FIRST INTERSTATE BANCSYSTEM INC (FIBK) Business

Item 1. Business

Our Company

We are a financial and bank holding company focused on community banking. Since our incorporation in Montana in 1971, we have grown both organically and through strategic acquisitions. As of February 20, 2026, we operated 290 banking offices, including branches and detached drive-up facilities, in communities across 12 states— Colorado, Idaho, Iowa, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington, and Wyoming. Through our bank subsidiary, First Interstate Bank, we deliver a comprehensive range of banking products and services—including online and mobile banking—to individuals, businesses, government entities, and others throughout our market areas.

We are proud to provide financial services and products to clients that participate in a wide variety of industries, including:

Our common stock is traded on the NASDAQ Global Select Market, or NASDAQ, under the symbol “FIBK.” Since our initial public offering, we have expanded our market reach through organic growth and strategic acquisitions, including our acquisitions of Mountain West Bank, United Bank, N.A., Flathead Bank of Bigfork, Bank of the Cascades, Inland Northwest Bank, Idaho Independent Bank, Community 1st Bank, and Great Western Bank. Our current strategy emphasizes disciplined organic growth by deepening and expanding full client relationships across deposits, lending and fee-based services. As of December 31, 2025, we had consolidated assets of $26.6 billion, deposits of $22.1 billion, loans held for investment of $15.2 billion, and total stockholders’ equity of $3.4 billion.

Our vision is to meet people where they are and help them reach where they want to be. Rooted in the principles of community banking, we build lasting relationships and make thoughtful decisions that serve our employees, clients, communities and shareholders.

Our long-term philosophy emphasizes providing high-quality financial products and services, delivering exceptional client service, influencing business leadership within our communities through professional and dedicated bankers, supporting our communities through financial contributions and socially responsible leadership, and cultivating a strong corporate culture.

Building on this foundation, we are executing a strategic plan intended to refocus capital investment, optimize our balance sheet and improve core profitability, while continuing to advance our business in a disciplined and prudent manner. This plan includes initiatives to enhance credit processes and risk culture, optimize our footprint and branch network, and emphasize disciplined, relationship-driven organic growth in our existing market areas. In furtherance of our strategic plan focused on organic growth and relationship banking, we are prioritizing investment into existing market areas where we have brand density and are well positioned to serve the needs of our customers. Accordingly, we are undertaking a comprehensive review of our branch network to optimize our physical footprint, including exiting markets that are not aligned with our strategic plan and reallocating capital, talent and resources to expand in markets where we have meaningful market share and attractive growth prospects. For example, in October 2025, we completed the divestiture of our banking operations in Arizona and Kansas and also announced the contemplated sale of 11 branches in Nebraska, which transaction is expected to close at the beginning of the second quarter of 2026. We opened one branch in Montana on February 2, 2026 and intend to close four branches in eastern Nebraska, one in Minnesota, and one in North Dakota at the end of February 2026.

We have further aligned select products and activities with our strategic plan, emphasizing relationship-based business and disciplined underwriting consistent with long-term performance. In 2025, we took deliberate actions to reduce or exit selected exposures, including the intentional runoff of certain non-relationship and transactional credits and the discontinuation or outsourcing of lending products. For example, we exited our indirect lending origination business in early 2025 and outsourced our consumer credit card portfolio in mid-2025, as further described in Part II, Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations.”

In addition, during the fourth quarter of 2025, we initiated a transformation of our banking organization, changing from a layered, regional and market structure to a flatter model. The redesign includes new State Presidents at the Bank, a majority of whom are from within the Bank, supplemented by select external hires, and a more streamlined chain of responsibility designed to speed up local decision-making and align the decision framework with our relationship-driven organic growth strategy. We expect this redesign to be nearly complete in the first quarter of 2026.

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Community Banking

We have one operating segment—community banking. The Company’s chief operating decision maker is its Chief Executive Officer who is charged with management of the Company and is responsible for the evaluation of operating performance and decision making about the allocation of resources to the operating segment. Community banking encompasses commercial, governmental, and consumer banking services provided through our Bank, which primarily include the acceptance of deposits, the extension of credit, mortgage loan origination and servicing, and wealth management, which includes trust, employee benefit, investment management, insurance, agency, and custodial services to individuals, businesses, and nonprofit organizations. Our philosophy emphasizes a local focus through a personalized service approach while also strengthening the communities in our market areas through community involvement, service activities, and philanthropy. We grant our banking offices significant authority in delivering products in response to local market considerations and client needs. This autonomy enables our banking offices to remain competitive by quickly responding to local market conditions and enhancing relationships with our clients in those markets. While our banking offices enjoy a level of flexibility, they remain accountable to company-wide standards and established limits on their authority and discretion. This combination of authority and accountability allows our banking offices to provide personalized service and localized community support while at the same time remaining focused on our overall financial vitality.

Lending Activities

We offer real estate, consumer, commercial, agricultural, and other loans to individuals, government entities, and businesses in our market areas. We have comprehensive credit policies that establish company-wide underwriting and documentation standards to manage the lending process and limit our risk. Each loan must meet minimum underwriting standards specified in our credit policies and procedures, with certain exceptions to those policies, which generally specify that loans:

(1)are made to borrowers who are generally located within or adjacent to our market footprint or own businesses and/or real estate within or adjacent to our footprint, with limited exceptions that may include participation loans and loans to national accounts;

(2)are made only for identified legal purposes;

(3)have specifically identified sources of repayment;

(4)mature within designated maximum maturity periods that coincide with repayment sources;

(5)are appropriately collateralized whenever possible;

(6)are supported by current credit information;

(7)do not exceed the Bank’s legal lending limit;

(8)include medium-term fixed interest rates or variable rates that are adjusted within designated time frames; and

(9)require compliance with laws and regulations including a flood zone and risk determination prior to closing.

