EXHIBIT 10.64


NOTWITHSTANDING  ANY  OTHER  PROVISION  OF  THIS  AGREEMENT,  NO  SHARES  OF THE
COMPANY'S  STOCK MAY BE ISSUED  PURSUANT  HERETO UNLESS IN  COMPLIANCE  WITH THE
COMPANY'S  1988  STOCK  OPTION  PLAN AND  WITH  APPLICABLE  SECURITIES  LAWS AND
REGULATIONS.


                                                  SIERRA TAHOE BANCORP
                                            INCENTIVE STOCK OPTION AGREEMENT


     THIS INCENTIVE STOCK OPTION  AGREEMENT (the  "Agreement") is dated December
20, 1995, and is entered into by and between SIERRA TAHOE BANCORP,  a California
corporation (the "Company") and Martin R. Sorensen ("Optionee");

                                                       WITNESSETH:
     WHEREAS,  pursuant  to the  1988  Stock  Option  Plan of the  Company  (the
"Plan"),  the Board of  Directors  of the Company  have  authorized  granting to
Optionee a stock option  ("Option")  to purchase all or any part of Six Thousand
(6,000) authorized but unissued shares of the Company's common stock for cash at
the price of Eleven  Dollars  and  Twenty  Five  Cents  ($11.25)  per share (the
"Option"),  such Option to be for the term and upon the  conditions  hereinafter
stated;
     NOW, THEREFORE, it is hereby agreed:
     1.       Grant of Option
              Pursuant to said action of the Board of  Directors at a meeting of
the Board on December 20, 1995,  and pursuant to  authorizations  granted by all
appropriate  regulatory and governmental  agencies, the Company hereby grants to
Optionee the Option to purchase, upon and subject to the terms and conditions of
the Plan,  which is incorporated  in full herein by this  reference,  all or any
part of Six Thousand (6,000) shares of the Company's  Common Stock  (hereinafter
called  the  "Stock")  at the price of Eleven  Dollars  and  Twenty  Five  Cents
($11.25) per share,  which price is not less than one hundred  percent (100%) of
the fair  market  value of the  stock as of the date of  action  of the Board of
Directors granting this Option. This Option is intended to be an incentive stock
option issued pursuant to Section 422A of the Internal Revenue Code of 1986.




<PAGE>



     2.       Exercisability
              This Option shall be exercisable as to 1,200 shares on or after 12
months,  an additional  1,200 shares on or after 24 months,  an additional 1,200
shares on or after 36 months,  an additional 1,200 shares on or after 48 months,
and an  additional  1,200 shares at 60 months.  Any  unexercised  shares must be
exercised  or  forfeited  at the  conclusion  of 60 months and one (1) day after
December  20,  1995,  unless this Option has  expired or  terminated  earlier in
accordance  with the provisions  hereof.  Shares as to which this Option becomes
exercisable  pursuant to the  foregoing  provision  may be purchased at any time
prior to expiration of this Option.
     3.       Exercise of Option
              This Option may be  exercised by written  notice  delivered to the
Company's Chief Financial Officer,  Controller or Shareholder  Relations Officer
stating  the  number  of  shares  with  respect  to which  this  Option is being
exercised,  together with sufficient cash in the amount of the purchase price of
such  shares.  Not less than ten (10)  shares may be  purchased  at any one time
unless the number purchased is the total remaining number which may be purchased
under this Option and in no event may the Option be  exercised  with  respect to
fractional shares. Upon exercise,  Optionee shall make appropriate  arrangements
and shall be responsible for the withholding of any federal and state taxes then
due.
     4.       Cessation of Employment
              Except as provided in Paragraphs 2 and 5 hereof, if Optionee shall
cease to be employed by the Company or a subsidiary  corporation  for any reason
other than  Optionee's  death or disability (as defined in Section  105(d)(4) of
the Internal  Revenue Code of 1986,  as amended from time to time),  this Option
shall expire three (3) months  thereafter  or that period set forth in Paragraph
2,  whichever  is earlier.  During the  three-month  period this Option shall be
exercisable only as to those installments, if any,

