content: <PAGE>   1
    As filed with the Securities and Exchange Commission on December 1, 1994
  
                                                              Registration No. 33-
  ================================================================================
  
                        SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, D.C. 20549
  
                            --------------------------
  
                                     FORM S-8
  
                              REGISTRATION STATEMENT
                                      UNDER
                            THE SECURITIES ACT OF 1933
  
                            --------------------------
  
                                    UST CORP.
              (Exact name of registrant as specified in its charter)
  
                                 40 COURT STREET
                           BOSTON, MASSACHUSETTS 02108
                                  (617) 726-7000
           (Address of principal executive offices, including zip code)
  
  
     MASSACHUSETTS      UST CORP. STOCK COMPENSATION PLAN         04-2436093
    (State or other         (Full title of the plan)           (I.R.S. Employer
    jurisdiction of                                             Identification
    or organization)                                                Number)
  
                            --------------------------
  
                              ERIC R. FISCHER, ESQ.
               EXECUTIVE VICE PRESIDENT, GENERAL COUNSEL AND CLERK
                                    UST CORP.
                                 40 COURT STREET
                           BOSTON, MASSACHUSETTS 02108
                                  (617) 726-7000
               (Name and address, including zip code, and telephone
                number, including area code, of agent for service)
  
                            --------------------------
  <TABLE>
                                         CALCULATION OF REGISTRATION FEE
  <CAPTION>
  ==============================================================================================================
                                          Amount         Proposed maximum      Proposed maximum      Amount of
         Title of each class of           to be           offering price      aggregate offering    registration
       securities to be registered     registered(1)       per share(2)            price(2)             fee          
  - --------------------------------------------------------------------------------------------------------------
  <S>                                  <C>               <C>                  <C>                   <C>
  Common Stock -- $.625 par value...   1,000,000 shs.    $ 10.1875            $ 10,187,500          $ 3,513
  ==============================================================================================================
  </TABLE>
  
  (1) This Registration Statement also covers such indeterminable number of 
      additional shares of Common Stock, par value $.625 ("Common Stock"), of UST
      Corp. as may become deliverable as a result of future adjustments in 
      accordance with the terms of the UST Corp. Stock Compensation Plan.
  
  (2) The offering price has been estimated solely for the purpose of determining
      the registration fee pursuant to Rule 457(h) on the basis of the average of
      the high and low prices for the Common Stock of UST Corp. on November 28, 
      1994, as reported on the NASDAQ National Market System.
  
  ================================================================================
  
                            EXHIBIT INDEX ON PAGE 5;
                               PAGE 1 OF 5 PAGES.
  
  
  <PAGE>   2
                                     PART II
  
                INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  
  INCORPORATION BY REFERENCE
  
           Pursuant to General Instruction E to Form S-8, the contents of the
  Registrant's earlier Registration Statement on Form S-8 (file number 33-54390)
  are hereby incorporated by reference thereto.
  
  Item 5.  Interests of Named Experts and Counsel.
  
           Certain legal matters in connection with the offering of the shares of
           common stock, par value $.625 ("Common Stock"), of the Registrant are 
           being passed upon for the Registrant by Eric R. Fischer, Esq., who is 
           Executive Vice President, General Counsel and Clerk of the Registrant. 
           As of December 1, 1994, Mr. Fischer beneficially owned 14,019 shares 
           of Common Stock; options to acquire 41,780 shares of Common Stock 
           which were exercisable within sixty (60) days; and options to acquire 
           an additional 4,630 shares of Common Stock which were exercisable 
           thereafter.
  
  
  Item 8.  Exhibits.
  
  Exhibit
  
  4.1      UST Corp. Stock Compensation Plan, as amended and restated on 
           November 15, 1994.
  
  5.1      Opinion of Eric R. Fischer, Esq.
  
  23.1     Consent of Arthur Andersen LLP
  
  23.2     Consent of Eric R. Fischer, Esq. (contained in the opinion filed as
           Exhibit 5.1 hereto).
  
  24       Powers of Attorney (included in signature page hereto).
  
  
  
                                      
  <PAGE>   3
                                    SIGNATURES
  
  
       Pursuant to the requirements of the Securities Act of 1933, the Registrant
  certifies that it has reasonable grounds to believe that it meets all of the
  requirements for filing on Form S-8 and has duly caused this registration
  statement on Form S-8 to be signed on its behalf by the undersigned, thereunto
  duly authorized, in the City of Boston, The Commonwealth of Massachusetts, on
  this 15th day of November, 1994.
  