In addition, our credit policies include lending limitations to minimize undue (or excessive) concentrations of credit in agricultural, commercial, real estate, or consumer loans. Furthermore, the criteria meeting our underwriting standards must be documented, with exceptions noted, as a part of the loan approval process.

While each loan must meet minimum underwriting standards, qualified bankers are granted levels of credit authority for approving and pricing loans to assure that banking offices are responsive to competitive issues and community needs in each market area. Credit authorization is established by individual role and assigned based on the credit experience, credit acumen and performance of each banker. Credit authorization is granted under the direction of our Chief Credit Officer and is reviewed on an ongoing basis. Loan requests over the authority of our bankers are approved by designated Credit Officers and, if necessary, by our new credit committee as further discussed below.

In 2025, we completed a comprehensive internal review and assessment of our credit risk management framework and credit policies that was initiated in late 2024. Among other things, we implemented a new credit review and approval process under which new and renewed loans and commitments above defined exposure thresholds are reviewed by a centralized credit committee comprised of senior credit and executive leadership. This committee-based process is designed to promote consistent application of our credit policies and enhance our risk culture for higher-exposure relationships, while still maintaining efficient approval procedures to ensure timely speed to market.

In addition, during 2025 we conducted a comprehensive review of our largest loan exposures, including detailed borrower-level assessments of these relationships. As part of this review, we enhanced our ongoing monitoring and action plans for higher-exposure relationships, including certain larger criticized credits, and pursued targeted paydowns and payoffs where appropriate. We believe these proactive steps, together with our disciplined underwriting standards on new production, position us well to continue supporting stable asset quality over time and in various economic scenarios.

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Deposit Products

We offer traditional depository products including checking, savings, and time deposits. Deposits at the Bank are insured by the Federal Deposit Insurance Corporation, or the FDIC, up to statutory limits. We also offer repurchase agreements primarily to commercial and municipal depositors. Under repurchase agreements, we sell investment securities held by the Bank to our clients under an agreement to repurchase the investment securities at a specified time or on demand. All outstanding repurchase agreements are due in one business day. Additionally, the Company is a member of the IntraFi Network, which enables us to offer our customers insurance coverage on interest-bearing demand, money market and certificate of deposit balances in excess of the FDIC insurance coverage limits.

Wealth Management

We provide a wide range of trust, employee benefit, investment management, insurance, agency, and custodial services to individuals, businesses, and nonprofit organizations. These services include the administration of estates and personal trusts, management of investment accounts for individuals, employee benefit plans and charitable foundations, and insurance planning.

Centralized Services

We have centralized certain operational activities to provide consistent service levels to our clients across the Bank, which helps us gain efficiency in management of those activities as well as ensure regulatory compliance. Centralized operational activities generally support our banking offices in the delivery of products and services to clients and include:

•marketing;

•credit review;

•loan servicing;

•credit card servicing;

•mortgage loan sales and servicing;

•loan collections; and

•other operational activities.

To reduce operating costs and capitalize on the technical capabilities of selected vendors, we also leverage third-party service providers to selectively outsource certain bank operations and services, such as certain data processing, loan servicing, credit card issuance, and deposit processing systems.

Additionally, specialized staff support services have been centralized to enable our branches to more efficiently serve their markets. These services include:

•credit risk management;

•finance;

•human resource management;

•internal audit;

•facilities management;

•technology;

•risk management;

•legal;

•compliance; and

•other support services.

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Market Area

The following table reflects our deposit market share and branch locations by state:

(1) Source: FDIC.gov-data as of June 30, 2025.

(2) As of December 31, 2025.

(3) The branches in Fargo, North Dakota and Marshall, Minnesota are expected to close at the end of February 2026.

(4) One branch in Billings, Montana opened in February 2026.

(5) Four Nebraska branches are expected to close at the end of February 2026. Eleven Nebraska branches are under agreement to be sold to Security First Bank, which transaction is currently anticipated to close at the beginning of the second quarter of 2026. The Company will have 29 branches remaining in Nebraska after completion of the pending sale and closures.

We operate in markets with a diverse employment base covering numerous industries and we believe our community bank approach to providing client service is a competitive advantage that strengthens the Company’s ability to effectively provide financial products and services to businesses and individuals in its markets.

Competition

There is significant competition among commercial banks in our market areas. We also compete with other providers of financial services that actively engage in providing various types of loans and other financial services to their clients, such as:

•savings and loan associations;

•credit unions;

•financial technology companies;

•internet banks;

•consumer finance companies;

•brokerage firms;

•mortgage banking companies;

•insurance companies;

•securities firms;

•mutual funds;

•government agencies; and

•major retailers.

To remain competitive in this congested industry, we continue to develop our omni-channel experience across our website, social media, and email, in addition to our offline channels, such as brick and mortar banking offices. Some of our competitors have greater resources and, as such, may have higher lending limits and may offer other services that we do not provide. We generally compete on the basis of service and responsiveness to client needs, available loan and deposit products, rates of interest charged on loans, rates of interest paid for deposits, and the availability and pricing of services such as trust, employee benefit, investment, and insurance services.

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Government Regulation and Supervision

We are subject to extensive government regulation and supervision under federal and state laws. Summaries of the material laws and regulations that are applicable to us are provided below. The descriptions that follow are not intended to summarize all laws and regulations applicable to us. Furthermore, the descriptions that follow do not purport to be complete and are qualified in their entirety by reference to the full provisions of those laws and regulations. In addition to laws and regulations, state and federal banking regulatory agencies may issue policy statements, interpretive letters, and similar written guidance that may impose additional regulatory obligations or otherwise affect the conduct of our business. Additionally, proposals to change laws and regulations are frequently introduced at both the federal and state levels. The likelihood and timing of any such changes and their impact on the Company cannot be determined with certainty.

