EXHIBIT 10.21

                  SUPPLEMENTAL DEFINED BENEFIT PENSION PLAN

ARTICLE 1.  ARTICLE ESTABLISHMENT AND PURPOSE
     1.1  ESTABLISHMENT.  State Street Boston Corporation (the "Company") hereby
establishes  a  supplemental  defined  benefit  pension plan known as the "State
Street  Boston  Corporation  Supplemental  Defined  Benefit  Pension  Plan" (the
"Plan") effective as of January 1, 1995 (the "Effective Date").

     1.2 PURPOSE.  The principal  purposes of this Supplemental  Defined Benefit
Pension Plan (the "Plan") are to provide certain key employees with  competitive
retirement  benefits,  protect against reductions in retirement  benefits due to
tax  law  limitations  on  qualified  plans,  and  to  encourage  the  continued
employment of such employees with the Company.

ARTICLE 2.  DEFINITIONS
     2.1  ACTUARIALLY   EQUIVALENT.   "Actuarially   Equivalent"  or  "Actuarial
Equivalent"  means the  equivalence  in present  value between two or more forms
and/or times of payment based upon a  determination  by an actuary chosen by the
Committee,  using  the  actuarial  assumptions  in  effect  at the  time of such
determination with respect to the Basic Plan.

     2.2 ADDITIONAL  COMPANY  BENEFIT.  "Additional  Company  Benefit" means the
annual  retirement  supplemental  benefit  payable  to a  Participant  under the
Amended  and  Restated  Supplemental  Retirement  Plan,  or any  other  Company-
sponsored supplemental retirement plans or other arrangements,  as determined by
the Committee, in the form of a straight life annuity.

     2.3 BANK. "Bank" means State Street Bank and Trust Company, a Massachusetts
trust company which is a subsidiary of the Company.

     2.4 BASIC PLAN.  "Basic Plan" means the State Street Retirement Plan as may
be amended  from time to time,  and any  successor  defined  benefit  retirement
income plan or plans  maintained  by the Company which qualify under Section 401
(a) of the Internal Revenue Code.

     2.5 BASIC PLAN OFFSET.  "Basic Plan Offset"  means the annual  benefit that
would be paid from the Basic  Plan to a  Participant  in the form of a  straight
life annuity from the qualifying employment  termination date, regardless of the
amount actually paid or the actual method of payment under the Basic Plan.

     2.6 BOARD. "Board" means the Board of Directors of the Company.

     2.7 CAUSE. "Cause" means:

     (i) the  willful  and  continued  failure  of the  Participant  to  perform
substantially  the  Participant's  duties with the Company  (other than any such
failure  resulting from incapacity due to physical or mental  illness),  after a
written demand for  substantial  performance is delivered to the  Participant by
the Participant's  supervisor which specifically  identifies the manner in which
it is  asserted  that  the  Participant  has  not  substantially  performed  the
Participant's duties, or

     (ii) the willful  engaging by the  Participant in illegal  conduct or gross
misconduct which is materially and demonstrably injurious to the Company.

For  purposes of this  provision,  no  act  or  failure  to act,  on the part of
the Participant,  shall be considered "willful" unless it is done, or omitted to
be done, by the Participant in bad faith or without  reasonable  belief that the
Participant's action or omission was in the best interests of the Company.

     2.8 COMMITTEE.  "Committee" means the Executive  Compensation  Committee of
the Board.

     2.9  COMPANY.   "Company"  means  State  Street  Boston  Corporation,   any
subsidiary  of State Street  Boston  Corporation,  including  the Bank,  and any
successor companies,  and any other entity with employees who participate in the
Basic Plan that is designated by the Committee.

     2.10 CREDITED SERVICE.  "Credited  Service" means a Participant's  years of
credited  service or benefit  service  as defined in the Basic Plan  which,  for
purposes of the Plan,  shall  continue to accrue during any period of Disability
of a Participant, as defined by the State Street Retirement Plan.

