8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (date of earliest event reported): March 19, 2010

FIRST INTERSTATE BANCSYSTEM, INC.

(Exact name of registrant as specified in its charter)

Montana	000-49733	81-0331430
(State or other jurisdiction of incorporation)	(Commission File No.)	(IRS Employer Identification No.)

401 North 31st Street, Billings, MT	59116
(Address of principal executive offices)	(Zip Code)

(406) 255-5390
(Registrant’s telephone number, including area code)

Not Applicable
(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

TABLE OF CONTENTS

EX-10.1

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

     On March 19, 2010, the Compensation Committee of the Board of Directors of First Interstate BancSystem, Inc. (the “Company”), pursuant to authority delegated by the Board of Directors, approved and adopted an amendment (the “Amendment”) to the Company’s 2006 Equity Compensation Plan (the “Plan”). A summary of the Amendment is contained below and is qualified in its entirety by reference to the complete text of the Amendment, a copy of which is attached to this current report as Exhibit 10.1 and is incorporated herein by reference.

     The Amendment becomes effective upon, and is subject to, the closing of the Company’s proposed initial public offering of shares of its Class A common stock, pursuant to its Registration Statement on Form S-1 (the “Offering”). The Amendment (i) confirms that all stock option and restricted stock awards outstanding as of the Offering are exercisable for shares of the Company’s Class B common stock, and (ii) provides that any and all future awards that may be made under the Plan after the Offering will be exercisable for shares of the Company’s Class A common stock. Except as modified by the Amendment, all other terms of the Plan remain in full force and effect.

Item 9.01 Financial Statements and Exhibits.

Exhibits
10.1	Amendment to the First Interstate BancSystem, Inc. 2006 Equity Compensation Plan, dated March 19, 2010.

SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: March 19, 2010

FIRST INTERSTATE BANCSYSTEM, INC.
By:	/s/ LYLE R. KNIGHT
	Lyle R. Knight
	President and Chief Executive Officer

EX-10.1

Exhibit 10.1

Amendment
to the
First Interstate BancSystem, Inc.
2006 Equity Compensation Plan

     This Amendment (the “Amendment”) by First Interstate BancSystem, Inc., a Montana corporation (the “Company”), to its 2006 Equity Compensation Plan (the “2006 Plan”) is entered into by the Company as of March 19, 2010.

     Whereas, the Company previously adopted the 2006 Plan pursuant to which the Company may grant equity awards to its directors, officers and other employees in an effort to attract, retain and motivate individuals who are expected to make important contributions to the Company.

     Whereas, in connection with the Company’s proposed initial public offering, the Compensation Committee of the Board of Directors of the Company (the “Board”), pursuant to authority delegated by the Board, has determined that it is in the best interests of the Company and its shareholders to amend the 2006 Plan in accordance with the provisions hereof.

     Now, therefore, based on the foregoing recitals, the Company hereby agrees as follows:

     1. Effective as of, and subject to, the closing of the Company’s proposed initial public offering of shares of its Class A common stock, pursuant to its Registration Statement on Form S-1 (SEC File No. 333-164380), and listing of such shares for trading on The NASDAQ Stock Market LLC, the definition of “Common Stock” in section 2.6 of the 2006 Plan shall be revised to read in its entirety as follows:

2.6 Common Stock. The term “Common Stock” means common stock of FIBS. Stock Option Benefits and Restricted Stock Benefits that are outstanding as of the Offering shall be exercisable or otherwise deemed to consist of shares of Class B common stock. Any and all Benefits that may be granted under this Plan after the Offering shall be exercisable or otherwise shall consist of shares of Class A common stock.

     2. Except as modified in this Amendment, all other terms of the 2006 Plan shall remain in full force and effect.

[Signature page follows]

     IN WITNESS WHEREOF, the undersigned has executed this Amendment effective as of the date first above written.

COMPANY: First Interstate BancSystem, Inc., a Montana corporation
By:	/s/ Terrill R. Moore
	Terrill R. Moore
	Executive Vice President & Chief Financial Officer