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                                                               Exhibit 4(a)

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                                 AON CORPORATION

                                       To


                              THE BANK OF NEW YORK,
                                   as Trustee
               ---------------------------------------------------


                                    INDENTURE


                                   Dated as of

                                November 7, 2002



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


                  3 1/2 % CONVERTIBLE SENIOR DEBENTURES DUE 2012



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                                TABLE OF CONTENTS

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                                                                                              PAGE
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                                    ARTICLE 1
                                   DEFINITIONS

SECTION 1.01.  DEFINITIONS......................................................................1

                                    ARTICLE 2
             ISSUE, DESCRIPTION, EXECUTION, REGISTRATION AND EXCHANGE OF DEBENTURES

SECTION 2.01.  DESIGNATION AMOUNT AND ISSUE OF DEBENTURES.......................................8
SECTION 2.02.  FORM OF DEBENTURES...............................................................9
SECTION 2.03.  DATE AND DENOMINATION OF DEBENTURES; PAYMENTS OF INTEREST.......................10
SECTION 2.04.  EXECUTION OF DEBENTURES.........................................................11
SECTION 2.05.  EXCHANGE AND REGISTRATION OF TRANSFER OF DEBENTURES; RESTRICTIONS ON
         TRANSFER..............................................................................12
SECTION 2.06.  MUTILATED, DESTROYED, LOST OR STOLEN DEBENTURES.................................18
SECTION 2.07.  TEMPORARY DEBENTURES............................................................20
SECTION 2.08.  CANCELLATION OF DEBENTURES......................................................20
SECTION 2.09.  CUSIP NUMBERS...................................................................20

                                    ARTICLE 3
                     REDEMPTION AND REPURCHASE OF DEBENTURES

SECTION 3.01.  REDEMPTION OF DEBENTURES........................................................21
SECTION 3.02.  NOTICE OF OPTIONAL REDEMPTION; SELECTION OF DEBENTURES..........................21
SECTION 3.03.  PAYMENT OF DEBENTURES CALLED FOR REDEMPTION BY THE COMPANY......................23
SECTION 3.04.  CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION...................................24
SECTION 3.05.  REDEMPTION AT OPTION OF HOLDERS UPON A FUNDAMENTAL CHANGE.......................24
SECTION 3.06.  REPURCHASE OF DEBENTURES BY THE COMPANY AT OPTION OF THE HOLDER.................27
SECTION 3.07.  COMPANY REPURCHASE NOTICE.......................................................28
SECTION 3.08.  EFFECT OF REPURCHASE NOTICE.....................................................29
SECTION 3.09.  DEPOSIT OF PURCHASE PRICE.......................................................30
SECTION 3.10.  DEBENTURES REPURCHASED IN PART..................................................30
SECTION 3.11.  REPAYMENT TO THE COMPANY........................................................30

                                    ARTICLE 4
                               CONTINGENT INTEREST

SECTION 4.01.  CONTINGENT INTEREST.............................................................31
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SECTION 4.02.  PAYMENT OF CONTINGENT INTEREST..................................................31
SECTION 4.03.  CONTINGENT INTEREST NOTIFICATION................................................31

                                    ARTICLE 5
                       PARTICULAR COVENANTS OF THE COMPANY

SECTION 5.01.  PAYMENT OF PRINCIPAL, PREMIUM AND INTEREST......................................32
SECTION 5.02.  MAINTENANCE OF OFFICE OR AGENCY.................................................32
SECTION 5.03.  APPOINTMENTS TO FILL VACANCIES IN TRUSTEE'S OFFICE..............................32
SECTION 5.04.  PROVISIONS AS TO PAYING AGENT...................................................33
SECTION 5.05.  EXISTENCE.......................................................................34
SECTION 5.06.  MAINTENANCE OF PROPERTIES.......................................................34
SECTION 5.07.  PAYMENT OF TAXES AND OTHER CLAIMS...............................................34
SECTION 5.08.  RULE 144A INFORMATION REQUIREMENT...............................................35
SECTION 5.09.  STAY, EXTENSION AND USURY LAWS..................................................35
SECTION 5.10.  COMPLIANCE CERTIFICATE..........................................................35
SECTION 5.11.  LIQUIDATED DAMAGES NOTICE.......................................................36
SECTION 5.12.  CONTINGENT DEBT TAX TREATMENT...................................................36
SECTION 5.13.  CALCULATION OF ORIGINAL ISSUE DISCOUNT..........................................37

                                    ARTICLE 6
               DEBENTUREHOLDERS' LISTS AND REPORTS BY THE COMPANY AND THE TRUSTEE

SECTION 6.01.  DEBENTUREHOLDERS' LISTS.........................................................37
SECTION 6.02.  PRESERVATION AND DISCLOSURE OF LISTS............................................38
SECTION 6.03.  REPORTS BY TRUSTEE..............................................................38
SECTION 6.04.  REPORTS BY COMPANY..............................................................38

                                    ARTICLE 7
               REMEDIES OF THE TRUSTEE AND DEBENTUREHOLDERS ON AN EVENT OF DEFAULT

SECTION 7.01.  EVENTS OF DEFAULT...............................................................39
SECTION 7.02.  PAYMENTS OF DEBENTURES ON DEFAULT; SUIT THEREFOR................................41
SECTION 7.03.  APPLICATION OF MONIES COLLECTED BY TRUSTEE......................................42
SECTION 7.04.  PROCEEDINGS BY DEBENTUREHOLDER..................................................43
SECTION 7.05.  PROCEEDINGS BY TRUSTEE..........................................................44
SECTION 7.06.  REMEDIES CUMULATIVE AND CONTINUING..............................................44
SECTION 7.07.  DIRECTION OF PROCEEDINGS AND WAIVER OF DEFAULTS BY MAJORITY OF
         DEBENTUREHOLDERS......................................................................45
SECTION 7.08.  NOTICE OF DEFAULTS..............................................................45
SECTION 7.09.  UNDERTAKING TO PAY COSTS........................................................45

                                    ARTICLE 8
                                   THE TRUSTEE

SECTION 8.01.  DUTIES AND RESPONSIBILITIES OF TRUSTEE..........................................46


                                       ii
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SECTION 8.02.  RELIANCE ON DOCUMENTS, OPINIONS, ETC............................................47
SECTION 8.03.  NO RESPONSIBILITY FOR RECITALS, ETC.............................................49
SECTION 8.04.  TRUSTEE, PAYING AGENTS, CONVERSION AGENTS OR REGISTRAR MAY OWN DEBENTURES.......49
SECTION 8.05.  MONIES TO BE HELD IN TRUST......................................................49
SECTION 8.06.  COMPENSATION AND EXPENSES OF TRUSTEE............................................49
SECTION 8.07.  OFFICERS' CERTIFICATE AS EVIDENCE...............................................50
SECTION 8.08.  CONFLICTING INTERESTS OF TRUSTEE................................................50
SECTION 8.09.  ELIGIBILITY OF TRUSTEE..........................................................50
SECTION 8.10.  RESIGNATION OR REMOVAL OF TRUSTEE...............................................51
SECTION 8.11.  ACCEPTANCE BY SUCCESSOR TRUSTEE.................................................52
SECTION 8.12.  SUCCESSION BY MERGER............................................................53
SECTION 8.13.  PREFERENTIAL COLLECTION OF CLAIMS...............................................53

                                    ARTICLE 9
                              THE DEBENTUREHOLDERS

SECTION 9.01.  ACTION BY DEBENTUREHOLDERS......................................................53
SECTION 9.02.  PROOF OF EXECUTION BY DEBENTUREHOLDERS..........................................54
SECTION 9.03.  WHO ARE DEEMED ABSOLUTE OWNERS..................................................54
SECTION 9.04.  COMPANY-OWNED DEBENTURES DISREGARDED............................................54
SECTION 9.05.  REVOCATION OF CONSENTS, FUTURE HOLDERS BOUND....................................55

                                   ARTICLE 10
                          MEETINGS OF DEBENTUREHOLDERS

SECTION 10.01.  PURPOSE OF MEETINGS............................................................55
SECTION 10.02.  CALL OF MEETINGS BY TRUSTEE....................................................56
SECTION 10.03.  CALL OF MEETINGS BY COMPANY OR DEBENTUREHOLDERS................................56
SECTION 10.04.  QUALIFICATIONS FOR VOTING......................................................56
SECTION 10.05.  REGULATIONS....................................................................57
SECTION 10.06.  VOTING.........................................................................57
SECTION 10.07.  NO DELAY OF RIGHTS BY MEETING..................................................58

                                   ARTICLE 11
                             SUPPLEMENTAL INDENTURES

SECTION 11.01.  SUPPLEMENTAL INDENTURES WITHOUT CONSENT OF DEBENTUREHOLDERS....................58
SECTION 11.02.  SUPPLEMENTAL INDENTURE WITH CONSENT OF DEBENTUREHOLDERS........................60
SECTION 11.03.  EFFECT OF SUPPLEMENTAL INDENTURE...............................................61
SECTION 11.04.   NOTATION ON DEBENTURES........................................................61
SECTION 11.05.  EVIDENCE OF COMPLIANCE OF SUPPLEMENTAL INDENTURE TO BE FURNISHED TO
         TRUSTEE...............................................................................61


                                      iii
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                                   ARTICLE 12
                  CONSOLIDATION, MERGER, SALE, CONVEYANCE AND LEASE

SECTION 12.01.  COMPANY MAY CONSOLIDATE ON CERTAIN TERMS.......................................61
SECTION 12.02.  SUCCESSOR TO BE SUBSTITUTED....................................................62
SECTION 12.03.  OPINION OF COUNSEL TO BE GIVEN TRUSTEE.........................................63

                                   ARTICLE 13
                     SATISFACTION AND DISCHARGE OF INDENTURE

SECTION 13.01.  DISCHARGE OF INDENTURE.........................................................63
SECTION 13.02.  DEPOSITED MONIES TO BE HELD IN TRUST BY TRUSTEE................................64
SECTION 13.03.  PAYING AGENT TO REPAY MONIES HELD..............................................64
SECTION 13.04.  RETURN OF UNCLAIMED MONIES.....................................................64
SECTION 13.05.  REINSTATEMENT..................................................................64

                                   ARTICLE 14
            IMMUNITY OF INCORPORATORS, STOCKHOLDERS, OFFICERS AND DIRECTORS

SECTION 14.01.  INDENTURE AND DEBENTURES SOLELY CORPORATE OBLIGATIONS..........................65

                                   ARTICLE 15
                            CONVERSION OF DEBENTURES

SECTION 15.01.  RIGHT TO CONVERT...............................................................65
SECTION 15.02.  EXERCISE OF CONVERSION PRIVILEGE; ISSUANCE OF COMMON STOCK ON CONVERSION;
         NO ADJUSTMENT FOR INTEREST OR DIVIDENDS...............................................68
SECTION 15.03.  CASH PAYMENTS IN LIEU OF FRACTIONAL SHARES.....................................70
SECTION 15.04.  CONVERSION RATE................................................................70
SECTION 15.05.  ADJUSTMENT OF CONVERSION RATE..................................................70
SECTION 15.06.  EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR SALE......................80
SECTION 15.07.  TAXES ON SHARES ISSUED.........................................................81
SECTION 15.08.  RESERVATION OF SHARES, SHARES TO BE FULLY PAID; COMPLIANCE WITH
         GOVERNMENTAL REQUIREMENTS; LISTING OF COMMON STOCK....................................81
SECTION 15.09.  RESPONSIBILITY OF TRUSTEE......................................................82
SECTION 15.10.  NOTICE TO HOLDERS PRIOR TO CERTAIN ACTIONS.....................................83
SECTION 15.11.  FUTURE STOCKHOLDER RIGHTS PLANS................................................83

                                   ARTICLE 16
                            MISCELLANEOUS PROVISIONS

SECTION 16.01.  PROVISIONS BINDING ON COMPANY'S SUCCESSORS.....................................84
SECTION 16.02.  OFFICIAL ACTS BY SUCCESSOR CORPORATION.........................................84
SECTION 16.03.  ADDRESSES FOR NOTICES, ETC.....................................................84
SECTION 16.04.  GOVERNING LAW..................................................................85
SECTION 16.05.  EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT, CERTIFICATES TO TRUSTEE......85

                                      iv
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SECTION 16.06.  LEGAL HOLIDAYS.................................................................85
SECTION 16.07.  TRUST INDENTURE ACT............................................................85
SECTION 16.08.  NO SECURITY INTEREST CREATED...................................................86
SECTION 16.09.  BENEFITS OF INDENTURE..........................................................86
SECTION 16.10.  TABLE OF CONTENTS, HEADINGS, ETC...............................................86
SECTION 16.11.  AUTHENTICATING AGENT...........................................................86
SECTION 16.12.  EXECUTION IN COUNTERPARTS......................................................87
SECTION 16.13.  SEVERABILITY...................................................................87
Annex 1                                                                                        93
Exhibit A     Form of Debenture                                                               A-1
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                                       v
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                                    INDENTURE

         INDENTURE dated as of November 7, 2002 between Aon Corporation, a
Delaware corporation (hereinafter called the "COMPANY"), having its principal
office at 200 East Randolph Street, Chicago, Illinois 60601, and The Bank of New
York, a New York banking corporation, as trustee hereunder (hereinafter called
the "TRUSTEE").

                                   WITNESSETH:

         WHEREAS, for its lawful corporate purposes, the Company has duly
authorized the issue of its 3 1/2 % Convertible Senior Debentures Due 2012
(hereinafter called the "DEBENTURES"), in an aggregate principal amount not to
exceed $300,000,000 and, to provide the terms and conditions upon which the
Debentures are to be authenticated, issued and delivered, the Company has duly
authorized the execution and delivery of this Indenture; and

         WHEREAS, the Debentures, the certificate of authentication to be borne
by the Debentures, a form of assignment, a form of option to elect redemption
upon a fundamental change, a form of repurchase notice and a form of conversion
notice to be borne by the Debentures are to be substantially in the forms
hereinafter provided for; and

         WHEREAS, all acts and things necessary to make the Debentures, when
executed by the Company and authenticated and delivered by the Trustee or a duly
authorized authenticating agent, as in this Indenture provided, the valid,
binding and legal obligations of the Company, and to constitute this Indenture a
valid agreement according to its terms, have been done and performed, and the
execution of this Indenture and the issue hereunder of the Debentures have in
all respects been duly authorized,

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         That in order to declare the terms and conditions upon which the
Debentures are, and are to be, authenticated, issued and delivered, and in
consideration of the premises and of the purchase and acceptance of the
Debentures by the holders thereof, the Company covenants and agrees with the
Trustee for the equal and proportionate benefit of the respective holders from
time to time of the Debentures (except as otherwise provided below), as follows:


                                    ARTICLE 1
                                   DEFINITIONS

         Section 1.01. DEFINITIONS. The terms defined in this Section 1.01
(except as herein otherwise expressly provided or unless the context otherwise
requires) for all purposes of this Indenture and of any indenture supplemental
hereto shall
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have the respective meanings specified in this Section 1.01. All other terms
used in this Indenture that are defined in the Trust Indenture Act or which are
by reference therein defined in the Securities Act (except as herein otherwise
expressly provided or unless the context otherwise requires) shall have the
meanings assigned to such terms in the Trust Indenture Act and in the Securities
Act as in force at the date of the execution of this Indenture. The words
"HEREIN", "HEREOF", "HEREUNDER" and words of similar import refer to this
Indenture as a whole and not to any particular Article, Section or other
Subdivision. The terms defined in this Article include the plural as well as the
singular.

         "ACCEPTED PURCHASED SHARES" has the meaning specified in Section
15.05(g).

         "ADJUSTMENT EVENT" has the meaning specified in Section 15.05(l).

         "AGENT MEMBERS" has the meaning specified in Section 2.05(a).

         "AFFILIATE" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"CONTROL", when used with respect to any specified Person means the power to
direct or cause the direction of the management and policies of such Person,
directly or indirectly, whether through the ownership of voting securities, by
contract or otherwise, and the terms "CONTROLLING" and "CONTROLLED" have
meanings correlative to the foregoing.

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

         "BUSINESS DAY" means any day except a Saturday, Sunday or legal holiday
on which banking institutions in The City of New York are authorized or
obligated by law, regulation or executive order to close.

         "CLOSING SALE PRICE" of the shares of Common Stock on any date means
the closing sale price per share (or, if no closing sale price is reported, the
average of the closing bid and ask prices or, if more than one in either case,
the average of the average closing bid and the average closing ask prices) on
such date as reported in composite transactions for the principal United States
securities exchange on which shares of Common Stock are traded or, if the shares
of Common Stock are not listed on a United States national or regional
securities exchange, as reported by the Nasdaq or by the National Quotation
Bureau Incorporated. In the absence of such quotations, the Company shall be
entitled to determine the Closing Sale Price on the basis it considers
appropriate. The Closing Sale Price shall be determined without reference to
extended or after hours trading.


                                       2
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         "COMMISSION" means the Securities and Exchange Commission, as from time
to time constituted, created under the Exchange Act, or, if at any time after
the execution of this Indenture such Commission is not existing and performing
the duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

         "COMMON STOCK" means any stock of any class of the Company which has no
preference in respect of dividends or of amounts payable in the event of any
voluntary or involuntary liquidation, dissolution or winding up of the Company
and which is not subject to redemption by the Company. Subject to the provisions
of Section 15.06, however, shares issuable on conversion of Debentures shall
include only shares of the class designated as common stock of the Company at
the date of this Indenture (namely, the Common Stock, par value $1.00) or shares
of any class or classes resulting from any reclassification or reclassifications
thereof and which have no preference in respect of dividends or of amounts
payable in the event of any voluntary or involuntary liquidation, dissolution or
winding up of the Company and which are not subject to redemption by the
Company; PROVIDED that if at any time there shall be more than one such
resulting class, the shares of each such class then so issuable on conversion
shall be substantially in the proportion which the total number of shares of
such class resulting from all such reclassifications bears to the total number
of shares of all such classes resulting from all such reclassifications.

         "COMPANY" means the corporation named as the "COMPANY" in the first
paragraph of this Indenture, and, subject to the provisions of Article 12 and
Section 15.06, shall include its successors and assigns.

         "COMPANY REPURCHASE NOTICE" has the meaning specified in Section
3.07(b).

         "COMPANY REPURCHASE NOTICE DATE" has the meaning specified in Section
3.07(b).

         "CONTINGENT INTEREST" means interest that accrues and is payable as
provided in Article 4.

         "CONVERSION PRICE" as of any day will equal $1,000 divided by the
Conversion Rate as of such date.

         "CONVERSION RATE" has the meaning specified in Section 15.04.

         "CORPORATE TRUST OFFICE" or other similar term, means the designated
office of the Trustee at which at any particular time its corporate trust
business as it relates to this Indenture shall be administered, which office is,
at the date as of which this Indenture is dated, located at c/o BNY Midwest
Trust Company, 2 North LaSalle Street, Suite 1020, Chicago, IL 60602


                                       3
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         "CURRENT MARKET PRICE" has the meaning specified in Section 15.05(h).

         "CUSTODIAN" means The Bank of New York, as custodian with respect to
the Debentures in global form, or any successor entity thereto.

         "DEBENTURE" or "DEBENTURES" means any Debenture or Debentures, as the
case may be, authenticated and delivered under this Indenture, including any
Global Debenture.

         "DEBENTURE REGISTER" has the meaning specified in Section 2.05.

         "DEBENTURE REGISTRAR" has the meaning specified in Section 2.05.

         "DEBENTUREHOLDER" or "HOLDER" as applied to any Debenture, or other
similar terms (but excluding the term "BENEFICIAL HOLDER"), means any Person in
whose name at the time a particular Debenture is registered on the Debenture
registrar's books.

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

         "DEFAULTED INTEREST" has the meaning specified in Section 2.03.

         "DEPOSITARY" means, the clearing agency registered under the Exchange
Act that is designated to act as the Depositary for the Global Debentures. The
Depository Trust Company shall be the initial Depositary, until a successor
shall have been appointed and become such pursuant to the applicable provisions
of this Indenture, and thereafter, "DEPOSITARY" shall mean or include such
successor.

         "DETERMINATION DATE" has the meaning specified in Section 15.05(l).

         "EVENT OF DEFAULT" means any event specified in Section 7.01 as an
Event of Default.

         "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended,
and the rules and regulations promulgated thereunder, as in effect from time to
time.

         "EX-DIVIDEND TIME" has the meaning specified in Section 15.01(b).

         "EXPIRATION TIME" has the meaning specified in Section 15.05(f).

         "FAIR MARKET VALUE" has the meaning specified in Section 15.05(h).

         "FUNDAMENTAL CHANGE" means the occurrence of any transaction or event
in connection with which all or substantially all of the Common Stock shall be
exchanged for, converted into, acquired for or constitutes solely the right to
receive consideration (whether by means of an exchange offer, liquidation,
tender


                                       4
<Page>

offer, consolidation, merger, combination, reclassification, recapitalization or
otherwise) which is not all or substantially all common stock that is (or, upon
consummation of or immediately following such transaction or event, which will
be) listed on a United States national securities exchange or approved (or, upon
consummation of or immediately following such transaction or event, which will
be approved) for quotation on the Nasdaq National Market or any similar United
States system of automated dissemination of quotations of securities prices.

         "FUNDAMENTAL CHANGE NOTICE" has the meaning specified in Section
3.05(b).

         "FUNDAMENTAL CHANGE EXPIRATION TIME" has the meaning specified in
Section 3.05(b).

         "FUNDAMENTAL CHANGE REDEMPTION DATE" has the meaning specified in
Section 3.05(a).

         "GLOBAL DEBENTURE" has the meaning specified in Section 2.02.

         "INDENTURE" means this instrument as originally executed or, if amended
or supplemented as herein provided, as so amended or supplemented.

         "INITIAL PURCHASER" means Morgan Stanley & Co. Incorporated.

         "INTEREST" means, when used with reference to the Debentures, any
interest payable under the terms of the Debentures, including contingent
interest, if any, and Liquidated Damages, if any, payable under the terms of the
Registration Rights Agreement.

         "LIQUIDATED DAMAGES" has the meaning specified for "LIQUIDATED DAMAGES
AMOUNT" in Section 2(e) of the Registration Rights Agreement.

         "LIQUIDATED DAMAGES NOTICE" has the meaning specified in Section 5.11.

         "MARKET PRICE" has the meaning specified in Section 3.07(a).

         "NON-ELECTING SHARE" has the meaning specified in Section 15.06.

         "NOTICE DATE" means the date of mailing of the notice of redemption
pursuant to Section 3.02.

         "OFFER EXPIRATION TIME" has the meaning specified in Section 15.05(g).

         "OFFICERS' CERTIFICATE", when used with respect to the Company, means a
certificate signed by the Chairman of the Board, the Chief Executive Officer,
the President or any Vice President (whether or not designated by a number or
numbers or word or words added before or after the title "VICE PRESIDENT"), the
Treasurer or any Assistant Treasurer, or the Secretary of the Company.


                                       5
<Page>

         "OPINION OF COUNSEL" means an opinion in writing signed by legal
counsel, who may be an employee of or counsel to the Company, or other counsel
reasonably acceptable to the Trustee.

         "OPTIONAL REDEMPTION" has the meaning specified in Section 3.02.

         "OUTSTANDING", when used with reference to Debentures and subject to
the provisions of Section 9.04, means, as of any particular time, all Debentures
authenticated and delivered by the Trustee under this Indenture, except:

         (a) Debentures theretofore canceled by the Trustee or delivered to the
Trustee for cancellation;

         (b) Debentures, or portions thereof, (i) for the redemption of which
monies in the necessary amount shall have been deposited in trust with the
Trustee or with any paying agent (other than the Company) or (ii) which shall
have been otherwise defeased in accordance with Article 13;

         (c) Debentures in lieu of which, or in substitution for which, other
Debentures shall have been authenticated and delivered pursuant to the terms of
Section 2.06; and

         (d) Debentures converted into Common Stock pursuant to Article 15 and
Debentures deemed not outstanding pursuant to Article 3.

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

         "PORTAL MARKET" means The Portal Market operated by the National
Association of Securities Dealers, Inc. or any successor thereto.

         "PREDECESSOR DEBENTURE" of any particular Debenture means every
previous Debenture evidencing all or a portion of the same debt as that
evidenced by such particular Debenture, and, for the purposes of this
definition, any Debenture authenticated and delivered under Section 2.06 in lieu
of a lost, destroyed or stolen Debenture shall be deemed to evidence the same
debt as the lost, destroyed or stolen Debenture that it replaces.

         "PREMIUM" means any premium payable under the terms of the Debentures.

         "PRINCIPAL VALUE CONVERSION" has the meaning specified in Section
15.01.

         "PURCHASED SHARES" has the meaning specified in Section 15.05(f).


                                       6
<Page>

         "QIB" means a "QUALIFIED INSTITUTIONAL BUYER" as defined in Rule 144A.

         "RECORD DATE" has the meaning specified in Section 15.05(h).

         "REGISTRATION RIGHTS AGREEMENT" means the Registration Rights
Agreement, dated as of November 7, 2002, between the Company and the Initial
Purchaser, as amended from time to time in accordance with its terms.

         "REGULAR CASH DIVIDEND" has the meaning specified in Section 4.01.

         "REPURCHASE DATE" has the meaning specified in Section 3.06.

         "REPURCHASE NOTICE" has the meaning specified in Section 3.06.

         "RESPONSIBLE OFFICER" shall mean, when used with respect to the
Trustee, any officer within the corporate trust department of the Trustee,
including any vice president, assistant vice president, assistant secretary,
assistant treasurer, trust officer or any other officer of the Trustee who
customarily performs functions similar to those performed by the persons who at
the time shall be such officers, respectively, or to whom any corporate trust
matter is referred because of such person's knowledge of any familiarity with
the particular subject and who shall have direct responsibility for the
administration of this Indenture.

         "RESTRICTED SECURITIES" has the meaning specified in Section 2.05(c).

         "RIGHTS" has the meaning specified in Section 15.11.

          "RULE 144A" means Rule 144A as promulgated under the Securities Act.

         "SECURITIES" has the meaning specified in Section 15.05(d).

         "SECURITIES ACT" means the Securities Act of 1933, as amended, and the
rules and regulations promulgated thereunder, as in effect from time to time.

         "SIGNIFICANT SUBSIDIARY" means, as of any date of determination, a
Subsidiary of the Company that would constitute a "SIGNIFICANT SUBSIDIARY" as
such term is defined under Rule 1-02(w) of Regulation S-X of the Commission as
in effect on the date of this Indenture.

         "SUBSIDIARY" means, with respect to any Person, (i) any corporation,
association or other business entity of which more than 50% of the total voting
power of shares of capital stock or other equity interest entitled (without
regard to the occurrence of any contingency) to vote in the election of
directors, managers or trustees thereof is at the time owned or controlled,
directly or indirectly, by such Person or one or more of the other subsidiaries
of that Person (or a combination thereof) and (ii) any partnership (a) the sole
general partner or managing general partner of which is such Person or a
subsidiary of such Person


                                       7
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or (b) the only general partners of which are such Person or of one or more
subsidiaries of such Person (or any combination thereof).

         "TAX ORIGINAL ISSUE DISCOUNT" means the amount of ordinary interest
income on a Debenture that must be accrued as original issue discount for United
States Federal income tax purposes pursuant to U.S. Treasury Regulation section
1.1275-4.

         "TRADING DAY" has the meaning specified in Section 15.05(h).

         "TRADING PRICE" means, on any date, the average of the secondary market
bid quotations for the Debentures obtained by the Trustee for $10,000,000
principal amount of Debentures at approximately 3:30 p.m., New York City time,
on such date from three independent nationally recognized securities dealers
selected by the Company; PROVIDED that if at least three such bids cannot
reasonably be obtained by the Trustee, but two bids are obtained, then the
average of the two bids shall be used, and if only one such bid can reasonably
be obtained by the Trustee, one bid shall be used; and provided further that if
the Trustee cannot reasonably obtain at least one bid for $10,000,000 principal
amount of Debentures from a nationally recognized securities dealer or in the
Company's reasonable judgment, the bid quotations are not indicative of the
secondary market value of the Debentures, then the Trading Price per $1,000
principal amount of Debentures shall be deemed to be less than 95% of the
product of (a) the number of shares of Common Stock issuable upon conversion of
$1,000 principal amount of Debentures and (b) the Closing Sale Price on such
date.

         "TRIGGER EVENT" has the meaning specified in Section 15.05(d).

         "TRUST INDENTURE ACT" means the Trust Indenture Act of 1939, as
amended, as it was in force at the date of this Indenture, except as provided in
Sections 11.03 and 15.06; PROVIDED that if the Trust Indenture Act of 1939 is
amended after the date hereof, the term "TRUST INDENTURE ACT" shall mean, to the
extent required by such amendment, the Trust Indenture Act of 1939 as so
amended.

         "TRUSTEE" means The Bank of New York and its successors and any
corporation resulting from or surviving any consolidation or merger to which it
or its successors may be a party and any successor trustee at the time serving
as successor trustee hereunder.



                                    ARTICLE 2
     ISSUE, DESCRIPTION, EXECUTION, REGISTRATION AND EXCHANGE OF DEBENTURES

         Section 2.01. DESIGNATION AMOUNT AND ISSUE OF DEBENTURES. The
Debentures shall be designated as "3 1/2 % CONVERTIBLE SENIOR DEBENTURES DUE


                                       8
<Page>

2012". Debentures not to exceed the aggregate principal amount of $300,000,000
(except pursuant to Sections 2.05, 2.06, 3.03, 3.05 and 15.02 hereof) upon the
execution of this Indenture, or from time to time thereafter, may be executed by
the Company and delivered to the Trustee for authentication, and the Trustee
shall thereupon authenticate and deliver said Debentures to or upon the written
order of the Company, signed by its Chairman of the Board, Chief Executive
Officer, President or any Vice President (whether or not designated by a number
or numbers or word or words added before or after the title "VICE PRESIDENT"),
the Treasurer or any Assistant Treasurer or the Secretary, without any further
action by the Company hereunder.

         Section 2.02. FORM OF DEBENTURES. The Debentures and the Trustee's
certificate of authentication to be borne by such Debentures shall be
substantially in the form set forth in Exhibit A. The terms and provisions
contained in the form of Debenture attached as Exhibit A hereto shall
constitute, and are hereby expressly made, a part of this Indenture and, to the
extent applicable, the Company and the Trustee, by their execution and delivery
of this Indenture, expressly agree to such terms and provisions and to be bound
thereby.

         Any of the Debentures may have such letters, numbers or other marks of
identification and such notations, legends, endorsements or changes as the
officers executing the same may approve (execution thereof to be conclusive
evidence of such approval) and as are not inconsistent with the provisions of
this Indenture, or as may be required by the Custodian, the Depositary or by the
National Association of Securities Dealers, Inc. in order for the Debentures to
be tradable on The Portal Market or as may be required for the Debentures to be
tradable on any other market developed for trading of securities pursuant to
Rule 144A or as may be required to comply with any applicable law or with any
rule or regulation made pursuant thereto or with any rule or regulation of any
securities exchange or automated quotation system on which the Debentures may be
listed, or to conform to usage, or to indicate any special limitations or
restrictions to which any particular Debentures are subject.

