As filed with the Securities and Exchange Commission on June 27, 2000
                                                   Registration Number 333-XXXXX
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                   ----------

                                    FORM S-3


                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


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

                                    Delaware
- --------------------------------------------------------------------------------
         (State or Other Jurisdiction of Incorporation or Organization)

                                   16-1268674
- --------------------------------------------------------------------------------
                     (I.R.S. Employer Identification Number)

                              52 South Broad Street
                             Norwich, New York 13815
                                  607/337-2265
- --------------------------------------------------------------------------------
    (Address, Including Zip Code, and Telephone Number, Including Area Code,
                  of Registrant's Principal Executive Offices)

                                   Copies to:
Daryl R. Forsythe                           Brian D. Alprin, Esq.
President and Chief Executive Officer       Laurence S. Lese, Esq.
NBT Bancorp Inc.                            Duane, Morris & Heckscher LLP
52 South Broad Street                       1667 K Street, N.W., Suite 700
Norwich, New York 13815                     Washington, D.C. 20006-1608
607/337-2265                                202/776-7800

- -----------------------------------
(Name, Address, Including Zip Code,
and Telephone Number, Including
Area Code, of Agent For Service)

         Approximate  date of  commencement  of proposed sale to the public:  as
soon as practicable after effectiveness of the registration statement.

         If the only securities  being registered on this form are being offered
pursuant to dividend or interest  reinvestment plans, please check the following
box. [ ]

         If any of the  securities  being  registered  on  this  form  are to be
offered  on a  delayed  or  continuous  basis  pursuant  to Rule 415  under  the
Securities Act of 1933,  other than  securities  offered only in connection with
dividend or interest reinvestment plans, check the following box. [X]

         If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list  the  Securities  Act  registration  statement  number  of the  earlier
effective registration statement for the same offering. [ ]_____________

         If this  form is a  post-effective  amendment  filed  pursuant  to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act  registration   statement  number  of  the  earlier  effective  registration
statement for the same offering. [ ]_____________

         If delivery of the  prospectus  is expected to be made pursuant to Rule
434, please check the following box. [ ]


                         CALCULATION OF REGISTRATION FEE







====================================================================================================================================
                                                                                            Proposed Maximum
                                                                   Proposed Maximum        Aggregate Offering
                                                                  Aggregate Price per            Price                Amount of
   Title of Shares to Be Registered          Amount to Be               Unit(1)                                  Registration Fee(1)
                                              Registered
- ------------------------------------------------------------------------------------------------------------------------------------
                                                                                                           
common stock, $.01 par value                    420,989                    $10.5625              $4,446,697         $ 1,174
====================================================================================================================================



(1)      Pursuant to Rule 457(c),  the  registration  fee has been determined on
         the basis of the average of the high and low prices of NBT common stock
         as  reported on the Nasdaq  National  Market on June 26,  2000,  a date
         within five business days prior to the date of filing the  registration
         statement.

         THE REGISTRANT HEREBY AMENDS THIS  REGISTRATION  STATEMENT ON SUCH DATE
OR DATES AS MAY BE NECESSARY TO DELAY ITS  EFFECTIVE  DATE UNTIL THE  REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY  STATES THAT THIS REGISTRATION
STATEMENT SHALL  THEREAFTER  BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE  SECURITIES  ACT OF 1933 OR UNTIL THE  REGISTRATION  STATEMENT  SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION,  ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.



PROSPECTUS 420,989 SHARES COMMON STOCK ($.01 PAR VALUE PER SHARE) NBT BANCORP INC. This prospectus relates to the offering by a selling stockholder, David T. Griffith, for resale of 420,989 shares of common stock, $.01 par value per share of NBT Bancorp Inc., a Delaware corporation. This offering is not being underwritten. Mr. Griffith will receive the entire proceeds of any sales he is able to make of the shares, except for brokerage commissions and other costs he must incur in connection with his sales. We will receive no part of the proceeds of any sales made by Mr. Griffith. We have not previously registered any of Mr. Griffith's shares of our common stock prior to the filing of the Registration Statement of which this prospectus is a part. Our common stock is quoted on the Nasdaq National Market under the symbol "NBTB." On June __, 2000, the last reported sale price of our common stock was $XX.XX per share. Mr. Griffith may offer the shares for sale from time to time through broker-dealers on the Nasdaq National Market, or otherwise, at such prices as he is able to obtain at the time of each sale. Mr. Griffith and any broker executing selling orders on his behalf may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended. See "Plan of Distribution." We encourage you to read this prospectus carefully. This prospectus incorporates important business and financial information about us that is not included in or delivered with this document. See "Where You Can Find More Information" on page 2. NEITHER THE SEC NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THE NBT SHARES TO BE ISSUED UNDER THIS PROSPECTUS OR PASSED UPON THE ADEQUACY OR ACCURACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE. THE SHARES OF NBT COMMON STOCK OFFERED BY THIS PROSPECTUS ARE NOT SAVINGS ACCOUNTS, DEPOSITS OR OTHER OBLIGATIONS OF ANY BANK OR NON-BANK SUBSIDIARY OF ANY OF THE PARTIES. THE FDIC OR ANY OTHER GOVERNMENTAL AGENCY DOES NOT INSURE OR GUARANTEE ANY LOSS TO YOU OF YOUR INVESTMENT VALUE IN THE NBT COMMON STOCK. The date of this prospectus is June __, 2000

No person has been authorized to give any information or to make any representations other than those contained in or incorporated by reference in this prospectus in connection with the offering made by this prospectus, and, if given or made, such information or representations must not be relied upon as having been authorized by us, the selling stockholder or any other person. Neither the delivery of this prospectus nor any sale made under this prospectus shall, under any circumstances, create an implication that information in this prospectus is correct as of any time subsequent to the date of this prospectus or that there has been no change in our affairs since the date as of which information is given in this prospectus. This prospectus does not constitute an offer to sell or a solicitation of an offer to buy any security other than the securities covered by this prospectus, nor does it constitute an offer to or a solicitation of any person in any jurisdiction in which such offer or solicitation may not be lawfully made. TABLE OF CONTENTS Where You Can Find More Information ...................................... 2 NBT Bancorp Inc. SEC Filings (SEC File No. 0-14703) ..................... 3 NBT Bancorp Inc .......................................................... 3 Use of Proceeds .......................................................... 5 Price Range of Common Stock and Dividends ................................ 5 Selling Stockholder ...................................................... 6 Plan of Distribution ..................................................... 6 Description of NBT Capital Stock ......................................... 7 Legal Matters ............................................................ 8 Experts .................................................................. 8 Cautionary Statement Regarding Forward-Looking Statements ................ 9 Unaudited Pro Forma Condensed Combined Financial Statements .............. 10 Notes to Unaudited Pro Forma Condensed Combined Financial Statements ..... 17 WHERE YOU CAN FIND MORE INFORMATION We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any reports, statements or other information we file at the SEC's public reference room at 450 Fifth Street, N.W., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. Our SEC filings are also available to the public from commercial document retrieval services and at the web site maintained by the SEC at {http://www.sec.gov}. In addition, you may read and copy our SEC filings at the Nasdaq National Market, 1735 K Street, N.W., Washington, D.C. 20006-1500. Our Internet address is {www.nbtbank.com}. We have filed a registration statement on Form S-3 to register with the SEC our common stock being offered and sold by the selling stockholder, Mr. Griffith. This prospectus is a part of that registration statement. As allowed 2

by SEC rules, this prospectus does not contain all the information you can find in the registration statement or the exhibits to the registration statement. The SEC allows us to "incorporate by reference" information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, except for any information superseded by information in this prospectus. These documents contain important information about our company, our finances and our common stock. NBT BANCORP INC. SEC FILINGS (SEC FILE NO. 0-14703) We incorporate by reference the documents listed below and any future filings that we make with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, between the date of this prospectus and the termination date of this offering. o Annual Report on Form 10-K for the year ended December 31, 1999; o Quarterly Report on Form 10-Q for the quarter ended March 31, 2000; o Current Reports on Form 8-K, filed with the SEC on February 22, 2000, March 3, 2000, March 31, 2000, and April 28, 2000; and o Our SEC Rule 424(b) final prospectus, dated April 3, 2000, with respect to the section captioned "Description of NBT Capital Stock." On March 31, 2000, we filed a Current Report on Form 8-K with the SEC. The report contains our supplemental consolidated financial statements as of December 31, 1999 and 1998 and for each of the years in the three year period ended December 31, 1999, which have been restated to include the effects of the Lake Ariel Bancorp, Inc. merger, which was accounted for as a pooling of interests. We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, a copy of any or all of the information that has been incorporated by reference in the prospectus but not delivered with the prospectus. We will provide this information upon written or oral request at no cost to the requester. You may obtain documents incorporated by reference in this prospectus by requesting them in writing or by telephone from us at the following address: NBT Bancorp Inc. 52 South Broad Street Norwich, New York 13815 Attention: Michael J. Chewens, CPA Tel: (607) 337-6520 YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROSPECTUS IN MAKING YOUR DECISION TO INVEST IN OUR COMPANY AND STOCK. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM WHAT IS CONTAINED IN THIS PROSPECTUS. YOU SHOULD NOT ASSUME THAT THE INFORMATION CONTAINED IN THIS PROSPECTUS IS ACCURATE AS OF ANY DATE OTHER THAN SUCH DATE, AND THE USE OF THIS PROSPECTUS SHALL NOT CREATE ANY IMPLICATION TO THE CONTRARY. NBT BANCORP INC. We are a registered bank holding company incorporated in the State of Delaware and the parent holding company of NBT Bank, N.A. and LA Bank, N.A., each a national bank. NBT Bank is a full service commercial bank providing a broad range of financial products and services in central and northern New York. On February 17, 2000, 3