Regulatory Authorities

As a public company with our securities listed for trading on the NASDAQ, we are subject to the disclosure and regulatory requirements of the Securities and Exchange Commission, or SEC, including under the Securities Act, the Exchange Act, and the rules and listing standards of the NASDAQ.

As a financial and bank holding company, we are subject to regulation under the Bank Holding Company Act of 1956, as amended, and to supervision, regulation, and regular examination by the Board of Governors of the Federal Reserve System (the “Federal Reserve”).

The Bank is subject to supervision and regular examination by its primary banking regulators, the Federal Reserve and the Montana Department of Administration, Division of Banking and Financial Institutions (the “Montana Division”). The Bank is also subject to supervision and examination by the Consumer Financial Protection Bureau (“CFPB”).

The Bank’s deposits are insured by the Deposit Insurance Fund (“DIF”) administered by the FDIC in the manner and to the extent provided by law. As such, the Bank is subject to the Federal Deposit Insurance Act (the “FDIA”) and FDIC regulations relating to deposit insurance and may also be subject to supervision and examination by the FDIC.

We are currently subject to the regulatory capital framework and guidelines reached by Basel III as adopted by the Federal Reserve. The Federal Reserve has risk-based capital adequacy guidelines intended to measure capital adequacy with regard to a banking organization’s balance sheet, including off-balance sheet exposures such as unused portions of loan commitments, letters of credit, and recourse arrangements.

The extensive regulation of the Bank limits both the activities in which the Bank may engage and the conduct of its permitted activities. Further, the laws and regulations impose reporting and information collection obligations on the Bank. The Bank incurs significant costs relating to compliance with various laws and regulations and the collection and retention of information. As the regulatory framework for bank holding companies and banks continues to evolve and become more complex, the cost of complying with regulatory requirements continues to increase.

Financial and Bank Holding Company

First Interstate is a bank holding company and has registered as a financial holding company under regulations issued by the Federal Reserve. As a financial holding company, we may engage in business activities that are determined by the Federal Reserve to be financial in nature or incidental to financial activities as well as all activities authorized generally to bank holding companies. We may continue to engage in authorized financial activities provided that we remain a financial holding company and are “well-capitalized” and “well-managed.” We do not currently engage in significant financial holding company business or activities not otherwise permitted generally for bank holding companies.

Under federal law, First Interstate is required to serve as a source of financial and managerial strength to the Bank, which may include providing financial assistance to the Bank if the Bank experiences financial distress. Under existing Federal Reserve source of strength policies, the Federal Reserve may require a bank holding company to make capital injections into a troubled subsidiary bank. The Federal Reserve may also determine that the bank holding company is engaging in unsafe and unsound practices if it fails to commit resources to a subsidiary bank.

We are required by the Bank Holding Company Act to obtain Federal Reserve approval prior to acquiring, directly or indirectly, ownership or control of voting shares of any bank, if, after such acquisition, we would own or control more than 5% of its voting stock. The Federal Reserve considers a number of factors in evaluating acquisitions, including the financial and managerial resources and future prospects of the parties, the convenience and needs of the communities served, and competitive factors. Under the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd-Frank Act”), when considering an application, the Federal Reserve is also required to evaluate whether the transaction would result in more concentrated risks to the United States banking or financial system. Under federal law and regulations, a bank holding company may acquire banks in states other than its home state if, among other things, the bank holding company is both “well-capitalized” and “well-managed” both before and after the acquisition.

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Banks may also merge across state lines. With additional changes made to federal statutes under the Dodd-Frank Act, banks are also permitted to establish new interstate branches if a bank located in the target state could establish a new branch at the proposed location without regard to state laws limiting interstate de novo branching. A state can prohibit interstate mergers entirely or prohibit them if the continuing bank would control insured bank deposits in excess of a specified percentage of total insured bank deposits in the state. Under Montana law, a bank cannot acquire control of a bank located in Montana if, after the acquisition, the acquiring institution would control, in the aggregate, more than 30% of the total deposits of insured depository institutions located in Montana. As of June 30, 2025, based on publicly available information provided by the FDIC, we believe the Bank controlled approximately 16.6% of the total deposits of all insured depository institutions located in Montana. As such, the state limitation may limit our ability to directly or indirectly acquire additional banks located in Montana.

In order to assess the financial strength of the bank holding company, the Federal Reserve and the State of Montana may conduct periodic on-site and off-site inspections and credit reviews throughout the year. The federal banking agencies, including the Federal Reserve, may require additional information and reports from us. In addition, the Federal Reserve may examine, and require reports and information regarding, any entity that we control, including entities other than banks or entities engaged in financial activities. In certain circumstances, the Federal Reserve may require us to divest of non-bank entities or limit the activities of those entities even if the activities are otherwise permitted for bank holding companies under governing law.

Dividends and Restrictions on Transfers of Funds

Dividends from the Bank are the primary source of funds for the payment of our operating expenses and for the payment of dividends to our shareholders. Dividends are also limited by state and federal laws and regulations. We are also subject to various regulatory restrictions relating to capital distributions, including dividends, regulatory capital minimums, and the requirement to remain “well-capitalized” under the prompt corrective action regulations summarized below under the caption “Business – Government Regulation and Supervision – Capital Standards and Prompt Corrective Action.” In general, the Bank is limited to paying dividends that do not exceed the current year net profits together with retained earnings from the two preceding calendar years unless prior consent of the Federal Reserve is obtained. In addition, the Bank may not pay dividends in excess of the previous two years’ net earnings without providing notice to the Montana Division.

The capital buffer rules adopted by the federal banking regulators in accordance with the Basel Accords impose further limitations on the Bank’s ability to pay dividends. In general, the Bank’s ability to pay dividends is limited under the capital buffer rules unless the Bank’s common equity conservation buffer exceeds the minimum required capital ratio by 2.5% of risk-weighted assets.

A state or federal banking regulator may also impose, by regulatory order or agreement of the Bank, specific dividend limitations or prohibitions. The Bank is not, however, currently subject to a specific regulatory dividend limitation.

