the SEC.

            SEC: The Securities and Exchange Commission.

            SECURITIES ACT: The Securities Act of 1933, as amended, and the
rules and regulations of the SEC promulgated thereunder.

            SHELF REGISTRATION: See Section 2(b) hereof.

            SHELF REGISTRATION STATEMENT: See Section 2(b) hereof.

            SUBSEQUENT SHELF REGISTRATION: See Section 2(b) hereof.

            TIA: The Trust Indenture Act of 1939, as amended, and the rules and
regulations of the SEC promulgated thereunder.

            TRUSTEE: The Trustee under the Indenture.

            UNDERLYING SHARES: See the second introductory paragraph hereto.

            UNDERWRITTEN REGISTRATION OR UNDERWRITTEN OFFERING: A registration
in which securities of the Company are sold to an underwriter for reoffering to
the public.

2.   SHELF REGISTRATION

            (a)   SHELF REGISTRATION. The Company shall as promptly as
reasonably practicable file with the SEC a Registration Statement for an
offering to be made on a continuous basis pursuant to Rule 415 covering all of
the Registrable Securities (the "INITIAL SHELF REGISTRATION"). The Company shall
use its reasonable best efforts to file with the SEC the Initial Shelf
Registration on or prior to the Filing Date. The Initial Shelf Registration
shall be on Form S-3 or another appropriate form permitting registration of such
Registrable Securities for resale by Holders in the manner or manners designated
by them (including, without limitation, one or more underwritten offerings). The
Company shall not permit any securities other than the Registrable Securities to
be included in the Initial Shelf Registration or any Subsequent Shelf
Registration (as defined below).

            The Company shall use its reasonable best efforts to cause the
Initial Shelf Registration to be declared effective under the Securities Act on
or prior to the Effectiveness Date and to keep such Initial Shelf Registration
continuously effective under the Securities

                                      -4-

<PAGE>

Act until the date that is two years from the Closing Date (as it may be
shortened pursuant to clause (i) or clause (ii) immediately following, the
"EFFECTIVENESS PERIOD"), or such shorter period ending when (i) all the shares
of Registrable Securities covered by the Initial Shelf Registration have been
sold in the manner set forth and as contemplated in the Initial Shelf
Registration, (ii) the date on which all the Registrable Securities (x) held by
Persons who are not affiliates of the Company may be resold pursuant to Rule
144(k) under the Securities Act or (y) cease to be outstanding, or (iii) a
Subsequent Shelf Registration covering all of the Registrable Securities has
been declared effective under the Securities Act.

            (b)   SUBSEQUENT SHELF REGISTRATIONS. If the Initial Shelf
Registration or any Subsequent Shelf Registration ceases to be effective for any
reason at any time during the Effectiveness Period (other than because of the
sale of all of the securities registered thereunder), the Company shall use its
reasonable best efforts to obtain the prompt withdrawal of any order suspending
the effectiveness thereof, and in any event shall within 45 days of such
cessation of effectiveness amend the Initial Shelf Registration in a manner to
obtain the withdrawal of the order suspending the effectiveness thereof, or file
an additional "shelf" Registration Statement pursuant to Rule 415 covering all
of the Registrable Securities (a "SUBSEQUENT SHELF REGISTRATION"). If a
Subsequent Shelf Registration is filed, the Company shall use its reasonable
best efforts to cause the Subsequent Shelf Registration to be declared effective
under the Securities Act as soon as practicable after such filing and to keep
such Registration Statement continuously effective for a period equal to the
number of days in the Effectiveness Period less the aggregate number of days
during which the Initial Shelf Registration or any Subsequent Shelf Registration
was previously continuously effective. As used herein the term "SHELF
REGISTRATION" means the Initial Shelf Registration and any Subsequent Shelf
Registration and the term "SHELF REGISTRATION STATEMENT" means any Registration
Statement filed in connection with a Shelf Registration.

            (c)   SUPPLEMENTS AND AMENDMENTS. The Company shall promptly
supplement and amend the Shelf Registration if required by the rules,
regulations or instructions applicable to the registration form used for such
Shelf Registration, if required by the Securities Act, or if reasonably
requested by the Holders of the majority in Amount of Registrable Securities
covered by such Registration Statement or by any underwriter of such Registrable
Securities.

3.   LIQUIDATED DAMAGES

            (a)   The Company and the Initial Purchasers agree that the Holders
of Registrable Securities will suffer damages if the Company fails to fulfill
its obligations under Section 2 hereof and that it would not be feasible to
ascertain the extent of such damages with precision. Accordingly, the Company
agrees to pay liquidated damages on the Registrable Securities ("LIQUIDATED
DAMAGES") under the circumstances and to the extent set forth below (each of
which shall be given independent effect; each a "REGISTRATION DEFAULT"):

                                      -5-

<PAGE>

            (i)   if the Initial Shelf Registration is not filed on or prior to
the Filing Date, then commencing on the day after the Filing Date, Liquidated
Damages shall accrue on the Registrable Securities at a rate of 0.50% per annum
on the Amount of Registrable Securities for the first 90 days immediately
following the Filing Date, such Liquidated Damages increasing by an additional
0.50% per annum at the beginning of each subsequent 90-day period;

            (ii)  if the Initial Shelf Registration is not declared effective by
the SEC on or prior to the Effectiveness Date, then commencing on day after the
Effectiveness Date, Liquidated Damages shall accrue on the Registrable
Securities at a rate of 0.50% per annum on the Amount of Registrable Securities
for the first 90 days immediately following the day after such Effectiveness
Date, such Liquidated Damages increasing by an additional 0.50% per annum at the
beginning of each subsequent 90-day period; and

            (iii) if a Shelf Registration has been declared effective and such
Shelf Registration ceases to be effective at any time during the Effectiveness
Period (other than as permitted under Section 3(b)), then Liquidated Damages
shall accrue on the Registrable Securities at a rate of 0.50% per annum on the
Amount of Registrable Securities for the first 90 days commencing on the day
such Shelf Registration ceases to be effective, such Liquidated Damages
increasing by an additional 0.50% per annum at the beginning of each such
subsequent 90-day period;

