<PAGE>   1
                                                                    EXHIBIT 4.10
                                                                    ------------



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


                 SERIES B CAPITAL SECURITIES GUARANTEE AGREEMENT

                            SKY FINANCIAL GROUP, INC.

                        DATED AS OF ______________, 2000


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




<PAGE>   2


<TABLE>
<CAPTION>

                                                TABLE OF CONTENTS

                                                                                                 PAGE
                                                                                                 ----
<S>                   <C>                                                                         <C>
ARTICLE I             DEFINITIONS AND INTERPRETATION...............................................2
     Section 1.1           Definitions and Interpretation..........................................2

ARTICLE II            TRUST INDENTURE ACT..........................................................6
     Section 2.1           Trust Indenture Act; Application........................................6
     Section 2.2           Lists of Holders of Securities..........................................6
     Section 2.3           Reports by the Capital Securities Guarantee Trustee.....................7
     Section 2.4           Periodic Reports........................................................7
     Section 2.5           Evidence of Compliance with Conditions Precedent........................7
     Section 2.6           Waiver of Events of Default.............................................7
     Section 2.7           Notice of Events of Default.............................................7
     Section 2.8           Conflicting Interests...................................................8

ARTICLE III           POWERS, DUTIES AND RIGHTS OF CAPITAL
                      SECURITIES GUARANTEE TRUSTEE.................................................8
     Section 3.1           Powers and Duties of the Capital Securities Guarantee Trustee...........8
     Section 3.2           Certain Rights of Capital Securities Guarantee Trustee.................10
     Section 3.3           Not Responsible for Recitals or Issuance of Series B Capital
                            Securities Guarantee..................................................12

ARTICLE IV            CAPITAL SECURITIES GUARANTEE TRUSTEE........................................12
     Section 4.1           Capital Securities Guarantee Trustee; Eligibility......................12
     Section 4.2           Appointment, Removal and Resignation of Common Securities
                            Guarantee Trustee.....................................................13

ARTICLE V             GUARANTEE...................................................................14
     Section 5.1           Guarantee..............................................................14
     Section 5.2           Waiver of Notice and Demand............................................14
     Section 5.3           Obligations Not Affected...............................................14
     Section 5.4           Rights of Holders......................................................15
     Section 5.5           Guarantee of Payment...................................................15
     Section 5.6           Subrogation............................................................15
     Section 5.7           Independent Obligations................................................15

ARTICLE VI            LIMITATION OF TRANSACTIONS; SUBORDINATION...................................16
     Section 6.1           Limitation of Transactions.............................................16
     Section 6.2           Ranking................................................................16

ARTICLE VII           TERMINATION.................................................................17
     Section 7.1           Termination............................................................17
</TABLE>



                                      -i-

<PAGE>   3

<TABLE>
<S>                   <C>                                                                         <C>
ARTICLE VIII          INDEMNIFICATION.............................................................17
     Section 8.1           Exculpation............................................................17
     Section 8.2           Compensation and Indemnification.......................................17

ARTICLE IX            MISCELLANEOUS...............................................................18
     Section 9.1           Successors and Assigns.................................................18
     Section 9.2           Amendments.............................................................18
     Section 9.3           Notices................................................................18
     Section 9.5           Governing Law..........................................................19
</TABLE>





                                      -ii-

<PAGE>   4



                             CROSS REFERENCE TABLE*



SECTION OF TRUST INDENTURE                          SECTION OF GUARANTEE
ACT OF 1939, AS AMENDED                                   AGREEMENT
--------------------------                          --------------------

     310(a)       ...............................      4.1(a)
     310(b)       ...............................      2.8, 4.1(c)
     310(c)       ...............................      N/A
     311(a)       ...............................      2.2(b)
     311(b)       ...............................      2.2(b)
     311(c)       ...............................      N/A
     312(a)       ...............................      2.2(a)
     312(b)       ...............................      2.2(b)
     312(c)       ...............................      N/A
     313          ...............................      2.3
     314(a)       ...............................      2.4
     314(b)       ...............................      N/A
     314(c)       ...............................      2.5
     314(d)       ...............................      N/A
     314(e)       ...............................      1.1, 2.5, 3.2
     314(f)       ...............................      2.1, 3.2
     315(a)       ...............................      3.1(d), 3.2(a)
     315(b)       ...............................      2.7
     315(c)       ...............................      3.1(c)
     315(d)       ...............................      3.1(d), 3.2(a), 8.1
     315(e)       ...............................      N/A
     316(a)       ...............................      1.1, 2.6, 5.4
     316(b)       ...............................      5.3, 5.4
     316(c)       ...............................      9.2
     317(a)       ...............................      N/A
     317(b)       ...............................      N/A
     318(a)       ...............................      2.1(a)
     318(b)       ...............................      2.1(b)
     318(c)       ...............................      2.1(b)





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

*  This Cross-Reference Table does not constitute part of this Guarantee
   Agreement and shall not affect the interpretation of any of its items
   or provisions.


                                     -iii-

<PAGE>   5



                      SERIES B CAPITAL SECURITIES GUARANTEE



         THIS SERIES B CAPITAL SECURITIES GUARANTEE AGREEMENT (the "Series B
Capital Securities Guarantee") dated as of _____________, 2000, is executed and
delivered by SKY FINANCIAL GROUP, INC., an Ohio corporation (the "Guarantor"),
and WILMINGTON TRUST COMPANY, a Delaware banking corporation, as trustee (the
"Capital Securities Guarantee Trustee" or "Trustee"), for the benefit of the
Holders (as defined herein) from time to time of the Series B Capital Securities
Guarantee (as defined herein) of SKY FINANCIAL CAPTIAL TRUST I, a Delaware
statutory business trust (the "Issuer").

         WHEREAS, pursuant to an Amended and Restated Declaration of Trust (the
"Declaration"), dated as of March 31, 2000, by and among the trustees of the
Issuer named therein, the Guarantor, as sponsor, and the Holders from time to
time of undivided beneficial interests in the assets of the issuer, the Issuer
(i) issued on March 31, 2000 60,000 capital securities, having an aggregate
liquidation amount of $60,000,000, such capital securities being designated the
9.34% Capital Securities, Series A (collectively, the "Series A Capital
Securities") and (ii) in connection with an Exchange Offer (as defined in the
Declaration), hereby executes and delivers this Series B Capital Securities
Guarantee (as defined in the Declaration) for the benefit of Holders of the
Series B Capital Securities (as defined in the Declaration).

         WHEREAS, the Series A Capital Securities issued by the issuer and
proceeds thereof, together with the proceeds from the issuance of the Issuer's
Common Securities (as defined herein), were used to purchase the Junior
Subordinated Debentures due May 1, 2030 (the "Series A Junior Subordinated
Debentures") of the Guarantor which were deposited with the Trustee, as Property
Trustee under the Declaration, as trust assets.

