SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                              ---------------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


Date  of  Report   (Date  of   earliest   event   reported)   April   19,   2000
                                                             -------------------

                                NBT Bancorp Inc.
      --------------------------------------------------------------------
                  (Exact Name of Registrant as Specified in Charter)

         Delaware                       0-14703               16-1268674
-------------------------------------------------------------------------------
   (State or Other Jurisdiction      (Commission            (IRS Employer
         of Incorporation)           File Number)        Identification Number)

   52 South Broad Street, Norwich, New York                13815
-------------------------------------------------------------------------------
(Address of Principal Executive Office)                 (Zip Code)

Registrant's telephone number, including area code        607/337-2265
                                                   -------------------

                                       N/A
-------------------------------------------------------------------------------
          (Former Name or Former Address, if Changed Since Last Report)

<PAGE>

Item 5. Other Events.

         On April 20, 2000,  NBT Bancorp Inc., a Delaware  corporation  ("NBT"),
and BSB Bancorp,  Inc., a Delaware corporation ("BSB"),  announced that they had
entered  into an Agreement  and Plan of Merger,  dated as of April 19, 2000 (the
"Merger Agreement").

         Pursuant  to  the  Merger  Agreement,  BSB  and  NBT  will  merge  (the
"Merger"), with NBT being the surviving corporation, to create a holding company
with  assets  of $4.7  billion.  A new name  will be  chosen  for the  surviving
corporation  before the Merger  occurs.  Stockholders  of BSB will  receive  two
shares of NBT  common  stock for each  share  exchanged.  Based on the April 19,
2000,  closing  price of NBT common  stock on the Nasdaq  National  Market,  the
transaction  is valued at $251  million or $24.00 per share for the  outstanding
common  stock of BSB.  The Merger,  which has been  unanimously  approved by the
boards of directors of NBT and BSB, is subject to the approval of each company's
stockholders and of banking  regulators.  The Merger is expected to close in the
fourth   quarter  of  2000  and  is   intended   to  be   accounted   for  as  a
pooling-of-interests and to qualify as a tax-free exchange for BSB stockholders.

         BSB has  provided  NBT an option to acquire a number of shares of BSB's
common stock equal to 19.9% of BSB's common  stock  outstanding  as of the first
date the option becomes  exercisable;  the option is exercisable in the event of
certain circumstances  involving  transactions with third parties, acts of third
parties, or break-up of the Merger Agreement.  NBT has provided BSB an option to
acquire a number of shares of NBT's  common stock equal to 19.9% of NBT's common
stock  outstanding  as of the first date the  option  becomes  exercisable;  the
option  is  exercisable  in  the  event  of  certain   circumstances   involving
transactions  with third  parties,  acts of third  parties,  or  break-up of the
Merger Agreement.

         The combined  company will have a 15-seat board of directors which will
be made up of seven  directors  from  BSB and six  from NBT plus one from  NBT's
newly acquired Lake Ariel  Bancorp,  Inc.  Pennsylvania  subsidiary and one from
Pioneer  American  Holding Company Corp.  ("Pioneer  American"),  subject to the
closing of the merger of NBT and Pioneer American. If the merger between NBT and
Pioneer American is not consummated before the effective time of the Merger, the
board of directors of the combined company will consist of 13 directors,  six of
whom will be designated  by the BSB board of directors,  six by the NBT board of
directors,  and one  former  Lake Ariel  board  member who is serving on the NBT
board at the effective  time of the Merger.  This former Lake Ariel board member
will be  designated  by the NBT  board.  Common  stockholders  of NBT will  have
ownership of approximately 53 percent of the combined company while BSB's common
stockholders will own approximately 47 percent,  assuming  consummation of NBT's
previously announced agreement to merge with Pioneer American.

<PAGE>

         Immediately  following the Merger,  NBT's and BSB's  principal  banking
subsidiaries,  NBT Bank, N.A. and BSB Bank & Trust Company, will merge, with NBT
Bank being the resulting  bank in the bank merger,  to create one of the largest
independent  community  banks in  upstate  New York.  The new bank will serve 12
counties  from more than 55 offices and over 100 ATMs. A new name will be chosen
for the resulting bank prior to the Merger. The combined company will have three
direct  operating  subsidiaries  including two  community  banks and a financial
services company.

         Daryl R. Forsythe,  president and chief executive  officer of NBT, will
become the  chairman,  president  and chief  executive  officer of the  combined
company and William C. Craine, chairman of BSB, will become the vice chairman of
the  combined  company  and  chairman  of the  executive  committee.  NBT Bank's
president  and chief  operating  officer,  Martin A.  Dietrich,  will become the
president and chief operating officer of the company's New York bank. Michael J.
Chewens, executive vice president and chief financial officer of NBT, will serve
as chief  financial  officer  for the  combined  company.  Other  members of the
executive management teams at NBT and BSB will retain key roles including: Glenn
R. Small and John R.  Bradley,  executive  vice  presidents of lending and Larry
Denniston, senior vice president and corporate secretary.

         The  corporate  offices  of the  combined  company  will be  located in
Binghamton.  Other major bank  functions  will be conducted  from the  company's
Norwich, Binghamton and Scranton locations following the Merger.

Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits.


                  (a) Not Applicable.

                  (b) Not Applicable.

                  (c) Exhibits.


         The  following   exhibits  are  filed  with  this  Current   Report  or
incorporated by reference into this Current Report on Form 8-K:


Exhibit
Number            Description
------            -----------

2.1               Agreement and Plan of  Merger, dated as of April 19, 2000, by
                  and between NBT Bancorp Inc. and BSB Bancorp, Inc.


<PAGE>


2.2               Form of Plan of Merger  between  BSB Bank & Trust  Company and
                  NBT Bank, National  Association,  is part of the Agreement and
                  Plan of Merger, which is filed as Exhibit 2.1 above.

2.3               The BSB Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.4               The NBT Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.5               BSB Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between BSB Bancorp,  Inc. as "Issuer" and NBT Bancorp Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

2.6               NBT Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between NBT Bancorp Inc. as "Issuer" and BSB Bancorp,  Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

99.1              Press release, dated April 20, 2000.


<PAGE>


                                    SIGNATURE

         Pursuant to the  requirements  of the Securities  Exchange Act of 1934,
the  Registrant  has duly  caused  this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                           NBT BANCORP INC.


                                           By:  /s/ Daryl R. Forsythe
                                                ---------------------
                                                Name: Daryl R. Forsythe
                                                Title: President and Chief
                                                Executive Officer

Date:  April 27, 2000



<PAGE>

                                  EXHIBIT INDEX
                                  -------------

2.1               Agreement  and Plan of Merger,  dated as of April 19, 2000, by
                  and between NBT Bancorp Inc. and BSB Bancorp, Inc.

2.2               Form of Plan of Merger  between  BSB Bank & Trust  Company and
                  NBT Bank, National  Association,  is part of the Agreement and
                  Plan of Merger, which is filed as Exhibit 2.1 above.

2.3               The BSB Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.4               The NBT Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.5               BSB Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between BSB Bancorp,  Inc. as "Issuer" and NBT Bancorp Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

2.6               NBT Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between NBT Bancorp Inc. as "Issuer" and BSB Bancorp,  Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

99.1              Press release, dated April 20, 2000.
[{"type": "8-K", "sequence": "1", "description": "FORM 8-K", "secsgml_size_bytes": 10467}]
{"company-data": {"conformed-name": "NBT BANCORP INC", "cik": "0000790359", "assigned-sic": "6021", "irs-number": "161268674", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-14703", "film-number": "611485"}, "business-address": {"street1": "52 S BROAD ST", "city": "NORWICH", "state": "NY", "zip": "13815", "phone": "6073372265"}, "mail-address": {"street1": "52 S. BROAD STREET", "city": "NORWICH", "state": "NY", "zip": "13815"}}
SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                              ---------------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

Date  of  Report   (Date  of   earliest   event   reported)   April   19,   2000
                                                             -------------------

                                NBT Bancorp Inc.
      --------------------------------------------------------------------
                  (Exact Name of Registrant as Specified in Charter)

         Delaware                       0-14703               16-1268674
-------------------------------------------------------------------------------
   (State or Other Jurisdiction      (Commission            (IRS Employer
         of Incorporation)           File Number)        Identification Number)

   52 South Broad Street, Norwich, New York                13815
-------------------------------------------------------------------------------
(Address of Principal Executive Office)                 (Zip Code)

Registrant's telephone number, including area code        607/337-2265
                                                   -------------------

                                       N/A
-------------------------------------------------------------------------------
          (Former Name or Former Address, if Changed Since Last Report)
Item 5. Other Events.

         On April 20, 2000,  NBT Bancorp Inc., a Delaware  corporation  ("NBT"),
and BSB Bancorp,  Inc., a Delaware corporation ("BSB"),  announced that they had
entered  into an Agreement  and Plan of Merger,  dated as of April 19, 2000 (the
"Merger Agreement").

         Pursuant  to  the  Merger  Agreement,  BSB  and  NBT  will  merge  (the
"Merger"), with NBT being the surviving corporation, to create a holding company
with  assets  of $4.7  billion.  A new name  will be  chosen  for the  surviving
corporation  before the Merger  occurs.  Stockholders  of BSB will  receive  two
shares of NBT  common  stock for each  share  exchanged.  Based on the April 19,
2000,  closing  price of NBT common  stock on the Nasdaq  National  Market,  the
transaction  is valued at $251  million or $24.00 per share for the  outstanding
common  stock of BSB.  The Merger,  which has been  unanimously  approved by the
boards of directors of NBT and BSB, is subject to the approval of each company's
stockholders and of banking  regulators.  The Merger is expected to close in the
fourth   quarter  of  2000  and  is   intended   to  be   accounted   for  as  a
pooling-of-interests and to qualify as a tax-free exchange for BSB stockholders.

