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)       December 7, 1999
                                                 -------------------------------


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


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


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


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


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




Item 5. Other Events.

         On December 7, 1999, NBT Bancorp Inc., a Delaware  corporation ("NBT"),
and Pioneer American Holding Company Corp., a Pennsylvania corporation ("Pioneer
American"),  announced  that  they had  entered  into an  Agreement  and Plan of
Merger, dated as of December 7, 1999 (the "Merger Agreement").

         Pursuant to the Merger Agreement,  Pioneer American will merge with and
into NBT, with NBT being the surviving corporation (the "Merger").  Shareholders
of Pioneer  American  will  receive a fixed ratio of 1.805  shares of NBT common
stock for each share exchanged.  Based on the December 7, 1999, closing price of
NBT common stock on the Nasdaq National Market, NBT will issue approximately 5.2
million shares and share equivalents in exchange for all of the Pioneer American
common stock and share  equivalents  outstanding.  Pioneer American has provided
NBT an option to acquire up to 569,997 shares of Pioneer American's common stock
(equivalent to 19.9% of Pioneer  American's common stock currently  outstanding)
exercisable in the event of certain  circumstances  involving  transactions with
third parties,  acts of third parties, or break-up of the Merger Agreement.  The
Merger is subject to the approval of each company's  shareholders and of banking
regulators. The Merger is expected to close in the second quarter of 2000 and is
intended  to be  accounted  for as a  pooling-of-interests  and to  qualify as a
tax-free  exchange for Lake Ariel  shareholders.  The  transaction  is valued at
$84.48 million or $29.33 per share for the  outstanding  common stock of Pioneer
American.

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 December 7, 1999, by
                  and among NBT  Bancorp  Inc.,  Levon  Acquisition  Company and
                  Pioneer American Holding Company Corp. *



2.2               The  Directors'  Agreement,  dated as of December 7, 1999,  is
                  part of the  Agreement  and Plan of Merger,  which is filed as
                  Exhibit 2.1 above.

2.3               Stock Option Agreement, dated December 7, 1999, by and between
                  Pioneer  American  Holding  Company  Corp. as "Issuer" and NBT
                  Bancorp Inc. as "Grantee." *

2.4               Form of Employment Agreement with John W. Reuther. *

2.5               Form of Change-in-Control Agreement. *

2.6               Shareholders Voting Agreement. *

99.1              Press release, dated December 8, 1999.

*    Incorporated  by  reference  to the  corresponding  exhibit  number  in the
Registrant's  Schedule 13D filed by the  Registrant on December 16, 1999    with
respect to Pioneer American Holding Company Corp., File No. 0-14506.


                                    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:  December 16, 1999.





                                  EXHIBIT INDEX

99.1              Press release, dated December 8, 1999.
                                  EXHIBIT 99.1

                                  PRESS RELEASE



 NBT Bancorp Inc. Announces  Agreement of Merger With Pioneer  American  Holding
Company Corp.

NORWICH, N.Y., and CARBONDALE,  Pa., Dec. 8 -- NBT Bancorp Inc. (Nasdaq:  NBTB),
the parent company of NBT Bank, N.A., and Pioneer American Holding Company Corp.
(OTC Bulletin  Board:  PAHC.OB),  the parent  company of Pioneer  American Bank,
N.A.,  announced  today that they have entered  into a  definitive  agreement of
merger. The merger is subject to the approval of each company's shareholders and
of banking regulators.

The merger is expected to close in the second quarter of 2000 and is intended to
be accounted for as a pooling-of-interests and to qualify as a tax-free exchange
for Pioneer American shareholders. Shareholders of Pioneer American will receive
a fixed ratio of 1.805  shares of NBT Bancorp  Inc.  common stock for each share
exchanged.  NBT Bancorp Inc. (NBT) will issue  approximately  5.2 million shares
and share  equivalents in exchange for all of the Pioneer  American common stock
and share equivalents  outstanding.  The transaction is valued at $84.48 million
or $29.33  per share  for the  outstanding  common  shares of  Pioneer  American
Holding Company Corp.  (Pioneer  American) based on the December 7 closing price
of $16.25 for NBT common stock.  Pioneer  American has provided NBT an option to
acquire up to 569,997 shares of Pioneer  American's  common stock (equivalent to
19.9% of Pioneer American's common stock currently  outstanding)  exercisable in
the event of certain  circumstances  involving  transactions with third parties,
acts of third parties, or break-up of the merger agreement.

