<PAGE>
 
                                                                   EXHIBIT 10.24



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


                SERIES A CAPITAL SECURITIES GUARANTEE AGREEMENT


                      Investors Financial Services Corp.


                         Dated as of January 31, 1997


                     ====================================
<PAGE>
 
                               TABLE OF CONTENTS
                               -----------------

<TABLE> 
<CAPTION> 
                                                                            Page
                                                                            ----

                                   ARTICLE I
                        DEFINITIONS AND INTERPRETATION
     <S>                                                                    <C>
     SECTION 1.1  Definitions and Interpretation............................   2

                                  ARTICLE II
                              TRUST INDENTURE ACT

     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 to Capital Securities Guarantee Trustee..   7
     SECTION 2.5  Evidence of Compliance with Conditions Precedent..........   7
     SECTION 2.6  Events of Default; Waiver.................................   7
     SECTION 2.7  Event of Default; Notice..................................   8
     SECTION 2.8  Conflicting Interests.....................................   8

                                  ARTICLE III
                         POWERS, DUTIES AND RIGHTS OF
                     CAPITAL SECURITIES GUARANTEE TRUSTEE
 
     SECTION 3.1  Powers and Duties of the Capital Securities 
                  Guarantee Trustee.........................................   8
     SECTION 3.2  Certain Rights of Capital Securities Guarantee Trustee....  11
     SECTION 3.3. Not Responsible for Recitals or Issuance of 
                  Series A Capital Securities Guarantee.....................  13

                                  ARTICLE IV
                     CAPITAL SECURITIES GUARANTEE TRUSTEE

     SECTION 4.1  Capital Securities Guarantee Trustee; Eligibility.........  13
     SECTION 4.2  Appointment, Removal and Resignation of Capital 
                  Securities Guarantee Trustee..............................  14

                                   ARTICLE V
                                   GUARANTEE

     SECTION 5.1  Guarantee.................................................  15
     SECTION 5.2  Waiver of Notice and Demand...............................  15
     SECTION 5.3  Obligations Not Affected..................................  15
     SECTION 5.4  Rights of Holders.........................................  17
     SECTION 5.5  Guarantee of Payment......................................  17
     SECTION 5.6  Subrogation...............................................  17
</TABLE>
<PAGE>
 
<TABLE>
<CAPTION> 
                                                                            Page
                                                                            ----
     <S>                                                                    <C>
     SECTION 5.7  Independent Obligations...................................  18

                                  ARTICLE VI
                   LIMITATION OF TRANSACTIONS; SUBORDINATION

     SECTION 6.1  Limitation of Transactions................................  18
     SECTION 6.2  Ranking...................................................  19

                                  ARTICLE VII
                                  TERMINATION

     SECTION 7.1  Termination...............................................  19

                                 ARTICLE VIII

     SECTION 8.1  Compensation and Expenses of Capital Securities
                  Guarantee Trustee.........................................  20

                                  ARTICLE IX
                                INDEMNIFICATION

     SECTION 9.1  Exculpation...............................................  21
     SECTION 9.2  Indemnification...........................................  21

                                   ARTICLE X
                                 MISCELLANEOUS
 
     SECTION 10.1 Successors and Assigns....................................  22
     SECTION 10.2 Amendments................................................  22
     SECTION 10.3 Notices...................................................  22
     SECTION 10.4 Exchange Offer............................................  23
     SECTION 10.5 Benefit...................................................  23
     SECTION 10.6 Governing Law.............................................  24
</TABLE>

                                      ii
<PAGE>
 
                SERIES A CAPITAL SECURITIES GUARANTEE AGREEMENT


          This GUARANTEE AGREEMENT (the "Series A Capital Securities
Guarantee"), dated as of January 31, 1997, is executed and delivered by
Investors Financial Services Corp., a Delaware corporation (the "Guarantor"),
and The Bank of New York, a New York banking corporation, as trustee (the
"Capital Securities Guarantee Trustee"), for the benefit of the Holders (as
defined herein) from time to time of the Series A Capital Securities (as defined
herein) of Investors Capital Trust I, a Delaware statutory business trust (the
"Issuer").