     2.11  EARLY  RETIREMENT.  "Early  Retirement"  means any  termination  of a
Participant's  employment during the time period  constituting  Early Retirement
Age  other  than:  (i) a  voluntary  termination  without  the  consent  of  the
Committee; or (ii) an involuntary termination for Cause.

     2.12 EARLY  RETIREMENT AGE. "Early  Retirement Age" means,  for purposes of
this  Plan,  the time  period  occurring  after and  including  a  Participant's
attainment of age fifty-five (55) and prior to attaining age sixty-five (65).

     2.13 EARNINGS.  "Earnings" means a Participant's  total annual base salary,
unreduced  by  voluntary  deferrals  of  base  salary  by  a  Participant  under
Company-sponsored plans; plus any cash annual incentive compensation awards; and
does not  include  any  long-term  incentive  awards  paid by the  Company  to a
Participant during the period of reference. For purposes of determining Earnings
for any particular  year,  Earnings for the year shall consist of base salary as
of January 1 of that year and annual incentive  compensation  awards relating to
such  Participant's  performance  in the prior fiscal year,  regardless  of when
paid.

     2.14  EMPLOYMENT.  "Employment"  means the period or periods during which a
Participant is an employee of the Company.

     2.15 ERISA.  "ERISA" means the Employee Retirement Income Security,  Act of
1974, as amended, and any successor act thereto.

     2.16 FINAL AVERAGE EARNINGS. "Final Average Earnings" means a Participant's
highest average of any five consecutive  years Earnings during the last ten (10)
years of a Participant's Employment.

     2.17 NORMAL  RETIREMENT.  "Normal  Retirement"  means any  termination of a
Participant's  employment during the time period  constituting Normal Retirement
Age other than an involuntary termination for Cause.

     2.18 NORMAL RETIREMENT AGE. "Normal  Retirement Age" means, for purposes of
this Plan, the time period occurring on and after a Participant's  attainment of
age sixty-five (65).

     2.19 OTHER RETIREMENT  INCOME.  "Other Retirement  Income" means the sum of
the retirement income payable to a Participant as set forth below:

     (a) Basic Plan Offset; plus

     (b) Additional Company Benefit; plus

     (c)  Retirement  income  payable under plans of a  Participant's  employers
          other than the Company,  expressed  in  the  form of a  straight  life
          annuity, as determined by the Committee.

     2.20 PARTICIPANT.  "Participant" means an eligible employee of the Company,
selected to receive benefits under the Plan as provided in Article 3, herein.

     2.21 RETIREMENT. "Retirement" and "Retire" means Normal Retirement or Early
Retirement.

     2.22 SPOUSE.  "Spouse" means an individual who is a spouse as defined under
the Basic Plan.

     2.23 TOP HAT  PLAN.  "Top Hat Plan"  means a  nonqualified,  unfunded  plan
maintained primarily to provide deferred  compensation benefits to a Participant
who falls within a select group of "management or highly compensated  employees"
within the meaning of Sections 201, 301, and 401 of ERISA.

ARTICLE 3.  RETIREMENT
    3.1 ELIGIBILITY.   Only those employees who comprise a select group of
     management or highly compensated employees, such that the Plan will qualify
for treatment as a Top Hat Plan,  will be eligible to be selected to participate
in the Plan, as provided below.

     3.2  PARTICIPATION.  The Committee,  or such person or entity designated by
the Committee,  acting in its discretion, may designate any eligible employee as
a Participant under this Plan. Such designation shall be in writing and shall be
effective  as of the  date  contained  therein.  Participation  in the  Plan  is
terminable  by the  Committee,  in its  discretion,  upon written  notice to the
Participant,  and  termination  shall  be  effective  as of the  date  contained
therein, but no event earlier than the date of such notice.