we completed our acquisition of Lake Ariel Bancorp, Inc., the parent holding company of LA Bank. Upon completion of the merger, LA Bank became our wholly-owned subsidiary. LA Bank provides commercial banking products and services in northeastern Pennsylvania. The following financial information reflects our merger with Lake Ariel on a pooled basis. In fiscal year ended December 31, 1999, our net income was $22.2 million. As of December 31, 1999, our total assets were approximately $2.0 billion, total deposits were approximately $1.5 billion and stockholders' equity was approximately $159.9 million. On December 7, 1999, we entered into an agreement with Pioneer American Holding Company Corp., a registered bank holding company incorporated in the Commonwealth of Pennsylvania. Pioneer American is the parent holding company of Pioneer American Bank, National Association, a national bank. Pioneer American Bank provides commercial banking products and services in northeastern Pennsylvania. In fiscal year 1999, Pioneer American's net income was $4.1 million. As of December 31, 1999, Pioneer American's total assets were approximately $418.8 million, total deposits were approximately $299.5 million and stockholders' equity was approximately $31.6 million. The stockholders of NBT and Pioneer American will vote upon the merger at their respective stockholders' meetings on June 20, 2000. We will account for the acquisition of Pioneer American as a pooling of interests. On April 20, 2000, we and BSB Bancorp, Inc., a Delaware corporation, announced that we would merge. Following our merger with BSB, we will be the surviving corporation. We and BSB will choose a new name for the surviving corporation before our merger with BSB occurs. The surviving corporation will have assets of approximately $4.7 billion. The surviving corporation will have three direct operating subsidiaries including two community banks (the combined NBT and BSB banks and the combined Lake Ariel and Pioneer American banks) and a financial services company, NBT Financial Services, Inc. Stockholders of BSB will receive two shares of our common stock for each share exchanged. We will issue approximately 20.5 million shares of our common stock to the former stockholders of BSB upon completion of the merger. Based on the April 19, 2000, closing price of our common stock on the Nasdaq National Market, the transaction was valued at $251 million or $24.00 per share for the outstanding common stock of BSB. The merger with BSB, which our board of directors and that of BSB have unanimously approved, is subject to approval by each company's stockholders and by banking regulators. We anticipate the merger will close in the fourth quarter of 2000. We intend the merger with BSB to be accounted for as a pooling-of-interests and to qualify as a tax-free exchange for BSB stockholders. Simultaneous with our merger with BSB, our and BSB's principal banking subsidiaries, NBT Bank and BSB Bank & Trust Company, will merge, with NBT Bank being the surviving bank in the bank merger. The surviving bank will be one of the largest independent community banks in upstate New York. The surviving bank will serve 12 counties from more than 55 offices and over 100 ATMs. A new name will be chosen for the surviving bank prior to our merger with BSB. The surviving corporation will have a 15-seat board of directors which will be made up of seven directors designated by BSB from the members of its board of directors and six directors designated by us from the members of our board, plus one designated by us from the former Lake Ariel Bancorp, Inc., which we acquired in February 2000, and who is serving on our Board and one designated by us from Pioneer American who is serving on our Board, subject to the closing of our merger with Pioneer American. If we do not complete our merger with Pioneer American before the effective time of the merger with BSB, the board of directors of the surviving corporation will consist of 13 directors, six of whom will be designated by BSB, six by us, and one former Lake Ariel board member who is serving on our Board. This former Lake Ariel board member will be designated by us. Upon completion of our merger with BSB, our common stockholders will have ownership of approximately 53 percent of the surviving corporation while BSB's common stockholders will own approximately 47 percent, assuming consummation of our merger with Pioneer American. Daryl R. Forsythe, our president and chief executive officer, will become the chairman, president and chief executive officer of the surviving corporation and William C. Craine, chairman of BSB, will become the vice chairman of the surviving corporation and chairman of its executive committee. Our Bank's president and chief operating officer, Martin A. Dietrich, will become the president and chief operating officer of the surviving bank. Michael J. 4

Chewens, our executive vice president and chief financial officer, will serve as chief financial officer for the surviving corporation. 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 surviving corporation will be located in Binghamton, New York. Other major bank functions will be conducted from the surviving corporation's Norwich, Binghamton and Scranton locations following the merger with BSB. The address of our principal executive offices is 52 South Broad Street, Norwich, New York 13815, and our telephone number is (607) 337-2265. USE OF PROCEEDS We will not receive any of the proceeds from the sale of the shares by Mr. Griffith. We will pay all expenses incurred in connection with the registration of the shares. Mr. Griffith will receive all net proceeds from the sale of the common stock under this prospectus. Mr. Griffith will pay all transaction costs associated with effecting any sales of the shares that occur. PRICE RANGE OF COMMON STOCK AND DIVIDENDS Our common stock trades on the Nasdaq National Market under the symbol "NBTB." The following table sets forth for the periods indicated (1) the range of high and low sales prices of our common stock and (2) the amount of cash dividends per share declared by us. SALES PRICES ------------ HIGH LOW DIVIDENDS ---- --- --------- 1998 First Quarter $19.05 $15.99 $ 0.117 Second Quarter 23.48 18.37 0.154 Third Quarter 23.81 17.58 0.154 Fourth Quarter 24.29 19.72 0.162 1999 First Quarter $23.33 $19.89 $ 0.162 Second Quarter 21.19 19.05 0.162 Third Quarter 20.90 16.43 0.162 Fourth Quarter 17.98 14.63 0.170 2000 First Quarter $16.50 $11.38 $0.170 Second Quarter (through ___________, 2000) xx.xx xx.xx 0.170 The timing and amount of future dividends we declare and pay will depend upon our earnings, cash requirements, and financial condition and those of our subsidiaries and, following our merger with BSB, the earnings, cash requirements, and financial condition of the surviving corporation, applicable government regulations, and other factors deemed relevant by the board of directors of the surviving corporation. Various federal and state laws limit the ability of affiliated banks to pay dividends to us. As of May 31, 2000, we had 4,814 holders of record of our common stock. 5

SELLING STOCKHOLDER The selling stockholder, David T. Griffith, offers for resale by means of this prospectus some or all of the shares that he acquired from us in May 2000 upon our acquisition of M. Griffith, Inc., a New York corporation. As a result of the acquisition, M. Griffith, Inc. became a wholly-owned subsidiary of NBT Financial Services, Inc., our wholly-owned subsidiary. Mr. Griffith was the sole stockholder of M. Griffith, Inc. In exchange for his shares of M. Griffith, Inc., we issued to Mr. Griffith and Hoover and Company as escrow agent a total of 420,989 shares of our common stock, which we refer to in this and the next section as the "subject shares." The subject shares constitute approximately 2.3% of our issued and outstanding shares as of the date of this prospectus. We have deposited a portion of the subject shares into an escrow account for the benefit of us and Mr. Griffith with Herkimer County Trust Company, Herkimer, New York, subject to an escrow agreement among us, NBT Financial Services, Inc., Mr. Griffith and Herkimer County Trust Company, dated as of May 5, 2000. In accordance with the terms of the escrow agreement, the escrow agent may release from escrow a portion of the escrowed shares to Mr. Griffith over the term of the escrow agreement only upon fulfillment of certain express employment conditions by Mr. Griffith. If and when such escrowed shares are released to Mr. Griffith from escrow, Mr. Griffith may sell any or all of such former escrowed shares. We will maintain the registered status of the escrowed shares with the SEC, thereby permitting Mr. Griffith to sell any of the subject shares upon their release from escrow. We will receive no portion of any proceeds from any sale of any of the subject shares by Mr. Griffith. Prior to our acquisition of M. Griffith, Inc., Mr. Griffith had no relationship or affiliation with us or any of our affiliates. Following the acquisition, Mr. Griffith entered into a three-year employment agreement with us as president of our subsidiary, M. Griffith, Inc. We are registering Mr. Griffith's shares to permit public secondary trading of the subject shares by Mr. Griffith and to allow Mr. Griffith to offer the subject shares for resale at such times as he chooses. We cannot give any estimate as to the number of shares that Mr. Griffith will hold after completion of this offering because he may offer some or all of the subject shares and because there currently are no agreements, arrangements or understandings with respect to the sale of any of the subject shares. Mr. Griffith may offer from time to time the subject shares held directly by him and those currently held in escrow but released from escrow to Mr. Griffith in the future. PLAN OF DISTRIBUTION We are registering all of the 420,989 subject shares of our common stock on behalf of Mr. Griffith. We issued the subject shares to Mr. Griffith and to the escrow agent in connection with our acquisition of M. Griffith, Inc. under an exemption from the registration requirements of the Securities Act of 1933, provided by Section 4(2) of that statute. We are registering the shares in accordance with the provisions of our acquisition agreement with M. Griffith, Inc. Depending on market conditions and other factors, Mr. Griffith may sell some or all of the subject shares offered by this prospectus from time to time, in one or more transactions, on the Nasdaq National Market, or otherwise, at market prices prevailing at the time of sale, at negotiated prices, or at fixed prices, which may be changed. Mr. Griffith may effect such sales directly, or through agents, or through dealers. Mr. Griffith may sell some or all of the subject shares in ordinary broker's transactions or through privately negotiated transactions or through a combination of any of these methods of sale. In connection with his sales, Mr. Griffith may pay usual and customary or specifically negotiated brokerage fees or commissions. Mr. Griffith will act independently from us in making decisions with respect to the timing, manner and size of each sale. The aggregate proceeds to Mr. Griffith from the sale of the subject shares will be the purchase price of the common stock sold less the aggregate agents' commissions, if any, and other expenses of issuance and distribution not borne by us. Mr. Griffith and any dealers or agents that participate in the distribution of the subject shares may be deemed to be "underwriters" within the meaning of the Securities Act of 1933. Any profit on the sale of the shares and any commissions received by any such dealer or agent in effecting sales of Mr. Griffith's shares may be deemed to be underwriting discounts and commissions under the Securities Act. There is no underwriter or coordinating broker acting in connection with the proposed sale of the subject shares by Mr. Griffith. 6

