Exhibit 10.20
FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT
     This First Amendment to Stock Purchase Agreement (“First Amendment”) is
effective as of January 10, 2008 by and among First Interstate BancSystem, Inc.
(“FIBS”) and Christen Group, Inc. formerly known as First Western Bancorp, Inc.
(“First Western”).
RECITALS:

  A.   FIBS and First Western entered a Stock Purchase Agreement effective as of
September 18, 2007 (the “Agreement”) providing for, among other things, the
purchase by FIBS of all of the issued and outstanding common stock of certain
subsidiaries of First Western.     B.   The Agreement contemplated, among other
things, certain adjustments to the loan loss reserve of the Banks.     C.   The
parties desire to amend the provisions relating to the loan loss reserve and the
Purchase Price to give effect to certain accounting, tax and other
considerations at the mutual agreement of the parties.         IN CONSIDERATION
OF THE ABOVE, the parties agree as follows:

1.0 Definitions. Capitalized terms used in this First Amendment and not
otherwise defined are accorded the meaning given such terms in the Agreement.
2.0 Amendment to Section 5.6. Section 5.6 is amended by inserting (1) in subpart
(b)(i) for the dollar amount “$4,950,000.00” the dollar amount of
“$4,500,000.00” and, (2) in subpart (b)(ii) for the dollar amount
“$6,050,000.00” the dollar amount of “$4,200,000.00”.
3.0 Amendment to Purchase Price. Section 2.2.1 of the Agreement is amended by
replacing the phrase and dollar amount “Two Hundred Fifty-One Million Three
Hundred Seventy-Seven Thousand Three Hundred Ninety-Two Dollars
($251,377,392.00)” with the phrase and dollar amount “Two Hundred Forty-Nine
Million Seventy-Seven Thousand Three Hundred Ninety-Two Dollars
($249,077,392.00)”.
4.0 No Further Effect. This First Amendment is intended to be and shall be
construed as an integral part of the Agreement. Except as expressly amended by
this First Amendment, the Agreement remains in full force and effect unimpaired
by this First Amendment.
(Remainder of page blank. Signature page follows.)

      FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT   Page 1

 

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              FIRST INTERSTATE BANCSYSTEM, INC.
 
       
 
  By:   /s/ Lyle R. Knight
 
       
 
      Lyle R. Knight
 
      Its: Chief Executive Officer
 
            CHRISTEN GROUP,INC.
f/k/a FIRST WESTERN BANCORP., INC.
 
       
 
  By:   /s/ Paul Christen
 
       
 
      Paul Christen
 
      Its: Chief Executive Officer

      FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT   Page 2