          WHEREAS, pursuant to an Amended and Restated Declaration of Trust
(the "Declaration"), dated as of January 31, 1997, among the trustees of the
Issuer, the Guarantor, as sponsor, and the holders from time to time of
undivided beneficial interests in the assets of the Issuer, the Issuer is
issuing on the date hereof 25,000 capital securities, having an aggregate
liquidation amount of $25,000,000, such capital securities being designated the
9.77% Series A Capital Securities (collectively the "Series A Capital
Securities") and, in connection with an Exchange Offer, if any, (as defined in
the Declaration) has agreed to execute and deliver the 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, as incentive for the Holders to purchase the Series A Capital
Securities, the Guarantor desires irrevocably and unconditionally to agree, to
the extent set forth in this Series A Capital Securities Guarantee, to pay to
the Holders the Guarantee Payments (as defined below).  The Guarantor agrees to
make certain other payments on the terms and conditions set forth herein.

          WHEREAS, the Guarantor is executing and delivering a guarantee
agreement (the "Common Securities Guarantee"), with substantially identical
terms to this Series A Capital Securities Guarantee, for the benefit of the
holders of the Common Securities (as defined herein), except 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 Series A Capital Securities and the Series B Capital Securities, if any, to
receive Guarantee Payments under this Series A Capital Securities Guarantee and
the Series B Capital Securities Guarantee, if any, as the case may be.

          NOW, THEREFORE, in consideration of the purchase by each Holder, which
purchase the Guarantor hereby acknowledges
<PAGE>
 
shall benefit the Guarantor, the Guarantor executes and delivers this Series A
Capital Securities Guarantee for the benefit of the Holders.


                                   ARTICLE I
                        DEFINITIONS AND INTERPRETATION

SECTION 1.1    Definitions and Interpretation
               ------------------------------

          In this Series A Capital Securities Guarantee, unless the context
otherwise requires:

          (a)  Capitalized terms used in this Series A 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 at the date of execution of
               this Series A Capital Securities Guarantee have the same meaning
               when used in this Series A Capital Securities Guarantee unless
               otherwise defined in this Series A Capital Securities Guarantee;

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

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

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

          (f)  a term defined in the Trust Indenture Act has the same meaning
               when used in this Series A Capital Securities Guarantee, unless
               otherwise defined in this Series A 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.

                                       2
<PAGE>
 
          "Business Day" means any day other than a Saturday or a Sunday, or a
           ------------                                                       
day on which banking institutions in The City of New York or Boston,
Massachusetts are authorized or required by law or executive order to close.

          "Capital Securities Guarantee Trustee" means The Bank of New York, a
           ------------------------------------                               
New York banking corporation, until a Successor Capital Securities Guarantee
Trustee has been appointed and has accepted such appointment pursuant to the
terms of this Series A Capital Securities Guarantee and thereafter means each
such Successor Capital Securities Guarantee Trustee.

          "Common Securities" means the securities representing common undivided
           -----------------                                                    
beneficial interests in the assets of the Issuer.

          "Corporate Trust Office" means 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 101 Barclay Street, 21st Floor West, New York, New York 10286.

          "Covered Person" means any Holder or beneficial owner of Series A
           --------------                                                  
Capital Securities.

          "Debentures" means the series of subordinated debt securities of the
           ----------                                                         
Guarantor designated the 9.77% Series A Junior Subordinated Deferrable Interest
Debentures due February 1, 2027 held by the Property Trustee (as defined in the
Declaration) of the Issuer.

          "Event of Default" means a default by the Guarantor on any of its
           ----------------                                                
payment or other obligations under this Series A Capital Securities Guarantee.

          "Guarantee Payments" means the following payments or distributions,
           ------------------                                                
without duplication, with respect to the Series A Capital Securities, to the
extent not paid or made by the Issuer:  (i) any accumulated and unpaid
Distributions (as defined in the Declaration) that are required to be paid on
such Series A Capital Securities to the extent the Issuer has funds on hand
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 on hand legally available
therefor at such time, with respect to any Series A Capital Securities called
for redemption by the Issuer, and (iii) upon a voluntary or involuntary
termination and liquidation of the Issuer (other than in connection with the
distribution of Debentures to the Holders in exchange for Series A Capital
Securities as provided in the Declaration), the lesser of (a) the aggregate of
the liquidation amount and all

                                       3
<PAGE>
 
accumulated and unpaid Distributions on the Series A Capital Securities to the
date of payment, to the extent the Issuer has funds on hand legally available
therefor, and (b) the amount of assets of the Issuer remaining available for
distribution to Holders in liquidation of the Issuer.  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 any Other Common Securities Guarantees shall be made until the
Holders shall be paid in full the Guarantee Payments to which they are entitled
under this Series A Capital Securities Guarantee.