Mr. Griffith will sell the subject shares only through registered or licensed brokers or dealers if required under applicable state securities laws. Because Mr. Griffith may be deemed to be an underwriter within the meaning of Section 2(11) under the Securities Act, he will be subject to the prospectus delivery requirements of the Securities Act. We will make copies of this prospectus available to Mr. Griffith and have informed him of the need for delivery of copies of this prospectus to purchasers at or prior to the time of any sale of the subject shares. We will bear all costs and expenses, including registration and accounting fees and the fees, disbursements and expenses of our counsel, in connection with the registration of the subject shares under the Securities Act. Mr. Griffith will bear all commissions and discounts, if any, payable with respect to sales of the subject shares. Mr. Griffith will pay any transaction costs associated with effecting any sales that occur. Mr. Griffith may agree to indemnify any broker-dealer or agent that participates in transactions involving sales of the subject shares against certain liabilities, including liabilities arising under the Securities Act. DESCRIPTION OF NBT CAPITAL STOCK AUTHORIZED CAPITAL STOCK. Our current authorized stock consists of 30,000,000 shares of common stock, $.01 par value per share, and 2,500,000 shares of preferred stock, $.01 par value per share. No shares of the preferred stock are outstanding. Our Board is authorized to issue, without further stockholder approval, preferred stock from time to time in one or more series, and to determine the provisions applicable to each series, including the number of shares, dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption, sinking fund provisions, redemption price or prices, and liquidation preferences. As of May 31, 2000, 18,522,291 shares of our common stock were outstanding. Additionally, upon completion of our mergers with Pioneer American and BSB, we anticipate issuing approximately 5.2 million shares and 20.5 million shares, respectively, to the former stockholders of those corporations. Prior to completion of our merger with BSB, we will request our stockholders to amend our Certificate of Incorporation to increase the number of our authorized shares of common stock so that we will have a sufficient number of authorized shares to issue in our merger with BSB. COMMON STOCK. Under Delaware law, stockholders generally are not personally liable for a corporation's acts or debts. Subject to the preferential rights of any other shares or series of capital stock, holders of shares of our common stock are entitled to receive dividends on shares of common stock if, as and when authorized and declared by our Board out of funds legally available for dividends and to share ratably in our assets legally available for distribution to our stockholders in the event of our liquidation, dissolution or winding-up after payment of, or adequate provision for, all of our known debts and liabilities. Each outstanding share of our common stock entitles the holder to one vote on all matters submitted to a vote of stockholders, including the election of directors. Unless a larger vote is required by law, our certificate of incorporation or our bylaws, when a quorum is present at a meeting of stockholders, a majority of the votes properly cast upon any question other than the election of directors shall decide the question. A plurality of the votes properly cast for the election of a person to serve as a director shall elect such person. Except as otherwise required by law or except as provided with respect to any other class or series of capital stock, the holders of our common stock possess the exclusive voting power. There is no cumulative voting in the election of directors. Our Board is classified into three categories with each category equal in number. This means, in general, that one-third of the members of our Board are subject to reelection at each annual meeting of stockholders. Holders of our common stock have no conversion, sinking fund or redemption rights, or preemptive rights to subscribe for any of our classes of stock. All shares of our common stock have equal dividend, distribution, liquidation and other rights, and have no preference, appraisal or exchange rights. PREFERRED STOCK. Our Board is authorized, without any further vote or action by our stockholders, to issue shares of preferred stock in one or more series, to establish the number of shares in each series and to fix the designation, 7

powers, preferences and rights of each such series and the qualifications, limitations or restrictions of the series, in each case, if any, as are permitted by Delaware law. Because our Board has the power to establish the preferences and rights of each class or series of preferred stock, it may afford the stockholders of any series or class of preferred stock preferences, powers and rights, voting or otherwise, senior to the rights of holders of shares of our common stock. The issuance of shares of preferred stock could have the effect of delaying, deferring or preventing a change in control of our corporation. STOCKHOLDER RIGHTS PLAN. In November 1994, we adopted a stockholder rights plan designed to ensure that any potential acquiror of our corporation would negotiate with our Board and that all of our stockholders would be treated equitably in the event of a takeover attempt. At that time, we paid a dividend of one Preferred Share Purchase Right for each outstanding share of our common stock. Similar rights are attached to each share of our common stock issued after November 15, 1994. Under the rights plan, the rights will not be exercisable until a person or group acquires beneficial ownership of 20 percent or more of our outstanding common stock, begins a tender or exchange offer for 25 percent or more of our common stock, or an adverse person, as declared by our Board, acquires 10 percent or more of our common stock. Additionally, until the occurrence of such an event, the rights are not severable from our common stock and therefore, the rights will transfer upon the transfer of shares of our common stock. Upon the occurrence of such events, each right entitles the holder to purchase one one-hundredth of a share of our Series R Preferred Stock, $.01 par value per share, at a price of $100. The rights plan also provides that upon the occurrence of certain specified events the holders of rights will be entitled to acquire additional equity interests in us or in the acquiring entity, such interests having a market value of two times the right's exercise price of $100. The rights expire November 14, 2004, and are redeemable in whole, but not in part, at our option prior to the time they become exercisable, for a price of $.01 per right. The rights have certain anti-takeover effects. The rights may cause substantial dilution to a person or group that attempts to acquire us on terms not approved by our Board. The rights should not interfere with any merger or other business combination approved by our Board. REGISTRAR AND TRANSFER AGENT. Our registrar and transfer agent is American Stock Transfer and Trust Company, New York, New York. LEGAL MATTERS The validity of the shares of our common stock offered hereby has been passed upon by Duane, Morris & Heckscher LLP, Washington, D.C. EXPERTS The consolidated financial statements and the supplemental consolidated financial statements of NBT as of December 31, 1999 and 1998 and for each of the years in the three-year period ended December 31, 1999 have been incorporated by reference in this prospectus and registration statement in reliance upon the reports of KPMG LLP, independent certified public accountants, which are incorporated herein by reference, and upon the authority of said firm as experts in accounting and auditing. The consolidated financial statements of Pioneer American as of December 31, 1999 and 1998 and for each of the years in the three-year period ended December 31, 1999, have been incorporated by reference in this prospectus and registration statement in reliance upon the report of KPMG LLP, independent certified public accountants, which is incorporated herein by reference, and upon the authority of said firm as experts in accounting and auditing. The consolidated financial statements of BSB Bancorp, Inc. as of December 31, 1999 and 1998 and for each of the years in the three-year period ended December 31, 1999 have been incorporated by reference in this prospectus and registration statement in reliance upon the report of PricewaterhouseCoopers LLP, independent certified public accountants, given on the authority of said firm as experts in accounting and auditing. 8

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS We have used and incorporated by reference "forward-looking statements" in this prospectus. Words such as "will," "will permit," "will afford," "believes," "expects," "may," "should," "projected," "contemplates," or "anticipates" may constitute forward-looking statements. These statements are within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and are subject to risks and uncertainties that could cause our actual results to differ materially. We have used these statements to describe our expectations and estimates in various sections of this prospectus, including: o NBT Bancorp Inc.; o Selling Stockholder; o Plan of Distribution; and o Description of NBT Capital Stock. Factors that might cause such differences include, but are not limited to: the timing of closing of our proposed mergers being delayed; competitive pressures among financial institutions increasing significantly; economic conditions, either nationally or locally in areas in which we and our prospective merger partners conduct our respective operations, being less favorable than expected; the cost and effort required to integrate aspects of the operations of the companies we will acquire being more difficult than we expected; our expected cost savings from our proposed mergers not being fully realized or realized within the expected time frame; legislation or regulatory changes which adversely affect the ability of our company following our proposed acquisitions to conduct its current and future operations; and the impact of the transition to the year 2000 on the operations of us or our merger partners. We disclaim any obligation to update any such factors or to publicly announce the result of any revisions to any of the forward-looking statements included in this prospectus to reflect future events or developments. Our actual results could differ materially from those set forth in the forward-looking statements because of many reasons, including the risk factors we list above. This list may not be exhaustive. 9

