EXHIBIT 21


Subsidiaries of UST Corp.(*)

        USTrust
        United States Trust Company
        JSA Financial Corporation
        UST Leasing Corporation (**)
        UST Securities Corp. (**)
        Mosaic Corp.
        UST Capital Corp. (***)
        USTrust Securities Corp. (****)

(*)     Each  of  the  above  subsidiaries  of  UST  Corp.  is  a  Massachusetts
        Corporation  or  trust  company  and  each of the  above  entities  does
        business  only under its  corporate  name with the exception of USTrust,
        which does business  under the name  "USTrust  Bank" as well as the name
        "USTrust."  The  foregoing  list does not  include the names of inactive
        subsidiaries  or the names of  subsidiaries  of banking  entities  which
        subsidiaries have been organized to hold foreclosed  property,  or other
        assets  held in  satisfaction  of  debts  previously  contracted  by the
        applicable banking entity.

(**)    Wholly-owned by USTrust

(***)   Wholly-owned by United States Trust Company

(****)  Organized  as a  wholly-owned  subsidiary  of UST  Securities  Corp.  on
        February 24, 1997.


As of January 3, 1997, the following additional companies became subsidiaries of
the Company:

The Co-operative Bank of Concord
The Braintree Savings Bank
Walden Financial Corp.
Builders Collaborative, Inc.
Braintree Savings Corporation
Walden Securities Corporation, Inc.
Bra-Prop Corporation
Braintree Securities Corp.