<PAGE>   1
                                                                     EXHIBIT 4.1
                                                                     -----------

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

                            SKY FINANCIAL GROUP, INC.


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



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


                                    INDENTURE

                           Dated as of March 31, 2000

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




                            WILMINGTON TRUST COMPANY,

                              as Debenture Trustee


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



               JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES


<PAGE>   2




                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                          Page
                                                                                          ----
                                         ARTICLE I
                                        DEFINITIONS

<S>                                                                                         <C>
SECTION 1.01  Definitions....................................................................1
SECTION 1.02  Business Day Certificate......................................................11

                                        ARTICLE II
                                        SECURITIES

SECTION 2.01  Forms Generally...............................................................12
SECTION 2.02  Execution and Authentication..................................................12
SECTION 2.03  Form and Payment..............................................................12
SECTION 2.04  Legends.......................................................................13
SECTION 2.05  Global Security...............................................................13
SECTION 2.06  Interest......................................................................14
SECTION 2.07  Transfer and Exchange.........................................................15
SECTION 2.08  Replacement Securities........................................................17
SECTION 2.09  Temporary Securities..........................................................17
SECTION 2.10  Cancellation..................................................................18
SECTION 2.11  Defaulted Interest............................................................18
SECTION 2.12  CUSIP Numbers.................................................................19

                                        ARTICLE III
                          PARTICULAR COVENANTS OF THE CORPORATION

SECTION 3.01  Payment of Principal and Interest.............................................19
SECTION 3.02  Offices for Notices and Payments, etc.........................................19
SECTION 3.03  Appointments to Fill Vacancies in Debenture Trustee's Office..................20
SECTION 3.04  Provision as to Paying Agent..................................................20
SECTION 3.05  Certificate to Debenture Trustee..............................................21
SECTION 3.06  Compliance with Consolidation Provisions......................................21
SECTION 3.07  Limitation on Dividends.......................................................21
SECTION 3.08  Covenants as to Sky Financial Capital Trust I.................................22
SECTION 3.09  Payment of Expenses...........................................................22
SECTION 3.10  Payment Upon Resignation or Removal...........................................23

                                        ARTICLE IV
                            LIST OF SECURITYHOLDERS AND REPORTS
                       BY THE CORPORATION AND THE DEBENTURE TRUSTEE

SECTION 4.01  List of Securityholders.......................................................23
SECTION 4.02  Preservation and Disclosure of Lists..........................................24
SECTION 4.03  Reports by the Corporation....................................................25
SECTION 4.04  Reports by the Debenture Trustee..............................................26
</TABLE>

                                       -i-
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<TABLE>
<CAPTION>
                                         ARTICLE V
                             REMEDIES OF THE DEBENTURE TRUSTEE
                         AND SECURITYHOLDERS UPON EVENT OF DEFAULT

<S>                                                                                        <C>
SECTION 5.01  Events of Default.............................................................26
SECTION 5.02  Payment of Securities on Default; Suit Therefor...............................28
SECTION 5.03  Application of Moneys Collected by Debenture Trustee..........................30
SECTION 5.04  Proceedings by Securityholders................................................30
SECTION 5.05  Proceedings by Debenture Trustee..............................................31
SECTION 5.06  Remedies Cumulative and Continuing............................................31
SECTION 5.07  Direction of Proceedings and Waiver of Defaults by Majority of
                    Securityholders.........................................................32
SECTION 5.08  Notice of Defaults............................................................33
SECTION 5.09  Undertaking to Pay Costs......................................................33

                                        ARTICLE VI
                             CONCERNING THE DEBENTURE TRUSTEE

SECTION 6.01  Duties and Responsibilities of Debenture Trustee..............................34
SECTION 6.02  Reliance on Documents, Opinions, etc..........................................35
SECTION 6.03  No Responsibility for Recitals, etc...........................................36
SECTION 6.04  Debenture Trustee, Authenticating Agent, Paying Agents, Transfer
                    Agents and Registrar May Own Securities.................................37
SECTION 6.05  Moneys to be Held in Trust....................................................37
SECTION 6.06  Compensation and Expenses of Debenture Trustee................................38
SECTION 6.07  Officers' Certificate as Evidence.............................................38
SECTION 6.08  Conflicting Interest of Debenture Trustee.....................................38
SECTION 6.09  Eligibility of Debenture Trustee..............................................39
SECTION 6.10  Resignation or Removal of Debenture Trustee...................................40
SECTION 6.11  Acceptance by Successor Debenture Trustee.....................................40
SECTION 6.12  Succession by Merger, etc.....................................................41
SECTION 6.13  Limitation on Rights of Debenture Trustee as a Creditor.......................41
SECTION 6.14  Authenticating Agents.........................................................

                                        ARTICLE VII
                              CONCERNING THE SECURITYHOLDERS

SECTION 7.01  Action by Securityholders.....................................................42
SECTION 7.02  Proof of Execution by Securityholders.........................................43
SECTION 7.03  Who Are Deemed Absolute Owners................................................43
SECTION 7.04  Securities Owned by Corporation Deemed Not Outstanding........................43
SECTION 7.05  Revocation of Consents; Future Holders Bound..................................44
</TABLE>

                                      -ii-

<PAGE>   4

<TABLE>
<CAPTION>
                                       ARTICLE VIII
                                MEETINGS OF SECURITYHOLDERS

<S>                                                                                        <C>
SECTION 8.01  Purposes of Meetings..........................................................44
SECTION 8.02  Call of Meetings by Debenture Trustee.........................................45
SECTION 8.03  Call of Meetings by Corporation or Securityholders............................45
SECTION 8.04  Qualifications for Voting.....................................................45
SECTION 8.05  Regulations...................................................................45
SECTION 8.06  Voting........................................................................46

                                        ARTICLE IX
                                        AMENDMENTS

SECTION 9.01  Without Consent of Securityholders............................................47
SECTION 9.02  With Consent of Securityholders...............................................48
SECTION 9.03  Compliance with Trust Indenture Act; Effect of Supplemental Indentures........49
SECTION 9.04  Notation on Securities........................................................49
SECTION 9.05  Evidence of Compliance of Supplemental Indenture to be Furnished to
                    Debenture Trustee.......................................................49

                                         ARTICLE X
                CONSOLIDATION, MERGER, SALE, CONVEYANCE, TRANSFER AND LEASE

SECTION 10.01  Corporation May Consolidate, etc., on Certain Terms..........................50
SECTION 10.02  Successor Person to be Substituted for Corporation...........................50
SECTION 10.03  Opinion of Counsel to be Given Debenture Trustee.............................51

                                        ARTICLE XI
                          SATISFACTION AND DISCHARGE OF INDENTURE

SECTION 11.01  Discharge of Indenture.......................................................51
SECTION 11.02  Deposited Moneys and U.S. Government Obligations to be Held in
                      Trust by Debenture Trustee............................................52
SECTION 11.03  Paying Agent to Repay Moneys Held............................................52
SECTION 11.04  Return of Unclaimed Moneys...................................................52
SECTION 11.05  Defeasance Upon Deposit of Moneys or U.S. Government Obligations.............52

                                        ARTICLE XII
                         IMMUNITY OF INCORPORATORS, STOCKHOLDERS,
                                  OFFICERS AND DIRECTORS

SECTION 12.01  Indenture and Securities Solely Corporate Obligations........................54
</TABLE>

                                     -iii-
<PAGE>   5

<TABLE>
<CAPTION>
                                       ARTICLE XIII
                                 MISCELLANEOUS PROVISIONS

<S>                                                                                        <C>
SECTION 13.01  Successors...................................................................54
SECTION 13.02  Official Acts by Successor Corporation.......................................54
SECTION 13.03  Surrender of Corporation Powers..............................................55
SECTION 13.04  Addresses for Notices, etc...................................................55
SECTION 13.05  Governing Law................................................................55
SECTION 13.06  Evidence of Compliance with Conditions Precedent.............................55
SECTION 13.07  Business Days................................................................56
SECTION 13.08  Trust Indenture Act to Control...............................................56
SECTION 13.09  Table of Contents, Headings, etc.............................................56
SECTION 13.10  Execution in Counterparts....................................................56
SECTION 13.11  Separability.................................................................56
SECTION 13.12  Assignment...................................................................57
SECTION 13.13  Acknowledgment of Rights.....................................................57

                                        ARTICLE XIV
                                 PREPAYMENT OF SECURITIES

SECTION 14.01  Special Event Prepayment.....................................................57
SECTION 14.02  Optional Prepayment by Corporation...........................................57
SECTION 14.03  No Sinking Fund..............................................................59
SECTION 14.04  Notice of Prepayment; Selection of Securities................................59
SECTION 14.05  Payment of Securities Called for Prepayment..................................59

                                        ARTICLE XV
                                SUBORDINATION OF SECURITIES

SECTION 15.01  Agreement to Subordinate.....................................................60
SECTION 15.02  Default on Senior Indebtedness...............................................60
SECTION 15.03  Liquidation; Dissolution; Bankruptcy.........................................61
SECTION 15.04  Subrogation..................................................................62
SECTION 15.05  Debenture Trustee to Effectuate Subordination................................63
SECTION 15.06  Notice by the Corporation....................................................63
SECTION 15.07  Rights of the Debenture Trustee; Holders of Senior Indebtedness..............64
SECTION 15.08  Subordination May Not Be Impaired............................................65

                                        ARTICLE XVI
                           EXTENSION OF INTEREST PAYMENT PERIOD

SECTION 16.01  Extension of Interest Payment Period.........................................65
SECTION 16.02  Notice of Extension..........................................................66
</TABLE>

                                      -iv-
<PAGE>   6

TESTIMONIUM

SIGNATURES

EXHIBIT A

                                      -v-
<PAGE>   7



         Tie Sheet of provisions of Trust Indenture Act of 1939 with Indenture
dated as of March 31, 2000 between Sky Financial Group, Inc. and Wilmington
Trust Company, as Debenture Trustee:

<TABLE>
<CAPTION>
         ACT SECTION                                                                        INDENTURE SECTION

<S>                      <C>
         310(a)(1)....................................................................................6.09
            (a)(2)........................................................................6.09, 6.10, 6.11
         310(a)(3).....................................................................................N/A
            (a)(4).....................................................................................N/A
         310(a)(5)........................................................................6.09, 6.10, 6.11
         310(b)................................................................................       6.08
         310(c).................................................................................       N/A
         311(a)................................................................................       6.13
         311(b)................................................................................       6.13
         311(c).................................................................................       N/A
         312(a)........................................................................4.01(a) and 4.02(a)
         312(b)            4.02(b)
         312(c)            4.02(c)
         313(a)....................................................................................4.04(a)
         313(b)(1).................................................................................4.04(a)
         313(b)(2).................................................................................4.04(a)
         313(c)....................................................................................4.04(a)
         313(d)....................................................................................4.04(b)
         314(a).................................................................................3.05, 4.03
         314(b)........................................................................................N/A
         314(c)(1)..........................................................................6.07 and 13.06
         314(c)(2)..........................................................................6.07 and 13.06
         314(c)(3).....................................................................................N/A
         314(d)........................................................................................N/A
         314(e)................................................................................6.07, 13.06
         314(f)........................................................................................N/A
         315(a)(c) and (d)............................................................................6.01
         315(b).......................................................................................5.08
         315(e).......................................................................................5.09
         316(a)(1)....................................................................................5.07
         316(a)(2).....................................................................................N/A
         316(a) last sentence.........................................................................9.02
         316(b)..............................................................................5.07 and 9.02
         316(c)..............................................................................7.01 and 9.02
         317(a).......................................................................................5.05
         317(b).......................................................................................6.05
         318.........................................................................................13.08
</TABLE>
----------------
THIS TIE-SHEET IS NOT PART OF THE INDENTURE AS EXECUTED.

                                      -vi-

<PAGE>   8

                                    INDENTURE

         THIS INDENTURE, dated as of March 31, 2000, between Sky Financial
Group, Inc., an Ohio corporation (hereinafter called the "Corporation"), and
Wilmington Trust Company, a Delaware banking corporation, as debenture trustee
(hereinafter sometimes called the "Debenture Trustee").

                              W I T N E S S E T H :

         In consideration of the premises, and the purchase of the Securities
(as defined below) by the holders thereof, the Corporation covenants and agrees
with the Debenture Trustee for the equal and proportionate benefit of the
respective holders from time to time of the Securities, as follows:


                                    ARTICLE I
                                   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 shall have the respective meanings
specified in this Section 1.01. All other terms used in this Indenture which are
defined in the Trust Indenture Act of 1939, as amended (the "Trust Indenture
Act"), or which are by reference therein defined in the Securities Act of 1933,
as amended (the "Securities Act"), shall (except as herein otherwise expressly
provided or unless the context otherwise requires) have the meanings assigned to
such terms in said Trust Indenture Act and in said Securities Act as in force at
the date of this Indenture as originally executed. The following terms have the
meanings given to them in the Declaration: (i) Clearing Agency; (ii) Delaware
Trustee; (iii) Property Trustee; (iv) Administrative Trustees; (v) Series A
Capital Securities; (vi) Series B Capital Securities; (vii) Direct Action;
(viii) Series A Capital Securities Guarantee; (ix) Series B Capital Securities
Guarantee; (x) Distributions; and (xi) Initial Purchaser. All accounting terms
used herein and not expressly defined shall have the meanings assigned to such
terms in accordance with generally accepted accounting principles, and the term
"generally accepted accounting principles" means such accounting principles as
are generally accepted at the time of any computation. The words "herein,"
"hereof" and "hereunder" and other words of similar import refer to this
Indenture as a whole and not to any particular Article, Section or other
subdivision. Headings are used for convenience of reference only and do not
affect interpretation. The singular includes the plural and vice versa.

         "Additional Sums" shall have the meaning set forth in Section 2.06(c).

         "Adjusted Treasury Rate" means, with respect to any prepayment date
pursuant to Section 14.01, the rate per annum equal to (i) the yield, under the
heading which represents the average for the immediately prior week, appearing
in the most recently published statistical release designated "H.15 (519)" or
any successor publication which is published weekly by the Federal Reserve and
which establishes yields on actively traded United States Treasury securities

                                       1

<PAGE>   9

adjusted to constant maturity under the caption "Treasury Constant Maturities,"
for the maturity corresponding to the Remaining Life (if no maturity is within
three months before or three months after the maturity corresponding to the
Remaining Life, yields for the two published maturities most closely
corresponding to the Remaining Life shall be determined, and the Adjusted
Treasury Rate shall be interpolated or extrapolated from such yields on a
straight-line basis, rounding to the nearest month) or (ii) if such release (or
any successor release) is not published during the week preceding the
calculation date or does not contain such yields, the rate per annum equal to
the semi-annual equivalent yield to maturity of the Comparable Treasury Issue,
calculated using a price for the Comparable Treasury Issue (expressed as a
percentage of its principal amount) equal to the Comparable Treasury Price for
such prepayment date, in each case calculated on the third Business Day
preceding the prepayment date, plus 281 basis points.

         "Affiliate" shall have the meaning given to that term in Rule 405 under
the Securities Act or any successor rule thereunder.

         "Allocable Amounts," when used with respect to any Senior Indebtedness,
means all amounts due or to become due on such Senior Indebtedness less, if
applicable, any amount which would have been paid to, and retained by, the
holders of such Senior Indebtedness (whether as a result of the receipt of
payments by the holders of such Senior Indebtedness from the Corporation or any
other obligor thereon or from any holders of, or trustee in respect of, other
indebtedness that is subordinate and junior in right of payment to such Senior
Indebtedness pursuant to any provision of such indebtedness for the payment over
of amounts received on account of such indebtedness to the holders of such
Senior Indebtedness or otherwise) but for the fact that such Senior Indebtedness
is subordinate or junior in right of payment to (or subject to a requirement
that amounts received on such Senior Indebtedness be paid over to obligees on)
trade accounts payable or accrued liabilities arising in the ordinary course of
business.

         "Authenticating Agent" shall mean any agent or agents of the Debenture
Trustee which at the time shall be appointed and acting pursuant to Section
6.14.

         "Bankruptcy Law" shall mean Title 11, U.S. Code, or any similar federal
or state law for the relief of debtors.

         "Board of Directors" shall mean either the Board of Directors of the
Corporation or any duly authorized committee of that board.

         "Board Resolution" shall mean a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Corporation to have been duly adopted
by the Board of Directors and to be in full force and effect on the date of such
certification, and delivered to the Debenture Trustee.

         "Book-Entry Capital Securities" shall have the meaning set forth in
Section 2.05(a)(i).

         "Business Day" shall mean, with respect to any series of Securities,
any day other than a Saturday, a Sunday or a day on which banking institutions
in Wilmington, Delaware, New York,



                                       2
<PAGE>   10

New York or Bowling Green, Ohio are authorized or required by law or executive
order to remain closed.

         "Capital Securities" shall mean undivided beneficial interests in the
assets of the Trust which are designated as "Capital Securities" and rank pari
passu with the Common Securities issued by the Trust; PROVIDED, HOWEVER, that if
an Event of Default has occurred and is continuing, no payments in respect of
Distributions on, or payments upon liquidation, redemption or otherwise with
respect to, the Common Securities shall be made until the holders of the Capital
Securities shall be paid in full the Distributions and the liquidation,
redemption and other payments to which they are entitled. References to "Capital
Securities"' shall include collectively any Series A Capital Securities and
Series B Capital Securities.

         "Capital Securities Guarantee" shall mean any guarantee agreement that
the Corporation may enter into with Wilmington Trust Company or other Persons
that operates directly or indirectly for the benefit of holders of Capital
Securities and shall include the Series A Capital Securities Guarantee and the
Series B Capital Securities Guarantee with respect to the Series A Capital
Securities and the Series B Capital Securities, respectively.

         "Commission" shall mean 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 Securities" shall mean undivided beneficial interests in the
assets of the Trust which are designated as "Common Securities" and rank pari
passu with Capital Securities issued by the Trust; PROVIDED, HOWEVER, that if an
Event of Default has occurred and is continuing, no payments in respect of
Distributions on, or payments upon liquidation, redemption or otherwise with
respect to, the Common Securities shall be made until the holders of the Capital
Securities shall be paid in full the Distributions and the liquidation,
redemption and other payments to which they are then entitled.

         "Common Securities Guarantee" shall mean any guarantee that the
Corporation may enter into that operates directly or indirectly for the benefit
of holders of Common Securities.

         "Common Stock" shall mean the common shares, without par value, of the
Corporation or any other class of stock resulting from changes or
reclassifications of such Common Stock consisting solely of changes in par
value, or from par value to no par value, or from no par value to par value.

         "Comparable Treasury Issue" shall mean the United States Treasury
security selected by the Quotation Agent as having a maturity comparable to the
Remaining Life of the Securities that would be utilized, at the time of
selection and in accordance with customary financial practice, in pricing new
issues of corporate debt securities of comparable maturity to the Remaining Life
of the Securities, provided that if no United States Treasury security has a
maturity which is within a period from three months before to three months after
the Remaining Life, the two most closely corresponding United States Treasury
securities as selected by the



                                       3
<PAGE>   11

Quotation Agent shall be used as the Comparable Treasury Issue, and the Adjusted
Treasury Rate shall be interpolated or extrapolated on a straight-line basis,
rounding to the nearest month, using such securities.

         "Comparable Treasury Price" shall mean, with respect to any prepayment
date pursuant to Section 14.01, (i) the average of three Reference Treasury
Dealer Quotations for such prepayment date, after excluding the highest and
lowest Reference Treasury Dealer Quotations, or (ii) if the Quotation Agent
obtains fewer than five such Reference Treasury Dealer Quotations, the average
of all such Reference Treasury Dealer Quotations.

         "Compounded Interest" shall have the meaning set forth in Section
16.01.

         "Corporation" shall mean the person identified as "Corporation" in the
preamble to this Indenture and, subject to the provisions of Article X, shall
also include its successors and assigns.

         "Corporation Request" or "Corporation Order" shall mean a written
request or order signed in the name of the Corporation by an Officer and
delivered to the Debenture Trustee.

         "Coupon Rate" shall have the meaning set forth in Section 2.06(a).

         "Custodian" shall mean any receiver, trustee, assignee, liquidator, or
similar official under any Bankruptcy Law.

         "Debenture Trustee" shall mean the Person identified as "Debenture
Trustee" in the preamble to this Indenture and, subject to the provisions of
Article VI hereof, shall also include its successors and assigns.

         "Declaration" shall mean the Amended and Restated Declaration of Trust
of the Trust, dated as of March 31, 2000, by and among the Trustees (as defined
therein), the Corporation, as sponsor, and the holders from time to time of
undivided beneficial interest in the assets of the Trust, as amended from time
to time.

         "Default" shall mean any event, act or condition that with notice or
lapse of time, or both, would constitute an Event of Default.

         "Defaulted Interest" shall have the meaning set forth in Section 2.11.

         "Deferred Interest" shall have the meaning set forth in Section 16.01.

         "Definitive Securities" shall mean those securities issued in fully
registered certificated form not otherwise in global form.

         "Depositary" shall mean, with respect to the Securities for which the
Corporation shall determine that such Securities will be issued as a Global
Security, The Depository Trust Company, New York, New York, or another clearing
agency, or any successor registered as a



                                       4
<PAGE>   12

clearing agency pursuant to Section 17A of the Exchange Act or other applicable
statute or regulation, which, in each case, shall be designated by the
Corporation pursuant to Section 2.05(d).

         "Dissolution Event" shall mean any event resulting in the dissolution
of the Trust pursuant to the Declaration, and the distribution of the Securities
held by the Property Trustee to the holders of the Trust Securities issued by
the Trust pro rata in accordance with the Declaration.

         "Event of Default" shall mean any event specified in Section 5.01,
continued for the period of time, if any, and after the giving of the notice, if
any, therein designated.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended.

         "Exchange Offer" shall mean the offer that may be made pursuant to the
Registration Rights Agreement (i) by the Corporation to exchange the Exchange
Securities for the Initial Securities and to execute the Series B Capital
Securities Guarantee in respect of the Series B Capital Securities and (ii) by
the Trust to exchange the Series B Capital Securities for the Series A Capital
Securities.

         "Exchange Securities" shall mean the Corporation's 9.34% Junior
Subordinated Deferrable Interest Debentures due May 1, 2030, Series B, as
authenticated and issued under this Indenture.

         "Extended Interest Payment Period" shall have the meaning set forth in
Section 16.01.

         "Federal Reserve" shall mean the Board of Governors of the Federal
Reserve System.

         "Global Security" shall mean, with respect to the Securities, a
Security executed by the Corporation and delivered by the Debenture Trustee to
the Depositary or pursuant to the Depositary's instruction, or if no
instructions are received then held by the Property Trustee, all in accordance
with this Indenture, which Security shall be registered in the name of the
Depositary or its nominee.

         "Indebtedness" shall mean, whether recourse as to all or a portion of
the assets of the Corporation and whether or not contingent, (i) every
obligation of the Corporation for money borrowed; (ii) every obligation of the
Corporation evidenced by bonds, debentures, notes or other similar instruments,
including obligations incurred in connection with the acquisition of property,
assets or businesses; (iii) every reimbursement obligation of the Corporation
with respect to letters of credit, bankers' acceptances or similar facilities
issued for the account of the Corporation; (iv) every obligation of the
Corporation issued or assumed as the deferred purchase price of property or
services (but excluding trade accounts payable or accrued liabilities arising in
the ordinary course of business); (v) every capital lease obligation of the
Corporation; (vi) all indebtedness of the Corporation, whether incurred on or
prior to the date of this Indenture or hereafter incurred, for claims in respect
of derivative products, including interest rate, foreign exchange rate and
commodity forward contracts, options and swaps and similar arrangements;



                                       5
<PAGE>   13

and (vii) every obligation of the type referred to in clauses (i) through (vi)
of another Person and all dividends of another Person the payment of which, in
either case, the Corporation has guaranteed or is responsible or liable for
directly or indirectly, as obligor or otherwise.

         "Indebtedness Ranking on a Parity with the Securities" shall mean (i)
Indebtedness, whether outstanding on the date of execution of this Indenture or
hereafter created, assumed or incurred, to the extent such Indebtedness by its
terms ranks pari passu with and not prior or senior to the Securities in the
right of payment upon the happening of the dissolution, winding-up, liquidation
or reorganization of the Corporation and (ii) all other debt securities, and
guarantees in respect of those debt securities, issued to any trust other than
the Trust, or a trustee of such trust, partnership or other entity affiliated
with the Corporation, that is a financing vehicle of the Corporation (a
"financing entity") in connection with the issuance by such financing entity of
equity securities or other securities guaranteed by the Corporation pursuant to
an instrument that ranks pari passu with or junior in right of payment to the
Capital Securities Guarantee. The securing of any Indebtedness otherwise
constituting Indebtedness Ranking on a Parity with the Securities shall not be
deemed to prevent such Indebtedness from constituting Indebtedness Ranking on a
Parity with the Securities with respect to any assets of the Corporation not
securing such Indebtedness.