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS The following unaudited pro forma condensed combined balance sheet presents the financial position of NBT Bancorp Inc. (NBT), BSB Bancorp, Inc. (BSB), and Pioneer American Holding Company Corp. (Pioneer American) as of March 31, 2000 assuming that both mergers had occurred as of March 31, 2000 after giving effect to certain pro forma adjustments described in the accompanying notes. The following unaudited pro forma condensed combined statements of income for the three months ended March 31, 2000 and 1999, and the years ended December 31, 1999, 1998, and 1997 present the combined historical results of operations of NBT, BSB, and Pioneer American as if the mergers had been completed as of the first day of the period presented. The historical financial information of NBT has been restated to include the effects of the merger with Lake Ariel Bancop, Inc. (Lake Ariel), which was completed on February 17, 2000 and has been accounted for as a pooling of interests. Pro forma earnings per share are based on the exchange ratios of 2.0 and 1.805 for the BSB and Pioneer American mergers, respectively. The fiscal years of NBT, BSB, and Pioneer American end December 31. The unaudited pro forma condensed combined balance sheet reflects estimated non-recurring charges that may be incurred in connection with the mergers. The unaudited pro forma condensed combined financial statements were prepared giving effect to the mergers on the pooling of interests accounting method. Under this method of accounting, the recorded assets, liabilities, stockholders' equity, income and expense of NBT, BSB, and Pioneer American are combined and reflected at their historical amounts, except as noted in the accompanying notes. The combined company expects to achieve certain merger benefits in the form of operating expense reductions and revenue enhancements. The unaudited pro forma condensed combined statements of income do not reflect potential operating expense reductions or revenue enhancements that are expected to result from the mergers, and therefore may not be indicative of the results of future operations. No assurance can be given with respect to the ultimate level of operating expense reductions or revenue enhancements. The unaudited pro forma condensed combined financial statements should be read in conjunction with, and are qualified in their entirety by, the historical consolidated financial statements and accompanying notes of NBT, BSB, and Pioneer American and the supplemental consolidated financial statements and accompanying notes of NBT, which have been restated to include the effects of the Lake Ariel merger. These supplemental financial statements were included in Current Report on Form 8-K, dated March 31, 2000 and incorporated by reference herein. The following historical financial information of Pioneer American and BSB has been derived from the respective companies' interim consolidated financial statements as of March 31, 2000 and for the three months ended March 31, 2000 and 1999 which are included in the respective companies Form 10-Q for the three months ended March 31, 2000 and filed with the SEC, and their respective consolidated financial statements and accompanying notes as of December 31, 1999 and 1998 and for each of the years in the three year period ended December 31, 1999, which were included in the respective companies' Form 10-K for the year ended December 31, 1999. The consolidated financial statements of BSB and Pioneer American as of December 31, 1999 and 1998 and for each of the years in the three year period ended December 31, 1999 are incorporated by reference into this registration statement. The unaudited pro forma condensed combined financial statements are presented for informational purposes only. These statements are not necessarily indicative of the combined financial position and results of operations that would have occurred if the mergers had been completed on March 31, 2000 or at the beginning of the respective periods presented or that may be attained in the future. 10

Unaudited Pro Forma Condensed Combined Balance Sheet March 31, 2000 (in thousands) NBT BSB Pioneer American NBT BSB Pro Forma Combined Holding Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Company Corp. Adjustments Pro Forma ------------ ------------- ----------- --------- ---------------- ----------- --------- ASSETS Cash and cash equivalents $ 60,823 $ 47,718 $ -- $ 108,541 $ 13,216 $ -- $ 121,757 Securities available for sale, at fair value 497,528 382,703 -- 880,231 105,239 -- 985,470 Securities held to maturity (fair value-NBT Bancorp Inc. $75,808, BSB Bancorp, Inc. $13,208, and Pioneer American Holding Company Corp. $34,560) 78,772 13,079 -- 91,851 35,746 -- 127,597 Loans 1,295,651 1,745,959 3,041,610 245,147 3,286,757 Less: Allowance for loan losses 17,543 31,705 -- 49,248 3,145 -- 52,393 - ----------------------------------------------------------------------------------------------------------------------------------- Net loans 1,278,108 1,714,254 -- 2,992,362 242,002 -- 3,234,364 Premises and equipment, net 40,292 15,541 -- 55,833 5,910 -- 61,743 Other assets 73,583 57,569 4,500 135,652 13,615 1,300 150,567 - ----------------------------------------------------------------------------------------------------------------------------------- TOTAL ASSETS $ 2,029,106 $ 2,230,864 $ 4,500 $4,264,470 $ 415,728 $ 1,300 $4,681,498 =================================================================================================================================== LIABILITIES AND STOCKHOLDERS' EQUITY Deposits: Demand (noninterest bearing) $ 210,579 $ 139,639 $ -- $ 350,218 $ 45,842 $ -- 396,060 Savings,NOW, and money market 490,328 653,091 -- 1,143,419 110,880 -- 1,254,299 Time 822,842 1,106,548 -- 1,929,390 143,152 -- 2,072,542 - ----------------------------------------------------------------------------------------------------------------------------------- Total deposits 1,523,749 1,899,278 -- 3,423,027 299,874 -- 3,722,901 Borrowings 327,238 135,982 -- 463,220 79,489 -- 542,709 Other liabilities 15,587 8,588 16,500 40,675 4,272 5,100 50,047 Mandatorily redeemable preferred securities of subsidiary -- 30,000 -- 30,000 -- -- 30,000 - ----------------------------------------------------------------------------------------------------------------------------------- Total liabilities 1,866,574 2,073,848 16,500 3,956,922 383,635 5,100 4,345,657 - ----------------------------------------------------------------------------------------------------------------------------------- Stockholders' equity: Preferred stock -- -- -- -- -- -- -- Common stock 186 114 91 391 2,935 (2,883) 443 Additional paid-in-capital 167,047 37,590 (13,548) 191,089 11,962 1,153 204,204 Retained earnings 24,225 143,481 (12,000) 155,706 22,355 (3,800) 174,261 Accumulated other comprehensive income (loss) (17,615) (10,712) -- (28,327) (3,429) -- (31,756) Common stock in treasury, at cost (11,311) (13,457) 13,457 (11,311) (1,730) 1,730 (11,311) - ----------------------------------------------------------------------------------------------------------------------------------- Total stockholders' equity 162,532 157,016 (12,000) 307,548 32,093 (3,800) 335,841 - ----------------------------------------------------------------------------------------------------------------------------------- TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY $ 2,029,106 $ 2,230,864 $ 4,500 $4,264,470 $ 415,728 $ 1,300 $4,681,498 =================================================================================================================================== See accompanying notes to unaudited pro forma condensed combined financial statements 11

Unaudited Pro Forma Condensed Combined Statement of Income For the Three Months Ended March 31, 2000 Pioneer NBT NBT American BSB BSB Holding Pioneer NBT BSB Pro Forma Combined Company Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Corp. Adjustments Pro Forma ------------ ------------- ----------- --------- ----------- ----------- ---------- Interest and fee income: Loan $ 27,189 $ 39,593 $ -- $ 66,782 $ 5,048 $ -- $ 71,830 Securities 9,865 6,674 -- 16,539 2,358 -- 18,897 Other 402 13 -- 415 4 -- 419 - -------------------------------------------------------------------------------------------------------------------------------- Total interest and fee income: 37,456 46,280 -- 83,736 7,410 -- 91,146 - -------------------------------------------------------------------------------------------------------------------------------- Interest expense: Deposits 13,446 21,319 -- 34,765 2,637 -- 37,402 Borrowings 4,400 2,582 -- 6,982 1,135 -- 8,117 - -------------------------------------------------------------------------------------------------------------------------------- Total interest expense 17,846 23,901 -- 41,747 3,772 -- 45,519 - -------------------------------------------------------------------------------------------------------------------------------- Net interest income 19,610 22,379 -- 41,989 3,638 -- 45,627 Provision for loan losses 1,334 4,608 -- 5,942 120 -- 6,062 - -------------------------------------------------------------------------------------------------------------------------------- Net interest income after provision for loan losses 18,276 17,771 -- 36,047 3,518 -- 39,565 - -------------------------------------------------------------------------------------------------------------------------------- Noninterest income: Trust 860 331 -- 1,191 -- -- 1,191 Service charges on deposit accounts 1,620 1,213 -- 2,833 526 -- 3,359 Net security gains (losses) - - -- -- -- -- -- Other 1,135 1,817 -- 2,952 195 -- 3,147 - -------------------------------------------------------------------------------------------------------------------------------- Total noninterest income 3,615 3,361 -- 6,976 721 -- 7,697 - -------------------------------------------------------------------------------------------------------------------------------- Noninterest expense: Salaries and employee benefits 7,081 5,899 -- 12,980 1,322 -- 14,302 Office supplies and postage 592 393 -- 985 119 -- 1,104 Occupancy 1,232 727 -- 1,959 269 -- 2,228 Equipment 1,137 442 -- 1,579 225 -- 1,804 Professional fees and outside services 756 1,479 -- 2,235 240 -- 2,475 Data processing and communications 1,132 416 -- 1,548 96 -- 1,644 Amortization of intangible assets 312 96 -- 408 10 -- 418 Merger and acquisition charges 1,122 -- -- 1,122 -- -- 1,122 Other operating 1,619 2,261 -- 3,880 494 -- 4,374 - -------------------------------------------------------------------------------------------------------------------------------- Total noninterest expense 14,983 11,713 -- 26,696 2,775 -- 29,471 - -------------------------------------------------------------------------------------------------------------------------------- Income before income taxes 6,908 9,419 -- 16,327 1,464 -- 17,791 Income taxes 2,667 3,671 -- 6,338 425 -- 6,763 - -------------------------------------------------------------------------------------------------------------------------------- - -------------------------------------------------------------------------------------------------------------------------------- Net Income $ 4,241 $ 5,748 $ -- $ 9,989 $ 1,039 $ -- $ 11,028 ================================================================================================================================ Weighted Average Shares Outstanding Basic 18,028 10,243 38,514 2,864 43,684 Diluted 18,134 10,337 38,808 2,887 44,019 Earnings Per Share Basic 0.24 0.56 0.26 0.36 0.25 Diluted 0.23 0.56 0.26 0.36 0.25 See accompanying notes to unaudited pro forma condensed combined financial statements 12