         So long as the Debentures are eligible for book-entry settlement with
the Depositary, or unless otherwise required by law, or otherwise contemplated
by Section 2.05(a), all of the Debentures will be represented by one or more
Debentures in global form registered in the name of the Depositary or the
nominee of the Depositary (a "GLOBAL DEBENTURE"). The transfer and exchange of
beneficial interests in any such Global Debenture shall be effected through the
Depositary in accordance with this Indenture and the applicable procedures of
the Depositary. Except as provided in Section 2.05(a), beneficial owners of a
Global Debenture shall not be entitled to have certificates registered in their
names, will not receive or be entitled to receive physical delivery of
certificates in definitive form and will not be considered holders of such
Global Debenture.

         Any Global Debenture shall represent such of the outstanding Debentures
as shall be specified therein and shall provide that it shall represent the
aggregate


                                       9
<Page>

amount of outstanding Debentures from time to time endorsed thereon and that the
aggregate amount of outstanding Debentures represented thereby may from time to
time be increased or reduced to reflect redemptions, repurchases, conversions,
transfers or exchanges permitted hereby. Any endorsement of a Global Debenture
to reflect the amount of any increase or decrease in the amount of outstanding
Debentures represented thereby shall be made by the Trustee or the Custodian, at
the direction of the Trustee, in such manner and upon instructions given by the
holder of such Debentures in accordance with this Indenture. Payment of
principal of and interest and premium, if any, on any Global Debenture shall be
made to the holder of such Debenture.

         Section 2.03. DATE AND DENOMINATION OF DEBENTURES; PAYMENTS OF
INTEREST. The Debentures shall be issuable in registered form without coupons in
denominations of $1,000 principal amount and integral multiples thereof. Each
Debenture shall be dated the date of its authentication and shall bear interest
from the date specified on the face of the form of Debenture attached as Exhibit
A hereto. Interest on the Debentures shall be computed on the basis of a 360-day
year comprised of twelve 30-day months.

         The Person in whose name any Debenture (or its Predecessor Debenture)
is registered on the Debenture register at the close of business on any record
date with respect to any interest payment date shall be entitled to receive the
interest payable on such interest payment date, except that the interest payable
upon redemption or repurchase will be payable to the Person to whom principal is
payable pursuant to such redemption or repurchase (unless the redemption date or
the Repurchase Date, as the case may be, is an interest payment date, in which
case the semi-annual payment of interest becoming due on such date shall be
payable to the holders of such Debentures registered as such on the applicable
record date). Notwithstanding the foregoing, if any Debenture (or portion
thereof) is converted into Common Stock during the period after a record date
for the payment of interest to, but excluding, the next succeeding interest
payment date and such Debenture (or portion thereof) has been called or tendered
for redemption on a redemption date which occurs during such period, the Company
shall not be required to pay interest on such interest payment date in respect
of any such Debenture (or portion thereof). Interest shall be payable at the
office of the Company maintained by the Company for such purposes in the Borough
of Manhattan, City of New York, which shall initially be an office or agency of
the Trustee. The Company shall pay interest (i) on any Debentures in
certificated form by check mailed to the address of the Person entitled thereto
as it appears in the Debenture register or (ii) on any Global Debenture by wire
transfer of immediately available funds to the account of the Depositary or its
nominee. The term "RECORD DATE" with respect to any interest payment date shall
mean the May 1 or November 1 preceding the applicable May 15 or November 15
interest payment date, respectively.

         Any interest on any Debenture which is payable, but is not punctually
paid or duly provided for, on any May 15 or November 15 (herein called
"DEFAULTED


                                       10
<Page>

INTEREST") shall forthwith cease to be payable to the Debentureholder on the
relevant record date by virtue of his having been such Debentureholder, and such
Defaulted Interest shall be paid by the Company, at its election in each case,
as provided in clause (1) or (2) below:

         (1) The Company may elect to make payment of any Defaulted Interest to
the Persons in whose names the Debentures (or their respective Predecessor
Debentures) are registered at the close of business on a special record date for
the payment of such Defaulted Interest, which shall be fixed in the following
manner. The Company shall notify the Trustee in writing of the amount of
Defaulted Interest proposed to be paid on each Debenture and the date of the
proposed payment (which shall be not less than twenty-five (25) days after the
receipt by the Trustee of such notice, unless the Trustee shall consent to an
earlier date), and at the same time the Company shall deposit with the Trustee
an amount of money equal to the aggregate amount to be paid in respect of such
Defaulted Interest or shall make arrangements satisfactory to the Trustee for
such deposit on or prior to the date of the proposed payment, such money when
deposited to be held in trust for the benefit of the Persons entitled to such
Defaulted Interest as in this clause provided. Thereupon the Trustee shall fix a
special record date for the payment of such Defaulted Interest which shall be
not more than fifteen (15) days and not less than ten (10) days prior to the
date of the proposed payment, and not less than ten (10) days after the receipt
by the Trustee of the notice of the proposed payment. The Trustee shall promptly
notify the Company of such special record date and, in the name and at the
expense of the Company, shall cause notice of the proposed payment of such
Defaulted Interest and the special record date therefor to be mailed,
first-class postage prepaid, to each holder at his address as it appears in the
Debenture register, not less than ten (10) days prior to such special record
date. Notice of the proposed payment of such Defaulted Interest and the special
record date therefor having been so mailed, such Defaulted Interest shall be
paid to the Persons in whose names the Debentures (or their respective
Predecessor Debentures) are registered at the close of business on such special
record date and shall no longer be payable pursuant to the following clause (2)
of this Section 2.03.

         (2) The Company may make payment of any Defaulted Interest in any other
lawful manner not inconsistent with the requirements of any securities exchange
or automated quotation system on which the Debentures may be listed or
designated for issuance, and upon such notice as may be required by such
exchange or automated quotation system, if, after notice given by the Company to
the Trustee of the proposed payment pursuant to this clause, such manner of
payment shall be deemed practicable by the Trustee.

         Section 2.04. EXECUTION OF DEBENTURES. The Debentures shall be signed
in the name and on behalf of the Company by the manual or facsimile signature of
its Chairman of the Board, Chief Executive Officer, President or any Vice
President (whether or not designated by a number or numbers or word or words
added before or after the title "VICE PRESIDENT") and attested by the manual or


                                       11
<Page>

facsimile signature of its Secretary or any of its Assistant Secretaries or its
Treasurer or any of its Assistant Treasurers (which may be printed, engraved or
otherwise reproduced thereon, by facsimile or otherwise). Only such Debentures
as shall bear thereon a certificate of authentication substantially in the form
set forth on the form of Debenture attached as Exhibit A hereto, manually
executed by the Trustee (or an authenticating agent appointed by the Trustee as
provided by Section 16.11), shall be entitled to the benefits of this Indenture
or be valid or obligatory for any purpose. Such certificate by the Trustee (or
such an authenticating agent) upon any Debenture executed by the Company shall
be conclusive evidence that the Debenture so authenticated has been duly
authenticated and delivered hereunder and that the holder is entitled to the
benefits of this Indenture.

         In case any officer of the Company who shall have signed any of the
Debentures shall cease to be such officer before the Debentures so signed shall
have been authenticated and delivered by the Trustee, or disposed of by the
Company, such Debentures nevertheless may be authenticated and delivered or
disposed of as though the person who signed such Debentures had not ceased to be
such officer of the Company, and any Debenture may be signed on behalf of the
Company by such persons as, at the actual date of the execution of such
Debenture, shall be the proper officers of the Company, although at the date of
the execution of this Indenture any such person was not such an officer.

         Section 2.05. EXCHANGE AND REGISTRATION OF TRANSFER OF DEBENTURES;
RESTRICTIONS ON TRANSFER. (a) The Company shall cause to be kept at the
Corporate Trust Office a register (the register maintained in such office and in
any other office or agency of the Company designated pursuant to Section 5.02
being herein sometimes collectively referred to as the "DEBENTURE REGISTER") in
which, subject to such reasonable regulations as it may prescribe, the Company
shall provide for the registration of Debentures and of transfers of Debentures.
The Debenture register shall be in written form or in any form capable of being
converted into written form within a reasonably prompt period of time. The
Trustee is hereby appointed "DEBENTURE REGISTRAR" for the purpose of registering
Debentures and transfers of Debentures as herein provided. The Company may
appoint one or more co-registrars in accordance with Section 5.02.

         Upon surrender for registration of transfer of any Debenture to the
Debenture registrar or any co-registrar, and satisfaction of the requirements
for such transfer set forth in this Section 2.05, the Company shall execute, and
the Trustee shall authenticate and deliver, in the name of the designated
transferee or transferees, one or more new Debentures of any authorized
denominations and of a like aggregate principal amount and bearing such
restrictive legends as may be required by this Indenture.

         Debentures may be exchanged for other Debentures of any authorized
denominations and of a like aggregate principal amount, upon surrender of the
Debentures to be exchanged at any such office or agency maintained by the


                                       12
<Page>

Company pursuant to Section 5.02. Whenever any Debentures are so surrendered for
exchange, the Company shall execute, and the Trustee shall authenticate and
deliver, the Debentures which the Debentureholder making the exchange is
entitled to receive bearing registration numbers not contemporaneously
outstanding.

         All Debentures issued upon any registration of transfer or exchange of
Debentures shall be the valid obligations of the Company, evidencing the same
debt, and entitled to the same benefits under this Indenture, as the Debentures
surrendered upon such registration of transfer or exchange.

         All Debentures presented or surrendered for registration of transfer or
for exchange, redemption, repurchase or conversion shall (if so required by the
Company or the Debenture registrar) be duly endorsed, or be accompanied by a
written instrument or instruments of transfer in form satisfactory to the
Company, and the Debentures shall be duly executed by the Debentureholder
thereof or his attorney duly authorized in writing.

         No service charge shall be made to any holder for any registration of,
transfer or exchange of Debentures, but the Company may require payment by the
holder of a sum sufficient to cover any tax, assessment or other governmental
charge that may be imposed in connection with any registration of transfer or
exchange of Debentures.

         Neither the Company nor the Trustee nor any Debenture registrar shall
be required to exchange or register a transfer of (a) any Debentures for a
period of fifteen (15) days next preceding any selection of Debentures to be
redeemed, (b) any Debentures or portions thereof called for redemption pursuant
to Section 3.02 (c) any Debentures or portions thereof surrendered for
conversion pursuant to Article 15, (d) any Debentures or portions thereof
tendered for redemption (and not withdrawn) pursuant to Section 3.05 or (e) any
Debentures or portions thereof tendered for repurchase (and not withdrawn)
pursuant to Section 3.06.

         (b) The following provisions shall apply only to Global Debentures:

                      (i) Each Global Debenture authenticated under this
         Indenture shall be registered in the name of the Depositary or a
         nominee thereof and delivered to such Depositary or a nominee thereof
         or Custodian therefor, and each such Global Debenture shall constitute
         a single Debenture for all purposes of this Indenture.

                      (ii) Notwithstanding any other provision in this
         Indenture, no Global Debenture may be exchanged in whole or in part for
         Debentures registered, and no transfer of a Global Debenture in whole
         or in part may be registered, in the name of any Person other than the
         Depositary or a nominee thereof unless (A) the Depositary (i) has
         notified the Company that it is unwilling or unable to continue as
         Depositary for such Global


                                       13
<Page>

         Debenture and a successor depositary has not been appointed by the
         Company within ninety days or (ii) has ceased to be a clearing agency
         registered under the Exchange Act, (B) an Event of Default has occurred
         and is continuing or (C) the Company, in its sole discretion, notifies
         the Trustee in writing that it no longer wishes to have all the
         Debentures represented by Global Debentures. Any Global Debenture
         exchanged pursuant to clause (A) or (B) above shall be so exchanged in
         whole and not in part and any Global Debenture exchanged pursuant to
         clause (C) above may be exchanged in whole or from time to time in part
         as directed by the Company. Any Debenture issued in exchange for a
         Global Debenture or any portion thereof shall be a Global Debenture;
         PROVIDED that any such Debenture so issued that is registered in the
         name of a Person other than the Depositary or a nominee thereof shall
         not be a Global Debenture.

                      (iii) Securities issued in exchange for a Global Debenture
         or any portion thereof pursuant to clause (ii) above shall be issued in
         definitive, fully registered form, without interest coupons, shall have
         an aggregate principal amount equal to that of such Global Debenture or
         portion thereof to be so exchanged, shall be registered in such names
         and be in such authorized denominations as the Depositary shall
         designate and shall bear any legends required hereunder. Any Global
         Debenture to be exchanged in whole shall be surrendered by the
         Depositary to the Trustee, as Debenture registrar. With regard to any
         Global Debenture to be exchanged in part, either such Global Debenture
         shall be so surrendered for exchange or, if the Trustee is acting as
         Custodian for the Depositary or its nominee with respect to such Global
         Debenture, the principal amount thereof shall be reduced, by an amount
         equal to the portion thereof to be so exchanged, by means of an
         appropriate adjustment made on the records of the Trustee. Upon any
         such surrender or adjustment, the Trustee shall authenticate and make
         available for delivery the Debenture issuable on such exchange to or
         upon the written order of the Depositary or an authorized
         representative thereof.

                      (iv) In the event of the occurrence of any of the events
         specified in clause (ii) above, the Company will promptly make
         available to the Trustee a reasonable supply of certificated Debentures
         in definitive, fully registered form, without interest coupons.

                      (v) Neither any members of, or participants in, the
         Depositary ("AGENT MEMBERS") nor any other Persons on whose behalf
         Agent Members may act shall have any rights under this Indenture with
         respect to any Global Debenture registered in the name of the
         Depositary or any nominee thereof, and the Depositary or such nominee,
         as the case may be, may be treated by the Company, the Trustee and any
         agent of the Company or the Trustee as the absolute owner and holder of
         such Global Debenture for all purposes whatsoever. Notwithstanding the
         foregoing,


                                       14
<Page>

         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 Depositary
         or such nominee, as the case may be, or impair, as between the
         Depositary, its Agent Members and any other Person on whose behalf an
         Agent Member may act, the operation of customary practices of such
         Persons governing the exercise of the rights of a holder of any
         Debenture.

                      (vi) At such time as all interests in a Global Debenture
         have been redeemed, repurchased, converted, canceled or exchanged for
         Debentures in certificated form, such Global Debenture shall, upon
         receipt thereof, be canceled by the Trustee in accordance with standing
         procedures and instructions existing between the Depositary and the
         Custodian. At any time prior to such cancellation, if any interest in a
         Global Debenture is redeemed, repurchased, converted, canceled or
         exchanged for Debentures in certificated form, the principal amount of
         such Global Debenture shall, in accordance with the standing procedures
         and instructions existing between the Depositary and the Custodian, be
         appropriately reduced, and an endorsement shall be made on such Global
         Debenture, by the Trustee or the Custodian, at the direction of the
         Trustee, to reflect such reduction.

         (c) Every Debenture that bears or is required under this Section
2.05(c) to bear the legend set forth in this Section 2.05(c) (together with any
Common Stock issued upon conversion of the Debentures and required to bear the
legend set forth in Section 2.05(c), collectively, the "RESTRICTED SECURITIES")
shall be subject to the restrictions on transfer set forth in this Section
2.05(c) (including those set forth in the legend below) unless such restrictions
on transfer shall be waived by written consent of the Company, and the holder of
each such Restricted Security, by such Debenture holder's acceptance thereof,
agrees to be bound by all such restrictions on transfer. As used in Section
2.05(c) and 2.05(d), the term "TRANSFER" encompasses any sale, pledge, loan,
transfer or other disposition whatsoever of any Restricted Security or any
interest therein.

         Until the expiration of the holding period applicable to sales thereof
under Rule 144(k) under the Securities Act (or any successor provision), any
certificate evidencing such Debenture (and all securities issued in exchange
therefor or substitution thereof, other than Common Stock, if any, issued upon
conversion thereof, which shall bear the legend set forth in Section 2.05(c), if
applicable) shall bear a legend in substantially the following form, unless such
Debenture has been sold pursuant to a registration statement that has been
declared effective under the Securities Act (and which continues to be effective
at the time of such transfer), or unless otherwise agreed by the Company in
writing, with written notice thereof to the Trustee:

THE DEBENTURE EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE UNITED STATES
SECURITIES ACT OF 1933, AS AMENDED


                                       15
<Page>

(THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS AND, ACCORDINGLY, MAY NOT
BE OFFERED OR SOLD EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT); (2)
AGREES THAT IT WILL NOT, PRIOR TO EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO
SALES OF THIS DEBENTURE UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY
SUCCESSOR PROVISION), RESELL OR OTHERWISE TRANSFER THIS DEBENTURE OR THE COMMON
STOCK ISSUABLE UPON CONVERSION OF THIS DEBENTURE EXCEPT (A) TO AON CORPORATION
OR ANY SUBSIDIARY THEREOF, (B) TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE
WITH RULE 144A UNDER THE SECURITIES ACT, (C) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE) OR (D)
PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE
SECURITIES ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH
TRANSFER); (3) PRIOR TO SUCH TRANSFER (OTHER THAN A TRANSFER PURSUANT TO CLAUSE
(2)(D) ABOVE), IT WILL FURNISH TO THE BANK OF NEW YORK, AS TRUSTEE (OR A
SUCCESSOR TRUSTEE, AS APPLICABLE), SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER
INFORMATION AS THE TRUSTEE MAY REASONABLY REQUIRE 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; AND (4) AGREES THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THIS DEBENTURE IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. THIS LEGEND WILL BE REMOVED UPON THE
EARLIER OF THE TRANSFER OF THIS DEBENTURE PURSUANT TO CLAUSE (2)(D) ABOVE OR
UPON ANY TRANSFER OF THIS DEBENTURE UNDER RULE 144(K) UNDER THE SECURITIES ACT
(OR ANY SUCCESSOR PROVISION). THE INDENTURE CONTAINS A PROVISION REQUIRING THE
TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS DEBENTURE IN VIOLATION OF THE
FOREGOING RESTRICTION.

THIS DEBENTURE WAS ISSUED WITH ORIGINAL ISSUE DISCOUNT FOR U.S. FEDERAL INCOME
TAX PURPOSES. FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL REVENUE
CODE, THE ISSUE PRICE OF EACH DEBENTURE IS $1,000 PER $1,000 OF PRINCIPAL
AMOUNT, THE ISSUE DATE IS NOVEMBER 7, 2002 AND THE COMPARABLE YIELD IS 9.1%,
COMPOUNDED SEMI-ANNUALLY. HOLDERS OF THIS DEBENTURE MAY OBTAIN INFORMATION
REGARDING THE AMOUNT OF ORIGINAL ISSUE DISCOUNT, YIELD TO MATURITY AND THE
PROJECTED PAYMENT SCHEDULE FOR THIS


                                       16
<Page>

DEBENTURE BY SUBMITTING A WRITTEN REQUEST FOR SUCH INFORMATION TO: AON
CORPORATION, CORPORATE SECRETARY, 200 EAST RANDOLPH STREET, CHICAGO, ILLINOIS
60601.

         Any Debenture (or security issued in exchange or substitution therefor)
as to which such restrictions on transfer shall have expired in accordance with
their terms or as to conditions for removal of the foregoing legend set forth
therein have been satisfied may, upon surrender of such Debenture for exchange
to the Debenture registrar in accordance with the provisions of this Section
2.05, be exchanged for a new Debenture or Debentures, of like tenor and
aggregate principal amount, which shall not bear the restrictive legend required
by this Section 2.05(c). If the Restricted Security surrendered for exchange is
represented by a Global Debenture bearing the legend set forth in this Section
2.05(c), the principal amount of the legended Global Debenture shall be reduced
by the appropriate principal amount and the principal amount of a Global
Debenture without the legend set forth in this Section 2.05(c) shall be
increased by an equal principal amount. If a Global Debenture without the legend
set forth in this Section 2.05(c) is not then outstanding, the Company shall
execute and the Trustee shall authenticate and deliver an unlegended Global
Debenture to the Depositary.

            (d) Until the expiration of the holding period applicable to sales
thereof under Rule 144(k) under the Securities Act (or any successor provision),
any stock certificate representing Common Stock issued upon conversion of any
Debenture shall bear a legend in substantially the following form, unless such
Common Stock has been sold pursuant to a registration statement that has been
declared effective under the Securities Act (and which continues to be effective
at the time of such transfer) or such Common Stock has been issued upon
conversion of Debentures that have been transferred pursuant to a registration
statement that has been declared effective under the Securities Act, or unless
otherwise agreed by the Company in writing with written notice thereof to the
transfer agent:

THE COMMON STOCK EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE UNITED
STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT AS SET FORTH
IN THE FOLLOWING SENTENCE. THE HOLDER HEREOF AGREES THAT, UNTIL THE EXPIRATION
OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE COMMON STOCK EVIDENCED HEREBY
UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION), (1) IT
WILL NOT RESELL OR OTHERWISE TRANSFER THE COMMON STOCK EVIDENCED HEREBY EXCEPT
(A) TO AON CORPORATION OR ANY SUBSIDIARY THEREOF, (B) TO A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN
COMPLIANCE WITH RULE 144A, (C) PURSUANT TO THE EXEMPTION FROM REGISTRATION
PROVIDED BY


                                       17
<Page>

RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE) OR (D) PURSUANT TO A
REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES
ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH TRANSFER); (2)
PRIOR TO SUCH TRANSFER (OTHER THAN A TRANSFER PURSUANT TO CLAUSE (1)(D) ABOVE),
IT WILL FURNISH TO EQUISERVE N.A., AS TRANSFER AGENT (OR A SUCCESSOR TRANSFER
AGENT, AS APPLICABLE), SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION
AS SUCH TRANSFER AGENT MAY REASONABLY REQUIRE 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; AND (3) IT WILL DELIVER TO
EACH PERSON TO WHOM THE COMMON STOCK EVIDENCED HEREBY IS TRANSFERRED (OTHER THAN
A TRANSFER PURSUANT TO CLAUSE (1)(D) ABOVE) A NOTICE SUBSTANTIALLY TO THE EFFECT
OF THIS LEGEND. THIS LEGEND WILL BE REMOVED UPON THE EARLIER OF THE TRANSFER OF
THE COMMON STOCK EVIDENCED HEREBY PURSUANT TO CLAUSE (1)(D) ABOVE OR UPON ANY
TRANSFER OF THE COMMON STOCK EVIDENCED HEREBY AFTER THE EXPIRATION OF THE
HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE
144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION).

         Any such Common Stock as to which such restrictions on transfer shall
have expired in accordance with their terms or as to which the conditions for
removal of the foregoing legend set forth therein have been satisfied may, upon
surrender of the certificates representing such shares of Common Stock for
exchange in accordance with the procedures of the transfer agent for the Common
Stock, be exchanged for a new certificate or certificates for a like number of
shares of Common Stock, which shall not bear the restrictive legend required by
this Section 2.05(d).

            (e) Any Debenture or Common Stock issued upon the conversion of a
Debenture that, prior to the expiration of the holding period applicable to
sales thereof under Rule 144(k) under the Securities Act (or any successor
provision), is purchased or owned by the Company or any Affiliate thereof may
not be resold by the Company or such Affiliate unless registered under the
Securities Act or resold pursuant to an exemption from the registration
requirements of the Securities Act in a transaction which results in such
Debentures or Common Stock, as the case may be, no longer being "RESTRICTED
SECURITIES" (as defined under Rule 144).

         Section 2.06. MUTILATED, DESTROYED, LOST OR STOLEN DEBENTURES. In case
any Debenture shall become mutilated or be destroyed, lost or stolen, the
Company in its discretion may execute, and upon its written request the Trustee
or an authenticating agent appointed by the Trustee shall authenticate and make


                                       18
<Page>

available for delivery, a new Debenture, bearing a number not contemporaneously
outstanding, in exchange and substitution for the mutilated Debenture, or in
lieu of and in substitution for the Debenture so destroyed, lost or stolen. In
every case, the applicant for a substituted Debenture shall furnish to the
Company, to the Trustee and, if applicable, to such authenticating agent such
security or indemnity as may be required by them to save each of them harmless
for any loss, liability, cost or expense caused by or connected with such
substitution, and, in every case of destruction, loss or theft, the applicant
shall also furnish to the Company, to the Trustee and, if applicable, to such
authenticating agent evidence to their satisfaction of the destruction, loss or
theft of such Debenture and of the ownership thereof.

         Following receipt by the Trustee or such authenticating agent, as the
case may be, of satisfactory security or indemnity and evidence, as described in
the preceding paragraph, the Trustee or such authenticating agent may
authenticate any such substituted Debenture and make available for delivery such
Debenture. Upon the issuance of any substituted Debenture, the Company may
require the payment by the holder of a sum sufficient to cover any tax,
assessment or other governmental charge that may be imposed in relation thereto
and any other expenses connected therewith. In case any Debenture which has
matured or is about to mature or has been called for redemption or has been
tendered for redemption upon a Fundamental Change (and not withdrawn) or has
been surrendered for repurchase on a Repurchase Date (and not withdrawn) or is
to be converted into Common Stock shall become mutilated or be destroyed, lost
or stolen, the Company may, instead of issuing a substitute Debenture, pay or
authorize the payment of or convert or authorize the conversion of the same
(without surrender thereof except in the case of a mutilated Debenture), as the
case may be, if the applicant for such payment or conversion shall furnish to
the Company, to the Trustee and, if applicable, to such authenticating agent
such security or indemnity as may be required by them to save each of them
harmless for any loss, liability, cost or expense caused by or in connection
with such substitution, and, in every case of destruction, loss or theft, the
applicant shall also furnish to the Company, the Trustee and, if applicable, any
paying agent or conversion agent evidence to their satisfaction of the
destruction, loss or theft of such Debenture and of the ownership thereof.

         Every substitute Debenture issued pursuant to the provisions of this
Section 2.06 by virtue of the fact that any Debenture is destroyed, lost or
stolen shall constitute an additional contractual obligation of the Company,
whether or not the destroyed, lost or stolen Debenture shall be found at any
time, and shall be entitled to all the benefits of (but shall be subject to all
the limitations set forth in) this Indenture equally and proportionately with
any and all other Debentures duly issued hereunder. To the extent permitted by
law, all Debentures shall be held and owned upon the express condition that the
foregoing provisions are exclusive with respect to the replacement or payment or
conversion or redemption or repurchase of mutilated, destroyed, lost or stolen
Debentures and shall preclude


                                       19
<Page>

any and all other rights or remedies notwithstanding any law or statute existing
or hereafter enacted to the contrary with respect to the replacement or payment
or conversion or redemption or repurchase of negotiable instruments or other
securities without their surrender.

         Section 2.07. TEMPORARY DEBENTURES. Pending the preparation of
Debentures in certificated form, the Company may execute and the Trustee or an
authenticating agent appointed by the Trustee shall, upon the written request of
the Company, authenticate and deliver temporary Debentures (printed or
lithographed). Temporary Debentures shall be issuable in any authorized
denomination, and substantially in the form of the Debentures in certificated
form, but with such omissions, insertions and variations as may be appropriate
for temporary Debentures, all as may be determined by the Company. Every such
temporary Debenture shall be executed by the Company and authenticated by the
Trustee or such authenticating agent upon the same conditions and in
substantially the same manner, and with the same effect, as the Debentures in
certificated form. Without unreasonable delay, the Company will execute and
deliver to the Trustee or such authenticating agent Debentures in certificated
form and thereupon any or all temporary Debentures may be surrendered in
exchange therefor, at each office or agency maintained by the Company pursuant
to Section 5.02 and the Trustee or such authenticating agent shall authenticate
and make available for delivery in exchange for such temporary Debentures an
equal aggregate principal amount of Debentures in certificated form. Such
exchange shall be made by the Company at its own expense and without any charge
therefor. Until so exchanged, the temporary Debentures shall in all respects be
entitled to the same benefits and subject to the same limitations under this
Indenture as Debentures in certificated form authenticated and delivered
hereunder.

         Section 2.08. CANCELLATION OF DEBENTURES. All Debentures surrendered
for the purpose of payment, redemption, repurchase, conversion, exchange or
registration of transfer shall, if surrendered to the Company or any paying
agent or any Debenture registrar or any conversion agent, be surrendered to the
Trustee and promptly canceled by it, or, if surrendered to the Trustee, shall be
promptly canceled by it, and no Debentures shall be issued in lieu thereof
except as expressly permitted by any of the provisions of this Indenture. The
Trustee shall dispose of such canceled Debentures in accordance with its
customary procedures. If the Company shall acquire any of the Debentures, such
acquisition shall not operate as a redemption, repurchase or satisfaction of the
indebtedness represented by such Debentures unless and until the same are
delivered to the Trustee for cancellation.

         Section 2.09. CUSIP NUMBERS. The Company in issuing the Debentures may
use "CUSIP" numbers (if then generally in use), and, if so, the Trustee shall
use "CUSIP" numbers in notices of redemption as a convenience to
Debentureholders; PROVIDED that any such notice may state that no representation
is made as to the correctness of such numbers either as printed on the
Debentures or as contained in any notice of a redemption and that reliance may
be placed only


                                       20
<Page>

on the other identification numbers printed on the Debentures, and any such
redemption shall not be affected by any defect in or omission of such numbers.
The Company will promptly notify the Trustee of any change in the "CUSIP"
numbers.


                                    ARTICLE 3
                     REDEMPTION AND REPURCHASE OF DEBENTURES

         Section 3.01. REDEMPTION OF DEBENTURES. Except as otherwise provided in
Section 3.05, the Company may not redeem any Debentures prior to November 19,
2007. At any time on or after November 19, 2007 and prior to maturity, the
Debentures may be redeemed at the option of the Company, in whole or in part,
upon notice as set forth in Section 3.02, at the redemption prices set forth in
the form of Debenture attached as Exhibit A hereto, together with accrued and
unpaid interest, if any, to, but excluding the date fixed for redemption.

         Section 3.02. NOTICE OF OPTIONAL REDEMPTION; SELECTION OF DEBENTURES.
In case the Company shall desire to exercise the right to redeem all or, as the
case may be, any part of the Debentures pursuant to Section 3.01, it shall fix a
date for redemption and it or, at its written request received by the Trustee
not fewer than forty-five (45) days prior (or such shorter period of time as may
be acceptable to the Trustee) to the date fixed for redemption, the Trustee in
the name of and at the expense of the Company, shall mail or cause to be mailed
a notice of such redemption not fewer than thirty (30) nor more than sixty (60)
days prior to the redemption date to each holder of Debentures so to be redeemed
as a whole or in part at its last address as the same appears on the Debenture
register; PROVIDED that if the Company shall give such notice, it shall also
give written notice of the redemption date to the Trustee. Such mailing shall be
by first class mail. The notice, if mailed in the manner herein provided, shall
be conclusively presumed to have been duly given, whether or not the holder
receives such notice. In any case, failure to give such notice by mail or any
defect in the notice to the holder of any Debenture designated for redemption as
a whole or in part shall not affect the validity of the proceedings for the
redemption of any other Debenture. Concurrently with the mailing of any such
notice of redemption, the Company shall issue a press release announcing such
redemption, the form and content of which press release shall be determined by
the Company in its sole discretion. The failure to issue any such press release
or any defect therein shall not affect the validity of the redemption notice or
any of the proceedings for the redemption of any Debenture called for
redemption.