On August 16, 1999,  NBT and Lake Ariel Bancorp Inc.  (Nasdaq:  LABN) the parent
company of LA Bank,  N.A.  announced an agreement  of merger.  Pioneer  American
Bank,  N.A. will  ultimately be merged  together with LA Bank, with the combined
entity  becoming  the  largest  community  bank  headquartered  in  northeastern
Pennsylvania.  NBT Bancorp President and CEO, Daryl R. Forsythe, states, "We are
extremely  pleased to include  Pioneer  American  into our plans to expand  into
Pennsylvania  through the  acquisition of these two strong  growing  banks.  Our
abilities to make the  necessary  cost savings and initiate  effective,  revenue
growth plans, thus making the transactions accretive, are measurably enhanced by
combining  the two banks.  Pioneer  American,  like LA Bank,  is a bank known in
northeastern  Pennsylvania for its community service,  much as NBT Bank is known
in its New York market areas.  Pioneer Bank and LA Bank have aggressively  grown
their franchises over the past five years, and our combined strengths of capital
and management will encourage  continued growth. We expect the transaction to be
accretive  to  earnings,  shortly  after the first full year of  operation  as a
combined entity."

John W. Reuther, President and CEO of Pioneer American Holding Company Corp. and
Pioneer American Bank,  N.A., adds, "This is a wonderful  opportunity for us. It
allows Pioneer  American and LA Bank to combine  resources,  to maintain a local
decision  making  presence and become a major  component of NBT's plans to build
the  premier  community  bank in this  region.  We  will



be able to offer our customers  expanded lending  capabilities,  trust services,
venture capital, and other products, which should aid in future growth. NBT Bank
and LA Bank are strong performing,  well managed companies,  and we look forward
to sharing their resources."

John G.  Martines,  President and CEO of LA Bank notes,  "The  transaction  will
position us to be the leading financial institution in northeastern Pennsylvania
with 60 ATM outlets and  conveniently  located  branches  throughout  our served
markets. Going forward, the new franchise that will be established will carry us
confidently  into the new  millennium and allow us to better serve the residents
of northeastern Pennsylvania."

NBT Bank, N.A., the wholly owned subsidiary of NBT, is a full service commercial
bank with total assets of over $1.375 billion.  The Bank has 36 branches in nine
counties in central New York. NBT and NBT Bank are headquartered in Norwich, NY,
where the Bank was formed in 1856. NBT has approximately  3,700 shareholders and
approximately 12.4 million common shares outstanding.

Pioneer American Bank, N.A., the wholly owned subsidiary of Pioneer American, is
a full service  commercial bank with total assets of approximately $420 million.
The Bank has 18 branches in five counties in northeastern Pennsylvania.  Pioneer
American and the Bank are  headquartered  in Carbondale,  Pennsylvania.  Pioneer
American has  approximately  1,460  shareholders and  approximately  2.9 million
common shares outstanding.

Lake Ariel's wholly owned  subsidiary,  LA Bank,  N.A., has  approximately  $550
million in assets.  The Bank has 22 branch  offices  serving  five  counties  in
northeastern  Pennsylvania.  The Company,  which is headquartered in Lake Ariel,
Pennsylvania,  has  approximately  1,400  shareholders  and  approximately  4.85
million common shares  outstanding.  The Company's  financial center,  including
executive offices, is in Scranton, Pennsylvania.

The  combined  company,  NBT Bancorp  Inc.,  with pro forma  assets of over $2.3
billion will be headed by President  and CEO Daryl R.  Forsythe.  John  Martines
will become the Chairman and CEO of the Pennsylvania  bank and John Reuther will
become  President  and  Chief  Operating  Officer  of that  bank.  Both  will be
instrumental  in the  combined  efforts  to  serve  the  customers  and grow the
franchise in northeastern Pennsylvania.

Forward-Looking Information

This news release  contains  statements  regarding the projected  performance of
NBT,  Pioneer  American,  and Lake Ariel on a stand-alone and pro forma combined
basis.  These  statements  constitute  forward-looking  information  within  the
meaning of the Private Securities  Litigation Reform Act of 1995. Actual results
may differ materially from the projections  discussed in this release since such
projections  involve  significant  risks and  uncertainties.  Factors that might
cause such  differences  include,  but are not limited to: the timing of closing
the proposed  mergers  being  delayed;  competitive  pressures  among  financial
institutions increasing significantly; economic conditions, either nationally or
locally in areas in which NBT,  Pioneer  American and Lake Ariel  conduct  their
operations, being less favorable than expected; the cost and efforts required to
integrate  aspects of the operations of the companies  being more difficult than



expected;  expected  cost  savings  from the  proposed  mergers  not being fully
realized or realized within the expected time frames;  legislation or regulatory
changes which  adversely  affect the ability of the combined  company to conduct
its current or future  operation;  and the impact of the  transition to the year
2000 on the  operation of NBT,  Pioneer  American,  Lake Ariel,  or the combined
company.  NBT, Pioneer American and Lake Ariel disclaim any obligation to update
any such factors or to publicly  announce the results of any revisions to any of
the  forward-looking  statements  included  herein to reflect  future  events or
developments.

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