Unaudited Pro Forma Condensed Combined Statement of Income For the Three Months Ended March 31, 1999 Pioneer NBT NBT American BSB BSB Holding Pioneer NBT BSB Pro Forma Combined Company Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Corp. Adjustments Pro Forma ------------ -------------- ------------ ---------- --------- ------------ ---------- Interest and fee income: Loan $ 22,679 $ 35,463 $ -- $ 58,142 $ 4,812 $ -- $ 62,954 Securities 8,465 6,838 -- 15,303 2,291 -- 17,594 Other 458 204 -- 662 82 -- 744 - ---------------------------------------------------------------------------------------------------------------------------------- Total interest and fee income: 31,602 42,505 -- 74,107 7,185 -- 81,292 - ---------------------------------------------------------------------------------------------------------------------------------- Interest expense: Deposits 11,006 17,927 -- 28,933 2,729 -- 31,662 Borrowings 2,878 3,466 -- 6,344 968 -- 7,312 - ---------------------------------------------------------------------------------------------------------------------------------- Total interest expense 13,884 21,393 -- 35,277 3,697 -- 38,974 - ---------------------------------------------------------------------------------------------------------------------------------- Net interest income 17,718 21,112 -- 38,830 3,488 -- 42,318 Provision for loan losses 1,120 3,461 -- 4,581 75 -- 4,656 - ---------------------------------------------------------------------------------------------------------------------------------- Net interest income after provision for loan losses 16,598 17,651 -- 34,249 3,413 -- 37,662 - ---------------------------------------------------------------------------------------------------------------------------------- Noninterest income: Trust 835 251 -- 1,086 -- -- 1,086 Service charges on deposit accounts 1,408 1,000 -- 2,408 517 -- 2,925 Net security gains (losses) 668 (401) -- 267 -- -- 267 Other 1,365 1,539 -- 2,904 126 -- 3,030 - ---------------------------------------------------------------------------------------------------------------------------------- Total noninterest income 4,276 2,389 -- 6,665 643 -- 7,308 - ---------------------------------------------------------------------------------------------------------------------------------- Noninterest expense: Salaries and employee benefits 5,970 5,081 -- 11,051 1,331 -- 12,382 Office supplies and postage 637 433 -- 1,070 145 -- 1,215 Occupancy 1,024 773 -- 1,797 285 -- 2,082 Equipment 947 427 -- 1,374 242 -- 1,616 Professional fees and outside services 697 1,331 -- 2,028 183 -- 2,211 Data processing and communications 972 490 -- 1,462 118 -- 1,580 Amortization of intangible assets 329 96 -- 425 10 -- 435 Other operating 1,240 2,533 -- 3,773 559 -- 4,332 - ---------------------------------------------------------------------------------------------------------------------------------- Total noninterest expense 11,816 11,164 -- 22,980 2,873 -- 25,853 - ---------------------------------------------------------------------------------------------------------------------------------- Income before income taxes 9,058 8,876 -- 17,934 1,183 -- 19,117 Income taxes 3,282 3,340 -- 6,622 300 -- 6,922 - ---------------------------------------------------------------------------------------------------------------------------------- - ---------------------------------------------------------------------------------------------------------------------------------- Net Income $ 5,776 $ 5,536 $ -- $ 11,312 $ 883 $ -- $ 12,195 ================================================================================================================================== Weighted Average Shares Outstanding Basic 17,860 10,071 38,002 2,921 43,274 Diluted 18,104 10,341 38,786 2,947 44,105 Earnings Per Share Basic 0.32 0.55 0.30 0.30 0.28 Diluted 0.32 0.54 0.29 0.30 0.28 See accompanying notes to unaudited pro forma condensed combined financial statements 13

Unaudited Pro Forma Condensed Combined Statement of Income For the Year Ended December 31, 1999 Pioneer NBT NBT American BSB BSB Holding Pioneer NBT BSB Pro Forma Combined Company Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Corp. Adjustments Pro Forma ------------ ------------- ----------- --------- ---------- ------------ ----------- Interest and fee income: Loans $ 96,235 $ 151,001 $ -- $ 247,236 $ 19,661 $ -- $ 266,897 Securities 38,166 25,038 -- 63,204 9,491 -- 72,695 Other 988 682 -- 1,670 237 -- 1,907 - -------------------------------------------------------------------------------------------------------------------------------- Total interest and fee income: 135,389 176,721 -- 312,110 29,389 -- 341,499 - -------------------------------------------------------------------------------------------------------------------------------- Interest expense: Deposits 46,067 75,542 -- 121,609 10,519 -- 132,128 Borrowings 14,515 14,034 -- 28,549 4,379 -- 32,928 - -------------------------------------------------------------------------------------------------------------------------------- Total interest expense 60,582 89,576 -- 150,158 14,898 -- 165,056 - -------------------------------------------------------------------------------------------------------------------------------- Net interest income 74,807 87,145 -- 161,952 14,491 -- 176,443 Provision for loan losses 5,070 19,137 -- 24,207 370 -- 24,577 - -------------------------------------------------------------------------------------------------------------------------------- Net interest income after provision for loan losses 69,737 68,008 -- 137,745 14,121 -- 151,866 - -------------------------------------------------------------------------------------------------------------------------------- Noninterest income: Trust 3,305 1,104 -- 4,409 -- -- 4,409 Service charges on deposit accounts 6,303 4,382 -- 10,685 1,635 -- 12,320 Net security gains (losses) 1,716 (231) -- 1,485 88 -- 1,573 Other 5,097 7,116 -- 12,213 1,108 -- 13,321 - -------------------------------------------------------------------------------------------------------------------------------- Total noninterest income 16,421 12,371 -- 28,792 2,831 -- 31,623 - -------------------------------------------------------------------------------------------------------------------------------- Noninterest expense: Salaries and employee benefits 25,213 20,386 -- 45,599 5,291 -- 50,890 Office supplies and postage 2,436 1,684 -- 4,120 534 -- 4,654 Occupancy 4,317 2,874 -- 7,191 1,062 -- 8,253 Equipment 4,230 1,733 -- 5,963 990 -- 6,953 Professional fees and outside services 3,325 6,001 -- 9,326 1,005 -- 10,331 Data processing and communications 4,091 1,930 -- 6,021 437 -- 6,458 Amortization of intangible assets 1,278 386 -- 1,664 39 -- 1,703 Merger and acquisition charges 798 5,408 -- 6,206 -- -- 6,206 Other operating 5,812 10,261 -- 16,073 2,024 -- 18,097 - -------------------------------------------------------------------------------------------------------------------------------- Total noninterest expense 51,500 50,663 -- 102,163 11,382 -- 113,545 - -------------------------------------------------------------------------------------------------------------------------------- Income before income taxes 34,658 29,716 -- 64,374 5,570 -- 69,944 Income taxes 12,483 11,491 -- 23,974 1,488 -- 25,462 - -------------------------------------------------------------------------------------------------------------------------------- - -------------------------------------------------------------------------------------------------------------------------------- Net Income $ 22,175 $ 18,225 $ -- $ 40,400 $ 4,082 $ -- $ 44,482 ================================================================================================================================ Weighted Average Shares Outstanding Basic 17,851 10,138 38,127 2,902 43,365 Diluted 18,095 10,312 38,719 2,929 44,006 Earnings Per Share Basic 1.24 1.80 1.06 1.41 1.03 Diluted 1.23 1.77 1.04 1.39 1.01 See accompanying notes to unaudited pro forma condensed combined financial statements 14