The Federal Reserve has issued a policy statement regarding the payment of dividends and the repurchase of common stock by bank holding companies. In general, the policy provides that dividends should be paid only out of current earnings and only if the prospective rate of earnings retention by the holding company appears consistent with the organization’s capital needs, asset quality, and overall financial condition. Regulatory guidance provides for prior regulatory consultation with respect to capital distributions in certain circumstances such as where the company’s net income for the past four quarters (net of previous capital distributions) is insufficient to fully fund the dividend or the company’s overall rate of earnings retention is inconsistent with the company’s capital needs and overall financial condition. The ability of a holding company to pay dividends may be restricted if a subsidiary bank becomes under-capitalized. The policy statement also states that a holding company should inform the Federal Reserve supervisory staff prior to redeeming or repurchasing common stock or perpetual preferred stock if the holding company is experiencing financial weaknesses or if the repurchase or redemption would result in a net reduction, as of the end of a quarter, in the amount of such equity instruments outstanding compared with the beginning of the quarter in which the redemption or repurchase occurred. These regulatory policies may affect our ability to pay dividends, repurchase shares of common stock, or otherwise engage in capital distributions. The Bank remains compliant with these policies and requirements.

Capital Standards and Prompt Corrective Action

Banks and bank holding companies are subject to various regulatory capital requirements administered by state and federal banking agencies, which involve quantitative measures of assets, liabilities, and certain off-balance sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgments by regulators about components, risk weighting, and other factors. The capital requirements are intended to ensure that banking organizations have adequate capital given the risk levels of assets and off-balance sheet financial instruments and are applied separately to the Bank and its parent holding company.

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Federal regulations require FDIC-insured depository institutions and bank holding companies to meet several minimum capital standards:

•a common equity Tier 1 capital to risk-based assets ratio of 4.5%;

•a Tier 1 capital to risk-based assets ratio of 6.0%;

•a total capital to risk-based assets ratio of 8.0%; and

•a 4.0% Tier 1 capital to total assets leverage ratio.

The existing capital requirements were effective January 1, 2015, and are based on recommendations of the Basel Committee on Banking Supervision and requirements of the Dodd-Frank Act.

For purposes of the regulatory capital requirements, common equity Tier 1 capital is generally defined as common stockholders’ equity and retained earnings and is reduced by substantially all of the regulatory deductions including items such as goodwill and other intangibles and certain deferred tax assets. Tier 1 capital is generally defined as common equity Tier 1 capital and additional Tier 1 capital. Additional Tier 1 capital includes certain noncumulative perpetual preferred stock and related surplus and minority interests in equity accounts of consolidated subsidiaries. Total capital includes Tier 1 capital (common equity Tier 1 capital plus additional Tier 1 capital) and Tier 2 capital. Tier 2 capital is composed of capital instruments and related surplus, meeting specified requirements, and may include cumulative preferred stock and long-term perpetual preferred stock, mandatory convertible securities, intermediate preferred stock, and subordinated debt. Also included in Tier 2 capital is the allowance for credit losses limited to a maximum of 1.25% of risk-weighted assets and, for institutions like us that have exercised an opt-out election regarding the treatment of Accumulated Other Comprehensive Income (“AOCI”), up to 45.0% of net unrealized gains on available-for-sale equity securities with readily determinable fair market values. Institutions that have not exercised the AOCI opt-out have AOCI incorporated into common equity Tier 1 capital (including unrealized gains and losses on available-for-sale-securities). Calculation of all types of regulatory capital is subject to deductions and adjustments specified in the regulations.

In determining the amount of risk-weighted assets for purposes of calculating risk-based capital ratios, all assets, including certain off-balance sheet assets (for example, recourse obligations, direct credit substitutes, residual interests), are multiplied by a risk weight factor assigned by the regulations based on the risks believed inherent in the type of asset.

Higher levels of capital are required for asset categories believed to present greater risk. For example, a risk weight of 0% is assigned to cash and United States government securities, a risk weight of 50% generally is assigned to prudently underwritten first lien one- to four-family residential mortgages, a risk weight of 100% is assigned to commercial and consumer loans, a risk weight of 150% is assigned to certain past due loans, and a risk weight of between 0% to 600% is assigned to permissible equity interests, depending on certain specified factors.

In addition to establishing the minimum regulatory capital requirements, the regulations limit capital distributions and certain discretionary bonus payments to management if the institution does not hold a “capital conservation buffer” consisting of 2.5% of common equity Tier 1 capital to risk-weighted assets above the amount necessary to meet its minimum risk-based capital requirements. In assessing an institution’s capital adequacy, the Federal Reserve takes into consideration not only these numeric factors, but qualitative factors as well and has the authority to establish higher capital requirements in individual cases where deemed necessary. The Federal Reserve has not established individual capital requirements applicable to us.

Federal law requires the federal banking agencies to take “prompt corrective action” in respect of depository institutions that do not meet minimum capital requirements. The law sets forth the following five capital tiers:

•“well capitalized;”

•“adequately capitalized;”

•“under-capitalized;”

•“significantly under-capitalized;” and

•“critically under-capitalized.”

A depository institution’s capital tier will depend upon how its capital levels compare with various relevant capital measures and certain other factors, as established by regulation. The relevant capital measures are the common equity tier 1 capital ratio, total capital ratio, the tier 1 capital ratio, and the leverage ratio.

A depository institution is generally prohibited from making any capital distributions (including payment of a dividend) or paying any management fee to its parent holding company if the depository institution would thereafter be under-capitalized. Under-capitalized institutions may be subject to growth limitations and other restrictions and are required to submit a capital restoration plan. If a depository institution fails to submit an acceptable plan, it is treated as if it is “significantly under-capitalized.”