         Each such notice of redemption shall specify the aggregate principal
amount of Debentures to be redeemed, the CUSIP number or numbers of the
Debentures being redeemed, the date fixed for redemption (which shall be a
Business Day), the redemption price at which Debentures are to be redeemed, the
place or places of payment, that payment will be made upon presentation and


                                       21
<Page>

surrender of such Debentures, that interest accrued to the date fixed for
redemption will be paid as specified in said notice, and that on and after said
date interest thereon or on the portion thereof to be redeemed will cease to
accrue. Such notice shall also state the current Conversion Rate and the date on
which the right to convert such Debentures or portions thereof into Common Stock
will expire. If fewer than all the Debentures are to be redeemed, the notice of
redemption shall identify the Debentures to be redeemed (including CUSIP
numbers, if any). In case any Debenture is to be redeemed in part only, the
notice of redemption shall state the portion of the principal amount thereof to
be redeemed and shall state that, on and after the redemption date, upon
surrender of such Debenture, a new Debenture or Debentures in principal amount
equal to the unredeemed portion thereof will be issued.

         On or prior to the redemption date specified in the notice of
redemption given as provided in this Section 3.02, the Company will deposit with
the Trustee or with one or more paying agents (or, if the Company is acting as
its own paying agent, set aside, segregate and hold in trust as provided in
Section 5.04) an amount of money in immediately available funds sufficient to
redeem on the redemption date all the Debentures (or portions thereof) so called
for redemption (other than those theretofore surrendered for conversion into
Common Stock) at the appropriate redemption price, together with accrued
interest to, but excluding, the redemption date; PROVIDED that if such payment
is made on the redemption date it must be received by the Trustee or paying
agent, as the case may be, by 10:00 a.m. New York City time on such date. The
Company shall be entitled to retain any interest, yield or gain on amounts
deposited with the Trustee or any paying agent pursuant to this Section 3.02 in
excess of amounts required hereunder to pay the redemption price and accrued
interest to, but excluding, the redemption date. If any Debenture called for
redemption is converted pursuant hereto prior to such redemption date, any money
deposited with the Trustee or any paying agent or so segregated and held in
trust for the redemption of such Debenture shall be paid to the Company upon its
written request, or, if then held by the Company, shall be discharged from such
trust. Whenever any Debentures are to be redeemed, the Company will give the
Trustee written notice in the form of an Officers' Certificate not fewer than
forty-five (45) days (or such shorter period of time as may be acceptable to the
Trustee) prior to the redemption date as to the aggregate principal amount of
Debentures to be redeemed.

         If less than all of the outstanding Debentures are to be redeemed, the
Trustee shall select the Debentures or portions thereof of the Global Debenture
or the Debentures in certificated form to be redeemed (in principal amounts of
$1,000 or multiples thereof) by lot, on a pro rata basis or by another method
the Trustee deems fair and appropriate. If any Debenture selected for partial
redemption is submitted for conversion in part after such selection, the portion
of such Debenture submitted for conversion shall be deemed (so far as may be
possible) to be the portion to be selected for redemption. The Debentures (or
portions thereof) so selected shall be deemed duly selected for redemption for
all


                                       22
<Page>

purposes hereof, notwithstanding that any such Debenture is submitted for
conversion in part before the mailing of the notice of redemption.

         Upon any redemption of less than all of the outstanding Debentures, the
Company and the Trustee may (but need not), solely for purposes of determining
the pro rata allocation among such Debentures as are unconverted and outstanding
at the time of redemption, treat as outstanding any Debentures surrendered for
conversion during the period of fifteen (15) days next preceding the mailing of
a notice of redemption and may (but need not) treat as outstanding any Debenture
authenticated and delivered during such period in exchange for the unconverted
portion of any Debenture converted in part during such period.

         Section 3.03. PAYMENT OF DEBENTURES CALLED FOR REDEMPTION BY THE
COMPANY. If notice of redemption has been given as provided in Section 3.02, the
Debentures or portion of Debentures with respect to which such notice has been
given shall, unless converted into Common Stock pursuant to the terms hereof,
become due and payable on the date fixed for redemption and at the place or
places stated in such notice at the applicable redemption price, together with
interest accrued to (but excluding) the redemption date, and on and after said
date (unless the Company shall default in the payment of such Debentures at the
redemption price, together with interest accrued to said date) interest on the
Debentures or portion of Debentures so called for redemption shall cease to
accrue and, after the close of business on the Business Day immediately
preceding the redemption date (unless the Company shall default in the payment
of such Debentures at the redemption price, together with interest accrued to
said date) such Debentures shall cease to be convertible into Common Stock and,
except as provided in Section 8.05 and 13.04, to be entitled to any benefit or
security under this Indenture, and the holders thereof shall have no right in
respect of such Debentures except the right to receive the redemption price
thereof and unpaid interest to (but excluding) the redemption date. On
presentation and surrender of such Debentures at a place of payment in said
notice specified, the said Debentures or the specified portions thereof shall be
paid and redeemed by the Company at the applicable redemption price, together
with interest accrued thereon to, but excluding, the redemption date; PROVIDED
that if the applicable redemption date is an interest payment date, the interest
payable on such interest payment date shall be payable to the holders of record
of such Debentures on the applicable record date instead of the holders
surrendering such Debentures for redemption on such date.

         Upon presentation of any Debenture redeemed in part only, the Company
shall execute and the Trustee shall authenticate and make available for delivery
to the holder thereof, at the expense of the Company, a new Debenture or
Debentures, of authorized denominations, in principal amount equal to the
unredeemed portion of the Debentures so presented.

         Notwithstanding the foregoing, the Trustee shall not redeem any
Debentures or mail any notice of redemption during the continuance of a default


                                       23
<Page>

in payment of interest or premium, if any, on the Debentures. If any Debenture
called for redemption shall not be so paid upon surrender thereof for
redemption, the principal and premium, if any, shall, until paid or duly
provided for, bear interest from the redemption date at a rate equal to 1% per
annum plus the rate borne by the Debenture and such Debenture shall remain
convertible into Common Stock until the principal and premium, if any, and
interest shall have been paid or duly provided for.

         Section 3.04. CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION. In
connection with any redemption of Debentures, the Company may arrange for the
purchase and conversion of any Debentures by an agreement with one or more
investment banks or other purchasers to purchase such Debentures by paying to
the Trustee in trust for the Debentureholders, on or before the date fixed for
redemption, an amount not less than the applicable redemption price, together
with interest accrued to, but excluding, the date fixed for redemption, of such
Debentures. Notwithstanding anything to the contrary contained in this Article
3, the obligation of the Company to pay the redemption price of such Debentures,
together with interest accrued to, but excluding, the date fixed for redemption,
shall be deemed to be satisfied and discharged to the extent such amount is so
paid by such purchasers. If such an agreement is entered into, a copy of which
will be filed with the Trustee prior to the date fixed for redemption, any
Debentures not duly surrendered for conversion by the holders thereof may, at
the option of the Company, be deemed, to the fullest extent permitted by law,
acquired by such purchasers from such holders and (notwithstanding anything to
the contrary contained in Article 15) surrendered by such purchasers for
conversion, all as of immediately prior to the close of business on the date
fixed for redemption (and the right to convert any such Debentures shall be
extended through such time), subject to payment of the above amount as
aforesaid. At the direction of the Company, the Trustee shall hold and dispose
of any such amount paid to it in the same manner as it would monies deposited
with it by the Company for the redemption of Debentures. Without the Trustee's
prior written consent, no arrangement between the Company and such purchasers
for the purchase and conversion of any Debentures shall increase or otherwise
affect any of the powers, duties, responsibilities or obligations of the Trustee
as set forth in this Indenture.

         Section 3.05. REDEMPTION AT OPTION OF HOLDERS UPON A FUNDAMENTAL
CHANGE. (a) If there shall occur a Fundamental Change at any time prior to
maturity of the Debentures, then each Debentureholder shall have the right, at
such holder's option, to require the Company to redeem all of such holder's
Debentures, or any portion thereof that is a multiple of $1,000 principal
amount, on the date (the "FUNDAMENTAL CHANGE REDEMPTION DATE") that is thirty
(30) days after the date of the Fundamental Change Notice (as defined in Section
3.05(b)) of such Fundamental Change (or, if such 30th day is not a Business Day,
the next succeeding Business Day) at a redemption price equal to 100% of the
principal amount thereof, together with accrued interest to, but excluding, the


                                       24
<Page>

Fundamental Change Redemption Date; PROVIDED that if such Fundamental Change
Redemption Date is an interest payment date, then the interest payable on such
interest payment date shall be paid to the holders of record of the Debentures
on the applicable record date instead of the holders surrendering the Debentures
for redemption on such date.

         Upon presentation of any Debenture redeemed in part only, the Company
shall execute and, upon the Company's written direction to the Trustee, the
Trustee shall authenticate and make available for delivery to the holder
thereof, at the expense of the Company, a new Debenture or Debentures, of
authorized denominations, in aggregate principal amount equal to the unredeemed
portion of the Debentures presented.

            (b) On or before the tenth day after the occurrence of a Fundamental
Change, the Company or at its written request (which must be received by the
Trustee at least five (5) Business Days prior to the date the Trustee is
requested to give notice as described below, unless the Trustee shall agree in
writing to a shorter period), the Trustee, in the name of and at the expense of
the Company, shall mail or cause to be mailed to all holders of record on the
date of the Fundamental Change a notice (the "FUNDAMENTAL CHANGE NOTICE") of the
occurrence of such Fundamental Change and of the redemption right at the option
of the holders arising as a result thereof. Such notice shall be mailed in the
manner and with the effect set forth in the first paragraph of Section 3.02
(without regard for the time limits set forth therein). If the Company shall
give such notice, the Company shall also deliver a copy of the Fundamental
Change Company Notice to the Trustee at such time as it is mailed to
Debentureholders. Concurrently with the mailing of any Fundamental Change
Notice, the Company shall issue a press release announcing such Fundamental
Change referred to in the Fundamental Change Notice, the form and content of
which press release shall be determined by the Company in its sole discretion.
The failure to issue any such press release or any defect therein shall not
affect the validity of the Fundamental Change Notice or any proceedings for the
redemption of any Debenture which any Debentureholder may elect to have the
Company redeem as provided in this Section 3.05.

         Each Fundamental Change Notice shall specify the circumstances
constituting the Fundamental Change, the Fundamental Change Redemption Date, the
price at which the Company shall be obligated to redeem Debentures, that the
holder must exercise the redemption right on or prior to the close of business
on the Fundamental Change Redemption Date (the "FUNDAMENTAL CHANGE EXPIRATION
TIME"), that the holder shall have the right to withdraw any Debentures
surrendered prior to the Fundamental Change Expiration Time, a description of
the procedure which a Debentureholder must follow to exercise such redemption
right and to withdraw any surrendered Debentures, the place or places where the
holder is to surrender such holder's Debentures, the amount of interest accrued
on each Debenture to the Fundamental Change Redemption Date and the CUSIP number
or numbers of the Debentures (if then generally in use).


                                       25
<Page>

         No failure of the Company to give the foregoing notices and no defect
therein shall limit the Debentureholders' redemption rights or affect the
validity of the proceedings for the redemption of the Debentures pursuant to
this Section 3.05.

            (c) For a Debenture, other than a Global Debenture to be so redeemed
at the option of the holder, the Company must receive at the office or agency of
the Company maintained for that purpose or, at the option of such holder, the
Corporate Trust Office, such Debenture with the form entitled "OPTION TO ELECT
REPAYMENT UPON A FUNDAMENTAL CHANGE" on the reverse thereof duly completed,
together with such Debentures duly endorsed for transfer, on or before the
Fundamental Change Expiration Time. All questions as to the validity,
eligibility (including time of receipt) and acceptance of any Debenture for
redemption shall be determined by the Company, whose determination shall be
final and binding absent manifest error.

            (d) On or prior to the Fundamental Change Redemption Date, the
Company will deposit with the Trustee or with one or more paying agents (or, if
the Company is acting as its own paying agent, set aside, segregate and hold in
trust as provided in Section 5.04) an amount of money sufficient to redeem on
the Fundamental Change Redemption Date all the Debentures to be redeemed on such
date at the appropriate redemption price, together with accrued interest to, but
excluding, the Fundamental Change Redemption Date; PROVIDED that if such payment
is made on the Fundamental Change Redemption Date it must be received by the
Trustee or paying agent, as the case may be, by 10:00 a.m. New York City time,
on such date. Payment for Debentures surrendered for redemption (and not
withdrawn) prior to the Fundamental Change Expiration Time will be made promptly
(but in no event more than five (5) Business Days) following the Repurchase Date
by mailing checks for the amount payable to the holders of such Debentures
entitled thereto as they shall appear in the Debenture register.

            (e) In the case of a reclassification, change, consolidation,
merger, combination, sale or conveyance to which Section 15.06 applies, in which
the Common Stock of the Company is changed or exchanged as a result into the
right to receive stock, securities or other property or assets (including cash),
which includes shares of Common Stock of the Company or shares of common stock
of another Person that are, or upon issuance will be, traded on a United States
national securities exchange or approved for trading on an established automated
over-the-counter trading market in the United States and such shares constitute
at the time such change or exchange becomes effective in excess of 50% of the
aggregate fair market value of such stock, securities or other property or
assets (including cash) (as determined by the Company, which determination shall
be conclusive and binding), then the Person formed by such consolidation or
resulting from such merger or which acquires such assets, as the case may be,
shall execute and deliver to the Trustee a supplemental indenture (accompanied
by an Opinion of Counsel that such supplemental indenture complies with the
Trust Indenture Act as in force at the date of execution of such supplemental


                                       26
<Page>

indenture) modifying the provisions of this Indenture relating to the right of
holders of the Debentures to cause the Company to repurchase the Debentures
following a Fundamental Change, including without limitation the applicable
provisions of this Section 3.05 and the definitions of Common Stock and
Fundamental Change, as appropriate, as determined in good faith by the Company
(which determination shall be conclusive and binding), to make such provisions
apply to such other Person if different from the Company and the common stock
issued by such Person (in lieu of the Company and the Common Stock of the
Company).

            (f) The Company will comply with the provisions of Rule 13e-4 and
any other tender offer rules under the Exchange Act to the extent then
applicable in connection with the redemption rights of the holders of Debentures
in the event of a Fundamental Change.

         Section 3.06. REPURCHASE OF DEBENTURES BY THE COMPANY AT OPTION OF THE
HOLDER. Debentures shall be purchased by the Company pursuant to the terms of
the Debentures at the option of the holder on November 15, 2009 (the "REPURCHASE
DATE"), at a purchase price of 100% of the principal amount, plus any accrued
and unpaid interest to, but excluding, the Repurchase Date, subject to the
provisions of Section 3.07(a). Repurchases of Debentures under this Section 3.06
shall be made, at the option of the holder thereof, upon:

            (a) delivery to the Trustee (or other paying agent appointed by the
Company) by a holder of a duly completed notice (the "REPURCHASE NOTICE") in the
form set forth on the reverse of the Debenture during the period beginning at
any time from the opening of business on the date that is 20 Business Days prior
to the Repurchase Date until the close of business on the Repurchase Date; and

            (b) delivery or book-entry transfer of the Debentures to the Trustee
(or other paying agent appointed by the Company) at any time after delivery of
the Repurchase Notice (together with all necessary endorsements) at the
Corporate Trust Office of the Trustee (or other paying agent appointed by the
Company) in the Borough of Manhattan as provided in Section 5.02, such delivery
being a condition to receipt by the holder of the purchase price therefor;
PROVIDED that such purchase price shall be so paid pursuant to this Section 3.06
only if the Debenture so delivered to the Trustee (or other paying agent
appointed by the Company) shall conform in all respects to the description
thereof in the related Repurchase Notice.

         The Company shall purchase from the holder thereof, pursuant to this
Section 3.06, a portion of a Debenture, if the principal amount of such portion
is $1,000 or a whole multiple of $1,000. Provisions of this Indenture that apply
to the purchase of all of a Debenture also apply to the purchase of such portion
of such Debenture.


                                       27
<Page>

         Any purchase by the Company contemplated pursuant to the provisions of
this Section 3.06 shall be consummated by the delivery of the consideration to
be received by the holder promptly following the later of the Repurchase Date
and the time of the book-entry transfer or delivery of the Debenture.

         Notwithstanding anything herein to the contrary, any holder delivering
to the Trustee (or other paying agent appointed by the Company) the Repurchase
Notice contemplated by this Section 3.06 shall have the right to withdraw such
Repurchase Notice at any time prior to the close of business on the Repurchase
Date by delivery of a written notice of withdrawal to the Trustee (or other
paying agent appointed by the Company) in accordance with Section 3.08.

         The Trustee (or other paying agent appointed by the Company) shall
promptly notify the Company of the receipt by it of any Repurchase Notice or
written notice of withdrawal thereof.

         Section 3.07.  COMPANY REPURCHASE NOTICE.

         (a) The Debentures to be repurchased on the Repurchase Date pursuant to
Section 3.06 will be paid for in cash.

         At least three Business Days before the Company Repurchase Notice Date,
the Company shall deliver an Officers' Certificate to the Trustee specifying:

                  (i) the information required by Section 3.07(b) in the Company
         Repurchase Notice, and

                  (ii) whether the Company desires the Trustee to give the
         Company Repurchase Notice required by Section 3.07(b).

         (b) In connection with any repurchase of Debentures, the Company shall,
no less than 20 Business Days prior to each Repurchase Date (the "COMPANY
REPURCHASE NOTICE DATE"), give notice to holders at their addresses shown in the
Debenture Register setting forth information specified in this Section 3.07(b)
(the "COMPANY REPURCHASE NOTICE"). The Company will also give notice to
beneficial owners as required by applicable law.

         Each Company Repurchase Notice shall:

                  (1) state the repurchase price and the Repurchase Date to
         which the Company Repurchase Notice relates;

                  (2) include a form of Repurchase Notice;

                  (3) state the name and address of the Trustee (or other paying
         agent or conversion agent appointed by the Company);


                                       28
<Page>

                  (4) state that Debentures must be surrendered to the Trustee
         (or other paying agent appointed by the Company) to collect the
         purchase price;

                  (5) if the Debentures are then convertible, state that
         Debentures as to which a Repurchase Notice has been given may be
         converted only if the Repurchase Notice is withdrawn in accordance with
         the terms of this Indenture; and

                  (6) state the CUSIP number of the Debentures.

Company Repurchase Notices may be given by the Company or, at the Company's
request, the Trustee shall give such Company Repurchase Notice in the Company's
name and at the Company's expense.

         (c) The Company will comply with the provisions of Rule 13e-4 and any
other tender offer rules under the Exchange Act to the extent then applicable in
connection with the repurchase rights of the holders of Debentures.

         Section 3.08. EFFECT OF REPURCHASE NOTICE. Upon receipt by the Trustee
(or other paying agent appointed by the Company) of the Repurchase Notice
specified in Section 3.06, the holder of the Debenture in respect of which such
Repurchase Notice was given shall (unless such Repurchase Notice is validly
withdrawn) thereafter be entitled to receive solely the purchase price with
respect to such Debenture. Such purchase price shall be paid to such holder,
subject to receipt of funds and/or Debentures by the Trustee (or other paying
agent appointed by the Company), promptly following the later of (x) the
Repurchase Date with respect to such Debenture (provided the holder has
satisfied the conditions in Section 3.06) and (y) the time of delivery of such
Debenture to the Trustee (or other paying agent appointed by the Company) by the
holder thereof in the manner required by Section 3.06. Debentures in respect of
which a Repurchase Notice has been given by the holder thereof may not be
converted pursuant to Article 15 hereof on or after the date of the delivery of
such Repurchase Notice unless such Repurchase Notice has first been validly
withdrawn.

         A Repurchase Notice may be withdrawn by means of a written notice of
withdrawal delivered to the office of the Trustee (or other paying agent
appointed by the Company) in accordance with the Repurchase Notice at any time
prior to the close of business on the Repurchase Date, specifying:

         (a) the certificate number, if any, of the Debenture in respect of
which such notice of withdrawal is being submitted, or the appropriate
Depositary information if the Debenture in respect of which such notice of
withdrawal is being submitted is represented by a Global Debenture,


                                       29
<Page>

         (b) the principal amount of the Debenture with respect to which such
notice of withdrawal is being submitted, and

         (c) the principal amount, if any, of such Debenture which remains
subject to the original Repurchase Notice and which has been or will be
delivered for purchase by the Company.

         A written notice of withdrawal of a Repurchase Notice may be in the
form set forth in the preceding paragraph or may be in the form of a conditional
withdrawal contained in a Repurchase Notice pursuant to the terms of Section
3.06(a).

         Section 3.09. DEPOSIT OF PURCHASE PRICE. (a) Prior to 10:00 a.m. (New
York City Time) on the Business Day following the Repurchase Date, the Company
shall deposit with the Trustee (or other paying agent appointed by the Company;
or, if the Company or a Subsidiary or an Affiliate of either of them is acting
as the paying agent, shall segregate and hold in trust as provided in Section
5.04) an amount of cash (in immediately available funds if deposited on such
Business Day), sufficient to pay the aggregate purchase price of all the
Debentures or portions thereof that are to be purchased as of the Repurchase
Date.

         (b) If the Trustee or other paying agent appointed by the Company, or
the Company or a Subsidiary or Affiliate of either of them, if such entity is
acting as the paying agent, holds cash sufficient to pay the aggregate purchase
price of all the Debentures, or portions thereof that are to be purchased as of
the Repurchase Date, on or after the Repurchase Date (i) the Debentures will
cease to be outstanding, (ii) interest on the Debentures will cease to accrue,
and (iii) all other rights of the holders of such Debentures will terminate,
whether or not book-entry transfer of the Debentures has been made or the
Debentures have been delivered to the Trustee or paying agent, other than the
right to receive the repurchase price upon delivery of the Debentures.

         Section 3.10. DEBENTURES REPURCHASED IN PART. Upon presentation of any
Debenture repurchased only in part, the Company shall execute and the Trustee
shall authenticate and make available for delivery to the holder thereof, at the
expense of the Company, a new Debenture or Debentures, of any authorized
denomination, in aggregate principal amount equal to the unrepurchased portion
of the Debentures presented.

         Section 3.11. REPAYMENT TO THE COMPANY. The Trustee (or other paying
agent appointed by the Company) shall return to the Company any cash that
remains unclaimed as provided in Section 12 of the Debentures, together with
interest, if any, thereon, held by them for the payment of the purchase price;
PROVIDED that to the extent that the aggregate amount of cash deposited by the
Company pursuant to Section 3.09 exceeds the aggregate purchase price of the
Debentures or portions thereof which the Company is obligated to purchase as of
the Repurchase Date then, unless otherwise agreed in writing with the Company,


                                       30
<Page>

promptly after the Business Day following the Repurchase Date, the Trustee shall
return any such excess to the Company together with interest, if any, thereon.



                                    ARTICLE 4
                               CONTINGENT INTEREST

         Section 4.01. CONTINGENT INTEREST. Beginning with the six-month
interest period commencing November 15, 2007, the Company will pay contingent
interest during a six month interest period if the Trading Price for each of the
five Trading Days immediately preceding the first day of the applicable
six-month interest period equals or exceeds 120% of the principal amount of the
Debentures; PROVIDED that if the Company should declare a dividend on the Common
Stock for which the record date falls prior to the first day of a six-month
interest period, but the payment date for such dividend falls within such
six-month interest period, then the five Trading Day measuring period shall be
the five Trading Day period immediately preceding the dividend record date.
During any six-month interest period when contingent interest is payable, the
contingent interest payable on each $1,000 principal amount of Debenture shall
equal the greater of (1) 0.25% of the average Trading Price for $1,000 principal
amount of Debentures during the five Trading Day measuring period immediately
preceding the beginning of applicable six-month interest period used to
determine whether contingent interest must be paid or (2) the sum of all Regular
Cash Dividends paid by the Company per share on the Common Stock during the
applicable six-month interest period multiplied by the number of shares of
Common Stock issuable upon conversion of a $1,000 principal amount Debentures at
the then applicable Conversion Rate on the payment date for each such Regular
Cash Dividend.

         "REGULAR CASH DIVIDEND" means quarterly or other periodic cash
dividends paid on the Common Stock as declared by the Board of Directors in
accordance with the Company's cash dividend policy in effect from time to time
and shall exclude any cash dividend determined by the Board of Directors to be
extraordinary, special or nonrecurring, such determination to be conclusive.

         Section 4.02. PAYMENT OF CONTINGENT INTEREST. Contingent interest for
any six-month interest period shall be paid on the last day of any six month
interest period to the Person in whose name any Debenture (or its Predecessor
Debenture) is registered on the Debenture register at the close of business on
the day immediately preceding such day. Contingent interest due under this
Article 4 shall be treated for all purposes of this Indenture like any other
interest accruing on the Debentures.

         Section 4.03. CONTINGENT INTEREST NOTIFICATION. By the first Business
Day of a six-month interest period during which contingent interest will be
paid, the Company will disseminate a press release through Dow Jones & Company,
Inc. or Bloomberg Business News stating that contingent interest will be paid on
the Debentures and identifying the six month interest period.


                                       31
<Page>

                                    ARTICLE 5
                       PARTICULAR COVENANTS OF THE COMPANY

         Section 5.01. PAYMENT OF PRINCIPAL, PREMIUM AND INTEREST. The Company
covenants and agrees that it will duly and punctually pay or cause to be paid
the principal of and premium, if any (including the redemption price upon
redemption or the purchase price upon repurchase, in each case pursuant to
Article 3), and interest, on each of the Debentures at the places, at the
respective times and in the manner provided herein and in the Debentures.

         Section 5.02. MAINTENANCE OF OFFICE OR AGENCY. The Company will
maintain an office or agency in the Borough of Manhattan, the City of New York,
where the Debentures may be surrendered for registration of transfer or exchange
or for presentation for payment or for conversion, redemption or repurchase and
where notices and demands to or upon the Company in respect of the Debentures
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 not designated or appointed by the Trustee. 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 or the
corporate trust office of the Trustee in The Borough of Manhattan which office
is located at 101 Barclay Street, Floor 21W, New York, NY 10286.

         The Company may also from time to time designate co-registrars and one
or more offices or agencies where the Debentures may be presented or surrendered
for any or all such purposes and may from time to time rescind such
designations. The Company will give prompt written notice of any such
designation or rescission and of any change in the location of any such other
office or agency.

         The Company hereby initially designates the Trustee as paying agent,
Debenture registrar, Custodian and conversion agent and each of the Corporate
Trust Office and the office of agency of the Trustee in The Borough of
Manhattan, shall be considered as one such office or agency of the Company for
each of the aforesaid purposes.

         So long as the Trustee is the Debenture registrar, the Trustee agrees
to mail, or cause to be mailed, the notices set forth in Section 8.10(a) and the
third paragraph of Section 8.11. If co-registrars have been appointed in
accordance with this Section, the Trustee shall mail such notices only to the
Company and the holders of Debentures it can identify from its records.

         Section 5.03. APPOINTMENTS TO FILL VACANCIES IN TRUSTEE'S OFFICE. The
Company, whenever necessary to avoid or fill a vacancy in the office of Trustee,
will appoint, in the manner provided in Section 8.10, a Trustee, so that there
shall at all times be a Trustee hereunder.


                                       32
<Page>

         Section 5.04. PROVISIONS AS TO PAYING AGENT. (a) If the Company shall
appoint a paying agent other than the Trustee, or if the Trustee shall appoint
such a paying agent, the Company will cause such paying agent to execute and
deliver to the Trustee an instrument in which such agent shall agree with the
Trustee, subject to the provisions of this Section 5.04:

                  (1) that it will hold all sums held by it as such agent for
         the payment of the principal of and premium, if any, or interest on the
         Debentures (whether such sums have been paid to it by the Company or by
         any other obligor on the Debentures) in trust for the benefit of the
         holders of the Debentures;

                  (2) that it will give the Trustee notice of any failure by the
         Company (or by any other obligor on the Debentures) to make any payment
         of the principal of and premium, if any, or interest on the Debentures
         when the same shall be due and payable; and

                  (3) that at any time during the continuance of an Event of
         Default, upon request of the Trustee, it will forthwith pay to the
         Trustee all sums so held in trust.

         The Company shall, on or before each due date of the principal of,
premium, if any, or interest on the Debentures, deposit with the paying agent a
sum (in funds which are immediately available on the due date for such payment)
sufficient to pay such principal, premium, if any, or interest, and (unless such
paying agent is the Trustee) the Company will promptly notify the Trustee of any
failure to take such action; PROVIDED that if such deposit is made on the due
date, such deposit shall be received by the paying agent by 10:00 a.m. New York
City time, on such date.

         (b) If the Company shall act as its own paying agent, it will, on or
before each due date of the principal of, premium, if any, or interest on the
Debentures, set aside, segregate and hold in trust for the benefit of the
holders of the Debentures a sum sufficient to pay such principal, premium, if
any, or interest so becoming due and will promptly notify the Trustee of any
failure to take such action and of any failure by the Company (or any other
obligor under the Debentures) to make any payment of the principal of, premium,
if any, or interest on the Debentures when the same shall become due and
payable.

         (c) Anything in this Section 5.04 to the contrary notwithstanding, the
Company may, at any time, for the purpose of obtaining a satisfaction and
discharge of this Indenture, or for any other reason, pay or cause to be paid to
the Trustee all sums held in trust by the Company or any paying agent hereunder
as required by this Section 5.04, such sums to be held by the Trustee upon the
trusts herein contained and upon such payment by the Company or any paying agent
to the Trustee, the Company or such paying agent shall be released from all
further liability with respect to such sums.


                                       33
<Page>

         (d) Anything in this Section 5.04 to the contrary notwithstanding, the
agreement to hold sums in trust as provided in this Section 5.04 is subject to
Sections 13.03 and 13.04.

         The Trustee shall not be responsible for the actions of any other
paying agents (including the Company if acting as its own paying agent) and
shall have no control of any funds held by such other paying agents.

         Section 5.05. EXISTENCE. Subject to Article 12, the Company will do or
cause to be done all things necessary to preserve and keep in full force and
effect its existence and rights (charter and statutory); PROVIDED that the
Company shall not be required to preserve any such right if the Company shall
determine that the preservation thereof is no longer desirable in the conduct of
the business of the Company and that the loss thereof is not disadvantageous in
any material respect to the Debentureholders.

         Section 5.06. MAINTENANCE OF PROPERTIES. The Company will cause all
properties used or useful in the conduct of its business or the business of any
Significant Subsidiary to be maintained and kept in good condition, repair and
working order and supplied with all necessary equipment and will cause to be
made all necessary repairs, renewals, replacements, betterments and improvements
thereof, all as in the judgment of the Company may be necessary so that the
business carried on in connection therewith may be properly and advantageously
conducted at all times; PROVIDED that nothing in this Section shall prevent the
Company from discontinuing the operation or maintenance of any of such
properties if such discontinuance is, in the judgment of the Company, desirable
in the conduct of its business or the business of any subsidiary and not
disadvantageous in any material respect to the Debentureholders.