Unaudited Pro Forma Condensed Combined Statement of Income For the Year Ended December 31, 1998 Pioneer NBT NBT American BSB BSB Holding Pioneer NBT BSB Pro Forma Combined Company Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Corp. Adjustments Pro Forma ------------- ------------- ------------ ----------- ---------- ------------- ---------- Interest and fee income: Loans $ 89,399 $ 139,374 $ -- $ 228,773 $ 19,093 $ -- $ 247,866 Securities 40,370 25,926 -- 66,296 8,729 -- 75,025 Other 531 866 -- 1,397 480 -- 1,877 - ----------------------------------------------------------------------------------------------------------------------------------- Total interest and fee income: 130,300 166,166 -- 296,466 28,302 -- 324,768 - ----------------------------------------------------------------------------------------------------------------------------------- Interest expense: Deposits 48,058 72,387 -- 120,445 10,840 -- 131,285 Borrowings 12,359 12,399 -- 24,758 3,479 -- 28,237 - ----------------------------------------------------------------------------------------------------------------------------------- Total interest expense 60,417 84,786 -- 145,203 14,319 -- 159,522 - ----------------------------------------------------------------------------------------------------------------------------------- Net interest income 69,883 81,380 -- 151,263 13,983 -- 165,246 Provision for loan losses 5,729 12,931 -- 18,660 420 -- 19,080 - ---------------------------------------------------------------------------------------------------------------------------------- Net interest income after provision for loan losses 64,154 68,449 -- 132,603 13,563 -- 146,166 - ----------------------------------------------------------------------------------------------------------------------------------- Noninterest income: Trust 3,115 994 -- 4,109 -- -- 4,109 Service charges on deposit accounts 5,325 3,714 -- 9,039 1,404 -- 10,443 Net security gains (losses) 1,056 (851) -- 205 511 -- 716 Other 5,417 4,738 -- 10,155 1,046 -- 11,201 - ----------------------------------------------------------------------------------------------------------------------------------- Total noninterest income 14,913 8,595 -- 23,508 2,961 -- 26,469 - ----------------------------------------------------------------------------------------------------------------------------------- Noninterest expense: Salaries and employee benefits 24,215 19,528 -- 43,743 5,071 -- 48,814 Office supplies and postage 2,523 1,998 -- 4,521 506 -- 5,027 Occupancy 4,132 2,911 -- 7,043 1,027 -- 8,070 Equipment 3,599 1,466 -- 5,065 773 -- 5,838 Professional fees and outside services 3,375 4,086 -- 7,461 1,027 -- 8,488 Data processing and communications 3,796 2,027 -- 5,823 483 -- 6,306 Amortization of intangible assets 1,275 386 -- 1,661 39 -- 1,700 Other operating 7,665 9,581 -- 17,246 2,041 -- 19,287 - ----------------------------------------------------------------------------------------------------------------------------------- Total noninterest expense 50,580 41,983 -- 92,563 10,967 -- 103,530 - ----------------------------------------------------------------------------------------------------------------------------------- Income before income taxes 28,487 35,061 -- 63,548 5,557 -- 69,105 Income taxes 5,614 13,542 -- 19,156 1,535 -- 20,691 - ----------------------------------------------------------------------------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------------- Net Income $ 22,873 $ 21,519 $ -- $ 44,392 $ 4,022 $ -- $ 48,414 =================================================================================================================================== Weighted Average Shares Outstanding Basic 17,976 10,006 37,988 2,894 43,212 Diluted 18,361 10,365 39,091 2,953 44,421 Earnings Per Share Basic 1.27 2.15 1.17 1.39 1.12 Diluted 1.25 2.08 1.14 1.36 1.09 See accompanying notes to unaudited pro forma condensed combined financial statements 15

Unaudited Pro Forma Condensed Combined Statement of Income For the Year Ended December 31, 1997 NBT NBT Pioneer BSB BSB American Pioneer NBT BSB Pro Forma Combined Holding Pro Forma Combined Bancorp Inc. Bancorp, Inc. Adjustments Pro Forma Company Corp. Adjustments Pro Forma ------------ ------------- ----------- ----------- ------------- ------------ ----------- Interest and fee income: Loans $ 81,688 $ 120,750 $ -- $ 202,438 $ 18,101 $ -- $ 220,539 Securities 38,536 20,398 -- 58,934 8,086 -- 67,020 Other 607 200 -- 807 320 -- 1,127 - ---------------------------------------------------------------------------------------------------------------------------------- Total interest and fee income: 120,831 141,348 -- 262,179 26,507 -- 288,686 - ---------------------------------------------------------------------------------------------------------------------------------- Interest expense: Deposits 45,629 60,180 -- 105,809 11,337 -- 117,146 Borrowings 10,418 11,272 -- 21,690 1,508 -- 23,198 - ---------------------------------------------------------------------------------------------------------------------------------- Total interest expense 56,047 71,452 -- 127,499 12,845 -- 140,344 - ---------------------------------------------------------------------------------------------------------------------------------- Net interest income 64,784 69,896 -- 134,680 13,662 -- 148,342 Provision for loan losses 4,285 10,814 -- 15,099 535 -- 15,634 - ---------------------------------------------------------------------------------------------------------------------------------- Net interest income after provision for loan losses 60,499 59,082 -- 119,581 13,127 -- 132,708 - ---------------------------------------------------------------------------------------------------------------------------------- Noninterest income: Trust 2,675 709 -- 3,384 -- -- 3,384 Service charges on deposit accounts 4,942 3,297 -- 8,239 1,397 -- 9,636 Net security gains (losses) (123) 380 -- 257 157 -- 414 Other 3,973 3,762 -- 7,735 907 -- 8,642 - ---------------------------------------------------------------------------------------------------------------------------------- Total noninterest income 11,467 8,148 -- 19,615 2,461 -- 22,076 - ---------------------------------------------------------------------------------------------------------------------------------- Noninterest expense: Salaries and employee benefits 22,111 17,121 -- 39,232 5,040 -- 44,272 Office supplies and postage 2,250 1,886 -- 4,136 507 -- 4,643 Occupancy 3,754 2,547 -- 6,301 1,026 -- 7,327 Equipment 2,632 1,378 -- 4,010 685 -- 4,695 Professional fees and outside services 2,485 2,716 -- 5,201 900 -- 6,101 Data processing and communications 2,966 1,358 -- 4,324 456 -- 4,780 Amortization of intangible assets 1,505 386 -- 1,891 39 -- 1,930 Other operating 6,677 9,548 -- 16,225 1,427 -- 17,652 - ---------------------------------------------------------------------------------------------------------------------------------- Total noninterest expense 44,380 36,940 -- 81,320 10,080 -- 91,400 - ---------------------------------------------------------------------------------------------------------------------------------- Income before income taxes 27,586 30,290 -- 57,876 5,508 -- 63,384 Income taxes 9,406 11,641 -- 21,047 1,500 -- 22,547 - ---------------------------------------------------------------------------------------------------------------------------------- - ---------------------------------------------------------------------------------------------------------------------------------- Net Income $ 18,180 $ 18,649 $ -- $ 36,829 $ 4,008 $ -- $ 40,837 ================================================================================================================================== Weighted Average Shares Outstanding Basic 17,095 9,905 36,905 2,850 42,049 Diluted 17,393 10,258 37,909 2,939 43,214 Earnings Per Share Basic 1.06 1.88 1.00 1.41 0.97 Diluted 1.05 1.82 0.97 1.36 0.94 See accompanying notes to unaudited pro forma condensed combined financial statements 16

NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS (1) Pro forma earnings per share have been calculated on the applicable weighted average number of shares of NBT plus the additional shares of NBT assumed to be issued in the mergers in exchange for the weighted average outstanding shares of BSB and Pioneer American for each applicable period based on the exchange ratios of 2.0 and 1.805, respectively. (2) Pro forma entry to retire treasury stock held by BSB (approximately 1,174,216 shares having a par value of $.01 per share): Common Stock ........................................................ 11,742 Paid in Capital ..................................................... 13,445,258 Treasury Stock .................................................. 13,457,000 BSB common stock issued at March 31, 2000 ........................... 11,430,761 Less treasury stock retired above ................................... (1,174,216) ---------- BSB common stock issued and outstanding at March 31, 2000........... 10,256,545 ========== Pro forma entry to issue 2.0 shares of NBT common stock in exchange for each share of BSB common stock: NBT common stock issued at March 31, 2000 .................................. 18,623,435 NBT common stock issued in exchange for BSB common stock after retirement of BSB's treasury stock (10,256,545 shares of BSB common stock times conversion ratio of 2.0).................................................... 20,513,090 ---------- Combined NBT/BSB pro forma total shares of common stock issued ............. 39,136,525 Par value per share of NBT common stock .................................... $.01 ----------- Combined NBT/BSB pro forma total par value ................................. $391,365 =========== Actual par value of common stock at March 31, 2000: NBT ........................................................................ $186,234 BSB (after retirement of treasury shares) .................................. 102,566 ----------- Total ...................................................................... $288,800 =========== Required increase in par value ............................................. $102,565 =========== Entry to conform par value of common stock: Paid in Capital....................................................... 102,565 Common stock...................................................... 102,565 17

Summary of pro forma entries above: Paid in Capital........................................................ 13,547,823 Common Stock....................................................... 90,823 Treasury Stock..................................................... 13,457,000 (3) Pro forma entry to retire treasury stock held by Pioneer American (approximately 71,060 shares having a par value of $1.00 per share): Common Stock....................................................... 71,060 Paid in Capital.................................................... 1,658,739 Treasury Stock................................................. 1,729,799 Pro forma entry to issue 1.805 shares of NBT common stock in exchange for each share of Pioneer American common stock. The par value of NBT common stock to be issued is determined as follows: Combined NBT/BSB pro forma common stock issued at March 31, 2000 (note 1)................................................................. 39,136,525 NBT common stock issued in exchange for Pioneer American common stock after retirement of Pioneer American treasury stock (2,864,307 shares of Pioneer American common stock times conversion ratio of 1.805).. 5,170,074 ----------- Combined pro forma total shares of common stock issued............. 44,306,599 Par value per share of common stock................................ $.01 ----------- Combined pro forma total par value................................. $ 443,066 =========== Actual par value of common stock at March 31, 2000: NBT/BSB combined pro forma (note 1)................................ $ 391,365 Pioneer American (after retirement of treasury shares)............. 2,864,307 --------- Total.............................................................. $ 3,255,672 ========== Required decrease in par value..................................... $ 2,812,606 ========== Entry to conform par value of common stock: Common stock....................................................... 2,812,606 Paid in Capital................................................. 2,812,606 Summary of pro forma entries above: Common Stock....................................................... 2,883,666 Paid in Capital................................................ 1,153,867 Treasury Stock................................................. 1,729,799 18

