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                                                                  EXHIBIT 10(r)

[UST Corp.]
                                                           September 27, 1994

PRIVILEGED AND CONFIDENTIAL
---------------------------

Paul M. Siskind, Esq.
20 Hammond Pond Parkway
Apt. No. 505
Chestnut Hill, MA 02167

Dear Paul:

         This letter agreement ("Letter Agreement") is intended to summarize
the terms of UST Corp.'s ("UST") agreement with you related to your resignation
as UST's Chairman of the Board.

         1. You have submitted your resignation as Chairman of the Board and as
         a Director of UST, effective October 18, 1994.

         2. In recognition of certain additional remuneration from UST that you
         will be foregoing and the additional health insurance costs which you
         will be incurring as a result of your resignation, UST will make a
         lump sum payment to you of $55,000 in January 1995.

         3. In consideration of your providing guidance to the new Chairman of
         the Board concerning the most effective way to perform his/her
         responsibilities and your providing ongoing advice concerning the
         corporate governance of UST, UST has also agreed to pay you $35,000
         per annum (for each applicable year) throughout your lifetime. This
         benefit will cease upon the date of your death. The foregoing payments
         will be made semi-annually in advance: $17,500 in December and $17,500
         in June of each applicable year. The first $17,500 payment will be
         made in December 1994.

         4. You will be given an opportunity to review and approve any portion
         of the UST Press Release relating to your resignation as Chairman of
         the Board.

         5. Your Administrative Assistant, Maureen Reggiannini, will be paid
         her salary at the rate of $17,500 per annum through December 31, 1994
         and, after October 18, 1994, all of her work assignments will be
         initiated only by you.

         6. UST recognizes your tenancy-at-will (monthly) concerning Rm. No.
         605, on the 6th Floor, 40 Court Street, Boston, Massachusetts and
         described in the Agreement of Lease which you signed on March 30,
         1994. You will be permitted to terminate this tenancy upon thirty (30)
         days prior written notice with your rental obligation ending on the
         later of the end of the notice period or your actual date of departure
         from the premises.
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         7. The financial terms of this Letter Agreement remain subject to
         receipt of written approval from the Federal Reserve Bank of Boston
         and the Office of the Massachusetts Commissioner of Banks.

         8. All other benefits to you from UST, not covered above, will cease
         as of October 18, 1994.

         On behalf of the Board of Directors of UST Corp., I want to express
our enormous debt of gratitude to you for more than 25 years of outstanding
leadership.

                                              Very truly yours,

                                              /s/ Neal F. Finnegan
                                              --------------------              
                                              Neal F. Finnegan
                                              President and
                                              Chief Executive Officer

AGREED AND ACCEPTED:

/s/ Paul M. Siskind
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cc:      Eric R. Fischer, Clerk
         Linda J. Lerner, Senior Vice President/Human Resources