          "Holder" shall mean any holder, as registered on the books and records
           ------                                                               
of the Issuer, of any Series A Capital Securities; provided, however, that, in
determining whether the holders of the requisite percentage of Series A Capital
Securities have given any request, notice, consent or waiver hereunder, "Holder"
shall not include the Guarantor or any Affiliate of the Guarantor.

          "Indemnified Person" means the Capital Securities Guarantee Trustee,
           ------------------                                                 
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" means the Indenture dated as of January 31, 1997, among
           ---------                                                         
the Guarantor (the "Debenture Issuer") and The Bank of New York, 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 A Capital Securities"
           ----------------------------------------------------------------- 
means, except as provided by the Trust Indenture Act, a vote by Holder(s) of
more than 50% of the aggregate liquidation amount (including the stated amount
that would be paid on redemption, liquidation or otherwise, plus accumulated
and unpaid Distributions to the date upon which the voting percentages are
determined) of all Series A Capital Securities.

          "Officers' Certificate" means, with respect to any person, a
           ---------------------                                      
certificate signed by the Chairman, a Vice Chairman, the Chief Executive
Officer, the President, a Vice President, the Comptroller, the Secretary or an
Assistant Secretary of the Guarantor.  Any Officers' Certificate delivered with
respect to compliance with a condition or covenant provided for in this Series A
Capital Securities Guarantee (other than pursuant to Section 314(a)(4) of the
Trust Indenture Act) shall include:

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

                                       4
<PAGE>
 
          (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, 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" means all junior subordinated debentures issued by
           ----------------                                                    
the Guarantor from time to time and sold to trusts to be established by the
Guarantor (if any), in each case similar to the Issuer.

          "Other Guarantees" means all guarantees to be issued by the Guarantor
           ----------------                                                    
with respect to capital securities (if any) similar to the Series A Capital
Securities issued by other trusts to be established by the Guarantor (if any),
in each case similar to the Issuer.

          "Person" means 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
agency or political subdivision thereof, or any other entity of whatever nature.

          "Registration Rights Agreement"  means the Registration Rights
           -----------------------------                                
Agreement, dated as of January 31, 1997, 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.

          "Responsible Officer" means, with respect to the Capital Securities
           -------------------                                               
Guarantee Trustee, any officer within the Corporate Trust Office of the Capital
Securities Guarantee Trustee, including any vice president, any assistant vice
president, any assistant secretary, any assistant treasurer, any trust officer,
any senior trust officer or other officer in the Corporate Trust Office of the
Capital Securities Guarantee Trustee customarily performing functions similar to
those performed by any of the above designated officers and also means, with
respect to a particular corporate trust matter, any other officer to whom such
matter is referred because of that officer's knowledge of and familiarity with
the particular subject.

          "Successor Capital Securities Guarantee Trustee" means a successor
           ----------------------------------------------                   
Capital Securities Guarantee Trustee possessing the

                                       5
<PAGE>
 
qualifications to act as Capital Securities Guarantee Trustee under Section 4.1.

          "Trust Indenture Act" means the Trust Indenture Act of 1939, as
           -------------------                                           
amended.

          "Trust Securities" means the Common Securities and the Series A
           ----------------                                              
Capital Securities and Series B Capital Securities, if any, collectively.


                                  ARTICLE II
                              TRUST INDENTURE ACT

SECTION 2.1    Trust Indenture Act; Application
               --------------------------------

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

          (b)  if and to the extent that any provision of this Series A 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.

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 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 ("List of Holders") as of such date, (i) within one Business Day
after December 15 and June 15 of each year, 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, that the Guarantor shall not be
                                     --------                                 
obligated to provide such List of Holders at any time the List of Holders does
not differ from the most recent 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 on receipt of a new List
of Holders.

          (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.

                                       6
<PAGE>
 
SECTION 2.3  Reports by the Capital Securities Guarantee Trustee
             ---------------------------------------------------

          Within 60 days after May 15 of each year, commencing May 15, 1997, the
Capital Securities Guarantee Trustee shall provide to the Holders such reports
as are required by Section 313(a) 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 other
requirements of Section 313 of the Trust Indenture Act.