         Section 5.07. PAYMENT OF TAXES AND OTHER CLAIMS. The Company will pay
or discharge, or cause to be paid or discharged, before the same may become
delinquent, (i) all taxes, assessments and governmental charges levied or
imposed upon the Company or any Significant Subsidiary or upon the income,
profits or property of the Company or any Significant Subsidiary, (ii) all
claims for labor, materials and supplies which, if unpaid, might by law become a
lien or charge upon the property of the Company or any Significant Subsidiary
and (iii) all stamp taxes and other duties, if any, which may be imposed by the
United States or any political subdivision thereof or therein in connection with
the issuance, transfer, exchange, conversion, redemption or repurchase of any
Debentures or with respect to this Indenture; PROVIDED that, in the case of
clauses (i) and (ii), the Company shall not be required to pay or discharge or
cause to be paid or discharged any such tax, assessment, charge or claim (A) if
the failure to do so will not, in the aggregate, have a material adverse impact
on the Company, or (B) if the amount, applicability or validity is being
contested in good faith by appropriate proceedings.


                                       34
<Page>

         Section 5.08. RULE 144A INFORMATION REQUIREMENT. Within the period
prior to the expiration of the holding period applicable to sales thereof under
Rule 144(k) under the Securities Act (or any successor provision), the Company
covenants and agrees that it shall, during any period in which it is not subject
to Section 13 or 15(d) under the Exchange Act, make available to any holder or
beneficial holder of Debentures or any Common Stock issued upon conversion
thereof which continue to be Restricted Securities in connection with any sale
thereof and any prospective purchaser of Debentures or such Common Stock
designated by such holder or beneficial holder, the information required
pursuant to Rule 144A(d)(4) under the Securities Act upon the request of any
holder or beneficial holder of the Debentures or such Common Stock and it will
take such further action as any holder or beneficial holder of such Debentures
or such Common Stock may reasonably request, all to the extent required from
time to time to enable such holder or beneficial holder to sell its Debentures
or Common Stock without registration under the Securities Act within the
limitation of the exemption provided by Rule 144A, as such Rule may be amended
from time to time. Upon the request of any holder or any beneficial holder of
the Debentures or such Common Stock, the Company will deliver to such holder a
written statement as to whether it has complied with such requirements.

         Section 5.09. STAY, EXTENSION AND USURY LAWS. The Company covenants (to
the extent that it may lawfully do so) that it shall 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 or other law which would prohibit or
forgive the Company from paying all or any portion of the principal of, premium,
if any, or interest on the Debentures as contemplated herein, wherever enacted,
now or at any time hereafter in force, or which may affect the covenants or the
performance of this Indenture and the Company (to the extent 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 had been enacted.

         Section 5.10. COMPLIANCE CERTIFICATE. The Company shall deliver to the
Trustee, within one hundred twenty (120) days after the end of each fiscal year
of the Company, a certificate signed by either the principal executive officer,
principal financial officer or principal accounting officer of the Company,
stating whether or not to the best knowledge of the signer thereof the Company
is in default in the performance and observance of any of the terms, provisions
and conditions of this Indenture (without regard to any period of grace or
requirement of notice provided hereunder) and, if the Company shall be in
default, specifying all such defaults and the nature and the status thereof of
which the signer may have knowledge.

         The Company will deliver to the Trustee, forthwith upon becoming aware
of (i) any default in the performance or observance of any covenant, agreement
or condition contained in this Indenture, or (ii) any Event of Default, an
Officers'


                                       35
<Page>

Certificate specifying with particularity such default or Event of Default and
further stating what action the Company has taken, is taking or proposes to take
with respect thereto.

         Any notice required to be given under this Section 5.10 shall be
delivered to a Responsible Officer of the Trustee at its Corporate Trust Office.

         Section 5.11. LIQUIDATED DAMAGES NOTICE. In the event that the Company
is required to pay Liquidated Damages to holders of Debentures pursuant to the
Registration Rights Agreement, the Company will provide written notice
("LIQUIDATED DAMAGES NOTICE") to the Trustee of its obligation to pay Liquidated
Damages no later than fifteen (15) days prior to the proposed payment date for
the Liquidated Damages, and the Liquidated Damages Notice shall set forth the
amount of Liquidated Damages to be paid by the Company on such payment date. The
Trustee shall not at any time be under any duty or responsibility to any holder
of Debentures to determine the Liquidated Damages, or with respect to the
nature, extent or calculation of the amount of Liquidated Damages when made, or
with respect to the method employed in such calculation of the Liquidated
Damages.

         Section 5.12. CONTINGENT DEBT TAX TREATMENT. The Company agrees, and by
acceptance of a Debenture, each holder hereof is deemed to have agreed, with
respect to each of the matters set forth in (a) and (b) below, as follows:

         (a) Tax Treatment:

                  (i) to treat the Debentures as indebtedness of the Company for
         all tax purposes;

                  (ii) to treat the Debentures as indebtedness that are subject
         to the special regulations governing contingent payment debt
         instruments that are contained in U.S. Treasury Regulation section
         1.1275-4; and

                  (iii) to treat any payment to and receipt by a holder of
         Common Stock upon conversion of a Debenture as a contingent payment
         under U.S. Treasury Regulation section 1.1275-4(b) that will result in
         an adjustment under U.S. Treasury Regulation section 1.1275-4(b)(3)(iv)
         and U.S. Treasury Regulation section 1.1275-4(b)(6).

         (b) Comparable Yield and Projected Payment Schedule. Solely for
purposes of applying U.S. Treasury Regulation section 1.1275-4 to the
Debentures:

                  (i) for United States Federal Income tax purposes, the Company
         shall accrue interest with respect to outstanding Debentures as
         original issue discount according to the "noncontingent bond method,"
         as set forth in U.S. Treasury Regulation section 1.1275-4(b);


                                       36
<Page>

                  (ii) the Company has determined that the comparable yield, as
         defined in U.S. Treasury Regulation section 1.1275-4(b)(4)(i), for the
         Debentures is 9.1%, compounded semiannually;

                  (iii) the Company has determined that the projected payment
         schedule, as defined in U.S. Treasury Regulation section
         1.1275-4(b)(ii), for the Debentures consists of the projected payment
         schedule referred to in (v) below;

                  (iv) the Company acknowledges and agrees, and each holder and
         any beneficial holder of the Debenture, by its purchase of a Debenture
         shall be deemed to acknowledge and agree that (A) the projected payment
         schedule is determined on a basis of an assumption of linear growth of
         stock price and a constant dividend yield, (B) the comparable yield and
         the projected payment schedule are not determined for any purpose other
         than for the purpose of applying U.S. Treasury Regulation section
         1.1275-4(b) to the Debentures and (C) the comparable yield and the
         projected payment schedule do not constitute a projection or
         representation regarding the actual amounts payable on the Debentures;
         and

                  (v) the projected payment schedule, as defined in U.S.
         Treasury Regulation section 1.1275-4(b)(4)(ii) for the Debentures is
         set forth in Annex 1 hereto.

         Section 5.13. CALCULATION OF ORIGINAL ISSUE DISCOUNT. The Company shall
file with the Trustee promptly at the end of each calendar year (i) a written
notice specifying the amount of original issue discount (including daily rates
and accrual periods) accrued on outstanding Debentures as of the end of such
year and (ii) such other specific information relating to such original issue
discount as may then be relevant under the Internal Revenue Code of 1986, as
amended from time to time.



                                    ARTICLE 6
       DEBENTUREHOLDERS' LISTS AND REPORTS BY THE COMPANY AND THE TRUSTEE

         Section 6.01. DEBENTUREHOLDERS' LISTS. The Company covenants and agrees
that it will furnish or cause to be furnished to the Trustee, semiannually, not
more than fifteen (15) days after each June 1 and December 1 in each year
beginning with December 1, 2002, and at such other times as the Trustee may
request in writing, within thirty (30) days after receipt by the Company of any
such request (or such lesser time as the Trustee may reasonably request in order
to enable it to timely provide any notice to be provided by it hereunder), a
list in such form as the Trustee may reasonably require of the names and
addresses of the holders of Debentures as of a date not more than fifteen (15)
days (or such other date as the Trustee may reasonably request in order to so
provide any such notices) prior to the time such information is furnished,
except that no such list


                                       37
<Page>

need be furnished by the Company to the Trustee so long as the Trustee is acting
as the sole Debenture registrar.

         Section 6.02. PRESERVATION AND DISCLOSURE OF LISTS. (a) The Trustee
shall preserve, in as current a form as is reasonably practicable, all
information as to the names and addresses of the holders of Debentures contained
in the most recent list furnished to it as provided in Section 6.01 or
maintained by the Trustee in its capacity as Debenture registrar or co-registrar
in respect of the Debentures, if so acting. The Trustee may destroy any list
furnished to it as provided in Section 6.01 upon receipt of a new list so
furnished.

         (b) The rights of Debentureholders to communicate with other holders of
Debentures with respect to their rights under this Indenture or under the
Debentures, and the corresponding rights and duties of the Trustee, shall be as
provided by the Trust Indenture Act.

         (c) Every Debentureholder, by receiving and holding the same, agrees
with the Company and the Trustee that neither the Company nor the Trustee nor
any agent of either of them shall be held accountable by reason of any
disclosure of information as to names and addresses of holders of Debentures
made pursuant to the Trust Indenture Act.

         Section 6.03. REPORTS BY TRUSTEE. (a) Within sixty (60) days after
December 15 of each year commencing with the year 2003, the Trustee shall
transmit to holders of Debentures such reports dated as of December 15 of the
year in which such reports are made concerning the Trustee and its actions under
this Indenture as may be required pursuant to the Trust Indenture Act at the
times and in the manner provided pursuant thereto.

         (b) A copy of such report shall, at the time of such transmission to
holders of Debentures, be filed by the Trustee with each stock exchange and
automated quotation system upon which the Debentures are listed and with the
Company. The Company will promptly notify the Trustee in writing when the
Debentures are listed on any stock exchange or automated quotation system or
delisted therefrom.

         Section 6.04. REPORTS BY COMPANY. The Company shall file with the
Trustee (and the Commission if at any time after the Indenture becomes qualified
under the Trust Indenture Act), and transmit to holders of Debentures, such
information, documents and other reports and such summaries thereof, as may be
required pursuant to the Trust Indenture Act at the times and in the manner
provided pursuant to such Act, whether or not the Debentures are governed by
such Act; PROVIDED that any such information, documents or reports required to
be filed with the Commission pursuant to Section 13 or 15(d) of the Exchange Act
shall be filed with the Trustee within fifteen (15) days after the same is so
required to be filed with the Commission. Delivery of such reports, information
and documents to the Trustee is for informational purposes only and the
Trustee's


                                       38
<Page>

receipt of such shall not constitute constructive notice of any information
contained therein or determinable from information contained therein, including
the Company's compliance with any of its covenants hereunder (as to which the
Trustee is entitled to rely exclusively on an Officers' Certificates).



                                    ARTICLE 7
       REMEDIES OF THE TRUSTEE AND DEBENTUREHOLDERS ON AN EVENT OF DEFAULT

         Section 7.01. EVENTS OF DEFAULT. In case one or more of the following
Events of Default (whatever the reason for such Event of Default and whether it
shall be voluntary or involuntary or be effected by operation of law or pursuant
to any judgment, decree or order of any court or any order, rule or regulation
of any administrative or governmental body) shall have occurred and be
continuing:

         (a) default in the payment of any installment of interest upon any of
the Debentures as and when the same shall become due and payable, and
continuance of such default for a period of thirty (30) days; or

         (b) default in the payment of the principal of or premium, if any, on
any of the Debentures as and when the same shall become due and payable either
at maturity or in connection with any redemption, repurchase or otherwise, in
each case pursuant to Article 3, by acceleration or otherwise; or

         (c) default in the Company's obligation to provide a Fundamental Change
Notice upon a Fundamental Change as provided in Section 3.05; or

         (d) failure on the part of the Company duly to observe or perform any
other of the covenants or agreements on the part of the Company in the
Debentures or in this Indenture (other than a covenant or agreement a default in
whose performance or whose breach is elsewhere in this Section 7.01 specifically
dealt with) continued for a period of ninety (90) days after the date on which
written notice of such failure, requiring the Company to remedy the same, shall
have been given to the Company by the Trustee, or the Company and a Responsible
Officer of the Trustee by the holders of at least twenty-five percent (25%) in
aggregate principal amount of the Debentures at the time outstanding determined
in accordance with Section 9.04; or

         (e) the Company shall commence a voluntary case or other proceeding
seeking liquidation, reorganization or other relief with respect to the Company
or its debts under any bankruptcy, insolvency or other similar law now or
hereafter in effect or seeking the appointment of a trustee, receiver,
liquidator, custodian or other similar official of the Company or any
substantial part of the property of the Company, or shall consent to any such
relief or to the appointment of or taking possession by any such official in an
involuntary case or other proceeding


                                       39
<Page>

commenced against the Company, or shall make a general assignment for the
benefit of creditors, or shall fail generally to pay its debts as they become
due; or

         (f) an involuntary case or other proceeding shall be commenced against
the Company seeking liquidation, reorganization or other relief with respect to
the Company or its debts under any bankruptcy, insolvency or other similar law
now or hereafter in effect or seeking the appointment of a trustee, receiver,
liquidator, custodian or other similar official of the Company or any
substantial part of the property of the Company, and such involuntary case or
other proceeding shall remain undismissed and unstayed for a period of ninety
(90) consecutive days;

then, and in each and every such case (other than an Event of Default specified
in Section 7.01(e) or 7.01(f)), unless the principal of all of the Debentures
shall have already become due and payable, either the Trustee or the holders of
not less than twenty-five percent (25%) in aggregate principal amount of the
Debentures then outstanding hereunder determined in accordance with Section
9.04, by notice in writing to the Company (and to the Trustee if given by
Debentureholders), may declare the principal of and premium, if any, on all the
Debentures and the interest accrued thereon to be due and payable immediately,
and upon any such declaration the same shall become and shall be immediately due
and payable, anything in this Indenture or in the Debentures contained to the
contrary notwithstanding. If an Event of Default specified in Section 7.01(e) or
7.01(f) occurs, the principal of all the Debentures and the interest accrued
thereon shall be immediately and automatically due and payable without necessity
of further action. This provision, however, is subject to the conditions that
if, at any time after the principal of the Debentures shall have been so
declared due and payable, and before any judgment or decree for the payment of
the monies due shall have been obtained or entered as hereinafter provided, the
Company shall pay or shall deposit with the Trustee a sum sufficient to pay all
matured installments of interest upon all Debentures and the principal of and
premium, if any, on any and all Debentures which shall have become due otherwise
than by acceleration (with interest on overdue installments of interest (to the
extent that payment of such interest is enforceable under applicable law) and on
such principal and premium, if any, at the rate borne by the Debentures, to the
date of such payment or deposit) and amounts due to the Trustee pursuant to
Section 8.06, and if any and all defaults under this Indenture, other than the
nonpayment of principal of and premium, if any, and accrued interest on
Debentures which shall have become due by acceleration, shall have been cured or
waived pursuant to Section 7.07, then and in every such case the holders of a
majority in aggregate principal amount of the Debentures then outstanding, by
written notice to the Company and to the Trustee, may waive all defaults or
Events of Default and rescind and annul such declaration and its consequences;
but no such waiver or rescission and annulment shall extend to or shall affect
any subsequent default or Event of Default, or shall impair any right consequent
thereon. The Company shall notify in writing a Responsible Officer of the
Trustee, promptly upon becoming aware thereof, of any Event of Default.


                                       40
<Page>

         In case the Trustee shall have proceeded to enforce any right under
this Indenture and such proceedings shall have been discontinued or abandoned
because of such waiver or rescission and annulment or for any other reason or
shall have been determined adversely to the Trustee, then and in every such case
the Company, the holders of Debentures, and the Trustee shall be restored
respectively to their several positions and rights hereunder, and all rights,
remedies and powers of the Company, the holders of Debentures, and the Trustee
shall continue as though no such proceeding had been taken.

         Section 7.02. PAYMENTS OF DEBENTURES ON DEFAULT; SUIT THEREFOR. The
Company covenants that (a) in case default shall be made in the payment of any
installment of interest upon any of the Debentures as and when the same shall
become due and payable, and such default shall have continued for a period of
thirty (30) days, or (b) in case default shall be made in the payment of the
principal of or premium, if any, on any of the Debentures as and when the same
shall have become due and payable, whether at maturity of the Debentures or in
connection with any redemption, by or under this Indenture declaration or
otherwise, then, upon demand of the Trustee, the Company will pay to the
Trustee, for the benefit of the holders of the Debentures, the whole amount that
then shall have become due and payable on all such Debentures for principal and
premium, if any, or interest, as the case may be, with interest upon the overdue
principal and premium, if any, and (to the extent that payment of such interest
is enforceable under applicable law) upon the overdue installments of interest
at the rate borne by the Debentures, plus 1% and, in addition thereto, such
further amount as shall be sufficient to cover the costs and expenses of
collection, including reasonable compensation to the Trustee, its agents,
attorneys and counsel, and all other amounts due the Trustee under Section 8.06.
Until such demand by the Trustee, the Company may pay the principal of and
premium, if any, and interest on the Debentures to the registered holders,
whether or not the Debentures are overdue.

         In case the Company shall fail forthwith to pay such amounts upon such
demand, the Trustee, in its own name and as trustee of an express trust, shall
be entitled and empowered to institute any actions or proceedings at law or in
equity for the collection of the sums so due and unpaid, and may prosecute any
such action or proceeding to judgment or final decree, and may enforce any such
judgment or final decree against the Company or any other obligor on the
Debentures and collect in the manner provided by law out of the property of the
Company or any other obligor on the Debentures wherever situated the monies
adjudged or decreed to be payable.

         In case there shall be pending proceedings for the bankruptcy or for
the reorganization of the Company or any other obligor on the Debentures under
Title 11 of the United States Code, or any other applicable law, or in case a
receiver, assignee or trustee in bankruptcy or reorganization, liquidator,
sequestrator or similar official shall have been appointed for or taken
possession of the Company or such other obligor, the property of the Company or
such other obligor, or in the


                                       41
<Page>

case of any other judicial proceedings relative to the Company or such other
obligor upon the Debentures, or to the creditors or property of the Company or
such other obligor, the Trustee, irrespective of whether the principal of the
Debentures shall then be due and payable as therein expressed or by declaration
or otherwise and irrespective of whether the Trustee shall have made any demand
pursuant to the provisions of this Section 7.02, shall be entitled and
empowered, by intervention in such proceedings or otherwise, to file and prove a
claim or claims for the whole amount of principal, premium, if any, and interest
owing and unpaid in respect of the Debentures, and, in case of any judicial
proceedings, to 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 and of the
Debentureholders allowed in such judicial proceedings relative to the Company or
any other obligor on the Debentures, its or their creditors, or its or their
property, and to collect and receive any monies or other property payable or
deliverable on any such claims, and to distribute the same after the deduction
of any amounts due the Trustee under Section 8.06, and any receiver, assignee or
trustee in bankruptcy or reorganization, liquidator, custodian or similar
official is hereby authorized by each of the Debentureholders to make such
payments to the Trustee, and, in the event that the Trustee shall consent to the
making of such payments directly to the Debentureholders, to pay to the Trustee
any amount due it for reasonable compensation, expenses, advances and
disbursements, including counsel fees and expenses incurred by it up to the date
of such distribution. To the extent that such payment of reasonable
compensation, expenses, advances and disbursements out of the estate in any such
proceedings shall be denied for any reason, payment of the same shall be secured
by a lien on, and shall be paid out of, any and all distributions, dividends,
monies, securities and other property which the holders of the Debentures may be
entitled to receive in such proceedings, whether in liquidation or under any
plan of reorganization or arrangement or otherwise.

         All rights of action and of asserting claims under this Indenture, or
under any of the Debentures, may be enforced by the Trustee without the
possession of any of the Debentures, or the production thereof at any trial or
other proceeding relative thereto, and any such suit or proceeding instituted by
the Trustee shall be brought in its own name as trustee of an express trust, and
any recovery of judgment shall, after provision for the payment of the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel, be for the ratable benefit of the holders of the
Debentures.

         In any proceedings brought by the Trustee (and in any proceedings
involving the interpretation of any provision of this Indenture to which the
Trustee shall be a party) the Trustee shall be held to represent all the holders
of the Debentures, and it shall not be necessary to make any holders of the
Debentures parties to any such proceedings.

         Section 7.03. APPLICATION OF MONIES COLLECTED BY TRUSTEE. Any monies
collected by the Trustee pursuant to this Article 7 shall be applied in the
order following, at the date or dates fixed by the Trustee for the distribution
of such


                                       42
<Page>

monies, upon presentation of the several Debentures, and stamping thereon the
payment, if only partially paid, and upon surrender thereof, if fully paid:

         FIRST: To the payment of all amounts due the Trustee under
Section 8.06;

         SECOND: In case the principal of the outstanding Debentures shall not
have become due and be unpaid, to the payment of interest on the Debentures in
default in the order of the maturity of the installments of such interest, with
interest (to the extent that such interest has been collected by the Trustee)
upon the overdue installments of interest at the rate borne by the Debentures,
such payments to be made ratably to the Persons entitled thereto;

         THIRD: In case the principal of the outstanding Debentures shall have
become due, by declaration or otherwise, and be unpaid to the payment of the
whole amount then owing and unpaid upon the Debentures for principal and
premium, if any, and interest, with interest on the overdue principal and
premium, if any, and (to the extent that such interest has been collected by the
Trustee) upon overdue installments of interest at the rate borne by the
Debentures, and in case such monies shall be insufficient to pay in full the
whole amounts so due and unpaid upon the Debentures, then to the payment of such
principal and premium, if any, and interest without preference or priority of
principal and premium, if any, over interest, or of interest over principal and
premium, if any, or of any installment of interest over any other installment of
interest, or of any Debenture over any other Debenture, ratably to the aggregate
of such principal and premium, if any, and accrued and unpaid interest; and

         FOURTH: To the payment of the remainder, if any, to the Company or any
other Person lawfully entitled thereto.

         Section 7.04. PROCEEDINGS BY DEBENTUREHOLDER. No holder of any
Debenture shall have any right by virtue of or by reference to any provision of
this Indenture to institute any suit, action or proceeding in equity or at law
upon or under or with respect to this Indenture, or for the appointment of a
receiver, trustee, liquidator, custodian or other similar official, or for any
other remedy hereunder, unless such holder previously shall have given to the
Trustee written notice of an Event of Default and of the continuance thereof, as
hereinbefore provided, and unless also the holders of not less than twenty-five
percent (25%) in aggregate principal amount of the Debentures then outstanding
shall have made written request upon the Trustee to institute such action, suit
or proceeding in its own name as Trustee hereunder and shall have offered to the
Trustee such reasonable security or indemnity as it may require against the
costs, expenses and liabilities to be incurred therein or thereby, and the
Trustee for sixty (60) days after its receipt of such notice, request and offer
of indemnity, shall have neglected or refused to institute any such action, suit
or proceeding and no direction inconsistent with such written request shall have
been given to the Trustee pursuant to Section 7.07; it being understood and
intended, and being expressly covenanted by the taker and holder of every
Debenture with every other


                                       43
<Page>

taker and holder and the Trustee, that no one or more holders of Debentures
shall have any right in any manner whatever by virtue of or by reference to any
provision of this Indenture to affect, disturb or prejudice the rights of any
other holder of Debentures, or to obtain or seek to obtain priority over or
preference to any other such holder, or to enforce any right under this
Indenture, except in the manner herein provided and for the equal, ratable and
common benefit of all holders of Debentures (except as otherwise provided
herein). For the protection and enforcement of this Section 7.04, each and every
Debentureholder and the Trustee shall be entitled to such relief as can be given
either at law or in equity.

         Notwithstanding any other provision of this Indenture and any provision
of any Debenture, the right of any holder of any Debenture to receive payment of
the principal of and premium, if any (including the redemption price upon
redemption pursuant to Article 7), and accrued interest on such Debenture, on or
after the respective due dates expressed in such Debenture or in the event of
redemption, or to institute suit for the enforcement of any such payment on or
after such respective dates against the Company shall not be impaired or
affected without the consent of such holder.

         Anything in this Indenture or the Debentures to the contrary
notwithstanding, the holder of any Debenture, without the consent of either the
Trustee or the holder of any other Debenture, in its own behalf and for its own
benefit, may enforce, and may institute and maintain any proceeding suitable to
enforce, its rights of conversion as provided herein.

         Section 7.05. PROCEEDINGS BY TRUSTEE. In case of an Event of Default,
the Trustee may, in its discretion, proceed to protect and enforce the rights
vested in it by this Indenture by such appropriate judicial proceedings as are
necessary to protect and enforce any of such rights, either by suit in equity or
by action at law or by proceeding in bankruptcy or otherwise, whether for the
specific enforcement of any covenant or agreement contained in this Indenture or
in aid of the exercise of any power granted in this Indenture, or to enforce any
other legal or equitable right vested in the Trustee by this Indenture or by
law.

         Section 7.06. REMEDIES CUMULATIVE AND CONTINUING. Except as provided in
Section 2.06, all powers and remedies given by this Article 7 to the Trustee or
to the Debentureholders shall, to the extent permitted by law, be deemed
cumulative and not exclusive of any thereof or of any other powers and remedies
available to the Trustee or the holders of the Debentures, by judicial
proceedings or otherwise, to enforce the performance or observance of the
covenants and agreements contained in this Indenture, and no delay or omission
of the Trustee or of any holder of any of the Debentures to exercise any right
or power accruing upon any default or Event of Default occurring and continuing
as aforesaid shall impair any such right or power, or shall be construed to be a
waiver of any such default or any acquiescence therein, and, subject to the
provisions of Section 7.04, every power and remedy given by this Article 7 or by
law to the Trustee or to the


                                       44
<Page>

Debentureholders may be exercised from time to time, and as often as shall be
deemed expedient, by the Trustee or by the Debentureholders.

         Section 7.07. DIRECTION OF PROCEEDINGS AND WAIVER OF DEFAULTS BY
MAJORITY OF DEBENTUREHOLDERS. The holders of a majority in aggregate principal
amount of the Debentures at the time outstanding determined in accordance with
Section 9.04 shall have the right to 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 the Trustee; PROVIDED that (a) such direction
shall not be in conflict with any rule of law or with this Indenture, (b) the
Trustee may take any other action which is not inconsistent with such direction
and (c) the Trustee may decline to take any action that would benefit some
Debentureholder to the detriment of other Debentureholders. The holders of a
majority in aggregate principal amount of the Debentures at the time outstanding
determined in accordance with Section 9.04 may, on behalf of the holders of all
of the Debentures, waive any past default or Event of Default hereunder and its
consequences except (i) a default in the payment of interest or premium, if any,
on, or the principal of, the Debentures, (ii) a failure by the Company to
convert any Debentures into Common Stock, (iii) a default in the payment of the
redemption price pursuant to Article 3, (iv) a default in the payment of the
purchase price pursuant to Article 3 or (v) a default in respect of a covenant
or provisions hereof which under Article 11 cannot be modified or amended
without the consent of the holders of each or all Debentures then outstanding or
affected thereby. Upon any such waiver, the Company, the Trustee and the holders
of the Debentures shall be restored to their former positions and rights
hereunder; but no such waiver shall extend to any subsequent or other default or
Event of Default or impair any right consequent thereon. Whenever any default or
Event of Default hereunder shall have been waived as permitted by this Section
7.07, said default or Event of Default shall for all purposes of the Debentures
and this Indenture be deemed to have been cured and to be not continuing; but no
such waiver shall extend to any subsequent or other default or Event of Default
or impair any right consequent thereon.

         Section 7.08. NOTICE OF DEFAULTS. The Trustee shall, within ninety (90)
days after a Responsible Officer of the Trustee has knowledge of the occurrence
of a default, mail to all Debentureholders, as the names and addresses of such
holders appear upon the Debenture register, notice of all defaults known to a
Responsible Officer, unless such defaults shall have been cured or waived before
the giving of such notice; PROVIDED that except in the case of default in the
payment of the principal of, or premium, if any, or interest on any of the
Debentures, the Trustee shall be protected in withholding such notice if and so
long as a trust committee of directors and/or Responsible Officers of the
Trustee in good faith determines that the withholding of such notice is in the
interests of the Debentureholders.

         Section 7.09. UNDERTAKING TO PAY COSTS. All parties to this Indenture
agree, and each holder of any Debenture by his acceptance thereof shall be


                                       45
<Page>

deemed to have agreed, that any court may, in its discretion, require, 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, the
filing by any party litigant in such suit of an undertaking to pay the costs of
such suit and that such court may in its discretion assess reasonable costs,
including reasonable attorneys' fees and expenses, against any party litigant in
such suit, having due regard to the merits and good faith of the claims or
defenses made by such party litigant; PROVIDED that the provisions of this
Section 7.09 (to the extent permitted by law) shall not apply to any suit
instituted by the Trustee, to any suit instituted by any Debentureholder, or
group of Debentureholders, holding in the aggregate more than ten percent in
principal amount of the Debentures at the time outstanding determined in
accordance with Section 9.04, or to any suit instituted by any Debentureholder
for the enforcement of the payment of the principal of or premium, if any, or
interest on any Debenture on or after the due date expressed in such Debenture
or to any suit for the enforcement of the right to convert any Debenture in
accordance with the provisions of Article 15.



                                    ARTICLE 8
                                   THE TRUSTEE

         Section 8.01. DUTIES AND RESPONSIBILITIES OF TRUSTEE. The Trustee,
prior to the occurrence of an Event of Default and after the curing of all
Events of Default which may have occurred, undertakes to perform such duties and
only such duties as are specifically set forth in this Indenture. In case an
Event of Default has occurred (which has not been cured or waived), 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 own affairs.

         No provision of this Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act or its own willful misconduct, except that:

         (a) prior to the occurrence of an Event of Default and after the curing
or waiving of all Events of Default which may have occurred:

                      (i) the duties and obligations of the Trustee shall be
         determined solely by the express provisions of this Indenture and the
         Trust Indenture Act, and the Trustee shall not be liable except for the
         performance of such duties and obligations as are specifically set
         forth in this Indenture and no implied covenants or obligations shall
         be read into this Indenture and the Trust Indenture Act against the
         Trustee; and

                      (ii) in the absence of bad faith and willful misconduct on
         the part of the Trustee, the Trustee may conclusively rely as to the
         truth of the statements and the correctness of the opinions expressed
         therein, upon any


                                       46
<Page>

         certificates or opinions furnished to the Trustee and conforming to the
         requirements of this Indenture; but, in the case of any such
         certificates or opinions which by any provisions hereof are
         specifically required to be furnished to the Trustee, the Trustee shall
         be under a duty to examine the same to determine whether or not they
         conform to the requirements of this Indenture;

         (b) the Trustee shall not be liable for any error of judgment made in
good faith by a Responsible Officer or Officers of the Trustee, unless the
Trustee was negligent in ascertaining the pertinent facts;

         (c) the Trustee shall not be liable with respect to any action taken or
omitted to be taken by it in good faith in accordance with the written direction
of the holders of not less than a majority in principal amount of the Debentures
at the time outstanding determined as provided in Section 9.04 relating to the
time, method and place of conducting any proceeding for any remedy available to
the Trustee, or exercising any trust or power conferred upon the Trustee, under
this Indenture;

         (d) whether or not therein 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 Section;

         (e) the Trustee shall not be liable in respect of any payment (as to
the correctness of amount, entitlement to receive or any other matters relating
to payment) or notice effected by the Company or any paying agent or any records
maintained by any co-registrar with respect to the Debentures;

         (f) if any party fails to deliver a notice relating to an event the
fact of which, pursuant to this Indenture, requires notice to be sent to the
Trustee, the Trustee may conclusively rely on its failure to receive such notice
as reason to act as if no such event occurred; and

         (g) the Trustee shall not be deemed to have knowledge of any Event of
Default hereunder unless it shall have been notified in writing of such Event of
Default by the Company or the holders of at least 10% in aggregate principal
amount of the Debentures.