         "Indebtedness Ranking Junior to the Securities" shall mean any
Indebtedness, whether outstanding on the date of execution of this Indenture or
hereafter created, assumed or incurred, to the extent such Indebtedness by its
terms ranks junior to and not pari passu with or prior to the Securities (and
any other Indebtedness Ranking on a Parity with the Securities) in right of
payment upon the happening of the dissolution or winding-up or liquidation or
reorganization of the Corporation. The securing of any Indebtedness otherwise
constituting Indebtedness Ranking Junior to the Securities shall not be deemed
to prevent such Indebtedness from constituting Indebtedness Ranking Junior to
the Securities with respect to any assets of the Corporation not securing such
Indebtedness.

         "Indenture" shall mean this instrument as originally executed or, if
amended as herein provided, as so amended.

         "Initial Optional Redemption Date" shall mean May 1, 2010.

         "Initial Securities" shall mean the Corporation's 9.34% Junior
Subordinated Deferrable Interest Debentures due May 1, 2030, Series A, as
authenticated and issued under this Indenture.

         "Interest Payment Date" shall have the meaning set forth in Section
2.06(a).

         "Investment Company" shall mean an investment company as defined in the
Investment Company Act.

         "Investment Company Act" shall mean the Investment Company Act of 1940,
as amended from time to time, or any successor legislation.



                                       6
<PAGE>   14

         "Investment Company Event" shall mean the receipt by the Corporation
and the Trust of an opinion of independent securities counsel experienced in
such matters to the effect that as a result of (a) any amendment to, or change
(including any announced prospective change) in, the laws or any regulations
thereunder of the United States or any rules, guidelines or policies of any
applicable regulatory authority for the Corporation or (b) any official
administrative pronouncement or judicial decision interpreting or applying such
laws or regulations, which amendment or change is effective or which
pronouncement or decision is announced on or after the date of original issuance
of the Initial Securities, the Trust is, or within 90 days of the date of such
opinion will be, considered an investment company that is required to be
registered under the Investment Company Act.

         "Like Amount" shall mean (i) with respect to a redemption of the Trust
Securities, Trust Securities having a liquidation amount equal to the principal
amount of Securities to be paid in accordance with their terms and (ii) with
respect to a distribution of Securities upon the liquidation of the Trust,
Securities having a principal amount equal to the liquidation amount of the
Trust Securities of the holder to whom Securities are distributed.

         "Liquidated Damages" shall have the meaning set forth in the
Registration Rights Agreement and the Liquidated Damages Agreement.

         "Liquidated Damages Agreement" shall mean the Liquidated Damages
Agreement, dated as of March 31, 2000 by and among the Corporation, the Trust
and the Initial Purchaser named therein, as such agreement may be amended,
modified or supplemented from time to time.

         "Maturity Date" shall mean May 1, 2030.

         "Non Book-Entry Capital Securities" shall have the meaning set forth in
Section 2.05(a)(ii).

         "Officers" shall mean any of the Chairman, the Chief Executive Officer,
the President, an Executive or Senior Vice President, a Vice President, the
Chief Financial Officer, the Secretary or an Assistant Secretary of the
Corporation.

         "Officers' Certificate" shall mean a certificate signed by two Officers
and delivered to the Debenture Trustee.

         "Opinion of Counsel" shall mean a written opinion of counsel, who may
be an employee of the Corporation, and who shall be reasonably acceptable to the
Debenture Trustee.

         "Optional Prepayment Price" shall have the meaning set forth in Section
14.02(a).

         "Other Debentures" shall mean all junior subordinated debentures other
than the Securities issued by the Corporation from time to time and sold to
trusts other than the Trust to be established by the Corporation (if any), in
each case similar to the Trust.



                                       7
<PAGE>   15

         "Other Guarantees" shall mean all guarantees other than the Capital
Securities Guarantee and the Common Securities Guarantee issued by the
Corporation with respect to preferred beneficial interests (if any) issued to
trusts other than the Trust to be established by the Corporation (if any), in
each case similar to the Trust.

         The term "outstanding" when used with reference to the Securities,
shall mean, subject to the provisions of Section 7.04, as of any particular
time, all Securities authenticated and delivered by the Debenture Trustee or the
Authenticating Agent under this Indenture, except

                  (a)      Securities theretofore canceled by the Debenture
                           Trustee or the Authenticating Agent or delivered to
                           the Debenture Trustee for cancellation;

                  (b)      Securities, or portions thereof, for the payment or
                           prepayment of which moneys in the necessary amount
                           shall have been deposited in trust with the Debenture
                           Trustee or with any paying agent (other than the
                           Corporation) or shall have been set aside and
                           segregated in trust by the Corporation (if the
                           Corporation shall act as its own paying agent);
                           provided that, if such Securities, or portions
                           thereof, are to be prepaid prior to maturity thereof,
                           notice of such prepayment shall have been given as
                           set forth in Article XIV or provision satisfactory to
                           the Debenture Trustee shall have been made for giving
                           such notice; and

                  (c)      Securities in lieu of or in substitution for which
                           other Securities shall have been authenticated and
                           delivered pursuant to the terms of Section 2.08
                           unless proof satisfactory to the Corporation and the
                           Debenture Trustee is presented that any such
                           Securities are held by bona fide holders in due
                           course.

         "Person" shall mean any individual, corporation, estate, partnership,
joint venture, national banking association, association, joint-stock company,
limited liability company, trust, unincorporated organization or government or
any agency or political subdivision thereof.

         "Predecessor Security" of any particular Security shall mean every
previous Security evidencing all or a portion of the same debt as that evidenced
by such particular Security; and, for the purposes of this definition, any
Security authenticated and delivered under Section 2.08 in lieu of a lost,
destroyed or stolen Security shall be deemed to evidence the same debt as the
lost, destroyed or stolen Security.

         "Prepayment Price" shall mean the Special Event Prepayment Price or
Optional Prepayment Price, as the context requires.

         "Principal Office of the Debenture Trustee," or other similar term,
shall mean the office of the Debenture Trustee, at which at any particular time
its corporate trust business shall be administered.



                                       8
<PAGE>   16

         "Purchase Agreement" shall mean the Purchase Agreement, dated March 28,
2000, by and among the Corporation, the Trust and the Initial Purchaser named
therein.

         "Quotation Agent" shall mean the Reference Treasury Dealer appointed by
the Corporation.

         "Reference Treasury Dealer" shall mean a nationally recognized U.S.
Government securities dealer in New York, New York selected by the Corporation.

         "Reference Treasury Dealer Quotations" shall mean, with respect to each
Reference Treasury Dealer and any prepayment date pursuant to Section 14.01, the
average, as determined by the Quotation Agent, of the bid and asked prices for
the Comparable Treasury Issue (expressed in each case as a percentage of its
principal amount) quoted in writing to the Quotation Agent by such Reference
Treasury Dealer at 5:00 p.m., New York City time, on the third Business Day
preceding such prepayment date.

         "Registration Rights Agreement" shall mean the Registration Rights
Agreement, dated as of March 28, 2000, by and among the Corporation, the Trust
and the Initial Purchaser named therein, as such agreement may be amended,
modified or supplemented from time to time.

         "Regulatory Capital Event" shall mean the receipt by the Corporation
and the Trust of an opinion of independent bank regulatory counsel experienced
in such matters to the effect that as a result of (a) any amendment to, or
change (including any announced prospective change) in, the laws (or any
regulations thereunder) of the United States or any rules, guidelines or
policies of an applicable regulatory authority for the Corporation or (b) any
official administrative pronouncement or judicial decision interpreting or
applying such laws or regulations, which amendment or change is effective or
which pronouncement or decision is announced on or after the date of original
issuance of the Initial Securities, the Capital Securities do not constitute, or
within 90 days of the date of such opinion will not constitute, Tier 1 Capital
(or its then equivalent if the Corporation were subject to such capital
requirement) applied as if the Corporation (or its successors) were a bank
holding company for purposes of capital adequacy guidelines of the Federal
Reserve Board (or any successor regulatory authority with jurisdiction over bank
holding companies), or any capital adequacy guidelines as then in effect and
applicable to the Corporation; PROVIDED, HOWEVER, that the distribution of the
Securities in connection with the liquidation of the Trust by the Corporation
shall not in and of itself constitute a Regulatory Capital Event.

         "Remaining Life" shall mean the term of the Securities from any
prepayment date pursuant to Section 14.01 to the Maturity Date.

         "Responsible Officer" shall mean any officer of the Debenture Trustee's
Corporate Trust Administration Department with direct responsibility for the
administration of the Indenture and also means, with respect to a particular
corporate trust matter, any other officer of the Debenture Trustee to whom such
matter is referred because of such officer's knowledge of and familiarity with
the particular subject.



                                       9
<PAGE>   17

         "Restricted Security" shall mean Securities that bear or are required
to bear the legends relating to transfer restrictions under the Securities Act
set forth in Exhibit A hereto.

         "Rule 144A" shall mean Rule 144A under the Securities Act, as such Rule
may be amended from time to time, or any similar rule or regulation hereafter
adopted by the Commission.

         "Securities" shall mean, collectively, the Initial Securities and the
Exchange Securities.

         "Securityholder," "holder of Securities," or other similar terms, shall
mean any Person in whose name at the time a particular Security is registered in
the Security Register kept by the Corporation or the Debenture Trustee for that
purpose in accordance with the terms of this Indenture.

         "Security Register" shall mean (i) prior to a Dissolution Event, the
list of holders provided to the Debenture Trustee pursuant to Section 4.01, and
(ii) following a Dissolution Event, any security register maintained by a
security registrar for the Securities appointed by the Corporation following the
execution of a supplemental indenture providing for transfer procedures as
provided for in Section 2.07(a).

         "Senior Indebtedness" shall mean the principal of (and premium, if any)
and interest, if any (including interest accruing on or after the filing of any
petition in bankruptcy or for reorganization relating to the Corporation whether
or not such claim for post petition interest is allowed in such proceedings), on
all Indebtedness, whether outstanding on the date of execution of this
Indenture, or hereafter created, assumed or incurred, except Indebtedness
Ranking on a Parity with the Securities or Indebtedness Ranking Junior to the
Securities, and any deferrals, renewals or extensions of such Senior
Indebtedness.

         "Special Event" shall mean an Investment Company Event, a Regulatory
Capital Event or a Tax Event, as the context requires.

         "Special Event Prepayment Price" shall mean, with respect to any
prepayment of the Securities following a Special Event, an amount in cash equal
to the greater of (i) 100% of the principal amount of the Securities to be
prepaid or (ii) the sum, as determined by a Quotation Agent, of the present
values of the remaining scheduled payments of principal and interest on such
Securities, discounted to the prepayment date on a semi-annual basis (assuming a
360-day year consisting of twelve 30-day months) at the Adjusted Treasury Rate,
plus, in the case of each of (i) and (ii), any accrued and unpaid interest
thereon (including Compounded Interest and Additional Sums, if any) to the date
of such prepayment.

         "Subsidiary" shall mean with respect to any Person, (i) any corporation
at least a majority of the outstanding voting stock of which is owned, directly
or indirectly, by such Person or by one or more of its Subsidiaries, or by such
Person and one or more of its Subsidiaries, (ii) any general partnership, joint
venture, limited liability company or similar entity, at least a majority of
whose outstanding partnership, membership or similar interests shall at the time
be owned by such Person or by one or more of its Subsidiaries, or by such Person
and one or more of its



                                       10
<PAGE>   18

Subsidiaries and (iii) any limited partnership of which such Person or any of
its Subsidiaries is a general partner. For the purposes of this definition,
"voting stock" means shares, interests, participations or other equivalents in
the equity interest (however designated) in such Person having ordinary voting
power for the election of a majority of the directors (or the equivalent) of
such Person, other than shares, interests, participations or other equivalents
having such power only by reason of the occurrence of a contingency.

         "Tax Event" shall mean the receipt by the Trust and the Corporation of
an opinion of independent tax counsel experienced in such matters to the effect
that, as a result of any amendment to, or change (including any announced
prospective change) in, the laws or any regulations thereunder of the United
States or any political subdivision or taxing authority thereof or therein, or
as a result of any official administrative pronouncement or judicial decision
interpreting or applying such laws or regulations, which amendment or change is
effective or which pronouncement or decision is announced on or after the date
of original issuance of the Initial Securities, there is more than an
insubstantial risk that (i) the Trust is, or will be within 90 days of the date
of such opinion, subject to United States federal income tax with respect to
income received or accrued on the Securities, (ii) the interest payable by the
Corporation on the Securities is not, or within 90 days of the date of such
opinion will not be, deductible by the Corporation, in whole or in part, for
United States federal income tax purposes or (iii) the Trust is, or will be
within 90 days of the date of such opinion, subject to more than a de minimis
amount of other taxes, duties or other governmental charges.

         "Trust" shall mean Sky Financial Capital Trust I, a Delaware business
trust created for the purpose of issuing its undivided beneficial interests in
connection with the issuance of Securities under this Indenture.

         "Trust Securities" shall mean, collectively, the Capital Securities and
the Common Securities.

         "U.S. Government Obligations" shall mean securities that are (i) direct
obligations of the United States of America for the payment of which its full
faith and credit is pledged or (ii) obligations of a Person controlled or
supervised by and acting as an agency or instrumentality of the United States of
America the payment of which is unconditionally guaranteed as a full faith and
credit obligation by the United States of America, which, in either case under
clauses (i) or (ii), are not callable or prepayable at the option of the issuer
thereof, and shall also include a depository receipt issued by a bank or trust
company as custodian with respect to any such U.S. Government Obligation or a
specific payment of interest on or principal of any such U.S. Government
Obligation held by such custodian for the account of the holder of a depository
receipt, provided that (except as required by law) such custodian is not
authorized to make any deduction with respect to the amount payable to the
holder of such depository receipt from any amount received by the custodian in
respect of the U.S. Government Obligation or the specific payment of interest on
or principal of the U.S. Government Obligation evidenced by such depository
receipt.

         SECTION 1.01  BUSINESS DAY CERTIFICATE.



                                       11
<PAGE>   19

         On the date of execution and delivery of this Indenture (with respect
to the remainder of calendar year 2000) and within 15 days prior to the end of
each calendar year while this Indenture remains in effect (with respect to
succeeding calendar years), the Corporation shall deliver to the Debenture
Trustee an Officers' Certificate specifying the days on which banking
institutions or trust companies in Wilmington, Delaware, Bowling Green, Ohio or
New York, New York are then authorized or obligated by law or executive order to
remain closed.


                                   ARTICLE II
                                   SECURITIES

         SECTION 2.01 FORMS GENERALLY.

         The Securities and the Debenture Trustee's certificate of
authentication shall be substantially in the form of Exhibit A hereto, the terms
of which are incorporated in and made a part of this Indenture. The Securities
may have notations, legends or endorsements required by law, stock exchange
rule, agreements to which the Corporation is subject or usage. Each Security
shall be dated the date of its authentication.

         SECTION 2.02 EXECUTION AND AUTHENTICATION.

         An Officer shall sign the Securities for the Corporation by manual or
facsimile signature. If an Officer whose signature is on a Security no longer
holds that office at the time the Security is authenticated, the Security shall
nevertheless be valid.

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

         The Debenture Trustee shall, upon a Corporation Order, authenticate for
original issue up to, and the aggregate principal amount of Securities
outstanding at any time may not exceed, $60,000,000 aggregate principal amount
of the Securities, except as provided in Sections 2.07, 2.08, 2.09 and 14.05.
The series of Securities to be initially issued hereunder shall be the Initial
Securities.

         SECTION 2.03 FORM AND PAYMENT.

         Except as provided in Section 2.05, the Securities shall be issued in
fully registered certificated form without interest coupons. Principal of and
premium, if any, and interest on the Securities issued in certificated form will
be payable, the transfer of such Securities will be registrable and such
Securities will be exchangeable for Securities bearing identical terms and
provisions, at the office or agency of the Corporation maintained for such
purpose under Section 3.02; PROVIDED, HOWEVER, that payments of interest may be
made at the option of the Corporation (i) by check mailed to the holder at such
address as shall appear in the Security Register, or (ii) by transfer to an
account maintained by the Person entitled thereto, provided that proper transfer
instructions have been received in writing by the relevant record date.
Notwithstanding the



                                       12
<PAGE>   20

foregoing, so long as the holder of any Securities is the Property Trustee, the
payment of the principal of and premium, if any, and interest (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
on such Securities held by the Property Trustee will be made at such place and
to such account as may be designated by the Property Trustee.

         SECTION 2.04  LEGENDS

         (a) Except as permitted by subsection (b) of this Section 2.04, or as
otherwise determined by the Corporation in accordance with applicable law, each
Security shall bear the applicable legends relating to restrictions on transfer
pursuant to the Securities Act and any other applicable securities laws in
substantially the form set forth on Exhibit A hereto.

         (b) In the event of an Exchange Offer, the Corporation shall issue and
the Debenture Trustee, upon Corporation Order, shall authenticate Exchange
Securities in exchange for Initial Securities accepted for exchange in the
Exchange Offer, which Exchange Securities shall not bear the legends required by
subsection (a) above, in each case unless the holder of such Initial Securities
is either (A) a broker-dealer who purchased such Initial Securities directly
from the Corporation for resale pursuant to Rule 144A or any other available
exemption under the Securities Act, (B) a Person participating in the
distribution of the Initial Securities or (C) a Person who is an Affiliate of
the Corporation or the Trust.

         SECTION 2.05 GLOBAL SECURITY.

         (a) In connection with a Dissolution Event,

                  (i) if any Capital Securities are held in book-entry form
("Book-Entry Capital Securities"), a Like Amount of Definitive Securities shall
be presented to the Debenture Trustee (if an arrangement with the Depositary has
been maintained) by the Property Trustee in exchange for one or more Global
Securities (as may be required pursuant to Section 2.07), to be registered in
the name of the Depositary, or its nominee, and delivered by the Debenture
Trustee to the Depositary for crediting to the accounts of its participants
pursuant to the instructions of the Administrative Trustees; the Corporation
upon any such presentation shall execute one or more Global Securities in such
aggregate principal amount and deliver the same to the Debenture Trustee for
authentication and delivery in accordance with this Indenture; and payments on
the Securities issued as a Global Security will be made to the Depositary; and

                  (ii) if any Capital Securities are held in certificated form,
the related Definitive Securities may be presented to the Debenture Trustee by
the Property Trustee and any Capital Security certificates which represent
Capital Securities other than Book-Entry Capital Securities ("Non Book-Entry
Capital Securities") will be deemed to represent beneficial interests in
Securities presented to the Debenture Trustee by the Property Trustee having an
aggregate principal amount equal to the aggregate liquidation amount of the Non
Book-Entry Capital Securities until such Capital Security certificates are
presented to the security registrar for the Securities for transfer or
reissuance, at which time such Capital Security certificates will be canceled,
and a Security in a Like Amount, registered in the name of the holder of the
Capital Security certificate or the transferee of the holder of such Capital
Security certificate, as the case



                                       13
<PAGE>   21

may be, will be executed by the Corporation and delivered to the Debenture
Trustee for authentication and delivery in accordance with this Indenture; and
upon the issuance of such Securities, Securities with an equivalent aggregate
principal amount that were presented by the Property Trustee to the Debenture
Trustee will be canceled.

         (b) The Global Securities shall represent the aggregate amount of
outstanding Securities from time to time endorsed thereon; PROVIDED, HOWEVER,
that the aggregate principal amount of outstanding Securities represented
thereby may from time to time be reduced or increased, as appropriate, to
reflect exchanges and prepayments. Any endorsement of a Global Security to
reflect the amount of any increase or decrease in the aggregate principal amount
of outstanding Securities represented thereby shall be made by the Debenture
Trustee, in accordance with instructions given by the Corporation as required by
this Section 2.05.

         (c) The Global Securities may be transferred, in whole but not in part,
only to the Depositary, to another nominee of the Depositary, or to a successor
Depositary selected or approved by the Corporation or to a nominee of such
successor Depositary.

         (d) If at any time the Depositary notifies the Corporation that it is
unwilling or unable to continue as Depositary or the Depositary has ceased to be
a clearing agency registered under the Exchange Act, and, in each case, a
successor Depositary is not appointed by the Corporation within 90 days after
the Corporation receives such notice or becomes aware of such condition, as the
case may be, the Corporation will execute, and the Debenture Trustee, upon
receipt of a Corporation Order, will authenticate and make available for
delivery the Definitive Securities, in authorized denominations, and in an
aggregate principal amount equal to the principal amount of the Global Security,
in exchange for such Global Security. If there is a Default or an Event of
Default, the Depositary shall have the right to exchange the Global Securities
for Definitive Securities. In addition, the Corporation may at any time
determine that the Securities shall no longer be represented by a Global
Security. In the event of such an Event of Default or such a determination, the
Corporation shall execute, and subject to Section 2.07, the Debenture Trustee,
upon receipt of an Officers' Certificate evidencing such determination by the
Corporation and a Corporation Order, will authenticate and make available for
delivery the Definitive Securities, in authorized denominations, and in an
aggregate principal amount equal to the principal amount of the Global Security,
in exchange for such Global Security. Upon the exchange of the Global Security
for such Definitive Securities, in authorized denominations, the Global Security
shall be canceled by the Debenture Trustee. Such Definitive Securities issued in
exchange for the Global Security shall be registered in such names and in such
authorized denominations as the Depositary, pursuant to instructions from its
direct or indirect participants or otherwise, shall instruct the Debenture
Trustee. The Debenture Trustee shall deliver such Definitive Securities to the
Depositary for delivery to the Persons in whose names such Definitive Securities
are so registered.

         SECTION 2.06  INTEREST.

         (a) Each Security will bear interest, at the rate of 9.34% per annum
(the "Coupon Rate"), from the most recent date to which interest has been paid
or duly provided for or, if no interest has been paid or duly provided for, from
March 31, 2000 until the principal thereof



                                       14
<PAGE>   22

becomes due and payable, and at the Coupon Rate on any overdue principal (and
premium, if any) and (to the extent that payment of such interest is enforceable
under applicable law) on any overdue installment of interest, compounded
semi-annually, payable (subject to the provisions of Article XVI) semi-annually
in arrears on May 1st and November 1st of each year, commencing November 1, 2000
(each, an "Interest Payment Date"), to the Person in whose name such Security or
any predecessor Security is registered at the close of business on the regular
record date for such interest installment, which shall be the 15th day of the
month immediately preceding the month in which the relevant Interest Payment
Date falls.

         (b) The amount of interest payable on the Securities shall be computed
on the basis of a 360-day year of twelve 30-day months.

         (c) During such time as the Property Trustee is the holder of any
Securities, the Corporation shall pay any additional amounts on the Securities
as may be necessary in order that the amount of Distributions then due and
payable by the Trust on the outstanding Trust Securities shall not be reduced as
a result of any additional taxes, duties and other governmental charges to which
the Trust has become subject as a result of a Tax Event ("Additional Sums").

         SECTION 2.07 TRANSFER AND EXCHANGE.

         (a) TRANSFER RESTRICTIONS.

                  (i) The Initial Securities, and those Exchange Securities with
respect to which any Person described in Section 2.04(b)(A), (B) or (C) is the
beneficial owner, may not be transferred except in compliance with the legend
contained in Exhibit A unless otherwise determined by the Corporation in
accordance with applicable law. Upon any distribution of the Securities
following a Dissolution Event, the Corporation and the Debenture Trustee shall
enter into a supplemental indenture pursuant to Section 9.01 to provide for the
transfer restrictions and procedures with respect to the Securities
substantially similar to those contained in the Declaration to the extent
applicable in the circumstances existing at such time.

                  (ii) The Securities will be issued and may be transferred only
in blocks having an aggregate principal amount of not less than $100,000 and in
multiples of $1,000 in excess thereof. Any attempted transfer of the Securities
in a block having an aggregate principal amount of less than $100,000 shall be
deemed to be voided and of no legal effect whatsoever. Any such purported
transferee shall be deemed not to be a holder of such Securities for any
purpose, including, but not limited to the receipt of payments on such
Securities, and such purported transferee shall be deemed to have no interest
whatsoever in such Securities.

         (b) GENERAL PROVISIONS RELATING TO TRANSFERS AND EXCHANGES. To permit
registrations of transfers and exchanges, the Corporation shall execute and the
Debenture Trustee shall authenticate Definitive Securities and Global Securities
at the request of the security registrar for the Securities. All Definitive
Securities and Global Securities issued upon any registration of transfer or
exchange of Definitive Securities or Global Securities shall be the valid
obligations of the Corporation, evidencing the same debt, and entitled to the
same benefits under this Indenture, as

                                       15
<PAGE>   23

the Definitive Securities or Global Securities surrendered upon such
registration of transfer or exchange.

         No service charge shall be made to a holder for any registration of
transfer or exchange, but the Corporation may require payment of a sum
sufficient to cover any transfer tax or similar governmental charge payable in
connection therewith.

