content: <PAGE>   1
       As filed with the Securities and Exchange Commission on July 21, 2000
  
                                                       REGISTRATION NO. 333 -
  ================================================================================
  
                                    UNITED STATES
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                                  ---------------
  
                                      FORM S-8
                               REGISTRATION STATEMENT
                                      UNDER THE
                               SECURITIES ACT OF 1933
  
                                  ---------------
  
                               BAYCORP HOLDINGS, LTD.
               (Exact name of Registrant as specified in its charter)
  
             DELAWARE                                   02-0488443
  (State or other jurisdiction                       (I.R.S. Employer
  of incorporation or organization)                  Identification No.)
  
       20 INTERNATIONAL DRIVE, SUITE 301, PORTSMOUTH, NEW HAMPSHIRE 03801-6809
                 (Address of Principal Executive Offices) (Zip Code)
  
                               1996 STOCK OPTION PLAN
                              (Full title of the plan)
  
                                FRANK W. GETMAN, JR.
                        PRESIDENT AND CHIEF EXECUTIVE OFFICER
                               BAYCORP HOLDINGS, LTD.
                          20 INTERNATIONAL DRIVE, SUITE 301
                        PORTSMOUTH, NEW HAMPSHIRE 03801-6809
                       (Name and address of agent for service)
  
                                   (603) 431-6600
            (Telephone number, including area code, of agent for service)
  
                                  ---------------
  
                           CALCULATION OF REGISTRATION FEE
  
  <TABLE>
  <CAPTION>
  ===================================================================================================================================
                                                                PROPOSED                    PROPOSED
                                                                MAXIMUM                     MAXIMUM
             TITLE OF                   AMOUNT TO BE         OFFERING PRICE                AGGREGATE                   AMOUNT OF
   SECURITIES TO BE REGISTERED         REGISTERED(1)          PER SHARE(2)             OFFERING PRICE(2)            REGISTRATION FEE
  ----------------------------         -------------         --------------            -----------------            ----------------
  <S>                              <C>                   <C>                       <C>                          <C>
  
                                          251,817               $8.17                       $2,057,345                   $544
   Common Stock, $.01 par value            46,683               $8.47                       $  395,405                   $105
                                          -------                                                                        ----
                                          298,500                                                                        $649
  ===================================================================================================================================
  </TABLE>
  
  (1)  The number of shares of common stock, par value $.01 per share ("Common
       Stock"), stated above consists of the aggregate number of additional shares
       not previously registered which may be sold upon the exercise of options
       which have been granted and/or may hereafter be granted under the BayCorp
       Holdings, Ltd. 1996 Stock Option Plan, as amended (the "1996 Option Plan").
       The maximum number of shares which may be sold upon the exercise of such
       options granted under the 1996 Option Plan is subject to adjustment in
       accordance with certain anti-dilution and other provisions of said 1996
       Option Plan. Accordingly, pursuant to Rule 416 under the Securities Act of
       1933, as amended (the "Securities Act"), this Registration Statement
       covers, in addition to the number of shares stated above, an indeterminate
       number of shares which may be subject to grant or otherwise issuable after
       the operation of any such anti-dilution and other provisions.
  
  (2)  This calculation is made solely for the purpose of determining the
       registration fee pursuant to the provisions of Rule 457(h) under the
       Securities Act as follows: (i) in the case of shares of Common Stock which
       may be purchased upon exercise of outstanding options, the fee is
       calculated on the basis of the average price at which the options may be
       exercised; and (ii) in the case of shares of Common Stock for which options
       have not yet been granted and the option price of which is therefore
       unknown, the fee is calculated on the basis of the average of the high and
       low sale prices per share of the Common Stock on The American Stock
       Exchange ("AMEX") as of a date (July 19, 2000) within 5 business days prior
       to filing this Registration Statement.
  
  
  
  <PAGE>   2
  
  
       This registration statement on Form S-8 is being filed for the purpose of
  registering an additional 298,500 shares of BayCorp Holdings, Ltd. Common Stock
  to be issued pursuant to the 1996 Option Plan.
  
       This Registration Statement on Form S-8 incorporates by reference the
  contents of the Registration Statement on Form S-8 (File No. 333-24269), filed
  by the Registrant on March 31, 1997, relating to the Registrant's 1996 Stock
  Option Plan, with such modifications as are set forth below.
  