         WHEREAS, as incentive for the Holders to purchase the Series A Capital
Securities, the Guarantor irrevocably and unconditionally agreed, to the extent
set forth in the Series A Capital Securities Guarantee dated as of March 31,
2000, to pay the Guarantee Payments (as defined herein) to the Holders of the
Series A Capital Securities, and the Guarantor agrees to make certain other
payments on the terms and conditions set forth herein.

         WHEREAS, in connection with the offer of the Series A Capital
Securities, the Guarantor, the Issuer and Sandler O'Neill Partners, L.P.,
executed the Registration Rights Agreement dated March 28, 2000 (the
"Registration Rights Agreement").

         WHEREAS, the Issuer, in order to satisfy its obligations under the
Registration Rights Agreement, intends to offer up to $60,000,000 aggregate
Liquidation Amount of its 9.34% Capital Securities, Series B, which have been
registered under the Securities Act of 1933, as amended, pursuant to a
registration statement in exchange for a like Liquidation Amount of Series A
Capital Securities.

<PAGE>   6


         WHEREAS, pursuant to the Exchange Offer, the Guarantor is also
exchanging up to $60,000,000 aggregate principal amount of the Series A Junior
Subordinated Debentures for up to $60,000,000 aggregate principal amount of the
Series B Junior Subordinated Debentures due May 1, 2030 of the Guarantor.

         WHEREAS, pursuant to the Exchange Offer, the Guarantor is required to
execute this Series B Capital Securities Guarantee and exchange the Series A
Capital Securities Guarantee for the Series B Capital Securities Guarantee
Agreement.

         WHEREAS, the Guarantor also executed and delivered the Common
Securities Guarantee Agreement, dated as of March 31, 2000 (the "Common
Securities Guarantee"), for the benefit of the holders of the Common Securities
(as defined herein), the terms of which provide that if an Event of Default (as
defined in the Declaration) has occurred and is continuing, the rights of
holders of the Common Securities to receive Guarantee Payments under the Common
Securities Guarantee are subordinated, to the extent and in the manner set forth
in the Common Securities Guarantee, to the rights of Holders of the Series A
Capital Securities and the Series B Capital Securities to receive Guarantee
Payments under the Series A Capital Securities Guarantee and this Series B
Capital Securities Guarantee, as the case may be.

         NOW, THEREFORE, in consideration of the exchange by each Holder of the
Series A Capital Securities for the Series B Capital Securities, which exchange
the Guarantor hereby acknowledges shall benefit the Guarantor (or in the event
certain Holders do not exchange their Series A Capital Securities, in order to
fulfill its obligations to such Holders under the Series A Capital Securities
Guarantee), and intending to be legally bound hereby, the Guarantor executes and
delivers this Series B Capital Securities Guarantee for the benefit of the
Holders from time to time of the Trust Securities (as defined herein).


                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

         SECTION 1.1    DEFINITIONS AND INTERPRETATION. In this Series B Capital
Securities Guarantee, unless the context otherwise requires:

         (a)    capitalized terms used in the Series B Capital Securities
Guarantee but not defined in the preamble above have the respective meanings
assigned to them in this Section 1.1;

         (b)    terms defined in the Declaration as in effect at the date of
execution of this Series B Capital Securities Guarantee have the same meaning
when used in this Series B Capital Securities Guarantee unless otherwise defined
in this Series B Capital Securities Guarantee;

         (c)    a term defined anywhere in this Series B Capital Securities
Guarantee has the same meaning throughout;



                                      -2-
<PAGE>   7


         (d)    all references to "the Series B Capital Securities Guarantee"
or "this Series B Capital Securities Guarantee" are references to this Series B
Capital Securities Guarantee as modified, supplemented or amended from time to
time;

         (e)    all references in this Series B Capital Securities Guarantee to
Articles and Sections are references to Articles and Sections of this Series B
Capital Securities Guarantee, unless otherwise specified;

         (f)    a term defined in the Trust Indenture Act has the same meaning
when used in this Series B Capital Securities Guarantee, unless otherwise
defined in this Series B Capital Securities Guarantee or unless the context
otherwise requires; and

         (g)    a reference to the singular includes the plural and vice versa.

         "AFFILIATE" has the same meaning as given to that term in Rule 405
under the Securities Act of 1933, as amended, or any successor rule thereunder.

         "BUSINESS DAY" shall mean any day other than a Saturday, a Sunday or a
day on which banking institutions in New York, New York, Wilmington, Delaware or
Bowling Green, Ohio are authorized or required by law or executive order to
remain closed.

         "CAPITAL SECURITIES GUARANTEE TRUSTEE" shall mean Wilmington Trust
Company, as Trustee under the Series B Capital Securities Guarantee, until a
Successor Capital Securities Guarantee Trustee has been appointed and has
accepted such appointment pursuant to the terms of this Series B Capital
Securities Guarantee and thereafter each such Successor Capital Securities
Guarantee Trustee.

         "COMMON SECURITIES" shall mean the securities representing common
undivided beneficial interest in the assets of the Issuer.

         "CORPORATE TRUST OFFICE" shall mean the office of the Capital
Securities Guarantee Trustee at which the corporate trust business of the
Capital Securities Guarantee Trustee shall, at any particular time, be
principally administered, which office at the date of execution of this
Agreement is located at Rodney Square North, 1100 North Market Street,
Wilmington, Delaware 19890-0001, Attention: Corporate Trust Administration.

         "COVERED PERSON" shall mean any Holder or beneficial owner of Series B
Capital Securities.

         "DEBENTURES" shall mean the series of subordinated debt securities of
the Guarantor designated the 9.34% Junior Subordinated Deferrable Interest
Debentures due May 1, 2030 Series B, held by the Property Trustee (as defined in
the Declaration) of the Issuer.

         "EVENT OF DEFAULT" shall mean a default by the Guarantor on any of its
payment or other obligations under this Series B Capital Securities Guarantee;
provided, however, that, except with respect to default in respect of any
Guarantee Payment, no default by the Guarantor



                                      -3-
<PAGE>   8


hereunder shall constitute an Event of Default unless the Guarantor shall have
received written notice of the default and shall not have cured such default
within 60 days after receipt thereof.