(4) Authorized, issued and outstanding share information is as follows at March 31, 2000: - ------------------------------------------------------------------------------------------------------------------------------------ NBT BSB NBT/BSB Pro forma Pioneer American NBT/BSB/ Pioneer American Pro forma - ------------------------------------------------------------------------------------------------------------------------------------ PREFERRED - ------------------------------------------------------------------------------------------------------------------------------------ Authorized 2,500,000 2,500,000 2,500,000 -- 5,000,000 - ------------------------------------------------------------------------------------------------------------------------------------ Issued and Outstanding -- -- -- -- -- - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ COMMON - ------------------------------------------------------------------------------------------------------------------------------------ Par value $0.01 $0.01 $0.01 $1.00 $0.01 - ------------------------------------------------------------------------------------------------------------------------------------ Authorized 30,000,000 30,000,000 30,000,000 30,000,000 100,000,000 - ------------------------------------------------------------------------------------------------------------------------------------ Issued 18,623,435 11,430,761 39,136,525 2,935,367 44,306,599 - ------------------------------------------------------------------------------------------------------------------------------------ Outstanding 18,100,868 10,256,545 38,613,958 2,864,307 43,784,032 - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ (5) The unaudited pro forma condensed combined balance sheet at March 31, 2000, reflects anticipated non-recurring merger and integration costs for both the Pioneer American and BSB mergers. Costs related to the Pioneer American merger are estimated to be in the range of $4.6 million to $5.6 million ($3.3 million to $4.3 million after taxes). Costs related to the BSB merger are estimated to be in the range of $16.0 million to $17.0 million ($11.5 million to $12.5 million after taxes). These estimates include primarily investment banking, legal, accounting, printing, data processing and system integration costs, and employee and contract termination costs. Anticipated merger and integration cost estimates are not included in the unaudited pro forma condensed combined statements of income for any of the periods presented. The pro forma statements do not reflect potential expense reductions or revenue enhancements expected to be realized subsequent to consummation of the mergers. The unaudited pro forma condensed combined balance sheet at March 31, 2000 only reflects merger and integration costs related to the Lake Ariel merger that were incurred through March 31, 2000. It is anticipated that there will be an additional $5.0 million of merger and integration costs incurred in the future in connection with the Lake Ariel merger. These additional costs are not recognized in the unaudited pro forma condensed combined balance sheet at March 31, 2000. The entries to record the anticipated merger and integration costs on the unaudited pro forma condensed combined balance sheet are as follows: BSB --- Current tax receivable............................................. 4,500,000 Retained earnings.................................................. 12,000,000 Other liabilities.............................................. 16,500,000 Pioneer American ---------------- Current tax receivable............................................. 1,300,000 Retained earnings.................................................. 3,800,000 Other liabilities.............................................. 5,100,000 19

PART II. INFORMATION NOT REQUIRED IN PROSPECTUS ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION. SEC Registration Fee...................................... $ 1,200 Printing Expenses......................................... 500 Legal Fees and Expenses................................... 10,000 Accounting Fees and Expenses.............................. 15,000 Miscellaneous............................................. 300 ------ Total..................................................... $27,000 ====== The foregoing amounts are the best estimates of NBT. ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS. NBT's Bylaws provide as follows: ARTICLE VI. INDEMNIFICATION OF DIRECTORS AND OFFICERS Section 1. Each person who was or is made a party or is threatened to be made a party to or is otherwise involved in any action, suit or proceeding, whether civil, criminal, administrative or investigative (hereinafter a "proceeding"), by reason of the fact that he or she is or was a director or an officer of the Corporation or is or was serving at the request of the Corporation as a director of another corporation or of a partnership, joint venture, trust or other enterprise, or as a plan fiduciary with respect to an employee benefit plan (hereinafter an "indemnitee"), whether the basis of such proceeding is alleged action in an official capacity as a Director, officer, or plan fiduciary or in any other capacity while serving as a Director, officer or plan fiduciary, shall be indemnified and held harmless by the Corporation to the fullest extent authorized by the Delaware General Corporation Law, as the same exists or may hereafter be amended, against all expense, liability and loss (including attorneys' fees, judgments, fines, ERISA excise taxes or penalties and amounts paid in settlement) reasonably incurred or suffered by such indemnitee in connection therewith; provided, however, that, except as provided in Section 3 of this Article VI with respect to proceedings to enforce rights to indemnification, the Corporation shall indemnify any such indemnitee in connection with a proceeding (or part thereof) initiated by such indemnitee only if such proceeding (or part thereof) was authorized by the Board of Directors of the Corporation. Section 2. The right to indemnification conferred in Section 1 of this Article VI shall include the right to be paid by the Corporation the expenses (including attorney's fees) incurred in defending any such proceeding in advance of its final disposition (hereinafter an "advancement of expenses"); provided, however, that, if the Delaware General Corporation Law requires, an advancement of expenses incurred by an indemnitee in his or her capacity as a director or officer (and not in any other capacity in which service was or is rendered by such indemnitee, including, without limitation, service to an employee benefit plan) shall be made only upon delivery to the Corporation of an undertaking (hereinafter an "undertaking"), by or on behalf of such indemnitee, to repay all amounts so advanced if it shall ultimately be determined by final judicial decision from which there is no further right to appeal (hereinafter a "final adjudication") that such indemnitee is not entitled to be indemnified for such expenses under this Section 2 or otherwise. The rights to indemnification and to the advancement of expenses conferred in Sections 1 and 2 of this Article VI shall be contract rights and such rights shall continue as to an indemnitee who has ceased to be a Director or officer and shall inure to the benefit of the indemnitee's heirs, executors and administrators. Section 3. If a claim under Sections 1 or 2 of this Article VI is not paid in full by the Corporation within sixty (60) days after a written claim has been received by the Corporation, except in the case of a claim for an advancement II-1

of expenses, in which case the applicable period shall be twenty (20) days, the indemnitee may at any time thereafter bring suit against the Corporation to recover the unpaid amount of the claim. If successful in whole or in part in any such suit, or in a suit brought by the Corporation to recover an advancement of expenses pursuant to the terms of an undertaking, the indemnitee shall be entitled to be paid also the expense of prosecuting or defending such suit. In (i) any suit brought by the indemnitee to enforce a right to indemnification hereunder (but not in a suit brought by the indemnitee to enforce a right to an advancement of expenses) it shall be a defense that, and (ii) in any suit brought by the Corporation to recover an advancement of expenses pursuant to the terms of an undertaking, the Corporation shall be entitled to recover such expenses upon a final adjudication that, the indemnitee has not met any applicable standard for indemnification set forth in the Delaware General Corporation Law. Neither the failure of the Corporation (including its Board of Directors, independent legal counsel, or its stockholders) to have made a determination prior to the commencement of such suit that indemnification of the indemnitee is proper in the circumstances because the indemnitee has met the applicable standard of conduct set forth in the Delaware General Corporation Law, nor an actual determination by the Corporation (including its Board of Directors, independent legal counsel, or its stockholders) that the indemnitee has not met such applicable standard of conduct, shall create a presumption that the indemnitee has not met the applicable standard of conduct or, in the case of such a suit brought by the indemnitee, be a defense to such suit. In any suit brought by the indemnitee to enforce a right to indemnification or to an advancement of expenses hereunder, or brought by the Corporation to recover an advancement of expenses pursuant to the terms of an undertaking, the burden of proving that the indemnitee is not entitled to be indemnified, or to such advancement of expenses, under this Section 15 or otherwise shall be on the Corporation. Section 4. The rights to indemnification and to the advancement of expenses conferred in this Article VI shall not be exclusive of any other right which any person may have or hereafter acquire under any statute, the Corporation's Certificate of Incorporation, By-Laws, agreement, vote of stockholders or disinterested Directors or otherwise. Section 5. The Corporation may maintain insurance, at its expense, to protect itself and any Director, officer, employee or agent of the Corporation or of another corporation, partnership, joint venture, trust or other enterprise against any expense, liability or loss, whether or not the Corporation would have the power to indemnify such person against such expense, liability or loss under the Delaware General Corporation Law. Section 6. The Corporation may, to the extent authorized from time to time by the Board of Directors, grant rights to indemnification and to the advancement of expenses to any employee or agent of the Corporation, or any person serving at the request of the Corporation as an officer, employee or agent of another entity, to the fullest extent of the provisions of this Section with respect to the indemnification and advancement of expenses of Directors and officers of the Corporation. ITEM 16. EXHIBITS. An Exhibit Index, containing a list of all exhibits filed with this Registration Statement, is included beginning on page II-6. ITEM 17. UNDERTAKINGS. The undersigned registrant hereby undertakes as follows: (1) to file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement: (i) to include any prospectus required by Section 10(a)(3) of the Securities Act of 1933; II-2