  
  ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
       The validity of the issuance of the shares of Common Stock registered under
  this Registration Statement has been passed upon for the Company by Mintz,
  Levin, Cohn, Ferris, Glovsky and Popeo, P.C. of Boston, Massachusetts.
  
  
  <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 to be signed on its behalf by the undersigned, thereunto duly
  authorized, in Portsmouth, New Hampshire, on July 21, 2000.
  
                                         BAYCORP HOLDINGS, LTD.
  
  
  
                                         By  /s/ Frank W. Getman, Jr.
                                            ---------------------------------
                                            Frank W. Getman, Jr.
                                            President and Chief Executive Officer
  
       Each person whose signature appears below constitutes and appoints Frank W.
  Getman, Jr. and Patrycia Barnard and each of them singly, his true and lawful
  attorneys-in-fact and agents, with full power of substitution and resubstitution
  in each of them, for him and in his name, place and stead, and in any and all
  capacities, to sign any and all amendments (including post-effective amendments)
  to this Registration Statement on Form S-8 of BayCorp Holdings, Ltd. and to file
  the same, with all exhibits thereto and other documents in connection therewith,
  with the Securities and Exchange Commission, granting unto said
  attorneys-in-fact and agents, and each of them, full power and authority to do
  and perform each and every act and thing requisite or necessary to be done in or
  about the premises, as full to all intents and purposes as he might or could do
  in person, hereby ratifying and confirming all that said attorneys-in-fact and
  agents or any of them or their or his substitute or substitutes may lawfully do
  or cause to be done by virtue hereof.
  
       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.
  
  <TABLE>
  <CAPTION>
  
            SIGNATURE                         TITLE                                    DATE
            ---------                         -----                                    ----
  <S>                           <C>                                            <C>
  
  /s/ Frank W. Getman, Jr.         President, Chief Executive Officer,             July 21, 2000
  ----------------------------     and Director
  Frank W. Getman, Jr.             (principal executive, financial,
                                   and accounting officer)
  
  
  /s/ Stanley I. Garnett           Director                                        July 21, 2000
  ----------------------------
  Stanley I. Garnett
  
  
  /s/ Michael R. Latina            Director                                        July 21, 2000
  ----------------------------
  Michael R. Latina
  
  </TABLE>
  
  
  
  <PAGE>   4
  <TABLE>
  <CAPTION>
  
            SIGNATURE                         TITLE                                    DATE
            ---------                         -----                                    ----
  <S>                           <C>                                            <C>
  
                                  Director
  ----------------------------
  Lawrence M. Robbins
  
  
  /s/ John A. Tillinghast         Director                                        July 21, 2000
  ----------------------------
  John A. Tillinghast
  
  /s/ Alexander Ellis             Director                                        July 21, 2000
  ----------------------------
  Alexander Ellis
  </TABLE>
  
  
  
  <PAGE>   5
  
  
  
                               BAYCORP HOLDINGS, LTD.
  
                            INDEX TO EXHIBITS FILED WITH
                           FORM S-8 REGISTRATION STATEMENT
  
  
  EXHIBIT
  NUMBER     DESCRIPTION
  -------    -----------
  
  4.1        Certificate of Incorporation of BayCorp Holdings, Ltd.(1)
  
  4.2        By-Laws of BayCorp Holdings, Ltd.(1)
  
  4.3        Form of Common Stock Certificate.(2)
  
  5          Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as
             to the legality of shares being registered.
  
  23.1       Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
             (included in opinion of counsel filed as Exhibit 5).
  
  23.2       Consent of Arthur Andersen LLP.
  
  24         Power of Attorney to file future amendments (set forth on the
             signature page of this Registration Statement).
  
  99         BayCorp Holdings, Ltd. 1996 Stock Option Plan, as amended.
  
  
  ------------------
  
  (1)  Filed as an Exhibit to the Registration Statement on Form S-4 of BayCorp
       Holdings, Ltd. (Registration Statement 333-3362) filed on July 12, 1996 and
       incorporated herein by reference.
  
