SUMMARY OF RIGHTS TO PURCHASE
                  SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

The Board of Directors of NBT Bancorp Inc., a Delaware Corporation (the
"Company"), has declared a dividend distribution of one right ("Right") for each
outstanding share of Common Stock, par value $.01 per share ("Common Stock") of
the Company. The distribution is payable to stockholders of record on November
16, 2004. Each Right, when exercisable, entitles the registered holder to
purchase from the Company one one-thousandth of a share of Series A Junior
Participating Preferred Stock ("Preferred Stock") at a price of $70 per one
one-thousandth share (the "Purchase Price"), subject to adjustment. The
description and terms of the Rights are set forth in a Rights Agreement (the
"Rights Agreement") between the Company and Registrar and Transfer Company, as
Rights Agent (the "Rights Agent").

Initially, the Rights will be attached to all certificates representing shares
of Common Stock then outstanding, and no separate certificates evidencing the
Rights will be distributed. The Rights will separate from the Common Stock and a
distribution of Rights Certificates (as defined below) will occur upon the
earlier to occur of (i) 10 days following a public announcement that a person or
group of affiliated or associated persons (an "Acquiring Person") has acquired,
or obtained the right to acquire, beneficial ownership of 15% or more of the
outstanding shares of Common Stock (the "Stock Acquisition Date") or (ii) 10
business days (or such later date as the Board of Directors of the Company may
determine) following the commencement of, or the first public announcement of
the intention to commence, a tender offer or exchange offer the consummation of
which would result in the beneficial ownership by a person of 15% or more of the
outstanding shares of Common Stock (the earlier of such dates being called the
"Distribution Date").

Until the Distribution Date, (i) the Rights will be evidenced by the Common
Stock certificates, and will be transferred with and only with the Common Stock
certificates, (ii) new Common Stock certificates issued after November 16, 2004,
upon transfer or new issuance of the Common Stock will contain a notation
incorporating the Rights Agreement by reference, and (iii) the surrender for
transfer of any certificates for Common Stock outstanding will also constitute
the transfer of the Rights associated with the Common Stock represented by such
certificate.

The Rights are not exercisable until the Distribution Date and will expire at
the close of business on October 24, 2014, unless earlier redeemed or exchanged
by the Company as described below.

As soon as practicable following the Distribution Date, separate certificates
evidencing the Rights ("Rights Certificates") will be mailed to holders of
record of the Common Stock as of the close of business on the Distribution Date
and, thereafter, the separate Rights Certificates alone will evidence the
Rights. Except as otherwise determined by the Board of Directors of the Company,
only shares of Common Stock issued prior to the Distribution Date will be issued
with Rights.

In the event that a Person becomes the beneficial owner of 15% or more of the
then outstanding shares of Common Stock, each holder of a Right will, after the
end of a redemption period referred to below, have the right to exercise the
Right by purchasing, for an amount equal to the Purchase Price, Common Stock
(or, in certain circumstances, cash, property or other securities of the
Company) having a value equal to two times such amount. Notwithstanding any of
the foregoing, following the occurrence of the events set forth in this
paragraph, all Rights that are, or (under certain circumstances specified in the
Rights Agreement) were, beneficially owned by any Acquiring Person will be null
and void. However, Rights are not exercisable following the occurrence of the
events set forth above until such time as the Rights are no longer redeemable by
the Company as set forth below.



For example, at a Purchase Price of $70 per Right, each Right not owned by an
Acquiring Person (or by certain related parties) following an event set forth in
the preceding paragraph would entitle its holder to purchase $140 worth of
Common Stock (or other consideration, as noted above) for $70.

In the event that, at any time following the Stock Acquisition Date, (i) the
Company is acquired in a merger or other business combination transaction, or
(ii) 50% or more of the Company's assets or earning power is sold or
transferred, each holder of a Right (except Rights that previously have been
voided as set forth above) shall, after the expiration of the redemption period
referred to below, have the right to receive, upon exercise, common stock of the
acquiring company having a value equal to two times the Purchase Price of the
Right (e.g., common stock of the acquiring company having a value of $140 for
the $70 Purchase Price).

At any time after a person or group of affiliated or associated persons becomes
an Acquiring Person and prior to the acquisition by such person or group of 50%
or more of the outstanding Common Stock, the Board of Directors of the Company
may exchange the Rights (other than Rights owned by such person or group that
have become void), in whole or in part, at an exchange ratio of one share of
Common Stock per each outstanding Right or, in certain circumstances, other
equity securities of the Company that are deemed by the Board of Directors of
the Company to have the same value as shares of Common Stock, subject to
adjustment.

In general, the Board of Directors of the Company, may cause the Company to
redeem the Rights in whole, but not in part, at any time during the period
commencing on October 25, 2004, and ending on the tenth day following the Stock
Acquisition Date (the "Redemption Period") at a price of $.001 per Right
(payable in cash, Common Stock or other consideration deemed appropriate by the
Board of Directors of the Company). Under certain circumstances set forth in the
Rights Agreement, the decision to redeem the Rights will require the concurrence
of the two-thirds of Directors. After the Redemption Period has expired, the
Company's right of redemption may be reinstated if an Acquiring Person reduces
his beneficial ownership to 10% or less of the outstanding shares of Common
Stock in a transaction or series of transactions not involving the Company and
there are no other Acquiring Persons. Immediately upon the action of the Board
of Directors of the Company ordering redemption of the Rights, the Rights will
terminate and the only right of the holders of Rights will be to receive the
$.001 redemption price.

Until a Right is exercised, the holder thereof, as such, will have no rights as
a stockholder of the Company, including, without limitation, the right to vote
or to receive dividends. While the distribution of the Rights will not be
subject to federal taxation to stockholders or to the Company, stockholders may,
depending upon the circumstances, recognize taxable income in the event that the
Rights become exercisable for Common Stock (or other consideration) of the
Company or for common stock of the acquiring company as set forth above.


                                      * * *


A copy of the Rights Agreement has been filed with the U.S. Securities and
Exchange Commission as an Exhibit to a Current Report on Form 8-K. A copy of the
Rights Agreement is available free of charge from the Company. This summary
description of the Rights does not purport to be complete and is qualified in
its entirety by reference to the Rights Agreement.