         The Corporation shall not be required to: (i) issue, register the
transfer of or exchange Securities during a period beginning at the opening of
business 15 days before the day of mailing of a notice of prepayment or any
notice of selection of Securities for prepayment under Article XIV hereof and
ending at the close of business on the day of such mailing; or (ii) register the
transfer of or exchange any Security so selected for prepayment in whole or in
part, except the nonprepaid portion of any Security being prepaid in part.

         Prior to due presentment for the registration of a transfer of any
Security, the Debenture Trustee, the Corporation and any agent of the Debenture
Trustee or the Corporation may deem and treat the Person in whose name any
Security is registered as the absolute owner of such Security for the purpose of
receiving payment of principal of and premium, if any, and interest on such
Securities, and none of the Debenture Trustee, the Corporation or any agents of
the Debenture Trustee or the Corporation shall be affected by notice to the
contrary.

         (c) EXCHANGE OF INITIAL SECURITIES FOR EXCHANGE SECURITIES. The Initial
Securities may be exchanged for Exchange Securities pursuant to the terms of the
Exchange Offer. The Debenture Trustee shall make the exchange as follows:

         The Corporation shall present the Debenture Trustee with an Officers'
Certificate certifying the following:

         (A)      upon issuance of the Exchange Securities, the transactions
                  contemplated by the Exchange Offer have been consummated; and

         (B)      the principal amount of Initial Securities properly tendered
                  in the Exchange Offer that are represented by a Global
                  Security, the principal amount of Initial Securities properly
                  tendered in the Exchange Offer that are represented by
                  Definitive Securities, the name of each holder of such
                  Definitive Securities, the principal amount properly tendered
                  in the Exchange Offer by each such holder and the name and
                  address to which Definitive Securities for Exchange Securities
                  shall be registered and sent for each such holder.

         The Debenture Trustee, upon receipt of (i) such Officers' Certificate,
(ii) an Opinion of Counsel (x) to the effect that the Exchange Securities have
been registered under Section 5 of the Securities Act and the Indenture has been
qualified under the Trust Indenture Act and (y) with respect to the matters set
forth in Section 3(q) of the Registration Rights Agreement and (iii) a
Corporation Order, shall authenticate (A) a Global Security representing
Exchange Securities in aggregate principal amount equal to the aggregate
principal amount of Initial Securities represented by a Global Security
indicated in such Officers' Certificate as having been properly



                                       16
<PAGE>   24

tendered and (B) Definitive Securities representing Exchange Securities
registered in the names of, and in the principal amounts indicated in, such
Officers' Certificate.

         If the principal amount of the Global Security for the Exchange
Securities is less than the principal amount of the Global Security for the
Initial Securities, the Debenture Trustee shall make an endorsement on such
Global Security for Initial Securities indicating a reduction in the principal
amount represented thereby.

         The Debenture Trustee shall deliver such Definitive Securities
representing Exchange Securities to the holders thereof as indicated in such
Officers' Certificate.

         SECTION 2.08 REPLACEMENT SECURITIES.

         If any mutilated Security is surrendered to the Debenture Trustee, or
the Corporation and the Debenture Trustee receive evidence to their satisfaction
of the destruction, loss or theft of any Security, the Corporation shall issue
and the Debenture Trustee shall authenticate a replacement Security if the
Debenture Trustee's requirements for replacements of Securities are met. An
indemnity bond must be supplied by the holder that is sufficient in the judgment
of the Debenture Trustee and the Corporation to protect the Corporation, the
Debenture Trustee, any agent thereof or any Authenticating Agent from any loss
that any of them may suffer if a Security is replaced. The Corporation or the
Debenture Trustee may charge for its expenses in replacing a Security.

         Every replacement Security is an obligation of the Corporation and
shall be entitled to all of the benefits of this Indenture equally and
proportionately with all other Securities duly issued hereunder.

         SECTION 2.09 TEMPORARY SECURITIES.

         Pending the preparation of Definitive Securities, the Corporation may
execute, and upon Corporation Order the Debenture Trustee shall authenticate and
make available for delivery, temporary Securities that are printed,
lithographed, typewritten, mimeographed or otherwise reproduced, in any
authorized denomination, substantially of the tenor of the Definitive Securities
in lieu of which they are issued and with such appropriate insertions,
omissions, substitutions and other variations as the Officers executing such
Securities may determine, as conclusively evidenced by their execution of such
Securities.

         If temporary Securities are issued, the Corporation shall cause
Definitive Securities to be prepared without unreasonable delay. The Definitive
Securities shall be printed, lithographed or engraved, or provided by any
combination thereof, or in any other manner permitted by the rules and
regulations of any applicable securities exchange, all as determined by the
Officers executing such Definitive Securities. After the preparation of
Definitive Securities, the temporary Securities shall be exchangeable for
Definitive Securities upon surrender of the temporary Securities at the office
or agency maintained by the Corporation for such purpose pursuant to Section
3.02 hereof, without charge to the holder thereof. Upon surrender for
cancellation of any one or more temporary Securities, the Corporation shall
execute, and the



                                       17
<PAGE>   25

Debenture Trustee shall authenticate and make available for delivery, in
exchange therefor the same aggregate principal amount of Definitive Securities
of authorized denominations. Until so exchanged, the temporary Securities shall
in all respects be entitled to the same benefits under this Indenture as
Definitive Securities.

         SECTION 2.10 CANCELLATION.

         The Corporation at any time may deliver Securities to the Debenture
Trustee for cancellation. The Debenture Trustee and no one else shall cancel all
Securities surrendered for registration of transfer, exchange, payment,
replacement or cancellation and shall return such canceled Securities to the
Corporation. The Corporation may not issue new Securities to replace Securities
that have been prepaid or paid or that have been delivered to the Debenture
Trustee for cancellation.

         SECTION 2.11 DEFAULTED INTEREST.

         Any interest on any Security that is payable, but is not punctually
paid or duly provided for, on any Interest Payment Date (herein called
"Defaulted Interest") shall forthwith cease to be payable to the holder on the
relevant regular record date by virtue of having been such holder; and such
Defaulted Interest shall be paid by the Corporation, at its election, as
provided in clause (a) or clause (b) below:

                  (a) The Corporation may make payment of any Defaulted Interest
         on Securities to the Persons in whose names such Securities (or their
         respective Predecessor Securities) 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 Corporation
         shall notify the Debenture Trustee in writing of the amount of
         Defaulted Interest proposed to be paid on each such Security and the
         date of the proposed payment, and at the same time the Corporation
         shall deposit with the Debenture Trustee an amount of money equal to
         the aggregate amount proposed to be paid in respect of such Defaulted
         Interest or shall make arrangements satisfactory to the Debenture
         Trustee for such deposit 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 Debenture Trustee shall fix a special record date for
         the payment of such Defaulted Interest which shall not be more than 15
         nor less than 10 days prior to the date of the proposed payment and not
         less than 10 days after the receipt by the Debenture Trustee of the
         notice of the proposed payment. The Debenture Trustee shall promptly
         notify the Corporation of such special record date and, in the name and
         at the expense of the Corporation, 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 Securityholder at
         his or her address as it appears in the Security Register, not less
         than 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 mailed as aforesaid, such Defaulted Interest shall be paid
         to the Persons in whose names such Securities (or their respective
         Predecessor Securities) are registered on such special record date and
         shall be no longer payable pursuant to the following clause (b).



                                       18
<PAGE>   26

                  (b) The Corporation may make payment of any Defaulted Interest
          on any Securities in any other lawful manner not inconsistent with the
          requirements of any securities exchange on which such Securities may
          be listed, and upon such notice as may be required by such exchange,
          if, after notice given by the Corporation to the Debenture Trustee of
          the proposed payment pursuant to this clause, such manner of payment
          shall be deemed practicable by the Debenture Trustee.

         SECTION 2.12 CUSIP NUMBERS.

         The Corporation in issuing the Securities may use "CUSIP" numbers (if
then generally in use), and, if so, the Debenture Trustee shall use "CUSIP"
numbers in notices of prepayment as a convenience to Securityholders; PROVIDED,
HOWEVER, that any such notice may state that no representation is made as to the
correctness of such numbers either as printed on the Securities or as contained
in any notice of a prepayment and that reliance may be placed only on the other
identification numbers printed on the Securities, and any such prepayment shall
not be affected by any defect in or omission of such numbers. The Corporation
will promptly notify the Debenture Trustee of any change in the CUSIP numbers.


                                   ARTICLE III
                     PARTICULAR COVENANTS OF THE CORPORATION

         SECTION 3.01 PAYMENT OF PRINCIPAL AND INTEREST.

         The Corporation covenants and agrees for the benefit of the holders of
the Securities that it will duly and punctually pay or cause to be paid the
principal of and premium, if any, and interest on the Securities at the place,
at the respective times and in the manner provided herein. The Corporation
further covenants to pay any and all amounts due in respect of the Securities,
including, without limitation, Additional Sums, as may be required pursuant to
Section 2.06(c), Liquidated Damages, if any, on the dates and in the manner
required under the Registration Rights Agreement or the Liquidated Damages
Agreement and Compounded Interest, as may be required pursuant to Section 16.01.

         SECTION 3.02 OFFICES FOR NOTICES AND PAYMENTS, ETC.

         So long as any of the Securities remain outstanding, the Corporation
will maintain in Wilmington, Delaware an office or agency where the Securities
may be presented for payment, an office or agency where the Securities may be
presented for registration of transfer and for exchange as in this Indenture
provided and an office or agency where notices and demands to or upon the
Corporation in respect of the Securities or this Indenture may be served. The
Corporation will give to the Debenture Trustee written notice of the location of
any such office or agency and of any change of location thereof. Until otherwise
designated from time to time by the Corporation in a notice to the Debenture
Trustee, any such office or agency for all of the above purposes shall be the
Principal Office of the Debenture Trustee. In case the Corporation shall fail to
maintain any such office or agency in Wilmington, Delaware or shall fail to give


                                       19
<PAGE>   27

such notice of the location or of any change in the location thereof,
presentations and demands may be made and notices may be served at the Principal
Office of the Debenture Trustee.

         In addition to any such office or agency, the Corporation may from time
to time designate one or more offices or agencies outside Wilmington, Delaware
where the Securities may be presented for payment, for registration of transfer
and for exchange and where notices and demands to or upon the Corporation in
respect of the Securities or this Indenture may be served in the manner provided
in this Indenture, and the Corporation may from time to time rescind such
designation, as the Corporation may deem desirable or expedient; PROVIDED,
however, that no such designation or rescission shall in any manner relieve the
Corporation of its obligation to maintain any such office or agency in
Wilmington, Delaware for the purposes above mentioned. The Corporation will give
to the Debenture Trustee prompt written notice of any such designation or
rescission thereof.

         SECTION 3.03 APPOINTMENTS TO FILL VACANCIES IN DEBENTURE TRUSTEE'S
OFFICE.

         The Corporation, whenever necessary to avoid or fill a vacancy in the
office of Debenture Trustee, will appoint, in the manner provided in Section
6.10, a Debenture Trustee, so that there shall at all times be a Debenture
Trustee hereunder.

         SECTION 3.04 PROVISION AS TO PAYING AGENT.

         (a) If the Corporation shall appoint a paying agent other than the
Debenture Trustee with respect to the Securities, it will cause such paying
agent to execute and deliver to the Debenture Trustee an instrument in which
such agent shall agree with the Debenture Trustee, subject to the provisions of
this Section 3.04,

                  (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 Securities (whether such sums
                           have been paid to it by the Corporation or by any
                           other obligor on the Securities) in trust for the
                           benefit of the holders of the Securities; and

                  (2)      that it will give the Debenture Trustee notice of any
                           failure by the Corporation (or by any other obligor
                           on the Securities) to make any payment of the
                           principal of or premium, if any, or interest
                           (including Additional Sums and Compounded Interest,
                           if any) and Liquidated Damages, if any, on the
                           Securities when the same shall be due and payable.

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



                                       20
<PAGE>   28

to make any payment of the principal of and, premium, if any, or interest on the
Securities when the same shall become due and payable.

         (c) Anything in this Section 3.04 to the contrary notwithstanding, the
Corporation may, at any time, for the purpose of obtaining a satisfaction and
discharge with respect to the Securities hereunder, or for any other reason, pay
or cause to be paid to the Debenture Trustee all sums payable with respect to
the Securities, such sums to be held by the Debenture Trustee upon the trusts
herein contained.

         (d) Anything in this Section 3.04 to the contrary notwithstanding, the
agreement to hold sums in trust as provided in this Section 3.04 is subject to
Sections 11.03 and 11.04.

         SECTION 3.05 CERTIFICATE TO DEBENTURE TRUSTEE.

         The Corporation will deliver to the Debenture Trustee on or before 120
days after the end of each fiscal year of the Corporation, commencing with the
first fiscal year ending after the date hereof, so long as Securities are
outstanding hereunder, an Officers' Certificate, one of the signers of which
shall be the principal executive, principal financial or principal accounting
officer of the Corporation, stating that in the course of the performance by the
signers of their duties as officers of the Corporation they would normally have
knowledge of any Default by the Corporation in the performance of any covenants
contained herein, stating whether or not they have knowledge of any such Default
and, if so, specifying each such Default of which the signers have knowledge,
the nature thereof and the action, if any, the Corporation intends to undertake
as a result of such Default.

         SECTION 3.06 COMPLIANCE WITH CONSOLIDATION PROVISIONS.

         The Corporation will not, while any of the Securities remain
outstanding, consolidate with, or merge into, or merge into itself, or sell or
convey all or substantially all of its property to any other Person unless the
provisions of Article X hereof are complied with.

         SECTION 3.07 LIMITATION ON DIVIDENDS.

         The Corporation will not (i) declare or pay any dividends or
distributions on, or redeem, purchase, acquire, or make a liquidation payment
with respect to, any of the Corporation's capital stock, (ii) make any payment
of principal of or premium, if any, or interest on or repay, repurchase or
redeem any debt securities of the Corporation (including Other Debentures) that
rank pari passu with or junior in right of payment to the Securities or (iii)
make any guarantee payments with respect to any guarantee (other than the
Capital Securities Guarantee) by the Corporation of the debt securities of any
Subsidiary of the Corporation (including Other Guarantees) if such guarantee
ranks pari passu with or junior in right of payment to the Securities (other
than (a) dividends or distributions in shares of, or options, warrants or rights
to subscribe for or purchase shares of, Common Stock, (b) any declaration of a
dividend in connection with the implementation of a stockholders' rights plan,
or the issuance of stock under any such plan in the future, or the redemption or
repurchase of any such rights pursuant thereto, (c) as a result of a
reclassification of the Corporation's capital stock or the exchange or


                                       21
<PAGE>   29

conversion of one class or series of the Corporation's capital stock for another
class or series of the Corporation's capital stock, (d) the purchase of
fractional interests in shares of the Corporation's capital stock pursuant to
the conversion or exchange provisions of such capital stock or the security
being converted or exchanged and (e) purchases of Common Stock related to the
issuance of Common Stock or rights under any of the Corporation's benefit or
compensation plans for its directors, officers or employees or any of the
Corporation's dividend reinvestment plans), if at such time (1) there shall have
occurred any event of which the Corporation has actual knowledge that (a) is a
Default or an Event of Default and (b) in respect of which the Corporation shall
not have taken reasonable steps to cure, (2) the Securities are held by the
Property Trustee and the Corporation shall be in default with respect to its
payment of any obligations under the Capital Securities Guarantee or (3) the
Corporation shall have given notice of its election to exercise its right to
commence an Extended Interest Payment Period and shall not have rescinded such
notice, and such Extended Interest Payment Period or any extension thereof shall
have commenced and be continuing.

         SECTION 3.08 COVENANTS AS TO SKY FINANCIAL CAPITAL TRUST I

         In the event Securities are issued to the Trust or a trustee of such
Trust in connection with the issuance of Trust Securities by the Trust, for so
long as such Trust Securities remain outstanding, the Corporation (i) will
maintain 100% direct or indirect ownership of the Common Securities of the
Trust; PROVIDED, HOWEVER, that any successor of the Corporation, permitted
pursuant to Article X, may succeed to the Corporation's ownership of such Common
Securities, (ii) will use commercially reasonable efforts to cause the Trust (a)
to remain a business trust, except in connection with a distribution of
Securities to the holders of Trust Securities in liquidation of the Trust, the
redemption of all of the Trust Securities of the Trust, or certain mergers,
consolidations or amalgamations, each as permitted by the Declaration, and (b)
to otherwise continue to be classified as a grantor trust and not an association
taxable as a corporation for United States federal income tax purposes, (iii)
will use commercially reasonable efforts to cause each holder of the Trust
Securities to be treated as owning an undivided beneficial interest in the
Securities and (iv) will not cause, as sponsor of the Trust, or permit, as
holder of the Common Securities, the dissolution, winding-up or liquidation of
the Trust, except as provided in the Declaration.

         SECTION 3.09 PAYMENT OF EXPENSES.

         In connection with the offering, sale and issuance of the Securities to
the Trust and in connection with the sale of the Trust Securities by the Trust,
the Corporation, in its capacity as borrower with respect to the Securities,
shall:

         (a)      pay all costs and expenses relating to the offering, sale and
                  issuance of the Securities, including fees and expenses in
                  connection with any Exchange Offer, filing of a shelf
                  registration statement or other action to be taken pursuant to
                  the Registration Rights Agreement and Liquidated Damages
                  Agreement and compensation of the Debenture Trustee in
                  accordance with the provisions of Section 6.06;



                                       22
<PAGE>   30

         (b)      pay all costs and expenses of the Trust, including, but not
                  limited to, costs and expenses relating to the organization of
                  the Trust, the offering, sale and issuance of the Trust
                  Securities (including commissions payable to the Initial
                  Purchaser pursuant to the Purchase Agreement in connection
                  therewith), the fees and expenses of the Property Trustee and
                  the Delaware Trustee, the costs and expenses relating to the
                  operation of the Trust, including without limitation, costs
                  and expenses of accountants, attorneys, statistical or
                  bookkeeping services, expenses for printing and engraving and
                  computing or accounting equipment, paying agent(s),
                  registrar(s), transfer agent(s), duplicating, travel and
                  telephone and other telecommunications expenses and costs and
                  expenses incurred in connection with the acquisition,
                  financing, and disposition of assets of the Trust;

         (c)      be primarily and fully liable for any indemnification
                  obligations arising with respect to the Declaration;

         (d)      pay any and all taxes (other than United States withholding
                  taxes attributable to the Trust or its assets) and all
                  liabilities, costs and expenses with respect to such taxes of
                  the Trust; and

         (e)      pay all other fees, expenses, debts and obligations (other
                  than in respect of the Trust Securities) related to the Trust.

         SECTION 3.10 PAYMENT UPON RESIGNATION OR REMOVAL.

         Upon termination of this Indenture or the removal or resignation of the
Debenture Trustee, unless otherwise stated, the Corporation shall pay to the
Debenture Trustee all amounts accrued and owing to the Debenture Trustee to the
date of such termination, removal or resignation. Upon termination of the
Declaration or the removal or resignation of the Delaware Trustee or the
Property Trustee, as the case may be, pursuant to Section 5.6 of the
Declaration, the Corporation shall pay to the Delaware Trustee or the Property
Trustee, as the case may be, all amounts accrued and owing to such trustee(s) to
the date of such termination, removal or resignation.


                                   ARTICLE IV
                   LIST OF SECURITYHOLDERS AND REPORTS BY THE
                      CORPORATION AND THE DEBENTURE TRUSTEE

         SECTION 4.01 LIST OF SECURITYHOLDERS.

         The Corporation covenants and agrees that it will furnish or cause to
be furnished to the Debenture Trustee:

         (a)      on a semi-annual basis on each regular record date for the
                  Securities, a list, in such form as the Debenture Trustee may
                  reasonably require, of the names and addresses of the
                  Securityholders as of such record date; and



                                       23
<PAGE>   31

         (b)      at such other times as the Debenture Trustee may request in
                  writing, within 30 days after the receipt by the Corporation,
                  of any such request, a list of similar form and content as of
                  a date not more than 15 days prior to the time such list is
                  furnished,

except that, no such lists need be furnished so long as the Debenture Trustee is
in possession thereof by reason of its acting as security registrar for the
Securities.

         SECTION 4.02 PRESERVATION AND DISCLOSURE OF LISTS.

         (a) The Debenture Trustee shall preserve, in as current a form as is
reasonably practicable, all information as to the names and addresses of the
holders of the Securities (1) contained in the most recent list furnished to it
as provided in Section 4.01 or (2) received by it in the capacity of security
registrar (if so acting) hereunder. The Debenture Trustee may destroy any list
furnished to it as provided in Section 4.01 upon receipt of a new list so
furnished.

         (b) In case three or more holders of Securities (hereinafter referred
to as "applicants") apply in writing to the Debenture Trustee and furnish to the
Debenture Trustee reasonable proof that each such applicant has owned a Security
for a period of at least six months preceding the date of such application, and
such application states that the applicants desire to communicate with other
holders of Securities or with holders of all Securities with respect to their
rights under this Indenture and is accompanied by a copy of the form of proxy or
other communication which such applicants propose to transmit, then the
Debenture Trustee shall, within five Business Days after the receipt of such
application, at its election, either:

                  (1)      afford such applicants access to the information
                           preserved at the time by the Debenture Trustee in
                           accordance with the provisions of subsection (a) of
                           this Section 4.02, or

                  (2)      inform such applicants as to the approximate number
                           of holders of all Securities whose names and
                           addresses appear in the information preserved at the
                           time by the Debenture Trustee in accordance with the
                           provisions of subsection (a) of this Section 4.02,
                           and as to the approximate cost of mailing to such
                           Securityholders the form of proxy or other
                           communication, if any, specified in such application.

         If the Debenture Trustee shall elect not to afford such applicants
access to such information, the Debenture Trustee shall, upon the written
request of such applicants, mail to each Securityholder whose name and address
appear in the information preserved at the time by the Debenture Trustee in
accordance with the provisions of subsection (a) of this Section 4.02 a copy of
the form of proxy or other communication which is specified in such request with
reasonable promptness after a tender to the Debenture Trustee of the material to
be mailed and of payment, or provision for the payment, of the reasonable
expenses of mailing, unless within five Business Days after such tender, the
Debenture Trustee shall mail to such applicants and file with the Commission,
together with a copy of the material to be mailed, a written statement to



                                       24
<PAGE>   32

the effect that, in the opinion of the Debenture Trustee, such mailing would be
contrary to the best interests of the holders of Securities or would be in
violation of applicable law. Such written statement shall specify the basis of
such opinion. If the Commission, after opportunity for a hearing upon the
objections specified in the written statement so filed, shall enter an order
refusing to sustain any of such objections or if, after the entry of an order
sustaining one or more of such objections, the Commission shall find, after
notice and opportunity for hearing, that all the objections so sustained have
been met and shall enter an order so declaring, the Debenture Trustee shall mail
copies of such material to all such Securityholders with reasonable promptness
after the entry of such order and the renewal of such tender; otherwise the
Debenture Trustee shall be relieved of any obligation or duty to such applicants
respecting their application.

         (c) Each and every holder of Securities, by receiving and holding the
same, agrees with the Corporation and the Debenture Trustee that neither the
Corporation nor the Debenture Trustee nor any paying agent shall be held
accountable by reason of the disclosure of any such information as to the names
and addresses of the holders of Securities in accordance with the provisions of
subsection (b) of this Section 4.02, regardless of the source from which such
information was derived, and that the Debenture Trustee shall not be held
accountable by reason of mailing any material pursuant to a request made under
said subsection (b).

         SECTION 4.03 REPORTS BY THE CORPORATION.

         (a) The Corporation covenants and agrees to file with the Debenture
Trustee, within 15 days after the date on which the Corporation is required to
file the same with the Commission, copies of the annual reports and of the
information, documents and other reports (or copies of such portions of any of
the foregoing as said Commission may from time to time by rules and regulations
prescribe) which the Corporation may be required to file with the Commission
pursuant to Section 13 or Section 15(d) of the Exchange Act; or, if the
Corporation is not required to file information, documents or reports pursuant
to either of such sections, then to provide to the Debenture Trustee, such of
the supplementary and periodic information, documents and reports which would
have been required pursuant to Section 13 of the Exchange Act in respect of a
security listed and registered on a national securities exchange as may be
prescribed from time to time in such rules and regulations. The Corporation also
covenants and agrees to comply with the provisions of Section 314(a) of the
Trust Indenture Act.

         (b) The Corporation covenants and agrees to file with the Debenture
Trustee and the Commission, in accordance with the rules and regulations
prescribed from time to time by said Commission, such additional information,
documents and reports with respect to compliance by the Corporation with the
conditions and covenants provided for in this Indenture as may be required from
time to time by such rules and regulations.

         (c) The Corporation covenants and agrees to transmit by mail to all
holders of Securities, as the names and addresses of such holders appear upon
the Security Register, within 30 days after the filing thereof with the
Debenture Trustee, such summaries of any information, documents and reports
required to be filed by the Corporation pursuant to subsections (a) and (b) of
this Section 4.03 as may be required by rules and regulations prescribed from
time to time by the Commission.