                                        UST CORP.
  
  
                                        By /s/ Neal F. Finnegan
                                           -------------------------------------
                                           Neal F. Finnegan
                                           President and Chief Executive Officer
  
  
                                POWER OF ATTORNEY
  
       Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.  Each person whose signature appears
  below hereby authorizes and constitutes Eric R. Fischer, Esq. and Neal F.
  Finnegan, and each of them singly, his true and lawful attorneys with full
  power to them, and each of them singly, to sign for him and in his name in the
  capacities indicated below any and all amendments (including post-effective
  amendments) to this Registration Statement and to file the same, with exhibits
  thereto, and other documents in connection therewith, and he hereby ratifies
  and confirms his signature as it may be signed by said attorneys, or any of
  them, to any and all such amendments.
  
  <TABLE>
  <CAPTION>
  SIGNATURE                          CAPACITY IN WHICH SIGNED             DATE
  - ---------                          ------------------------             ----
  <S>                                <C>                                  <C>
  /s/ Neal F. Finnegan               President, Chief Executive           November 15, 1994
  - -----------------------            Officer and Director (principal
  Neal F. Finnegan                   executive officer)
  
  
  
  /s/ James K. Hunt                  Executive Vice President,            November 15, 1994
  - -----------------------            Treasurer and Chief Financial
  James K. Hunt                      Officer (principal financial
                                     officer and principal accounting
                                     officer)
  
  
  /s/ Eric R. Fischer                Executive Vice President,            November 15, 1994
  - -----------------------            General Counsel and Clerk
  Eric R. Fischer
  
  
  /s/ William Schwartz               Vice Chairman and Director           November 15, 1994
  - -----------------------
  William Schwartz
  
  
  /s/ Domenic Colasacco              Executive Vice President and         November 15, 1994
  - -----------------------            Director
  Domenic Colasacco
  </TABLE>
  
  
                                       
  <PAGE>   4
  <TABLE>
  <S>                                <C>                                         <C>
  /s/ James M. Breiner               Director                                    November 15, 1994
  - --------------------------         
  James M. Breiner
  
  
  /s/ Robert L. Culver               Director                                    November 15, 1994
  - --------------------------
  Robert L. Culver
  
  
  /s/ Walter A. Guleserian           Director                                    November 15, 1994
  - --------------------------
  Walter A. Guleserian
  
  
  /s/ Wallace M. Haselton            Director                                    November 15, 1994
  - --------------------------
  Wallace M. Haselton
  
  
  /s/ Francis X. Messina             Director                                    November 15, 1994
  - --------------------------
  Francis X. Messina
  
  
  /s/ Gerald M. Ridge                Director                                    November 15, 1994
  - --------------------------
  Gerald M. Ridge
  
  
  /s/ Samuel B. Sheldon              Director                                    November 15, 1994
  - --------------------------
  Samuel B. Sheldon
  
  
  /s/ James V. Sidell                Director                                    November 15, 1994
  - --------------------------
  James V. Sidell
  
  
  /s/ Paul D. Slater                 Director                                    November 15, 1994
  - --------------------------
  Paul D. Slater
  
  
  /s/ Michael D. Verrochi            Director                                    November 15, 1994
  - --------------------------
  Michael D. Verrochi
  </TABLE>
  
  
  
                                       
  <PAGE>   5
                                  EXHIBIT INDEX
  
  <TABLE>
  <CAPTION>
  Number                         Title of Exhibit                         Page
  - ------                         ----------------                         ----
  <S>                 <C>                                                 <C>
   4.1                UST Corp. Stock Compensation Plan, as
                      amended and restated on November 15, 1994
  
   5.1                Opinion of Eric R. Fischer, Esq.
  
   23.1               Consent of Arthur Andersen LLP
  
   23.2               Consent of Eric R. Fischer, Esq. (contained in
                      the opinion filed as Exhibit 5.1 hereto).
  