         "GUARANTEE PAYMENTS" shall mean the following payments or
distributions, without duplication, with respect to the Series B Capital
Securities, to the extent not paid or made by or on behalf of the Issuer; (i)
any accumulated and unpaid Distributions (as defined in the Declaration) that
are required to be paid on such Series B Capital Securities, to the extent the
Issuer has funds legally available therefor at such time, (ii) the redemption
price, including all accumulated and unpaid Distributions to the date of
redemption (the "Redemption Price"), to the extent the issuer has funds legally
available therefor at such time, with respect to any Series B Capital Securities
called for redemption, and (iii) upon a voluntary or involuntary dissolution,
winding up or liquidation of the Issuer (other than in connection with the
distribution of Debentures to the Holders in exchange for Series B Capital
Securities or in connection with the redemption of the Series B Capital
Securities, in each case as provided in the Declaration), the lesser of (a) the
aggregate of the liquidation amount and all accumulated and unpaid Distributions
on the Series B Capital Securities to the date of payment, to the extent the
Issuer has funds legally available therefor at such time, and (b) the amount of
assets of the Issuer remaining available for distribution to Holders after
satisfaction of liabilities to creditors of the Issuer as required by applicable
law (in either case, the "Liquidation Distribution"). If an Event of Default has
occurred and is continuing, no Guarantee Payments under the Common Securities
Guarantee with respect to the Common Securities or any guarantee payment under
the Common Securities Guarantee or any Other Common Securities Guarantee shall
be made until the Holders of the Series B Capital Securities shall be paid in
full the Guarantee Payments to which they are entitled under this Series B
Capital Securities Guarantee.

         "HOLDER" shall mean any holder, as registered on the books and records
of the Issuer, of any Series B Capital Securities; provided, however, that, in
determining whether the holders of the requisite percentage of Series B Capital
Securities have given any request, notice, consent or waiver hereunder, "Holder"
shall not include the Guarantor or any Person actually known to a Responsible
Officer of the Capital Securities Guarantee Trustee to be an Affiliate of the
Guarantor.

         "INDEMNIFIED PERSON" shall mean the Capital Securities Guarantee
Trustee (including in its individual capacity), any Affiliate of the Capital
Securities Guarantee Trustee, or any officers, directors, shareholders, members,
partners, employees, representatives, nominees, custodians or agents of the
Capital Securities Guarantee Trustee.

         "INDENTURE" shall mean the Indenture, dated as of March 31, 2000,
between Astoria Financial Corporation, as issuer of Debentures (the "Debenture
Issuer"), and Wilmington Trust Company, as trustee, pursuant to which the
Debentures are to be issued to the Property Trustee of the Issuer.

         "MAJORITY IN LIQUIDATION AMOUNT OF THE SERIES B CAPITAL SECURITIES"
shall mean, except as provided by the Trust Indenture Act, a vote by Holder(s)
of the Series B Capital Securities, voting separately as a class, of more than
50% of the aggregate liquidation amount (including the amount that would be paid
on redemption, liquidation or otherwise, plus accumulated and unpaid



                                      -4-
<PAGE>   9


Distributions to the date upon which the voting percentages are determined) of
all outstanding Series B Capital Securities, excluding Series B Capital
Securities held by the Guarantor and the issuer and any Affiliate thereof.

         "OFFICER'S CERTIFICATE" shall mean, with respect to any Person, a
certificate signed by the Chairman, the Chief Executive Officer, the President,
an Executive or Senior Vice President, the Chief Financial Officer and the
Secretary or an Assistant Secretary. Any Officers' Certificate delivered with
respect to compliance with a condition or covenant provided for in this Series B
Capital Securities Guarantee shall include:

          (a)  a statement that each officer signing the Officers' Certificate
               has read the covenants or conditions and the definitions relating
               thereto;

          (b)  a statement that each such officer has made such examination or
               investigation as, in such officer's opinion, is necessary to
               enable such officer to express an informed opinion as to whether
               or not such covenant or condition has been complied with; and

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

         "OTHER COMMON SECURITIES GUARANTEES" shall have the same meaning as
"Other Guarantees" in the Common Securities Guarantee.

         "OTHER DEBENTURES" shall mean all junior subordinated debentures, other
than the Series A Junior Subordinated Debentures and the Debentures, issued by
the Guarantor, from time to time and sold to trusts other than the Issuer to be
established by the Guarantor (if any), in each case similar to the Issuer.

         "OTHER GUARANTEES" shall mean all guarantees, other than this Series B
Capital Securities Guarantee and the Series A Capital Securities Guarantee, to
be issued by the Guarantor with respect to capital securities (if any) similar
to the Series B Capital Securities, issued by trusts other than the Issuer to be
established by the Guarantor (if any), in each case similar to the Issuer.

         "PERSON" shall mean a legal person, including any individual,
corporation, estate, partnership, joint venture, association, joint stock
company, limited liability company, trust, unincorporated association, or
government or any agent or political subdivision thereof, or any other entity of
whatever nature.

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



                                      -5-
<PAGE>   10


         "RESPONSIBLE OFFICER" shall mean, with respect to a Person, any officer
with direct responsibility for the administration of any matters relating to
this Series B Capital Securities Guarantee.

         "SUCCESSOR CAPITAL SECURITIES GUARANTEE TRUSTEE" shall mean a successor
Capital Securities Guarantee Trustee possessing the qualifications to act as
Capital Securities Guarantee Trustee under Section 4.1.

         "TRUST INDENTURE ACT" shall mean the Trust Indenture Act of 1939, as
amended.

         "TRUST SECURITIES" shall mean the Common Securities and the Series A
Capital Securities and the Series B Capital Securities, collectively.


                                   ARTICLE II
                               TRUST INDENTURE ACT

         SECTION 2.1    TRUST INDENTURE ACT; APPLICATION.

         (a)    This Series B Capital Securities Guarantee is subject to the
provisions of the Trust Indenture Act that are required to be part of this
Series B Capital Securities Guarantee and shall, to the extent applicable, be
governed by such provisions.

         (b)    If and to the extent that any provision of this Series B Capital
Securities Guarantee limits, qualifies, or conflicts with the duties imposed by
Section 310 to 317, inclusive, of the Trust Indenture Act, such imposed duties
shall control. If any provision of this Series B Capital Securities Guarantee
modifies or excludes any provision of the Trust Indenture Act that may be so
modified or excluded, the modified or excluded provision of the Trust Indenture
Act shall be deemed to apply to this Series B Capital Securities Guarantee as so
modified or excluded, as the case may be.

         SECTION 2.2    LISTS OF HOLDERS OF SECURITIES.

         (a)    The Guarantor shall provide the Capital Securities Guarantee
Trustee (unless the Capital Securities Guarantee Trustee is otherwise the
registrar of the Series B Capital Securities) with a list, in such form as the
Capital Securities Guarantee Trustee may reasonably require, of the names and
addresses of the Holders of the Series B Capital Securities ("List of Holders")
as of such date, (i) within fourteen (14) days after each record date for
payment of Distributions (as defined in the Declaration), and (ii) at any other
time within 30 days of receipt by the Guarantor of a written request for a List
of Holders as of a date no more than 14 days before such List of Holders is
given to the Capital Securities Guarantee Trustee; provided, however, that the
Guarantor shall not be obligated to provide such List of Holders given to the
Capital Securities Guarantee Trustee by the Guarantor. The Capital Securities
Guarantee Trustee may destroy any List of Holders previously given to it upon
receipt of a new List of Holders.



                                      -6-
<PAGE>   11


         (b)    The Capital Securities Guarantee Trustee shall comply with its
obligations under Sections 311(a), 311(b) and Section 312(b) of the Trust
Indenture Act.

