First Interstate BancSystem (FIBK) S-4 Registration of securities issued in business combination transactions

Exhibit 8.2

LAW OFFICES SILVER, FREEDMAN, TAFF & TIERNAN LLP A LIMITED LIABILITY PARTNERSHIP INCLUDING PROFESSIONAL CORPORATIONS 3299 K STREET, N.W., SUITE 100 WASHINGTON, D.C. 20007
(202)295-4500 WWW.SFTTLAW.COM	TELECOPIER NUMBER (202)337-5502 PHONE NUMBER (202)295-4500

                    , 2018

Board of Directors

Community 1^st Bank

707 North Post Road

Post Falls, Idaho 83854

Re: Acquisition of Community 1^st Bank by First Interstate BancSystem, Inc.

Ladies and Gentlemen:

We have acted as special tax counsel to Community 1^st Bank, an Idaho-chartered bank (“CMYF”), in connection with the planned merger (the “Merger”) of CMYF with and into First Interstate Bank, a Montana-chartered bank (“Purchaser Bank”) and wholly-owned subsidiary of First Interstate BancSystem, Inc., a Montana corporation (“Purchaser”), pursuant to an Agreement and Plan of Merger (the “Merger Agreement”) by and between Purchaser, Purchaser Bank and CMYF, dated as of October 11, 2018.

In connection with this opinion, we have reviewed: (i) the Merger Agreement; (ii) the Registration Statement on FormS-4 filed by Purchaser with the Securities and Exchange Commission in connection with the Merger (the “Registration Statement”) and the Proxy Statement/Prospectus included therein; and (iii) the certificates of Officers of CMYF and Purchaser as to certain factual matters, dated the date hereof (the “Certificates”), and have assumed that such statements and representations will be complete and accurate as of the effective time of the Merger.

We have relied, with the consent of CMYF and Purchaser , upon the accuracy and completeness of the Certificates (which Certificates we have neither investigated nor verified). We also have relied upon the accuracy of the Registration Statement.

In rendering this opinion, we have considered the applicable provisions of the Internal Revenue Code of 1986, as amended (the “Code”), Treasury Regulations promulgated thereunder, interpretive rulings of the Internal Revenue Service (the “IRS”), pertinent judicial authorities and such other authorities as we have considered relevant as of the date hereof (hereinafter, collectively referred to as “Current Law”).

Based upon and subject to the foregoing, and subject to the limitations, qualifications, exceptions and assumptions set forth herein and in the Registration Statement under “Material U.S. Federal Income

Community 1^st Bank

                    , 2018

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Tax Consequences of the Merger,” we are of the opinion that under Current Law, the Merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Code. We hereby confirm that the discussion contained in the Registration Statement under the caption “Material U.S. Federal Income Tax Consequences of the Merger,” subject to the limitations, qualifications, and assumptions described therein, constitutes our opinion of the material U.S. federal income tax consequences of the Merger.

This opinion is based on Current Law and it represents our best judgment, but it has no binding effect or official status of any kind, and no assurance can be given that contrary positions may not be taken by the IRS or a court concerning the issues. It is possible that the U.S. Congress could enact new law, or that Department of the Treasury or the IRS could issue new regulations or guidance, after the date hereof that would be inconsistent with the opinion expressed herein. It is possible that courts of competent jurisdiction could issue decisions after the date hereof which would be inconsistent with the opinion expressed herein. Any changes in law could have retroactive effect.

We express our opinion herein only as to those matters specifically set forth above and no opinion should be inferred as to the tax consequences of the Merger under any state, local or foreign law, or with respect to other areas of United States federal taxation.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to us under the heading “Description of the Merger – Material U.S. Federal Income Tax Consequences of the Merger” and “Legal Matters” in the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act of 1933.

Very truly yours,

SILVER, FREEDMAN, TAFF & TIERNAN LLP