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“Significantly under-capitalized” depository institutions are subject to additional requirements and restrictions, such as orders to sell sufficient stock to become “adequately capitalized,” to reduce total assets, restrict interest rates paid, remove management and directors, and cease receipt of deposits from correspondent banks. “Critically under-capitalized” institutions are subject to the appointment of a receiver or conservator.

The capital stock of banks organized under Montana law, such as the Bank, may be subject to assessment upon the direction of the Montana Department of Administration under the Montana Bank Act. Under the Montana Bank Act, if the Department of Administration determines an impairment of a bank’s capital exists, it may notify the Bank’s Board of the impairment and require payment of an assessment on the bank stock. If the bank fails to do so, the Department of Administration may, among other things, take charge of the bank and proceed to liquidate the bank.

Restrictions on Transactions with Affiliates, Directors, and Officers

Under the Federal Reserve Act, the Bank may not lend funds or otherwise extend credit to its parent holding company or any other affiliate, except on specified types and amounts of collateral generally upon market terms and conditions. The Federal Reserve also has authority to define and limit the transactions between banks and their affiliates. The Federal Reserve’s Regulation W and relevant federal statutes and regulations, among other authorities, impose significant limitations on transactions in which the Bank may engage with us or with other affiliates, including per-affiliate and aggregate limits on affiliate transactions.

Federal Reserve Regulation O restricts loans to the Bank’s and its parent holding company’s insiders, which includes directors, certain officers, and principal shareholders and their respective related interests. All extensions of credit to the insiders and their related interests must be on the same terms as, and subject to the same loan underwriting requirements as, loans to persons who are not insiders. In addition, Regulation O imposes lending limits on loans to insiders and their related interests and imposes, in certain circumstances, requirements for prior approval of the loans by the Bank Board.

Safety and Soundness Standards and Other Supervisory and Enforcement Mechanisms

The federal banking agencies have adopted guidelines establishing standards for safety and soundness, asset quality and earnings, loan documentation, credit underwriting, interest rate risk exposure, internal controls, and audit systems. These standards are designed to identify potential concerns and ensure action is taken to address those concerns before they pose a risk to the DIF. If a federal banking agency determines that an institution fails to meet any of these standards, the agency may require the institution to submit an acceptable plan to achieve compliance with the standard. If the institution fails to submit an acceptable plan within the time allowed by the agency or fails in any material respect to implement an accepted plan, the agency must, by order, require the institution to correct the deficiency and may take other supervisory action.

Pursuant to the Dodd-Frank Act, federal banking regulators impose additional supervisory measures on banking organizations such as us when they exceed $10 billion in assets. These include enhanced risk management and corporate governance processes specified by the regulators.

The Federal Reserve has authority to bring an enforcement action against a bank or bank holding company and all “institution-affiliated parties” of a bank or bank holding company, including directors, officers, stockholders, and under certain circumstances, attorneys, appraisers, and accountants for the bank or holding company. Formal enforcement actions may include measures such as the issuance of a capital directive or cease and desist order for the removal of officers and/or directors or the appointment of a receiver or conservator. Civil money penalties cover a wide range of violations and actions, and can range up to $5,000 per day, unless a finding of knowing or reckless disregard is made, in which case penalties may be as high as $1 million per day. The FDIC also has the authority to terminate deposit insurance or recommend to the Federal Reserve that enforcement action be taken with respect to a particular bank. If such action is not taken, the FDIC has authority to take the action under specified circumstances. Montana law also provides the Montana Division with various enforcement mechanisms and, ultimately, authority to appoint a receiver or conservator for a Montana bank.

Deposit Insurance

The FDIC insures our client deposits through the DIF up to $250,000 per depositor. The amount of FDIC assessments paid by each DIF member institution is based on financial measures and supervisory ratings derived from a statistical model estimating the probability of failure within a three-year period, with banks deemed more risky paying higher assessments.

The FDIC was required by the Dodd-Frank Act to take actions necessary to cause the DIF to reach a reserve ratio of 1.35% of total estimated insured deposits by September 30, 2020. As of September 30, 2020, the FDIC had announced that the ratio was 1.30% due largely to consequences of the COVID-19 pandemic. The FDIC adopted a plan to restore the fund to the 1.35% ratio within eight years, but did not change its assessment schedule. On October 18, 2022, the FDIC finalized a rule that would increase initial base deposit insurance assessment rates by two basis points, beginning with the first quarterly assessment period of 2023 and in 2024 and 2025 the FDIC Board maintained the designated reserve ratio for the DIF at two basis points for 2025 and 2026, respectively.

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In addition, to recover costs associated with protecting uninsured depositors during the bank failures in the first half of 2023, in November 2023, the FDIC implemented a 13.4 basis point annual special assessment on uninsured deposits above $5 billion, to be collected during eight consecutive quarters beginning with the first quarter of 2024. The Company accrued $10.5 million in the fourth quarter of 2023 and an additional $1.5 million in the first quarter of 2024 for the special assessment. The special assessment is in addition to the assessment rates finalized as part of FDIC’s Amended Restoration Plan. In an update provided on December 16, 2025, the FDIC staff projects that the reserve ratio is on track to exceed the initial estimate ahead of the statutory deadline of September 30, 2028 and reduced the special assessment rate for the eighth collection quarter from 3.36 basis points to 2.97 basis points. This is intended to allow the FDIC to recover approximately the full amount of estimated losses as of September 30, 2025, while minimizing any amounts collected in excess of the estimated losses.

All FDIC-insured institutions are also required to pay assessments to the FDIC to fund interest payments on bonds issued by the Financing Corporation, or the FICO, an agency of the Federal government established to recapitalize the predecessor to the DIF. The assessment rate is applied to total average assets less tangible equity, as defined under the Dodd-Frank Act. The assessment rate schedule can change from time-to-time at the discretion of the FDIC, subject to certain limits. Under the current system, premiums are assessed quarterly.