                                                            2


<PAGE>



which had  accrued as of the date when  Optionee  ceased to be  employed  by the
Company or the subsidiary corporation and not thereafter.
     5.       Termination of Employment for Cause
              If   Optionee's   employment   by  the  Company  or  a  subsidiary
corporation  is  terminated  for cause,  this Option shall  expire  immediately,
unless Optionee promptly petitions the Board of Directors of the Company and the
vested  Option(s) are  reinstated  by the Board of Directors  within thirty (30)
days of such  termination  by giving  written  notice of such  reinstatement  to
Optionee at his last known address. In the event of such reinstatement, Optionee
may exercise this Option only to such extent, for such time, and upon such terms
and  conditions  as if  Optionee  had ceased to be  employed by the Company or a
subsidiary corporation upon the date of such termination for a reason other than
cause or death.  Termination  for cause shall be defined to include  termination
for malfeasance or gross  misfeasance in the performance of duties or conviction
of illegal  activity in connection  therewith or any conduct  detrimental to the
interest of the Company,  or a subsidiary  corporation,  and, in any event,  the
determination  of the Board of Directors with respect thereto shall be final and
conclusive.
     6.       Nontransferability; Disability or Death of Optionee
              This  Option  shall not be  transferable  except  by  testamentary
disposition or by the laws of descent and  distribution and shall be exercisable
during Optionee's lifetime only by Optionee.  If Optionee dies while employed by
the Company or a  subsidiary  corporation,  or during the three (3) month period
referred to in  Paragraph 4 hereof,  this Option shall expire one (1) year after
the date of  Optionee's  death or on the day  specified  in  Paragraph 2 hereof,
whichever is earlier.  After Optionee's  death but before such  expiration,  the
persons to whom  Optionee's  rights  under  this  Option  shall  have  passed by
testamentary  disposition or by the applicable laws of descent and  distribution
or the executor or  administrator  of Optionee's  estate shall have the right to
exercise this Option as to those shares for which installments had accrued under
Paragraph 2 hereof as of the date on which Optionee ceased to be employed by the
Company or a subsidiary  corporation.  If Optionee  shall  terminate  employment
because of disability (as that term is

                                                            3


<PAGE>



defined in Section  105(d)(4) of the Internal  Revenue Code of 1986,  as amended
from time to time), Optionee may exercise this Option to the extent he or she is
entitled to do so at the date of termination, or at any time within one (1) year
of the date of  termination,  but in no event later than the expiration  date in
Paragraph 2.
     7.       Employment
              This  Agreement  shall not  obligate  the Company or a  subsidiary
corporation to employ Optionee for any period, nor shall it interfere in any way
with the right of the Company or a subsidiary  corporation to reduce  Optionee's
compensation.
     8.       Privileges of Stock Ownership
              Optionee shall have no rights as a stockholder with respect to the
Company's stock subject to this Option until the date of payment and issuance of
stock certificates to Optionee pursuant to this Agreement. No adjustment will be
made for  dividends  or other  rights for which the record  date is prior to the
date such stock certificates is paid for and issued.
     9.       Modification and Termination by Board of Directors
              The rights of Optionee are subject to modification and termination
upon the occurrence of certain events as provided in the Plan.
     10.      Representations of Optionee
              No shares  issuable  upon the  exercise  of this  option  shall be
issued and delivered unless and until all applicable  requirements of applicable
state and federal law and of the Securities and Exchange  Commission  pertaining
to the issuance and sale of such shares, and all applicable listing requirements
of the securities exchanges,  if any, on which shares of the Company of the same
class are then  listed  shall have been  complied  with.  Upon  exercise  of any
portion of this Option, the person entitled to exercise the same may be required
to execute a  representation  letter with respect to compliance with federal and
applicable state securities laws. In addition, if the Optionee is an "affiliate"
for purposes of the  Securities  Act of 1933,  as that term is defined  therein,
there may be  additional  restrictions  on the  resale of  stock,  and  Optionee
therefore  agrees to ascertain what those  restrictions  are and to abide by the
restrictions  and other applicable  federal and state securities laws.  Optionee
understands  that the shares of stock purchased under this option may be subject
to holding periods and/or other  restrictions on resale.  The Company may, if it
deems appropriate,  issue stop transfer instructions against any shares of stock
purchased  upon  the  exercise  of this  option  and  affix  to any  certificate
representing such shares the legends which the Company deems appropriate.

     11.      Notices


<PAGE>



              Any notice to the Company  provided for in this Agreement shall be
addressed  to it in  care  of its  Chief  Financial  Officer  or  Controller  or
Shareholder  Relations  Officer at its main  office  and any notice to  Optionee
shall  be  addressed  to  Optionee's  address  on file  with  the  Company  or a
subsidiary corporation,  or to such other address as either may designate to the
other in  writing.  Any  notice  shall be  deemed  to be duly  given if and when
enclosed  in a  properly  sealed  envelope  and  addressed  as stated  above and
deposited,  postage prepaid,  with the United States Postal Service.  In lieu of
giving notice by mail as aforesaid,  any written notice under this Agreement may
be given to Optionee in person,  and to the Company by personal  delivery to its
Chief Financial Officer, Controller or Shareholder Relations Officer.
     IN WITNESS WHEREOF, the parties hereto have executed this Agreement.

OPTIONEE:


     /s/ Martin R. Sorensen
     Martin R. Sorensen


SIERRA TAHOE BANCORP,
a California Corporation ("Company")



By:  /s/ William T. Fike
     WILLIAM T. FIKE
Its: CEO/President

J:\lawyer\hr\incentiv.emp                              5

<PAGE>