         None of the provisions contained in this Indenture shall require the
Trustee to expend or risk its own funds or otherwise incur personal financial
liability in the performance of any of its duties or in the exercise of any of
its rights or powers, if there is reasonable ground for believing that the
repayment of such funds or adequate indemnity against such risk or liability is
not reasonably assured to it.

         Section 8.02. RELIANCE ON DOCUMENTS, OPINIONS, ETC. Except as otherwise
provided in Section 8.01:


                                       47
<Page>

         (a) the Trustee may conclusively rely and shall be protected in acting
upon any resolution, certificate, statement, instrument, opinion, report,
notice, request, consent, order, bond, debenture, note, coupon or other paper or
document (whether in its original or facsimile form) believed by it in good
faith to be genuine and to have been signed or presented by the proper party or
parties;

         (b) any request, direction, order or demand of the Company mentioned
herein shall be sufficiently evidenced by an Officers' Certificate (unless other
evidence in respect thereof be herein specifically prescribed); and any
resolution of the Board of Directors may be evidenced to the Trustee by a copy
thereof certified by the Secretary or an Assistant Secretary of the Company;

         (c) the Trustee may consult with counsel of its own selection and any
advice or Opinion of Counsel shall be full and complete authorization and
protection in respect of any action taken or omitted by it hereunder in good
faith and in accordance with such advice or Opinion of Counsel;

         (d) the Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request, order or
direction of any of the Debentureholders pursuant to the provisions of this
Indenture, unless such Debentureholders shall have offered to the Trustee
reasonable security or indemnity satisfactory to it against the costs, expenses
and liabilities which may be incurred therein or thereby;

         (e) the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture or
other paper or document, but the Trustee may make such further inquiry or
investigation into such facts or matters as it may see fit, and, if 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; and

         (f) the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed by it with due care
hereunder.

         (g) the Trustee shall not be liable for any action taken, suffered or
omitted to be taken by it in good faith and reasonably believed by it to be
authorized or within the discretion or rights or powers conferred upon it by
this Indenture;

         (h) the rights, privileges, protections, immunities and benefits given
to the Trustee, including, without limitation, its right to be indemnified, are
extended to, and shall be enforceable by, the Trustee in each of its capacities
hereunder, and each agent, custodian and other Person employed to act hereunder;
and


                                       48
<Page>

         (i) the Trustee may request that the Company deliver an Officers'
Certificate setting forth the names of individuals and/or titles of officers
authorized at such time to take specified actions pursuant to this Indenture,
which Officers' Certificate may be signed by any person authorized to sign an
Officers' Certificate, including any person specified as so authorized in any
such certificate previously delivered and not superseded.

         Section 8.03. NO RESPONSIBILITY FOR RECITALS, ETC. The recitals
contained herein and in the Debentures (except in the Trustee's certificate of
authentication) shall be taken as the statements of the Company, and the Trustee
assumes no responsibility for the correctness of the same. The Trustee makes no
representations as to the validity or sufficiency of this Indenture or of the
Debentures. The Trustee shall not be accountable for the use or application by
the Company of any Debentures or the proceeds of any Debentures authenticated
and delivered by the Trustee in conformity with the provisions of this
Indenture.

         Section 8.04. TRUSTEE, PAYING AGENTS, CONVERSION AGENTS OR REGISTRAR
MAY OWN DEBENTURES. The Trustee, any paying agent, any conversion agent or
Debenture registrar, in its individual or any other capacity, may become the
owner or pledgee of Debentures with the same rights it would have if it were not
Trustee, paying agent, conversion agent or Debenture registrar.

         Section 8.05. MONIES TO BE HELD IN TRUST. Subject to the provisions of
Section 13.04, all monies received by the Trustee shall, until used or applied
as herein provided, be held in trust for the purposes for which they were
received. Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law. The Trustee shall be
under no liability for interest on any money received by it hereunder except as
may be agreed in writing from time to time by the Company and the Trustee.

         Section 8.06. COMPENSATION AND EXPENSES OF TRUSTEE. The Company
covenants and agrees to pay to the Trustee from time to time, and the Trustee
shall be entitled to, such compensation for all services rendered by it
hereunder in any capacity (which shall not be limited by any provision of law in
regard to the compensation of a trustee of an express trust) as mutually agreed
to from time to time in writing between the Company and the Trustee, and the
Company will pay or reimburse the Trustee upon its request for all reasonable
expenses, disbursements and advances reasonably incurred or made by the Trustee
in accordance with any of the provisions of this Indenture (including the
reasonable compensation and the expenses and disbursements of its counsel and of
all Persons not regularly in its employ) except any such expense, disbursement
or advance as may arise from its negligence, willful misconduct, recklessness or
bad faith. The Company also covenants to indemnify the Trustee and any
predecessor Trustee (or any officer, director or employee of the Trustee), in
any capacity under this Indenture and its agents and any authenticating agent
for, and to hold them harmless against, any and all loss, liability, damage,
claim or expense including taxes (other than taxes based on the income of the
Trustee) incurred


                                       49
<Page>

without negligence, willful misconduct, recklessness or bad faith on the part of
the Trustee or such officers, directors, employees and agent or authenticating
agent, as the case may be, and arising out of or in connection with the
acceptance or administration of this trust or in any other capacity hereunder,
including the costs and expenses of defending themselves against any claim
(whether asserted by the Company, any holder or any other Person) of liability
in the premises. The obligations of the Company under this Section 8.06 to
compensate or indemnify the Trustee and to pay or reimburse the Trustee for
expenses, disbursements and advances shall be secured by a lien prior to that of
the Debentures upon all property and funds held or collected by the Trustee as
such, except funds held in trust for the benefit of the holders of particular
Debentures. The obligation of the Company under this Section shall survive the
satisfaction and discharge of this Indenture.

         When the Trustee and its agents and any authenticating agent incur
expenses or render services after an Event of Default specified in Section
7.01(d) or (e) with respect to the Company occurs, the expenses and the
compensation for the services are intended to constitute expenses of
administration under any bankruptcy, insolvency or similar laws.

         Section 8.07. OFFICERS' CERTIFICATE AS EVIDENCE. Except as otherwise
provided in Section 8.01, whenever in the administration of the provisions of
this Indenture the Trustee shall deem it necessary or desirable that a matter be
proved or established prior to taking or omitting any action hereunder, such
matter (unless other evidence in respect thereof be herein specifically
prescribed) may, in the absence of bad faith or willful misconduct on the part
of the Trustee, be deemed to be conclusively proved and established by an
Officers' Certificate delivered to the Trustee.

         Section 8.08. CONFLICTING INTERESTS OF TRUSTEE. If the Trustee has or
shall acquire a conflicting interest within the meaning of the Trust Indenture
Act, the Trustee shall either eliminate such interest or resign, to the extent
and in the manner provided by, and subject to the provisions of, the Trust
Indenture Act and this Indenture.

         Section 8.09. ELIGIBILITY OF TRUSTEE. There shall at all times be a
Trustee hereunder which shall be a Person that is eligible pursuant to the Trust
Indenture Act to act as such and has a combined capital and surplus of at least
$50,000,000 (or if such Person is a member of a bank holding company system, its
bank holding company shall have a combined capital and surplus of at least
$50,000,000). If such Person publishes reports of condition at least annually,
pursuant to law or to the requirements of any supervising or examining
authority, then for the purposes of this Section the combined capital and
surplus of such Person shall be deemed to be its combined capital and surplus as
set forth in its most recent report of condition so published. If at any time
the Trustee shall cease to be eligible in accordance with the provisions of this
Section 8.09, it shall


                                       50
<Page>

resign immediately in the manner and with the effect hereinafter specified in
this Article.

         Section 8.10.  RESIGNATION OR REMOVAL OF TRUSTEE.

         (a) The Trustee may at any time resign by giving written notice of such
resignation to the Company and to the holders of Debentures. Upon receiving such
notice of resignation, the Company shall promptly appoint a successor trustee by
written instrument, in duplicate, executed by order of the Board of Directors,
one copy of which instrument shall be delivered to the resigning Trustee and one
copy to the successor trustee. If no successor trustee shall have been so
appointed and have accepted appointment sixty (60) days after the mailing of
such notice of resignation to the Debentureholders, the resigning Trustee may,
upon ten (10) Business Days' notice to the Company and the Debentureholders,
appoint a successor identified in such notice or may petition, at the expense of
the Company, any court of competent jurisdiction for the appointment of a
successor trustee, or, if any Debentureholder who has been a bona fide holder of
a Debenture or Debentures for at least six (6) months may, subject to the
provisions of Section 7.09, on behalf of himself and all others similarly
situated, petition any such court for the appointment of a successor trustee.
Such court may thereupon, after such notice, if any, as it may deem proper and
prescribe, appoint a successor trustee.

         (b) In case at any time any of the following shall occur:

                  (i) the Trustee shall fail to comply with Section 8.08 after
         written request therefor by the Company or by any Debentureholder who
         has been a bona fide holder of a Debenture or Debentures for at least
         six (6) months; or

                  (ii) the Trustee shall cease to be eligible in accordance with
         the provisions of Section 8.09 and shall fail to resign after written
         request therefor by the Company or by any such Debentureholder; or

                  (iii) the Trustee shall become incapable of acting, or shall
         be adjudged a bankrupt or insolvent, or a receiver of the Trustee or of
         its property shall be appointed, or any public officer shall take
         charge or control of the Trustee or of its property or affairs for the
         purpose of rehabilitation, conservation or liquidation;

then, in any such case, the Company may remove the Trustee and appoint a
successor trustee by written instrument, in duplicate, executed by order of the
Board of Directors, one copy of which instrument shall be delivered to the
Trustee so removed and one copy to the successor trustee, or, subject to the
provisions of Section 7.09, any Debentureholder who has been a bona fide holder
of a Debenture or Debentures for at least six (6) months may, on behalf of
himself and all others similarly situated, petition any court of competent
jurisdiction for the


                                       51
<Page>

removal of the Trustee and the appointment of a successor trustee; PROVIDED that
if no successor Trustee shall have been appointed and have accepted appointment
sixty (60) days after either the Company or the Debentureholders has removed the
Trustee, or the Trustee resigns, the Trustee so removed may petition, at the
expense of the Company, any court of competent jurisdiction for an appointment
of a successor trustee. Such court may thereupon, after such notice, if any, as
it may deem proper and prescribe, remove the Trustee and appoint a successor
trustee.

         (c) The holders of a majority in aggregate principal amount of the
Debentures at the time outstanding may at any time remove the Trustee and
nominate a successor trustee which shall be deemed appointed as successor
trustee unless, within ten (10) days after notice to the Company of such
nomination, the Company objects thereto, in which case the Trustee so removed or
any Debentureholder, or if such Trustee so removed or any Debentureholder fails
to act, the Company, upon the terms and conditions and otherwise as in Section
8.10(a) provided, may petition any court of competent jurisdiction for an
appointment of a successor trustee.

         (d) Any resignation or removal of the Trustee and appointment of a
successor trustee pursuant to any of the provisions of this Section 8.10 shall
become effective upon acceptance of appointment by the successor trustee as
provided in Section 8.11.

         Section 8.11. ACCEPTANCE BY SUCCESSOR TRUSTEE. Any successor trustee
appointed as provided in Section 8.10 shall execute, acknowledge and deliver to
the Company and to its predecessor trustee an instrument accepting such
appointment hereunder, and thereupon the resignation or removal of the
predecessor trustee shall become effective and such successor trustee, without
any further act, deed or conveyance, shall become vested with all the rights,
powers, duties and obligations of its predecessor hereunder, with like effect as
if originally named as trustee herein; but, nevertheless, on the written request
of the Company or of the successor trustee, the trustee ceasing to act shall,
upon payment of any amount then due it pursuant to the provisions of Section
8.06, execute and deliver an instrument transferring to such successor trustee
all the rights and powers of the trustee so ceasing to act. Upon request of any
such successor trustee, the Company shall execute any and all instruments in
writing for more fully and certainly vesting in and confirming to such successor
trustee all such rights and powers. Any trustee ceasing to act shall,
nevertheless, retain a lien upon all property and funds held or collected by
such trustee as such, except for funds held in trust for the benefit of holders
of particular Debentures, to secure any amounts then due it pursuant to the
provisions of Section 8.06.

         No successor trustee shall accept appointment as provided in this
Section 8.11 unless, at the time of such acceptance, such successor trustee
shall be qualified under the provisions of Section 8.08 and be eligible under
the provisions of Section 8.09.

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<Page>

         Upon acceptance of appointment by a successor trustee as provided in
this Section 8.11, the Company (or the former trustee, at the written direction
of the Company) shall mail or cause to be mailed notice of the succession of
such trustee hereunder to the holders of Debentures at their addresses as they
shall appear on the Debenture register. If the Company fails to mail such notice
within ten (10) days after acceptance of appointment by the successor trustee,
the successor trustee shall cause such notice to be mailed at the expense of the
Company.

         Section 8.12. SUCCESSION BY MERGER. Any corporation into which the
Trustee may be merged or converted or with which it may be consolidated, or any
corporation resulting from any merger, conversion or consolidation to which the
Trustee shall be a party, or any corporation succeeding to all or substantially
all of the corporate trust business of the Trustee (including any trust created
by this Indenture), shall be the successor to the Trustee hereunder without the
execution or filing of any paper or any further act on the part of any of the
parties hereto, provided that in the case of any corporation succeeding to all
or substantially all of the corporate trust business of the Trustee, such
corporation shall be qualified under the provisions of Section 8.08 and eligible
under the provisions of Section 8.09.

         In case at the time such successor to the Trustee shall succeed to the
trusts created by this Indenture, any of the Debentures shall have been
authenticated but not delivered, any such successor to the Trustee may adopt the
certificate of authentication of any predecessor trustee or authenticating agent
appointed by such predecessor trustee, and deliver such Debentures so
authenticated; and in case at that time any of the Debentures shall not have
been authenticated, any successor to the Trustee or any authenticating agent
appointed by such successor trustee may authenticate such Debentures in the name
of the successor trustee; and in all such cases such certificates shall have the
full force that is provided in the Debentures or in this Indenture; PROVIDED
that the right to adopt the certificate of authentication of any predecessor
Trustee or authenticate Debentures in the name of any predecessor Trustee shall
apply only to its successor or successors by merger, conversion or
consolidation.

         Section 8.13. PREFERENTIAL COLLECTION OF CLAIMS. If and when the
Trustee shall be or become a creditor of the Company (or any other obligor upon
the Debentures), the Trustee shall be subject to the provisions of the Trust
Indenture Act regarding the collection of the claims against the Company (or any
such other obligor).



                                    ARTICLE 9
                              THE DEBENTUREHOLDERS

         Section 9.01. ACTION BY DEBENTUREHOLDERS. Whenever in this Indenture it
is provided that the holders of a specified percentage in aggregate principal
amount of the Debentures may take any action (including the making of any


                                       53
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demand or request, the giving of any notice, consent or waiver or the taking of
any other action), the fact that at the time of taking any such action, the
holders of such specified percentage have joined therein may be evidenced (a) by
any instrument or any number of instruments of similar tenor executed by
Debentureholders in person or by agent or proxy appointed in writing, or (b) by
the record of the holders of Debentures voting in favor thereof at any meeting
of Debentureholders duly called and held in accordance with the provisions of
Article 10, or (c) by a combination of such instrument or instruments and any
such record of such a meeting of Debentureholders. Whenever the Company or the
Trustee solicits the taking of any action by the holders of the Debentures, the
Company or the Trustee may fix in advance of such solicitation, a date as the
record date for determining holders entitled to take such action. The record
date shall be not more than fifteen (15) days prior to the date of commencement
of solicitation of such action.

         Section 9.02. PROOF OF EXECUTION BY DEBENTUREHOLDERS. Subject to the
provisions of Sections 8.01, 8.02 and 10.05, proof of the execution of any
instrument by a Debentureholder or its agent or proxy shall be sufficient if
made in accordance with such reasonable rules and regulations as may be
prescribed by the Trustee or in such manner as shall be satisfactory to the
Trustee. The holding of Debentures shall be proved by the registry of such
Debentures or by a certificate of the Debenture registrar.

         The record of any Debentureholders' meeting shall be proved in the
manner provided in Section 10.06.

         Section 9.03. WHO ARE DEEMED ABSOLUTE OWNERS. The Company, the Trustee,
any paying agent, any conversion agent and any Debenture registrar may deem the
Person in whose name such Debenture shall be registered upon the Debenture
register to be, and may treat it as, the absolute owner of such Debenture
(whether or not such Debenture shall be overdue and notwithstanding any notation
of ownership or other writing thereon made by any Person other than the Company
or any Debenture registrar) for the purpose of receiving payment of or on
account of the principal of, premium, if any, and interest on such Debenture,
for conversion of such Debenture and for all other purposes; and neither the
Company nor the Trustee nor any paying agent nor any conversion agent nor any
Debenture registrar shall be affected by any notice to the contrary. All such
payments so made to any holder for the time being, or upon his order, shall be
valid, and, to the extent of the sum or sums so paid, effectual to satisfy and
discharge the liability for monies payable upon any such Debenture.

         Section 9.04. COMPANY-OWNED DEBENTURES DISREGARDED. In determining
whether the holders of the requisite aggregate principal amount of Debentures
have concurred in any direction, consent, waiver or other action under this
Indenture, Debentures which are owned by the Company or any other obligor on the
Debentures or any Affiliate of the Company or any other obligor on the
Debentures shall be disregarded and deemed not to be outstanding for the purpose


                                       54
<Page>

of any such determination; PROVIDED that for the purposes of determining whether
the Trustee shall be protected in relying on any such direction, consent, waiver
or other action, only Debentures which a Responsible Officer knows are so owned
shall be so disregarded. Debentures so owned which have been pledged in good
faith may be regarded as outstanding for the purposes of this Section 9.04 if
the pledgee shall establish to the satisfaction of the Trustee the pledgee's
right to vote such Debentures and that the pledgee is not the Company, any other
obligor on the Debentures or any Affiliate of the Company or any such other
obligor. In the case of a dispute as to such right, any decision by the Trustee
taken upon the advice of counsel shall be full protection to the Trustee. Upon
request of the Trustee, the Company shall furnish to the Trustee promptly an
Officers' Certificate listing and identifying all Debentures, if any, known by
the Company to be owned or held by or for the account of any of the above
described Persons, and, subject to Section 8.01, the Trustee shall be entitled
to accept such Officers' Certificate as conclusive evidence of the facts therein
set forth and of the fact that all Debentures not listed therein are outstanding
for the purpose of any such determination.

         Section 9.05. REVOCATION OF CONSENTS, FUTURE HOLDERS BOUND. At any time
prior to (but not after) the evidencing to the Trustee, as provided in Section
9.01, of the taking of any action by the holders of the percentage in aggregate
principal amount of the Debentures specified in this Indenture in connection
with such action, any holder of a Debenture which is shown by the evidence to be
included in the Debentures the holders of which have consented to such action
may, by filing written notice with the Trustee at its Corporate Trust Office and
upon proof of holding as provided in Section 9.02, revoke such action so far as
concerns such Debenture. Except as aforesaid, any such action taken by the
holder of any Debenture shall be conclusive and binding upon such holder and
upon all future holders and owners of such Debenture and of any Debentures
issued in exchange or substitution therefor, irrespective of whether any
notation in regard thereto is made upon such Debenture or any Debenture issued
in exchange or substitution therefor.



                                   ARTICLE 10
                          MEETINGS OF DEBENTUREHOLDERS

         Section 10.01. PURPOSE OF MEETINGS. A meeting of Debentureholders may
be called at any time and from time to time pursuant to the provisions of this
Article 10 for any of the following purposes:

                  (1) to give any notice to the Company or to the Trustee or to
         give any directions to the Trustee permitted under this Indenture, or
         to consent to the waiving of any default or Event of Default hereunder
         and its consequences, or to take any other action authorized to be
         taken by Debentureholders pursuant to any of the provisions of Article
         7;


                                       55
<Page>

                  (2) to remove the Trustee and nominate a successor trustee
         pursuant to the provisions of Article 8;

                  (3) to consent to the execution of an indenture or indentures
         supplemental hereto pursuant to the provisions of Section 11.02; or

                  (4) to take any other action authorized to be taken by or on
         behalf of the holders of any specified aggregate principal amount of
         the Debentures under any other provision of this Indenture or under
         applicable law.

         Section 10.02. CALL OF MEETINGS BY TRUSTEE. The Trustee may at any time
call a meeting of Debentureholders to take any action specified in Section
10.01, to be held at such time and at such place as the Trustee shall determine.
Notice of every meeting of the Debentureholders, setting forth the time and the
place of such meeting and in general terms the action proposed to be taken at
such meeting and the establishment of any record date pursuant to Section 9.01,
shall be mailed to holders of Debentures at their addresses as they shall appear
on the Debenture register. Such notice shall also be mailed to the Company. Such
notices shall be mailed not less than twenty (20) nor more than ninety (90) days
prior to the date fixed for the meeting.

         Any meeting of Debentureholders shall be valid without notice if the
holders of all Debentures then outstanding are present in person or by proxy or
if notice is waived before or after the meeting by the holders of all Debentures
outstanding, and if the Company and the Trustee are either present by duly
authorized representatives or have, before or after the meeting, waived notice.

         Section 10.03. CALL OF MEETINGS BY COMPANY OR DEBENTUREHOLDERS. In case
at any time the Company, pursuant to a resolution of its Board of Directors, or
the holders of at least ten percent (10%) in aggregate principal amount of the
Debentures then outstanding, shall have requested the Trustee to call a meeting
of Debentureholders, by written request setting forth in reasonable detail the
action proposed to be taken at the meeting, and the Trustee shall not have
mailed the notice of such meeting within twenty (20) days after receipt of such
request, then the Company or such Debentureholders may determine the time and
the place for such meeting and may call such meeting to take any action
authorized in Section 10.01, by mailing notice thereof as provided in Section
10.02.

         Section 10.04. QUALIFICATIONS FOR VOTING. To be entitled to vote at any
meeting of Debentureholders a person shall (a) be a holder of one or more
Debentures on the record date pertaining to such meeting or (b) be a person
appointed by an instrument in writing as proxy by a holder of one or more
Debentures on the record date pertaining to such meeting. The only persons who
shall be entitled to be present or to speak at any meeting of Debentureholders
shall be the persons entitled to vote at such meeting and their counsel and any


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<Page>

representatives of the Trustee and its counsel and any representatives of the
Company and its counsel.

         Section 10.05. REGULATIONS. Notwithstanding any other provisions of
this Indenture, the Trustee may make such reasonable regulations as it may deem
advisable for any meeting of Debentureholders, in regard to proof of the holding
of Debentures and of the appointment of proxies, and in regard to the
appointment and duties of inspectors of votes, the submission and examination of
proxies, certificates and other evidence of the right to vote, and such other
matters concerning the conduct of the meeting as it shall think fit.

         The Trustee shall, by an instrument in writing, appoint a temporary
chairman of the meeting, unless the meeting shall have been called by the
Company or by Debentureholders as provided in Section 10.03, in which case the
Company or the Debentureholders calling the meeting, as the case may be, shall
in like manner appoint a temporary chairman. A permanent chairman and a
permanent secretary of the meeting shall be elected by vote of the holders of a
majority in principal amount of the Debentures represented at the meeting and
entitled to vote at the meeting.

         Subject to the provisions of Section 9.04, at any meeting each
Debentureholder or proxyholder shall be entitled to one vote for each $1,000
principal amount of Debentures held or represented by him; PROVIDED that no vote
shall be cast or counted at any meeting in respect of any Debenture challenged
as not outstanding and ruled by the chairman of the meeting to be not
outstanding. The chairman of the meeting shall have no right to vote other than
by virtue of Debentures held by him or instruments in writing as aforesaid duly
designating him as the proxy to vote on behalf of other Debentureholders. Any
meeting of Debentureholders duly called pursuant to the provisions of Section
10.02 or 10.03 may be adjourned from time to time by the holders of a majority
of the aggregate principal amount of Debentures represented at the meeting,
whether or not constituting a quorum, and the meeting may be held as so
adjourned without further notice.

         Section 10.06. VOTING. The vote upon any resolution submitted to any
meeting of Debentureholders shall be by written ballot on which shall be
subscribed the signatures of the holders of Debentures or of their
representatives by proxy and the outstanding principal amount of the Debentures
held or represented by them. The permanent chairman of the meeting shall appoint
two inspectors of votes who shall count all votes cast at the meeting for or
against any resolution and who shall make and file with the secretary of the
meeting their verified written reports in duplicate of all votes cast at the
meeting. A record in duplicate of the proceedings of each meeting of
Debentureholders shall be prepared by the secretary of the meeting and there
shall be attached to said record the original reports of the inspectors of votes
on any vote by ballot taken thereat and affidavits by one or more persons having
knowledge of the facts setting forth a copy of the notice of the meeting and
showing that said notice was mailed as


                                       57
<Page>

provided in Section 10.02. The record shall show the principal amount of the
Debentures voting in favor of or against any resolution. The record shall be
signed and verified by the affidavits of the permanent chairman and secretary of
the meeting and one of the duplicates shall be delivered to the Company and the
other to the Trustee to be preserved by the Trustee, the latter to have attached
thereto the ballots voted at the meeting.

         Any record so signed and verified shall be conclusive evidence of the
matters therein stated.

         Section 10.07. NO DELAY OF RIGHTS BY MEETING. Nothing contained in this
Article 10 shall be deemed or construed to authorize or permit, by reason of any
call of a meeting of Debentureholders or any rights expressly or impliedly
conferred hereunder to make such call, any hindrance or delay in the exercise of
any right or rights conferred upon or reserved to the Trustee or to the
Debentureholders under any of the provisions of this Indenture or of the
Debentures.



                                   ARTICLE 11
                             SUPPLEMENTAL INDENTURES

         Section 11.01. SUPPLEMENTAL INDENTURES WITHOUT CONSENT OF
DEBENTUREHOLDERS. The Company, when authorized by the resolutions of the Board
of Directors, and the Trustee may, from time to time, and at any time enter into
an indenture or indentures supplemental hereto for one or more of the following
purposes:

         (a) make provision with respect to the conversion rights of the holders
of Debentures pursuant to the requirements of Section 15.06 and the redemption
obligations of the Company pursuant to the requirements of Section 3.05(e);

         (b) to convey, transfer, assign, mortgage or pledge to the Trustee as
security for the Debentures, any property or assets;

         (c) to evidence the succession of another Person to the Company, or
successive successions, and the assumption by the successor Person of the
covenants, agreements and obligations of the Company pursuant to Article 12;

         (d) to add to the covenants of the Company such further covenants,
restrictions or conditions as the Board of Directors and the Trustee shall
consider to be for the benefit of the holders of Debentures, and to make the
occurrence, or the occurrence and continuance, of a default in any such
additional covenants, restrictions or conditions a default or an Event of
Default permitting the enforcement of all or any of the several remedies
provided in this Indenture as herein set forth; PROVIDED that in respect of any
such additional covenant, restriction or condition, such supplemental indenture
may provide for a particular


                                       58
<Page>

period of grace after default (which period may be shorter or longer than that
allowed in the case of other defaults) or may provide for an immediate
enforcement upon such default or may limit the remedies available to the Trustee
upon such default;

         (e) to provide for the issuance under this Indenture of Debentures in
coupon form (including Debentures registrable as to principal only) and to
provide for exchangeability of such Debentures with the Debentures issued
hereunder in fully registered form and to make all appropriate changes for such
purpose;

         (f) to cure any ambiguity or to correct or supplement any provision
contained herein or in any supplemental indenture that may be defective or
inconsistent with any other provision contained herein or in any supplemental
indenture, or to make such other provisions in regard to matters or questions
arising under this Indenture that shall not materially adversely affect the
interests of the holders of the Debentures;

         (g) to evidence and provide for the acceptance of appointment hereunder
by a successor Trustee with respect to the Debentures; or

         (h) to modify, eliminate or add to the provisions of this Indenture to
such extent as shall be necessary to effect the qualifications of this Indenture
under the Trust Indenture Act, or under any similar federal statute hereafter
enacted.

         Upon the written request of the Company, accompanied by a copy of the
resolutions of the Board of Directors certified by its Secretary or Assistant
Secretary authorizing the execution of any supplemental indenture, the Trustee
is hereby authorized to join with the Company in the execution of any such
supplemental indenture, to make any further appropriate agreements and
stipulations that may be therein contained and to accept the conveyance,
transfer and assignment of any property thereunder, but the Trustee shall not be
obligated to, but may in its discretion, enter into any supplemental indenture
that affects the Trustee's own rights, duties or immunities under this Indenture
or otherwise.

         Any supplemental indenture authorized by the provisions of this Section
11.01 may be executed by the Company and the Trustee without the consent of the
holders of any of the Debentures at the time outstanding, notwithstanding any of
the provisions of Section 11.02.

         Notwithstanding any other provision of the Indenture or the Debentures,
the Registration Rights Agreement and the obligation to pay Liquidated Damages
thereunder may be amended, modified or waived in accordance with the provisions
of the Registration Rights Agreement.


                                       59
<Page>

         Section 11.02. SUPPLEMENTAL INDENTURE WITH CONSENT OF DEBENTUREHOLDERS.
With the consent (evidenced as provided in Article 9) of the holders of at least
a majority in aggregate principal amount of the Debentures at the time
outstanding, the Company, when authorized by the resolutions of the Board of
Directors, and the Trustee may, from time to time and at any time, enter into an
indenture or indentures supplemental hereto for the purpose of adding any
provisions to or changing in any manner or eliminating any of the provisions of
this Indenture or any supplemental indenture or of modifying in any manner the
rights of the holders of the Debentures; PROVIDED that no such supplemental
indenture shall (i) extend the fixed maturity of any Debenture, or reduce the
rate or extend the time of payment of interest thereon, or reduce the principal
amount thereof or premium, if any, thereon, or reduce any amount payable on
redemption or repurchase thereof, or impair the right of any Debentureholder to
institute suit for the payment thereof, or make the principal thereof or
interest or premium, if any, thereon payable in any coin or currency other than
that provided in the Debentures, or change the obligation of the Company to
redeem any Debenture on a redemption date in a manner adverse to the holders of
Debentures, or change the obligation of the Company to redeem any Debenture upon
the happening of a Fundamental Change in a manner adverse to the holders of
Debentures, or change the obligation of the Company to repurchase any Debenture
on a Repurchase Date in a manner adverse to the holders of Debentures, or impair
the right to convert the Debentures into Common Stock subject to the terms set
forth herein, including Section 15.06, in each case, without the consent of the
holder of each Debenture so affected, or modify any of the provisions of this
Section 11.02 or Section 7.07, except to increase any such percentage or to
provide that certain other provisions of this Indenture cannot be modified or
waived without the consent of the holder of each Debenture so affected, or
change any obligation of the Company to maintain an office or agency in the
places and for the purposes set forth in Section 5.01, or reduce the quorum or
voting requirements set forth in Article 10 or (ii) reduce the aforesaid
percentage of Debentures, the holders of which are required to consent to any
such supplemental indenture, without the consent of the holders of all
Debentures then outstanding.

