SUPPLEMENT TO CURRENT PROSPECTUS AND
                      STATEMENT OF ADDITIONAL INFORMATION
                                       OF
                KEYSTONE CUSTODIAN FUND, SERIES B-1 (THE "FUND")

    The Fund's  Board of  Trustees  has  approved a change in the Fund's name to
"Keystone Quality Bond Fund (B-1)", effective May 1, 1995.

    In addition,  the name of the Fund's  investment  adviser and certain of its
affiliates  will also be changed,  effective May 1, 1995. The name of the Fund's
investment adviser will become "Keystone  Investment  Management  Company",  the
name of its principal underwriter will become "Keystone Investment  Distributors
Company" and the name of their parent company will become "Keystone Investments,
Inc."

    Finally,  the Fund's prospectus and statement of additional  information are
hereby supplemented as follows:

        "Contingent  deferred sales charges will now be waived on any redemption
    consisting  of (1) loan  proceeds  to a  retirement  plan  participant;  (2)
    financial hardship withdrawals made by a retirement plan participant; or (3)
    returns  of  excess  contributions  or  excess  deferral  amounts  made to a
    retirement plan participant."


April 28, 1995

                                                                           B1-SK