         SECTION 2.3    REPORTS BY THE CAPITAL SECURITIES GUARANTEE TRUSTEE.
Within 60 days after the date hereof, and no later than the anniversary date
hereof in each succeeding year, the Capital Securities Guarantee Trustee shall
provide to the Holders of the Series B Capital Securities such reports as are
required by Section 313 of the Trust Indenture Act, if any, in the form and in
the manner provided by Section 313 of the Trust Indenture Act. The Capital
Securities Guarantee Trustee shall also comply with the requirements of Section
313(d) of the Trust Indenture Act.

         SECTION 2.4    PERIODIC REPORTS. The Guarantor shall provide to the
Capital Securities Guarantee Trustee such documents, reports and information as
are required by Section 314 (if any) and the compliance certificate required by
Section 314 of the Trust Indenture Act in the form, in the manner and at the
times required by Section 314 of the Trust Indenture Act. Delivery of such
reports, information and documents to the Capital Securities Guarantee Trustee
is for informational purposes only and the Capital Securities Guarantee
Trustee's receipt of such shall not constitute constructive notice of any
information contained herein or determinable from information contained herein,
including the Guarantor's compliance with any of its covenants hereunder (as to
which the Capital Securities Guarantee Trustee is entitled to rely exclusively
on Officers' Certificates).

         SECTION 2.5    EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT. The
Guarantor shall provide to the Capital Securities Guarantee Trustee such
evidence of compliance with the conditions precedent, if any, provided for in
this Series B Capital Securities Guarantee that relate to any of the matters set
forth in Section 314(c) of the Trust Indenture Act. Any certificate or opinion
required to be given by an officer pursuant to Section 314(c)(1) may be given in
the form of an Officers' Certificate.

         SECTION 2.6    WAIVER OF EVENTS OF DEFAULT. The Holders of a Majority
in Liquidation Amount of the Series B Capital Securities may, by vote, on behalf
of the Holders of all of the Series B Capital Securities, waive any past Event
of Default and its consequences. Upon such waiver, any such Event of Default
shall cease to exist, and any Event of Default arising therefrom shall be deemed
to have been cured, for every purpose of this Series B Capital Securities
Guarantee, but no such waiver shall extend to any subsequent or other default of
Event of Default or impair any right consequent thereon.

         SECTION 2.7    NOTICE OF EVENTS OF DEFAULT.

         (a)    The Capital Securities Guarantee Trustee shall, within 10
Business Days after the occurrence of an Event of Default with respect to this
Series B Capital Securities Guarantee actually known to a Responsible Officer of
the Capital Securities Guarantee Trustee, transmit by mail, first class postage
prepaid, to all Holders of the Series B Capital Securities, notices of all such
Events of Default, unless such Events of Default have been cured before the
giving of such notice; provided, however, that except in the case of an Event of
Default arising from the non-payment of any Guarantee Payment, the Capital
Securities Guarantee Trustee shall be protected



                                      -7-
<PAGE>   12


in withholding such notice if and so long as a Responsible Officer of the
Capital Securities Guarantee Trustee in good faith determines that the
withholding of such notice is in the interests of the Holders of the Series B
Capital Securities.

         (b)    The Capital Securities Guarantee Trustee shall not be deemed to
have knowledge of any Event of Default unless the Capital Securities Guarantee
Trustee shall have received written notice, or a Responsible Officer of the
Capital Securities Guarantee Trustee charged with the administration of the
Declaration shall have obtained actual knowledge, of such Event of Default.

         SECTION 2.8    CONFLICTING INTERESTS. The Declaration shall be deemed
to be specifically described in this Series B Capital Securities Guarantee for
the purposes of clause (i) of the first proviso contained in Section 310(b) of
the Trust Indenture Act.


                                   ARTICLE III
                 POWERS, DUTIES AND RIGHTS OF CAPITAL SECURITIES
                                GUARANTEE TRUSTEE

         SECTION 3.1    POWERS AND DUTIES OF THE CAPITAL SECURITIES GUARANTEE
                        TRUSTEE.

         (a)    This Series B Capital Securities Guarantee shall be held by the
Capital Securities Guarantee Trustee for the benefit of the Holders of the
Series B Capital Securities, and the Capital Securities Guarantee Trustee shall
not transfer this Series B Capital Securities Guarantee to any Person except a
Holder of the Series B Capital Securities exercising his or her rights pursuant
to Section 5.4(b) or to a Successor Capital Securities Guarantee Trustee on
acceptance by such Successor Capital Securities Guarantee Trustee of its
appointment to act as Successor Capital Securities Guarantee Trustee. The right,
title and interest of the Capital Securities Guarantee Trustee shall
automatically vest in any Successor Capital Securities Guarantee Trustee, and
such vesting and succession of title shall be effective whether or not
conveyancing documents have been executed and delivered pursuant to the
appointment of such Successor Capital Securities Guarantee Trustee.

         (b)    If an Event of Default actually known to a Responsible Officer
of the Capital Securities Guarantee Trustee has occurred and is continuing, the
Capital Securities Guarantee Trustee shall enforce this Series B Capital
Securities Guarantee for the benefit of the Holders of the Series B Capital
Securities.

         (c)    The Capital Securities Guarantee Trustee, before the occurrence
of any Event of Default (of which, other than a default in respect of any
Guarantee Payment, a Responsible Officer of the Property Trustee has actual
knowledge) and after the curing of all such Events of Default that may have
occurred, shall undertake to perform only such duties as are specifically set
forth in this Series B Capital Securities Guarantee, and no implied covenants or
obligations shall be read into this Series B Capital Securities Guarantee
against the Capital Securities Guarantee Trustee. In case an Event of Default
has occurred (that has not been cured or waived



                                      -8-
<PAGE>   13


pursuant to Section 2.6) and is actually known to a Responsible Officer of the
Capital Securities Guarantee Trustee, the Capital Securities Guarantee Trustee
shall exercise such of the rights and powers vested in it by this Series B
Capital Securities Guarantee, and use the same degree of care and skill in its
exercise thereof, as a prudent person would exercise or use under the
circumstances in the conduct of his or her own affairs.