PROVIDED, HOWEVER, that Liquidated Damages on the Registrable Securities may not
accrue under more than one of the foregoing clauses (i), (ii) or (iii) at any
one time and at no time shall the aggregate amount of Liquidated Damages
accruing exceed in the aggregate 1.0% per annum of the Amount of Registrable
Securities; PROVIDED, FURTHER, HOWEVER, that (1) upon the filing of the Shelf
Registration as required hereunder (in the case of clause (a)(i) of this Section
3), (2) upon the effectiveness of the Shelf Registration as required hereunder
(in the case of clause (a)(ii) of this Section 3), or (3) upon the effectiveness
of a Shelf Registration which had ceased to remain effective (in the case of
(a)(iii) of this Section 3), Liquidated Damages on the Registrable Securities as
a result of such clause (or the relevant subclause thereof), as the case may be,
shall cease to accrue. It is understood and agreed that, notwithstanding any
provision to the contrary, (i) so long as any Registrable Security is then
covered by an effective Shelf Registration Statement, no Liquidated Damages
shall accrue on such Registrable Security and (ii) no Holder shall be entitled
to Liquidated Damages hereunder unless such Holder has complied with its
obligations to furnish the information required by the second paragraph of
Section 4(s) hereof. The Liquidated Damages provided for in this Section 3 shall
be a Holder's exclusive remedy in the event of a Registration Default.

            (b)   Notwithstanding paragraph (a) of this Section 3, the Company
shall be permitted to suspend the effectiveness of a Shelf Registration for up
to 30 consecutive days in any 90 day period, for a total of not more than 60
days in any 365 day period, without paying Liquidated Damages.

                                      -6-

<PAGE>

            (c)   So long as Convertible Notes remain outstanding, the Company
shall notify the Trustee within two Business Days after each and every date on
which an event occurs in respect of which Liquidated Damages is required to be
paid. Any amounts of Liquidated Damages due pursuant to (a)(i), (a)(ii) or
(a)(iii) of this Section 3 will be payable in cash semi-annually on each May 15
and December 15 (each a "DAMAGES PAYMENT DATE"), commencing with the first such
date occurring after any such Liquidated Damages commences to accrue, to Holders
to whom regular interest is payable on such Damages Payment Date with respect to
Convertible Notes that are Registrable Securities and to Persons that are
registered Holders 15 days prior to such Damages Payment Date with respect to
Underlying Shares that are Registrable Securities. The amount of Liquidated
Damages for Registrable Securities will be determined by multiplying the
applicable rate of Liquidated Damages by the Amount of Registrable Securities
outstanding on the Damages Payment Date following such Registration Default in
the case of the first such payment of Liquidated Damages with respect to a
Registration Default (and thereafter at the next succeeding Damages Payment Date
until the cure of such Registration Default), multiplied by a fraction, the
numerator of which is the number of days such Liquidated Damages rate was
applicable during such period (determined on the basis of a 360-day year
comprised of twelve 30-day months and, in the case of a partial month, the
actual number of days elapsed), and the denominator of which is 360.

4.    REGISTRATION PROCEDURES

            In connection with the filing of any Registration Statement pursuant
to Section 2 hereof, the Company shall effect such registrations to permit the
resale of the securities covered thereby in accordance with the intended method
or methods of disposition thereof, and pursuant thereto and in connection with
any Registration Statement filed by the Company hereunder the Company shall:

            (a)   Prepare and file with the SEC on or prior to the Filing Date,
a Registration Statement or Registration Statements as prescribed by Section 2
hereof, and use its reasonable best efforts to cause each such Registration
Statement to become effective and remain effective as provided herein; PROVIDED,
HOWEVER, that before filing any Registration Statement or Prospectus or any
amendments or supplements thereto, the Company shall furnish to and afford the
Holders of the Registrable Securities that have provided the information
required by the second paragraph of Section 4(s), Counsel to the Holders and the
managing underwriters, if any, a reasonable opportunity to review copies of all
such documents proposed to be filed (in each case, where possible, at least five
Business Days prior to such filing, or such later date as is reasonable under
the circumstances). The Company shall not file any Registration Statement or
Prospectus or any amendments or supplements thereto if the Holders of a majority
in Amount of Registrable Securities that have provided the information required
by the second paragraph of Section 4(s), Counsel to the Holders or the managing
underwriters, if any, shall reasonably object.

                                      -7-

<PAGE>

            (b)   Prepare and file with the SEC such amendments and
post-effective amendments to each Shelf Registration, as may be necessary to
keep such Registration Statement continuously effective for the Effectiveness
Period; cause the related Prospectus to be supplemented by any Prospectus
supplement required by applicable law, and as so supplemented to be filed
pursuant to Rule 424 (or any similar provisions then in force) promulgated under
the Securities Act; and comply with the provisions of the Securities Act and the
Exchange Act applicable to it with respect to the disposition of all securities
covered by such Registration Statement as so amended or in such Prospectus as so
supplemented. The Company shall be deemed not to have used its reasonable best
efforts to keep a Registration Statement effective during the Effectiveness
Period if it voluntarily takes any action that would result in selling Holders
of the Registrable Securities covered thereby not being able to sell such
Registrable Securities during that period unless such action is required by
applicable law or unless the Company complies with this Agreement, including
without limitation the provisions of Sections 3(b) and 4(k) hereof.

