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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
___________________________________________________________________________________________________________________________________________________ 
FORM 10-Q
_____________________________________________________________________________________________________________________________________________________ 

    Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
For the quarterly period ended September 30, 2021
OR
     Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
For the transition period from                   to                   
COMMISSION FILE NUMBER 001-34653
________________________________________________________________________________________________________ 
FIRST INTERSTATE BANCSYSTEM, INC.
(Exact name of registrant as specified in its charter)
________________________________________________________________________________________________________ 
Montana81-0331430
(State or other jurisdiction of
incorporation or organization)
(IRS Employer
Identification No.)
401 North 31st Street
Billings,MT59116-0918
(Address of principal executive offices)(Zip Code)
Registrant’s telephone number, including area code: (406) 255-5390
_________________________________________________________________________________________________ 

Securities registered pursuant to Section 12(b) of the Act:
Title of each classTrading Symbol(s)Name of each exchange on which registered
Class A common stock, no par valueFIBKNASDAQ
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.     Yes      No  
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files.)     Yes      No  
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.
Large accelerated filer  Accelerated filer
Non-accelerated filerSmaller reporting company
Emerging growth company
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).  Yes   No  
Indicate the number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date:
September 30, 2021 – Class A common stock41,715,627 
September 30, 2021 – Class B common stock20,515,516 




Quarterly Report on Form 10-Q
FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
Index
September 30, 2021
  Page Nos.
Item 1.
Item 2.
Item 3.
Item 4.
Item 1.
Item 1A.
Item 2.
Item 3.
Item 4.
Item 5.
Item 6.


















2

FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
CONSOLIDATED BALANCE SHEETS
(In millions, except share data)
(Unaudited)
September 30,
2021
December 31,
2020
Assets
Cash and due from banks$227.6 $261.4 
Interest bearing deposits in banks2,005.8 2,015.3 
Federal funds sold0.1 0.1 
Total cash and cash equivalents2,233.5 2,276.8 
Investment securities:
Available-for-sale4,403.6 4,008.7 
Held-to-maturity, net (estimated fair values of $1,632.5 and $55.0 at September 30, 2021 and December 31, 2020, respectively)
1,618.1 51.6 
Total investment securities6,021.7 4,060.3 
Mortgage loans held for sale, at fair value42.5 74.0 
Loans held for investment, net of deferred fees and costs9,622.5 9,807.5 
Allowance for credit losses135.1 144.3 
Net loans held for investment9,487.4 9,663.2 
Goodwill621.6 621.6 
Company-owned life insurance300.5 296.4 
Premises and equipment, net of accumulated depreciation297.3 312.3 
Core deposit intangibles, net of accumulated amortization43.7 51.2 
Accrued interest receivable52.9 51.1 
Mortgage servicing rights, net of accumulated amortization and impairment reserve27.0 24.0 
Other real estate owned (“OREO”)2.3 2.5 
Other assets241.8 215.3 
Total assets$19,372.2 $17,648.7 
Liabilities and Stockholders’ Equity
Deposits:
Non-interest bearing$5,617.9 $4,633.5 
Interest bearing10,389.4 9,583.5 
Total deposits16,007.3 14,217.0 
Securities sold under repurchase agreements1,007.5 1,091.4 
Accounts payable and accrued expenses146.0 144.4 
Accrued interest payable6.6 5.8 
Deferred tax liability, net17.4 27.2 
Long-term debt112.4 112.4 
Allowance for credit losses on off-balance sheet credit exposures3.2 3.7 
Subordinated debentures held by subsidiary trusts87.0 87.0 
Total liabilities17,387.4 15,688.9 
Stockholders’ equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued and outstanding as of September 30, 2021 or December 31, 2020
  
Common stock943.6 941.1 
Retained earnings1,026.9 962.1 
Accumulated other comprehensive income, net14.3 56.6 
Total stockholders’ equity1,984.8 1,959.8 
Total liabilities and stockholders’ equity$19,372.2 $17,648.7 
See accompanying notes to unaudited consolidated financial statements.
3

FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENTS OF INCOME
(In millions, except per share data)
(Unaudited)
 Three Months Ended September 30,Nine Months Ended September 30,
 2021202020212020
Interest income:
Interest and fees on loans$111.9 $112.3 $325.1 $336.4 
Interest and dividends on investment securities:
Taxable17.1 15.5 48.7 48.4 
Exempt from federal taxes1.4 0.6 4.2 1.6 
Interest on deposits in banks0.7 0.5 1.7 3.5 
Total interest income131.1 128.9 379.7 389.9 
Interest expense:
Interest on deposits1.9 3.4 6.4 15.2 
Interest on securities sold under repurchase agreements0.1 0.1 0.3 0.7 
Interest on other debt1.5 1.7 4.5 3.0 
Interest on subordinated debentures held by subsidiary trusts0.7 0.7 2.1 2.4 
Total interest expense4.2 5.9 13.3 21.3 
Net interest income126.9 123.0 366.4 368.6 
(Reversal of) provision for credit losses 5.2 (5.1)53.7 
Net interest income after provision for (reversal of) credit losses126.9 117.8 371.5 314.9 
Non-interest income:
Payment services revenues12.2 10.5 33.8 30.0 
Mortgage banking revenues11.6 14.3 32.8 39.4 
Wealth management revenues6.5 5.9 19.1 17.5 
Service charges on deposit accounts4.4 4.3 12.1 13.3 
Other service charges, commissions, and fees1.4 5.0 5.1 10.0 
Investment securities gains, net0.3 0.1 0.2 0.1 
Other income3.3 4.6 10.0 12.5 
Total non-interest income39.7 44.7 113.1 122.8 
Non-interest expense:
Salaries and wages42.0 46.0 122.6 130.1 
Employee benefits12.9 11.8 43.7 36.4 
Outsourced technology services8.2 8.4 24.7 24.5 
Occupancy, net7.3 7.2 21.7 21.3 
Furniture and equipment4.5 4.1 13.0 11.1 
OREO expense, net of income  (0.1)(0.4)
Professional fees2.7 2.9 9.3 8.6 
FDIC insurance premiums1.7 1.3 4.8 4.5 
Core deposit intangibles amortization2.4 2.7 7.4 8.3 
Other expenses17.6 15.1 49.6 45.7 
Acquisition related expenses6.6  6.6  
Total non-interest expense105.9 99.5 303.3 290.1 
Income before income tax expense60.7 63.0 181.3 147.6 
Income tax expense13.6 14.7 40.3 33.3 
Net income$47.1 $48.3 $141.0 $114.3 
Earnings per common share (Basic)$0.76 $0.76 $2.29 $1.78 
Earnings per common share (Diluted)0.76 0.76 $2.28 $1.78 
Weighted average common shares outstanding (Basic)61,673,656 63,764,474 61,641,342 64,184,832 
Weighted average common shares outstanding (Diluted)61,747,972 63,861,457 61,732,822 64,295,525 
See accompanying notes to unaudited consolidated financial statements.
4

FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(In millions)
(Unaudited)
 Three Months Ended September 30,Nine Months Ended September 30,
 2021202020212020
Net income$47.1 $48.3 $141.0 $114.3 
Other comprehensive (loss) income, before tax:
Investment securities available-for sale:
Change in net unrealized (losses) gains during period(13.4)(4.2)(81.0)69.9 
Reclassification adjustment for net gain included in income(0.3)(0.1)(0.2)(0.1)
Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity(2.5) 22.3  
Unrealized loss on derivatives3.2  2.3 0.2 
Defined benefit post-retirement benefits plans:
Change in net actuarial loss (0.1) (0.5)
Other comprehensive income (loss), before tax(13.0)(4.4)(56.6)69.5 
Changes in deferred taxes related to other comprehensive income (loss)3.2 1.1 14.3 (18.6)
Other comprehensive (loss) income, net of tax(9.8)(3.3)(42.3)50.9 
Comprehensive income, net of tax$37.3 $45.0 $98.7 $165.2 
See accompanying notes to unaudited consolidated financial statements.

5

FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS’ EQUITY
(In millions, except share and per share data)
(Unaudited)
Three Months Ended September 30,
Common
stock
Retained
earnings
Accumulated
other
comprehensive
income (loss)
Total
stockholders’
equity
Balance at June 30, 2021$941.6 $1,005.2 $24.1 $1,970.9 
Net income 47.1  47.1 
Other comprehensive loss, net of tax expense  (9.8)(9.8)
Common stock transactions:
574 common shares purchased and retired
    
1,782 non-vested common shares issued
    
12,620 non-vested common shares forfeited or canceled
    
2,324 stock options exercised, net of 0 shares tendered in payment of option price and income tax withholding amounts
    
Stock-based compensation expense2.0   2.0 
Common cash dividends declared ($0.41 per share)
 (25.4) (25.4)
Balance at September 30, 2021$943.6 $1,026.9 $14.3 $1,984.8 
Balance at June 30, 2020$1,021.2 $912.5 $65.2 $1,998.9 
Net income 48.3  48.3 
Other comprehensive loss, net of tax expense  (3.3)(3.3)
Common stock transactions:
1,445,300 common shares purchased and retired
(46.3)  (46.3)
924 non-vested common shares issued
    
4,735 non-vested common shares forfeited or canceled
    
5,143 stock options exercised, net of 0 shares tendered in payment of option price and income tax withholding amounts
0.1   0.1 
Stock-based compensation expense1.8   1.8 
Common cash dividends declared ($0.34 per share)
 (21.9) (21.9)
Balance at September 30, 2020$976.8 $938.9 $61.9 $1,977.6 

6

FIRST INTERSTATE BANCSYSTEM, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS’ EQUITY (continued)
(In millions, except share and per share data)
(Unaudited)
Nine Months Ended September 30,
Common
stock
Retained
earnings
Accumulated other
comprehensive
income (loss)
Total
stockholders’
equity
Balance at December 31, 2020$941.1 $962.1 $56.6 $1,959.8 
Net income 141.0  141.0 
Other comprehensive loss, net of tax expense  (42.3)(42.3)
Common stock transactions:
128,038 common shares purchased and retired
(5.4)  (5.4)
19,081 common shares issued
    
241,307 non-vested common shares issued
    
39,993 non-vested common shares forfeited or canceled
    
42,987 stock options exercised, net of 6,177 shares tendered in payment of option price and income tax withholding amounts
0.4   0.4 
Stock-based compensation expense7.5   7.5 
Common cash dividends declared ($1.23 per share)
 (76.2) (76.2)
Balance at September 30, 2021$943.6 $1,026.9 $14.3 $1,984.8 
Balance at December 31, 2019$1,049.3 $953.6 $11.0 $2,013.9 
Cumulative change related to the adoption of ASU 2016-13 (24.1) (24.1)
Adjusted balance at January 1, 20201,049.3 929.5 11.0 1,989.8 
Net income 114.3  114.3 
Other comprehensive income, net of tax expense  50.9 50.9 
Common stock transactions:
2,539,041 common shares purchased and retired
(78.9)  (78.9)
19,491 common shares issued
    
329,024 non-vested common shares issued
    
30,323 non-vested common shares forfeited or canceled
    
89,411 stock options exercised, net of 26,124 shares tendered in payment of option price and income tax withholding amounts
0.8   0.8 
Stock-based compensation expense