                                       25
<PAGE>   33

         (d) Delivery of such reports, information and documents to the
Debenture Trustee is for informational purposes only and the Debenture Trustee's
receipt of such shall not constitute constructive notice of any information
contained therein or determinable from information contained therein, including
the Corporation's compliance with any of its covenants hereunder (as to which
the Debenture Trustee is entitled to rely exclusively on Officers'
Certificates).

         (e) So long as is required for an offer or sale of the Securities to
qualify for an exemption under Rule 144A under the Securities Act, the
Corporation shall, upon request, provide the information required by clause
(d)(4) thereunder to each Securityholder and to each beneficial owner and
prospective purchaser of Securities identified by each Securityholder of
Restricted Securities, unless such information is furnished to the Commission
pursuant to Section 13 or l5(d) of the Exchange Act.

         SECTION 4.04 REPORTS BY THE DEBENTURE TRUSTEE.

         (a) The Debenture Trustee shall transmit to Securityholders such
reports concerning the Debenture 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. If required by Section 313(a) of the Trust
Indenture Act, the Debenture Trustee shall, on or before July 15 of each year,
commencing July 15, 2001, deliver to Securityholders a brief report, dated as of
each such date which complies with the provisions of such Section 313(a).

         (b) A copy of each such report shall, at the time of such transmission
to Securityholders, be filed by the Debenture Trustee with each stock exchange,
if any, upon which the Securities are listed, with the Commission and with the
Corporation. The Corporation will promptly notify the Debenture Trustee when the
Securities are listed on any stock exchange.


                                    ARTICLE V
                      REMEDIES OF THE DEBENTURE TRUSTEE AND
                      SECURITYHOLDERS UPON EVENT OF DEFAULT

         SECTION 5.01 EVENTS OF DEFAULT.

         One or more of the following events of default shall constitute an
Event of Default hereunder (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):

         (a)      default in the payment of any interest (including Compounded
                  Interest and Additional Sums, if any) or Liquidated Damages,
                  if any, on the Securities or any Other Debentures (about which
                  a Responsible Officer of the Debenture Trustee has actual
                  knowledge) when due, and continuance of such default for a
                  period of 30 days; PROVIDED, HOWEVER, that a valid extension
                  of an interest payment period



                                       26
<PAGE>   34

                  by the Corporation in accordance with the terms hereof or
                  thereof shall not constitute a default in the payment of
                  interest for this purpose; or

         (b)      default in the payment of any principal of (or premium, if
                  any, on) the Securities or any Other Debentures (about which a
                  Responsible Officer of the Debenture Trustee has actual
                  knowledge) when due, whether at maturity, upon prepayment, by
                  declaration of acceleration of maturity or otherwise; or

         (c)      default in the performance, or breach of any covenant or
                  warranty of the Corporation in this Indenture (other than a
                  covenant or warranty a default in whose performance or whose
                  breach is elsewhere in this Section specifically dealt with),
                  and continuance of such default or breach for a period of 90
                  days after there has been given, by registered or certified
                  mail, to the Corporation by the Debenture Trustee or to the
                  Corporation and the Debenture Trustee by the holders of at
                  least 25% in aggregate principal amount of the outstanding
                  Securities a written notice specifying such default or breach
                  and requiring it to be remedied and stating that such notice
                  is a "Notice of Default" hereunder; or

         (d)      a court having jurisdiction in the premises shall enter a
                  decree or order for relief in respect of the Corporation in an
                  involuntary case under any applicable bankruptcy, insolvency
                  or other similar law now or hereafter in effect, or appointing
                  a receiver, liquidator, assignee, custodian, trustee,
                  sequestrator (or similar official) of the Corporation or for
                  any substantial part of its property, or ordering the
                  winding-up or liquidation of its affairs and such decree or
                  order shall remain unstayed and in effect for a period of 90
                  consecutive days; or

         (e)      the Corporation shall commence a voluntary case under any
                  applicable bankruptcy, insolvency or other similar law now or
                  hereafter in effect, shall consent to the entry of an order
                  for relief in an involuntary case under any such law, or shall
                  consent to the appointment of or taking possession by a
                  receiver, liquidator, assignee, trustee, custodian,
                  sequestrator (or other similar official) of the Corporation or
                  of any substantial part of its property, or shall make any
                  general assignment for the benefit of creditors, or shall fail
                  generally to pay its debts as they become due.

         If an Event of Default with respect to Securities at the time
outstanding occurs and is continuing, then in every such case the Debenture
Trustee or the holders of not less than 25% in aggregate principal amount of the
Securities then outstanding may declare the principal amount of all Securities
to be due and payable immediately, by a notice in writing to the Corporation
(and to the Debenture Trustee if given by the holders of the outstanding
Securities), and upon any such declaration the same shall become immediately due
and payable.

         The foregoing provisions, however, are subject to the condition that
if, at any time after the principal of the Securities shall have been so
declared due and payable, and before any judgment or decree for the payment of
the moneys due shall have been obtained or entered as hereinafter provided, (i)
the Corporation shall pay or shall deposit with the Debenture Trustee a



                                       27
<PAGE>   35

sum sufficient to pay (A) all matured installments of interest (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
on all the Securities and the principal of and premium, if any, on any and all
Securities which shall have become due otherwise than by acceleration (with
interest upon such principal and premium, if any, and, to the extent that
payment of such interest is enforceable under applicable law, on overdue
installments of interest, at the same rate as the rate of interest specified in
the Securities to the date of such payment or deposit) and (B) such amount as
shall be sufficient to cover compensation due to the Debenture Trustee and each
predecessor Debenture Trustee, their respective agents, attorneys and counsel,
pursuant to Section 6.06, and (ii) any and all Events of Default under the
Indenture, other than the non-payment of the principal of the Securities which
shall have become due solely by such declaration of acceleration, shall have
been cured, waived or otherwise remedied as provided herein, then, in every such
case, the holders of a majority in aggregate principal amount of the Securities
then outstanding, by written notice to the Corporation and to the Debenture
Trustee, may 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 shall impair any right consequent thereon.

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

         SECTION 5.02 PAYMENT OF SECURITIES ON DEFAULT; SUIT THEREFOR.

         The Corporation covenants that (a) in case default shall be made in the
payment of any installment of interest (including Compounded Interest and
Additional Sums, if any) and Liquidated Damages, if any, on any of the
Securities as and when the same shall become due and payable, and such default
shall have continued for a period of 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
Securities as and when the same shall have become due and payable, whether at
maturity of the Securities or upon prepayment or by declaration or otherwise,
then, upon demand of the Debenture Trustee, the Corporation will pay to the
Debenture Trustee, for the benefit of the holders of the Securities, the whole
amount that then shall have become due and payable on all such Securities for
principal and premium, if any, or interest (including Compounded Interest and
Additional Sums, if any) and Liquidated Damages, if any, or both, 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
and, if the Securities are held by the Trust or a trustee of such Trust, without
duplication of any other amounts paid by the Trust or a trustee in respect
thereof) upon the overdue installments of interest (including Compounded
Interest and Additional Sums, if any) and Liquidated Damages, if any, at the
rate borne by the Securities; and, in addition thereto, such further amount as
shall be sufficient to cover the costs and expenses of collection, including
reasonable compensation to the Debenture Trustee, its agents, attorneys and
counsel, and any other amount due to the Debenture Trustee pursuant to Section
6.06.



                                       28
<PAGE>   36

         In case the Corporation shall fail forthwith to pay such amounts upon
such demand, the Debenture 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 Corporation or any other
obligor on the Securities and collect in the manner provided by law out of the
property of the Corporation or any other obligor on the Securities, wherever
situated, the moneys adjudged or decreed to be payable.

         In case there shall be pending proceedings for the bankruptcy or for
the reorganization of the Corporation or any other obligor on the Securities
under Title 11, United States Code, or any other applicable law, or in case a
receiver or trustee shall have been appointed for the property of the
Corporation or such other obligor, or in the case of any other similar judicial
proceedings relative to the Corporation or other obligor upon the Securities, or
to the creditors or property of the Corporation or such other obligor, the
Debenture Trustee, irrespective of whether the principal of the Securities shall
then be due and payable as therein expressed or by declaration or otherwise and
irrespective of whether the Debenture Trustee shall have made any demand
pursuant to the provisions of this Section 5.02, 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 and interest owing and unpaid
in respect of the Securities 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 Debenture Trustee (including any
claim for amounts due to the Debenture Trustee pursuant to Section 6.06) and of
the Securityholders allowed in such judicial proceedings relative to the
Corporation or any other obligor on the Securities, or to the creditors or
property of the Corporation or such other obligor, unless prohibited by
applicable law and regulations, to vote on behalf of the holders of the
Securities in any election of a trustee or a standby trustee in arrangement,
reorganization, liquidation or other bankruptcy or insolvency proceedings or
person performing similar functions in comparable proceedings, and to collect
and receive any moneys or other property payable or deliverable on any such
claims, and to distribute the same after the deduction of its charges and
expenses; and any receiver, assignee or trustee in bankruptcy or reorganization
is hereby authorized by each of the Securityholders to make such payments to the
Debenture Trustee, and, in the event that the Debenture Trustee shall consent to
the making of such payments directly to the Securityholders, to pay to the
Debenture Trustee such amounts as shall be sufficient to cover reasonable
compensation to, and expenses of, the Debenture Trustee, each predecessor
Debenture Trustee and their respective agents, attorneys and counsel, and all
other amounts due to the Debenture Trustee pursuant to Section 6.06.

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



                                       29
<PAGE>   37

         All rights of action and of asserting claims under this Indenture, or
under any of the Securities, may be enforced by the Debenture Trustee without
the possession of any of the Securities, or the production thereof on any trial
or other proceeding relative thereto, and any such suit or proceeding instituted
by the Debenture Trustee shall be brought in its own name as trustee of an
express trust, and any recovery of judgment shall be for the ratable benefit of
the holders of the Securities.

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

         SECTION 5.03 APPLICATION OF MONEYS COLLECTED BY DEBENTURE TRUSTEE.

         Any moneys collected by the Debenture Trustee shall be applied in the
following order, at the date or dates fixed by the Debenture Trustee for the
distribution of such moneys, upon presentation of the Securities in respect of
which moneys have been collected, and stamping thereon the payment, if only
partially paid, and upon surrender thereof if fully paid:

         First: To the payment of costs and expenses of collection applicable to
the Securities and all other amounts due to the Debenture Trustee under Section
6.06;

         Second: To the payment of all Senior Indebtedness of the Corporation if
and to the extent required by Article XV;

         Third: To the payment of the amounts then due and unpaid upon
Securities for principal of (and premium, if any) and interest (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
on the Securities, in respect of which or for the benefit of which money has
been collected, ratably, without preference of priority of any kind, according
to the amounts due on such Securities for principal (and premium, if any) and
interest, respectively; and

         Fourth: To the Corporation.

         SECTION 5.04 PROCEEDINGS BY SECURITYHOLDERS.

         No holder of any Security shall have any right by virtue of or by
availing itself of 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 or trustee, or for any other
remedy hereunder, unless such holder previously shall have given to the
Debenture Trustee written notice of an Event of Default and of the continuance
thereof with respect to the Securities specifying such Event of Default, as
hereinbefore provided, and unless also the holders of not less than 25% in
aggregate principal amount of the Securities then outstanding shall have made
written request upon the Debenture Trustee to institute such action, suit or
proceeding in its own name as Debenture Trustee hereunder and shall have offered
to the Debenture Trustee such



                                       30
<PAGE>   38

reasonable indemnity as it may require against the costs, expenses and
liabilities to be incurred therein or thereby, and the Debenture Trustee for 60
days after its receipt of such notice, request and offer of indemnity shall have
failed to institute any such action, suit or proceeding, it being understood and
intended, and being expressly covenanted by the taker and holder of every
Security with every other taker and holder and the Debenture Trustee, that no
one or more holders of Securities shall have any right in any manner whatever by
virtue of or by availing itself of any provision of this Indenture to affect,
disturb or prejudice the rights of any other holder of Securities, 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 Securities.

         Notwithstanding any other provisions in this Indenture, however, the
right of any holder of any Security to receive payment of the principal of (and
premium, if any) and interest on (including Compounded Interest and Additional
Sums, if any) and Liquidated Damages, if any, on such Security, on or after the
same shall have become due and payable, or to institute suit for the enforcement
of any such payment, shall not be impaired or affected without the consent of
such holder, and by accepting a Security hereunder it is expressly understood,
intended and covenanted by the taker and holder of every Security with every
other such taker and holder and the Debenture Trustee, that no one or more
holders of Securities shall have any right in any manner whatsoever by virtue or
by availing itself of any provision of this Indenture to affect, disturb or
prejudice the rights of the holders of any other Securities, 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 Securities. For the
protection and enforcement of the provisions of this Section, each and every
Securityholder and the Debenture Trustee shall be entitled to such relief as can
be given either at law or in equity.

         The Corporation and the Debenture Trustee acknowledge that pursuant to
the Declaration, the holders of Capital Securities are entitled, in the
circumstances and subject to the limitations set forth therein, to commence a
Direct Action with respect to any Event of Default referred to in clause (a) or
(b) of Section 5.01.

         SECTION 5.05 PROCEEDINGS BY DEBENTURE TRUSTEE.

         In case an Event of Default occurs with respect to Securities and is
continuing, the Debenture Trustee may in its discretion proceed to protect and
enforce the rights vested in it by this Indenture by such appropriate judicial
proceedings as the Debenture Trustee shall deem most effectual 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 Debenture Trustee by this Indenture or by law.

         SECTION 5.06 REMEDIES CUMULATIVE AND CONTINUING.



                                       31
<PAGE>   39

         All powers and remedies given by this Article V to the Debenture
Trustee or to the Securityholders shall, to the extent permitted by law, be
deemed cumulative and not exclusive of any other powers and remedies available
to the Debenture Trustee or the holders of the Securities, by judicial
proceedings or otherwise, to enforce the performance or observance of the
covenants and agreements contained in this Indenture or otherwise established
with respect to the Securities, and no delay or omission of the Debenture
Trustee or of any holder of any of the Securities to exercise any right or power
accruing upon any 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 an acquiescence therein; and, subject to the provisions of Section
5.04, every power and remedy given by this Article V or by law to the Debenture
Trustee or to the Securityholders may be exercised from time to time, and as
often as shall be deemed expedient, by the Debenture Trustee or by the
Securityholders.

         SECTION 5.07 DIRECTION OF PROCEEDINGS AND WAIVER OF DEFAULTS BY
MAJORITY OF SECURITYHOLDERS.

         The holders of a majority in aggregate principal amount of the
Securities at the time outstanding shall have the right to direct the time,
method, and place of conducting any proceeding for any remedy available to the
Debenture Trustee, or exercising any trust or power conferred on the Debenture
Trustee; PROVIDED, HOWEVER, that (subject to the provisions of Section 6.01) the
Debenture Trustee shall have the right to decline to follow any such direction
if the Debenture Trustee shall determine that the action so directed would be
unjustly prejudicial to the holders not taking part in such direction or if the
Debenture Trustee being advised by counsel determines that the action or
proceeding so directed may not lawfully be taken or if the Debenture Trustee in
good faith by one of its Responsible Officers shall determine that the action or
proceedings so directed would involve the Debenture Trustee in personal
liability. Prior to any declaration accelerating the maturity of the Securities,
the holders of a majority in aggregate principal amount of the Securities at the
time outstanding may on behalf of the holders of all of the Securities waive any
past Default or Event of Default and its consequences except a Default (a) in
the payment of principal of (or premium, if any) or interest on (including
Compounded Interest and Additional Sums, if any) or Liquidated Damages, if any,
on any of the Securities (unless such default has been cured and a sum
sufficient to pay all matured installments of interest (including Compounded
Interest and Additional Sums, if any) and principal (and premium, if any) due
otherwise than by acceleration has been deposited with the Debenture Trustee) or
(b) in respect of covenants or provisions hereof which cannot be modified or
amended without the consent of the holder of each Security affected; PROVIDED,
HOWEVER, that if the Securities are held by the Property Trustee, such waiver or
modification to such waiver shall not be effective until the holders of a
majority in aggregate liquidation amount of Trust Securities shall have
consented to such waiver or modification to such waiver; PROVIDED, FURTHER, that
if the consent of the holder of each outstanding Security is required, such
waiver shall not be effective until each holder of the Trust Securities shall
have consented to such waiver. Upon any such waiver, the Default covered thereby
shall be deemed to be cured for all purposes of this Indenture and the
Corporation, the Debenture Trustee and the holders of the Securities shall be
restored to their former positions and rights hereunder, respectively; but no
such waiver shall extend to any subsequent or other Default or impair any right
consequent thereon. Whenever any Default or Event of Default hereunder shall
have been waived as permitted by this Section



                                       32
<PAGE>   40

5.07, said Default or Event of Default shall for all purposes of the Securities
and this Indenture be deemed to have been cured and to be not continuing.

         SECTION 5.08  NOTICE OF DEFAULTS

         (a) The Debenture Trustee shall, within 90 days after the occurrence of
a Default with respect to the Securities actually known to a Responsible Officer
of the Debenture Trustee, mail to all Securityholders, as the names and
addresses of such holders appear upon the Security Register, notice of all such
Defaults, unless such Default shall have been cured before the giving of such
notice (the term "Default" for the purpose of this Section 5.08 being hereby
defined to be any of the events specified in clauses (a), (b), (c), (d) and (e)
of Section 5.01, not including periods of grace, if any, provided for therein,
and irrespective of the giving of written notice specified in clause (c) of
Section 5.01); PROVIDED, HOWEVER, that, except in the case of Default in the
payment of the principal of (or premium, if any) or interest (including
Compounded Interest or Additional Sums, if any) or Liquidated Damages, if any,
on any of the Securities, the Debenture Trustee shall be protected in
withholding such notice if and so long as the board of directors, the executive
committee, or a trust committee of directors and/or Responsible Officers of the
Debenture Trustee in good faith determines that the withholding of such notice
is in the interests of the Securityholders; PROVIDED, FURTHER, that in the case
of any Default of the character specified in Section 5.01(c), no such notice to
Securityholders shall be given until at least 60 days after the occurrence
thereof, but shall be given within 90 days after such occurrence.

         (b) Within ten Business Days after the occurrence of any Event of
Default actually known to a Responsible Officer of the Debenture Trustee, the
Debenture Trustee shall transmit notice of such Event of Default to all
Securityholders as their names and addresses appear on the Security Register,
unless such Event of Default shall have been cured or waived.

         SECTION 5.09 UNDERTAKING TO PAY COSTS.

         All parties to this Indenture agree, and each holder of any Security by
its acceptance thereof shall be 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 Debenture Trustee for any action
taken or omitted by it as Debenture 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;
but the provisions of this Section 5.09 shall not apply to any suit instituted
by the Debenture Trustee, to any suit instituted by any Securityholder, or group
of Securityholders, holding in the aggregate more than 10% in aggregate
principal amount of the Securities outstanding, or to any suit instituted by any
Securityholder for the enforcement of the payment of the principal of (or
premium, if any) or interest (including Compounded Interest and Additional Sums,
if any) or Liquidated Damages, if any, on any Security against the Corporation
on or after the same shall have become due and payable.

                                   ARTICLE VI

                                       33
<PAGE>   41

                        CONCERNING THE DEBENTURE TRUSTEE

         SECTION 6.01 DUTIES AND RESPONSIBILITIES OF DEBENTURE TRUSTEE.

         With respect to the holders of the Securities issued hereunder, the
Debenture Trustee, prior to the occurrence of an Event of Default (which, other
than in the case of Sections 5.01(a) and 5.01(b) hereof, is known to the
Debenture Trustee) and after the curing or waiving of all such 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
(which, other than in the case of Sections 5.01(a) and 5.01(b) hereof, is known
to the Debenture Trustee) has occurred (which has not been cured or waived), the
Debenture Trustee shall exercise such of the rights and powers vested in it by
this Indenture, and use the same degree of care and skill in their exercise as a
prudent person would exercise or use under the circumstances in the conduct of
his or her own affairs.

         No provision of this Indenture shall be construed to relieve the
Debenture 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 (which, other
                  than in the case of Sections 5.01(a) and 5.01(b) hereof, is
                  known to the Debenture Trustee) and after the curing or
                  waiving of all such Events of Default which may have occurred,

                  (1)      the duties and obligations of the Debenture Trustee
                           shall be determined solely by the express provisions
                           of this Indenture, and the Debenture 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 against
                           the Debenture Trustee; and

                  (2)      in the absence of bad faith on the part of the
                           Debenture Trustee, the Debenture Trustee may
                           conclusively rely, as to the truth of the statements
                           and the correctness of the opinions expressed
                           therein, upon any certificate or opinion furnished to
                           the Debenture Trustee and conforming to the
                           requirements of this Indenture; but, in the case of
                           any such certificate or opinion which by any
                           provision hereof is specifically required to be
                           furnished to the Debenture Trustee, the Debenture
                           Trustee shall be under a duty to examine the same to
                           determine whether or not it conforms on its face to
                           the requirements of this Indenture;

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

         (c)      the Debenture 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 direction of the



                                       34
<PAGE>   42

                  Securityholders pursuant to Section 5.07, relating to the
                  time, method and place of conducting any proceeding for any
                  remedy available to the Debenture Trustee, or exercising any
                  trust or power conferred upon the Debenture Trustee, under
                  this Indenture.

         None of the provisions contained in this Indenture shall require the
Debenture 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 it reasonably believes that the repayment of
such funds or liability is not reasonably assured to it under the terms of this
Indenture or adequate indemnity against such risk is not reasonably assured to
it.

         SECTION 6.02 RELIANCE ON DOCUMENTS, OPINIONS, ETC.

         Except as otherwise provided in Section 6.01:

         (a)      the Debenture Trustee may conclusively rely and shall be
                  protected in acting or refraining from acting upon any
                  resolution, certificate, statement, instrument, opinion,
                  report, notice, request, consent, order, bond, note, debenture
                  or other paper or document believed by it 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 Corporation
                  mentioned herein may be sufficiently evidenced by an Officers'
                  Certificate (unless other evidence in respect thereof be
                  herein specifically prescribed); and any Board Resolution may
                  be evidenced to the Debenture Trustee by a copy thereof
                  certified by the Secretary or an Assistant Secretary of the
                  Corporation;

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

         (d)      the Debenture 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 Securityholders,
                  pursuant to the provisions of this Indenture, unless such
                  Securityholders shall have offered to the Debenture Trustee
                  reasonable and sufficient security or indemnity against the
                  costs, expenses and liabilities which may be incurred therein
                  or thereby;

         (e)      the Debenture Trustee shall not be liable for any action taken
                  or omitted by it in good faith and believed by it to be
                  authorized or within the discretion or rights or powers
                  conferred upon it by this Indenture; nothing contained herein
                  shall, however, relieve the Debenture Trustee of the
                  obligation, upon the occurrence of an Event of Default (which,
                  other than in the case of Sections 5.01(a) and 5.01(b) hereof,
                  is known to the Debenture Trustee) (that has not been cured or
                  waived), to exercise such of the rights and powers vested in
                  it by this Indenture, and to use the



                                       35
<PAGE>   43

                  same degree of care and skill in its exercise as a prudent
                  person would exercise or use under the circumstances in the
                  conduct of his or her own affairs;

         (f)      the Debenture 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, consent, order, approval, bond,
                  debenture, coupon or other paper or document, unless requested
                  in writing to do so by the holders of a majority in aggregate
                  principal amount of the outstanding Securities; PROVIDED,
                  HOWEVER, that if the payment within a reasonable time to the
                  Debenture Trustee of the costs, expenses or liabilities likely
                  to be incurred by it in the making of such investigation is,
                  in the opinion of the Debenture Trustee, not reasonably
                  assured to the Debenture Trustee by the security afforded to
                  it by the terms of this Indenture, the Debenture Trustee may
                  require reasonable indemnity against such expense or liability
                  as a condition to so proceeding;

         (g)      the Debenture Trustee may execute any of the trusts or powers
                  hereunder or perform any duties hereunder either directly or
                  by or through agents (including any Authenticating Agent) or
                  attorneys, and the Debenture Trustee shall not be responsible
                  for any misconduct or negligence on the part of any such agent
                  or attorney appointed by it with due care;

         (h)      the Debenture Trustee shall not be charged with knowledge of
                  any Default or Event of Default unless (1) such Default or
                  Event of Default falls within Section 5.01(a) (other than a
                  default with respect to the payment or nonpayment of
                  Compounded Interest, Liquidated Damages or Additional Sums) or
                  Section 5.01(b) of the Indenture, (2) a Responsible Officer
                  shall have actual knowledge of such Default or Event of
                  Default or (3) written notice of such Default or Event of
                  Default shall have been given to the Debenture Trustee by the
                  Corporation or any other obligor on the Securities or by any
                  holder of the Securities; and

         (i)      the Debenture Trustee shall not be liable for any action
                  taken, suffered or omitted by it in good faith, without
                  negligence or willful misconduct and believed by it to be
                  authorized or within the discretion or rights or powers
                  conferred upon it by this Indenture.