         (d)    No provision of this Series B Capital Securities Guarantee shall
be construed to relieve the Capital Securities Guarantee Trustee from liability
for its own negligent action, its own negligent failure to act, or its own
willful misconduct, except that:

                (i)     prior to the occurrence of any Event of Default (of
         which, other than a default in respect of any Guarantee Payment, a
         Responsible Officer of the Property Trustee has actual knowledge) and
         after the curing or waiving of all such Events of Default that may have
         occurred:

                        (A)     the duties and obligations of the Capital
                  Securities Guarantee Trustee shall be determined solely by the
                  express provisions of this Series B Capital Securities
                  Guarantee, and the Capital Securities Guarantee Trustee shall
                  not be liable except for the performance of such duties and
                  obligations as are specifically set forth in this Series B
                  Capital Securities Guarantee, and no implied covenants or
                  obligations shall be read into this Series B Capital
                  Securities Guarantee against the Capital Securities Guarantee
                  Trustee; and

                         (B)    in the absence of bad faith on the part of
                  the Capital Securities Guarantee Trustee, the Capital
                  Securities Guarantee Trustee may conclusively rely, as to the
                  truth of the statements and the correctness of the opinions
                  expressed therein, upon any certificates or opinions furnished
                  to the Capital Securities Guarantee Trustee and conforming to
                  the requirements of this Series B Capital Securities
                  Guarantee; provided, however, that in the case of any such
                  certificates or opinions that by any provision hereof are
                  specifically required to be furnished to the Capital
                  Securities Guarantee Trustee, the Capital Securities Guarantee
                  Trustee shall be under a duty to examine the same to determine
                  whether or not on their face they conform to the requirements
                  of this Series B Capital Securities Guarantee;

                (ii)    the Capital Securities Guarantee Trustee shall not be
         liable for any errors of judgment made in good faith by a Responsible
         Officer of the Capital Securities Guarantee Trustee, unless it shall be
         proved that the Capital Securities Guarantee Trustee or such
         Responsible Officer was negligent in ascertaining the pertinent facts
         upon which such judgment was made;

                (iii)   the Capital Securities Guarantee Trustee shall not be
         liable with respect to any actions taken or omitted to be taken by it
         in good faith in accordance with the direction of the Holders of a
         Majority in Liquidation Amount of the Series B Capital Securities
         relating to the time, method and place of conducting any proceeding for
         any remedy available to the Capital Securities Guarantee Trustee, or
         exercising any trust or



                                      -9-
<PAGE>   14


         power conferred upon the Capital Securities Guarantee Trustee under
         this Series B Capital Securities Guarantee; and

                (iv)    no provision of this Series B Capital Securities
         Guarantee shall require the Capital Securities Guarantee 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 the Capital Securities Guarantee
         Trustee shall have reasonable grounds for believing that the repayment
         of such funds or liability is not reasonably assured to it under the
         terms of this Series B Capital Securities Guarantee or indemnity,
         reasonably satisfactory to the Capital Securities Guarantee Trustee,
         against such risk or liability is not reasonably assured to it.

         SECTION 3.2    CERTAIN RIGHTS OF CAPITAL SECURITIES GUARANTEE TRUSTEE.

         (a)    Subject to the provisions of Section 3.1:

                (i)     the Capital Securities Guarantee Trustee may
         conclusively rely, and shall be fully protected in acting or refraining
         from acting, upon any resolution, certificate, statement, instrument,
         opinion, report, notice, request, direction, consent, order, bond,
         debentures, note, other evidence of indebtedness or other paper or
         document believed by it to be genuine and to have been signed, sent or
         presented by the proper party or parties;

                (ii)    any direction or act of the Guarantor contemplated by
         this Series B Capital Securities Guarantee may be sufficiently
         evidenced by an Officers' Certificate;

                (iii)   whenever, in the administration of this Series B Capital
         Securities Guarantee, the Capital Securities Guarantee Trustee shall
         deem it desirable that a matter be proved or established before taking,
         suffering or omitting any action hereunder, the Capital Securities
         Guarantee Trustee (unless other evidence is herein specifically
         prescribed) may, in the absence of bad faith on its part, request and
         conclusively rely upon an Officers' Certificate, which, upon receipt of
         such request, shall be promptly delivered by the Guarantor;

                (iv)    The Capital Securities Guarantee Trustee shall have no
         duty to see to any recording, filing or registration of any instrument
         or other document (or any recording, refiling or registration thereof);

                (v)     the Capital Securities Guarantee Trustee may consult
         with counsel of its selection, and the advice or opinion of such
         counsel with respect to legal matters shall be full and complete
         authorization and protection in respect of any action taken, suffered
         or omitted by it hereunder in good faith and in accordance with such
         advice or opinion; such counsel may be counsel to the Guarantor or any
         of its Affiliates and may include any of its employees; and the Capital
         Securities Guarantee Trustee shall have the right at any time to seek
         instructions concerning the administration of this Series B Capital
         Securities Guarantee from any court of competent jurisdiction;



                                      -10-
<PAGE>   15


                (vi)    the Capital Securities Guarantee Trustee shall be under
         no obligation to exercise any of the rights or powers vested in it by
         this Series B Capital Securities Guarantee at the request or direction
         of any Holder, unless such Holder shall have provided to the Capital
         Securities Guarantee Trustee such security and indemnity, reasonably
         satisfactory to the Capital Securities Guarantee Trustee, against the
         costs, expenses (including attorneys' fees and expenses and the
         expenses of the Capital Securities Guarantee Trustee's agents, nominees
         or custodians) and liabilities that might be incurred by it in
         complying with such request or direction, including such reasonable
         advances as may be requested by the Capital Securities Guarantee
         Trustee, provided, however, that nothing contained in this Section
         3.2(a)(vi) shall be taken to relieve the Capital Securities Guarantee
         Trustee, upon the occurrence of an Event of Default, of its obligation
         to exercise the rights and powers vested in it by this Series B Capital
         Securities Guarantee;

                (vii)   the Capital Securities Guarantee Trustee shall have no
         obligation to make any investigation into the facts or matters stated
         in any resolution, certificate, statement, instrument, opinion, report,
         notice, request, direction, consent, order, bond, debentures, note,
         other evidence of indebtedness or other paper or document, but the
         Capital Securities Guarantee Trustee, in its discretion, may make such
         further inquiry or investigation into such facts or matters as it may
         see fit;

                (viii)  the Capital Securities Guarantee Trustee may execute
         any of the trusts or powers hereunder or perform any duties hereunder
         either directly or by or through agents, nominees, custodians or
         attorneys, and the Capital Securities Guarantee Trustee shall not be
         responsible for any misconduct or negligence on the part of any such
         person appointed with due care by it hereunder;

                (ix)    any action taken by the Capital Securities
         Guarantee Trustee or its agents hereunder shall bind the Holders of the
         Series B Capital Securities, and the signature of the Capital
         Securities Guarantee Trustee or its agents alone shall be sufficient
         and effective to perform any such action; and no third party shall be
         required to inquire as to the authority of the Capital Securities
         Guarantee Trustee to so act or as to its compliance with any of the
         terms and provisions of this Series B Capital Securities Guarantee,
         both of which shall be conclusively evidenced by this Capital
         Securities Guarantee Trustee's or its agent's taking such action;

                (x)     whenever in the administration of this Series B Capital
         Securities Guarantee the Capital Securities Guarantee Trustee shall
         deem it desirable to receive instructions with respect to enforcing any
         remedy or right or taking any action hereunder, the Capital Securities
         Guarantee Trustee (a) may request instructions from the Holders of a
         Majority in Liquidation Amount of the Series B Capital Securities, (b)
         may refrain from enforcing such remedy or right or taking such other
         action until such instructions are received, and (c) shall be protected
         in conclusively relying on or acting in accordance with such
         instructions; and



                                      -11-
<PAGE>   16


                (xi)    the Capital Securities Guarantee Trustee shall not
         be liable for any action taken, suffered, or omitted to be taken by it
         in good faith, without negligence, and reasonably believed by it to be
         authorized or within the discretion or rights or powers conferred upon
         it by this Series B Capital Securities Guarantee.