Interchange Fees

Under the Durbin Amendment to the Dodd-Frank Act, also known as Regulation II, the Federal Reserve adopted rules establishing standards for assessing whether the interchange fees that may be charged with respect to certain electronic debit transactions are “reasonable and proportional” to the costs incurred by issuers for processing such transactions, which alters the competitive structure of the debit card payment processing industry and caps debit card interchange fees for banks with over $10 billion in assets. Interchange fees are charges that merchants pay to us and other card-issuing banks for processing electronic payment transactions. The Federal Reserve also has rules governing routing and exclusivity that require issuers to offer two unaffiliated networks for routing transactions on each debit or prepaid product.

On October 3, 2022, the Federal Reserve finalized a rule that amends Regulation II to specify, among other things, that debit card issuers should enable all debit card transactions, including card-not-present transactions such as online payments, to be processed on at least two unaffiliated payment card networks. The final rule became effective July 1, 2023. In October 2023, the Federal Reserve proposed revising Regulation II to lower the cap from its current rate of 21 cents and 0.05% of the transaction, plus a one-cent fraud-prevention adjustment, to 14.4 cents and 0.04% per transaction and a 1.3 cents fraud-prevention adjustment, which originally was to take effect on June 30, 2025. Due to active litigation involving the rule, it is not clear whether the Federal Reserve will finalize the October 2023 proposed rulemaking, and how, if at all, the Federal Reserve will enforce the rule. We are subject to the interchange fee cap and having at least two unaffiliated payment card networks because our assets exceed $10 billion.

Client Privacy and Other Consumer Protections

Federal and State laws impose client privacy requirements on any company engaged in financial activities, including us. Under these requirements, a financial company is required to protect the security and confidentiality of clients’ nonpublic personal information. In addition, for clients who obtain a financial product such as a loan for personal, family, or household purposes, a financial holding company is required to disclose its privacy policy to the client at the time the relationship is established and annually thereafter. The financial company must also disclose its policies concerning the sharing of the client’s nonpublic personal information with affiliates and third parties. Finally, a financial company is prohibited from disclosing an account number or similar item to a third party for use in telemarketing, direct mail marketing, or marketing through electronic mail.

The Bank is subject to a variety of federal and state laws, regulations, and reporting obligations aimed at protecting consumers and Bank clients. Failure to comply with these laws and regulations may, among other things, impair the collection of loans made in violation of the laws and regulations, provide borrowers or other clients certain rights and remedies, or result in the imposition of penalties on the Bank. Certain of these laws and regulations are described below.

The Equal Credit Opportunity Act generally prohibits discrimination in credit transactions on, among other things, the basis of race, color, religion, national origin, sex, marital status, or age and, in certain circumstances, limits the Bank’s ability to require co-obligors or guarantors as a condition of the extension of credit to an individual.

The Real Estate Settlement Procedures Act (“RESPA”) requires certain disclosures be provided to borrowers in real estate loan closings or other real estate settlements. In addition, RESPA limits or prohibits certain settlement practices, fee sharing, “kickbacks,” and similar practices that are considered to be abusive.

The Truth in Lending Act (“TILA”) requires disclosures to borrowers and other parties in consumer loans, including, among other things, disclosures relating to interest rates and other finance charges, payments and payment schedules, and annual percentage rates.

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The Fair Housing Act regulates, among other things, lending practices in residential housing and prohibits discrimination in housing-related lending activities on the basis of race, color, religion, national origin, sex, handicap, disability, or familial status.

The Home Mortgage Disclosure Act requires certain lenders and other firms engaged in the home mortgage industry to collect and report information relating to applicants, borrowers, and home mortgage lending activities in which they engage in their market areas or communities. The information is used for, among other purposes, evaluation of discrimination or other impermissible acts in home mortgage lending.

The Home Ownership and Equity Protection Act regulates terms and disclosures of certain closed-end home mortgage loans that are not purchase money loans and includes loans classified as “high-cost loans.”

The Fair Credit Reporting Act, as amended by the Fair and Accurate Credit Transactions Act, generally limits lenders and other financial firms in their collection, use, or dissemination of client credit information, gives clients some access to, and control over, their credit information, and requires financial firms to establish policies and procedures intended to deter identity theft and related frauds.

The Fair Debt Collection Practices Act regulates actions that may be taken in the collection of consumer debts and provides consumers with certain rights of access to information related to collection actions.

The Electronic Fund Transfer Act regulates fees and other terms on electronic funds transactions.

The Dodd-Frank Wall Street Reform and Consumer Protection Act prohibits, among other things, lending practices to consumers that are unfair, deceptive, or abusive.

The CFPB has promulgated numerous regulations relating to consumer financial services-related topics, such as mortgage origination disclosures, mortgage servicing practices, and others. In addition, the CFPB continues to issue and reconsider significant regulations affecting consumer financial products and data access (including rules implementing Sections 1033 and 1071 of the Dodd-Frank Act), and certain of these rulemakings and compliance timelines have been subject to litigation, stays, or extensions, which may create uncertainty regarding the scope and timing of our compliance obligations and could require additional operational, technology, and compliance investments.

The CRA generally requires the federal banking agencies to evaluate the record of a financial institution in meeting the credit needs of its local communities, including low- and moderate-income neighborhoods. In addition to substantial penalties and corrective measures that may be assessed for a violation of fair lending laws, the federal banking agencies may take compliance with such laws and the CRA into account when evaluating applications for transactions such as mergers and for new branches. Federal banking agencies issued a final rule in October 2023 intended to modernize the CRA implementing regulations; however, the rule has been subject to litigation and has not taken effect and the agencies have proposed to rescind and replace it, and accordingly the applicable CRA regulatory framework and implementation timeline remain uncertain, which could increase our compliance costs and could affect our CRA ratings and our ability to open branches, complete acquisitions, or undertake other strategic transactions. In July 2025, the federal banking agencies issued a proposal to rescind the 2023 CRA rulemaking in favor of returning to a standard largely similar to the rules that were in effect in 1995. To date, the agencies have not issued a final rulemaking to implement the July 2025 proposal.