     3.3 FORFEITURE. In the event that a Participant's Employment terminates for
any reason (including without limitation if the Participant's employer ceases to
be an entity meeting the  definition of the "Company"  under this Plan) prior to
the  Participant's  (a) reaching age fifty-five  (55) or (b) completing ten (10)
full  years of  Employment  with the  Company as of the date of  termination  of
Employment,  then such Participant shall forfeit his or her right to receive any
and all  benefits  set forth in this Plan,  unless  determined  otherwise by the
Committee,  in  its  sole  discretion.  After  the  later  of  such  dates,  the
Participant  shall have a vested  benefit which shall become payable as provided
below upon his Normal Retirement or Early Retirement hereunder.

     3.4 NONCOMPETITION.  Notwithstanding any other provisions hereof, neither a
Participant  nor  spouse  nor any other  beneficiary  of the  Participant  shall
receive any further benefits hereunder if the Participant, without prior written
consent of the Committee engages,  either directly or indirectly,  in any of the
activities  described  in (i)  (ii) and  (iii)  below  within  two  years  after
termination of employment with the Company:

        (i)  employment or retention of any person whom the Company has,  during
     the  two-year  period  prior to such  termination  of  employment  with the
     Company,  employed or retained.  For purposes of the foregoing sentence,  a
     person  retained by the Company  means anyone who has rendered  substantial
     consulting  services  to the  Company  and has  thereby  acquired  material
     confidential information concerning any aspect of the Company's operations;

        (ii)  sale,  offer to sell,  or  negotiation  with  respect to orders or
     contracts  for any  product or service  similar to, or  competitive  with a
     product or service,  or any equipment or system containing any such product
     or service  sold or offered by the  Company,  other than for the  Company's
     account,  during the two-year period after such  termination of employment,
     to or with anyone  with whom the  Company has so dealt,  or anywhere in any
     state of the United States or in any other country, territory or possession
     in which the Company has, during said period,  sold, offered, or negotiated
     with  respect  to  orders  or  contracts  for any  such  product,  service,
     equipment or system; or

        (iii)  ownership  of any direct or  indirect  interest  in (other than a
     less-than-1%  stock interest in a  corporation),  or  affiliation  with, or
     rendition of any services for, any person or business entity which engages,
     during  the  two-year  period  after  the   Participant's   termination  of
     employment,  either  directly  or  indirectly,  in any  of  the  activities
     described in subparagraph (i) or (ii) above.

ARTICLE 4.  AMOUNT, FORM, AND PAYMENT OF SUPPLEMENTAL BENEFIT

     4.1 NORMAL  RETIREMENT  BENEFIT.  Subject  to the terms of this  Plan,  the
annual  supplemental  benefit  payable to a Participant  hereunder in connection
with Normal  Retirement,  calculated as a straight life annuity,  will equal the
amount  specified  below in Subsection  (a), less the amount  specified below in
Subsection (b):

     (a) Fifty percent (50%) of Final Average Earnings; less

     (b) Other Retirement Income.

     4.2 EARLY RETIREMENT BENEFIT. Subject to the terms of this Plan, the annual
benefit payable to a Participant  hereunder in connection with Early  Retirement
shall equal the annual supplemental  benefit (calculated as described in Section
4.1 above), reduced by an amount equal to:

        (a) .0833% for each whole calendar month by which a  Participant's  date
     of  termination  of  Employment  is before  his or her  sixty-fifth  (65th)
     birthday but is on or after such  Participant's  sixtieth (60th)  birthday;
     and

        (b) 2.2083% for each whole calendar month by which a Participant's  date
     of termination of Employment is before his or her sixtieth  (60th) birthday
     but is on or after such Participant's fifty-fifth (55th) birthday.

     4.3 FORM  OF  BENEFIT.  A  Participant's   election  as  to  the  form  and
commencement  of his benefit under the Basic Plan shall  automatically  apply to
the payment of his Benefit. Any consent or waiver effected by a Participant or a
Participant's  Spouse under any provision of the Basic Plan shall  automatically
operate  as a  consent  to  the  corresponding  election  or  a  waiver  of  the
corresponding benefit or right under the Plan.