SECTION 2.4    Periodic Reports to Capital Securities Guarantee Trustee
               --------------------------------------------------------

          The Guarantor shall provide to the Capital Securities Guarantee
Trustee such documents, reports and information as 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 provided that such compliance certificate shall
be delivered on or before 120 days after the end of each fiscal year of the
Guarantor.  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 therein or determinable from information
contained therein, 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 any conditions precedent, if any,
provided for in this Series A 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    Events of Default; Waiver
               -------------------------

          The Holders of a Majority in liquidation amount of Series A Capital
Securities may, by vote, on behalf of all the Holders, 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 A Capital Securities
Guarantee, but no such waiver shall extend to any subsequent or other default or
Event of Default or impair any right consequent thereon.

                                       7
<PAGE>
 
SECTION 2.7    Event of Default; Notice
               ------------------------

          (a)  The Capital Securities Guarantee Trustee shall, within 90 days
after the occurrence of a default with respect to this Capital Securities
Guarantee, mail by first class postage prepaid, to all Holders, notices of all
defaults actually known to a Responsible Officer of the Capital Securities
Guarantee Trustee, unless such defaults have been cured before the giving of
such notice, provided, that, except in the case of default in the payment of any
Guarantee Payment, the Capital Securities Guarantee 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 Capital Securities Guarantee Trustee in good faith determines
that the withholding of such notice is in the interests of the holders of the
Series A 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 from the Guarantor or a Holder, 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.

          (c)  Within ten Business Days after the occurrence of any Event of
Default actually known to the Capital Securities Guarantee Trustee, the Capital
Securities Guarantee Trustee shall transmit notice of such Event of Default to
the Holders of the Series A Capital Securities, unless such Event of Default
shall have been cured or waived.

SECTION 2.8    Conflicting Interests
               ---------------------

          The Declaration shall be deemed to be specifically described in this
Series A 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 A Capital Securities Guarantee shall be held by the
Capital Securities Guarantee Trustee for the benefit of the Holders, and the
Capital Securities Guarantee Trustee shall not transfer this Series A Capital
Securities Guarantee to any Person except a Holder exercising his or her rights
pursuant

                                       8
<PAGE>
 
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 A Capital
Securities Guarantee for the benefit of the Holders.

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

                                       9
<PAGE>
 
          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 A Capital Securities
          Guarantee; but 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 they conform to the requirements of this
          Series A Capital Securities Guarantee;

          (ii) the Capital Securities Guarantee Trustee shall not be liable for
     any error 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 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 action 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 A 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 power
     conferred upon the Capital Securities Guarantee Trustee under this Series
     A Capital Securities Guarantee; and

          (iv) no provision of this Series A 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 A Capital Securities Guarantee
     or indemnity, reasonably satisfactory to the Capital Securities Guarantee
     Trustee, against such risk or liability is not reasonably assured to it.

                                      10
<PAGE>
 
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, debenture, 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 A Capital Securities Guarantee may be sufficiently evidenced by an
     Officers' Certificate.

          (iii)  Whenever, in the administration of this Series A 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 any
     rerecording, 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.  The Capital Securities Guarantee
     Trustee shall have the right at any time to seek instructions concerning
     the administration of this Series A Capital Securities Guarantee from any
     court of competent jurisdiction.

          (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 A Capital Securities Guarantee at the request or direction of any
     Holder, unless such Holder shall have provided to the Capital Securities
     Guaran-

                                      11
<PAGE>
 
     tee 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 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 A
     Capital Securities Guarantee.

          (vii)  The Capital Securities Guarantee Trustee shall not be bound to
     make any investigation into the facts or matters stated in any resolution,
     certificate, statement, instrument, opinion, report, notice, request,
     direction, consent, order, bond, debenture, 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 agent or attorney 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, and the signature of the
     Capital Securities Guarantee Trustee or its agents alone shall be
     sufficient and effective to perform any such action. 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 A Capital Securities Guarantee, both of which
     shall be conclusively evidenced by the Capital Securities Guarantee
     Trustee's or its agent's taking such action.

          (x)    Whenever in the administration of this Series A 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 other action hereunder, the Capital Securities
     Guarantee Trustee (i) may request instructions from the Holders of a
     Majority in liquidation amount of the Series A Capital Securities, (ii) may
     refrain from enforcing such remedy or

                                      12
<PAGE>
 
     right or taking such other action until such instructions are received, and
     (iii) shall be protected in conclusively relying on or acting in accordance
     with such instructions.