         (b)    No provision of this Series B Capital Securities Guarantee
shall be deemed to impose any duty or obligation on the Capital Securities
Guarantee Trustee to perform any act or acts or exercise any right, power, duty
or obligation conferred or imposed on it in any jurisdiction in which it shall
be illegal, or in which the Capital Securities Guarantee Trustee shall be
unqualified or incompetent in accordance with applicable law, to perform any
such act or acts or to exercise any such right, power, duty or obligation. No
permissive power or authority available to the Capital Securities Guarantee
Trustee shall be construed to be a duty.

         SECTION 3.3    NOT RESPONSIBLE FOR RECITALS OR ISSUANCE OF SERIES B
CAPITAL SECURITIES GUARANTEE. The recitals contained in this Series B Capital
Securities Guarantee shall be taken as the statements of the Guarantor, and the
Capital Securities Guarantee Trustee does not assume any responsibility for
their correctness. The Capital Securities Guarantee Trustee makes no
representation as to the validity or sufficiency of this Series B Capital
Securities Guarantee.


                                   ARTICLE IV
                      CAPITAL SECURITIES GUARANTEE TRUSTEE

         SECTION 4.1    CAPITAL SECURITIES GUARANTEE TRUSTEE; ELIGIBILITY.

         (a)    There shall at all times be a Capital Securities Guarantee
Trustee that shall:

                (i)     not be an Affiliate of the Guarantor; and

                (ii)    be a corporation or other 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 by the Securities and Exchange Commission to act
         as an indenture trustee under the Trust Indenture Act, 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; it being understood that if such
         corporation or other Person publishes reports of condition at least
         annually, pursuant to law or to the requirements of the supervising or
         examining authority referred to above, then, for the purposes of this
         Section 4.1(a)(ii) and to the extent permitted by the Trust Indenture
         Act, the combined capital and surplus of such corporation shall be
         deemed to be its combined capital and surplus as set forth in its most
         recent report of condition so published.

         (b)    If at any time the Capital Securities Guarantee Trustee shall
cease to be eligible to so act under Section 4.1(a), the Capital Securities
Guarantee Trustee shall immediately resign in the manner and with the effect set
out in Section 4.2(c).



                                      -12-
<PAGE>   17


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

         SECTION 4.2    APPOINTMENT, REMOVAL AND RESIGNATION OF COMMON
                        SECURITIES GUARANTEE TRUSTEE.

         (a)    Subject to Section 4.2(b), the Capital Securities Guarantee
Trustee may be appointed or removed without cause at any time by the Guarantor
except during an Event of Default.

         (b)    The Capital Securities Guarantee Trustee shall not be removed in
accordance with Section 4.2(a) until a Successor Capital Securities Guarantee
Trustee has been appointed and has accepted such appointment by written
instrument executed by such Successor Capital Securities Guarantee Trustee and
delivered to the Guarantor.

         (c)    The Capital Securities Guarantee Trustee shall hold office until
a Successor Capital Securities Guarantee Trustee shall have been appointed,
subject to Section 4.1, or until its removal or resignation. The Capital
Securities Guarantee Trustee may resign from office (without need for prior or
subsequent accounting) by an instrument in writing executed by the Capital
Securities Guarantee Trustee and delivered to the Guarantor, which resignation
shall not take effect until a Successor Capital Securities Guarantee Trustee has
been appointed, subject to Section 4.1, and has accepted such appointment by
instrument in writing executed by such Successor Capital Securities Guarantee
Trustee and delivered to the Guarantor and the resigning Capital Securities
Guarantee Trustee.

         (d)    If no Successor Capital Securities Guarantee Trustee shall have
been appointed and accepted appointment as provided in this Section 4.2 within
60 days after delivery of an instrument of removal or resignation, the Capital
Securities Guarantee Trustee resigning or being removed may petition any court
of competent jurisdiction for appointment of a Successor Capital Securities
Guarantee Trustee. Such court may thereupon, after prescribing such notice, if
any, as it may deem proper, appoint a Successor Capital Securities Guarantee
Trustee.

         (e)    No Capital Securities Guarantee Trustee shall be liable for the
acts or omissions to act of any Successor Capital Securities Guarantee Trustee.

         (f)    Upon termination of this Series B Capital Securities Guarantee
or removal or resignation of the Capital Securities Guarantee Trustee pursuant
to this Section 4.2, the Guarantor shall pay to the Capital Securities Guarantee
Trustee all amounts due to the Capital Securities Guarantee Trustee accrued to
the date of such termination, removal or resignation.



                                      -13-
<PAGE>   18


                                    ARTICLE V
                                    GUARANTEE

         SECTION 5.1    GUARANTEE. The Guarantor irrevocably and unconditionally
agrees to pay in full to the Holders the Guarantee Payments (without duplication
of amounts theretofore paid by the Issuer), as and when due, regardless of any
defense, right of set-off or counterclaim that the Issuer may have or assert.
The Guarantor's obligation to make a Guarantee Payment may be satisfied by the
direct payment of the required amounts by the Guarantor to the Holders or by
causing the Issuer to pay such amounts to the Holders.

         SECTION 5.2    WAIVER OF NOTICE AND DEMAND. The Guarantor hereby waives
notice of acceptance on this Series B Capital Securities Guarantee and of any
liability to which it applies or may apply, presentment, demand for payment, any
right to require a proceeding first against the Issuer or any other Person
before proceeding against the Guarantor, protest, notice of nonpayment, notice
of dishonor, notice of redemption and all other notices and demands.