ARTICLE 5.  ADMINISTRATION
     5.1  AUTHORITY OF THE  COMMITTEE.  This Plan shall be  administered  by the
Committee or any other committee designated by the Board to administer the Plan.
Subject to the provisions of the Plan, the Committee shall have the authority to
make,  amend,  interpret,  and enforce all appropriate rules and regulations for
the  administration of this Plan and to decide or resolve any and all questions,
including  interpretations  of this Plan, as may arise in  connection  with this
Plan.

     5.2 AGENTS.  In the  administration  of this Plan,  the Committee may, from
time to time,  employ  agents and  delegate to such  agents such  administrative
duties as it deems advisable and allowable under the terms of the Plan.

     5.3 DECISIONS BINDING. The decision or action of the Committee with respect
to  any  question  arising  out of or in  connection  with  the  administration,
interpretation, and application of this Plan and any rules or guidelines made in
connection with the Plan shall be final,  and  conclusive,  and shall be binding
upon all persons and entities having any interest in this Plan.

     5.4 INDEMNITY OF COMMITTEE.  The Company shall  indemnify and hold harmless
the  Committee  and its  individual  members  against any and all claims,  loss,
damage,  expense,  or  liability  arising from any action or failure to act with
respect to this Plan.

     5.5  COST OF  ADMINISTRATION.  The  Company  shall  bear  all  expenses  of
administration of this Plan.

ARTICLE 6.  BENEFICIARY DESIGNATION
     6.1  DESIGNATION  OF  BENEFICIARY.  Each  Participant  shall be entitled to
designate a beneficiary or beneficiaries who, upon the Participant's death, will
receive the amounts that otherwise would have been paid to the Participant under
the Plan as calculated under Article 4 herein.  All designations shall be signed
by the  Participant,  and shall be in such form as prescribed by the  Committee.
The Participant may change his or her designation of beneficiary at any time, on
such form as  prescribed  by the  Committee.  The  filing  of a new  beneficiary
designation  form  by  a  Participant  shall  automatically   revoke  all  prior
designations by that Participant.

     6.3 DEATH OF BENEFICIARIES.  In the event that all the beneficiaries  named
by a Participant pursuant to Section 6.1 herein predecease the Participant,  the
amounts that otherwise would have been paid to the Participant  shall be paid to
the Participant's estate.

     6.3  INEFFECTIVE  DESIGNATION.  In  the  event  the  Participant  does  not
designate  a  beneficiary  pursuant  to this  Article 6, or for any reason  such
designation is ineffective in whole or in part, the amounts that otherwise would
have been paid to the Participant shall be paid to the Participant's estate.

ARTICLE 7.  AMENDMENT AND TERMINATION
     The Company hereby  reserves the right to amend,  modify,  or terminate the
Plan at any time by action of a majority of the members of the Committee. Except
as described below in this Article 7, no such amendment or termination  shall in
any material  manner  reduce or  adversely  affect any  Participant's  rights to
vested benefits hereunder without the consent of the Participant.

     The Plan is intended to be a Top Hat Plan and  therefore  to be exempt from
the provisions of Parts 2, 3, and 4 of Title I of ERISA. Accordingly,  the Board
may  terminate  the Plan and  commence  termination  payout  for all or  certain
Participants,  or remove certain employees as Participants,  if it is determined
by the United States  Department  of Labor or a court of competent  jurisdiction
that the Plan constitutes an employee pension benefit plan within the meaning of
Section 3(2) of ERISA which is not so exempt. If payout is commenced pursuant to
the  operation of this  Article 7, the payment of such amounts  shall be made in
the manner, and at the times selected by the Committee;  provided, however, that
such payment  shall not be extended for a longer  period of time than would have
been the case had the payment of  benefits  occurred  as  scheduled  immediately
prior to such accelerated payout.

ARTICLE 8.  MISCELLANEOUS
     8.1 UNFUNDED PLAN. This Plan is intended to be a Top Hat Plan and therefore
exempt from the provisions of Parts 2, 3, and 4 of Title I of ERISA. Such status
shall not be adversely  affected by the  establishment  of any trust pursuant to
Section 8.3 below.