         Upon the written request of the Company, accompanied by a copy of the
resolutions of the Board of Directors certified by its Secretary or Assistant
Secretary authorizing the execution of any such supplemental indenture, and upon
the filing with the Trustee of evidence of the consent of Debentureholders as
aforesaid, the Trustee shall join with the Company in the execution of such
supplemental indenture unless such supplemental indenture affects the Trustee's
own rights, duties or immunities under this Indenture or otherwise, in which
case the Trustee may in its discretion, but shall not be obligated to, enter
into such supplemental indenture.

         It shall not be necessary for the consent of the Debentureholders under
this Section 11.02 to approve the particular form of any proposed supplemental


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<Page>

indenture, but it shall be sufficient if such consent shall approve the
substance thereof.

         Section 11.03. EFFECT OF SUPPLEMENTAL INDENTURE. Any supplemental
indenture executed pursuant to the provisions of this Article 11 shall comply
with the Trust Indenture Act, as then in effect, provided that this Section
11.03 shall not require such supplemental indenture or the Trustee to be
qualified under the Trust Indenture Act prior to the time such qualification is
in fact required under the terms of the Trust Indenture Act or the Indenture has
been qualified under the Trust Indenture Act, nor shall it constitute any
admission or acknowledgment by any party to such supplemental indenture that any
such qualification is required prior to the time such qualification is in fact
required under the terms of the Trust Indenture Act or the Indenture has been
qualified under the Trust Indenture Act. Upon the execution of any supplemental
indenture pursuant to the provisions of this Article 11, this Indenture shall be
and be deemed to be modified and amended in accordance therewith and the
respective rights, limitation of rights, obligations, duties and immunities
under this Indenture of the Trustee, the Company and the holders of Debentures
shall thereafter be determined, exercised and enforced hereunder, subject in all
respects to such modifications and amendments and all the terms and conditions
of any such supplemental indenture shall be and be deemed to be part of the
terms and conditions of this Indenture for any and all purposes.

         Section 11.04. NOTATION ON DEBENTURES. Debentures authenticated and
delivered after the execution of any supplemental indenture pursuant to the
provisions of this Article 11 may bear a notation in form approved by the
Trustee as to any matter provided for in such supplemental indenture. If the
Company or the Trustee shall so determine, new Debentures so modified as to
conform, in the opinion of the Trustee and the Board of Directors, to any
modification of this Indenture contained in any such supplemental indenture may,
at the Company's expense, be prepared and executed by the Company, authenticated
by the Trustee (or an authenticating agent duly appointed by the Trustee
pursuant to Section 16.10) and delivered in exchange for the Debentures then
outstanding, upon surrender of such Debentures then outstanding.

         Section 11.05. EVIDENCE OF COMPLIANCE OF SUPPLEMENTAL INDENTURE TO BE
FURNISHED TO TRUSTEE. Prior to entering into any supplemental indenture, the
Trustee shall be provided with an Officers' Certificate and an Opinion of
Counsel as conclusive evidence that any supplemental indenture executed pursuant
hereto complies with the requirements of this Article 11.



                                   ARTICLE 12
                CONSOLIDATION, MERGER, SALE, CONVEYANCE AND LEASE

         Section 12.01. COMPANY MAY CONSOLIDATE ON CERTAIN TERMS. Subject to the
provisions of Section 12.02, the Company shall not consolidate or merge with


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or into any other Person or Persons (whether or not affiliated with the
Company), nor shall the Company or its successor or successors be a party or
parties to successive consolidations or mergers, nor shall the Company sell,
convey, transfer or lease the property and assets of the Company substantially
as an entirety, to any other Person (whether or not affiliated with the
Company), unless: (i) the Company is the surviving Person, or the resulting,
surviving or transferee Person is a corporation organized and existing under the
laws of the United States of America, any state thereof or the District of
Columbia; (ii) upon any such consolidation, merger, sale, conveyance, transfer
or lease, the due and punctual payment of the principal of and premium, if any,
and interest on all of the Debentures, according to their tenor and the due and
punctual performance and observance of all of the covenants and conditions of
this Indenture to be performed by the Company, shall be expressly assumed, by
supplemental indenture satisfactory in form to the Trustee, executed and
delivered to the Trustee by the Person (if other than the Company) formed by
such consolidation, or into which the Company shall have been merged, or by the
Person that shall have acquired or leased such property, and such supplemental
indenture shall provide for the applicable conversion rights set forth in
Section 15.06; and (iii) immediately after giving effect to the transaction
described above, no Event of Default, and no event which, after notice or lapse
of time or both, would become an Event of Default, shall have happened and be
continuing.

         Section 12.02. SUCCESSOR TO BE SUBSTITUTED. In case of any such
consolidation, merger, sale, conveyance, transfer or lease and upon the
assumption by the successor Person, by supplemental indenture, executed and
delivered to the Trustee and satisfactory in form to the Trustee, of the due and
punctual payment of the principal of and premium, if any, and interest on all of
the Debentures and the due and punctual performance of all of the covenants and
conditions of this Indenture to be performed by the Company, such successor
Person shall succeed to and be substituted for the Company, with the same effect
as if it had been named herein as the party of this first part. Such successor
Person thereupon may cause to be signed, and may issue either in its own name or
in the name of Aon Corporation any or all of the Debentures, issuable hereunder
that theretofore shall not have been signed by the Company and delivered to the
Trustee; and, upon the order of such successor Person instead of the Company and
subject to all the terms, conditions and limitations in this Indenture
prescribed, the Trustee shall authenticate and shall deliver, or cause to be
authenticated and delivered, any Debentures that previously shall have been
signed and delivered by the officers of the Company to the Trustee for
authentication, and any Debentures that such successor Person thereafter shall
cause to be signed and delivered to the Trustee for that purpose. All the
Debentures so issued shall in all respects have the same legal rank and benefit
under this Indenture as the Debentures theretofore or thereafter issued in
accordance with the terms of this Indenture as though all of such Debentures had
been issued at the date of the execution hereof. In the event of any such
consolidation, merger, sale, conveyance, transfer or lease, the Person named as
the "COMPANY" in the first paragraph of this Indenture or any successor


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that shall thereafter have become such in the manner prescribed in this Article
12 may be dissolved, wound up and liquidated at any time thereafter and such
Person shall be released from its liabilities as obligor and maker of the
Debentures and from its obligations under this Indenture.

         In case of any such consolidation, merger, sale, conveyance, transfer
or lease, such changes in phraseology and form (but not in substance) may be
made in the Debentures thereafter to be issued as may be appropriate.

         Section 12.03. OPINION OF COUNSEL TO BE GIVEN TRUSTEE. The Trustee
shall receive an Officers' Certificate and an Opinion of Counsel as conclusive
evidence that any such consolidation, merger, sale, conveyance, transfer or
lease and any such assumption complies with the provisions of this Article 12.



                                   ARTICLE 13
                     SATISFACTION AND DISCHARGE OF INDENTURE

         Section 13.01. DISCHARGE OF INDENTURE. When (a) the Company shall
deliver to the Trustee for cancellation all Debentures theretofore authenticated
(other than any Debentures that have been destroyed, lost or stolen and in lieu
of or in substitution for which other Debentures shall have been authenticated
and delivered) and not theretofore canceled, or (b) all the Debentures not
theretofore canceled or delivered to the Trustee for cancellation shall have
become due and payable, or are by their terms to become due and payable within
one year or are to be called for redemption within one year under arrangements
satisfactory to the Trustee for the giving of notice of redemption, and the
Company shall deposit with the Trustee, in trust, funds sufficient to pay at
maturity or upon redemption of all of the Debentures (other than any Debentures
that shall have been mutilated, destroyed, lost or stolen and in lieu of or in
substitution for which other Debentures shall have been authenticated and
delivered) not theretofore canceled or delivered to the Trustee for
cancellation, including principal and premium, if any, and interest due or to
become due to such date of maturity or redemption date, as the case may be,
accompanied by a verification report, as to the sufficiency of the deposited
amount, from an independent certified accountant or other financial professional
satisfactory to the Trustee, and if the Company shall also pay or cause to be
paid all other sums payable hereunder by the Company, then this Indenture shall
cease to be of further effect (except as to (i) remaining rights of registration
of transfer, substitution and exchange and conversion of Debentures, (ii) rights
hereunder of Debentureholders to receive payments of principal of and premium,
if any, and interest on, the Debentures and the other rights, duties and
obligations of Debentureholders, as beneficiaries hereof with respect to the
amounts, if any, so deposited with the Trustee and (iii) the rights, obligations
and immunities of the Trustee hereunder), and the Trustee, on written demand of
the Company accompanied by an Officers' Certificate and an Opinion of Counsel as
required by Section 16.04 and at the cost and expense of the


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Company, shall execute proper instruments acknowledging satisfaction of and
discharging this Indenture; the Company, however, hereby agrees to reimburse the
Trustee for any costs or expenses thereafter reasonably and properly incurred by
the Trustee and to compensate the Trustee for any services thereafter reasonably
and properly rendered by the Trustee in connection with this Indenture or the
Debentures.

         Section 13.02. DEPOSITED MONIES TO BE HELD IN TRUST BY TRUSTEE. Subject
to Section 13.04, all monies deposited with the Trustee pursuant to Section
13.01, shall be held in trust for the sole benefit of the Debentureholders, and
such monies shall be applied by the Trustee to the payment, either directly or
through any paying agent (including the Company if acting as its own paying
agent), to the holders of the particular Debentures for the payment or
redemption of which such monies have been deposited with the Trustee, of all
sums due and to become due thereon for principal and interest and premium, if
any.

         Section 13.03. PAYING AGENT TO REPAY MONIES HELD. Upon the satisfaction
and discharge of this Indenture, all monies then held by any paying agent of the
Debentures (other than the Trustee) shall, upon written request of the Company,
be repaid to it or paid to the Trustee, and thereupon such paying agent shall be
released from all further liability with respect to such monies.

         Section 13.04. RETURN OF UNCLAIMED MONIES. Subject to the requirements
of applicable law, any monies deposited with or paid to the Trustee for payment
of the principal of, premium, if any, or interest on Debentures and not applied
but remaining unclaimed by the holders of Debentures for two years after the
date upon which the principal of, premium, if any, or interest on such
Debentures, as the case may be, shall have become due and payable, shall be
repaid to the Company by the Trustee on demand and all liability of the Trustee
shall thereupon cease with respect to such monies; and the holder of any of the
Debentures shall thereafter look only to the Company for any payment that such
holder may be entitled to collect unless an applicable abandoned property law
designates another Person.

         Section 13.05. REINSTATEMENT. If the Trustee or the paying agent is
unable to apply any money in accordance with Section 13.02 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 Debentures shall be revived and reinstated as though no
deposit had occurred pursuant to Section 13.01 until such time as the Trustee or
the paying agent is permitted to apply all such money in accordance with Section
13.02; PROVIDED that if the Company makes any payment of interest on or
principal of any Debenture following the reinstatement of its obligations, the
Company shall be subrogated to the rights of the holders of such Debentures to
receive such payment from the money held by the Trustee or paying agent.


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                                   ARTICLE 14
         IMMUNITY OF INCORPORATORS, STOCKHOLDERS, OFFICERS AND DIRECTORS

         Section 14.01. INDENTURE AND DEBENTURES SOLELY CORPORATE OBLIGATIONS.
No recourse for the payment of the principal of or premium, if any, or interest
on any Debenture, or for any claim based thereon or otherwise in respect
thereof, and no recourse under or upon any obligation, covenant or agreement of
the Company in this Indenture or in any supplemental indenture or in any
Debenture, or because of the creation of any indebtedness represented thereby,
shall be had against any incorporator, stockholder, employee, agent, officer,
director or subsidiary, as such, past, present or future, of the Company or of
any successor corporation, either directly or through the Company or any
successor corporation, whether by virtue of any constitution, statute or rule of
law, or by the enforcement of any assessment or penalty or otherwise; it being
expressly understood that all such liability is hereby expressly waived and
released as a condition of, and as a consideration for, the execution of this
Indenture and the issue of the Debentures.



                                   ARTICLE 15
                            CONVERSION OF DEBENTURES

         Section 15.01. RIGHT TO CONVERT. (a) Subject to and upon compliance
with the provisions of this Indenture, prior to November 15, 2009, the holder of
any Debenture shall have the right, at such holder's option, to convert the
principal amount of the Debenture, or any portion of such principal amount which
is a multiple of $1,000, into fully paid and non-assessable shares of Common
Stock (as such shares shall then be constituted) at the Conversion Rate in
effect at such time, by surrender of the Debenture so to be converted in whole
or in part, together with any required funds, under the circumstances described
in this Section 15.01 and in the manner provided in Section 15.02. The
Debentures shall be convertible only upon the occurrence of one of the following
events:

                      (i) during any fiscal quarter commencing after December
         31, 2002, if the Closing Sale Price exceeds 120% of the Conversion
         Price in effect for at least 20 Trading Days in the 30 consecutive
         Trading Day period ending on the last Trading Day of the immediately
         preceding fiscal quarter (it being understood for purposes of this
         Section 15.01(a)(i) that the Conversion Price in effect at the close of
         business on each of the 30 consecutive Trading Days should be used);

                      (ii) during the five Business Day period after any ten
         consecutive Trading Day period in which the Trading Price per $1,000
         principal amount of the Debentures for each day of such ten day period
         was less than 95% of the product of the Closing Sale Price and the
         number of shares of Common Stock issuable upon conversion of $1,000
         principal amount of the Debentures; PROVIDED that if on the date of any
         conversion pursuant to this clause (ii) the Closing Sale Price of the
         Common Stock is


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<Page>

         greater than the Conversion Price, a holder shall receive, in lieu of
         Common Stock based on the Conversion Price, cash or Common Stock or a
         combination of cash and Common Stock, at the Company's option, with a
         value equal to the principal amount of the holder's Debentures plus
         accrued interest as of the conversion date (a "PRINCIPAL VALUE
         CONVERSION");

                      (iii) if such Debenture has been called for redemption, at
         any time on or after the date the notice of redemption has been given
         until the close of business on the Business Day immediately preceding
         the redemption date; or

                      (iv) as provided in Section (b) of this Section 15.01.

         The Trustee (or other conversion agent appointed by the Company) shall,
on behalf of the Company, determine on a daily basis whether the Debentures
shall be convertible as a result of the occurrence of an event specified in
clause (i) above and, if the Debentures shall be so convertible, the Trustee (or
other conversion agent appointed by the Company) shall promptly deliver to the
Company and the Trustee (if the Trustee is not the conversion agent) written
notice thereof. Whenever the Debentures shall become convertible pursuant to
this Section 15.01, the Company or, at the Company's request, the Trustee in the
name and at the expense of the Company, shall notify the holders of the event
triggering such convertibility in the manner provided in Section 16.03, and the
Company shall also publicly announce such information and publish it on the
Company's web site. Any notice so given shall be conclusively presumed to have
been duly given, whether or not the holder receives such notice.

         The Trustee (or other conversion agent appointed by the Company) shall
have no obligation to determine the Trading Price under this Section 15.01
unless the Company has requested such a determination; and the Company shall
have no obligation to make such request unless a holder provides it with
reasonable evidence that the Trading Price per $1,000 principal amount of
Debentures would be less than 95% of the product of the Closing Sale Price and
the number of shares of Common Stock issuable upon conversion of $1,000
principal amount of Debentures. If such evidence is provided, the Company shall
instruct the Trustee (or other conversion agent) to determine the Trading Price
of the Debentures beginning on the next Trading Day and on each successive
Trading Day until the Trading Price per $1,000 principal amount of Debentures is
greater than or equal to 95% of the product of the Closing Sale Price and the
number of shares issuable upon conversion of $1,000 principal amount of the
Debentures.

         (b) In addition, if:

                      (i) (A) the Company distributes to all holders of its
         Common Stock rights or warrants entitling them (for a period expiring
         within 45 days of the record date for the determination of the
         stockholders entitled to


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         receive such distribution) to subscribe for or purchase shares of
         Common Stock, at a price per share less than the average of the Closing
         Sale Price for the ten Trading Days immediately preceding, but not
         including, the date such distribution is first publicly announced by
         the Company, or (B) the Company distributes to all holders of its
         Common Stock, cash or other assets, debt securities or rights to
         purchase its securities, where the Fair Market Value of such
         distribution per share of Common Stock exceeds 10% of the Closing Sale
         Price on the Trading Day immediately preceding the date such
         distribution is first publicly announced by the Company, then, in
         either case, the Debentures may be surrendered for conversion at any
         time on and after the date that the Company gives notice to the holders
         of such distribution, which shall be not less than 20 days prior to the
         Ex-Dividend Time for such distribution, until the earlier of the close
         of business on the Business Day immediately preceding, but not
         including, the Ex-Dividend Time or the date the Company publicly
         announces that such distribution will not take place; PROVIDED that no
         adjustment to the Conversion Price or the ability of a holder of a
         Debenture to convert will be made if the holder will otherwise
         participate in such distribution without conversion; or

                      (ii) the Company consolidates with or merges with or into
         another Person or is a party to a binding share exchange or conveys,
         transfers, sells, leases or otherwise disposes of all or substantially
         all of its properties and assets, then the Debentures may be
         surrendered for conversion at any time from and after the date fifteen
         (15) days prior to the anticipated effective date of the transaction
         and ending on and including the date fifteen (15) days after the
         consummation of the transaction. The Board of Directors shall determine
         the anticipated effective date of the transaction, and such
         determination shall be conclusive and binding on the holders and shall
         be publicly announced by the Company and posted on its web site not
         later than two Business Day prior to such 15th day.

         "EX-DIVIDEND TIME" means, with respect to any distribution on shares of
Common Stock, the first date on which the shares of Common Stock trade regular
way on the principal securities market on which the shares of Common Stock are
then traded without the right to receive such distribution.

         (c) A Debenture in respect of which a holder is electing to exercise
its option to require redemption upon a Fundamental Change pursuant to Section
3.05 or repurchase pursuant to Section 3.06 may be converted only if such holder
withdraws its election in accordance with Section 3.05(b) or Section 3.08,
respectively. A holder of Debentures is not entitled to any rights of a holder
of Common Stock until such holder has converted his Debentures to Common Stock,
and only to the extent such Debentures are deemed to have been converted to
Common Stock under this Article 15.


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         Section 15.02. EXERCISE OF CONVERSION PRIVILEGE; ISSUANCE OF COMMON
STOCK ON CONVERSION; NO ADJUSTMENT FOR INTEREST OR DIVIDENDS. In order to
exercise the conversion privilege with respect to any Debenture in certificated
form, the Company must receive at the office or agency of the Company maintained
for that purpose or, at the option of such holder, the Corporate Trust Office,
such Debenture with the original or facsimile of the form entitled "CONVERSION
NOTICE" on the reverse thereof, duly completed and manually signed, together
with such Debentures duly endorsed for transfer, accompanied by the funds, if
any, required by the penultimate paragraph of this Section 15.02. Such notice
shall also state the name or names (with address or addresses) in which the
certificate or certificates for shares of Common Stock which shall be issuable
on such conversion shall be issued, and shall be accompanied by transfer or
similar taxes, if required pursuant to Section 15.07.

         In order to exercise the conversion privilege with respect to any
interest in a Global Debenture, the beneficial holder must complete, or cause to
be completed, the appropriate instruction form for conversion pursuant to the
Depositary's book-entry conversion program, deliver, or cause to be delivered,
by book-entry delivery an interest in such Global Debenture, furnish appropriate
endorsements and transfer documents if required by the Company or the Trustee or
conversion agent, and pay the funds, if any, required by this Section 15.02 and
any transfer taxes if required pursuant to Section 15.07.

         In the case of a Principal Value Conversion, a holder will receive
either cash, Common Stock or a combination of cash and Common Stock, at the
Company's option, with a value equal to the principal amount of the Debenture
converted plus accrued interest, as of the conversion date. If a holder
surrenders its Debentures for conversion and it is a Principal Value Conversion,
the Company will notify the holder by the second Trading Day following the
conversion date whether it will pay all or a portion of the principal amount
plus accrued and unpaid interest in cash, Common Stock or a combination of cash
and Common Stock, and in what percentage. Any Common Stock delivered upon a
Principal Value Conversion will be valued at the greater of (x) the Conversion
Price on the conversion date and (y) the Closing Sale Price on the third Trading
Day after the conversion date. The Company will pay any portion of the principal
amount plus accrued and unpaid interest to be paid in cash on the third Trading
Day after the conversion date. If the Company elects to deliver Common Stock to
pay any portion of such principal amount plus accrued and unpaid interest, it
will deliver Common Stock on the fourth Trading Day following the conversion
date.

         As promptly as practicable after satisfaction of the requirements for
conversion set forth above, subject to compliance with any restrictions on
transfer if shares issuable on conversion are to be issued in a name other than
that of the Debentureholder (as if such transfer were a transfer of the
Debenture or Debentures (or portion thereof) so converted), the Company shall
issue and shall deliver to such Debentureholder at the office or agency
maintained by the Company for such purpose pursuant to Section 5.02, a
certificate or certificates


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<Page>

for the number of full shares of Common Stock issuable upon the conversion of
such Debenture or portion thereof as determined by the Company in accordance
with the provisions of this Article 15 and a check or cash in respect of any
fractional interest in respect of a share of Common Stock arising upon such
conversion, calculated by the Company as provided in Section 15.03. In case any
Debenture of a denomination greater than $1,000 shall be surrendered for partial
conversion, and subject to Section 2.03, the Company shall execute and the
Trustee shall authenticate and deliver to the holder of the Debenture so
surrendered, without charge to him, a new Debenture or Debentures in authorized
denominations in an aggregate principal amount equal to the unconverted portion
of the surrendered Debenture.

         Each conversion shall be deemed to have been effected as to any such
Debenture (or portion thereof) on the date on which the requirements set forth
above in this Section 15.02 have been satisfied as to such Debenture (or portion
thereof), and the Person in whose name any certificate or certificates for
shares of Common Stock shall be issuable upon such conversion shall be deemed to
have become on said date the holder of record of the shares represented thereby;
PROVIDED that any such surrender on any date when the stock transfer books of
the Company shall be closed shall constitute the Person in whose name the
certificates are to be issued as the record holder thereof for all purposes on
the next succeeding day on which such stock transfer books are open, but such
conversion shall be at the Conversion Rate in effect on the date upon which such
Debenture shall be surrendered.

         Any Debenture or portion thereof surrendered for conversion during the
period from the close of business on the record date for any interest payment
date to the close of business on the Business Day preceding the following
interest payment date that has not been called for redemption during such period
shall be accompanied by payment, in immediately available funds or other funds
acceptable to the Company, of an amount equal to the interest otherwise payable
on such interest payment date on the principal amount being converted; PROVIDED
that no such payment need be made to the extent that there shall exist at the
time of conversion a default in the payment of interest on the Debentures.
Except as provided above in this Section 15.02, no payment or other adjustment
shall be made for interest accrued on any Debenture converted or for dividends
on any shares issued upon the conversion of such Debenture as provided in this
Article 15.

         Upon the conversion of an interest in a Global Debenture, the Trustee
(or other conversion agent appointed by the Company), or the Custodian at the
direction of the Trustee (or other conversion agent appointed by the Company),
shall make a notation on such Global Debenture as to the reduction in the
principal amount represented thereby. The Company shall notify the Trustee in
writing of any conversions of Debentures effected through any conversion agent
other than the Trustee.


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         Upon the conversion of a Debenture, that portion of the accrued but
unpaid interest, including accrued contingent interest, if any, and accrued Tax
Original Issue Discount attributable to the period from the issue date of the
Debenture to the conversion date, with respect to the converted Debenture shall
not be cancelled, extinguished or forfeited, but rather shall be deemed to be
paid in full to the holder thereof through delivery of the Common Stock
(together with the cash payment, if any in lieu of fractional shares) in
exchange for the Debenture being converted pursuant to the provisions hereof;
and the fair market value of such shares of Common Stock (together with any such
cash payment in lieu of fractional shares) shall be treated as issued, to the
extent thereof, first in exchange for and in satisfaction of our obligation to
pay the principal amount of the converted Debenture, the accrued but unpaid
interest, including contingent interest, if any, and accrued Tax Original Issue
Discount through the conversion date from the issue date, and the balance, if
any, of such fair market value of such Common Stock (and any such cash payment)
shall be treated as issued in exchange for and in satisfaction of the right to
convert the Debenture being converted pursuant to the provisions hereof.

         Section 15.03. CASH PAYMENTS IN LIEU OF FRACTIONAL SHARES. No
fractional shares of Common Stock or scrip certificates representing fractional
shares shall be issued upon conversion of Debentures. If more than one Debenture
shall be surrendered for conversion at one time by the same holder, the number
of full shares that shall be issuable upon conversion shall be computed on the
basis of the aggregate principal amount of the Debentures (or specified portions
thereof to the extent permitted hereby) so surrendered. If any fractional share
of stock would be issuable upon the conversion of any Debenture or Debentures,
the Company shall make an adjustment and payment therefor in cash at the current
market price thereof to the holder of Debentures. The current market price of a
share of Common Stock shall be the Closing Sale Price on the last Trading Day
immediately preceding the day on which the Debentures (or specified portions
thereof) are deemed to have been converted.

         Section 15.04. CONVERSION RATE. Each $1,000 principal amount of the
Debentures shall be convertible into the number of shares of Common Stock
specified in the form of Debenture (herein called the "CONVERSION RATE")
attached as Exhibit A hereto, subject to adjustment as provided in this Article
15.

         Section 15.05. ADJUSTMENT OF CONVERSION RATE. The Conversion Rate 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 Rate shall be increased so that the same shall equal the
rate determined by multiplying the Conversion Rate in effect at the opening of
business on the date following the date fixed for the determination of
stockholders entitled to receive such dividend or other distribution by a
fraction,


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                      (i) the numerator of which shall be the sum of the number
         of shares of Common Stock outstanding at the close of business on the
         date fixed for the determination of stockholders entitled to receive
         such dividend or other distribution plus the total number of shares of
         Common Stock constituting such dividend or other distribution; and

                      (ii) the denominator of which shall be the number of
         shares of Common Stock outstanding at the close of business on the date
         fixed for such determination,

such increase to become effective immediately after the opening of business on
the day following the date fixed for such determination. For the purpose of this
paragraph (a), the number of shares of Common Stock at any time outstanding
shall not include shares held in the treasury of the Company. The Company will
not pay any dividend or make any distribution on shares of Common Stock held in
the treasury of the Company. If any dividend or distribution of the type
described in this Section 15.05(a) is declared but not so paid or made, the
Conversion Rate shall again be adjusted to the Conversion Rate that 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 (for a period
expiring within forty-five (45) days after the date fixed for determination of
stockholders entitled to receive such rights or warrants) to subscribe for or
purchase shares of Common Stock at a price per share less than the Current
Market Price on the date fixed for determination of stockholders entitled to
receive such rights or warrants, the Conversion Rate shall be increased so that
the same shall equal the rate determined by multiplying the Conversion Rate in
effect immediately prior to the date fixed for determination of stockholders
entitled to receive such rights or warrants by a fraction,

                      (i) the numerator of which shall be the number of shares
         of Common Stock outstanding on the date fixed for determination of
         stockholders entitled to receive such rights or warrants plus the total
         number of additional shares of Common Stock offered for subscription or
         purchase, and

                      (ii) the denominator of which shall be the sum of the
         number of shares of Common Stock outstanding at the close of business
         on the date fixed for determination of stockholders entitled to receive
         such rights or warrants plus the number of shares that the aggregate
         offering price of the total number of shares so offered would purchase
         at such Current Market Price.

         Such adjustment shall be successively made whenever any such rights or
warrants are issued, and shall become effective immediately after the opening of
business on the day following the date fixed for determination of stockholders


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entitled to receive such rights or warrants. To the extent that shares of Common
Stock are not delivered after the expiration of such rights or warrants, the
Conversion Rate shall be readjusted to the Conversion Rate that 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. If such rights or warrants are not so issued, the Conversion
Rate shall again be adjusted to be the Conversion Rate that 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 by the Company for such rights or
warrants and any amount payable on exercise or conversion thereof, the value of
such consideration, if other than cash, to be determined by the Board of
Directors.

            (c) In case outstanding shares of Common Stock shall be subdivided
into a greater number of shares of Common Stock, the Conversion Rate in effect
at the opening of business on the day following the day upon which such
subdivision becomes effective shall be proportionately increased, and
conversely, in case outstanding shares of Common Stock shall be combined into a
smaller number of shares of Common Stock, the Conversion Rate in effect at the
opening of business on the day following the day upon which such combination
becomes effective shall be proportionately reduced, such increase or reduction,
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 or evidences of its indebtedness or assets (including securities, but
excluding any rights or warrants referred to in Section 15.05(b), and excluding
any dividend or distribution (x) paid exclusively in cash or (y) referred to in
Section 15.05(a) (any of the foregoing hereinafter in this Section 15.05(d))
called the "SECURITIES")), then, in each such case (unless the Company elects to
reserve such Securities for distribution to the Debentureholders upon the
conversion of the Debentures so that any such holder converting Debentures 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 Securities which such
holder would have received if such holder had converted its Debentures into
Common Stock immediately prior to the Record Date, the Conversion Rate shall be
increased so that the same shall be equal to the rate determined by multiplying
the Conversion Rate in effect on the Record Date with respect to such
distribution by a fraction,

                  (i) the numerator of which shall be the Current Market Price
         on such Record Date; and


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                  (ii) the denominator of which shall be the Current Market
         Price on such Record Date less the fair market value (as determined by
         the Board of Directors, whose determination shall be conclusive, and
         described in a resolution of the Board of Directors) on the Record Date
         of the portion of the Securities so distributed applicable to one share
         of Common Stock,

such adjustment to become effective immediately prior to the opening of business
on the day following such Record Date; PROVIDED that if the then fair market
value (as so determined) of the portion of the Securities so distributed
applicable to one share of Common Stock is equal to or greater than the Current
Market Price on the Record Date, in lieu of the foregoing adjustment, adequate
provision shall be made so that each Debentureholder shall have the right to
receive upon conversion the amount of Securities such holder would have received
had such holder converted each Debenture on the Record Date. If such dividend or
distribution is not so paid or made, the Conversion Rate shall again be adjusted
to be the Conversion Rate that would then be in effect if such dividend or
distribution had not been declared. If the Board of Directors determines the
fair market value of any distribution for purposes of this Section 15.05(d) by
reference to the actual or when issued trading market for any securities, it
must in doing so consider the prices in such market over the same period used in
computing the Current Market Price on the applicable Record Date.