            (c)   Notify the selling Holders of Registrable Securities (which
Holders shall have provided the information required pursuant to the second
paragraph of Section 4(s) hereof), Counsel to the Holders and the managing
underwriters, if any, promptly (but in any event within two Business Days) and,
if requested by such persons, confirm such notice in writing, (i) when a
Prospectus or any prospectus supplement or post-effective amendment has been
filed, and, with respect to a Registration Statement or any post-effective
amendment, when the same has become effective under the Securities Act
(including in such notice a written statement that any Holder may, upon request,
obtain, at the sole expense of the Company, one conformed copy of such
Registration Statement or post-effective amendment including financial
statements and schedules, documents incorporated or deemed to be incorporated by
reference and exhibits), (ii) of the issuance by the SEC of any stop order
suspending the effectiveness of a Registration Statement or of any order
preventing or suspending the use of any preliminary prospectus or the initiation
of any proceedings for that purpose, (iii) of the happening of any event, the
existence of any condition or any information becoming known that makes any
statement made in such Registration Statement or related Prospectus or any
document incorporated or deemed to be incorporated therein by reference untrue
in any material respect or that requires the making of any changes in or
amendments or supplements to such Registration Statement, Prospectus or
documents so that, in the case of the Registration Statement, it will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein
not misleading, and that in the case of the Prospectus, it will not contain any
untrue statement of a material fact or omit to state any material fact required
to be stated therein or necessary to make the statements therein, in the light
of the circumstances under which they were made, not misleading and (iv) of the
Company's determination that a post-effective amendment to a Registration
Statement would be appropriate.

            (d)   Use its reasonable best efforts to prevent the issuance of any
order suspending the effectiveness of a Registration Statement or of any order
preventing or suspending

                                      -8-

<PAGE>

the use of a Prospectus and, if any such order is issued, to use its reasonable
best efforts to obtain the withdrawal of any such order at the earliest possible
moment.

            (e)   In the event of an underwritten offering pursuant to the terms
of this Agreement, if requested by the managing underwriter or underwriters (if
any) or the Holders of the majority in Amount of Registrable Securities being
sold in connection with such underwritten offering (i) promptly incorporate in a
prospectus supplement or, if required, a post-effective amendment such
information as the managing underwriter or underwriters (if any), such Holders
or counsel for any of them reasonably determine is necessary to be included
therein, (ii) make all required filings of such prospectus supplement or such
post-effective amendment as soon as reasonably practicable after the Company has
received notification of the matters to be incorporated in such prospectus
supplement or post-effective amendment and (iii) supplement or make amendments
to such Registration Statement.

            (f)   Make available to each selling Holder of Registrable
Securities who so requests, Counsel to the Holders and each managing
underwriter, if any, at the sole expense of the Company, one conformed copy of
the Registration Statement or Registration Statements and each post-effective
amendment thereto, including financial statements and schedules, and all
documents incorporated or deemed to be incorporated therein by reference and all
exhibits.

            (g)   Deliver to each selling Holder of Registrable Securities,
Counsel to the Holders and the underwriters, if any, at the sole expense of the
Company, as many copies of the Prospectus (including each form of preliminary
prospectus) and each amendment or supplement thereto and any documents
incorporated by reference therein as such Persons may reasonably request; and,
subject to compliance by selling Holders with the second paragraph of Section
4(s) hereof, the Company hereby consents to the use of such Prospectus and each
amendment or supplement thereto in accordance with this Agreement by each of the
selling Holders of Registrable Securities and the underwriters or agents, if
any, and dealers (if any), in connection with the offering and sale of the
Registrable Securities covered by such Prospectus and any amendment or
supplement thereto.

            (h)   Prior to any public offering of Registrable Securities, to use
its reasonable best efforts to register or qualify, to the extent required by
applicable law, and to cooperate with the selling Holders of Registrable
Securities, the managing underwriter or underwriters, if any, and their
respective counsel in connection with the registration or qualification (or
exemption from such registration or qualification) of such Registrable
Securities or offer and sale under the securities or Blue Sky laws of such
jurisdictions within the United States as any selling Holder, or the managing
underwriter or underwriters, if any, reasonably request; PROVIDED, HOWEVER, that
where Registrable Securities are offered other than through an underwritten
offering, the Company agrees to cause the Company's counsel to perform Blue Sky
investigations and file registrations and qualifications required to be filed
pursuant to this Section 4(h); keep each such registration or qualification (or
exemption therefrom) effective during the period such Registration Statement is
required to be kept effective and do any and

                                      -9-

<PAGE>

all other acts or things reasonably necessary or advisable to enable the
disposition in such jurisdictions of the Registrable Securities covered by the
applicable Registration Statement; PROVIDED, HOWEVER, that the Company shall not
be required to (A) qualify generally to do business in any jurisdiction where it
is not then so qualified, (B) take any action that would subject it to general
service of process in any such where it is not then so subject or (C) subject
itself to taxation in excess of a nominal dollar amount in any such jurisdiction
where it is not then so subject.

            (i)   Cooperate with the selling Holders of Registrable Securities
and the managing underwriter or underwriters, if any, to facilitate the timely
preparation and delivery of certificates representing shares of Registrable
Securities to be sold, which certificates, when such Registrable Securities are
sold pursuant to the Shelf Registration Statement, shall not bear any
restrictive legends and shall be in a form eligible for deposit with The
Depository Trust Company; and enable such shares of Registrable Securities to be
in such denominations and registered in such names as the managing underwriter
or underwriters, if any, or Holders may reasonably request.

            (j)   Use its reasonable best efforts to cause the Registrable
Securities covered by any Shelf Registration Statement to be registered with or
approved by such other governmental agencies or authorities as may be reasonably
necessary to enable the seller or sellers thereof or the underwriter or
underwriters, if any, to consummate the disposition of such Registrable
Securities, except as may be required solely as a consequence of the nature of
such selling Holder's business, in which case the Company will cooperate in all
reasonable respects with the filing of such Registration Statement and the
granting of such approvals.

            (k)   Upon the occurrence of any event contemplated by paragraph
4(c)(ii), 4(c)(iii) or 4(c)(iv) hereof, as promptly as practicable prepare and
(subject to Section 4(a) hereof) file with the SEC, at the sole expense of the
Company, a supplement or post-effective amendment to the Registration Statement
or a supplement to the related Prospectus or any document incorporated or deemed
to be incorporated therein by reference, or file any other required document so
that, as thereafter delivered to the purchasers of the Registrable Securities
being sold thereunder, any such Prospectus will not contain an untrue statement
of a material fact or omit to state a material fact required to be stated
therein or necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading.