          (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
     A Capital Securities Guarantee.

          (b)    No provision of this Series A 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 A Capital
                 ------------------------------------------------------------
                 Securities Guarantee
                 --------------------

          The recitals contained in this Series A 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 A 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 which shall:

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

          (ii)   be a corporation 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 Person permitted by the
     Securities and Exchange Commission to act as an institutional trustee under
     the Trust Indenture Act, authorized under such laws to exercise corporate
     trust powers, having a combined capital and surplus of at least 50 million
     U.S. dollars

                                      13
<PAGE>
 
     ($50,000,000), and subject to supervision or examination by Federal, State,
     Territorial or District of Columbia authority.  If such corporation
     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), 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).

          (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 Guarantor
shall in all respects comply with the provisions of Section 310(b) of the Trust
Indenture Act, subject to the penultimate paragraph thereof.

SECTION 4.2      Appointment, Removal and Resignation of Capital 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
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 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.

                                      14
<PAGE>
 
          (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 A 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.


                                   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 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 of this Series A
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 A 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:

                                      15
<PAGE>
 
          (a)    the release or waiver, by operation of law or otherwise, of the
performance or observance by the Issuer of any express or implied agreement,
covenant, term or condition relating to the Series A 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 A Capital Securities or the
extension of time for the performance of any other obligation under, arising out
of, or in connection with, the Series A Capital Securities (other than an
extension of time for payment of Distributions, Redemption Price, Liquidation
Distribution or other sum payable that results from the extension of any
interest payment period on the Debentures permitted by the Indenture);

          (c)    any failure, omission, delay or lack of diligence on the part
of the Holders to enforce, assert or exercise any right, privilege, power or
remedy conferred on the Holders pursuant to the terms of the Series A 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 A
Capital Securities;

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

          (g)    the consummation of the Exchange Offer, if any; or

          (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 obligation of the Holders to give notice to, or
obtain consent of, the Guarantor with respect to the happening of any of the
foregoing.

                                      16
<PAGE>
 
SECTION 5.4      Rights of Holders
                 -----------------

          (a)    The Holders of a Majority in liquidation amount of the Series A
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 A Capital Securities Guarantee or
exercising any trust or power conferred upon the Capital Securities Guarantee
Trustee under this Series A Capital Securities Guarantee provided, however,
                                                         --------  ------- 
that, subject to Section 3.1, the Capital Securities Guarantee Trustee shall
have the right to decline to follow any such direction if the Capital Securities
Guarantee Trustee shall determine that the action so directed would be unjustly
prejudicial to the holders not taking part in such direction or if the Capital
Securities Guarantee Trustee being advised by counsel determines that the action
or proceeding so directed may not lawfully be taken or if the Capital Securities
Guarantee Trustee in good faith by its board of directors or trustees, executive
committee, or a trust committee of directors or trustees and/or Responsible
Officers shall determine that the action or proceedings so directed would
involve the Capital Securities Guarantee Trustee in personal liability.

          (b)    If the Capital Securities Guarantee Trustee fails to enforce
such Series A Capital Securities Guarantee, any Holder may institute a legal
proceeding directly against the Guarantor to enforce the Capital Securities
Guarantee Trustee's rights under this Series A 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 A 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 against the Issuer in respect of any amounts paid to such Holders by the
Guarantor under this Series A 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 A Capital
Securities Guarantee, if, at the time of any such payment, any amounts are due
and unpaid under this Series A Capital Securities Guarantee. If any amount shall
be

                                      17
<PAGE>
 
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 A
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
A Capital Securities Guarantee notwithstanding the occurrence of any event
referred to in subsections (a) through (h), inclusive, of Section 5.3 hereof.