         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), which
rights or warrants, until the occurrence of a specified event or events
("TRIGGER EVENT"): (i) are deemed to be transferred with such shares of Common
Stock; (ii) are not exercisable; and (iii) are also issued in respect of future
issuances of Common Stock, shall be deemed not to have been distributed for
purposes of this Section 15.05 (and no adjustment to the Conversion Rate under
this Section 15.05 will be required) until the occurrence of the earliest
Trigger Event, whereupon such rights and warrants shall be deemed to have been
distributed and an appropriate adjustment (if any is required) to the Conversion
Rate shall be made under this Section 15.05(d). If any such right or warrant,
including any such existing rights or warrants distributed prior to the date of
this Indenture, are subject to events, upon the occurrence of which such rights
or warrants become exercisable to purchase different securities, evidences of
indebtedness or other assets, then the date of the occurrence of any and each
such event shall be deemed to be the date of distribution and record date with
respect to new rights or warrants with such rights (and a termination or
expiration of the existing rights or warrants without exercise by any of the
holders 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 was counted
for purposes of calculating a distribution amount for which an adjustment to the
Conversion Rate under this Section 15.05 was made,


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<Page>

(1) in the case of any such rights or warrants that shall all have been redeemed
or repurchased without exercise by any holders thereof, the Conversion Rate
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 or holders 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 that shall have expired or been terminated
without exercise by any holders thereof, the Conversion Rate shall be readjusted
as if such rights and warrants had not been issued.

         No adjustment of the Conversion Rate shall be made pursuant to this
Section 15.05(d) in respect of rights or warrants distributed or deemed
distributed on any Trigger Event to the extent that such rights or warrants are
actually distributed, or reserved by the Company for distribution to holders of
Debentures upon conversion by such holders of Debentures to Common Stock.

         For purposes of this Section 15.05(d) and Section 15.05(a) and (b), any
dividend or distribution to which this Section 15.05(d) is applicable that also
includes shares of Common Stock, or rights or warrants to subscribe for or
purchase shares of Common Stock (or both), shall be deemed instead to be (1) a
dividend or distribution of the evidences of indebtedness, assets or shares of
capital stock other than such shares of Common Stock or rights or warrants (and
any Conversion Rate adjustment required by this Section 15.05(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 Rate adjustment required by Sections
15.05(a) and 15.05(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", "the date fixed for the
determination of stockholders entitled to receive such rights or warrants" and
"the date fixed for such determination" within the meaning of Section 15.05(a)
and 15.05(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
date fixed for such determination" within the meaning of Section 15.05(a).

            (e) In case the Company shall, by dividend or otherwise, distribute
to all holders of its Common Stock cash (excluding (x) any quarterly cash
dividend on the Common Stock to the extent the aggregate cash dividend per share
of Common Stock in any fiscal quarter does not exceed the greater of (A) the
amount per share of Common Stock of the next preceding quarterly cash dividend
on the Common Stock to the extent that such preceding quarterly dividend did not
require any adjustment of the Conversion Rate pursuant to this Section 15.05(e)
(as adjusted to reflect subdivisions, or combinations of the Common Stock), and
(B) 2.5% of the arithmetic average of the Closing Sale Price during the ten


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Trading Days immediately prior to the date of declaration of such dividend, and
(y) any dividend or distribution in connection with the liquidation, dissolution
or winding up of the Company, whether voluntary or involuntary), then, in such
case, the Conversion Rate shall be increased so that the same shall equal the
rate determined by multiplying the Conversion Rate in effect immediately prior
to the close of business on such record date by a fraction,

                  (i) the numerator of which shall be the Current Market Price
         on such record date; and

                  (ii) the denominator of which shall be the Current Market
         Price on such record date less the amount of cash so distributed (and
         not excluded as provided above) applicable to one share of Common
         Stock,

such adjustment to be effective immediately prior to the opening of business on
the day following the record date; PROVIDED that if the portion of the cash so
distributed applicable to one share of Common Stock is equal to or greater than
the Current Market Price on the record date, in lieu of the foregoing
adjustment, adequate provision shall be made so that each Debentureholder shall
have the right to receive upon conversion the amount of cash such holder would
have received had such holder converted each Debenture on the record date. If
such dividend or distribution is not so paid or made, the Conversion Rate shall
again be adjusted to be the Conversion Rate that would then be in effect if such
dividend or distribution had not been declared. If any adjustment is required to
be made as set forth in this Section 15.05(e) as a result of a distribution that
is a quarterly dividend, such adjustment shall be based upon the amount by which
such distribution exceeds the amount of the quarterly cash dividend permitted to
be excluded pursuant hereto. If an adjustment is required to be made as set
forth in this Section 15.05(e) above as a result of a distribution that is not a
quarterly dividend, such adjustment shall be based upon the full amount of the
distribution.

            (f) In case a tender or exchange offer made by the Company or any
Subsidiary for all or any portion of the Common Stock shall expire and such
tender or exchange offer (as amended upon the expiration thereof) shall require
the payment to stockholders of consideration per share of Common Stock having a
Fair Market Value (as determined by the Board of Directors, whose determination
shall be conclusive and described in a resolution of the Board of Directors)
that as of the last time (the "EXPIRATION TIME") tenders or exchanges may be
made pursuant to such tender or exchange offer (as it may be amended) exceeds
the Closing Sale Price of a share of Common Stock on the Trading Day next
succeeding the Expiration Time, the Conversion Rate shall be increased so that
the same shall equal the rate determined by multiplying the Conversion Rate in
effect immediately prior to the Expiration Time by a fraction,

                      (i) the numerator of which shall be the sum of (x) the
         Fair Market Value (determined as aforesaid) of the aggregate
         consideration payable to stockholders based on the acceptance (up to
         any maximum


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<Page>

         specified in the terms of the tender or exchange offer) of all shares
         validly tendered or exchanged and not withdrawn as of the Expiration
         Time (the shares deemed so accepted up to any such maximum, being
         referred to as the "PURCHASED SHARES") and (y) the product of the
         number of shares of Common Stock outstanding (less any Purchased
         Shares) at the Expiration Time and the Closing Sale Price of a share of
         Common Stock on the Trading Day next succeeding the Expiration Time,
         and

                      (ii) the denominator of which shall be the number of
         shares of Common Stock outstanding (including any tendered or exchanged
         shares) at the Expiration Time multiplied by the Closing Sale Price of
         a share of Common Stock on the Trading Day next succeeding the
         Expiration Time

such adjustment to become effective immediately prior to the opening of business
on the day following the Expiration Time. If the Company is obligated to
purchase shares pursuant to any such tender or exchange offer, but the Company
is permanently prevented by applicable law from effecting any such purchases or
all such purchases are rescinded, the Conversion Rate shall again be adjusted to
be the Conversion Rate that would then be in effect if such tender or exchange
offer had not been made.

            (g) In case of a tender or exchange offer made by a Person other
than the Company or any Subsidiary for an amount that increases the offeror's
ownership of Common Stock to more than twenty-five percent (25%) of the Common
Stock outstanding and shall involve the payment by such Person of consideration
per share of Common Stock having a Fair Market Value (as determined by the Board
of Directors, whose determination shall be conclusive, and described in a
resolution of the Board of Directors) that as of the last time (the "OFFER
EXPIRATION TIME") tenders or exchanges may be made pursuant to such tender or
exchange offer (as it shall have been amended) exceeds the Closing Price of a
share of Common Stock on the Trading Day next succeeding the Offer Expiration
Time, and in which, as of the Offer Expiration Time the Board of Directors is
not recommending rejection of the offer, the Conversion Rate shall be increased
so that the same shall equal the rate determined by multiplying the Conversion
Rate in effect immediately prior to the Offer Expiration Time by a fraction

                      (i) the numerator of which shall be the sum of (x) the
         Fair Market Value (determined as aforesaid) of the aggregate
         consideration payable to stockholders based on the acceptance (up to
         any maximum specified in the terms of the tender or exchange offer) of
         all shares validly tendered or exchanged and not withdrawn as of the
         Offer Expiration Time (the shares deemed so accepted, up to any such
         maximum, being referred to as the "ACCEPTED PURCHASED SHARES") and (y)
         the product of the number of shares of Common Stock outstanding (less
         any Accepted Purchased Shares) at the Offer Expiration Time and the
         Closing Sale Price


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<Page>

         of a share of Common Stock on the Trading Day next succeeding the Offer
         Expiration Time, and

                      (ii) the denominator of which shall be the number of
         shares of Common Stock outstanding (including any tendered or exchanged
         shares) at the Offer Expiration Time multiplied by the Closing Sale
         Price of a share of Common Stock on the Trading Day next succeeding the
         Offer Expiration Time,

such adjustment to become effective immediately prior to the opening of business
on the day following the Offer Expiration Time. If such Person is obligated to
purchase shares pursuant to any such tender or exchange offer, but such Person
is permanently prevented by applicable law from effecting any such purchases or
all such purchases are rescinded, the Conversion Rate shall again be adjusted to
be the Conversion Rate that would then be in effect if such tender or exchange
offer had not been made. Notwithstanding the foregoing, the adjustment described
in this Section 15.05(g) shall not be made if, as of the Offer Expiration Time,
the offering documents with respect to such offer disclose a plan or intention
to cause the Company to engage in any transaction described in Article 12.

            (h) For purposes of this Section 15.05, the following terms shall
have the meaning indicated:

                      (i) "CURRENT MARKET PRICE" shall mean the average of the
         daily Closing Sale Prices per share of Common Stock for the ten
         consecutive Trading Days selected by the Company commencing no more
         than 30 Trading Days before and ending not later than the earlier of
         such date of determination and the day before the "EX" date with
         respect to the issuance, distribution, subdivision or combination
         requiring such computation immediately prior to the date in question.
         For purpose of this paragraph, 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 Sale Price was obtained
         without the right to receive such issuance or distribution, and (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.

         If another issuance, distribution, subdivision or combination to which
Section 15.05 applies occurs during the period applicable for calculating
"CURRENT MARKET PRICE" pursuant to the definition in the preceding paragraph,
"CURRENT MARKET PRICE" shall be calculated for such period in a manner
determined by the Board of Directors to reflect the impact of such issuance,
distribution, subdivision or combination on the Closing Sale Price of the Common
Stock during such period.


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                      (ii) "FAIR MARKET VALUE" shall mean the amount which a
         willing buyer would pay a willing seller in an arm's-length
         transaction.

                      (iii) "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).

                      (iv) "TRADING DAY" shall mean (x) if the applicable
         security is quoted on the Nasdaq National Market, a day on which trades
         may be made thereon or (y) if the applicable security is listed or
         admitted for trading on the New York Stock Exchange or another national
         securities exchange, a day on which the New York Stock Exchange or
         another national securities exchange is open for business 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 increases in the Conversion Rate, in
addition to those required by Section 15.05(a), (b), (c), (d), (e), (f) or (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 increase the Conversion Rate by any amount for any period of time if
the period is at least twenty (20) days, the increase is irrevocable during the
period and the Board of Directors shall have made a determination that such
increase would be in the best interests of the Company, which determination
shall be conclusive. Whenever the Conversion Rate is increased pursuant to the
preceding sentence, the Company shall mail to holders of record of the
Debentures a notice of the increase at least fifteen (15) days prior to the date
the increased Conversion Rate takes effect, and such notice shall state the
increased Conversion Rate and the period during which it will be in effect.

         (j) No adjustment in the Conversion Rate shall be required unless such
adjustment would require an increase or decrease of at least one percent (1%) in
such rate; PROVIDED that any adjustments that by reason of this Section 15.05(j)
are not required to be made shall be carried forward and taken into account in
any subsequent adjustment. All calculations under this Article 15 shall be made
by the Company and shall be made to the nearest cent or to the nearest one-ten
thousandth (1/10,000) of a share, as the case may be. No adjustment need be


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made for rights to purchase Common Stock pursuant to a Company plan for
reinvestment of dividends or interest or for any issuance of Common Stock or
convertible or exchangeable securities or rights to purchase Common Stock or
convertible or exchangeable securities. To the extent the Debentures become
convertible into cash, assets, property or securities (other than capital stock
of the Company), no adjustment need be made thereafter as to the cash, assets,
property or such securities. Interest will not accrue on any cash into which the
Debentures are convertible.

            (k) Whenever the Conversion Rate 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 Rate after
such adjustment and setting forth a brief statement of the facts requiring such
adjustment. Unless and until a Responsible 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 Rate and may assume that the last
Conversion Rate of which it has knowledge is still in effect. Promptly after
delivery of such certificate, the Company shall prepare a notice of such
adjustment of the Conversion Rate setting forth the adjusted Conversion Rate and
the date on which each adjustment becomes effective and shall mail such notice
of such adjustment of the Conversion Rate to the holder of each Debenture at his
last address appearing on the Debenture register provided for in Section 2.05 of
this Indenture, within twenty (20) days after execution thereof. Failure to
deliver such notice shall not affect the legality or validity of any such
adjustment.

            (l) In any case in which this Section 15.05 provides that an
adjustment shall become effective immediately after (1) a record date or Record
Date for an event, (2) the date fixed for the determination of stockholders
entitled to receive a dividend or distribution pursuant to Section 15.05(a), (3)
a date fixed for the determination of stockholders entitled to receive rights or
warrants pursuant to Section 15.05(b), (4) the Expiration Time for any tender or
exchange offer pursuant to Section 15.05(f), or (5) the Offer Expiration Time
for a tender or exchange offer pursuant to Section 15.05(g)(i) (each a
"DETERMINATION DATE"), the Company may elect to defer until the occurrence of
the applicable Adjustment Event (as hereinafter defined) (x) issuing to the
holder of any Debenture converted after such Determination Date and before the
occurrence of such Adjustment Event, the additional shares of Common Stock or
other securities issuable upon such conversion by reason of the adjustment
required by such Adjustment Event over and above the Common Stock issuable upon
such conversion before giving effect to such adjustment and (y) paying to such
holder any amount in cash in lieu of any fraction pursuant to Section 15.03. For
purposes of this Section 15.05(l), the term "ADJUSTMENT EVENT" shall mean:

                  (i) in any case referred to in clause (1) hereof, the
         occurrence of such event,


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                  (ii) in any case referred to in clause (2) hereof, the date
         any such dividend or distribution is paid or made,

                  (iii) in any case referred to in clause (3) hereof, the date
         of expiration of such rights or warrants, and

                  (iv) in any case referred to in clause (4) or clause (5)
         hereof, the date a sale or exchange of Common Stock pursuant to such
         tender or exchange offer is consummated and becomes irrevocable.

         (m) For purposes of this Section 15.05, 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 15.06. EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR
SALE. If any of the following events occur, namely (i) any reclassification or
change of the outstanding shares of Common Stock (other than a subdivision or
combination to which Section 15.05(c) applies), (ii) any consolidation, merger
or combination of the Company with another Person as a result of which holders
of Common Stock shall be entitled to receive stock, other 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 all or substantially all of the
properties and assets of the Company to any other Person as a result of which
holders of Common Stock shall be entitled to receive stock, other securities or
other property or assets (including cash) with respect to or in exchange for
such Common Stock, then the Company or the successor or purchasing Person, as
the case may be, shall execute with the Trustee a supplemental indenture (which
shall comply with the Trust Indenture Act as in force at the date of execution
of such supplemental indenture) providing that each Debenture shall be
convertible into the kind and amount of shares of stock, other securities or
other 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 Debentures
(assuming, for such purposes, a sufficient number of authorized shares of Common
Stock are available to convert all such Debentures) immediately prior to such
reclassification, change, consolidation, merger, combination, sale or conveyance
assuming such holder of Common Stock did not exercise his rights of election, if
any, as to the kind or amount of stock, other securities or other property or
assets (including cash) receivable upon such reclassification, change,
consolidation, merger, combination, sale or conveyance (provided that, if the
kind or amount of stock, other securities or other property or assets (including
cash) receivable upon such reclassification, change, consolidation, merger,
combination, sale or conveyance is not the same for each share of Common Stock
in respect of which such rights of election shall not have been exercised
("non-electing share"), then for the purposes of this Section 15.06


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<Page>

the kind and amount of stock, other securities or other property or assets
(including cash) receivable upon such reclassification, change, consolidation,
merger, combination, sale or conveyance for each non-electing share shall be
deemed to be the kind and amount so receivable per share by a plurality of the
non-electing shares). 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 15.

         The Company shall cause notice of the execution of such supplemental
indenture to be mailed to each holder of Debentures, at its address appearing on
the Debenture register provided for in Section 2.05 of this Indenture, within
twenty (20) days after execution thereof. Failure to deliver such notice shall
not affect the legality or validity of such supplemental indenture.

         The above provisions of this Section shall similarly apply to
successive reclassifications, changes, consolidations, mergers, combinations,
sales and conveyances.

         If this Section 15.06 applies to any event or occurrence, Section 15.05
shall not apply.

         Section 15.07. TAXES ON SHARES ISSUED. The issue of stock certificates
on conversions of Debentures shall be made without charge to the converting
Debentureholder for any documentary, stamp or similar issue or transfer tax in
respect of the issue thereof. The Company shall not, however, be required to pay
any such tax which may be payable in respect of any transfer involved in the
issue and delivery of stock in any name other than that of the holder of any
Debenture converted, and the Company shall not be required to issue or deliver
any such stock certificate unless and until the Person or Persons requesting the
issue thereof shall have paid to the Company the amount of such tax or shall
have established to the satisfaction of the Company that such tax has been paid.

         Section 15.08. RESERVATION OF SHARES, SHARES TO BE FULLY PAID;
COMPLIANCE WITH GOVERNMENTAL REQUIREMENTS; LISTING OF COMMON STOCK. The Company
shall provide, free from preemptive rights, out of its authorized but unissued
shares or shares held in treasury, sufficient shares of Common Stock to provide
for the conversion of the Debentures from time to time as such Debentures are
presented for conversion.

         Before taking any action which would cause an adjustment increasing the
Conversion Rate to an amount that would cause the Conversion Price to be reduced
below the then par value, if any, of the shares of Common Stock issuable upon
conversion of the Debentures, the Company will take all corporate action which
may, in the opinion of its counsel, be necessary in order that the Company may
validly and legally issue shares of such Common Stock at such adjusted
Conversion Rate.


                                       81
<Page>

         The Company covenants that all shares of Common Stock which may be
issued upon conversion of Debentures will upon issue be fully paid and
non-assessable by the Company and free from all taxes, liens and charges with
respect to the issue thereof.

         The Company covenants that, if any shares of Common Stock to be
provided for the purpose of conversion of Debentures hereunder require
registration with or approval of any governmental authority under any federal or
state law before such shares may be validly issued upon conversion, the Company
will in good faith and as expeditiously as possible, to the extent then
permitted by the rules and interpretations of the Commission (or any successor
thereto), endeavor to secure such registration or approval, as the case may be.

         The Company further covenants that, if at any time the Common Stock
shall be listed on the Nasdaq National Market or any other national securities
exchange or automated quotation system, the Company will, if permitted by the
rules of such exchange or automated quotation system, list and keep listed, so
long as the Common Stock shall be so listed on such exchange or automated
quotation system, all Common Stock issuable upon conversion of the Debenture;
PROVIDED that if the rules of such exchange or automated quotation system permit
the Company to defer the listing of such Common Stock until the first conversion
of the Debentures into Common Stock in accordance with the provisions of this
Indenture, the Company covenants to list such Common Stock issuable upon
conversion of the Debentures in accordance with the requirements of such
exchange or automated quotation system at such time.

         Section 15.09. RESPONSIBILITY OF TRUSTEE. The Trustee and any other
conversion agent shall not at any time be under any duty or responsibility to
any holder of Debentures to determine the Conversion Rate or whether any
facts exist which may require any adjustment of the Conversion Rate, or with
respect to the nature or extent or calculation of any such adjustment when
made, or with respect to the method employed, or herein or in any
supplemental indenture provided to be employed, in making the same. The
Trustee and any other conversion agent shall not be accountable with respect
to the validity or value (or the kind or amount) of any shares of Common
Stock, or of any securities or property, which may at any time be issued or
delivered upon the conversion of any Debenture; and the Trustee and any other
conversion agent make no representations with respect thereto. Neither the
Trustee nor any conversion agent shall be responsible for any failure of the
Company to issue, transfer or deliver any shares of Common Stock or stock
certificates or other securities or property or cash upon the surrender of
any Debenture for the purpose of conversion or to comply with any of the
duties, responsibilities or covenants of the Company contained in this
Article 15. Without limiting the generality of the foregoing, neither the
Trustee nor any conversion agent shall be under any responsibility to
determine the correctness of any provisions contained in any supplemental
indenture entered into pursuant to Section 15.06 relating either to the kind
or amount of shares of stock or securities or property (including cash)
receivable by Debentureholders upon the conversion

                                       82
<Page>

of their Debentures after any event referred to in such Section 15.06 or to
any adjustment to be made with respect thereto, but, subject to the
provisions of Section 8.01, may accept as conclusive evidence of the
correctness of any such provisions, and shall be protected in relying upon,
the Officers' Certificate (which the Company shall be obligated to file with
the Trustee prior to the execution of any such supplemental indenture) with
respect thereto.

         Section 15.10.  NOTICE TO HOLDERS PRIOR TO CERTAIN ACTIONS.  In case:

         (a) the Company shall declare a dividend (or any other distribution) on
its Common Stock that would require an adjustment in the Conversion Rate
pursuant to Section 15.05; or

         (b) the Company shall authorize the granting to the holders of all or
substantially all of its Common Stock of rights or warrants to subscribe for or
purchase any share of any class or any other rights or warrants; or

         (c) of any reclassification or reorganization of the Common Stock of
the Company (other than a subdivision or combination of its outstanding Common
Stock, or a change in par value, or from par value to no par value, or from no
par value to par value), or of any consolidation or merger to which the Company
is a party and for which approval of any stockholders of the Company is
required, or of the sale or transfer of all or substantially all of the assets
of the Company; or

         (d) of the voluntary or involuntary dissolution, liquidation or winding
up of the Company;

the Company shall cause to be filed with the Trustee and to be mailed to each
holder of Debentures at his address appearing on the Debenture register provided
for in Section 2.05 of this Indenture, as promptly as possible but in any event
at least ten (10) days prior to the applicable date hereinafter specified, a
notice stating (x) the date on which a record is to be taken for the purpose of
such dividend, distribution or rights or warrants, or, if a record is not to be
taken, the date as of which the holders of Common Stock of record to be entitled
to such dividend, distribution or rights are to be determined, or (y) the date
on which such reclassification, consolidation, merger, sale, transfer,
dissolution, liquidation or winding up is expected to become effective or occur,
and the date as of which it is expected that holders of Common Stock of record
shall be entitled to exchange their Common Stock for securities or other
property deliverable upon such reclassification, consolidation, merger, sale,
transfer, dissolution, liquidation or winding up. Failure to give such notice,
or any defect therein, shall not affect the legality or validity of such
dividend, distribution, reclassification, consolidation, merger, sale, transfer,
dissolution, liquidation or winding up.

         Section 15.11. FUTURE STOCKHOLDER RIGHTS PLANS. If the Company
hereafter adopts any stockholder rights plan, a Debentureholder shall be
entitled to receive upon conversion of their Debentures in addition to the
shares of

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Common Stock issuable upon conversion the related rights for the Common Stock
whether or not the rights under the future stockholder rights plan have
separated from the Common Stock at the time of conversion but otherwise subject
to the generally applicable terms of such plan and no additional adjustment to
the Conversion Rate shall be made.



                                   ARTICLE 16
                            MISCELLANEOUS PROVISIONS

         Section 16.01. PROVISIONS BINDING ON COMPANY'S SUCCESSORS. All the
covenants, stipulations, promises and agreements by the Company contained in
this Indenture shall bind its successors and assigns whether so expressed or
not.

         Section 16.02. OFFICIAL ACTS BY SUCCESSOR CORPORATION. Any act or
proceeding by any provision of this Indenture authorized or required to be done
or performed by any board, committee or officer of the Company shall and may be
done and performed with like force and effect by the like board, committee or
officer of any Person that shall at the time be the lawful sole successor of the
Company.

         Section 16.03. ADDRESSES FOR NOTICES, ETC. Any notice or demand which
by any provision of this Indenture is required or permitted to be given or
served by the Trustee or by the holders of Debentures on the Company shall be
deemed to have been sufficiently given or made, for all purposes, if given or
served by being deposited postage prepaid by registered or certified mail in a
post office letter box or sent by telecopier transmission addressed as follows:
to Aon Corporation, 200 East Randolph Street, Chicago, Illinois 60601,
Telecopier No.: (312) 381-6060 Attention: Treasurer. Any notice, direction,
request or demand hereunder to or upon the Trustee shall be deemed to have been
sufficiently given or made, for all purposes, if given or served by being
deposited, postage prepaid, by registered or certified mail in a post office
letter box or sent by telecopier transmission addressed as follows: The Bank of
New York, c/o BNY Midwest Trust Company, 2 North LaSalle Street, Suite 1020,
Chicago, Illinois 60602, Attention: Corporate Trust Department.

         The Trustee, by notice to the Company, may designate additional or
different addresses for subsequent notices or communications.

         Any notice or communication mailed to a Debentureholder shall be mailed
to him by first class mail, postage prepaid, at his address as it appears on the
Debenture register and shall be sufficiently given to him if so mailed within
the time prescribed.

         Failure to mail a notice or communication to a Debentureholder or any
defect in it shall not affect its sufficiency with respect to other
Debentureholders.


                                       84
<Page>

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

         Section 16.04. GOVERNING LAW. This Indenture and each Debenture shall
be deemed to be a contract made under the laws of the State of New York, and for
all purposes shall be construed in accordance with the laws of the State of New
York, without regard to conflicts of laws principles thereof.

         Section 16.05. EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT,
CERTIFICATES TO TRUSTEE. Upon any application or demand by the Company to the
Trustee to take any action under any of the provisions of this Indenture, the
Company shall furnish to the Trustee an Officers' Certificate stating that all
conditions precedent, if any, provided for in this Indenture relating to the
proposed action have been complied with, and an Opinion of Counsel stating that,
in the opinion of such counsel, all such conditions precedent have been complied
with.

         Each certificate or opinion provided for in this Indenture and
delivered to the Trustee 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 statement or opinion contained in such certificate or opinion is
based; (3) a statement that, in the opinion of such person, he has made such
examination or investigation as is necessary to enable him 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 16.06. LEGAL HOLIDAYS. In any case in which the date of
maturity of interest on or principal of the Debentures or the redemption date of
any Debenture will not be a Business Day, then payment of such interest on or
principal of the Debentures need not be made on such date, but may be made on
the next succeeding Business Day with the same force and effect as if made on
the date of maturity or the redemption date, and no interest shall accrue for
the period from and after such date.

         Section 16.07. TRUST INDENTURE ACT. This Indenture is hereby made
subject to, and shall be governed by, the provisions of the Trust Indenture Act
required to be part of and to govern indentures qualified under the Trust
Indenture Act; PROVIDED that unless otherwise required by law, notwithstanding
the foregoing, this Indenture and the Debentures issued hereunder shall not be
subject to the provisions of subsections (a)(1), (a)(2), and (a)(3) of Section
314 of the Trust Indenture Act as now in effect or as hereafter amended or
modified; PROVIDED further that this Section 16.07 shall not require this
Indenture or the Trustee to be qualified under the Trust Indenture Act prior to
the time such qualification is in fact required under the terms of the Trust
Indenture Act, nor


                                       85
<Page>

shall it constitute any admission or acknowledgment by any party to the
Indenture that any such qualification is required prior to the time such
qualification is in fact required under the terms of the Trust Indenture Act. If
any provision hereof limits, qualifies or conflicts with another provision
hereof which is required to be included in an indenture qualified under the
Trust Indenture Act, such required provision shall control.

         Section 16.08. NO SECURITY INTEREST CREATED. Nothing in this Indenture
or in the Debentures, expressed or implied, shall be construed to constitute a
security interest under the Uniform Commercial Code or similar legislation, as
now or hereafter enacted and in effect, in any jurisdiction in which property of
the Company or its subsidiaries is located.

         Section 16.09. BENEFITS OF INDENTURE. Nothing in this Indenture or in
the Debentures, express or implied, shall give to any Person, other than the
parties hereto, any paying agent, any authenticating agent, any Debenture
registrar and their successors hereunder and the holders of Debentures any
benefit or any legal or equitable right, remedy or claim under this Indenture.

         Section 16.10. TABLE OF CONTENTS, HEADINGS, ETC. The table of contents
and the titles 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.

         Section 16.11. AUTHENTICATING AGENT. The Trustee may appoint an
authenticating agent that shall be authorized to act on its behalf, and subject
to its direction, in the authentication and delivery of Debentures in connection
with the original issuance thereof and transfers and exchanges of Debentures
hereunder, including under Sections 2.04, 2.05, 2.06, 2.07, 3.03 and 3.05, as
fully to all intents and purposes as though the authenticating agent had been
expressly authorized by this Indenture and those Sections to authenticate and
deliver Debentures. For all purposes of this Indenture, the authentication and
delivery of Debentures by the authenticating agent shall be deemed to be
authentication and delivery of such Debentures "by the Trustee" and a
certificate of authentication executed on behalf of the Trustee by an
authenticating agent shall be deemed to satisfy any requirement hereunder or in
the Debentures for the Trustee's certificate of authentication. Such
authenticating agent shall at all times be a Person eligible to serve as trustee
hereunder pursuant to Section 8.09.

         Any corporation into which any authenticating agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, consolidation or conversion to which any authenticating agent
shall be a party, or any corporation succeeding to the corporate trust business
of any authenticating agent, shall be the successor of the authenticating agent
hereunder, if such successor corporation is otherwise eligible under this
Section 16.11,


                                       86
<Page>

without the execution or filing of any paper or any further act on the part of
the parties hereto or the authenticating agent or such successor corporation.

         Any authenticating agent may at any time resign by giving written
notice of resignation to the Trustee and to the Company. The Trustee may at any
time terminate the agency of any authenticating agent by giving written notice
of termination to such authenticating agent and to the Company. Upon receiving
such a notice of resignation or upon such a termination, or in case at any time
any authenticating agent shall cease to be eligible under this Section, the
Trustee shall either promptly appoint a successor authenticating agent or itself
assume the duties and obligations of the former authenticating agent under this
Indenture and, upon such appointment of a successor authenticating agent, if
made, shall give written notice of such appointment of a successor
authenticating agent to the Company and shall mail notice of such appointment of
a successor authenticating agent to all holders of Debentures as the names and
addresses of such holders appear on the Debenture register.

         The Company agrees to pay to the authenticating agent from time to time
such reasonable compensation for its services as shall be agreed upon in writing
between the Company and the authenticating agent.

         The provisions of Sections 8.02, 8.03, 8.04 and 9.03 and this Section
16.11 shall be applicable to any authenticating agent.

         Section 16.12. EXECUTION IN COUNTERPARTS. This Indenture may be
executed in any number of counterparts, each of which shall be an original, but
such counterparts shall together constitute but one and the same instrument.

         Section 16.13. SEVERABILITY. In case any provision in this Indenture or
in the Debentures shall be invalid, illegal or unenforceable, then (to the
extent permitted by law) the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby.

         The Bank of New York hereby accepts the trusts in this Indenture
declared and provided, upon the terms and conditions herein above set forth.


                                       87
<Page>

         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed.