            (l)   Prior to the effective date of the first Registration
Statement relating to the Registrable Securities, (i) provide the Trustee with
certificates for the Registrable Securities in a form eligible for deposit with
The Depository Trust Company and (ii) provide required CUSIP numbers for the
Registrable Securities.

            (m)   In connection with any underwritten offering of Registrable
Securities pursuant to a Shelf Registration, enter into an underwriting
agreement as is customary in un-

                                      -10-

<PAGE>

derwritten offerings of securities similar to the Registrable Securities and
take all such other actions as are reasonably requested by the managing
underwriter or underwriters in order to expedite or facilitate the
registration or the disposition of such Registrable Securities and, in such
connection, (i) make such representations and warranties to, and covenants
with, the underwriters with respect to the business of the Company and its
subsidiaries (including any acquired business, properties or entity, if
applicable) and the Registration Statement, Prospectus and documents, if any,
incorporated or deemed to be incorporated by reference therein, in each case,
as are customarily made by issuers to underwriters in underwritten offerings
of securities similar to the Registrable Securities and confirm the same in
writing if and when requested; (ii) obtain the written opinion of counsel to
the Company and written updates thereof in form, scope and substance
reasonably satisfactory to the managing underwriter or underwriters,
addressed to the underwriters covering the matters customarily covered in
opinions requested in underwritten offerings of securities similar to the
Registrable Securities and such other matters as may be reasonably requested
by the managing underwriter or underwriters; and (iii) obtain "cold comfort"
letters and updates thereof in form, scope and substance reasonably
satisfactory to the managing underwriter or underwriters from the independent
certified public accountants of the Company (and, if necessary, any other
independent certified public accountants of any subsidiary of the Company or
of any business acquired by the Company for which financial statements and
financial data are, or are required to be, included or incorporated by
reference in the Registration Statement), addressed to each of the
underwriters, such letters to be in customary form and covering matters of
the type customarily covered in "cold comfort" letters in connection with
underwritten offerings of securities similar to the Registrable Securities
and such other matters as reasonably requested by the managing underwriter or
underwriters as permitted by the Statement on Auditing Standards No. 72. The
above shall be done as and to the extent required by such underwriting
agreement.

            (n)   Make available for inspection by any selling Holder of such
Registrable Securities being sold, any underwriter participating in any such
disposition of Registrable Securities, if any, and any attorney, accountant or
other agent retained by any such selling Holder, or underwriter (collectively,
the "INSPECTORS"), at the offices where normally kept, during reasonable
business hours at such time or times as shall be mutually convenient for the
Company and the Inspectors as a group, all financial and other records,
pertinent corporate documents and instruments of the Company and its
subsidiaries (collectively, the "RECORDS") as shall be reasonably necessary to
enable them to exercise any applicable due diligence responsibilities, and cause
the officers, directors and employees of the Company and its subsidiaries to
supply all information reasonably requested by any such Inspector in connection
with such Registration Statement. Records that the Company determines, in good
faith, to be confidential and any Records that it notifies the Inspectors are
confidential shall not be disclosed or used by any Inspector unless (i) the
disclosure of such Records is necessary to avoid or correct a material
misstatement or material omission in such Registration Statement, (ii) the
release of such Records is ordered pursuant to a subpoena or other order from a
court of competent jurisdiction, (iii) disclosure of such information is made in
a court proceeding or required by law or (iv) the information in such Records
has been made generally available to the

                                      -11-

<PAGE>

public other than through the acts of such Inspector or as a result of a breach
of this Agreement; PROVIDED, HOWEVER, that prior notice shall be provided as
soon as practicable to the Company of the potential disclosure of any
information by such Inspector pursuant to clauses (ii) or (iii) of this sentence
to permit the Company to obtain a protective order (or waive the provisions of
this paragraph (n)) and that such Inspector shall take such actions as are
reasonably necessary to protect the confidentiality of such information (if
practicable) to the extent such action is otherwise not inconsistent with, an
impairment of or in derogation of the rights and interests of any Holder or
Inspector; PROVIDED, FURTHER, that prior to the disclosure to any Inspector of
any Records that the Company determines, in good faith, to be confidential, the
Company may require such Inspector to execute a confidentiality agreement
whereby such Inspector shall agree to the limitations on the disclosure of the
Record to the extent provided above.

            (o)   Provide (i) the Holders of the Registrable Securities to be
included in such Registration Statement and Counsel to the Holders, (ii) the
underwriters (which term, for purposes of this Registration Rights Agreement,
shall include a Person deemed to be an underwriter within the meaning of Section
2(11) of the Securities Act), if any, thereof, (iii) the sales or placement
agent, if any, thereof, and (iv) one counsel for such underwriters or agents,
reasonable opportunity to participate in the preparation of such Registration
Statement, each prospectus included therein or filed with the SEC, and each
amendment or supplement thereto.

            (p)   Comply with all applicable rules and regulations of the SEC
and make generally available to its securityholders earning statements
satisfying the provisions of Section 11(a) of the Securities Act and Rule 158
thereunder (or any similar rule promulgated under the Securities Act) no later
than 45 days after the end of any 12-month period (or 90 days after the end of
any 12-month period if such period is a fiscal year) (i) commencing at the end
of any fiscal quarter in which Registrable Securities are sold to underwriters
in a firm commitment or best efforts underwritten offering and (ii) if not sold
to underwriters in such an offering, commencing on the first day of the first
fiscal quarter of the Company after the effective date of a Registration
Statement, which statements shall cover said 12-month periods.