                                  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 (which includes common and preferred stock) or (ii)
make any payment of principal, interest or premium, if any, on or repay or
repurchase or redeem any debt securities of the Guarantor (including any 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 any securities of any subsidiary of the Guarantor (including
Other Guarantees) if such guarantee ranks pari passu or junior in right of
payment to the Debentures (other than (a) dividends or distributions in shares
of, or options, warrants, rights 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 stockholder's 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, (d) as a
direct result of, and only to the extent required in order to avoid the issuance
of fractional shares of capital stock following, 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 plans for its directors, officers or
employees or any of

                                      18
<PAGE>
 
the Guarantor's dividend reinvestment plans) if at such time (i) an Event of
Default (as defined in the Indenture) shall have occurred and be continuing,
(ii) there shall have occurred any event of which the Guarantor has actual
knowledge that (a) is, or with the giving of notice or the lapse of time, or
both, would be an Event of Default (as defined in the Indenture) and (b) in
respect of which the Guarantor shall not have taken reasonable steps to cure,
(iii) if such Debentures are held by the Property Trustee, the Guarantor shall
be in default with respect to its payment of any obligations under this Series A
Capital Securities Guarantee or (iv) the Guarantor shall have given notice of
its election of the exercise of its right to extend the interest payment period
pursuant to Section 16.01 of the Indenture and any such extension shall be
continuing.

SECTION 6.2      Ranking
                 -------

          This Series A Capital Securities Guarantee will constitute an
unsecured obligation of the Guarantor and will rank (i) subordinate and junior
in right of payment to 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 A Capital Securities Guarantee as if (x) such
Article XV were set forth herein in full and (y) such obligations were
substituted for the term "Securities" appearing in such Article XV, (ii) pari
passu with the Debentures, the Other Debentures and with the most senior
preferred or preference stock now or hereafter issued by the Guarantor and with
any Other Guarantee (as defined herein) and 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.


                                  ARTICLE VII
                                  TERMINATION

SECTION 7.1      Termination
                 -----------

          This Series A Capital Securities Guarantee shall terminate (i) upon
full payment of the Redemption Price (as defined in the Declaration) of all
Series A Capital Securities, (ii) upon liquidation of the Issuer, the full
payment of the amounts payable in accordance with the Declaration or the
distribution of the Debentures to the Holders of all of the Series A Capital
Securities or (iii) upon exchange of all the Series A Capital Securities for the
Series B Capital Securities in the Exchange Offer, if any, and the execution and
delivery of the Series B Capital Securities Guarantee, if any.  Notwithstanding
the

                                      19
<PAGE>
 
foregoing, this Series A Capital Securities Guarantee will continue to be
effective or will be reinstated, as the case may be, if at any time any Holder
must restore payment of any sums paid under the Series A Capital Securities or
under this Series A Capital Securities Guarantee.


                                 ARTICLE VIII
                         COMPENSATION AND EXPENSES OF
                     CAPITAL SECURITIES GUARANTEE TRUSTEE

SECTION 8.1      Compensation and Expenses of Capital Securities
                 -----------------------------------------------
                 Guarantee Trustee
                 -----------------

          The Guarantor covenants and agrees to pay to the Capital Securities
Guarantee Trustee from time to time, and the Capital Securities Guarantee
Trustee shall be entitled to, such compensation as shall be agreed to in writing
between the Guarantor and the Capital Securities Guarantee 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 Guarantor will pay or reimburse the
Capital Securities Guarantee Trustee upon its request for all reasonable
expenses, disbursements and advances incurred or made by the Capital Securities
Guarantee Trustee in accordance with any of the provisions of this Capital
Securities Guarantee (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 Guarantor also covenants to indemnify each of the
Capital Securities Guarantee Trustee (and its officers, agents, directors and
employees) for, and to hold it harmless against, any and all loss, damage,
claim, liability or expense including taxes (other than taxes based on the
income of the Capital Securities Guaran tee Trustee) incurred without negligence
or bad faith on the part of the Capital Securities Guarantee Trustee and arising
out of or in connection with the acceptance or administration of this guarantee,
including the costs and expenses of defending itself against any claim of
liability in the premises.  The obligations of the Guarantor under this Article
VIII to compensate and indemnify the Capital Securities Guarantee Trustee and
to pay or reimburse the Capital Securities Guarantee Trustee for expenses, 
disbursements and advances shall be secured by a lien prior to that of the
Series A Capital Securities upon all property and funds held or collected by the
Capital Securities Guarantee Trustee as such, except funds held in trust for the
benefit of the holders of particular Series A Capital Securities.

          The provisions of this Article shall survive the termination of this
Capital Securities Guarantee.

                                      20
<PAGE>
 
                                  ARTICLE IX
                                INDEMNIFICATION

SECTION 9.1      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
A 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 A 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, 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 might properly be paid.