         SECTION 5.3    OBLIGATIONS NOT AFFECTED. The obligations, covenants,
agreements and duties of the Guarantor under this Series B Capital Securities
Guarantee shall in no way be affected or impaired by reason of the happening
from time to time of any of the following:

         (a)    The release or waiver, by operation of law or otherwise, of the
performance or observance by the Issuer or any express or implied agreement,
covenant, term or condition relating to the Series B Capital Securities to be
performed or observed by the Issuer;

         (b)    the extension of time for the payment by the Issuer of all or
any portion of the Distributions, Redemption Price, Liquidation Distribution or
any other sums payable under the terms of the Series B Capital Securities or the
extension of time for the performance of any other obligation under, arising out
of, or in connection with, the Series B Capital Securities;

         (c)    any failure, omission, delay or lack of diligence on the part of
the Holders to enforce, assert or exercise any right, privilege, power of remedy
conferred on the Holders pursuant to the terms of the Series B Capital
Securities, or any action on the part of the Issuer granting indulgence or
extension of any kind;

         (d)    the voluntary or involuntary liquidation, dissolution, sale of
any collateral, receivership, insolvency, bankruptcy, assignment for the benefit
of creditors, reorganization, arrangement, composition or readjustment of debt
of, or other similar proceedings affecting, the Issuer or any of the assets of
the Issuer;

         (e)    any invalidity of, or defect or deficiency in, the Series B
Capital Securities;

         (f)    the settlement or compromise of any obligation guaranteed hereby
or hereby incurred;

         (g)    the consummation of the Exchange Offer; or



                                      -14-
<PAGE>   19


         (h)    any other circumstance whatsoever that might otherwise
constitute a legal or equitable discharge or defense of a guarantor;

it being the intent of this Section 5.3 that the obligations of the Guarantor
with respect to the Guarantee Payments shall be absolute and unconditional under
any and all circumstances.

         There shall be no obligations of the Holders to give notice to, or
obtain consent of, the Guarantor with respect to the happening of any of the
foregoing.

         SECTION 5.4    RIGHTS OF HOLDERS.

         (a)    The Holders of a Majority in Liquidation Amount of the Series B
Capital Securities have the right to direct the time, method and place of
conducting any proceeding for any remedy available to the Capital Securities
Guarantee Trustee in respect of this Series B Capital Securities Guarantee or
exercising any trust or power conferred upon the Capital Securities Guarantee
Trustee under this Series B Capital Securities Guarantee.

         (b)    If the Capital Securities Guarantee Trustee fails to enforce
this Series B Capital Securities Guarantee, any Holder of this Series B Capital
Securities may institute a legal proceeding directly against the Guarantor to
enforce the Capital Securities Guarantee Trustee's rights under this Series B
Capital Securities Guarantee, without first instituting a legal proceeding
against the Issuer, the Capital Securities Guarantee Trustee or any other person
or entity. The Guarantor waives any right or remedy to require that any action
be brought first against the Issuer or any other person or entity before
proceeding directly against the Guarantor.

         SECTION 5.5    GUARANTEE OF PAYMENT. This Series B Capital Securities
Guarantee creates a guarantee of payment and not of
collection.

         SECTION 5.6    SUBROGATION. The Guarantor shall be subrogated to all
(if any) rights of the Holders of Series B Capital Securities against the Issuer
in respect of any amounts paid to such Holders by the Guarantor under this
Series B Capital Securities Guarantee; provided, however, that the Guarantor
shall not (except to the extent required by mandatory provisions of law) be
entitled to enforce or exercise any right that it may acquire by way of
subrogation or any indemnity, reimbursement or other agreement, in all cases as
a result of payment under this Series B Capital Securities Guarantee, if, at the
time of any such payment, any amounts are due and unpaid under this Series B
Capital Securities Guarantee. If any amount shall be paid to the Guarantor in
violation of the preceding sentence, the Guarantor agrees to hold such amount in
trust for the Holders and to pay over such amount to the Holders.

         SECTION 5.7    INDEPENDENT OBLIGATIONS. The Guarantor acknowledges that
its obligations hereunder are independent of the obligations of the Issuer with
respect to the Series B Capital Securities, and that the Guarantor shall be
liable as principal and as debtor hereunder to make Guarantee Payments pursuant
to the terms of this Series B Capital Securities Guarantee notwithstanding the
occurrence of any event referred to in subsections (a) through (h), inclusive,
of Section 5.3 hereof.



                                      -15-
<PAGE>   20


                                   ARTICLE VI
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

         SECTION 6.1    LIMITATION OF TRANSACTIONS. So long as any Capital
Securities remain outstanding, the Guarantor shall 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 Guarantor'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 of the Guarantor (including Other
Debentures) that rank pari passu with or junior in right of payment to the
Debentures or (iii) make any guarantee payments with respect to any guarantee by
the Guarantor of the debt securities of any subsidiary of the Guarantor
(including Other Guarantees) if such guarantee ranks pari passu with or junior
in right of payment to the Debentures (other than (a) dividends or distributions
in shares of, or options, warrants, right to subscribe for or purchase shares
of, common stock of the Guarantor, (b) any declaration of a dividend in
connection with the implementation of a shareholders' 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 this Series B
Capital Securities Guarantee and the Series A Capital Securities Guarantee, (d)
as a result of a reclassification of the Guarantor's capital stock or the
exchange or the conversion of one class or series of the Guarantor's capital
stock for another class or series of the Guarantor's capital stock, (e) the
purchase of fractional interests in shares of the Guarantor'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 Guarantor's benefit
or compensation plans for its directors, officers or employees or any of the
Guarantor's dividend reinvestment plans) if at such time (1) there shall have
occurred any event of which the Guarantor has actual knowledge that (A) is a
Default or Event of Default (each as defined in the Indenture) and (B) in
respect of which the Guarantor shall not have taken reasonable steps to cure,
(2) if the Debentures are held by the Property Trustee, the Guarantor shall be
in default with respect to its payment of any obligations under this Series B
Capital Securities Guarantee or (3) the Guarantor shall have given notice of its
election of the exercise of its right to commence an Extended Interest Payment
Period as provided in the Indenture and shall not have rescinded such notice,
and such Extended Interest Payment Period, or an extension thereof, shall have
commenced and be continuing.

         SECTION 6.2    RANKING. This Series B Capital Securities Guarantee will
constitute an unsecured obligation of the Guarantor and will rank (i)
subordinate and junior in right of payment to all Allocable Amounts (as defined
in the Indenture) in respect of Senior Indebtedness (as defined in the
Indenture), to the same extent and in the same manner that the Debentures are
subordinated to Senior Indebtedness pursuant to the Indenture, it being
understood that the terms of Article XV of the Indenture shall apply to the
obligations of the Guarantor under this Series B Capital Securities Guarantee as
if such Article XV were set forth herein in full, (ii) pari passu with the most
senior preferred or preference stock now or hereafter issued by the Guarantor
and with the Series A Capital Securities Guarantee, any Other Guarantee and,
except to the extent set forth therein, the Common Securities Guarantee, any
Other Common Securities Guarantee, and any guarantee now or hereafter entered
into by the Guarantor in respect of any preferred or preference stock of any
Affiliate of the Guarantor, and (iii) senior to the Guarantor's common stock.



                                      -16-
<PAGE>   21


                                   ARTICLE VII
                                   TERMINATION

         SECTION 7.1    TERMINATION. This Series B Capital Securities Guarantee
shall terminate and be of no further force and effect upon (i) full payment of
the Redemption Price of all Series B Capital Securities, (ii) dissolution,
winding up or liquidation of the Issuer, immediately following the full payment
of the amounts payable in accordance with the Declaration or (iii) the
distribution of all of the Debentures to the Holders of the Trust Securities.
Notwithstanding the foregoing, this Series B Capital Securities Guarantee will
continue to be effective or will be reinstated, as the case may be, if at any
time any Holder of the Series B Capital Securities must restore payment of any
sums paid under the Series B Capital Securities or under this Series B Capital
Securities Guarantee.