            (q)   Cooperate with each seller of Registrable Securities covered
by any Registration Statement and each underwriter, if any, participating in the
disposition of such Registrable Securities and their respective counsel in
connection with any filings required to be made with the National Association of
Securities Dealers, Inc. (the "NASD"), including, if the Conduct Rules of the
NASD or any successor thereto as amended from time to time so require, engaging
a "qualified independent underwriter" ("QIU") as contemplated therein and making
Records available to such QIU as though it were a participating underwriter for
the purposes of Section 4(n) and otherwise applying the provisions of this
Agreement to such QIU (including indemnification) as though it were a
participating underwriter.

                                      -12-

<PAGE>

            (r)   Cause the Indenture to be qualified under the TIA not later
than the effective date of the first Registration Statement relating to the
Registrable Securities; and in connection therewith, cooperate with the Trustee
and the Holders of the Registrable Securities to effect such changes to the
Indenture as may be required for the Indenture to be so qualified in accordance
with the terms of the TIA; and execute, and use its reasonable best efforts to
cause the Trustee to execute, all documents as may be required to effect such
changes and all other forms and documents required to be filed with the SEC to
enable the Indenture to be so qualified in a timely manner.

            (s)   Use its reasonable best efforts to take all other steps
necessary or advisable to effect the registration of the Registrable Securities
covered by a Registration Statement contemplated hereby.

            The Company may require each seller of Registrable Securities as to
which any registration is being effected to furnish to the Company such
information regarding such seller and the distribution of such Registrable
Securities as the Company may, from time to time, reasonably request to the
extent necessary or advisable to comply with the Securities Act. The Company may
exclude from such registration the Registrable Securities of any seller if such
seller fails to furnish such information within 20 Business Days after receiving
such request. Each seller as to which any Shelf Registration is being effected
agrees to furnish promptly to the Company all information required to be
disclosed so that the information previously furnished to the Company by such
seller is not materially misleading and does not omit to state any material fact
required to be stated therein or necessary to make the statements therein not
misleading in light of the circumstances under which they were made.

            After the effective date of the Registration Statement, the Company
shall, upon the request of any Holder of Registrable Securities that has not
provided the information pursuant to the foregoing paragraph, send to such
Holder, in customary form, a request for such information. The Company shall not
be required to take any action to name such Holder as a selling securityholder
in the Registration Statement until such Holder has provided such information.
Following its receipt of such information, the Company will reasonably promptly,
and not later than five (5) business days after such receipt, include the
Registrable Securities covered thereby in the Registration Statement and shall
prepare, file and make available to such Holder the Prospectus and any required
prospectus supplement.

            Each Holder of Registrable Securities agrees by acquisition of such
Registrable Securities that, upon actual receipt of any notice from the Company
of the happening of any event of the kind described in Section 4(c)(ii),
4(c)(iii) or 4(c)(iv) hereof, such Holder will forthwith discontinue disposition
of such Registrable Securities covered by such Registration Statement or
Prospectus until such Holder's receipt of the copies of the supplemented or
amended Prospectus contemplated by Section 4(k) hereof, or until it is advised
in writing by the Company that the use of the applicable Prospectus may be
resumed, and has received copies of any amendments or supplements thereto.

                                      -13-

<PAGE>

5.    REGISTRATION EXPENSES

            (a)   All fees and expenses incident to the performance of or
compliance with this Agreement by the Company shall be borne by the Company,
including, without limitation, (i) all registration and filing fees (including,
without limitation, (A) fees with respect to filings required to be made with
the NASD in connection with an underwritten offering and (B) fees and expenses
of compliance with state securities or Blue Sky laws (including, without
limitation, reasonable fees and disbursements of counsel in connection with Blue
Sky qualifications of the Registrable Securities and determination of the
eligibility of the Registrable Securities for investment under the laws of such
jurisdictions as provided in Section 4(h) hereof), (ii) printing expenses,
including, without limitation, expenses of printing certificates for Registrable
Securities in a form eligible for deposit with The Depository Trust Company and
of printing prospectuses if the printing of prospectuses is requested by the
managing underwriter or underwriters, if any, or by the Holders of the majority
in Amount of Registrable Securities included in any Registration Statement,
(iii) messenger, telephone and delivery expenses, (iv) fees and disbursements of
counsel for the Company and reasonable fees and disbursements of special counsel
for the sellers of Registrable Securities (subject to the provisions of Section
5(b) hereof), (v) fees and disbursements of all independent certified public
accountants referred to in Section 4(m)(iii) hereof (including, without
limitation, the expenses of any special audit and "cold comfort" letters
required by or incident to such performance), (vi) Securities Act liability
insurance, if the Company desires such insurance, (vii) fees and expenses of all
other Persons retained by the Company, (viii) internal expenses of the Company
(including, without limitation, all salaries and expenses of officers and
employees of the Company performing legal or accounting duties), (ix) the
expense of any annual audit, (x) the fees and expenses incurred in connection
with the listing of the securities to be registered on any securities exchange,
if applicable, and (xi) the expenses relating to printing, word processing and
distributing all Registration Statements, underwriting agreements, securities
sales agreements and any other documents necessary in order to comply with this
Agreement. Nothwithstanding anything in this Agreement to the contrary, each
Holder shall pay all underwriting discounts and brokerage commissions with
respect to any Registrable Securities sold by it.

            (b)   The Company shall reimburse the Holders of the Registrable
Securities being registered in a Shelf Registration for the reasonable fees and
disbursements of not more than one counsel chosen by the Holders of a majority
in Amount of Registrable Securities to be included in such Registration
Statement ("COUNSEL TO THE HOLDERS").

