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For:       Immediate Release

Contact:   Sheila Celata (617) 726-7120


                   UST CORP. TO ACQUIRE WALDEN BANCORP, INC.


BOSTON, Massachusetts -- August 30, 1996 -- UST Corp. (NASDAQ: USTB) and
Walden Bancorp, Inc. (NASDAQ: WLDN) jointly announced today that the
Corporations have signed a definitive agreement under which UST will acquire
Walden.

The acquisition will result in UST becoming a $3.8 billion bank holding
company with 65 branches in the greater Boston area, after giving effect to
UST's pending acquisition of twenty Boston area branches from BankBoston, and
the recently announced sale of UST's Connecticut banking subsidiary, UST
Bank/Connecticut. Walden conducts business through two subsidiary banks, The
Bank of Braintree and The Co-operative Bank of Concord. These two banks have a
combined total of 17 branches located in the eastern Massachusetts counties of
Middlesex, Norfolk and Plymouth. While UST will first acquire Walden and the
banks will become subsidiaries of UST, UST anticipates that it will merge these
banks into its principal banking subsidiary, USTrust during 1997.

"This acquisition continues UST's expansion in the attractive markets of
Middlesex, Norfolk and Plymouth counties. The improved coverage substantially
enhances our market share, strengthens our geographic presence in eastern
Massachusetts, and enables USTrust to offer a stronger banking alternative to
an even larger number of local businesses and consumers," stated Neal F.
Finnegan, President and Chief Executive Officer of UST. "This acquisition of a
significant consumer and community oriented business will complement UST's
traditional strength as a commercial lender. The combination of the two
organizations will strengthen UST's position in having the third largest branch
network in metropolitan Boston. In addition, it will allow us to improve our
leverage and efficiency as we will be able to expand our customer base without
incurring proportionate increases in operating expenses. In fact, we expect the
transaction to be accretive to our earnings."

"We believe that our shareholders will greatly benefit from the proposed
transaction," stated David E. Bradbury, Chairman of the Board, President and
Chief Executive Officer of Walden. "In addition, our customers will benefit as
well as they will have access to the varied products and services of UST, along
with a much larger branch network. The pending acquisition of the BankBoston
branches represents a perfect fit with Walden's offices, and it is not
anticipated that any branches will be closed."

The transaction, which will be accounted for as a pooling of interests, is
expected to close during the first quarter of 1997, and is structured as a
tax-free exchange of 1.9 shares of UST common stock for each share of Walden
common stock. At UST's closing stock price of $16.25 on August 29, 1996, the
transaction would be valued at approximately $161 million, and Walden
shareholders would receive a value of $30.875 in UST common stock for each
share of Walden common stock. The purchase price represents a multiple of 1.69
times stated book value of Walden, and 1.96 times tangible book value of Walden
at June 30, 1996. The Company expects to record a one-time pre-tax charge of
approximately $13.5 million of acquisition related costs in connection with the
transaction.




The agreement is subject to the approval of the shareholders of UST and Walden
as well as federal and state bank regulatory authorities. In connection with
the merger agreement, Walden has granted UST an option to purchase
approximately 19.9% of its common stock exercisable upon the occurrence of
certain events.

UST is a $2 billion, Boston-based bank holding company which provides a broad
range of financial services to individuals and small and medium sized companies
in New England. In June 1996, UST announced an agreement with BankBoston to
acquire a total of twenty BayBank and Bank of Boston branches, with
approximately $860 million in deposits and approximately $510 million of
commercial, residential and other loans.

Walden Bancorp is a $1 billion bank holding company for two community banks
which specialize in meeting consumer and small business banking needs in their
local markets with a total of 17 branch offices in Middlesex, Norfolk and
Plymouth counties.