  (2)  Filed as an Exhibit 4.3 to the Registration Statement on Form S-8 of
       BayCorp Holdings, Ltd. (Registration Statement 333-24269) filed on March
       31, 1997 and incorporated herein by reference.
metadata_documents: [{"type": "S-8", "sequence": "1", "filename": "s-8.txt", "description": "BAYCORP HOLDINGS, LTD.", "secsgml_size_bytes": 10839}]
metadata_filer: {"company-data": {"conformed-name": "BAYCORP HOLDINGS LTD", "cik": "0001012127", "assigned-sic": "4911", "irs-number": "020488443", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-42016", "film-number": "676985"}, "business-address": {"street1": "20 INTERNATIONAL DR", "street2": "STE 301", "city": "PORTSMOUTH", "state": "NH", "zip": "03801-6809", "phone": "6034316600"}, "mail-address": {"street1": "COCHECO FALLS MILLWORKS", "street2": "100 MAIN ST STE 201", "city": "DOVER", "state": "NH", "zip": "03820"}, "former-company": {"former-conformed-name": "GREAT BAY HOLDINGS CORP", "date-changed": "19960424"}}
text: 1
       As filed with the Securities and Exchange Commission on July 21, 2000
  
                                                       REGISTRATION NO. 333 -
  ================================================================================
  
                                    UNITED STATES
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                                  ---------------
  
                                      FORM S-8
                               REGISTRATION STATEMENT
                                      UNDER THE
                               SECURITIES ACT OF 1933
  
                                  ---------------
  
                               BAYCORP HOLDINGS, LTD.
               (Exact name of Registrant as specified in its charter)
  
             DELAWARE                                   02-0488443
  (State or other jurisdiction                       (I.R.S. Employer
  of incorporation or organization)                  Identification No.)
  
       20 INTERNATIONAL DRIVE, SUITE 301, PORTSMOUTH, NEW HAMPSHIRE 03801-6809
                 (Address of Principal Executive Offices) (Zip Code)
  
                               1996 STOCK OPTION PLAN
                              (Full title of the plan)
  
                                FRANK W. GETMAN, JR.
                        PRESIDENT AND CHIEF EXECUTIVE OFFICER
                               BAYCORP HOLDINGS, LTD.
                          20 INTERNATIONAL DRIVE, SUITE 301
                        PORTSMOUTH, NEW HAMPSHIRE 03801-6809
                       (Name and address of agent for service)
  
                                   (603) 431-6600
            (Telephone number, including area code, of agent for service)
  
                                  ---------------
  
                           CALCULATION OF REGISTRATION FEE
  ===================================================================================================================================
                                                                PROPOSED                    PROPOSED
                                                                MAXIMUM                     MAXIMUM
             TITLE OF                   AMOUNT TO BE         OFFERING PRICE                AGGREGATE                   AMOUNT OF
   SECURITIES TO BE REGISTERED         REGISTERED(1)          PER SHARE(2)             OFFERING PRICE(2)            REGISTRATION FEE
  ----------------------------         -------------         --------------            -----------------            ----------------
  251,817               $8.17                       $2,057,345                   $544
   Common Stock, $.01 par value            46,683               $8.47                       $  395,405                   $105
                                          -------                                                                        ----
                                          298,500                                                                        $649
  ===================================================================================================================================
  (1)  The number of shares of common stock, par value $.01 per share ("Common
       Stock"), stated above consists of the aggregate number of additional shares
       not previously registered which may be sold upon the exercise of options
       which have been granted and/or may hereafter be granted under the BayCorp
       Holdings, Ltd. 1996 Stock Option Plan, as amended (the "1996 Option Plan").
       The maximum number of shares which may be sold upon the exercise of such
       options granted under the 1996 Option Plan is subject to adjustment in
       accordance with certain anti-dilution and other provisions of said 1996
       Option Plan. Accordingly, pursuant to Rule 416 under the Securities Act of
       1933, as amended (the "Securities Act"), this Registration Statement
       covers, in addition to the number of shares stated above, an indeterminate
       number of shares which may be subject to grant or otherwise issuable after
       the operation of any such anti-dilution and other provisions.
  
  (2)  This calculation is made solely for the purpose of determining the
       registration fee pursuant to the provisions of Rule 457(h) under the
       Securities Act as follows: (i) in the case of shares of Common Stock which
       may be purchased upon exercise of outstanding options, the fee is
       calculated on the basis of the average price at which the options may be
       exercised; and (ii) in the case of shares of Common Stock for which options
       have not yet been granted and the option price of which is therefore
       unknown, the fee is calculated on the basis of the average of the high and
       low sale prices per share of the Common Stock on The American Stock
       Exchange ("AMEX") as of a date (July 19, 2000) within 5 business days prior
       to filing this Registration Statement.
  2
  
       This registration statement on Form S-8 is being filed for the purpose of
  registering an additional 298,500 shares of BayCorp Holdings, Ltd. Common Stock
  to be issued pursuant to the 1996 Option Plan.
  