6.    INDEMNIFICATION

            The Company agrees to indemnify and hold harmless (i) each Initial
Purchaser, (ii) each Holder, (iii) each Person, if any, who controls (within the
meaning of either Section 15 of the Securities Act or Section 20 of the Exchange
Act) any of the foregoing (any of the Persons referred to in this clause (iii)
being hereinafter referred to as a "controlling person"),

                                      -14-

<PAGE>

(iv) the respective officers, directors, partners, employees, representatives
and agents of the Initial Purchasers, the Holders (including predecessor
Holders) or any controlling person (any person referred to in clause (i), (ii),
(iii) or (iv) may hereinafter be referred to as an "INDEMNIFIED HOLDER"), from
and against any and all losses, claims, damages, liabilities and judgments
(including, without limitation, reasonable legal fees and other expenses
incurred in connection with any suit, action or proceeding or any claim
asserted) caused by any untrue statement or alleged untrue statement of a
material fact contained in any Registration Statement or Prospectus, or any
amendment or supplement thereto or any related preliminary prospectus, or caused
by any omission or alleged omission to state therein a material fact required to
be stated therein or necessary to make the statements therein not misleading,
except insofar as such losses, claims, damages or liabilities are caused by any
untrue statement or omission or alleged untrue statement or omission made in
reliance upon and in conformity with information relating to any Holder
furnished to the Company in writing by such Holder expressly for use in therein;
PROVIDED, HOWEVER, that the Company shall not be liable to any Indemnified
Holder under the indemnity agreement of this paragraph with respect to any
preliminary prospectus to the extent that any such loss, claim, damage,
liability, judgment or expense of such Indemnified Holder results from the fact
that such Indemnified Holder sold Registrable Securities under a Registration
Statement to a Person as to whom it shall be established that there was not sent
or given, at or prior to the written confirmation of such sale, a copy of the
Prospectus (or of the preliminary prospectus as then amended or supplemented if
the Company shall have furnished such Indemnified Holder with such amendment or
supplement thereto on a timely basis), in any case where such delivery is
required by applicable law and the loss, claim, damage, liability or expense of
such Indemnified Holder results from an untrue statement or omission of a
material fact contained in the preliminary prospectus which was corrected in the
Prospectus (or in the preliminary prospectus as then amended or supplemented if
the Company shall have furnished such Indemnified Holder with such amendment or
supplement thereto, as the case may be, on a timely basis). The Company shall
notify Indemnified Holder promptly of the institution, threat or assertion of
any claim, proceeding (including any governmental investigation) or litigation
in connection with the matters addressed by this Agreement which involves the
Company or such Indemnified Holder.

            Each Holder agrees, severally and not jointly, to indemnify and hold
harmless the Company, its directors, officers and each Person who controls the
Company within the meaning of either Section 15 of the Securities Act or Section
20 of the Exchange Act to the same extent as the foregoing indemnity from the
Company to each Holder, but only with reference to such losses, claims, damages
or liabilities which are caused by any untrue statement or omission or alleged
untrue statement or omission made in reliance upon and in conformity with
information relating to a Holder furnished to the Company in writing by such
Holder expressly for use in any Registration Statement or Prospectus, or any
amendment or supplement thereto or any related preliminary prospectus.

            If any suit, action, proceeding (including any governmental or
regulatory investigation), claim or demand shall be brought or asserted against
any Person in respect of

                                      -15-

<PAGE>

which indemnity may be sought pursuant to either of the two preceding
paragraphs, such Person (the "INDEMNIFIED PERSON") shall promptly notify the
Person or Persons against whom such indemnity may be sought (each an
"INDEMNIFYING PERSON") in writing, and such Indemnifying Person, upon request of
the Indemnified Person, shall retain counsel reasonably satisfactory to the
Indemnified Person to represent the Indemnified Person and any others entitled
to indemnification pursuant to this Section 6 that the Indemnifying Person may
designate in such proceeding and shall pay the fees and expenses of such counsel
related to such proceeding. In any such proceeding, any Indemnified Person shall
have the right to retain its own counsel, but the fees and expenses of such
counsel shall be at the expense of such Indemnified Person unless (i) such
Indemnifying Person and the Indemnified Person shall have mutually agreed to the
contrary, (ii) such Indemnifying Person has failed within a reasonable time to
retain counsel reasonably satisfactory to such Indemnified Person or (iii) the
named parties in any such proceeding (including any impleaded parties) include
an Indemnifying Person and an Indemnified Person and representation of both
parties by the same counsel would be inappropriate due to actual or potential
differing interests between them. It is understood that an Indemnifying Person
shall not, in connection with any proceeding or related proceedings in the same
jurisdiction, be liable for the fees and expenses of more than one separate firm
(in addition to any local counsel) for all Indemnified Persons, and that all
such fees and expenses shall be reimbursed as they are incurred. Any such
separate firm for the Indemnified Holders shall be designated in writing by the
Holders of the majority in Amount of Registrable Securities, and any such
separate firm for the Company, its directors, respective officers and such
control Persons of the Company shall be designated in writing by the Company.
The Indemnifying Person shall not be liable for any settlement of any proceeding
effected without its written consent, but if settled with such consent or if
there be a final judgment for the plaintiff, such Indemnifying Person agrees to
indemnify any Indemnified Person from and against any loss or liability by
reason of such settlement or judgment. No Indemnifying Person shall, without the
prior written consent of the Indemnified Person, effect any settlement of any
pending or threatened proceeding in respect of which any Indemnified Person is
or could have been a party and indemnity could have been sought hereunder by
such Indemnified Person, unless such settlement includes an unconditional
release of such Indemnified Person from all liability on claims that are the
subject matter of such proceeding.