         SECTION 6.03 NO RESPONSIBILITY FOR RECITALS, ETC.

         The recitals contained herein and in the Securities (except in the
certificate of authentication of the Debenture Trustee or the Authenticating
Agent) shall be taken as the statements of the Corporation, and the Debenture
Trustee and the Authenticating Agent assume no responsibility for the
correctness of the same. The Debenture Trustee and the Authenticating Agent make
no representations as to the validity or sufficiency of this Indenture or of the
Securities. The Debenture Trustee and the Authenticating Agent shall not be
accountable for the use or application by the Corporation of any Securities or
the proceeds of any Securities authenticated and delivered by the Debenture
Trustee or the Authenticating Agent in conformity with the provisions of this
Indenture.



                                       36
<PAGE>   44

         SECTION 6.03 DEBENTURE TRUSTEE, AUTHENTICATING AGENT, PAYING AGENTS,
TRANSFER AGENTS AND REGISTRAR MAY OWN SECURITIES.

         The Debenture Trustee or any Authenticating Agent or any paying agent
or any transfer agent or any security registrar for the Securities, in its
individual or any other capacity, may become the owner or pledgee of Securities
with the same rights it would have if it were not Debenture Trustee,
Authenticating Agent, paying agent, transfer agent or security registrar for the
Securities.

         SECTION 6.04 MONEYS TO BE HELD IN TRUST.

         Subject to the provisions of Section 11.04, all moneys received by the
Debenture Trustee or any paying agent shall, until used or applied as herein
provided, be held in trust for the purpose for which they were received, but
need not be segregated from other funds except to the extent required by law.
The Debenture Trustee and any paying agent shall be under no liability for
interest on any money received by it hereunder except as otherwise agreed in
writing with the Corporation. So long as no Event of Default shall have occurred
and be continuing, all interest allowed on any such moneys shall be paid from
time to time upon the written order of the Corporation, signed by an Officer
thereof.

         SECTION 6.05 COMPENSATION AND EXPENSES OF DEBENTURE TRUSTEE.

         The Corporation, as issuer of Securities under this Indenture,
covenants and agrees to pay to the Debenture Trustee from time to time, and the
Debenture Trustee shall be entitled to, such compensation as shall be agreed to
in writing between the Corporation and the Debenture Trustee (which shall not be
limited by any provision of law in regard to the compensation of a trustee of an
express trust), and the Corporation will pay or reimburse the Debenture Trustee
upon its request for all reasonable expenses, disbursements and advances
incurred or made by the Debenture 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 or bad faith. The Corporation also covenants to indemnify each of
the Debenture Trustee (including in its individual capacity) and any predecessor
Debenture Trustee (and its officers, agents, directors and employees) for, and
to hold it harmless against, any and all loss, damage, claim, action, suit,
liability or expense including taxes (other than taxes based on the income of
the Debenture Trustee) incurred without negligence or bad faith on the part of
the Debenture Trustee and arising out of or in connection with the acceptance or
administration of this trust, including the costs and expenses of defending
itself against any claim of liability. The obligations of the Corporation under
this Section 6.06 to compensate and indemnify the Debenture Trustee and to pay
or reimburse the Debenture Trustee for expenses, disbursements and advances
shall constitute additional indebtedness hereunder. Such additional indebtedness
shall be secured by a lien prior to that of the Securities upon all property and
funds held or collected by the Debenture Trustee as such, except funds held in
trust for the benefit of the holders of particular Securities.



                                       37
<PAGE>   45

         When the Debenture Trustee incurs expenses or renders services in
connection with an Event of Default specified in Section 5.01(d) or Section
5.01(e), the expenses (including the reasonable charges and expenses of its
counsel) and the compensation for its services are intended to constitute
expenses of administration under any applicable federal or state bankruptcy,
insolvency or other similar law.

         The provisions of this Section shall survive the resignation or removal
of the Debenture Trustee and the defeasance or other termination of this
Indenture.

         SECTION 6.06 OFFICERS' CERTIFICATE AS EVIDENCE.

         Except as otherwise provided in Sections 6.01 and 6.02, whenever in the
administration of the provisions of this Indenture the Debenture 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 is herein specifically prescribed) may, in the absence of
negligence or bad faith on the part of the Debenture Trustee, be deemed to be
conclusively proved and established by an Officers' Certificate delivered to the
Debenture Trustee, and such Officers' Certificate, in the absence of negligence
or bad faith on the part of the Debenture Trustee, shall be full warrant to the
Debenture Trustee for any action taken or omitted by it under the provisions of
this Indenture upon the faith thereof.

         SECTION 6.07 CONFLICTING INTEREST OF DEBENTURE TRUSTEE.

         If the Debenture Trustee has or shall acquire any "conflicting
interest" within the meaning of Section 310(b) of the Trust Indenture Act, the
Debenture Trustee and the Corporation shall in all respects comply with the
provisions of Section 310(b) of the Trust Indenture Act.

         SECTION 6.08 ELIGIBILITY OF DEBENTURE TRUSTEE.

         The Debenture Trustee hereunder shall at all times be a Person
organized and doing business under the laws of the United States of America or
any state or territory thereof or of the District of Columbia, or a corporation
or other Person permitted to act as trustee by the Commission authorized under
such laws to exercise corporate trust powers, having a combined capital and
surplus of at least fifty million U.S. dollars ($50,000,000) and subject to
supervision or examination by federal, state, territorial, or District of
Columbia authority. If such Person publishes reports of condition at least
annually, pursuant to law or to the requirements of the aforesaid supervising or
examining authority, then for the purposes of this Section 6.09 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.

         The Corporation may not, nor may any Person directly or indirectly
controlling, controlled by, or under common control with the Corporation, serve
as Debenture Trustee.



                                       38
<PAGE>   46

         In case at any time the Debenture Trustee shall cease to be eligible in
accordance with the provisions of this Section 6.09, the Debenture Trustee shall
resign immediately in the manner and with the effect specified in Section 6.10.

         SECTION 6.9 RESIGNATION OR REMOVAL OF DEBENTURE TRUSTEE.

         (a) The Debenture Trustee, or any trustee or trustees hereafter
appointed, may at any time resign by giving written notice of such resignation
to the Corporation and by mailing notice thereof to the holders of the
Securities at their addresses as they shall appear on the Security Register.
Upon receiving such notice of resignation, the Corporation shall promptly
appoint a successor trustee or trustees, in accordance with the provisions of
Section 6.09, by written instrument, in duplicate, one copy of which instrument
shall be delivered to the resigning Debenture Trustee and one copy to the
successor trustee. If no successor trustee shall have been so appointed and have
accepted appointment within 60 days after the mailing of such notice of
resignation to the affected Securityholders, the resigning Debenture Trustee may
petition any court of competent jurisdiction for the appointment of a successor
trustee, or any Securityholder who has been a bona fide holder of a Security for
at least six months may, subject to the provisions of Section 5.09, 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:

                  (1)      the Debenture Trustee shall fail to comply with the
                           provisions of Section 6.08 after written request
                           therefor by the Corporation or by any Securityholder
                           who has been a bona fide holder of a Security or
                           Securities for at least six months, or

                  (2)      the Debenture Trustee shall cease to be eligible in
                           accordance with the provisions of Section 6.09 and
                           shall fail to resign after written request therefor
                           by the Corporation or by any Securityholder who has
                           been a bona fide holder of a Security or Securities
                           for at least six months, or

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

then, in any such case, the Corporation may remove the Debenture Trustee and
appoint a successor trustee, in accordance with the provisions of Section 6.10,
by written instrument, in duplicate, one copy of which instrument shall be
delivered to the Debenture Trustee so removed and one copy to the successor
trustee, or, subject to the provisions of Section 5.09, any Securityholder who
has been a bona fide holder of a Security for at least six months may, on behalf
of himself and all others similarly situated, petition any court of competent
jurisdiction for the removal of the Debenture Trustee and the appointment of a
successor trustee. Such court



                                       39
<PAGE>   47

may thereupon, after such notice, if any, as it may deem proper and prescribe,
remove the Debenture Trustee and appoint a successor trustee.

         (c) The holders of a majority in aggregate principal amount of the
Securities at the time outstanding may at any time remove the Debenture Trustee
and nominate a successor trustee, which shall be deemed appointed as successor
trustee unless within 10 days after written notification of such nomination the
Corporation objects thereto, or if no successor trustee shall have been so
appointed and shall have accepted appointment within 30 days after such removal,
in which case the Debenture Trustee so removed or any Securityholder, upon the
terms and conditions and otherwise as in subsection (a) of this Section 6.10
provided, may petition any court of competent jurisdiction for an appointment of
a successor trustee.

         (d) Any resignation or removal of the Debenture Trustee and appointment
of a successor trustee pursuant to any of the provisions of this Section 6.10
shall become effective upon acceptance of appointment by the successor trustee
as provided in Section 6.11.

         SECTION 6.10 ACCEPTANCE BY SUCCESSOR DEBENTURE TRUSTEE.

         Any successor trustee appointed as provided in Section 6.10 shall
execute, acknowledge and deliver to the Corporation and to its predecessor
trustee an instrument accepting such appointment hereunder, and thereupon the
resignation or removal of the retiring 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 Corporation or of the successor
trustee, the trustee ceasing to act shall, upon payment of all amounts then due
it pursuant to the provisions of Section 6.06, execute and deliver an instrument
transferring to such successor trustee all the rights and powers of the trustee
so ceasing to act and shall duly assign, transfer and deliver to such successor
trustee all property and money held by such retiring trustee thereunder. Upon
request of any such successor trustee, the Corporation 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 or funds held or collected
by such trustee to secure any amounts then due it pursuant to the provisions of
Section 6.06.

         No successor trustee shall accept appointment as provided in this
Section 6.11 unless at the time of such acceptance such successor trustee shall
be qualified under the provisions of Section 6.08 and eligible under the
provisions of Section 6.09.

         Upon acceptance of appointment by a successor trustee as provided in
this Section 6.11, the Corporation shall mail notice of the succession of such
trustee hereunder to the holders of Securities at their addresses as they shall
appear on the Security Register. If the Corporation fails to mail such notice
within 10 days after the acceptance of appointment by the successor trustee, the
successor trustee shall cause such notice to be mailed at the expense of the
Corporation.

         SECTION 6.11 SUCCESSION BY MERGER, ETC.



                                       40
<PAGE>   48

         Any Person into which the Debenture Trustee may be merged or converted
or with which it may be consolidated, or any Person resulting from any merger,
conversion or consolidation to which the Debenture Trustee shall be a party, or
any Person succeeding to all or substantially all of the corporate trust
business of the Debenture Trustee, shall be the successor of the Debenture
Trustee hereunder without the execution or filing of any paper or any further
act on the part of any of the parties hereto.

         In case any Securities shall have been authenticated but not delivered
at the time such successor to the Debenture Trustee shall succeed to the trusts
created by this Indenture, any such successor to the Debenture Trustee may adopt
the certificate of authentication of any predecessor trustee, and deliver such
Securities so authenticated; and in case at that time any of the Securities
shall not have been authenticated, any successor to the Debenture Trustee may
authenticate such Securities either in the name of any predecessor hereunder or
in the name of the successor trustee; and in all such cases such certificates
shall have the full force which the Securities or this Indenture elsewhere
provides that the certificate of the Debenture Trustee shall have; PROVIDED,
HOWEVER, that the right to adopt the certificate of authentication of any
predecessor Debenture Trustee or authenticate Securities in the name of any
predecessor Debenture Trustee shall apply only to its successor or successors by
merger, conversion or consolidation.

         SECTION 6.12 LIMITATION ON RIGHTS OF DEBENTURE TRUSTEE AS A CREDITOR.

         The Debenture Trustee shall comply with Section 311(a) of the Trust
Indenture Act, excluding any creditor relationship described in Section 311(b)
of the Trust Indenture Act. A Debenture Trustee who has resigned or been removed
shall be subject to Section 311(a) of the Trust Indenture Act to the extent
included therein.

         SECTION 6.13 AUTHENTICATING AGENTS.

         There may be one or more Authenticating Agents appointed by the
Debenture Trustee upon the request of the Corporation with power to act on the
Debenture Trustee's behalf and subject to the Debenture Trustee's direction in
the authentication and delivery of Securities issued upon exchange or transfer
thereof as fully to all intents and purposes as though any such Authenticating
Agent had been expressly authorized to authenticate and deliver Securities;
PROVIDED, HOWEVER, that the Debenture Trustee shall have no liability to the
Corporation for any acts or omissions of the Authenticating Agent with respect
to the authentication and delivery of Securities. Any such Authenticating Agent
shall at all times be a Person organized and doing business under the laws of
the United States or of any state or territory thereof or of the District of
Columbia authorized under such laws to act as Authenticating Agent, having a
combined capital and surplus of at least $5,000,000 and being subject to
supervision or examination by federal, state, territorial or District of
Columbia authority. If such Person publishes reports of condition at least
annually pursuant to law or the requirements of such authority, then for the
purposes of this Section 6.14 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 an Authenticating Agent
shall cease to be eligible in accordance with



                                       41
<PAGE>   49

the provisions of this Section, it shall resign immediately in the manner and
with the effect herein specified in this Section.

         Any Person into which any Authenticating Agent may be merged, converted
or with which it may be consolidated, or any Person resulting from any merger or
consolidation to which any Authenticating Agent shall be a party, or any Person
succeeding to the corporate trust business of any Authenticating Agent, shall be
the successor of such Authenticating Agent hereunder, if such successor Person
is otherwise eligible under this Section 6.14 without the execution or filing of
any paper or any further act on the part of the parties hereto or such
Authenticating Agent.

         Any Authenticating Agent may at any time resign by giving written
notice of resignation to the Debenture Trustee and to the Corporation. The
Debenture 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 Corporation. 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 6.14, the Debenture Trustee may, and upon the
request of the Corporation shall, promptly appoint a successor Authenticating
Agent eligible under this Section 6.14, shall give written notice of such
appointment to the Corporation and shall mail notice of such appointment to all
Securityholders as the names and addresses of such holders appear on the
Security Register. Any successor Authenticating Agent upon acceptance of its
appointment hereunder shall become vested with all rights, powers, duties and
responsibilities of its predecessor hereunder, with like effect as if originally
named as Authenticating Agent herein.

         The Corporation, as issuer of the Securities, agrees to pay to any
Authenticating Agent from time to time reasonable compensation for its services.
Any Authenticating Agent shall have no responsibility or liability for any
action taken by it as such in accordance with the directions of the Debenture
Trustee.

                                   ARTICLE VII
                         CONCERNING THE SECURITYHOLDERS

         SECTION 7.01 ACTION BY SECURITYHOLDERS.

         Whenever in this Indenture it is provided that the holders of a
specified percentage in aggregate principal amount of the Securities may take
any action (including the making of any 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 (including by way of
electronic transmission) or any number of instruments of similar tenor executed
by such Securityholders in person or by agent or proxy appointed in writing, or
(b) by the record of such holders of Securities voting in favor thereof at any
meeting of such Securityholders duly called and held in accordance with the
provisions of Article VIII, or (c) by a combination of such instrument or
instruments and any such record of such a meeting of such Securityholders.



                                       42
<PAGE>   50

         If the Corporation shall solicit from the Securityholders any request,
demand, authorization, direction, notice, consent, waiver or other action, the
Corporation may, at its option, as evidenced by an Officers' Certificate, fix in
advance a record date for the determination of Securityholders entitled to give
such request, demand, authorization, direction, notice, consent, waiver or other
action, but the Corporation shall have no obligation to do so. If such a record
date is fixed, such request, demand, authorization, direction, notice, consent,
waiver or other action may be given before or after the record date, but only
the Securityholders of record at the close of business on the record date shall
be deemed to be Securityholders for the purposes of determining whether
Securityholders of the requisite proportion of outstanding Securities have
authorized or agreed or consented to such request, demand, authorization,
direction, notice, consent, waiver or other action, and for that purpose the
outstanding Securities shall be computed as of the record date; PROVIDED,
HOWEVER, that no such authorization, agreement or consent by such
Securityholders on the record date shall be deemed effective unless it shall
become effective pursuant to the provisions of this Indenture not later than six
months after the record date.

         SECTION 7.02 PROOF OF EXECUTION BY SECURITYHOLDERS.

         Subject to the provisions of Sections 6.01, 6.02 and 8.05, proof of the
execution of any instrument by a Securityholder or his agent or proxy shall be
sufficient if made in accordance with such reasonable rules and regulations as
may be prescribed by the Debenture Trustee or in such manner as shall be
satisfactory to the Debenture Trustee. The ownership of Securities shall be
proven by the Security Register or by a certificate of the security registrar
for the Securities. The Debenture Trustee may require such additional proof of
any matter referred to in this Section 7.02 as it shall deem necessary.

         The record of any Securityholders' meeting shall be proven in the
manner provided in Section 8.06.

         SECTION 7.03 WHO ARE DEEMED ABSOLUTE OWNERS.

         Prior to due presentment for registration of transfer of any Security,
the Corporation, the Debenture Trustee, any Authenticating Agent, any paying
agent, any transfer agent and any security registrar for the Securities may deem
the person in whose name such Security shall be registered upon the Security
Register to be, and may treat him or her as, the absolute owner of such Security
(whether or not such Security shall be overdue) for the purpose of receiving
payment of or on account of the principal of and premium, if any, and (subject
to Section 2.06) interest on such Security and for all other purposes; and
neither the Corporation nor the Debenture Trustee nor any Authenticating Agent
nor any paying agent nor any transfer agent nor any security registrar for the
Securities shall be affected by any notice to the contrary. All such payments so
made to any holder for the time being or upon his or her order shall be valid
and, to the extent of the sum or sums so paid, effectual to satisfy and
discharge the liability for moneys payable upon any such Security.

         SECTION 7.04 SECURITIES OWNED BY CORPORATION DEEMED NOT OUTSTANDING.



                                       43
<PAGE>   51

         In determining whether the holders of the requisite aggregate principal
amount of Securities have concurred in any direction, consent or waiver under
this Indenture, Securities that are owned by the Corporation or any other
obligor on the Securities or by any Person directly or indirectly controlling or
controlled by or under direct or indirect common control with the Corporation or
any other obligor on the Securities shall be disregarded and deemed not to be
outstanding for the purpose of any such determination; PROVIDED, HOWEVER, that
for the purposes of determining whether the Debenture Trustee shall be protected
in relying on any such direction, consent or waiver, only Securities which a
Responsible Officer of the Debenture Trustee actually knows are so owned shall
be so disregarded. Securities so owned which have been pledged in good faith may
be regarded as outstanding for the purposes of this Section 7.04 if the pledgee
shall establish to the satisfaction of the Debenture Trustee the pledgee's right
to vote such Securities and that the pledgee is not the Corporation or any such
other obligor or Person directly or indirectly controlling or controlled by or
under direct or indirect common control with the Corporation or any such other
obligor. In the case of a dispute as to such right, any decision by the
Debenture Trustee taken upon the advice of counsel shall be full protection to
the Debenture Trustee.

         SECTION 7.05 REVOCATION OF CONSENTS; FUTURE HOLDERS BOUND.

         At any time prior to (but not after) the evidencing to the Debenture
Trustee, as provided in Section 7.01, of the taking of any action by the holders
of the percentage in aggregate principal amount of the Securities specified in
this Indenture in connection with such action, any holder of a Security (or any
Security issued in whole or in part in exchange or substitution therefor),
subject to Section 7.01, the serial number of which is shown by the evidence to
be included in the group of Securities the holders of which have consented to
such action, may, by filing written notice with the Debenture Trustee at its
principal office and upon proof of holding as provided in Section 7.02, revoke
such action so far as concerns such Security (or so far as concerns the
principal amount represented by any exchanged or substituted Security). Except
as aforesaid, any such action taken by the holder of any Security shall be
conclusive and binding upon such holder and upon all future holders and owners
of such Security, and of any Security issued in exchange or substitution
therefor, irrespective of whether or not any notation in regard thereto is made
upon such Security or any Security issued in exchange or substitution therefor.


                                  ARTICLE VIII
                           MEETINGS OF SECURITYHOLDERS

         SECTION 8.01 PURPOSES OF MEETINGS.

         A meeting of Securityholders may be called at any time and from time to
time pursuant to the provisions of this Article VIII for any of the following
purposes:

         (a)      to give any notice to the Corporation or to the Debenture
                  Trustee, or to give any directions to the Debenture Trustee,
                  or to consent to the waiving of any Default hereunder and its
                  consequences, or to take any other action authorized to be
                  taken by Securityholders pursuant to any of the provisions of
                  Article V;



                                       44
<PAGE>   52

         (b)      to remove the Debenture Trustee and nominate a successor
                  trustee pursuant to the provisions of Article VI;

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

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

         SECTION 8.02 CALL OF MEETINGS BY DEBENTURE TRUSTEE.

         The Debenture Trustee may at any time call a meeting of Securityholders
to take any action specified in Section 8.01, to be held at such time and at
such place in Wilmington, Delaware as the Debenture Trustee shall determine.
Notice of every meeting of the Securityholders, setting forth the time and the
place of such meeting and in general terms the action proposed to be taken at
such meeting, shall be mailed to holders of Securities at their addresses as
they shall appear on the Security Register. Such notice shall be mailed not less
than 20 nor more than 180 days prior to the date fixed for the meeting.

         SECTION 8.03 CALL OF MEETINGS BY CORPORATION OR SECURITYHOLDERS.

         In case at any time the Corporation, pursuant to a resolution of the
Board of Directors, or the holders of at least 20% in aggregate principal amount
of the Securities then outstanding, shall have requested the Debenture Trustee
to call a meeting of Securityholders, by written request setting forth in
reasonable detail the action proposed to be taken at the meeting, and the
Debenture Trustee shall not have mailed the notice of such meeting within 20
days after receipt of such request, then the Corporation or such Securityholders
may determine the time and the place in Bowling Green, Ohio for such meeting and
may call such meeting to take any action authorized in Section 8.01, by mailing
notice thereof as provided in Section 8.02.

         SECTION 8.04 QUALIFICATIONS FOR VOTING.

         To be entitled to vote at any meeting of Securityholders, a Person
shall be (a) a holder of one or more Securities or (b) a Person appointed by an
instrument in writing as proxy by a holder of one or more Securities. The only
Persons who shall be entitled to be present or to speak at any meeting of
Securityholders shall be the Persons entitled to vote at such meeting and their
counsel and any representatives of the Debenture Trustee and its counsel and any
representatives of the Corporation and its counsel.

         SECTION 8.05  REGULATIONS.

         Notwithstanding any other provisions of this Indenture, the Debenture
Trustee may make such reasonable regulations as it may deem advisable for any
meeting of Securityholders, in regard to proof of the holding of Securities and
of the appointment of proxies, and in regard to



                                       45
<PAGE>   53

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 Debenture Trustee shall, by an instrument in writing, appoint a
temporary chairman of the meeting, unless the meeting shall have been called by
the Corporation or by Securityholders as provided in Section 8.03, in which case
the Corporation or the Securityholders 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 majority vote of the
meeting.

         Subject to the provisions of Section 8.04, at any meeting each holder
of Securities or proxy therefor shall be entitled to one vote for each $1,000
principal amount of Securities held or represented by him or her; PROVIDED,
HOWEVER, that no vote shall be cast or counted at any meeting in respect of any
Security 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 Securities held by him or instruments in writing as
aforesaid duly designating him as the person to vote on behalf of other
Securityholders. Any meeting of Securityholders duly called pursuant to the
provisions of Section 8.02 or 8.03 may be adjourned from time to time by a
majority of those present, and the meeting may be held as so adjourned without
further notice.

         SECTION 8.06 VOTING.

         The vote upon any resolution submitted to any meeting of holders of
Securities shall be by written ballots on which shall be subscribed the
signatures of such holders or of their representatives by proxy and the serial
number or numbers of the Securities 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
triplicate of all votes cast at the meeting. A record in duplicate of the
proceedings of each meeting of Securityholders 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
provided in Section 8.02. The record shall show the serial numbers of the
Securities 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 Corporation and
the other to the Debenture Trustee to be preserved by the Debenture 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.
The holders of the Initial Securities and the Exchange Securities shall vote for
all purposes as a single class.


                                   ARTICLE IX
                                   AMENDMENTS



                                       46
<PAGE>   54

         SECTION 9.01 WITHOUT CONSENT OF SECURITYHOLDERS.