                                  ARTICLE VIII
                                 INDEMNIFICATION

         SECTION 8.1    EXCULPATION.

         (a)    No Indemnified Person shall be liable, responsible or
accountable in damages or otherwise to the Guarantor or any Covered Person for
any loss, damage or claim incurred by reason of any act or omission performed or
omitted by such Indemnified Person in good faith in accordance with this Series
B Capital Securities Guarantee and in a manner that such Indemnified Person
reasonably believed to be within the scope of the authority conferred on such
Indemnified Person by this Series B Capital Securities Guarantee or by law,
except that an Indemnified Person shall be liable for any such loss, damage or
claim incurred by reason of such Indemnified Person's negligence or willful
misconduct with respect to such acts or omissions.

         (b)    An Indemnified Person shall be fully protected in relying in
good faith upon the records of the Guarantor and upon such information,
opinions, reports or statements presented to the Guarantor by any Person as to
matters the Indemnified Person reasonably believes are within such other
Person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Guarantor, including information,
opinions, reports or statements as to the value and amount of the assets,
liabilities, profits, losses, or any other facts pertinent to the existence and
amount of assets from which Distributions to Holders of Series B Capital
Securities might properly be paid.

         SECTION 8.2    COMPENSATION AND INDEMNIFICATION. The Guarantor agrees
to pay to the Capital Securities Guarantee Trustee such compensation for its
services as shall be mutually agreed upon by the Guarantor and the Capital
Securities Guarantee Trustee. The Guarantor shall reimburse the Capital
Securities Guarantee Trustee upon request for all reasonable out-of-pocket
expenses incurred by it, including the reasonable compensation and expenses of
the Capital Securities Guarantee Trustee's agents and counsel, except any
expense as may be attributable to the negligence or bad faith of the Capital
Securities Guarantee Trustee.



                                      -17-
<PAGE>   22


         The Guarantor agrees to indemnify each Indemnified Person for, and to
hold each Indemnified Person harmless against, any and all loss, liability,
damage, action, suit, claim or expense incurred without negligence or bad faith
on its part, arising out of or in connection with the acceptance or
administration of the trust or trusts hereunder, including the costs and
expenses (including reasonable legal fees and expenses) of defending itself
against, or investigating, any claim or liability in connection with the
exercise or performance of any of its powers or duties hereunder. The provisions
of this Section 8.2 shall survive the termination of this Series B Capital
Securities Guarantee and shall survive the resignation or removal of the Capital
Securities Guarantee Trustee.


                                   ARTICLE IX
                                  MISCELLANEOUS

         SECTION 9.1    SUCCESSORS AND ASSIGNS. All guarantees and agreements
contained in this Series B Capital Securities Guarantee shall bind the
successors, assigns, receivers, trustees and representatives of the Guarantor
and shall inure to the benefit of the Holders of the Series B Capital Securities
then outstanding. Except in connection with any merger or consolidation of the
Guarantor with or into another entity permitted by Section 10.01 of the
Indenture or any sale, transfer, conveyance or other disposition of the property
of the Guarantor permitted by Section 10.01 of the Indenture, the Guarantor may
not assign its rights or delegate its obligations under this Capital Securities
Guarantee.

         SECTION 9.2    AMENDMENTS. Except with respect to any changes that do
not materially adversely affect the rights of Holders of the Series B Capital
Securities (in which case no consent of such Holders will be required), this
Series B Capital Securities Guarantee may only be amended with the prior
approval of the Holders of a Majority in Liquidation Amount of the Series B
Capital Securities. The provisions of Section 12.2 of the Declaration with
respect to meetings of Holders of the Trust Securities apply to the giving of
such approval. This Series B Capital Securities Guarantee may not be amended,
and no amendment hereof that affects the Capital Securities Guarantee Trustee's
rights, duties or immunities hereunder or otherwise, shall be effective, unless
such amendment is executed by the Capital Securities Guarantee Trustee (which
shall have no obligation to execute any such amendment, but may do so in its
sole discretion).

         SECTION 9.3    NOTICES. All notices provided for in this Series B
Capital Securities Guarantee shall be in writing, dully signed by the party
giving such notice, and shall be delivered, telecopied or mailed by first class
mail, as follows:

         (a)    If given to the issuer, in care of the Administrative Trustee at
the Issuer's mailing address set forth below (or such other address as the
Issuer may give notice of to the Capital Securities Guarantee Trustee and the
Holders of the Series B Capital Securities):



                                      -18-
<PAGE>   23


                  SKY FINANCIAL CAPITAL TRUST I
                  c/o Sky Financial Group, Inc.
                  221 South Church Street
                  Bowling Green, Ohio 43402
                  Attention:  W. Granger Souder, Jr., Esq.
                  Telephone:  (419) 327-6304
                  Telecopier:  (419) 327-6300

         (b)    If given to the Capital Securities Guarantee Trustee, at the
Capital Securities Guarantee Trustee's mailing address set forth below (or such
other address as the Capital Securities Guarantee Trustee may give notice of to
the Holders of the Series B Capital Securities):

                  WILMINGTON TRUST COMPANY
                  Rodney Square North
                  1100 North Market Street
                  Wilmington, Delaware 19890-00001

                  Attention:  Corporate Trust administration
                  Telephone:  (302) 651-1000
                  Telecopier:  (302) 651-8882

         (c)    If given to the Guarantor, at the Guarantor's mailing address
set forth below (or such other address as the Guarantor may give notice of to
the Capital Securities Guarantee Trustee and the Holders of the Series B Capital
Securities):

                  SKY FINANCIAL GROUP, INC.
                  221 South Church Street
                  Bowling Green, Ohio  43402
                  Attention:  W. Granger Souder, Jr., Esq.
                  Telephone:  (419) 327-6304
                  Telecopier:  (419) 327-6300

         (d)    If given to any Holder of the Series B Capital Securities, at
the address set forth on the books and records of the Issuer.

         All such notices shall be deemed to have been given when received in
person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid except that if a notice or other document is refused delivery or
cannot be delivered because of a changed address of which no notice was given,
such notice or other document shall be deemed to have been delivered on the date
of such refusal or inability to deliver.

         SECTION 9.5    GOVERNING LAW. THIS SERIES B CAPITAL SECURITIES
GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO CONFLICT OF LAW
PRINCIPLES THEREOF.



                                      -19-
<PAGE>   24


         This Series B Capital Securities Guarantee is executed as of the day
and year first above written.


                                       SKY FINANCIAL GROUP, INC.,
                                       as Guarantor


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



                                       WILMINGTON TRUST COMPANY,
                                       as Capital Securities Guarantee Trustee



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



                                      -20-