            If the indemnification provided for in the first and second
paragraphs of this Section 6 is unavailable to an Indemnified Person or
insufficient in respect of any losses, claims, damages or liabilities referred
to therein, then each Indemnifying Person under such paragraph, in lieu of
indemnifying such Indemnified Person thereunder, shall contribute to the amount
paid or payable by such Indemnified Person as a result of such losses, claims,
damages or liabilities (i) in such proportion as is appropriate to reflect the
relative benefits received by the Indemnifying Person on the one hand and the
Indemnified Person on the other hand pursuant to the Purchase Agreement or from
the offering of the Registrable Securities pursuant to any Shelf Registration or
(ii) if the allocation provided by clause (i) above is not permitted by
applicable law, in such proportion as is appropriate to reflect not only the
relative benefits referred to in clause (i) above but also the relative fault of
the Indemnifying Person on

                                      -16-

<PAGE>

the one hand and the Indemnified Person on the other in connection with the
statements or omissions that resulted in such losses, claims, damages or
liabilities, as well as any other relevant equitable considerations. The
relative benefits received by the Company on the one hand and any Indemnified
Holder on the other shall be deemed to be in the same proportion as the total
net proceeds from the initial offering and sale of Convertible Notes (before
deducting expenses) received by the Company bear to the total net proceeds
received by such Indemnified Holder from sales of Registrable Securities giving
rise to such obligations. The relative fault of the parties shall be determined
by reference to, among other things, whether the untrue or alleged untrue
statement of a material fact or the omission or alleged omission to state a
material fact relates to information supplied by the Company or such Indemnified
Holder and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.

            Each of the Company and the Initial Purchasers agrees that it would
not be just and equitable if contribution pursuant to this Section 6 were
determined by PRO RATA allocation or by any other method of allocation that does
not take account of the equitable considerations referred to in the immediately
preceding paragraph. The amount paid or payable by an Indemnified Person as a
result of the losses, claims, damages and liabilities referred to in the
immediately preceding paragraph shall be deemed to include, subject to the
limitations set forth above, any legal or other expenses incurred by such
Indemnified Person in connection with investigating or defending any such action
or claim. Notwithstanding the provisions of this Section 6, in no event shall
any Holder be required to contribute any amount in excess of the amount by which
the net proceeds received by such Holder from the sale of the Registrable
Securities pursuant to a Shelf Registration Statement exceeds the amount of
damages which such Holder would have otherwise been required to pay by reason of
such untrue or alleged untrue statement or omission or alleged omission. No
Person guilty of fraudulent misrepresentation (within the meaning of Section
11(F) of the Securities Act) shall be entitled to contribution from any Person
who was not guilty of such fraudulent misrepresentation.

            The remedies provided for in this Section 6 are not exclusive and
shall not limit any rights or remedies that may otherwise be available to any
indemnified party at law or in equity.

            The indemnity and contribution agreements contained in this Section
6 shall remain operative and in full force and effect regardless of (i) any
termination of this Agreement, (ii) any investigation made by or on behalf of
any Holder or any Person controlling any Holder or by or on behalf of the
Company, its officers or directors or any other Person controlling any of the
Company and (iii) acceptance of and payment for any of the Registrable
Securities.

                                      -17-

<PAGE>

7.    RULES 144 AND 144A.
      ------------------

            The Company covenants that it will file the reports required to be
filed by it under the Securities Act and the Exchange Act and the rules and
regulations adopted by the SEC thereunder in a timely manner in accordance with
the requirements of the Securities Act and the Exchange Act and, for so long as
any Registrable Securities remain outstanding, if at any time the Company is not
required to file such reports, it will, upon the request of any Holder or
beneficial owner of Registrable Securities, make available such information
necessary to permit sales pursuant to Rule 144A under the Securities Act. The
Company further covenants that, for so long as any Registrable Securities remain
outstanding, it will use its reasonable best efforts to take such further action
as any Holder of Registrable Securities may reasonably request, all to the
extent required from time to time to enable such holder to sell Registrable
Securities without registration under the Securities Act within the limitation
of the exemptions provided by (a) Rule 144(k) and Rule 144A under the Securities
Act, as such rules may be amended from time to time, or (b) any similar rule or
regulation hereafter adopted by the SEC. Notwithstanding the foregoing, nothing
in this Section 7 shall be deemed to require the Company to register any of its
securities pursuant to the Exchange Act.

8.    UNDERWRITTEN REGISTRATIONS.
      --------------------------

            If any of the Registrable Securities covered by any Shelf
Registration are to be sold in an underwritten offering, the investment banker
or investment bankers and manager or managers that will manage the offering will
be selected by the Holders of the majority in Amount of Registrable Securities
to be included in such offering and will be reasonably acceptable to the
Company.

            No Holder of Registrable Securities may participate in any
underwritten registration hereunder unless such Holder (a) agrees to sell such
Holder's Registrable Securities on the basis provided in any underwriting
arrangements approved by the Persons entitled hereunder to approve such
arrangements and (b) completes and executes all questionnaires, powers of
attorney, indemnities, underwriting agreements and other documents reasonably
required under the terms of such underwriting arrangements.

9.    MISCELLANEOUS
      -------------

            (a)   NO INCONSISTENT AGREEMENTS. The Company has not, as of the
date hereof, and the Company shall not, after the date of this Agreement, enter
into any agreement with respect to any of its securities that is inconsistent
with the rights granted to the Holders of Registrable Securities in this
Agreement or otherwise conflicts with the provisions hereof. The Company has not
entered and will not enter into any agreement with respect to any of its
securities that will grant to any Person piggyback registration rights with
respect to a Registration Statement, except to the extent any existing right has
heretofore been waived.

                                      -18-

<PAGE>

            (b)   ADJUSTMENTS AFFECTING REGISTRABLE SECURITIES. The Company
shall not, directly or indirectly, take any action with respect to the
Registrable Securities as a class that would adversely affect the ability of the
Holders of Registrable Securities to include such Registrable Securities in a
registration undertaken pursuant to this Agreement.

            (c)   AMENDMENTS AND WAIVERS. The provisions of this Agreement may
not be amended, modified or supplemented, and waivers or consents to departures
from the provisions hereof may not be given, otherwise than with the prior
written consent of the Company and the Holders of not less than the majority in
Amount of Registrable Securities; PROVIDED, HOWEVER, that Section 6 and this
Section 9(c) may not be amended, modified or supplemented without the prior
written consent of the Company and each Holder (including, in the case of an
amendment, modification or supplement of Section 6, any Person who was a Holder
of Registrable Securities disposed of pursuant to any Registration Statement).
Notwithstanding the foregoing, a waiver or consent to depart from the provisions
hereof with respect to a matter that relates exclusively to the rights of
Holders of Registrable Securities whose securities are being sold pursuant to a
Registration Statement and that does not directly or indirectly affect, impair,
limit or compromise the rights of other Holders of Registrable Securities may be
given by Holders of at least a majority in Amount of the Registrable Securities
being sold by such Holders pursuant to such Registration Statement.