         The Corporation and the Debenture Trustee may from time to time and at
any time amend this Indenture, without the consent of the Securityholders for
one or more of the following purposes:

         (a)      to evidence the succession of another Person to the
                  Corporation, or successive successions, and the assumption by
                  the successor Person of the covenants, agreements and
                  obligations of the Corporation pursuant to Article X hereof;

         (b)      to add to the covenants of the Corporation such further
                  covenants, restrictions or conditions for the protection of
                  the Securityholders as the Board of Directors and the
                  Debenture Trustee shall consider to be for the protection of
                  the Securityholders, and to make the occurrence, or the
                  occurrence and continuance, of a default in any of such
                  additional covenants, restrictions or conditions a Default or
                  an Event of Default permitting the enforcement of all or any
                  of the remedies provided in this Indenture as herein set
                  forth; PROVIDED, HOWEVER, that in respect of any such
                  additional covenant, restriction or condition such amendment
                  may provide for a particular 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 Debenture Trustee upon such default;

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

         (d)      to cure any ambiguity or to correct or supplement any
                  provision contained herein or in any supplemental indenture
                  which 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, provided that any such
                  action shall not materially adversely affect the interests of
                  the holders of the Securities;

         (e)      to evidence and provide for the acceptance of appointment
                  hereunder by a successor trustee with respect to the
                  Securities;

         (f)      to make provision for transfer procedures, certification,
                  book-entry provisions, the form of restricted securities
                  legends, if any, to be placed on Securities, and all other
                  matters required pursuant to Section 2.07 or otherwise
                  necessary, desirable or appropriate in connection with the
                  issuance of Securities to holders of Capital Securities in the
                  event of a distribution of Securities by the Trust following a
                  Dissolution Event, provided that any such action shall not
                  materially adversely affect the interests of the holders of
                  the Securities;



                                       47
<PAGE>   55

         (g)      to qualify or maintain qualification of this Indenture under
                  the Trust Indenture Act; or

         (h)      to make any change that does not adversely affect the rights
                  of any Securityholder in any material respect.

         The Debenture Trustee is hereby authorized to join with the Corporation
in the execution of any supplemental indenture to effect such amendment, to make
any further appropriate agreements and stipulations which may be therein
contained and to accept the conveyance, transfer and assignment of any property
thereunder, but the Debenture Trustee shall not be obligated to, but may in its
discretion, enter into any such supplemental indenture which affects the
Debenture Trustee's own rights, duties or immunities under this Indenture or
otherwise.

         Any amendment to this Indenture authorized by the provisions of this
Section 9.01 may be executed by the Corporation and the Debenture Trustee
without the consent of the holders of any of the Securities at the time
outstanding, notwithstanding any of the provisions of Section 9.02.

         SECTION 9.02 WITH CONSENT OF SECURITYHOLDERS.

         With the consent (evidenced as provided in Section 7.01) of the holders
of a majority in aggregate principal amount of the Securities at the time
outstanding the Corporation, when authorized by a Board Resolution, and the
Debenture Trustee may from time to time and at any time amend this Indenture for
the purpose of adding any provisions to or changing in any manner or eliminating
any of the provisions of this Indenture or of modifying in any manner the rights
of the holders of the Securities; PROVIDED, HOWEVER, that no such amendment
shall, without the consent of the holders of each Security then outstanding and
affected thereby (i) change the Maturity Date of any Security, or reduce the
rate or extend the time of payment of interest thereon (except as contemplated
by Article XVI), or reduce the principal amount thereof, or change any
prepayment provisions, or make the principal thereof or any interest or premium
thereon payable in any coin or currency other than U.S. dollars, or impair or
affect the right of any Securityholder to institute suit for payment thereof or
(ii) reduce the aforesaid percentage of Securities, the holders of which are
required to consent to any such amendment to the Indenture; PROVIDED, HOWEVER,
that if the Securities are held by the Trust, such amendment shall not be
effective until the holders of a majority in liquidation amount of Trust
Securities shall have consented to such amendment; PROVIDED, FURTHER, that if
the consent of the holder of each outstanding Security is required, such
amendment shall not be effective until each holder of the Trust Securities shall
have consented to such amendment.

         Upon the request of the Corporation accompanied by a copy of a
resolution of the Board of Directors certified by its Secretary or Assistant
Secretary authorizing the execution of any supplemental indenture effecting such
amendment, and upon the filing with the Debenture Trustee of evidence of the
consent of Securityholders as aforesaid, the Debenture Trustee shall join with
the Corporation in the execution of such supplemental indenture unless such
supplemental indenture affects the Debenture Trustee's own rights, duties or
immunities under



                                       48
<PAGE>   56

this Indenture or otherwise, in which case the Debenture Trustee may in its
discretion, but shall not be obligated to, enter into such supplemental
indenture.

         Promptly after the execution by the Corporation and the Debenture
Trustee of any supplemental indenture pursuant to the provisions of this
Section, the Debenture Trustee shall transmit by mail, first class postage
prepaid, a notice, prepared by the Corporation, setting forth in general terms
the substance of such supplemental indenture, to the Securityholders as their
names and addresses appear upon the Security Register. Any failure of the
Debenture Trustee to mail such notice, or any defect therein, shall not,
however, in any way impair or affect the validity of any such supplemental
indenture.

         It shall not be necessary for the consent of the Securityholders under
this Section 9.02 to approve the particular form of any proposed supplemental
indenture, but it shall be sufficient if such consent shall approve the
substance thereof.

         SECTION 9.03 COMPLIANCE WITH TRUST INDENTURE ACT; EFFECT OF
SUPPLEMENTAL INDENTURES.

         Any supplemental indenture executed pursuant to the provisions of this
Article IX shall comply with the Trust Indenture Act. Upon the execution of any
supplemental indenture pursuant to the provisions of this Article IX, this
Indenture shall be and be deemed to be modified and amended in accordance
therewith and the respective rights, limitations of rights, obligations, duties
and immunities under this Indenture of the Debenture Trustee, the Corporation
and the holders of Securities 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 9.04 NOTATION ON SECURITIES.

         Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to the provisions of this Article IX may bear a
notation in form approved by the Debenture Trustee as to any matter provided for
in such supplemental indenture. If the Corporation or the Debenture Trustee
shall so determine, new Securities so modified as to conform, in the opinion of
the Debenture Trustee and the Board of Directors, to any modification of this
Indenture contained in any such supplemental indenture may be prepared and
executed by the Corporation, authenticated by the Debenture Trustee or the
Authenticating Agent and delivered in exchange for the Securities then
outstanding.

         SECTION 9.05 EVIDENCE OF COMPLIANCE OF SUPPLEMENTAL INDENTURE TO BE
FURNISHED TO DEBENTURE TRUSTEE.

         The Debenture Trustee, subject to the provisions of Sections 6.01 and
6.02, may receive 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 IX.


                                       49
<PAGE>   57

                                    ARTICLE X
           CONSOLIDATION, MERGER, SALE, CONVEYANCE, TRANSFER AND LEASE

         SECTION 10.01 CORPORATION MAY CONSOLIDATE, ETC., ON CERTAIN TERMS.

         Nothing contained in this Indenture or in any of the Securities shall
prevent any consolidation or merger of the Corporation with or into any other
Person (whether or not affiliated with the Corporation, as the case may be), or
successive consolidations or mergers in which the Corporation or its successor
or successors, as the case may be, shall be a party or parties, or shall prevent
any sale, conveyance, transfer or lease of the property of the Corporation, or
its successor or successors as the case may be, as an entirety, or substantially
as an entirety, to any other Person (whether or not affiliated with the
Corporation, or its successor or successors, as the case may be) authorized to
acquire and operate the same; PROVIDED, that (a) the Corporation is the
surviving Person, or the Person formed by or surviving any such consolidation or
merger (if other than the Corporation) or to which such sale, conveyance,
transfer or lease of property is made is a Person organized and existing under
the laws of the United States or any State thereof or the District of Columbia,
and (b) if the Corporation is not the surviving Person, 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 the Securities
according to their tenor and the due and punctual performance and observance of
all the covenants and conditions of this Indenture to be kept or performed by
the Corporation shall be expressly assumed by the surviving Person, by
supplemental indenture (which shall conform to the provisions of the Trust
Indenture Act as then in effect) satisfactory in form to the Debenture Trustee,
executed and delivered to the Debenture Trustee by the Person formed by such
consolidation, or into which the Corporation shall have been merged, or by the
Person which shall have acquired such property, as the case may be, and (c)
after giving effect to such consolidation, merger, sale, conveyance, transfer or
lease, no Default or Event of Default shall have occurred and be continuing.

         SECTION 10.02 SUCCESSOR PERSON TO BE SUBSTITUTED FOR CORPORATION.

         In case of any such consolidation, merger, sale, conveyance, transfer
or lease, and upon the assumption by the successor corporation, by supplemental
indenture, executed and delivered to the Debenture Trustee and satisfactory in
form to the Debenture Trustee, of the obligation of due and punctual payment of
the principal of (and premium, if any) and interest on all of the Securities and
the due and punctual performance and observance of all of the covenants and
conditions of this Indenture to be performed or observed by the Corporation,
such successor Person shall succeed to and be substituted for the Corporation,
with the same effect as if it had been named herein as a party hereto, and the
Corporation thereupon shall be relieved of any further liability or obligation
hereunder or upon the Securities. Such successor Person thereupon may cause to
be signed, and may issue either in its own name or in the name of the
Corporation, any or all of the Securities issuable hereunder which theretofore
shall not have been signed by the Corporation and delivered to the Debenture
Trustee or the Authenticating Agent; and, upon the order of such successor
Person instead of the Corporation and subject to all the terms, conditions and
limitations in this Indenture prescribed, the Debenture Trustee or the




                                       50
<PAGE>   58

Authenticating Agent shall authenticate and deliver any Securities which
previously shall have been signed and delivered by any Officer of the
Corporation to the Debenture Trustee or the Authenticating Agent for
authentication, and any Securities which such successor Person thereafter shall
cause to be signed and delivered to the Debenture Trustee or the Authenticating
Agent for that purpose. All the Securities so issued shall in all respects have
the same legal rank and benefit under this Indenture as the Securities
theretofore or thereafter issued in accordance with the terms of this Indenture
as though all of such Securities had been issued at the date of the execution
hereof.

         SECTION 10.03 OPINION OF COUNSEL TO BE GIVEN DEBENTURE TRUSTEE.

         The Debenture Trustee, subject to the provisions of Sections 6.01 and
6.02, may receive an Opinion of Counsel as conclusive evidence that any
consolidation, merger, sale, conveyance, transfer or lease, and any assumption,
permitted or required by the terms of this Article X complies with the
provisions of this Article X.


                                   ARTICLE XI
                     SATISFACTION AND DISCHARGE OF INDENTURE

         SECTION 11.01 DISCHARGE OF INDENTURE.

         When (a) the Corporation shall deliver to the Debenture Trustee for
cancellation all Securities theretofore authenticated (other than any Securities
which shall have been destroyed, lost or stolen and which shall have been
replaced as provided in Section 2.08) and not theretofore canceled, or (b) all
the Securities not theretofore canceled or delivered to the Debenture 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 prepayment within
one year under arrangements satisfactory to the Debenture Trustee for the giving
of notice of prepayment, and the Corporation shall deposit with the Debenture
Trustee, in trust, funds sufficient to pay on the Maturity Date or upon
prepayment all of the Securities (other than any Securities which shall have
been destroyed, lost or stolen and which shall have been replaced as provided in
Section 2.08) not theretofore canceled or delivered to the Debenture Trustee for
cancellation, including principal (and premium, if any) and interest (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
due or to become due to the Maturity Date or prepayment date, as the case may
be, but excluding, however, the amount of any moneys for the payment of
principal of (or premium, if any) or interest (including Compounded Interest and
Additional Sums, if any) or Liquidated Damages, if any, on the Securities (1)
theretofore repaid to the Corporation in accordance with the provisions of
Section 11.04, or (2) paid to any State or to the District of Columbia pursuant
to its unclaimed property or similar laws, and if, in either case the
Corporation shall also pay or cause to be paid all other sums payable hereunder
by the Corporation, then this Indenture shall cease to be of further effect
except for the provisions of Sections 2.02, 2.07, 2.08, 3.01, 3.02, 3.04, 6.06,
6.10 and 11.04 hereof, which shall survive until such Securities shall mature
and be paid. Thereafter, Sections 6.06, 6.10 and 11.04 shall survive, and the
Debenture Trustee, on demand of the Corporation accompanied by any Officers'
Certificate and an Opinion of Counsel and at the cost and expense of the
Corporation, shall



                                       51
<PAGE>   59

execute proper instruments acknowledging satisfaction of and discharging this
Indenture; the Corporation, however, hereby agrees to reimburse the Debenture
Trustee for any costs or expenses thereafter reasonably and properly incurred by
the Debenture Trustee in connection with this Indenture or the Securities.

         SECTION 11.02 DEPOSITED MONEYS AND U.S. GOVERNMENT OBLIGATIONS TO BE
HELD IN TRUST BY DEBENTURE TRUSTEE.

         Subject to the provisions of Section 11.04, all moneys and U.S.
Government Obligations deposited with the Debenture Trustee pursuant to Sections
11.01 or 11.05 shall be held in trust and applied by it to the payment, either
directly or through any paying agent (including the Corporation if acting as its
own paying agent), to the holders of the particular Securities for the payment
of which such moneys or U.S. Government Obligations have been deposited with the
Debenture Trustee, of all sums due and to become due thereon for principal,
premium, if any, and interest.

         The Corporation shall pay and indemnify the Debenture Trustee against
any tax, fee or other charge imposed on or assessed against the U.S.
Governmental Obligations deposited pursuant to Section 11.05 or the principal
and interest received in respect thereof other than any such tax, fee or other
charge which by law is for the account of the holders of outstanding Securities.

         SECTION 11.03 PAYING AGENT TO REPAY MONEYS HELD.

         Upon the satisfaction and discharge of this Indenture all moneys then
held by any paying agent of the Securities (other than the Debenture Trustee)
shall, upon written demand of the Corporation, be repaid to it or paid to the
Debenture Trustee, and thereupon such paying agent shall be released from all
further liability with respect to such moneys.

         SECTION 11.04 RETURN OF UNCLAIMED MONEYS.

         Any moneys deposited with or paid to the Debenture Trustee or any
paying agent for payment of the principal of (or premium, if any) or interest
(including Compounded Interest and Additional Sums, if any) or Liquidated
Damages, if any, on Securities and not applied but remaining unclaimed by the
holders of Securities for two years after the date upon which the principal of
(or premium, if any) or interest (including Compounded Interest and Additional
Sums, if any) or Liquidated Damages, if any, on such Securities, as the case may
be, shall have become due and payable, shall be repaid to the Corporation by the
Debenture Trustee or such paying agent; and the holder of any of the Securities
shall thereafter look only to the Corporation for any payment which such holder
may be entitled to collect and all liability of the Debenture Trustee or such
paying agent with respect to such moneys shall thereupon cease.

         SECTION 11.05 DEFEASANCE UPON DEPOSIT OF MONEYS OR U.S. GOVERNMENT
OBLIGATIONS.



                                       52
<PAGE>   60

         The Corporation shall be deemed to have been Discharged (as defined
below) from its obligations with respect to the Securities on the 91st day after
the applicable conditions set forth below have been satisfied:

         (a)      the Corporation shall have deposited or caused to be deposited
                  irrevocably with the Debenture Trustee or the Defeasance Agent
                  (as defined below) as trust funds in trust, specifically
                  pledged as security for, and dedicated solely to, the benefit
                  of the holders of the Securities (i) money in an amount, or
                  (ii) U.S. Government Obligations which through the payment of
                  interest and principal in respect thereof in accordance with
                  their terms will provide, not later than one day before the
                  due date of any payment, money in an amount, or (iii) a
                  combination of (i) and (ii), sufficient, in the opinion (with
                  respect to (ii) and (iii)) of a nationally recognized firm of
                  independent public accountants expressed in a written
                  certification thereof delivered to the Debenture Trustee and
                  the Defeasance Agent, if any, to pay and discharge each
                  installment of principal of and interest on and premium, if
                  any, and Liquidated Damages, if any, in respect of the
                  outstanding Securities on the dates such installments of
                  principal and interest (and premium, if any) and Liquidated
                  Damages, if any, are due;

         (b)      if the Securities are then listed on any national securities
                  exchange, the Corporation shall have delivered to the
                  Debenture Trustee and the Defeasance Agent, if any, an Opinion
                  of Counsel to the effect that the exercise of the option under
                  this Section 11.05 would not cause such Securities to be
                  delisted from such exchange;

         (c)      no Default or Event of Default with respect to the Securities
                  shall have occurred and be continuing on the date of such
                  deposit; and

         (d)      the Corporation shall have delivered to the Debenture Trustee
                  and the Defeasance Agent, if any, an Opinion of Counsel to the
                  effect that holders of the Securities will not recognize
                  income, gain or loss for United States federal income tax
                  purposes as a result of the exercise of the option under this
                  Section 11.05 and will be subject to United States federal
                  income tax on the same amount and in the same manner and at
                  the same times as would have been the case if such option had
                  not been exercised.

         "Discharged" means that the Corporation shall be deemed to have paid
and discharged the entire indebtedness represented by, and obligations under,
the Securities and to have satisfied all the obligations under this Indenture
relating to the Securities (and the Debenture Trustee, at the expense of the
Corporation, shall execute proper instruments acknowledging the same), except
(1) the rights of holders of Securities to receive, from the trust fund
described in clause (a) above, payment of the principal of and the interest and
premium, if any, and Liquidated Damages, if any, on the Securities when such
payments are due; (2) the Corporation's obligations with respect to the
Securities under Sections 2.07, 2.08, 5.02 and 11.04; and (3) the rights,
powers, trusts, duties and immunities of the Debenture Trustee hereunder.



                                       53
<PAGE>   61

         "Defeasance Agent" means another financial institution which is
eligible to act as Debenture Trustee hereunder and which assumes all of the
obligations of the Debenture Trustee necessary to enable the Debenture Trustee
to act hereunder. In the event such a Defeasance Agent is appointed pursuant to
this Section, the following conditions shall apply:

         (1)      the Debenture Trustee shall have approval rights over the
                  document appointing such Defeasance Agent and the document
                  setting forth such Defeasance Agent's rights and
                  responsibilities; and

         (2)      the Defeasance Agent shall provide verification to the
                  Debenture Trustee acknowledging receipt of sufficient money
                  and/or U.S. Government Obligations to meet the applicable
                  conditions set forth in this Section 11.05.


                                   ARTICLE XII
                    IMMUNITY OF INCORPORATORS, STOCKHOLDERS,
                             OFFICERS AND DIRECTORS

         SECTION 12.01 INDENTURE AND SECURITIES SOLELY CORPORATE OBLIGATIONS.

         No recourse for the payment of the principal of or premium, if any, or
interest (including Compounded Interest and Additional Sums, if any) or
Liquidated Damages, if any, on any Security, or for any claim based thereon or
otherwise in respect thereof, and no recourse under or upon any obligation,
covenant or agreement of the Corporation in this Indenture, or in any Security,
or because of the creation of any indebtedness represented thereby, shall be had
against any incorporator, stockholder, employee, officer or director, as such,
past, present or future, of the Corporation or of any successor Person to the
Corporation, either directly or through the Corporation or any successor Person
to the 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 issuance of the Securities.


                                  ARTICLE XIII
                            MISCELLANEOUS PROVISIONS

         SECTION 13.01 SUCCESSORS.

         All of the covenants, stipulations, promises and agreements of the
Corporation contained in this Indenture shall also bind the Corporation's
successors and assigns whether so expressed or not.

         SECTION 13.02 OFFICIAL ACTS BY SUCCESSOR CORPORATION.

         Any act or proceeding that, by any provision of this Indenture, is
authorized or required to be done or performed by any board, committee or
officer of the Corporation shall and may be



                                       54
<PAGE>   62

done and performed with like force and effect by the like board, committee or
officer of any corporation that shall at the time be the lawful sole successor
of the Corporation.

         SECTION 13.03 SURRENDER OF CORPORATION POWERS.

         The Corporation by instrument in writing executed by authority of 2/3
(two-thirds) of its Board of Directors and delivered to the Debenture Trustee
may surrender any of the powers reserved to the Corporation hereunder, and
thereupon such power so surrendered shall terminate both as to the Corporation,
as the case may be, and as to any successor Person.

         SECTION 13.04 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 Debenture Trustee or by the
holders of Securities on the Corporation may be given or served by being
deposited postage prepaid by first class mail, registered or certified mail,
overnight courier service or conformed telecopy addressed (until another address
is filed by the Corporation with the Debenture Trustee for the purpose) to Sky
Financial Group, Inc. at 221 South Church Street, Bowling Green, Ohio 43402
Attention: W. Granger, Souder, Esq., General Counsel. Any notice, direction,
request or demand by any Securityholder to or upon the Debenture Trustee shall
be deemed to have been sufficiently given or made, for all purposes, if given or
made in writing at the office of Wilmington Trust Company at Rodney Square
North, 1100 North Market Street, Wilmington, Delaware 19890-0001, Attention:
Corporate Trust Administration (unless another address is provided by the
Debenture Trustee to the Corporation for such purpose). Any notice or
communication to a Securityholder shall be mailed by first class mail to his or
her address shown on the Security Register kept by the security registrar for
the Securities. Notices required to be given to the Debenture Trustee or the
Authenticating Agent shall be in writing, personally delivered or mailed
first-class postage prepaid to each of the foregoing, or at such other address
as shall be designated by written notice to the other parties.

         SECTION 13.05 GOVERNING LAW.

         This Indenture and each Security shall be deemed to be a contract made
under the laws of the State of New York, and for all purposes shall be governed
by and construed in accordance with the laws of said State without regard to
conflict of law principles thereof.

         SECTION 13.06 EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT.

         Upon any application or demand by the Corporation to the Debenture
Trustee to take any action under any of the provisions of this Indenture, the
Corporation shall furnish to the Debenture Trustee an Officers' Certificate
stating that in the opinion of the signers all conditions precedent, if any,
provided for in this Indenture relating to the proposed action have been
complied with and an Opinion of Counsel stating that, in the opinion of such
counsel, all such conditions precedent have been complied with.



                                       55
<PAGE>   63

         Each certificate or opinion provided for in this Indenture and
delivered to the Debenture Trustee with respect to compliance with a condition
or covenant provided for in this Indenture (except certificates delivered
pursuant to Section 3.05) shall include (1) a statement that the Person making
such certificate or opinion has read such covenant or condition; (2) a brief
statement as to the nature and scope of the examination or investigation upon
which the statements or opinions contained in such certificate or opinion are
based; (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 13.07 BUSINESS DAYS.

         In any case where the date of payment of principal of (or premium, if
any) or interest on the Securities is not a Business Day, the payment of such
principal of (or premium, if any) or interest on the Securities will not be made
on such date but will be made on the next succeeding Business Day, except if
such Business Day is in the next succeeding calendar year, such payment will be
made on the immediately preceding Business Day, with the same force and effect
as if made on the original date of payment, and no interest shall accrue for the
period from and after such date.

         SECTION 13.08 TRUST INDENTURE ACT TO CONTROL.

         If and to the extent that any provision of this Indenture limits,
qualifies or conflicts with the duties imposed by Sections 310 to 318,
inclusive, of the Trust Indenture Act, such imposed duties shall control.

         SECTION 13.09 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 13.10 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 13.11 SEPARABILITY.

         In case any one or more of the provisions contained in this Indenture
or in the Securities shall for any reason be held to be invalid, illegal or
unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provisions of this Indenture or of the Securities,
but this Indenture and the Securities shall be construed as if such invalid or
illegal or unenforceable provision had never been contained herein or therein.



                                       56
<PAGE>   64

         SECTION 13.12 ASSIGNMENT.

         The Corporation will have the right at all times to assign any of its
respective rights or obligations under this Indenture to a direct or indirect
wholly owned Subsidiary of the Corporation, provided that, in the event of any
such assignment, the Corporation will remain liable for all such obligations.
Subject to the foregoing, this Indenture is binding upon and inures to the
benefit of the parties thereto and their respective successors and assigns. This
Indenture may not otherwise be assigned by the parties thereto.

         SECTION 13.13 ACKNOWLEDGMENT OF RIGHTS.

         The Corporation acknowledges that, with respect to any Securities held
by the Trust or a trustee of such Trust, if the Property Trustee of such Trust
fails to enforce its rights under this Indenture as the holder of the Securities
held as the assets of the Trust, any holder of Capital Securities may institute
legal proceedings, subject to Section 5.09, directly against the Corporation to
enforce such Property Trustee's rights under this Indenture without first
instituting any legal proceedings against such Property Trustee or any other
person or entity. Notwithstanding the foregoing, if an Event of Default has
occurred and is continuing and such event is attributable to the failure of the
Corporation to pay principal of (or premium, if any) or interest on the
Securities when due, the Corporation acknowledges that a holder of Capital
Securities may directly institute a proceeding for enforcement of payment to
such holder of the principal of (or premium, if any) or interest on the
Securities having an aggregate principal amount equal to the aggregate
liquidation amount of the Capital Securities of such holder on or after the
respective due date specified in the Securities.


                                   ARTICLE XIV
                            PREPAYMENT OF SECURITIES

         SECTION 14.01 SPECIAL EVENT PREPAYMENT.