   24                 Powers of Attorney (included in signature
                      page hereto).
  </TABLE>
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "UST CORP. STOCK COMPENSATION PLAN", "secsgml_size_bytes": 10435}]
metadata_filer: {"company-data": {"conformed-name": "UST CORP", "cik": "0000316901", "assigned-sic": "6021", "irs-number": "042436093", "state-of-incorporation": "MA", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "033-56687", "film-number": "94562822"}, "business-address": {"street1": "40 COURT ST", "city": "BOSTON", "state": "MA", "zip": "02108", "phone": "6177267000"}}
text: 1
    As filed with the Securities and Exchange Commission on December 1, 1994
  
                                                              Registration No. 33-
  ================================================================================
  
                        SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, D.C. 20549
  
                            --------------------------
  
                                     FORM S-8
  
                              REGISTRATION STATEMENT
                                      UNDER
                            THE SECURITIES ACT OF 1933
  
                            --------------------------
  
                                    UST CORP.
              (Exact name of registrant as specified in its charter)
  
                                 40 COURT STREET
                           BOSTON, MASSACHUSETTS 02108
                                  (617) 726-7000
           (Address of principal executive offices, including zip code)
  
     MASSACHUSETTS      UST CORP. STOCK COMPENSATION PLAN         04-2436093
    (State or other         (Full title of the plan)           (I.R.S. Employer
    jurisdiction of                                             Identification
    or organization)                                                Number)
  
                            --------------------------
  
                              ERIC R. FISCHER, ESQ.
               EXECUTIVE VICE PRESIDENT, GENERAL COUNSEL AND CLERK
                                    UST CORP.
                                 40 COURT STREET
                           BOSTON, MASSACHUSETTS 02108
                                  (617) 726-7000
               (Name and address, including zip code, and telephone
                number, including area code, of agent for service)
  
                            --------------------------
  
                                         CALCULATION OF REGISTRATION FEE
  ==============================================================================================================
                                          Amount         Proposed maximum      Proposed maximum      Amount of
         Title of each class of           to be           offering price      aggregate offering    registration
       securities to be registered     registered(1)       per share(2)            price(2)             fee          
  - --------------------------------------------------------------------------------------------------------------
  Common Stock -- $.625 par value...   1,000,000 shs.    $ 10.1875            $ 10,187,500          $ 3,513
  ==============================================================================================================
  (1) This Registration Statement also covers such indeterminable number of 
      additional shares of Common Stock, par value $.625 ("Common Stock"), of UST
      Corp. as may become deliverable as a result of future adjustments in 
      accordance with the terms of the UST Corp. Stock Compensation Plan.
  
  (2) The offering price has been estimated solely for the purpose of determining
      the registration fee pursuant to Rule 457(h) on the basis of the average of
      the high and low prices for the Common Stock of UST Corp. on November 28, 
      1994, as reported on the NASDAQ National Market System.
  
  ================================================================================
  
                            EXHIBIT INDEX ON PAGE 5;
                               PAGE 1 OF 5 PAGES.
  2
                                     PART II
  
                INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  INCORPORATION BY REFERENCE
  
           Pursuant to General Instruction E to Form S-8, the contents of the
  Registrant's earlier Registration Statement on Form S-8 (file number 33-54390)
  are hereby incorporated by reference thereto.
  
  Item 5.  Interests of Named Experts and Counsel.
  
           Certain legal matters in connection with the offering of the shares of
           common stock, par value $.625 ("Common Stock"), of the Registrant are 
           being passed upon for the Registrant by Eric R. Fischer, Esq., who is 
           Executive Vice President, General Counsel and Clerk of the Registrant. 
           As of December 1, 1994, Mr. Fischer beneficially owned 14,019 shares 
           of Common Stock; options to acquire 41,780 shares of Common Stock 
           which were exercisable within sixty (60) days; and options to acquire 
           an additional 4,630 shares of Common Stock which were exercisable 
           thereafter.
  
  Item 8.  Exhibits.
  