In connection with its assessment of CRA performance, the appropriate bank regulatory agency assigns a rating of “outstanding,” “satisfactory,” “needs to improve,” or “substantial noncompliance.” The Bank received a “satisfactory” rating on its most recently published CRA examination. Although the Bank’s policies and procedures are designed to achieve compliance with all fair lending and CRA requirements, instances of non-compliance are occasionally identified through normal operational activities. Management endeavors to respond proactively to any instances of non-compliance and to implement and update appropriate procedures to prevent instances of non-compliance and other violations from occurring.

USA PATRIOT Act

The USA PATRIOT Act of 2001 amended the Bank Secrecy Act of 1970 and the Money Laundering Control Act of 1986 and adopted additional measures requiring insured depository institutions, broker-dealers, and certain other financial institutions to have policies, procedures, and controls to detect, prevent, and report money laundering and terrorist financing. The laws and related regulations also provide for information sharing, subject to conditions, between federal law enforcement agencies and financial institutions, as well as among financial institutions, for counter-terrorism purposes. Federal banking regulators are required, when reviewing bank holding company acquisition or merger applications, to take into account the effectiveness of the anti-money laundering activities of the applicants.

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Office of Foreign Asset Control

The United States Treasury Office of Foreign Asset Control enforces economic and trade sanctions imposed by the United States on foreign persons and governments. Among other authorities, the Office of Foreign Asset Control, or OFAC, may require United States financial institutions to block or “freeze” assets of identified foreign persons or governments which come within the control of the financial institution. Financial institutions are required to adopt procedures for identification of new and existing deposit accounts and other relationships with persons or governments identified by OFAC and to timely report the accounts or relationships to OFAC.

Incentive Compensation

In May 2016, the Federal Reserve Board, other federal banking agencies, and the SEC jointly published a re-proposed rule-making designed to implement provisions of the Dodd-Frank Act prohibiting incentive compensation arrangements that would encourage inappropriate risk taking at a covered institution, which includes a bank or bank holding company with $1 billion or more of assets, such as us. The proposed rule (i) prohibits incentive-based compensation arrangements that encourage executive officers, employees, directors, or principal shareholders to expose the institution to inappropriate risks by providing excessive compensation (based on the standards for excessive compensation adopted pursuant to the FDIA) and (ii) prohibits incentive-based compensation arrangements for executive officers, employees, directors or principal shareholders that could lead to a material financial loss for the institution. The proposed rule requires covered institutions to establish policies and procedures for monitoring and evaluating their compensation practices. The comment period ended in July 2016 and a notice of proposed rulemaking was released in May 2024. Although final rules had not been adopted as of December 31, 2025, if these or other regulations are adopted in a form similar to the proposed rule-making, they could impose limitations on the manner in which we may structure compensation for our executives.

Cybersecurity

Federal regulators have issued two related statements regarding cybersecurity. One statement indicates that financial institutions should design multiple layers of security controls to establish lines of defense and ensure their risk management processes also address the risk posed by compromised client credentials, including security measures to reliably authenticate clients accessing internet-based services of the financial institution. The other statement indicates that a financial institution’s management is expected to maintain sufficient business continuity planning processes to ensure the rapid recovery, resumption, and maintenance of the institution’s operations after a cyber-attack involving destructive malware. A financial institution is also expected to develop appropriate processes to enable recovery of data and business operations and address rebuilding network capabilities and restoring data if the institution or its critical service providers fall victim to this type of cyber-attack. If we fail to observe the regulatory guidance, we could be subject to various regulatory sanctions, including financial penalties.

For additional discussion on cybersecurity, see Part I, Item 1C, “Cybersecurity” included herein.

Recent Executive Orders

Banking regulation and supervisory priorities may shift in response to political developments, including executive actions and changes in regulatory leadership. In 2025, federal actions affecting the financial services industry included changes relating to the use of “reputational risk” in supervision and the application of disparate-impact liability in connection with certain federal civil rights and fair lending laws. For example, on August 7, 2025, the President issued an executive order titled “Guaranteeing Fair Banking for All Americans,” which directs federal banking regulators, to the extent permitted by law, to remove the use of reputational risk or similar concepts from guidance documents, manuals and other materials within 180 days of the order. In addition, on April 23, 2025, the President issued an executive order titled “Restoring Equality of Opportunity and Meritocracy,” which directs federal agencies to deprioritize enforcement of statutes and regulations to the extent they include disparate-impact liability and to review certain pending matters under federal civil rights laws, including the Equal Credit Opportunity Act and the Fair Housing Act. The Bank continues to monitor these and other regulatory developments and remains committed to providing fair and competitive banking products and services in compliance with applicable laws and regulations.

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Human Capital

Culture is critically important to the Company’s success; our people are our number one priority. We approach our culture with an aspirational lens. It is not a stand-alone initiative or program—it is integrated in our systems, and our processes. Our principles guide how we make decisions, treat each other, and serve our clients.

Workforce

As of December 31, 2025, we employed 3,376 employees, with none represented by a collective bargaining agreement. This represents a decrease of 105 employees from December 31, 2024. As of December 31, 2025, approximately 67.2% of our workforce was female, 32.6% was male, and 0.2% have not declared. The executive team is comprised of 37.5% female and 62.5% male, and the Company’s senior leadership team was 32.4% female and 67.6% male.

Commitment to Community / Volunteerism

We are “all-in” when it comes to giving back—with time, money, and heart. We have a vested interest in the strength of our communities and strive to make them better places to live and work. Each year, the Company creates commitment to community plans for all our markets, which includes donating a portion of our net income before tax for charitable purposes. These plans help align strategies for philanthropy, volunteering and leadership, financial education outreach, community development, and sustainability.