         If, prior to the Initial Optional Redemption Date, a Special Event has
occurred and is continuing, then notwithstanding Section 14.02(a) but subject to
Section 14.02(c), the Corporation shall have the right, at any time within 90
days following the occurrence of such Special Event, upon (i) not less than 45
days' written notice to the Debenture Trustee and (ii) not less than 30 days nor
more than 60 days' written notice to the Securityholders, to prepay the
Securities, in whole (but not in part), at the Special Event Prepayment Price.
Following a Special Event, the Corporation shall take such action as is
necessary to promptly determine the Special Event Prepayment Price, including,
without limitation, the appointment of a Quotation Agent. The Special Event
Prepayment Price shall be paid prior to 12:00 noon, New York City time, on the
date of such prepayment or such earlier time as the Corporation determines,
provided that the Corporation shall deposit with the Debenture Trustee an amount
sufficient to pay the Special Event Prepayment Price by 10:00 a.m., New York
City time, on the date such Special Event Prepayment Price is to be paid.

         SECTION 14.02 OPTIONAL PREPAYMENT BY CORPORATION.



                                       57
<PAGE>   65

         (a) Subject to Sections 14.02(b) and (c), the Corporation shall have
the right to prepay the Securities, in whole or in part, at any time on or after
the Initial Optional Redemption Date, upon (i) not more than 45 days' written
notice to the Debenture Trustee and (ii) not less than 30 days and not more than
60 days' written notice to the Securityholders, at the prepayment prices set
forth below plus, in each case, accrued and unpaid interest thereon (including
Compounded Interest and Additional Sums, if any) to the applicable date of
prepayment (the "Optional Prepayment Price"), if prepaid during the 12-month
period beginning May 1 of the years indicated below.

               Year                            Percentage of Principal
               ----                            -----------------------

               2010                                    104.670%
               2011                                    104.203%
               2012                                    103.736%
               2013                                    103.269%
               2014                                    102.802%
               2015                                    102.335%
               2016                                    101.868%
               2017                                    101.401%
               2018                                    100.934%
               2019                                    100.467%
               2020 and thereafter                     100.000%


         If the Securities are only partially prepaid pursuant to this Section
14.02, the Securities to be prepaid shall be selected on a pro rata basis not
more than 60 days prior to the date fixed for prepayment from the outstanding
Securities not previously called for prepayment; PROVIDED, HOWEVER, that with
respect to Securityholders that would be required to hold Securities with an
aggregate principal amount of less than $100,000 but more than an aggregate
principal amount of zero as a result of such pro rata prepayment, the
Corporation shall prepay Securities of each such Securityholder so that after
such prepayment such Securityholder shall hold Securities either with an
aggregate principal amount of at least $100,000 or such Securityholder no longer
holds any Securities, and shall use such method (including, without limitation,
by lot) as the Corporation shall deem fair and appropriate; PROVIDED, FURTHER,
that any such proration may be made on the basis of the aggregate principal
amount of Securities held by each Securityholder and may be made by making such
adjustments as the Corporation deems fair and appropriate in order that only
Securities in denominations of $1,000 or integral multiples thereof shall be
prepaid. The Optional Prepayment Price shall be paid prior to 12:00 noon New
York City time, on the date of such prepayment or at such earlier time as the
Corporation determines, PROVIDED that the Corporation shall deposit with the
Debenture Trustee an amount sufficient to pay the Optional Prepayment Price by
10:00 a.m., New York City time, on the date such Optional Prepayment Price is to
be paid.

         (b) Notwithstanding the first sentence of Section 14.02(a), upon the
entry of an order for dissolution of the Trust by a court of competent
jurisdiction, the Securities thereafter will be



                                       58
<PAGE>   66

subject to optional prepayment, in whole only, but not in part, on or after the
Initial Optional Redemption Date, at the applicable Optional Prepayment Price
and otherwise in accordance with this Article XIV.

         (c) Any prepayment of Securities pursuant to Section 14.01 or Section
14.02 shall be subject to the Corporation obtaining any and all required
regulatory approvals.

         SECTION 14.03 NO SINKING FUND.

         The Securities are not entitled to the benefit of any sinking fund.

         SECTION 14.04 NOTICE OF PREPAYMENT; SELECTION OF SECURITIES.

         In case the Corporation shall desire to exercise the right to prepay
all, or, as the case may be, any part of the Securities in accordance with their
terms, it shall fix a date for prepayment and shall mail a notice of such
prepayment at least 30 and not more than 60 days' prior to the date fixed for
prepayment to the holders of Securities to be so prepaid as a whole or in part
at their last addresses as the same appear on the Security Register. 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 Security designated for
prepayment as a whole or in part shall not affect the validity of the
proceedings for the prepayment of any other Security.

         Each such notice of prepayment shall specify the CUSIP number of the
Securities to be prepaid, the date fixed for prepayment, the Prepayment Price at
which the Securities are to be prepaid (or the method by which such Prepayment
Price is to be calculated), the place or places of payment where payment will be
made upon presentation and surrender of the Securities, that interest accrued to
the date fixed for prepayment will be paid as specified in said notice, and that
on and after said date interest thereon or on the portions thereof to be prepaid
will cease to accrue. If less than all the Securities are to be prepaid, the
notice of prepayment shall specify the numbers of the Securities to be prepaid.
In case any Security is to be prepaid in part only, the notice of prepayment
shall state the portion of the principal amount thereof to be prepaid and shall
state that on and after the date fixed for prepayment, upon surrender of such
Security, a new Security or Securities in principal amount equal to the portion
thereof that has not been prepaid will be issued.

         By 10:00 a.m., New York City time, on the prepayment date specified in
the notice of prepayment given as provided in this Section, the Corporation will
deposit with the Debenture Trustee or with one or more paying agents an amount
of money sufficient to prepay on the prepayment date all the Securities so
called for prepayment at the Prepayment Price.

         SECTION 14.05 PAYMENT OF SECURITIES CALLED FOR PREPAYMENT.

         If notice of prepayment has been given as provided in Section 14.04,
the Securities or portions of Securities with respect to which such notice has
been given shall become due and



                                       59
<PAGE>   67

payable on the date and at the place or places stated in such notice at the
Prepayment Price (subject to the rights of holders of Securities at the close of
business on a regular record date in respect of an Interest Payment Date
occurring on or prior to the prepayment date) and on and after said date (unless
the Corporation shall default in the payment of such Securities at the
Prepayment Price) interest (including Compounded Interest and Additional Sums,
if any) and Liquidated Damages, if any, on the Securities or portions of
Securities so called for prepayment shall cease to accrue. On presentation and
surrender of such Securities at a place of payment specified in said notice, the
said Securities or the specified portions thereof shall be paid and prepaid by
the Corporation at the applicable Prepayment Price, (subject to the rights of
holders of Securities on the close of business on a regular record date in
respect of an Interest Payment Date occurring on or prior to the prepayment
date).

         Upon presentation of any Security prepaid in part only, the Corporation
shall execute and the Debenture Trustee shall authenticate and make available
for delivery to the holder thereof, at the expense of the Corporation, a new
Security or Securities of authorized denominations, in principal amount equal to
the portion of the Security so presented that has not been prepaid.


                                   ARTICLE XV
                           SUBORDINATION OF SECURITIES

         SECTION 15.01 AGREEMENT TO SUBORDINATE

         The Corporation covenants and agrees, and each holder of Securities
issued hereunder likewise covenants and agrees, that the Securities shall be
issued subject to the provisions of this Article XV; and each holder of a
Security, whether upon original issue or upon transfer or assignment thereof,
accepts and agrees to be bound by such provisions.

         The payment by the Corporation of the principal of, premium, if any,
and interest (including Compounded Interest and Additional Sums, if any) and
Liquidated Damages, if any, on all Securities issued hereunder shall, to the
extent and in the manner hereinafter set forth, be subordinated and subject in
right of payment to the prior payment in full of all Allocable Amounts then due
and payable in respect of Senior Indebtedness, whether outstanding at the date
of this Indenture or thereafter incurred.

         No provision of this Article XV shall prevent the occurrence of any
Default or Event of Default hereunder.

         SECTION 15.02 DEFAULT ON SENIOR INDEBTEDNESS.

         In the event and during the continuation of any default by the
Corporation in the payment of principal, premium, interest or any other payment
due on any Senior Indebtedness, or in the event that the maturity of any Senior
Indebtedness has been accelerated because of a default and such acceleration has
not been rescinded or canceled, then, in either case, no payment shall be made
by the Corporation with respect to the principal (including prepayment payments)
of (or premium, if any) or interest on the Securities (including Compounded
Interest and Additional



                                       60
<PAGE>   68

Sums, if any, and Liquidated Damages, if any, or any other amounts which may be
due on the Securities pursuant to the terms hereof or thereof).

         In the event of the acceleration of the maturity of the Securities,
then no payment shall be made by the Corporation with respect to the principal
(including prepayment payments) of (or premium, if any) or interest on the
Securities (including Compounded Interest and Additional Sums, if any, and
Liquidated Damages, if any, or any other amounts which may be due on the
Securities pursuant to the terms hereof or thereof) until the holders of all
Senior Indebtedness outstanding at the time of such acceleration shall receive
payment, in full, of all Allocable Amounts due on or in respect of such Senior
Indebtedness (including any amounts due upon acceleration).

         In the event that, notwithstanding the foregoing, any payment is
received by the Debenture Trustee, or any Securityholder, when such payment is
prohibited by the preceding paragraphs of this Section 15.02, such payment shall
be held in trust for the benefit of, and shall be paid over or delivered by the
Debenture Trustee (if the notice requested by Section 15.06 has been received by
the Debenture Trustee) or by any Securityholder, to the holders of Senior
Indebtedness or their respective representatives, or to the trustee or trustees
under any indenture pursuant to which any of such Senior Indebtedness may have
been issued, as their respective interests may appear, but only to the extent of
the Allocable Amounts in respect of such Senior Indebtedness and to the extent
that the holders of the Senior Indebtedness (or their representative or
representatives or a trustee) notify the Debenture Trustee in writing within 90
days of such payment of the Allocable Amounts then due and owing on such Senior
Indebtedness, and only the Allocable Amounts specified in such notice to the
Debenture Trustee shall be paid to the holders of such Senior Indebtedness.

         SECTION 15.03 LIQUIDATION; DISSOLUTION; BANKRUPTCY.

         Upon any payment by the Corporation or distribution of assets of the
Corporation of any kind or character, whether in cash, property or securities,
to creditors upon any dissolution, winding-up, liquidation or reorganization of
the Corporation, whether voluntary or involuntary or in bankruptcy, insolvency,
receivership or other proceedings, the holders of all Senior Indebtedness of the
Corporation will first be entitled to receive payment in full of Allocable
Amounts due on or in respect of such Senior Indebtedness, before any payment is
made by the Corporation on account of the principal of (or premium, if any) or
interest on the Securities (including Compounded Interest and Additional Sums
(if any) and Liquidated Damages, if any, or any other amounts which may be due
on the Securities pursuant to the terms hereof or thereof); and upon any such
dissolution, winding-up, liquidation or reorganization, any payment by the
Corporation, or distribution of assets of the Corporation of any kind or
character, whether in cash, property or securities, which the Securityholders or
the Debenture Trustee would be entitled to receive from the Corporation, except
for the provisions of this Article XV, shall be paid by the Corporation or by
any receiver, trustee in bankruptcy, liquidating trustee, agent or other Person
making such payment or distribution, or by the Securityholders or by the
Debenture Trustee under the Indenture if received by them or it, directly to the
holders of Senior Indebtedness of the Corporation (pro rata to such holders on
the basis of the respective Allocable Amounts of Senior Indebtedness held by
such holders, as calculated by the



                                       61
<PAGE>   69

Corporation) or their representative or representatives, or to the trustee or
trustees under any indenture pursuant to which any instruments evidencing such
Senior Indebtedness may have been issued, as their respective interests may
appear, to the extent necessary to pay all such Allocable Amounts of Senior
Indebtedness in full, in money or moneys worth, after giving effect to any
concurrent payment or distribution to or for the holders of such Senior
Indebtedness, before any payment or distribution is made to the Securityholders
or to the Debenture Trustee.

         In the event that, notwithstanding the foregoing, any payment or
distribution of assets of the Corporation of any kind or character prohibited by
the foregoing, whether in cash, property or securities, shall be received by the
Debenture Trustee, or any Securityholder, before the Allocable Amounts of all
Senior Indebtedness is paid in full, or provision is made for such payment in
money in accordance with its terms, such payment or distribution shall be held
in trust for the benefit of and shall be paid over or delivered by the Debenture
Trustee (if the Notice requested by Section 15.06 has been received by the
Debenture Trustee) or by any Securityholder, to the holders of such Senior
Indebtedness or their representative or representatives, or to the trustee or
trustees under any indenture pursuant to which any instruments evidencing such
Senior Indebtedness may have been issued, as their respective interests may
appear, as calculated by the Corporation, for application to the payment of all
Allocable Amounts of Senior Indebtedness remaining unpaid to the extent
necessary to pay all Allocable Amounts due on or in respect of such Senior
Indebtedness in full in money in accordance with its terms, after giving effect
to any concurrent payment or distribution to or for the benefit of the holders
of such Senior Indebtedness.

         For purposes of this Article XV, the words "cash, property or
securities" shall not be deemed to include shares of stock of the Corporation as
reorganized or readjusted, or securities of the Corporation or any other
corporation provided for by a plan of reorganization or readjustment, the
payment of which is subordinated at least to the extent provided in this Article
XV with respect to the Securities to the payment of Senior Indebtedness that may
at the time be outstanding, PROVIDED that (i) such Senior Indebtedness is
assumed by the new corporation, if any, resulting from any such reorganization
or readjustment, and (ii) the rights of the holders of such Senior Indebtedness
are not, without the consent of such holders, altered by such reorganization or
readjustment. The consolidation of the Corporation with, or the merger of the
Corporation into, another Person or the liquidation or dissolution of the
Corporation following the sale, conveyance, transfer or lease of its property as
an entirety, or substantially as an entirety, to another Person upon the terms
and conditions provided for in Article X of this Indenture shall not be deemed a
dissolution, winding-up, liquidation or reorganization for the purposes of this
Section 15.03 if such other Person shall, as a part of such consolidation,
merger, sale, conveyance, transfer or lease, comply with the conditions stated
in Article X of this Indenture. Nothing in Section 15.02 or in this Section
15.03 shall apply to claims of, or payments to, the Debenture Trustee under or
pursuant to Section 6.06 of this Indenture.

         SECTION 15.04 SUBROGATION.

         Subject to the payment in full of all Allocable Amounts of Senior
Indebtedness, the rights of the Securityholders shall be subrogated to the
rights of the holders of such Senior Indebtedness to receive payments or
distributions of cash, property or securities of the Corporation, as the case
may be, applicable to such Senior Indebtedness until the principal of



                                       62
<PAGE>   70

(and premium, if any) and interest on the Securities shall be paid in full; and,
for the purposes of such subrogation, no payments or distributions to the
holders of such Senior Indebtedness of any cash, property or securities to which
the Securityholders or the Debenture Trustee would be entitled except for the
provisions of this Article XV, and no payment over pursuant to the provisions of
this Article XV to or for the benefit of the holders of such Senior Indebtedness
by Securityholders or the Debenture Trustee, shall, as between the Corporation,
its creditors other than holders of Senior Indebtedness of the Corporation, and
the holders of the Securities, be deemed to be a payment by the Corporation to
or on account of such Senior Indebtedness. It is understood that the provisions
of this Article XV are and are intended solely for the purposes of defining the
relative rights of the holders of the Securities, on the one hand, and the
holders of such Senior Indebtedness on the other hand.

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

         SECTION 15.05 DEBENTURE TRUSTEE TO EFFECTUATE SUBORDINATION.

         Each Securityholder, by such Securityholder's acceptance thereof,
authorizes and directs the Debenture Trustee on such Securityholder's behalf to
take such action (as the Debenture Trustee, in its discretion, deems necessary
or appropriate, upon instruction or otherwise) to effectuate the subordination
provided in this Article XV and appoints the Debenture Trustee such
Securityholder's attorney-in-fact for any and all such purposes.

         SECTION 15.06 NOTICE BY THE CORPORATION.

         The Corporation shall give prompt written notice to a Responsible
Officer of the Debenture Trustee of any fact known to the Corporation that would
prohibit the making of any payment of monies to or by the Debenture Trustee in
respect of the Securities pursuant to the provisions of this Article XV.
Notwithstanding the provisions of this Article XV or any other provision of this
Indenture, the Debenture Trustee shall not be charged with knowledge of the
existence of any facts that would prohibit the making of any payment of monies
to or by the Debenture Trustee in respect of the Securities pursuant to the
provisions of this Article XV, unless and until a Responsible Officer of the
Debenture Trustee shall have received written notice thereof from the
Corporation or a holder or holders of Senior Indebtedness or from any



                                       63
<PAGE>   71

trustee therefor; and before the receipt of any such written notice, the
Debenture Trustee, subject to the provisions of Article VI of this Indenture,
shall be entitled in all respects to assume that no such facts exist; PROVIDED,
HOWEVER, that if the Debenture Trustee shall not have received the notice
provided for in this Section 15.06 at least two Business Days prior to the date
upon which, by the terms hereof, any money may become payable for any purpose
(including, without limitation, the payment of the principal of (or premium, if
any) or interest (including Compounded Interest and Additional Sums, if any) and
Liquidated Damages, if any, on any Security), then, anything herein contained to
the contrary notwithstanding, the Debenture Trustee shall have full power and
authority to receive such money and to apply the same to the purposes for which
they were received, and shall not be affected by any notice to the contrary that
may be received by it within two Business Days prior to such date.

         The Debenture Trustee, subject to the provisions of Article VI of this
Indenture, shall be entitled to conclusively rely on a written notice delivered
to it by a Person representing himself to be a holder of Senior Indebtedness of
the Corporation (or a trustee on behalf of such holder), as the case may be, to
establish that such notice has been given by a holder of such Senior
Indebtedness or a trustee on behalf of any such holder or holders. In the event
that the Debenture Trustee determines in good faith that further evidence is
required with respect to the right of any Person as a holder of such Senior
Indebtedness to participate in any payment or distribution pursuant to this
Article XV, the Debenture Trustee may request such Person to furnish evidence to
the reasonable satisfaction of the Debenture Trustee as to the amount of such
Senior Indebtedness held by such Person, the extent to which such Person is
entitled to participate in such payment or distribution and any other facts
pertinent to the rights of such Person under this Article XV, and, if such
evidence is not furnished, the Debenture Trustee may defer any payment to such
Person pending judicial determination as to the right of such Person to receive
such payment.

         Upon any payment or distribution of assets of the Corporation referred
to in this Article XV, the Debenture Trustee, subject to the provisions of
Article VI of this Indenture, and the Securityholders shall be entitled to
conclusively rely upon any order or decree entered by any court of competent
jurisdiction in which such insolvency, bankruptcy, receivership, liquidation,
reorganization, dissolution, winding-up or similar case or proceeding is
pending, or a certificate of the trustee in bankruptcy, liquidating trustee,
custodian, receiver, assignee for the benefit of creditors, agent or other
person making such payment or distribution, delivered to the Debenture Trustee
or to the Securityholders, for the purpose of ascertaining the persons entitled
to participate in such payment or distribution, the holders of Senior
Indebtedness and other indebtedness of the Corporation, the amount thereof or
payable thereon, the amount or amounts paid or distributed thereon and all other
facts pertinent thereto or to this Article XV.

         SECTION 15.07 RIGHTS OF THE DEBENTURE TRUSTEE; HOLDERS OF SENIOR
INDEBTEDNESS.

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



                                       64
<PAGE>   72

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

         Nothing in this Article XV shall apply to claims of, or payments to,
the Debenture Trustee under or pursuant to Section 6.06.

         SECTION 15.08 SUBORDINATION MAY NOT BE IMPAIRED.

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

         Without in any way limiting the generality of the foregoing paragraph,
the holders of Senior Indebtedness of the Corporation may, at any time and from
time to time, without the consent of or notice to the Debenture Trustee or the
Securityholders, without incurring responsibility to the Securityholders and
without impairing or releasing the subordination provided in this Article XV or
the obligations hereunder of the holders of the Securities to the holders of
such Senior Indebtedness, do any one or more of the following: (i) change the
manner, place or terms of payment or extend the time of payment of, or renew or
alter, such Senior Indebtedness, or otherwise amend or supplement in any manner
such Senior Indebtedness or any instrument evidencing the same or any agreement
under which such Senior Indebtedness is outstanding; (ii) sell, exchange,
release or otherwise deal with any property pledged, mortgaged or otherwise
securing such Senior Indebtedness; (iii) release any Person liable in any manner
for the collection of such Senior Indebtedness; and (iv) exercise or refrain
from exercising any rights against the Corporation, as the case may be, and any
other Person.


                                   ARTICLE XVI
                      EXTENSION OF INTEREST PAYMENT PERIOD

         SECTION 16.01 EXTENSION OF INTEREST PAYMENT PERIOD.

         So long as no Event of Default has occurred and is continuing, the
Corporation shall have the right, at any time and from time to time during the
term of the Securities, to defer payments of interest by extending the interest
payment period of such Securities for a period not exceeding



                                       65
<PAGE>   73

10 consecutive semi-annual periods, including the first such semi-annual period
during such extension period (the "Extended Interest Payment Period"), during
which Extended Interest Payment Period no interest shall be due and payable,
PROVIDED that no Extended Interest Payment Period shall end on a date other than
an Interest Payment Date or extend beyond the Maturity Date. To the extent
permitted by applicable law, interest, the payment of which has been deferred
because of the extension of the interest payment period pursuant to this Section
16.01, will bear interest thereon at the Coupon Rate compounded semi-annually
for each semi-annual period during the Extended Interest Payment Period
("Compounded Interest"). At the end of the Extended Interest Payment Period, the
Corporation shall pay all interest accrued and unpaid on the Securities,
including any Additional Sums and Compounded Interest (together, "Deferred
Interest"), that shall be payable to the holders of the Securities in whose
names the Securities are registered in the Security Register on the record date
immediately preceding the end of the Extended Interest Payment Period. Before
the termination of any Extended Interest Payment Period, the Corporation may
further defer payments of interest by further extending such Extended Interest
Payment Period, PROVIDED that such Extended Interest Payment Period, together
with all such previous and further extensions within such Extended Interest
Payment Period, shall not (i) exceed 10 consecutive semi-annual periods,
including the first such semi-annual period during such Extended Interest
Payment Period, (ii) end on a date other than an Interest Payment Date or (iii)
extend beyond the Maturity Date of the Securities. Upon the termination of any
Extended Interest Payment Period and the payment of all amounts then due, the
Corporation may commence a new Extended Interest Payment Period, subject to the
foregoing requirements. No interest shall be due and payable during an Extended
Interest Payment Period, except at the end thereof, but the Corporation may
prepay at any time all or any portion of the interest accrued during an Extended
Interest Payment Period.

         SECTION 16.02 NOTICE OF EXTENSION.

         (a) If the Property Trustee is the only holder of the Securities at the
time the Corporation elects to commence an Extended Interest Payment Period, the
Corporation shall give written notice to the Administrative Trustees, the
Property Trustee and the Debenture Trustee of its election to commence such
Extended Interest Payment Period at least five Business Days before the earlier
of (i) the next succeeding date on which Distributions on the Trust Securities
would have been payable, and (ii) the date the Property Trustee is required to
give notice of the record date, or the date such Distributions are payable, to
any national securities exchange or to holders of the Capital Securities, but in
any event at least five Business Days before such record date.

         (b) If the Property Trustee is not the only holder of the Securities at
the time the Corporation elects to commence an Extended Interest Payment Period,
the Corporation shall give the holders of the Securities and the Debenture
Trustee written notice of its election of such Extended Interest Payment Period
at least 10 Business Days before the earlier of (i) the next succeeding Interest
Payment Date, and (ii) the date the Debenture Trustee is required to give notice
of the record or payment date of such interest payment to any national
securities exchange.



                                       66
<PAGE>   74

         (c) The semi-annual period in which any notice is given pursuant to
paragraphs (a) or (b) of this Section 16.02 shall be counted as one of the 10
semi-annual periods permitted in the maximum Extended Interest Payment Period
permitted under Section 16.01.

         Wilmington Trust Company hereby accepts the trusts in this Indenture
declared and provided, upon the terms and conditions hereinabove set forth.


                                       67
<PAGE>   75

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

                                     SKY FINANCIAL GROUP, INC.


                                     By:________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________



                                     WILMINGTON TRUST COMPANY,
                                     as Debenture Trustee


                                     By:________________________________________
                                     Name:______________________________________
                                     Title:_____________________________________


                                       68
<PAGE>   76


                                    EXHIBIT A
                                    ---------

                           (FORM OF FACE OF SECURITY)

         [IF THIS SECURITY IS A GLOBAL SECURITY INSERT: THIS SECURITY IS A
GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND
IS REGISTERED IN THE NAME OF THE DEPOSITORY TRUST COMPANY ("DTC") OR A NOMINEE
OF DTC. THIS SECURITY IS EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A
PERSON OTHER THAN DTC OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED
IN THE INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER OF
THIS SECURITY AS A WHOLE BY DTC TO A NOMINEE OF DTC OR BY A NOMINEE OF DTC TO
DTC OR ANOTHER NOMINEE OF DTC) MAY BE REGISTERED EXCEPT IN LIMITED
CIRCUMSTANCES.

         UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
DTC TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN
SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY
AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF
FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL IN AS MUCH AS THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

         THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS OR ANY OTHER
APPLICABLE SECURITIES LAW. NEITHER THIS SECURITY NOR ANY INTEREST OR
PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED,
ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR
UNLESS SUCH TRANSACTION IS EXEMPT FROM, OR NOT SUBJECT TO, REGISTRATION.

         THE HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF AGREES TO OFFER,
SELL OR OTHERWISE TRANSFER THIS SECURITY, PRIOR TO THE DATE (THE "RESALE
RESTRICTION TERMINATION DATE") WHICH IS TWO YEARS AFTER THE LATER OF THE
ORIGINAL ISSUANCE DATE HEREOF AND THE LAST DATE ON WHICH SKY FINANCIAL GROUP,
INC. (THE "CORPORATION") OR ANY "AFFILIATE" OF THE CORPORATION WAS THE OWNER OF
THIS SECURITY (OR ANY PREDECESSOR OF THIS SECURITY) ONLY (A) TO THE CORPORATION,
(B) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER
THE SECURITIES ACT, (C) SO LONG AS THIS SECURITY IS ELIGIBLE FOR RESALE PURSUANT
TO RULE 144A UNDER THE SECURITIES ACT ("RULE 144A"), TO A PERSON IT REASONABLY
BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A) THAT
PURCHASES FOR ITS

                                      A-1

<PAGE>   77

OWN ACCOUNT OR FOR THE ACCOUNT OF QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE
IS GIVEN THAT THE TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) TO AN
INSTITUTIONAL "ACCREDITED INVESTOR" WITHIN THE MEANING OF SUBPARAGRAPH (a)(1),
(2), (3) OR (7) OF RULE 501 UNDER THE SECURITIES ACT THAT IS ACQUIRING THIS
SECURITY FOR ITS OWN ACCOUNT, OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL
ACCREDITED INVESTOR, FOR INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR FOR
OFFER OR SALE IN CONNECTION WITH, ANY DISTRIBUTION IN VIOLATION OF THE
SECURITIES ACT, OR (E) PURSUANT TO ANY OTHER AVAILABLE EXEMPTION FROM THE
REGISTRATION REQUIREMENTS UNDER THE SECURITIES ACT, SUBJECT TO THE RIGHT OF THE
CORPORATION PRIOR TO ANY SUCH OFFER, SALE OR TRANSFER (i) PURSUANT TO CLAUSE (D)
OR (E) TO REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATIONS AND/OR
OTHER INFORMATION SATISFACTORY TO THE CORPORATION, AND (ii) PURSUANT TO CLAUSE
(D) TO REQUIRE THAT A CERTIFICATE OF TRANSFER IN THE FORM APPEARING ON THE
REVERSE OF THIS SECURITY IS COMPLETED AND DELIVERED BY THE TRANSFEREE TO THE
CORPORATION. SUCH HOLDER FURTHER AGREES THAT IT WILL DELIVER TO EACH PERSON TO
WHOM THIS SECURITY IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS
LEGEND.

         THE SECURITIES WILL BE ISSUED AND MAY BE TRANSFERRED ONLY IN BLOCKS
HAVING AN AGGREGATE PRINCIPAL AMOUNT OF NOT LESS THAN $100,000. ANY ATTEMPTED
TRANSFER OF SECURITIES IN A BLOCK HAVING AN AGGREGATE PRINCIPAL AMOUNT OF LESS
THAN $100,000 AND MULTIPLES OF $1,000 IN EXCESS THEREOF SHALL BE DEEMED TO BE
VOID AND OF NO LEGAL EFFECT WHATSOEVER. ANY SUCH PURPORTED TRANSFEREE SHALL BE
DEEMED NOT TO BE THE HOLDER OF SUCH SECURITIES FOR ANY PURPOSE, INCLUDING, BUT
NOT LIMITED TO, THE RECEIPT OF PRINCIPAL OF OR INTEREST ON SUCH SECURITIES, AND
SUCH PURPORTED TRANSFEREE SHALL BE DEEMED TO HAVE NO INTEREST WHATSOEVER IN SUCH
SECURITIES.

         THE HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF ALSO AGREES,
REPRESENTS AND WARRANTS THAT IT IS NOT AN EMPLOYEE BENEFIT, INDIVIDUAL
RETIREMENT ACCOUNT OR OTHER PLAN OR ARRANGEMENT SUBJECT TO TITLE I OF THE
EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE") (EACH
A "PLAN"), OR AN ENTITY WHOSE UNDERLYING ASSETS INCLUDE "PLAN ASSETS" BY REASON
OF ANY PLAN'S INVESTMENT IN THE ENTITY, AND NO PERSON INVESTING "PLAN ASSETS" OF
ANY PLAN MAY ACQUIRE OR HOLD THE SECURITIES OR ANY INTEREST THEREIN, UNLESS SUCH
PURCHASER OR HOLDER IS ELIGIBLE FOR THE EXEMPTIVE RELIEF AVAILABLE UNDER U.S.
DEPARTMENT OF LABOR PROHIBITED TRANSACTION CLASS EXEMPTION 96-23, 95-60, 91-38,
90-1 OR 84-14 OR ANOTHER APPLICABLE EXEMPTION OR ITS PURCHASE AND HOLDING OF
THIS SECURITY IS NOT PROHIBITED BY SECTION 406 OF ERISA OR SECTION 4975 OF THE
CODE WITH RESPECT TO SUCH PURCHASE OR HOLDING. ANY PURCHASER

                                      A-2

<PAGE>   78

OR HOLDER OF THE SECURITIES OR ANY INTEREST THEREIN WILL BE DEEMED TO HAVE
REPRESENTED BY ITS PURCHASE AND HOLDING THEREOF THAT EITHER (i) IT IS NOT AN
EMPLOYEE BENEFIT PLAN WITHIN THE MEANING OF SECTION 3(3) OF ERISA, OR A PLAN TO
WHICH SECTION 4975 OF THE CODE IS APPLICABLE, A TRUSTEE OR OTHER PERSON ACTING
ON BEHALF OF AN EMPLOYEE BENEFIT PLAN OR PLAN, OR ANY OTHER PERSON OR ENTITY
USING THE ASSETS OF ANY EMPLOYEE BENEFIT PLAN OR PLAN TO FINANCE SUCH PURCHASE,
OR (ii) SUCH PURCHASE WILL NOT RESULT IN A PROHIBITED TRANSACTION UNDER SECTION
406 OF ERISA OR SECTION 4975 OF THE CODE FOR WHICH THERE IS NO APPLICABLE
STATUTORY OR ADMINISTRATIVE EXEMPTION.

         THE HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF AGREES TO BE BOUND
BY THE REGISTRATION RIGHTS AGREEMENT, DATED AS OF MARCH 28, 2000, BY AND AMONG
THE TRUST, THE ISSUER AND THE INITIAL PURCHASER NAMED THEREIN, AS AMENDED FROM
TIME TO TIME.

                                      A-3
<PAGE>   79



                       SUBORDINATED DEBENTURE CERTIFICATE
                            SKY FINANCIAL GROUP, INC.

CUSIP No.: _____________
         $

             9.34% JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURE

                       DUE MAY 1, 2030, Series A/Series B

         SKY FINANCIAL GROUP, INC., an Ohio corporation (the "Corporation,"
which term includes any successor Person under the Indenture hereinafter
referred to), for value received, hereby promises to pay to Sky Financial
Capital Trust I or registered assigns, the principal sum of
__________________________________ Dollars ($______) on May 1, 2030 (the
"Maturity Date"), unless previously prepaid, and to pay interest on the
outstanding principal amount hereof from March 31, 2000, or from the most recent
interest payment date (each such date, an "Interest Payment Date") to which
interest has been paid or duly provided for, semi-annually (subject to deferral
as set forth herein) in arrears on May 1st and November 1st of each year,
commencing November 1, 2000 at the rate of 9.34% per annum, until the principal
hereof shall have become due and payable, and on any overdue principal and
premium, if any, and (without duplication and to the extent that payment of such
interest is enforceable under applicable law) on any overdue installment of
interest at the same rate per annum compounded semi-annually ("Compounded
Interest"). The amount of interest payable hereon shall be computed on the basis
of a 360-day year of twelve 30-day months. In the event that any date on which
the principal of (or premium, if any) or interest on this Security is payable is
not a Business Day (as defined in the Indenture), then the payment payable on
such date will be made on the next succeeding day that is a Business Day, except
that if such next succeeding Business Day falls in the next succeeding calendar
year such payment shall be made on the immediately preceding Business Day (and
without any interest or other payment in respect of any such delay), with the
same force and effect as if made on such date. Pursuant to the Indenture, in
certain circumstances the Corporation will be required to pay Additional Sums
(as defined in the Indenture) with respect to this Security. Pursuant to the
Registration Rights Agreement and the Liquidated Damages Agreement, in certain
limited circumstances the Corporation will be required to pay Liquidated Damages
(as defined in the Registration Rights Agreement and the Liquidated Damages
Agreement) with respect to this Security.

         The interest installment so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in the Indenture,
be paid to the Person in whose name this Security (or one or more Predecessor
Securities, as defined in said Indenture) is registered at the close of business
on the regular record date for such interest installment, which shall be at the
close of business on the 15th day of the month immediately preceding the month
in which the relevant Interest Payment Date falls. Any such interest installment
not punctually paid or duly provided for shall forthwith cease to be payable to
the holders on such regular record date and may be paid to the Person in whose
name this Security (or one or more Predecessor Securities) is registered at the
close of business on a special record date to be fixed by the Debenture Trustee


                                      A-4
<PAGE>   80

for the payment of such defaulted interest, notice whereof shall be given to the
holders of Securities not less than 10 days prior to such special record date,
or may be paid at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange on which the Securities may be listed,
and upon such notice as may be required by such exchange, all as more fully
provided in the Indenture.

         The principal of (and premium, if any) and interest (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
on this Security shall be payable at the office or agency of the Debenture
Trustee maintained for that purpose in any coin or currency of the United States
of America that at the time of payment is legal tender for payment of public and
private debts; PROVIDED, HOWEVER, that payment of interest may be made at the
option of the Corporation by (i) check mailed to the holder at such address as
shall appear in the Security Register or (ii) transfer to an account maintained
by the Person entitled thereto, provided that proper written transfer
instructions have been received by the relevant record date. Notwithstanding the
foregoing, so long as the holder of this Security is the Property Trustee of Sky
Financial Capital Trust I, the payment of the principal of (and premium, if any)
and interest (including Compounded Interest and Additional Sums, if any) and
Liquidated Damages, if any, on this Security will be made at such place and to
such account as may be designated by such Property Trustee.

         The indebtedness evidenced by this Security is, to the extent provided
in the Indenture, subordinate and junior in right of payment to the prior
payment in full of all Senior Indebtedness, and this Security is issued subject
to the provisions of the Indenture with respect thereto. Each holder of this
Security, by accepting the same, (a) agrees to and shall be bound by such
provisions, (b) authorizes and directs the Debenture Trustee on his or her
behalf to take such action as may be necessary or appropriate to acknowledge or
effectuate the subordination so provided and (c) appoints the Debenture Trustee
his or her attorney-in-fact for any and all such purposes. Each holder hereof,
by his or her acceptance hereof, hereby waives all notice of the acceptance of
the subordination provisions contained herein and in the Indenture by each
holder of Senior Indebtedness, whether now outstanding or hereafter incurred,
and waives reliance by each such holder upon said provisions.

         This Security shall not be entitled to any benefit under the Indenture
or be valid or become obligatory for any purpose until the Certificate of
Authentication hereon shall have been signed by or on behalf of the Debenture
Trustee.

         The provisions of this Security are continued on the reverse side
hereof and such provisions shall for all purposes have the same effect as though
fully set forth at this place.


                                      A-5
<PAGE>   81

         IN WITNESS WHEREOF, the Corporation has caused this instrument to be
duly executed and sealed this ___ day of _____________, 20__.

                                           SKY FINANCIAL GROUP, INC.


                                           By:__________________________________
                                           Name:________________________________
                                           Title:_______________________________

Attest:

By:____________________________________
Name:__________________________________
Title:_________________________________





                          CERTIFICATE OF AUTHENTICATION

     This is one of the 9.34% Junior Subordinated Deferrable Interest
Debentures, Series A/Series B, of SKY FINANCIAL GROUP, INC. referred to in the
within-mentioned Indenture.


                                    WILMINGTON TRUST COMPANY,
                                    not in its individual capacity but solely as
                                    Debenture Trustee



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


                                      A-6
<PAGE>   82

                                           (FORM OF REVERSE OF SECURITY)

         This Security is one of the Securities of the Corporation (herein
sometimes referred to as the "Securities"), specified in the Indenture, all
issued or to be issued under and pursuant to an Indenture, dated as of April
___, 2000 (the "Indenture"), duly executed and delivered between the Corporation
and Wilmington Trust Company, as Debenture Trustee (the "Debenture Trustee"), to
which Indenture reference is hereby made for a description of the rights,
limitations of rights, obligations, duties and immunities thereunder of the
Debenture Trustee, the Corporation and the holders of the Securities.

         Upon the occurrence and continuation of a Special Event (as defined in
the Indenture) prior to May 1, 2010 (the "Initial Optional Redemption Date"),
the Corporation shall have the right, at any time within 90 days following the
occurrence of such Special Event, to prepay this Security in whole (but not in
part) at the Special Event Prepayment Price. "Special Event Prepayment Price"
shall mean, with respect to any prepayment of the Securities following a Special
Event, an amount in cash equal to the greater of (i) 100% of the principal
amount of the Securities to be prepaid, or (ii) the sum, as determined by a
Quotation Agent, of the present values of the remaining scheduled payments of
principal and interest on such Securities, discounted to the prepayment date on
a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months)
at the Adjusted Treasury Rate, plus, in the case of each of (i) and (ii), any
accrued and unpaid interest (including Compounded Interest and Additional Sums,
if any) and Liquidated Damages, if any, thereon to the date of such prepayment.

         In addition, the Corporation shall have the right to prepay this
Security, in whole or in part, at any time on or after the Initial Optional
Redemption Date (an "Optional Prepayment"), at the prepayment prices set forth
below plus, in each case, accrued and unpaid interest thereon (including
Compounded Interest and Additional Sums, if any) and Liquidated Damages, if any,
thereon to the applicable date of prepayment (the "Optional Prepayment Price"),
if prepaid during the 12-month period beginning May 1, of the years indicated
below.

               Year                            Percentage of Principal
               ----                            -----------------------

               2010                                    104.670%
               2011                                    104.203%
               2012                                    103.736%
               2013                                    103.269%
               2014                                    102.802%
               2015                                    102.335%
               2016                                    101.868%
               2017                                    101.401%
               2018                                    100.934%
               2019                                    100.467%
               2020 and thereafter                     100.000%



                                      A-7
<PAGE>   83

         The Prepayment Price shall be paid prior to 12:00 noon, New York City
time, on the date of such prepayment or at such earlier time as the Corporation
determines, PROVIDED that the Corporation shall deposit with the Debenture
Trustee an amount sufficient to pay the Prepayment Price by 10:00 a.m., New York
City time, on the date such Prepayment Price is to be paid. Any prepayment
pursuant to this paragraph will be made upon not less than 30 days nor more than
60 days' prior written notice.

         If the Securities are only partially prepaid by the Corporation
pursuant to an Optional Prepayment, the particular Securities to be prepaid
shall be selected on a pro rata basis from the outstanding Securities not
previously called for prepayment; PROVIDED, HOWEVER, that with respect to
Securityholders that would be required to hold Securities with an aggregate
principal amount of less than $100,000 but more than an aggregate principal
amount of zero as a result of such pro rata prepayment, the Corporation shall
prepay Securities of each such Securityholder so that after such prepayment such
Securityholder shall hold Securities either with an aggregate principal amount
of at least $100,000 or such Securityholder no longer holds any Securities and
shall use such method (including, without limitation, by lot) as the Corporation
shall deem fair and appropriate; PROVIDED, FURTHER, that any such proration may
be made on the basis of the aggregate principal amount of Securities held by
each Securityholder thereof and may be made by making such adjustments as the
Corporation deems fair and appropriate in order that only Securities in
denominations of $1,000 or integral multiples thereof shall be prepaid. In the
event of prepayment of this Security in part only, a new Security or Securities
for the portion hereof that has not been prepaid will be issued in the name of
the holder hereof upon the cancellation hereof.

         Notwithstanding the foregoing, any prepayment of Securities by the
Corporation shall be subject to the receipt of any and all required regulatory
approvals.

         In case an Event of Default (as defined in the Indenture) shall have
occurred and be continuing, the principal of all of the Securities may be
declared, and upon such 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 Corporation and the
Debenture Trustee, with the consent of the holders of a majority in aggregate
principal amount of the Securities at the time outstanding (as defined in the
Indenture), to execute supplemental indentures for the purpose of adding any
provisions to or changing in any manner or eliminating any of the provisions of
the Indenture or of modifying in any manner the rights of the holders of the
Securities; PROVIDED, HOWEVER, that no such supplemental indenture shall,
without the consent of each holder of Securities then outstanding and affected
thereby, (i) change the Maturity Date of any Security, or reduce the rate or
extend the time of payment of interest thereon (subject to Article XVI of the
Indenture), or reduce the principal amount thereof, or change any of the
prepayment provisions or make the principal thereof or any interest or premium
thereon payable in any coin or currency other than U.S. dollars, or impair or
affect the right of any holder of Securities to institute suit for payment
thereof, or (ii) reduce the aforesaid percentage of Securities the holders of
which are required to consent to any such supplemental indenture. The



                                      A-8
<PAGE>   84

Indenture also contains provisions permitting the holders of a majority in
aggregate principal amount of the Securities at the time outstanding affected
thereby, on behalf of all of the holders of the Securities, to waive any past
default in the performance of any of the covenants contained in the Indenture,
or established pursuant to the Indenture, and its consequences, except a default
in the payment of the principal of or premium, if any, or interest on any of the
Securities or a default in respect of any covenant or provision under which the
Indenture cannot be modified or amended without the consent of each holder of
Securities then outstanding. Any such consent or waiver by the holder of this
Security (unless revoked as provided in the Indenture) shall be conclusive and
binding upon such holder and upon all future holders and owners of this Security
and of any Security issued in exchange herefor or in place hereof (whether by
registration of transfer or otherwise), irrespective of whether or not any
notation of such consent or waiver is made upon this Security.

         No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Corporation,
which is absolute and unconditional, to pay the principal of (and premium, if
any) and interest (including Compounded Interest and Additional Sums, if any)
and Liquidated Damages, if any, on this Security at the time and place and at
the rate and in the money herein prescribed.

         So long as no Event of Default shall have occurred and be continuing,
the Corporation shall have the right, at any time and from time to time during
the term of the Securities, to defer payments of interest by extending the
interest payment period (an "Extended Interest Payment Period") of such
Securities for a period not (i) exceeding 10 consecutive semi-annual periods,
including the first such semi-annual period during such extension period, (ii)
extending beyond the Maturity Date of the Securities or (iii) ending on a date
other than an Interest Payment Date, at the end of which period the Corporation
shall pay all interest then accrued and unpaid (together with interest thereon
at the rate specified for the Securities to the extent that payment of such
interest is enforceable under applicable law). Before the termination of any
such Extended Interest Payment Period, the Corporation may further defer
payments of interest by further extending such Extended Interest Payment Period,
PROVIDED that such Extended Interest Payment Period, together with all such
previous and further extensions within such Extended Interest Payment Period,
(i) shall not exceed 10 consecutive semi-annual periods including the first
semi-annual period during such Extended Interest Payment Period, (ii) shall not
end on any date other than an Interest Payment Date, and (iii) shall not extend
beyond the Maturity Date of the Securities. Upon the termination of any such
Extended Interest Payment Period and the payment of all accrued and unpaid
interest and any additional amounts then due, the Corporation may commence a new
Extended Interest Payment Period, subject to the foregoing requirements. No
interest shall be due and payable during an Extended Interest Payment Period,
except at the end thereof, but the Corporation may prepay at any time all or any
portion of the interest accrued during an Extended Interest Payment Period.

         The Corporation has agreed that it will not (i) declare or pay any
dividends or distributions on, or redeem, purchase, acquire, or make a
liquidation payment with respect to, any of the Corporation's capital stock,
(ii) make any payment of principal of or interest or premium, if any, on or
repay, repurchase or redeem any debt securities (including other Debentures) of
the Corporation that rank pari passu with or junior in right of payment to the


                                      A-9
<PAGE>   85

Securities or (iii) make any guarantee payments with respect to any guarantee by
the Corporation of the debt securities of any Subsidiary of the Corporation
(including Other Guarantees) if such guarantee ranks pari passu with or junior
in right of payment to the Securities (other than (a) dividends or distributions
of Corporation's capital stock (which includes Common Stock and preferred
stock), (b) any declaration of a dividend in connection with the implementation
of a stockholders' rights plan, or the issuance of stock under any such plan in
the future, or the redemption or repurchase of any such rights pursuant thereto,
(c) payments under the Capital Securities Guarantee, as defined in the
Indenture, (d) as a result of a reclassification of the Corporation's capital
stock or the exchange or conversion of one class or series of the Corporation's
capital stock for another class or series of the Corporation's capital stock,
(e) the purchase of fractional interests in shares of the Corporation's capital
stock pursuant to the conversion or exchange provisions of such capital stock or
the security being converted or exchanged, and (f) purchases of Common Stock
related to the issuance of Common Stock or rights under any of the Corporation's
benefit or compensation plans for its directors, officers or employees or any of
the Corporation's dividend reinvestment plans), if at such time (1) there shall
have occurred any event of which the Corporation has actual knowledge that (a)
is, or with the giving of notice or the lapse of time, or both, would
constitute, an Event of Default and (b) in respect of which the Corporation
shall not have taken reasonable steps to cure, (2) if such Securities are held
by the Property Trustee of Sky Financial Capital Trust I, the Corporation shall
be in default with respect to its payment of any obligations under the Capital
Securities Guarantee or (3) the Corporation shall have given notice of its
election to exercise its right to commence an Extended Interest Payment Period,
and shall not have rescinded such Notice, and such Extended Interest Payment
Period or any extension thereof shall have commenced and be continuing.

         Subject to (i) the Corporation having received any required regulatory
approvals and (ii) the Administrative Trustees of Sky Financial Capital Trust I
having received an opinion of counsel to the effect that such distribution will
not cause the holders of Capital Securities to recognize gain or loss for
federal income tax purposes, the Corporation will have the right at any time to
liquidate the Trust and, after satisfaction of liabilities of creditors of the
Trust as required by applicable law, to cause the Securities to be distributed
to the holders of the Trust Securities in liquidation of the Trust.

         The Securities are issuable only in registered form without coupons in
minimum denominations of $100,000 and multiples of $1,000 in excess thereof. As
provided in the Indenture and subject to the transfer restrictions limitations
as may be contained herein and therein from time to time, this Security is
transferable by the holder hereof on the Security Register of the Corporation,
upon surrender of this Security for registration of transfer at the office or
agency of the Corporation in Wilmington, Delaware accompanied by a written
instrument or instruments of transfer in form satisfactory to the Corporation or
the Debenture Trustee duly executed by the holder hereof or his or her attorney
duly authorized in writing, and thereupon one or more new Securities of
authorized denominations and for the same aggregate principal amount will be
issued to the designated transferee or transferees. No service charge will be
made for any such registration of transfer, but the Corporation may require
payment of a sum sufficient to cover any tax or other governmental charge
payable in relation thereto.



                                      A-10
<PAGE>   86

         Prior to due presentment for registration of transfer of this Security,
the Corporation, the Debenture Trustee, any authenticating agent, any paying
agent, any transfer agent and the security registrar may deem and treat the
holder hereof as the absolute owner hereof (whether or not this Security shall
be overdue and notwithstanding any notice of ownership or writing hereon made by
anyone other than the security registrar for the Securities) for the purpose of
receiving payment of or on account of the principal hereof and premium, if any,
and (subject to the Indenture) interest due hereon and for all other purposes,
and neither the Corporation nor the Debenture Trustee nor any authenticating
agent nor any paying agent nor any transfer agent nor any security registrar
shall be affected by any notice to the contrary.

         No recourse shall be had for the payment of the principal of or
premium, if any, or interest (including Compounded Interest and Additional Sums,
if any) or Liquidated Damages, if any, on this Security, or for any claim based
hereon, or otherwise in respect hereof, or based on or in respect of the
Indenture, against any incorporator, stockholder, employee, officer or director,
past, present or future, as such, of the Corporation or of any predecessor or
successor Person, 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 the acceptance hereof and as part of the consideration for
the issuance hereof, expressly waived and released.

         All terms used in this Security that are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

         THE INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO CONFLICT OF
LAW PRINCIPLES THEREOF.


                                      A-11