            (d)   NOTICES. All notices and other communications (including
without limitation any notices or other communications to the Trustee) provided
for or permitted hereunder shall be made in writing by hand-delivery, registered
first-class mail, next-day air courier or facsimile:

                  (1)   if to a Holder of the Registrable Securities, at the
            most current address of such Holder set forth on the records of the
            registrar under the Indenture, in the case of Holders of Convertible
            Notes, and the stock ledger of the Company, in the case of Holders
            of common stock of the Company.

                  (2)   if to the Initial Purchasers:

                  J.P. MORGAN SECURITIES INC.
                  CHASE SECURITIES INC.
                  LEHMAN BROTHERS INC.
                  MORGAN STANLEY & CO. INCORPORATED
                  c/o J.P. Morgan Securities Inc.
                  60 Wall Street
                  New York, New York 10260
                  Attention:        Syndicate Department

                                   -19
<PAGE>

            with copies to:

                  Cahill Gordon & Reindel
                  80 Pine Street
                  New York, New York 10005
                  Facsimile No.:  (212) 269-5420
                  Attention:        Gerald Tanenbaum, Esq.

                  (3)   if to the Company, at the addresses as follows:

                  Gilead Sciences, Inc.
                  333 Lakeside Drive
                  Foster City, California 94404
                  Attention:        Gregg H. Alton, Esq., General Counsel

            with copies to:

                  Cooley Godward LLP
                  5 Palo Alto Square
                  Palo Alto, California 94360
                  Facsimile No.:  (650) 849-7400
                  Attention:  Laura A. Berezin, Esq.

                  All such notices and communications shall be deemed to have
been duly given: when delivered by hand, if personally delivered; five Business
Days after being deposited in the mail, postage prepaid, if mailed; one Business
Day after being timely delivered to a next-day air courier; and when receipt is
acknowledged by the addressee, if sent by facsimile.

                  (e)   SUCCESSORS AND ASSIGNS. This Agreement shall inure to
the benefit of and be binding upon the successors and assigns of each of the
parties hereto, including the Holders; PROVIDED, HOWEVER, that this Agreement
shall not inure to the benefit of or be binding upon a successor or assign of a
Holder unless and except to the extent such successor or assign holds
Registrable Securities.

                  (f)   COUNTERPARTS. This Agreement may be executed in any
number of counterparts and by the parties hereto in separate counterparts, each
of which when so executed shall be deemed to be an original and all of which
taken together shall constitute one and the same agreement.

                  (g)   HEADINGS. The headings in this Agreement are for
convenience of reference only and shall not limit or otherwise affect the
meaning hereof.

                  (h)   GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW

                                      -20-

<PAGE>

YORK, AS APPLIED TO CONTRACTS MADE AND PERFORMED WHOLLY WITHIN THE STATE OF NEW
YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW. EACH OF THE PARTIES
HERETO AGREES TO SUBMIT TO THE JURISDICTION OF THE FEDERAL AND NEW YORK STATE
COURTS SITTING IN MANHATTAN, NEW YORK CITY, THE STATE OF NEW YORK, IN ANY ACTION
OR PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT.

                  (i)   SEVERABILITY. If any term, provision, covenant or
restriction of this Agreement is held by a court of competent jurisdiction to be
invalid, illegal, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions set forth herein shall remain in full force and
effect and shall in no way be affected, impaired or invalidated, and the parties
hereto shall use their best efforts to find and employ an alternative means to
achieve the same or substantially the same result as that contemplated by such
term, provision, covenant or restriction. It is hereby stipulated and declared
to be the intention of the parties that they would have executed the remaining
terms, provisions, covenants and restrictions without including any of such that
may be hereafter declared invalid, illegal, void or unenforceable.

                  (j)   SECURITIES HELD BY THE COMPANY OR ITS AFFILIATES.
Whenever the consent or approval of Holders of a specified percentage in Amount
of Registrable Securities is required hereunder, Registrable Securities held by
the Company or its affiliates (as such term is defined in Rule 405 under the
Securities Act) shall not be counted in determining whether such consent or
approval was given by the Holders of such required percentage.

                  (k)   THIRD PARTY BENEFICIARIES. Holders of Registrable
Securities are intended third party beneficiaries of this Agreement and this
Agreement may be enforced by such Persons.

                  (l)   ENTIRE AGREEMENT. This Agreement, together with the
Purchase Agreement and the Indenture, is intended by the parties as a final and
exclusive statement of the agreement and understanding of the parties hereto in
respect of the subject matter contained herein and therein and any and all prior
oral or written agreements, representations, or warranties, contracts,
understandings, correspondence, conversations and memoranda between the Initial
Purchasers on the one hand and the Company on the other, or between or among any
agents, representatives, parents, subsidiaries, affiliates, predecessors in
interest or successors in interest with respect to the subject matter hereof and
thereof are merged herein and replaced hereby.

                                      -21-

<PAGE>

            IN WITNESS WHEREOF, the parties have executed this Agreement as of
the date first written above.

                                        GILEAD SCIENCES, INC.

                                        By: /s/ John C. Martin
                                           ------------------------------
                                           Name: John C. Martin
                                           Title: President And Chief Executive
                                                  Officer

                                        J.P. MORGAN SECURITIES INC.
                                        CHASE SECURITIES INC.
                                        LEHMAN BROTHERS INC.
                                        MORGAN STANLEY & CO. INCORPORATED

                                        By: J.P. MORGAN SECURITIES INC.

                                           By: /s/ J.P. Morgan Securities Inc.
                                              --------------------------------
                                              Name:
                                              Title:

                                      -22-

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