  Exhibit
  
  4.1      UST Corp. Stock Compensation Plan, as amended and restated on 
           November 15, 1994.
  
  5.1      Opinion of Eric R. Fischer, Esq.
  
  23.1     Consent of Arthur Andersen LLP
  
  23.2     Consent of Eric R. Fischer, Esq. (contained in the opinion filed as
           Exhibit 5.1 hereto).
  
  24       Powers of Attorney (included in signature page hereto).
  3
                                    SIGNATURES
  
       Pursuant to the requirements of the Securities Act of 1933, the Registrant
  certifies that it has reasonable grounds to believe that it meets all of the
  requirements for filing on Form S-8 and has duly caused this registration
  statement on Form S-8 to be signed on its behalf by the undersigned, thereunto
  duly authorized, in the City of Boston, The Commonwealth of Massachusetts, on
  this 15th day of November, 1994.
  
                                        UST CORP.
  
                                        By /s/ Neal F. Finnegan
                                           -------------------------------------
                                           Neal F. Finnegan
                                           President and Chief Executive Officer
  
                                POWER OF ATTORNEY
  
       Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.  Each person whose signature appears
  below hereby authorizes and constitutes Eric R. Fischer, Esq. and Neal F.
  Finnegan, and each of them singly, his true and lawful attorneys with full
  power to them, and each of them singly, to sign for him and in his name in the
  capacities indicated below any and all amendments (including post-effective
  amendments) to this Registration Statement and to file the same, with exhibits
  thereto, and other documents in connection therewith, and he hereby ratifies
  and confirms his signature as it may be signed by said attorneys, or any of
  them, to any and all such amendments.
  SIGNATURE                          CAPACITY IN WHICH SIGNED             DATE
  - ---------                          ------------------------             ----
  /s/ Neal F. Finnegan               President, Chief Executive           November 15, 1994
  - -----------------------            Officer and Director (principal
  Neal F. Finnegan                   executive officer)
  
  /s/ James K. Hunt                  Executive Vice President,            November 15, 1994
  - -----------------------            Treasurer and Chief Financial
  James K. Hunt                      Officer (principal financial
                                     officer and principal accounting
                                     officer)
  
  /s/ Eric R. Fischer                Executive Vice President,            November 15, 1994
  - -----------------------            General Counsel and Clerk
  Eric R. Fischer
  
  /s/ William Schwartz               Vice Chairman and Director           November 15, 1994
  - -----------------------
  William Schwartz
  
  /s/ Domenic Colasacco              Executive Vice President and         November 15, 1994
  - -----------------------            Director
  Domenic Colasacco
  4
  /s/ James M. Breiner               Director                                    November 15, 1994
  - --------------------------         
  James M. Breiner
  
  /s/ Robert L. Culver               Director                                    November 15, 1994
  - --------------------------
  Robert L. Culver
  
  /s/ Walter A. Guleserian           Director                                    November 15, 1994
  - --------------------------
  Walter A. Guleserian
  
  /s/ Wallace M. Haselton            Director                                    November 15, 1994
  - --------------------------
  Wallace M. Haselton
  
  /s/ Francis X. Messina             Director                                    November 15, 1994
  - --------------------------
  Francis X. Messina
  
  /s/ Gerald M. Ridge                Director                                    November 15, 1994
  - --------------------------
  Gerald M. Ridge
  
  /s/ Samuel B. Sheldon              Director                                    November 15, 1994
  - --------------------------
  Samuel B. Sheldon
  
  /s/ James V. Sidell                Director                                    November 15, 1994
  - --------------------------
  James V. Sidell
  
  /s/ Paul D. Slater                 Director                                    November 15, 1994
  - --------------------------
  Paul D. Slater
  
  /s/ Michael D. Verrochi            Director                                    November 15, 1994
  - --------------------------
  Michael D. Verrochi
  5
                                  EXHIBIT INDEX
  Number                         Title of Exhibit                         Page
  - ------                         ----------------                         ----
  4.1                UST Corp. Stock Compensation Plan, as
                      amended and restated on November 15, 1994
  
   5.1                Opinion of Eric R. Fischer, Esq.
  
   23.1               Consent of Arthur Andersen LLP
  
   23.2               Consent of Eric R. Fischer, Esq. (contained in
                      the opinion filed as Exhibit 5.1 hereto).
  
   24                 Powers of Attorney (included in signature
                      page hereto).