         BSB has  provided  NBT an option to acquire a number of shares of BSB's
common stock equal to 19.9% of BSB's common  stock  outstanding  as of the first
date the option becomes  exercisable;  the option is exercisable in the event of
certain circumstances  involving  transactions with third parties, acts of third
parties, or break-up of the Merger Agreement.  NBT has provided BSB an option to
acquire a number of shares of NBT's  common stock equal to 19.9% of NBT's common
stock  outstanding  as of the first date the  option  becomes  exercisable;  the
option  is  exercisable  in  the  event  of  certain   circumstances   involving
transactions  with third  parties,  acts of third  parties,  or  break-up of the
Merger Agreement.

         The combined  company will have a 15-seat board of directors which will
be made up of seven  directors  from  BSB and six  from NBT plus one from  NBT's
newly acquired Lake Ariel  Bancorp,  Inc.  Pennsylvania  subsidiary and one from
Pioneer  American  Holding Company Corp.  ("Pioneer  American"),  subject to the
closing of the merger of NBT and Pioneer American. If the merger between NBT and
Pioneer American is not consummated before the effective time of the Merger, the
board of directors of the combined company will consist of 13 directors,  six of
whom will be designated  by the BSB board of directors,  six by the NBT board of
directors,  and one  former  Lake Ariel  board  member who is serving on the NBT
board at the effective  time of the Merger.  This former Lake Ariel board member
will be  designated  by the NBT  board.  Common  stockholders  of NBT will  have
ownership of approximately 53 percent of the combined company while BSB's common
stockholders will own approximately 47 percent,  assuming  consummation of NBT's
previously announced agreement to merge with Pioneer American.
Immediately  following the Merger,  NBT's and BSB's  principal  banking
subsidiaries,  NBT Bank, N.A. and BSB Bank & Trust Company, will merge, with NBT
Bank being the resulting  bank in the bank merger,  to create one of the largest
independent  community  banks in  upstate  New York.  The new bank will serve 12
counties  from more than 55 offices and over 100 ATMs. A new name will be chosen
for the resulting bank prior to the Merger. The combined company will have three
direct  operating  subsidiaries  including two  community  banks and a financial
services company.

         Daryl R. Forsythe,  president and chief executive  officer of NBT, will
become the  chairman,  president  and chief  executive  officer of the  combined
company and William C. Craine, chairman of BSB, will become the vice chairman of
the  combined  company  and  chairman  of the  executive  committee.  NBT Bank's
president  and chief  operating  officer,  Martin A.  Dietrich,  will become the
president and chief operating officer of the company's New York bank. Michael J.
Chewens, executive vice president and chief financial officer of NBT, will serve
as chief  financial  officer  for the  combined  company.  Other  members of the
executive management teams at NBT and BSB will retain key roles including: Glenn
R. Small and John R.  Bradley,  executive  vice  presidents of lending and Larry
Denniston, senior vice president and corporate secretary.

         The  corporate  offices  of the  combined  company  will be  located in
Binghamton.  Other major bank  functions  will be conducted  from the  company's
Norwich, Binghamton and Scranton locations following the Merger.

Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits.

                  (a) Not Applicable.

                  (b) Not Applicable.

                  (c) Exhibits.

         The  following   exhibits  are  filed  with  this  Current   Report  or
incorporated by reference into this Current Report on Form 8-K:

Exhibit
Number            Description
------            -----------

2.1               Agreement and Plan of  Merger, dated as of April 19, 2000, by
                  and between NBT Bancorp Inc. and BSB Bancorp, Inc.
2.2               Form of Plan of Merger  between  BSB Bank & Trust  Company and
                  NBT Bank, National  Association,  is part of the Agreement and
                  Plan of Merger, which is filed as Exhibit 2.1 above.

2.3               The BSB Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.4               The NBT Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.5               BSB Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between BSB Bancorp,  Inc. as "Issuer" and NBT Bancorp Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

2.6               NBT Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between NBT Bancorp Inc. as "Issuer" and BSB Bancorp,  Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

99.1              Press release, dated April 20, 2000.
SIGNATURE

         Pursuant to the  requirements  of the Securities  Exchange Act of 1934,
the  Registrant  has duly  caused  this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                           NBT BANCORP INC.

                                           By:  /s/ Daryl R. Forsythe
                                                ---------------------
                                                Name: Daryl R. Forsythe
                                                Title: President and Chief
                                                Executive Officer

Date:  April 27, 2000
EXHIBIT INDEX
                                  -------------

2.1               Agreement  and Plan of Merger,  dated as of April 19, 2000, by
                  and between NBT Bancorp Inc. and BSB Bancorp, Inc.

2.2               Form of Plan of Merger  between  BSB Bank & Trust  Company and
                  NBT Bank, National  Association,  is part of the Agreement and
                  Plan of Merger, which is filed as Exhibit 2.1 above.

2.3               The BSB Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.4               The NBT Stockholder Agreement,  dated as of April 19, 2000, is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.5               BSB Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between BSB Bancorp,  Inc. as "Issuer" and NBT Bancorp Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

2.6               NBT Stock  Option  Agreement,  dated  April 19,  2000,  by and
                  between NBT Bancorp Inc. as "Issuer" and BSB Bancorp,  Inc. as
                  "Grantee" is part of the Agreement  and Plan of Merger,  which
                  is filed as Exhibit 2.1 above.

99.1              Press release, dated April 20, 2000.