SECTION 9.2      Indemnification
                 ---------------

          The Guarantor agrees to indemnify each Indemnified Person for, and to
hold each Indemnified Person harmless against, any and all loss, liability,
damage, 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 obligation to
indemnify as set forth in this Section 9.2 shall survive the termination of this
Series A Capital Securities Guarantee.

                                      21
<PAGE>
 
                                   ARTICLE X
                                 MISCELLANEOUS

SECTION 10.1     Successors and Assigns
                 ----------------------

          All guarantees and agreements contained in this Series A Capital
Securities Guarantee shall bind the successors, as signs, receivers, trustees
and representatives of the Guarantor and shall inure to the benefit of the
Holders then outstanding.

SECTION 10.2     Amendments
                 ----------

          Except with respect to any changes that do not materially adversely
affect the rights of Holders (in which case no consent of Holders will be
required), this Series A Capital Securities Guarantee may only be amended with
the prior approval of the Holders of a Majority in liquidation amount of the
Securities (including the stated amount that would be paid on redemption,
liquidation or otherwise, plus accrued and unpaid Distributions to the date upon
which the voting percentages are determined). The provisions of the Declaration
with respect to consents to amendments thereof (whether at a meeting or
otherwise) shall apply to the giving of such approval.

SECTION 10.3     Notices
                 -------

          All notices provided for in this Series A Capital Securities Guarantee
shall be in writing, duly 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 Holders and the Capital Securities Guarantee
Trustee):

                 Investors Capital Trust I
                 c/o Investors Financial Services Corp.
                 89 South Street
                 P.O. Box 1537
                 Boston, Massachusetts 02205-1537
                 Attention:  General Counsel
                 Telecopy:     (617) 330-6033

          (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 and the Issuer):

                                      22
<PAGE>
 
                 The Bank of New York
                 101 Barclay Street 
                 21st Floor West New York, New York 10286
                 Attention: Corporate Trust Trustee Administration 
                 Telecopy: (212) 815-5915
               

          (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 Holders of the Series A Capital Securities and the Capital Securities
Guarantee Trustee):

                 Investors Financial Services Corp.
                 89 South Street
                 P.O. Box 1537
                 Boston, Massachusetts  02205-1537
                 Attention: General Counsel
                 Telecopy:  (617) 330-6033

          (d)    If given to any Holder of Series A 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 10.4     Exchange Offer
                 --------------

          In the event an Exchange Offer Registration Statement (as defined in
the Registration Rights Agreement) becomes effective and the Issuer issues any
Series B Capital Securities in the Exchange Offer, the Guarantor will enter into
a new capital securities guarantee agreement, in substantially the same form as
this Series A Capital Securities Guarantee, with respect to the Series B Capital
Securities.

SECTION 10.5     Benefit
                 -------

          This Series A Capital Securities Guarantee is solely for the benefit
of the Holders and, subject to Section 3.1(a), is not separately transferable
from the Series A Capital Securities.

                                      23
<PAGE>
 
SECTION 10.6     Governing Law
                 -------------

          THIS SERIES A 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.

     THE HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF IS DEEMED TO HAVE
AGREED TO BE BOUND BY THE PROVISIONS OF A REGIS TRATION RIGHTS AGREEMENT AMONG
INVESTORS CAPITAL TRUST I (THE "TRUST"), INVESTORS FINANCIAL SERVICES CORP. (THE
"SPONSOR") AND KEEFE, BRUYETTE & WOODS, INC. DATED JANUARY 31, 1997 (THE
"REGISTRATION RIGHTS AGREEMENT"). THE SPONSOR WILL PROVIDE A COPY OF THE
REGISTRATION RIGHTS AGREEMENT TO A HOLDER WITHOUT CHARGE UPON WRITTEN REQUEST TO
THE TRUST AT ITS PRINCIPAL PLACE OF BUSINESS.

                                      24
<PAGE>
 
          THIS SERIES A CAPITAL SECURITIES GUARANTEE is executed as of the day
and year first above written.

                            INVESTORS FINANCIAL SERVICES CORP., 
                            as Guarantor


                               /s/ Karen C. Keenan
                            By:-----------------------------------
                               Name: karen C Keenan
                               Title:Chief Financial Officer
 
                            THE BANK OF NEW YORK, as Capital
                            Securities Guarantee Trustee


                                /s/ Mary Jane Morrissey
                            By: ----------------------------------
                               Name: MARY JANE MORRISSEY
                               Title:  VICE PRESIDENT


                                      25