     8.2  UNSECURED   GENERAL   CREDITOR.   Each  Participant  and  his  or  her
beneficiaries,  heirs,  successors,  and assigns  shall have no secured legal or
equitable rights,  interest, or claims in any property or assets of the Company,
nor shall any such  persons  have any rights,  claims,  or interests in any life
insurance policies,  annuity contracts, or the proceeds therefrom owned or which
may be  acquired  by the  Company.  Except as  provided  in  Section  8.3,  such
policies,  annuity  contracts,  or other assets of the Company shall not be held
under any trust for the  benefit  of a  Participant,  his or her  beneficiaries,
heirs,  successors or assigns,  or held, in any way, as collateral  security for
the fulfilling of any obligations of the Company under this Plan. Any and all of
the  Company's  assets and  policies  shall be, and shall remain for purposes of
this Plan,  the general,  unpledged,  unrestricted  assets of the  Company.  The
Company's  obligation under this Plan shall be that of an unfunded and unsecured
promise to pay money in the future.

     8.3 TRUST FUND.  At its  discretion,  the Company may establish one or more
grantor trusts,  with such trustees as the Committee may approve for the purpose
of providing for the payment of benefits  under this Plan.  Such trust or trusts
may be irrevocable, but the assets thereof shall be subject to the claims of the
Company's general creditors. To the extent any benefits provided under this Plan
are  actually  paid from any such  trust,  the  Company  shall  have no  further
obligation  with respect  thereto,  but to the extent not so paid, such benefits
shall remain the obligation of, and shall be paid by, the Company.

     8.4  NONASSIGNABILITY.  Neither a Participant  nor any,  other person shall
have any right to sell,  assign,  transfer,  pledge,  anticipate,  mortgage,  or
otherwise  encumber,  hypothecate  or convey in  advance of actual  receipt  the
amounts,  if any,  payable  hereunder,  or any part thereof,  which are, and all
rights to which are, expressly declared to be nonassignable and nontransferable.
No part of the amount  payable  shall,  prior to actual  payment,  be subject to
seizure or  sequestration  for the payment of any debts,  judgments,  alimony or
separate  maintenance owed by a Participant or any other person,  nor shall such
amounts or rights to such  amounts be  transferable  by  operation of law in the
event of a Participant's or any other person's bankruptcy or insolvency.

     8.5 NOT A CONTRACT OF  EMPLOYMENT.  The terms and  conditions  of this Plan
shall not be deemed to constitute a contract of  employment  between the Company
and any Participant,  and Participants (and Participants'  beneficiaries)  shall
have no rights  against  the Company  except as may  otherwise  be  specifically
provided  herein.  Moreover,  nothing  in this  Plan  shall be  deemed to give a
Participant  the  right to be  retained  in the  service  of the  Company  or to
interfere  with  the  right  of the  Company  to  discipline  or  discharge  any
Participant at any time.

     8.6  VALIDITY.  If any  provision  of this Plan  shall be held  illegal  or
invalid for any  reason,  said  illegality  or  invalidity  shall not affect the
remaining parts hereof, but this Plan shall be construed and enforced as if such
illegal and invalid provision had never been inserted herein.

     8.7  SUCCESSORS.  The  provisions  of this Plan shall bind and inure to the
benefit of the Company and its  successors  and assigns,  and the Company  shall
require all its  successors  and  assigns to  expressly  assume its  obligations
hereunder. The Term "successors," as used herein, shall include any corporate or
other business entity which shall, whether by merger, consolidation, purchase or
otherwise,  acquire all or  substantially  all of the business and assets of the
Company.

     8.8  TAX  WITHHOLDING.   The  Company  shall  have  the  right  to  require
Participants  to remit to the Company an amount  sufficient to satisfy  Federal,
state,  and local tax withholding  requirements,  or to deduct from payment made
pursuant  to the  Plan  amounts  sufficient  to  satisfy  such  tax  withholding
requirements.

     8.9 GOVERNING LAW. The provisions of this Agreement  shall be construed and
interpreted according to the laws of the Commonwealth of Massachusetts except as
preempted by Federal law.