(ii) to reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement; (iii) to include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement. (2) that, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. (3) that, for the purpose of determining any liability under the Securities Act, each filing of the Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 that is incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of securities at that time shall be deemed to be the initial bona fide offering thereof. (4) to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of Regulation S-X is not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information. (5) that insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the provisions described under Item 15 above, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue. (6) to remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering. II-3

SIGNATURES Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Norwich, New York on this 27th day of June, 2000. NBT Bancorp Inc. /s/ Daryl R. Forsythe --------------------- By: Daryl R. Forsythe President and Chief Executive Officer KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Daryl R. Forsythe and Michael J. Chewens, and each of them, such person's true and lawful attorneys-in-fact and agents with full power of substitution and resubstitution, for such person and in such person's name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Securities and Exchange Commission, granting unto each said attorneys-in-fact and agents, full power and authority to do and perform each and every act and thing requisite and necessary to be done, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that any said attorneys-in-fact and agents, or either of them, or any substitute of them, 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 CAPACITY DATE - --------- -------- ---- /s/ Daryl R. Forsythe President, Chief Executive Officer June 27, 2000 - -------------------------------- and Director (Principal Executive Daryl R. Forsythe Officer) /s. Michael J. Chewens Executive Vice President, June 27, 2000 - -------------------------------- Chief Financial Officer, and Treasurer Michael J. Chewens of NBT and NBT Bank (Principal Financial and Accounting Officer) /s/ Everett A. Gilmour Chairman of the Board of Directors June 27, 2000 - -------------------------------- Everett A. Gilmour /s/ J. Peter Chaplin Director June 27, 2000 - -------------------------------- J. Peter Chaplin /s/ Peter B. Gregory Director June 27, 2000 - -------------------------------- Peter B. Gregory /s/ William C. Gumble Director June 27, 2000 - -------------------------------- William C. Gumble II-4

/s/ Bruce D. Howe Director June 27, 2000 - -------------------------------- Bruce D. Howe Director _______, 2000 - ------------------------------- Andrew S. Kowalczyk, Jr. Director _______, 2000 - ------------------------- Dan B. Marshman /s/ John G. Martines Director June 27, 2000 - -------------------- John G. Martines Director _______, 2000 - ------------------------- John C. Mitchell /s/ William L. Owens Director June 27, 2000 - -------------------- William L. Owens Director _______, 2000 - ------------------------- Paul O. Stillman II-5

EXHIBIT INDEX Exhibit No. Description and Method of Filing - ------ -------------------------------- 5 Opinion of Duane, Morris & Heckscher LLP regarding the legality of the shares of Common Stock being registered (filed herewith) 23.1 Consent of KPMG LLP, independent auditors for NBT Bancorp Inc. (filed herewith) 23.2 Consent of KPMG LLP, independent auditors for Pioneer American Holding Company Corp. (filed herewith) 23.3 Consent of PricewaterhoseCoopers LLP, independent auditors for BSB Bancorp, Inc. (filed herewith) 23.4 Consent of Duane, Morris & Heckscher LLP (contained in their opinion filed as Exhibit 5) 24 Power of Attorney (reference is made to the signature page of the Registration Statement)


                                                                       EXHIBIT 5


                          DUANE, MORRIS & HECKSCHER LLP
                         1667 K STREET, N.W., SUITE 700
                           WASHINGTON, D.C. 20006-1608
                                 (202) 776-7800



                                  June 27, 2000


NBT Bancorp Inc.
52 South Broad Street
Norwich, New York 13815

Gentlemen:

         We have acted as counsel to NBT Bancorp Inc. ("NBT") in connection with
the registration of 420,989 shares of NBT common stock, $.01 par value per share
("Common  Stock"),  on behalf of and for the  resale by David T.  Griffith  (the
"Shares").  In this regard,  we are also acting as counsel to NBT in  connection
with the Registration Statement on Form S-3 (the "Registration Statement") to be
filed by NBT with the  Securities  and  Exchange  Commission  for the purpose of
registering  the Shares  under the  Securities  Act of 1933,  as  amended.  This
opinion is being  furnished  for the purpose of being filed as an exhibit to the
Registration Statement.

         In connection with this opinion, we have examined, among other things:

         (1)      a copy certified to our satisfaction of the share certificates
                  issued by NBT to Griffith  and to Hoover and Company as escrow
                  agent for the Shares;

         (2)      a copy  certified to our  satisfaction  of the  Certificate of
                  Incorporation,  as amended, and the bylaws of NBT as in effect
                  on the date hereof;

         (3)      copies certified to our satisfaction of resolutions adopted by
                  the  Board of  Directors  of NBT on March 9,  2000,  including
                  resolutions approving the Registration Statement; and

         (4)      such other documents,  corporate proceedings,  and statutes as
                  we considered necessary to enable us to furnish this opinion.

         We have assumed the  authenticity  of all documents  submitted to us as
originals,  the  genuineness  of all  signatures,  the legal capacity of natural
persons, and the conformity to the originals of all documents submitted to us as
copies.  In making our  examination of any  documents,  we have assumed that all
parties other than NBT had the  corporate  power and authority to enter into and
perform all obligations thereunder and, as to such parties, we have also assumed
the execution and delivery of such documents and the validity and binding effect
and  enforceability  thereof.  We  have  assumed  that  the  certifications  and
representations  dated  earlier than the date hereof on which we have  expressed
reliance  herein  continue  to  remain  accurate,  insofar  as  material  to our
opinions, from such earlier date through the date hereof.

         Based upon the foregoing,  we are of the opinion that the Shares of NBT
Common Stock have been duly authorized and validly issued and are fully paid and
nonassessable shares of NBT Common Stock.



NBT Bancorp Inc. June 27, 2000 Page 2 We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to us under the caption "Legal Matters" in the Prospectus forming a part of the Registration Statement. Very truly yours, /s/ Duane, Morris & Heckscher LLP


                                                                    EXHIBIT 23.1


                         CONSENT OF INDEPENDENT AUDITORS


The Board of Directors
NBT Bancorp Inc.:

         We consent to incorporation by reference in the registration  statement
on Form S-3 of NBT Bancorp Inc.  related to the registration of shares on behalf
of and for Mr. David T. Griffith, filed by NBT Bancorp Inc. under the Securities
Act of 1933 of our audit  report  dated  January 21,  2000,  with respect to the
consolidated  balance  sheets of NBT Bancorp Inc. and  subsidiary as of December
31,  1999  and  1998,  and  the  related  consolidated   statements  of  income,
stockholders'  equity, cash flows and comprehensive income for each of the years
in the  three-year  period ended  December 31, 1999 which report  appears in the
December 31, 1999 annual report on Form 10-K of NBT Bancorp  Inc.,  incorporated
by  reference  herein,  and to the  reference  to our  firm  under  the  heading
"Experts" in the registration statement referred to above.

         We consent to incorporation by reference in the registration  statement
on Form S-3 of NBT Bancorp Inc.  related to the registration of shares on behalf
of and for Mr. David T. Griffith, filed by NBT Bancorp Inc. under the Securities
Act of 1933 of our audit  report  dated  March 10,  2000,  with  respect  to the
supplemental consolidated balance sheets of NBT Bancorp Inc. and subsidiaries as
of  December  31,  1999 and  1998,  and the  related  supplemental  consolidated
statements of income,  stockholders' equity, cash flows and comprehensive income
for each of the years in the  three-year  period  ended  December 31, 1999 which
report appears in the Current Report on Form 8-K dated March 31, 2000,  filed by
NBT Bancorp Inc., incorporated by reference herein.



KPMG LLP

Syracuse, New York
June 26, 2000


                                                                    EXHIBIT 23.2

                         CONSENT OF INDEPENDENT AUDITORS

The Board of Directors
Pioneer American Holding Company Corp.

We consent to incorporation  by reference in the registration  statement on Form
S-3 of NBT Bancorp Inc.,  related to the registration of shares on behalf of and
for Mr. David T. Griffith, filed by NBT Bancorp Inc. under the Securities Act of
1933, of our audit report dated January 21, 2000,  relating to the  consolidated
balance sheets of Pioneer  American  Holding  Company Corp. and subsidiary as of
December  31,  1999  and  1998,  and  the  related  consolidated  statements  of
operations,  changes  in  stockholders'  equity,  and cash flows for each of the
years in the  three-year  period ended December 31, 1999 which report appears in
the December  31, 1999 annual  report on Form 10-K of Pioneer  American  Holding
Company Corp.,  and to the reference to our firm under the heading  "Experts" in
the Prospectus.


/s/ KPMG LLP
KPMG LLP
Philadelphia, Pennsylvania
June 26, 2000


                                                                    EXHIBIT 23.3

                       CONSENT OF INDEPENDENT ACCOUNTANTS


We  hereby  consent  to the  incorporation  by  reference  in  the  registration
statement on Form S-3 of NBT Bancorp Inc., related to the registration of shares
on behalf of and for Mr. David T. Griffith,  filed by NBT Bancorp Inc. under the
Securities  Act of 1933, of our report dated  January 21, 2000,  relating to the
financial  statements  of BSB Bancorp,  Inc.,  which  appears in the 1999 Annual
Report to  Shareholders  which is incorporated by reference in its Annual Report
on Form 10-K for the year  ended  December  31,  1999.  We also  consent  to the
references to us under the heading "Experts" in such registration statement.


/s/ PricewaterhouseCoopers LLP
PricewaterhouseCoopers LLP
Syracuse, New York
June 26, 2000