                                  Aon CORPORATION


                                  By:  /s/ Patrick G. Ryan
                                       -----------------------------------------
                                       Name: Patrick G. Ryan
                                       Title: Chairman and Chief
                                               Executive Officer

                                  THE BANK OF NEW YORK, as Trustee


                                  By:  /s/ Van K. Brown
                                       -----------------------------------------
                                       Name:  Van K. Brown
                                       Title: Vice President
<Page>

                                     ANNEX 1

                          PROJECTED PAYMENT SCHEDULE(1)

<Table>
<Caption>
   QUARTERLY PERIOD ENDING        NONCONTINGENT PAYMENTS        CONTINGENT PAYMENTS       TOTAL PAYMENTS
   -----------------------        ----------------------        -------------------       --------------

<S>                             <C>                           <C>                     <C>
May 15, 2003                               18.28                        --                    18.28
November 15, 2003                          17.50                        --                    17.50
May 15, 2004                               17.50                        --                    17.50
November 15, 2004                          17.50                        --                    17.50
May 15, 2005                               17.50                        --                    17.50
November 15, 2005                          17.50                        --                    17.50
May 15, 2006                               17.50                        --                    17.50
November 15, 2006                          17.50                        --                    17.50
May 15, 2007                               17.50                        --                    17.50
November 15, 2007                          17.50                        --                    17.50
May 15, 2008                               17.50                        --                    17.50
November 15, 2008                          17.50                       13.97                  31.47
May 15, 2009                               17.50                       13.97                  31.47
November 15, 2009                          17.50                       13.97                  31.47
May 15, 2010                               17.50                       13.97                  31.47
November 15, 2010                          17.50                       13.97                  31.47
May 15, 2011                               17.50                       13.97                  31.47
November 15, 2011                          17.50                       13.97                  31.47
May 15, 2012                               17.50                       13.97                  31.47
November 14, 2012                           --                        1765.84                1765.84
</Table>


COMPARABLE YIELD:  9.1% COMPOUNDED SEMIANNUALLY

--------------------------------
         (1) The schedule of projected payments is determined on the basis of an
assumption of linear growth of the stock price and is not determined for any
purpose other than for the determination of interest accruals and adjustments
thereof in respect of the Debentures for United States federal income tax
purposes. The schedule of projected payments does not constitute a projection or
representation regarding the amounts payable on the Debentures.
<Page>

                                                                       EXHIBIT A

         [Include only for Global Debentures:]

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) (THE
"DEPOSITARY", WHICH TERM INCLUDES ANY SUCCESSOR DEPOSITARY FOR THE CERTIFICATES)
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 REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY (AND
ANY PAYMENT HEREIN IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY), 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.]

[Include only for Debentures that are Restricted Securities]

[THE DEBENTURE EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE UNITED STATES
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT AS SET FORTH
IN THE FOLLOWING SENTENCE. BY ITS ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS
THAT IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
SECURITIES ACT); (2) AGREES THAT IT WILL NOT, PRIOR TO EXPIRATION OF THE HOLDING
PERIOD APPLICABLE TO SALES OF THIS DEBENTURE UNDER RULE 144(K) UNDER THE
SECURITIES ACT (OR ANY SUCCESSOR PROVISION), RESELL OR OTHERWISE TRANSFER THIS
DEBENTURE OR THE COMMON STOCK ISSUABLE UPON CONVERSION OF THIS DEBENTURE EXCEPT
(A) TO AON CORPORATION OR ANY SUBSIDIARY THEREOF, (B) TO A QUALIFIED
INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C)
PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE
SECURITIES ACT (IF AVAILABLE) OR (D) PURSUANT TO A REGISTRATION STATEMENT WHICH
HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT (AND WHICH CONTINUES TO BE
EFFECTIVE AT THE TIME OF SUCH TRANSFER); (3) PRIOR TO SUCH TRANSFER (OTHER THAN
A TRANSFER PURSUANT TO CLAUSE (2)(D) ABOVE), IT WILL FURNISH TO THE BANK OF NEW
YORK, AS TRUSTEE (OR A SUCCESSOR TRUSTEE, AS APPLICABLE), SUCH CERTIFICATIONS,
LEGAL OPINIONS OR OTHER INFORMATION AS THE TRUSTEE MAY REASONABLY REQUIRE TO
CONFIRM THAT SUCH TRANSFER IS
<Page>

BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO,
THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT; AND (4) AGREES THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THIS DEBENTURE IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. THIS LEGEND WILL BE REMOVED UPON THE
EARLIER OF THE TRANSFER OF THE DEBENTURE EVIDENCED HEREBY PURSUANT TO CLAUSE
(2)(D) ABOVE OR UPON ANY TRANSFER OF THIS DEBENTURE UNDER RULE 144(K) UNDER THE
SECURITIES ACT (OR ANY SUCCESSOR PROVISION). THE INDENTURE CONTAINS A PROVISION
REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS DEBENTURE IN
VIOLATION OF THE FOREGOING RESTRICTION.]

THIS DEBENTURE WAS ISSUED WITH ORIGINAL ISSUE DISCOUNT FOR U.S. FEDERAL INCOME
TAX PURPOSES. FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL REVENUE
CODE, THE ISSUE PRICE OF EACH DEBENTURE IS $1,000 PER $1,000 OF PRINCIPAL
AMOUNT, THE ISSUE DATE IS NOVEMBER 7, 2002 AND THE COMPARABLE YIELD IS 9.1%,
COMPOUNDED SEMI-ANNUALLY. HOLDERS OF THIS DEBENTURE MAY OBTAIN INFORMATION
REGARDING THE AMOUNT OF ORIGINAL ISSUE DISCOUNT, YIELD TO MATURITY AND THE
PROJECTED PAYMENT SCHEDULE FOR THIS DEBENTURE BY SUBMITTING A WRITTEN REQUEST
FOR SUCH INFORMATION TO: AON CORPORATION, CORPORATE SECRETARY, 200 EAST RANDOLPH
STREET, CHICAGO, ILLINOIS 60601.


                                      A-2
<Page>

                                 AON CORPORATION

                  3 1/2 % CONVERTIBLE SENIOR DEBENTURE DUE 2012

                                                                CUSIP: 037389AQ6

No. 1                                                             $_____________

         Aon Corporation, a corporation duly organized and validly existing
under the laws of the State of Delaware (herein called the "COMPANY", which term
includes any successor corporation under the Indenture referred to on the
reverse hereof), for value received hereby promises to pay to CEDE & CO. or its
registered assigns, the principal sum of _____________ DOLLARS] [the principal
sum set forth on Schedule I hereto](2) on November 15, 2012 at the office or
agency of the Company maintained for that purpose in accordance with the terms
of the Indenture, in such coin or currency of the United States of America as at
the time of payment shall be legal tender for the payment of public and private
debts, and to pay interest, semiannually on May 15 and November 15 of each year,
commencing May 15, 2003, on said principal sum at said office or agency, in like
coin or currency, at the rate per annum of 3 1/2 %, from the May 15 or November
15, as the case may be, next preceding the date of this Debenture to which
interest has been paid or duly provided for, unless the date hereof is a date to
which interest has been paid or duly provided for, in which case from the date
of this Debenture, or unless no interest has been paid or duly provided for on
the Debentures, in which case from November 7, 2002 until payment of said
principal sum has been made or duly provided for. Notwithstanding the foregoing,
if the date hereof is after any May 1 or November 1, as the case may be, and
before the following May 15 or November 15, this Debenture shall bear interest
from such May 15 or November 15; PROVIDED that if the Company shall default in
the payment of interest due on such May 15 or November 15, then this Debenture
shall bear interest from the next preceding May 15 or November 15 to which
interest has been paid or duly provided for or, if no interest has been paid or
duly provided for on such Debenture, from November 7, 2002. Contingent interest,
if any, will accrue for any six month interest period and be payable to holders
of this Debenture on the last day of such six month interest period to the
person in whose name this Debenture is registered on the Debenture register at
the close of business on the day immediately preceding such day. Except as
otherwise provided in the Indenture, the interest payable on the Debenture
pursuant to the Indenture on any May 15 or November 15 will be paid to the
Person entitled thereto as it appears in the Debenture register at the close of
business on the record date, which shall be the May 1 or November 1 (whether or
not a Business Day) next preceding such May 15 or November 15, as provided in
the Indenture; PROVIDED that any such interest not punctually paid or duly
provided for shall be

-----------------------
       (2) For Global Debentures only.


                                      A-3
<Page>

payable as provided in the Indenture. The Company shall pay interest (i) on any
Debentures in certificated form by check mailed to the address of the Person
entitled thereto as it appears in the Debenture register or (ii) on any Global
Debenture by wire transfer of immediately available funds to the account of the
Depositary or its nominee.

         The Company promises to pay interest on overdue principal, premium, if
any, and (to the extent that payment of such interest is enforceable under
applicable law) interest at the rate of 4.5%, per annum.

         Reference is made to the further provisions of this Debenture set forth
on the reverse hereof, including, without limitation, provisions giving the
holder of this Debenture the right to convert this Debenture into Common Stock
of the Company on the terms and subject to the limitations referred to on the
reverse hereof and as more fully specified in the Indenture. Such further
provisions shall for all purposes have the same effect as though fully set forth
at this place.

         This Debenture shall be deemed to be a contract made under the laws of
the State of New York, and for all purposes shall be construed in accordance
with and governed by the laws of the State of New York, without regard to
conflicts of laws principles thereof.

         This Debenture shall not be valid or become obligatory for any purpose
until the certificate of authentication hereon shall have been manually signed
by the Trustee or a duly authorized authenticating agent under the Indenture.


                                      A-4
<Page>

         IN WITNESS WHEREOF, the Company has caused this Debenture to be duly
executed.

                                       Aon CORPORATION


                                       By:
                                          --------------------------------------


                                       By:
                                          --------------------------------------


TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Debentures described in the within-named Indenture.

THE BANK OF NEW YORK, as Trustee

By:
          --------------------------------------------
          Authorized Signatory


                                    , or


By:
          --------------------------------------------
          As Authenticating Agent
          (if different from Trustee)


        By:
                  -----------------------------------
                  Authorized Signatory


                                      A-5
<Page>

                          FORM OF REVERSE OF DEBENTURE

                                 Aon CORPORATION

                  3 1/2 % CONVERTIBLE SENIOR DEBENTURE DUE 2012

         This Debenture is one of a duly authorized issue of Debentures of
the Company, designated as its 3 1/2 % Convertible Senior Debentures Due 2012
(herein called the "DEBENTURES"), limited in aggregate principal amount to
$300,000,000, issued and to be issued under and pursuant to an Indenture
dated as of November 7, 2002 (herein called the "INDENTURE"), between the
Company and The Bank of New York, as trustee (herein called the "TRUSTEE"),
to which Indenture and all indentures supplemental thereto reference is
hereby made for a description of the rights, limitations of rights,
obligations, duties and immunities thereunder of the Trustee, the Company and
the holders of the Debentures.

         In case an Event of Default shall have occurred and be continuing, the
principal of, premium, if any, and accrued interest, including contingent
interest, if any, on all Debentures may be declared by either the Trustee or the
holders of not less than 25% in aggregate principal amount of the Debentures
then outstanding, and upon said declaration shall become, due and payable, in
the manner, with the effect and subject to the conditions provided in the
Indenture.

         The Indenture contains provisions permitting the Company and the
Trustee, with the consent of the holders of at least a majority in aggregate
principal amount of the Debentures at the time outstanding, to execute
supplemental indentures adding any provisions to or changing in any manner or
eliminating any of the provisions of the Indenture or of any supplemental
indenture or modifying in any manner the rights of the holders of the
Debentures; PROVIDED that no such supplemental indenture shall (i) extend the
fixed maturity of any Debenture, or reduce the rate or extend the time of
payment of interest, including contingent interest, if any, or Liquidated
Damages, if any, thereon, or reduce the principal amount thereof or premium, if
any, thereon, or reduce any amount payable upon redemption or repurchase
thereof, or impair the right of any Debentureholder to institute suit for the
payment thereof, or make the principal thereof or interest or premium, if any,
thereon payable in any coin or currency other than that provided in the
Debentures, or change the obligation of the Company to redeem any Debenture on a
redemption date in a manner adverse to the holders or change the obligation of
the Company to redeem any Debenture upon the happening of a Fundamental Change
in a manner adverse to the holder of the Debentures, or change the obligation of
the Company to repurchase any Debenture on a Repurchase Date in a manner adverse
to the holder of the Debentures, or impair the right to convert the Debentures
into Common Stock subject to the terms set forth in the Indenture, including
Section 15.06 thereof, without the consent of the holder of each Debenture so
affected, or modify any of the provisions of Section 11.02 or Section 7.07
thereof, except to increase any


                                      A-6
<Page>

such percentage or to provide that certain other provisions of the Indenture
cannot be modified or waived without the consent of the holder of each Debenture
so affected, or change any obligation of the Company to maintain an office or
agency in the places and for the purposes set forth in Section 5.01 thereof, or
reduce the quorum or voting requirements set forth in Article 10 or (ii) reduce
the aforesaid percentage of Debentures, the holders of which are required to
consent to any such supplemental indenture, without the consent of the holders
of all Debentures then outstanding. Subject to the provisions of the Indenture,
the holders of a majority in aggregate principal amount of the Debentures at the
time outstanding may on behalf of the holders of all of the Debentures waive any
past default or Event of Default under the Indenture and its consequences except
(A) a default in the payment of interest, or any premium on, or the principal
of, any of the Debentures, (B) a failure by the Company to convert any
Debentures into Common Stock of the Company, (C) a default in the payment of the
redemption price pursuant to Article 3 of the Indenture, (D) a default in the
payment of the repurchase price pursuant to Article 3 of the Indenture, or (E) a
default in respect of a covenant or provisions of the Indenture which under
Article 11 of the Indenture cannot be modified or amended without the consent of
the holders of each or all Debentures then outstanding or affected thereby. Any
such consent or waiver by the holder of this Debenture (unless revoked as
provided in the Indenture) shall be conclusive and binding upon such holder and
upon all future holders and owners of this Debenture and any Debentures which
may be issued in exchange or substitution hereof, irrespective of whether or not
any notation thereof is made upon this Debenture or such other Debentures.

         No reference herein to the Indenture and no provision of this Debenture
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of and any premium and
interest, including contingent interest, if any, on this Debenture at the place,
at the respective times, at the rate and in the coin or currency herein
prescribed.

         Interest on the Debentures shall be computed on the basis of a 360-day
year of twelve 30-day months.

         The Debentures are issuable in fully registered form, without coupons,
in denominations of $1,000 principal amount and any multiple of $1,000. At the
office or agency of the Company referred to on the face hereof, and in the
manner and subject to the limitations provided in the Indenture, without payment
of any service charge but with payment of a sum sufficient to cover any tax,
assessment or other governmental charge that may be imposed in connection with
any registration or exchange of Debentures, Debentures may be exchanged for a
like aggregate principal amount of Debentures of any other authorized
denominations.

         At any time on or after November 19, 2007 and prior to maturity, the
Debentures may be redeemed at the option of the Company, in whole or in part,
upon mailing a notice of such redemption not less than 30 days but not more than
60 days before the redemption date to the holders of Debentures at their last


                                      A-7
<Page>

registered addresses, all as provided in the Indenture, at the following
optional redemption prices (expressed as percentages of the principal amount),
together in each case with accrued and unpaid interest, including contingent
interest, if any, to, but excluding, the redemption date:

<Table>
<Caption>
REDEMPTION PERIOD                                                           REDEMPTION PRICE
-----------------                                                           ----------------
<S>                                                                       <C>
Beginning on November 19, 2007 and ending on November 14, 2008                     101.00%
Beginning on November 15, 2008 and ending on November 14, 2009                     100.50%
</Table>

and 100% if redeemed on or after November 15, 2009; PROVIDED that if the
redemption date is on a May 15 or November 15, then the interest payable on such
date shall be paid to the holder of record on the preceding May 1 or November 1,
respectively.

         The Company may not give notice of any redemption of the Debentures if
a default in the payment of interest, or premium, if any, on the Debentures has
occurred and is continuing.

         The Debentures are not subject to redemption through the operation of
any sinking fund.

         If a Fundamental Change occurs at any time prior to maturity of the
Debentures, this Debenture will be redeemable on a Fundamental Change Redemption
Date, 30 days after notice thereof, at the option of the holder of this
Debenture at a redemption price equal to 100% of the principal amount thereof,
together with accrued interest to (but excluding) the redemption date; PROVIDED
that if such Fundamental Change Redemption Date is a May 15 or November 15, the
interest payable on such date shall be paid to the holder of record of this
Debenture on the preceding May 1 or November 1, respectively. The Debentures
will be redeemable in multiples of $1,000 principal amount. The Company shall
mail to all holders of record of the Debentures a notice of the occurrence of a
Fundamental Change and of the redemption right arising as a result thereof on or
before the 10th day after the occurrence of such Fundamental Change. For a
Debenture to be so redeemed at the option of the holder, the Company must
receive at the office or agency of the Company maintained for that purpose in
accordance with the terms of the Indenture, such Debenture with the form
entitled "OPTION TO ELECT REPAYMENT UPON A FUNDAMENTAL CHANGE" on the reverse
thereof duly completed, together with such Debenture, duly endorsed for
transfer, on or before the 30th day after the date of such notice of a
Fundamental Change (or if such 30th day is not a Business Day, the immediately
succeeding Business Day).

         Subject to the terms and conditions of the Indenture, the Company shall
become obligated to purchase, at the option of the holder, all or any portion of
the Debentures held by such holder on November 15, 2009 in whole multiples of
$1,000 at a purchase price of 100% of the principal amount, plus any accrued and
unpaid interest, on such Debenture up to the Repurchase Date. To exercise such


                                      A-8
<Page>

right, a holder shall deliver to the Company such Debenture with the form
entitled "REPURCHASE NOTICE" on the reverse thereof duly completed, together
with the Debenture, duly endorsed for transfer, at any time from the opening of
business on the date that is 20 Business Days prior to such Repurchase Date
until the close of business on the Repurchase Date, and shall deliver the
Debentures to the Trustee (or other paying agent appointed by the Company) as
set forth in the Indenture.

         Holders have the right to withdraw any Repurchase Notice by delivering
to the Trustee (or other paying agent appointed by the Company) a written notice
of withdrawal up to the close of business on the Repurchase Date, all as
provided in the Indenture.

         If cash, sufficient to pay the purchase price of all Debentures or
portions thereof to be purchased as of the Repurchase Date is deposited with the
Trustee (or other paying agent appointed by the Company), on the Business Day
following the Repurchase Date, interest will cease to accrue on such Debentures
(or portions thereof) immediately after such Repurchase Date, and the holder
thereof shall have no other rights as such other than the right to receive the
purchase price upon surrender of such Debenture.

         Subject to the occurrence of certain events and in compliance with the
provisions of the Indenture, prior to the final maturity date of the Debentures,
the holder hereof has the right, at its option, to convert each $1,000 principal
amount of the Debentures into 46.5658 shares of the Company's Common Stock, as
such shares shall be constituted at the date of conversion and subject to
adjustment from time to time as provided in the Indenture, upon surrender of
this Debenture with the form entitled "CONVERSION NOTICE" on the reverse thereof
duly completed, to the Company at the office or agency of the Company maintained
for that purpose in accordance with the terms of the Indenture, or at the option
of such holder, the Corporate Trust Office, and, unless the shares issuable on
conversion are to be issued in the same name as this Debenture, duly endorsed
by, or accompanied by instruments of transfer in form satisfactory to the
Company duly executed by, the holder or by his duly authorized attorney. The
Company will notify the holder thereof of any event triggering the right to
convert the Debentures as specified above in accordance with the Indenture.

         No adjustment in respect of interest on any Debenture converted or
dividends on any shares issued upon conversion of such Debenture will be made
upon any conversion except as set forth in the next sentence. If this Debenture
(or portion hereof) is surrendered for conversion during the period from the
close of business on any record date for the payment of interest to the close of
business on the Business Day preceding the following interest payment date and
has not been called for redemption by the Company on a redemption date that
occurs during such period, this Debenture (or portion hereof being converted)
must be accompanied by payment, in immediately available funds or other funds
acceptable to the Company, of an amount equal to the interest otherwise payable


                                      A-9
<Page>

on such interest payment date on the principal amount being converted; PROVIDED
that no such payment shall be required if there shall exist at the time of
conversion a default in the payment of interest, including contingent interest,
if any, on the Debentures.

         No fractional shares will be issued upon any conversion, but an
adjustment and payment in cash will be made, as provided in the Indenture, in
respect of any fraction of a share which would otherwise be issuable upon the
surrender of any Debenture or Debentures for conversion.

         A Debenture in respect of which a holder is exercising its right to
require redemption upon a Fundamental Change or repurchase on a Repurchase Date
may be converted only if such holder withdraws its election to exercise either
such right in accordance with the terms of the Indenture.

         Any Debentures called for redemption, unless surrendered for conversion
by the holders thereof on or before the close of business on the Business Day
preceding the redemption date, may be deemed to be redeemed from the holders of
such Debentures for an amount equal to the applicable redemption price, together
with accrued but unpaid interest to, but excluding, the date fixed for
redemption, by one or more investment banks or other purchasers who may agree
with the Company (i) to purchase such Debentures from the holders thereof and
convert them into shares of the Company's Common Stock and (ii) to make payment
for such Debentures as aforesaid to the Trustee in trust for the holders.

         Upon due presentment for registration of transfer of this Debenture at
the office or agency of the Company maintained for that purpose in accordance
with the terms of the Indenture, a new Debenture or Debentures of authorized
denominations for an equal aggregate principal amount will be issued to the
transferee in exchange thereof, subject to the limitations provided in the
Indenture, without charge except for any tax, assessment or other governmental
charge imposed in connection therewith.

         The Company, the Trustee, any authenticating agent, any paying agent,
any conversion agent and any Debenture registrar may deem and treat the
registered holder hereof as the absolute owner of this Debenture (whether or not
this Debenture shall be overdue and notwithstanding any notation of ownership or
other writing hereon made by anyone other than the Company or any Debenture
registrar) for the purpose of receiving payment hereof, or on account hereof,
for the conversion hereof and for all other purposes, and neither the Company
nor the Trustee nor any other authenticating agent nor any paying agent nor
other conversion agent nor any Debenture registrar shall be affected by any
notice to the contrary. All payments made to or upon the order of such
registered holder shall, to the extent of the sum or sums paid, satisfy and
discharge liability for monies payable on this Debenture.


                                      A-10
<Page>

         No recourse for the payment of the principal of or any premium or
interest on this Debenture, or for any claim based hereon or otherwise in
respect hereof, and no recourse under or upon any obligation, covenant or
agreement of the Company in the Indenture or any supplemental indenture or in
any Debenture, or because of the creation of any indebtedness represented
thereby, shall be had against any incorporator, stockholder, employee, agent,
officer or director or subsidiary, as such, past, present or future, of the
Company or of any successor corporation, either directly or through the Company
or any successor corporation, whether by virtue of any constitution, statute or
rule of law or by the enforcement of any assessment or penalty or otherwise, all
such liability being, by acceptance hereof and as part of the consideration for
the issue hereof, expressly waived and released.

         This Debenture shall be deemed to be a contract made under the laws of
New York, and for all purposes shall be construed in accordance with the laws of
New York, without regard to conflicts of laws principles thereof.

         Terms used in this Debenture and defined in the Indenture are used
herein as therein defined.


                                      A-11
<Page>

                                  ABBREVIATIONS

         The following abbreviations, when used in the inscription of the face
of this Debenture, shall be construed as though they were written out in full
according to applicable laws or regulations.

<Table>
<S>             <C>                                          <C>
TEN COM -         as tenants in common                        UNIF GIFT MIN ACT -___ Custodian ___
TEN ENT -         as tenant by the entireties                 (Cust)   (Minor)
JT TEN -          as joint tenants with right of
                  survivorship and not as                     under Uniform Gifts to Minors Act
                  tenants in common                           ____________________________
                                                                        (State)
</Table>

         Additional abbreviations may also be used though not in the above list.
<Page>

                                CONVERSION NOTICE

TO:      Aon CORPORATION
         THE BANK OF NEW YORK

         The undersigned registered owner of this Debenture hereby irrevocably
exercises the option to convert this Debenture, or the portion thereof (which is
$1,000 or a multiple thereof) below designated, into shares of Common Stock of
Aon Corporation in accordance with the terms of the Indenture referred to in
this Debenture, and directs that the shares issuable and deliverable upon such
conversion, together with any check in payment for fractional shares and any
Debentures representing any unconverted principal amount hereof, be issued and
delivered to the registered holder hereof unless a different name has been
indicated below. Capitalized terms used herein but not defined shall have the
meanings ascribed to such terms in the Indenture. If shares or any portion of
this Debenture not converted are to be issued in the name of a person other than
the undersigned, the undersigned will provide the appropriate information below
and pay all transfer taxes payable with respect thereto. Any amount required to
be paid by the undersigned on account of interest, including contingent
interest, if any, accompanies this Debenture.

Dated:
       ----------------------

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

                                    -------------------------------------------
                                    Signature(s)


                                    Signature(s) must be guaranteed by an
                                    "ELIGIBLE GUARANTOR INSTITUTION" meeting the
                                    requirements of the Debenture 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 Debenture registrar in
                                    addition to, or in substitution for, STAMP,
                                    all in accordance with the Securities
                                    Exchange Act of 1934, as amended.

                                    -------------------------------------------
                                    Signature Guarantee
<Page>

         Fill in the registration of shares of Common Stock if to be issued, and
Debentures if to be delivered, other than to and in the name of the registered
holder:

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


--------------------------------------
(Street Address)


--------------------------------------
(City, State and Zip Code)


--------------------------------------
Please print name and address

Principal amount to be converted (if less than all):

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


Social Security or Other Taxpayer
 Identification Number:


--------------------------------------
<Page>

                           OPTION TO ELECT REDEMPTION
                           UPON A FUNDAMENTAL CHANGE

TO:      Aon CORPORATION
         THE BANK OF NEW YORK

         The undersigned registered owner of this Debenture hereby irrevocably
acknowledges receipt of a notice from Aon Corporation (the "COMPANY") as to the
occurrence of a Fundamental Change with respect to the Company and requests and
instructs the Company to redeem the entire principal amount of this Debenture,
or the portion thereof (which is $1,000 or a multiple thereof) below designated,
in accordance with the terms of the Indenture referred to in this Debenture at
the price of 100% of such entire principal amount or portion thereof, together
with accrued interest to, but excluding, the Fundamental Change Redemption Date,
to the registered holder hereof. Capitalized terms used herein but not defined
shall have the meanings ascribed to such terms in the Indenture.

Dated:
       ----------------------

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

                                    -------------------------------------------
                                    Signature(s)


                                    NOTICE: The above signatures of the
                                    holder(s) hereof must correspond with the
                                    name as written upon the face of the
                                    Debenture in every particular without
                                    alteration or enlargement or any change
                                    whatever.

                                    Principal amount to be repaid (if less than
                                    all):

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

                                    -------------------------------------------
                                    Social Security or Other Taxpayer
                                    Identification Number
<Page>

                                REPURCHASE NOTICE

TO:      Aon CORPORATION
         THE BANK OF NEW YORK

         The undersigned registered owner of this Debenture hereby irrevocably
acknowledges receipt of a notice from (the "COMPANY") regarding the right of
holders to elect to require the Company to repurchase the Debentures and
requests and instructs the Company to repay the entire principal amount of this
Debenture, or the portion thereof (which is $1,000 or an integral multiple
thereof) below designated, in accordance with the terms of the Indenture at the
price of 100% of such entire principal amount or portion thereof, together with
accrued interest to, by excluding, the Repurchase Date, to the registered holder
hereof. Capitalized terms used herein but not defined shall have the meanings
ascribed to such terms in the Indenture. The Debentures shall be repurchased by
the Company as of the Repurchase Date pursuant to the terms and conditions
specified in the Indenture. If the Company elects to pay the purchase price, in
whole or in part, in shares of Common Stock but such portion of the purchase
price shall ultimately be paid to such holder entirely in cash because any of
the conditions to payment of the purchase price in shares of Common Stock is not
satisfied prior to the close of business on the applicable Repurchase Date, the
undersigned registered owner elects:

[ ] to withdraw this Repurchase Notice as to $[ ] principal amount of the
Debentures to which this Repurchase Notice relates (Certificate Numbers: ), or

[ ] to receive cash in respect of $[ ] principal amount of the Debentures to
which this Repurchase Notice relates.

         Dated:

         Signature(s):

         NOTICE: The above signatures of the holder(s) hereof must correspond
with the name as written upon the face of the Debenture in every particular
without alteration or enlargement or any change whatever.

         Debenture Certificate Number (if applicable):

         Principal amount to be repurchased (if less than all):

         Social Security or Other Taxpayer Identification Number:
<Page>

                                   ASSIGNMENT

         For value received ______________________________hereby sell(s)
assign(s) and transfer(s) unto ___________________________________ (Please
insert social security or other Taxpayer Identification Number of assignee) the
within Debenture, and hereby irrevocably constitutes and appoints
______________________________________ attorney to transfer said Debenture on
the books of the Company, with full power of substitution in the premises.

         In connection with any transfer of the Debenture prior to the
expiration of the holding period applicable to sales thereof under Rule 144(k)
under the Securities Act (or any successor provision) (other than any transfer
pursuant to a registration statement that has been declared effective under the
Securities Act), the undersigned confirms that such Debenture is being
transferred:

            / /   To Aon Corporation or a subsidiary thereof; or

            / /   To a "QUALIFIED INSTITUTIONAL BUYER" in compliance with Rule
                  144A under the Securities Act of 1933, as amended; or

            / /   Pursuant to and in compliance with Rule 144 under the
                  Securities Act of 1933, as amended; or

            / /   Pursuant to a Registration Statement which has been declared
                  effective under the Securities Act of 1933, as amended, and
                  which continues to be effective at the time of transfer;

and unless the Debenture has been transferred to Aon Corporation or a subsidiary
thereof, the undersigned confirms that such Debenture is not being transferred
to an "AFFILIATE" of the Company as defined in Rule 144 under the Securities Act
of 1933, as amended.

         UNLESS ONE OF THE BOXES IS CHECKED, THE TRUSTEE WILL REFUSE TO REGISTER
ANY OF THE DEBENTURES EVIDENCED BY THIS CERTIFICATE IN THE NAME OF ANY PERSON
OTHER THAN THE REGISTERED HOLDER THEREOF.

Dated:
       ----------------------

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

                                    --------------------------------------------
                                    Signature(s)

                                    Signature(s) must be guaranteed by an
                                    "ELIGIBLE GUARANTOR INSTITUTION"
<Page>

                                    meeting the requirements of the Debenture
                                    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 Debenture
                                    registrar in addition to, or in substitution
                                    for, STAMP, al in accordance with the
                                    Securities Exchange Act of 1934, as amended.

                                    --------------------------------------------
                                    Signature Guarantee

                  NOTICE: The signature on the Conversion Notice, the Option to
                  Elect Redemption Upon a Fundamental Change, the Repurchase
                  Notice or the Assignment must correspond with the name as
                  written upon the face of the Debenture in every particular
                  without alteration or enlargement or any change whatever.
<Page>

                                                                      Schedule I

                [Include Schedule I only for a Global Debenture]


                                 AON CORPORATION
                  3 1/2 % Convertible Senior Debenture Due 2012

No.  _______

<Table>
<Caption>

=========== ======================================== ===================================== =========================
                                                     Notation Explaining Principal         Authorized Signature of
Date        Principal Amount                         Amount Recorded                       Trustee or Custodian
----------- ---------------------------------------- ------------------------------------- -------------------------
<S>         <C>                                      <C>                                  <C>

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</Table>