We encourage employees to take active leadership roles within their communities to further demonstrate our principles and help us respond to the needs of the markets we serve. In 2025, the Company provided employees an opportunity to participate in a Bank-sponsored service project annually, marking the second Wednesday in September as our Commitment to Community Volunteer Day. We closed all offices in the afternoon on Volunteer Day so employees could lend a hand in their community, either as teams or as individuals. We have also implemented a Volunteer Time benefit, which allows employees to utilize up to eight work hours each year to participate in volunteer activities of their choosing.

Employee Engagement

Our employee engagement strategy prioritizes creating a work environment where every employee feels heard and valued. We measure our success by how effectively we address workplace needs and empower local leaders to activate meaningful progress.

To deepen our understanding of organizational dynamics, we conduct an annual census survey each fall and administer strategic pulse surveys throughout the year. These insights drive innovative solutions tailored to our employees’ needs.

Leaders across the organization are held accountable for fostering engagement through active participation, sharing team results, and creating actionable engagement plans. The aggregated results serve as a key indicator of the overall health of our workforce and are shared with the Company’s board of directors (the “Board”).

Compensation and Benefits

We strive to provide competitive wages, benefits, and programs that meet the varying needs of our workforce. We continually review our programs to ensure we remain competitive and take care of our employees.

Our compensation philosophy is designed to attract, retain, and motivate talent through fair, competitive, and performance-driven pay. We benchmark roles against market data to ensure competitiveness, maintain a clear job architecture for internal equity and career progression, and reward performance through merit increase and incentive programs.

The approach we take in our benefit offerings is a holistic one to address our employees’ total well-being, which includes aspects of their health, physical, mental/emotional, social, and financial needs.

We offer the following compensation and benefit programs as part of our total rewards package:

•Competitive Total Compensation

•Base salary

•Short-term Incentive Plan (for eligible employees)

•Long-term Incentive Plan (for eligible employees)

•Referral incentive programs

•Comprehensive Benefit Programs

•Medical, dental, and vision plans

•401(k) plan with a 100% match on the first 6% contributed

•Paid time off

•Health savings accounts with employer contribution

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•Flexible spending accounts

•Company paid childcare assistance program

•Student debt employer repayment program

•Additional Benefits: short-term disability; long-term disability; employee assistance program; free or discounted banking products and services; wellness program; and flexible work arrangements

Growth and Development

As part of our commitment to fostering a dynamic and competitive workforce, we have invested significant time and resources to develop and empower our talent. We made meaningful progress in our development programs centered on emotional intelligence, and manager effectiveness. These initiatives were further enhanced by role-specific training programs and on-demand learning opportunities, ensuring our employees are equipped with the skills necessary to excel in their roles.

Better Together

At First Interstate Bank we recognize that fostering an inclusive workplace contributes to innovation, enhances decision-making, and improves client experiences. Our commitment to inclusion is reflected not only within our Company but also in the communities where we live and work. We take pride in creating a workplace that values the unique skills and experiences our employees bring. We are committed to advocating for the rights and respect of all and actively participate in achieving this by setting an example of this leadership in the communities we call home.

To help ensure our educational and connection opportunities align with the needs of our employees, we have an employee Council that is comprised of 18 individuals across the footprint from various departments and with a range of tenure with the Company (2-26 years). The Council meets quarterly with smaller working groups convening as necessary to drive optional education opportunities, employee engagement, and communications that fit within our overall business strategy.

Our Employee Engagement survey allows us to track year over year progress, through the Culture of Inclusion Index questions, giving us insight into areas of strengths and opportunities for improvement, helping us continuously refine our approach to inclusion and workplace culture.

In conjunction with our Learning & Development team, we created Better Together, a voluntary learning opportunity to ensure employees understand what belonging means at First Interstate, how it can enhance our work with colleagues and clients, and how an inclusive culture strengthens team performance. Better Together is now the foundational learning opportunity for incoming employees and creates a common understanding among new and more tenured employees. Launched in the third quarter of 2024, 78% of our workforce has engaged with Better Together as of December 31, 2025.

We continued our Collective Learning Series, a monthly educational and community-building webinar that brings together employees to share experiences, perspectives, and learn more about our team and the communities we serve. Now in its third year, this series has experienced remarkable growth, with attendance climbing significantly year after year. Mental health remains one of our most sought-after topics, and we proudly recognized Men’s Mental Health Month in June 2025. In August 2025, our CEO partnered with Community Banking and Contact Center leadership for a standout event focused on creating inclusive environments for clients. Additional sessions explored critical themes such as Substance Abuse Prevention Month, generational diversity in the workplace, and Eating Disorder Awareness — each contributing to meaningful conversations and engagement across our organization.

We believe we are better together and are committed to moving forward while making an impact and difference for all communities and employees. We look forward to another year of providing voluntary resources and engagement opportunities that we believe bring value to our employees, serve our mission of helping people get to where they want to be, and support the communities where we live and work.

Website Access to SEC Filings

The Company’s electronic filings with the SEC, including Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and Proxy Statements, as well as amendments to these reports and statements filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, are made available at no cost through our website at www.FIBK.com by clicking through the “Financials” tab found there and selecting “SEC Filings,” as soon as reasonably practicable after the Company files such material with, or furnishes such materials to, the SEC. The Company’s SEC filings are also available through the SEC’s website at www.sec.gov. In addition, we routinely post important information for investors on our website at www.FIBK.com. We use this website as a means of disclosing material information in compliance with our disclosure obligations under Regulation FD. Accordingly, investors should monitor our website, in addition to following our press releases, SEC filings, public conference calls, presentations and webcasts. Our website and the information contained therein or connected thereto is not intended to be incorporated by reference into this report and should not be considered a part of this report, and the referenced websites are not intended to act as active hyperlinks.