       This Registration Statement on Form S-8 incorporates by reference the
  contents of the Registration Statement on Form S-8 (File No. 333-24269), filed
  by the Registrant on March 31, 1997, relating to the Registrant's 1996 Stock
  Option Plan, with such modifications as are set forth below.
  
  ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
       The validity of the issuance of the shares of Common Stock registered under
  this Registration Statement has been passed upon for the Company by Mintz,
  Levin, Cohn, Ferris, Glovsky and Popeo, P.C. of Boston, Massachusetts.
  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 to be signed on its behalf by the undersigned, thereunto duly
  authorized, in Portsmouth, New Hampshire, on July 21, 2000.
  
                                         BAYCORP HOLDINGS, LTD.
  
                                         By  /s/ Frank W. Getman, Jr.
                                            ---------------------------------
                                            Frank W. Getman, Jr.
                                            President and Chief Executive Officer
  
       Each person whose signature appears below constitutes and appoints Frank W.
  Getman, Jr. and Patrycia Barnard and each of them singly, his true and lawful
  attorneys-in-fact and agents, with full power of substitution and resubstitution
  in each of them, for him and in his name, place and stead, and in any and all
  capacities, to sign any and all amendments (including post-effective amendments)
  to this Registration Statement on Form S-8 of BayCorp Holdings, Ltd. and to file
  the same, with all exhibits thereto and other documents in connection therewith,
  with the Securities and Exchange Commission, granting unto said
  attorneys-in-fact and agents, and each of them, full power and authority to do
  and perform each and every act and thing requisite or necessary to be done in or
  about the premises, as full to all intents and purposes as he might or could do
  in person, hereby ratifying and confirming all that said attorneys-in-fact and
  agents or any of them or their or his substitute or substitutes may lawfully do
  or cause to be done by virtue hereof.
  
       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.
  SIGNATURE                         TITLE                                    DATE
            ---------                         -----                                    ----
  /s/ Frank W. Getman, Jr.         President, Chief Executive Officer,             July 21, 2000
  ----------------------------     and Director
  Frank W. Getman, Jr.             (principal executive, financial,
                                   and accounting officer)
  
  /s/ Stanley I. Garnett           Director                                        July 21, 2000
  ----------------------------
  Stanley I. Garnett
  
  /s/ Michael R. Latina            Director                                        July 21, 2000
  ----------------------------
  Michael R. Latina
  4
  SIGNATURE                         TITLE                                    DATE
            ---------                         -----                                    ----
  Director
  ----------------------------
  Lawrence M. Robbins
  
  /s/ John A. Tillinghast         Director                                        July 21, 2000
  ----------------------------
  John A. Tillinghast
  
  /s/ Alexander Ellis             Director                                        July 21, 2000
  ----------------------------
  Alexander Ellis
  5
  
                               BAYCORP HOLDINGS, LTD.
  
                            INDEX TO EXHIBITS FILED WITH
                           FORM S-8 REGISTRATION STATEMENT
  
  EXHIBIT
  NUMBER     DESCRIPTION
  -------    -----------
  
  4.1        Certificate of Incorporation of BayCorp Holdings, Ltd.(1)
  
  4.2        By-Laws of BayCorp Holdings, Ltd.(1)
  
  4.3        Form of Common Stock Certificate.(2)
  
  5          Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as
             to the legality of shares being registered.
  
  23.1       Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
             (included in opinion of counsel filed as Exhibit 5).
  
  23.2       Consent of Arthur Andersen LLP.
  
  24         Power of Attorney to file future amendments (set forth on the
             signature page of this Registration Statement).
  
  99         BayCorp Holdings, Ltd. 1996 Stock Option Plan, as amended.
  
  ------------------
  
  (1)  Filed as an Exhibit to the Registration Statement on Form S-4 of BayCorp
       Holdings, Ltd. (Registration Statement 333-3362) filed on July 12, 1996 and
       incorporated herein by reference.
  
  (2)  Filed as an Exhibit 4.3 to the Registration Statement on Form S-8 of
       BayCorp Holdings, Ltd. (Registration Statement 333-24269) filed on March
       31, 1997 and incorporated herein by reference.