TRICO BANCSHARES /

Years Ended December 31, 2025, 2024 and 2023

Note 1 –Summary of Significant Accounting Policies

Description of Business and Basis of Presentation

TriCo Bancshares (the “Company” or “we”) is a California corporation organized to act as a bank holding company for Tri Counties Bank (the “Bank”). The Company and the Bank are headquartered in Chico, California. The Bank is a California-chartered bank that is engaged in the general commercial and retail banking business in 31 California counties. The consolidated financial statements are prepared in accordance with accounting policies generally accepted in the United States of America and general practices in the banking industry. All adjustments necessary for a fair presentation of these consolidated financial statements have been included and are of a normal and recurring nature. The financial statements include the accounts of the Company and its wholly-owned subsidiary. All inter-company accounts and transactions have been eliminated in consolidation.

The Company hastwo capital subsidiary business trusts (collectively, the Trusts) organized by the Company that issued trust preferred securities. For financial reporting purposes, the Company’s investments in the Trusts of $1.2 million are accounted for under the equity method and, accordingly, are included in other assets on the consolidated balance sheets. The subordinated debentures issued and guaranteed by the Company and held by the Trusts are reflected as debt on the Company’s consolidated balance sheets.

Use of Estimates in the Preparation of Financial Statements

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires Management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

Segment and Significant Group Concentration of Credit Risk

The Company grants agribusiness, commercial, consumer, and residential loans to customers located throughout California. The Company has a diversified loan portfolio generally consistent with the business segments located in this geographical area. While the chief operating decision-maker (CODM) may monitor the revenue streams of the various products and services, operations are managed, financial performance is evaluated, and decisions are generally made on a Company-wide basis. Discrete financial information is not available other than on a Company-wide basis. Accordingly, operations are considered by management to be aggregated inone reportable operating segment.

Geographical Descriptions

For the purpose of describing the geographical location of the Company’s operations, the Company has defined northern California as that area of California north of, and including, Stockton to the east and San Jose to the west; central California as that area of the state south of Stockton and San Jose, to and including, Bakersfield to the east and San Luis Obispo to the west; and southern California as that area of the state south of Bakersfield and San Luis Obispo.

Cash and Cash Equivalents

For purposes of the consolidated statements of cash flows, cash and cash equivalents include cash on hand, amounts due from banks, and federal funds sold. Net cash flows are reported for loan and deposit transactions and other borrowings.

Non-Marketable and Other Equity Securities

Non-marketable and other equity securities include qualified public welfare investments and venture capital/private equity funds. The Company's accounting for investments in non-marketable and other equity securities depends on several factors, including the level of ownership, power to control and the legal structure of the subsidiary making the investment. We base our accounting for such securities on: (i) fair value accounting, (ii) measurement alternative for other investments without a readily determinable fair value, and (iii) equity method accounting. During the twelve months ended December 31, 2025, 2024 and 2023, the Company recognized an insignificant amount of earnings and losses in the consolidated statements of net income related to changes in the fair value of non-marketable and other equity securities.

Debt Securities

The Company classifies its debt securities into one of three categories: trading, available for sale or held to maturity. Trading securities are bought and held principally for the purpose of selling in the near term and changes in the value of these securities are recorded through earnings. Held to maturity securities are those securities which the Company has the ability and intent to hold until maturity. These securities are carried at cost adjusted for amortization of premium and accretion of discount, computed by the effective interest method over their contractual lives. All other securities not included in trading or held to maturity are classified as available for sale. AFS securities are

59 TriCo Bancshares 2025 10-K recorded at fair value. Unrealized gains and losses, net of the related tax effect, on available for sale securities are reported as a separate component of other accumulated comprehensive income in shareholders’ equity until realized. Discounts are amortized or accreted over the expected life of the related investment security as an adjustment to yield using the effective interest method. Premiums on callable debt securities are generally amortized to the earliest call date of the security with the exception of mortgage backed securities, where estimated prepayments, if any, are considered. Dividend and interest income are recognized when earned. Realized gains and losses are derived from the amortized cost of the security sold. The Company did not have a significant level of debt securities classified as trading during the three-year period ended December 31, 2025.

The Company has made a policy election to exclude accrued interest from the amortized cost basis of debt securities and report accrued interest separately in the consolidated balance sheets. A debt security is placed on nonaccrual status at the time any principal or interest payments become more than 90 days delinquent or if full collection of interest or principal becomes uncertain. Accrued interest for a security placed on nonaccrual is reversed against interest income. There wasno accrued interest related to debt securities reversed against interest income for the years ended December 31, 2025, 2024 or 2023.

Restricted Equity Securities

Restricted equity securities represent the Company’s investment in the stock of the Federal Home Loan Bank of San Francisco (“FHLB”) and are carried at par value, which reasonably approximates its fair value. While technically these are considered equity securities, there is no market for FHLB stock. Therefore, the shares are considered as restricted investment securities. Management periodically evaluates FHLB stock for other-than-temporary impairment. Management’s determination of whether these investments are impaired is based on its assessment of the ultimate recoverability of cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of cost is influenced by criteria such as (1) the significance of any decline in net assets of the FHLB as compared to the capital stock amount for the FHLB and the length of time this situation has persisted, (2) commitments by the FHLB to make payments required by law or regulation and the level of such payments in relation to the operating performance of the FHLB, (3) the impact of legislative and regulatory changes on institutions and, accordingly, the customer base of the FHLB, and (4) the liquidity position of the FHLB.

As a member of the FHLB system, the Bank is required to maintain a minimum level of investment in FHLB stock based on specific percentages of its outstanding mortgages, total assets, or FHLB advances. The Bank may request redemption at par value of any stock in excess of the minimum required investment. Stock redemptions are at the discretion of the FHLB. Both cash and stock dividends are reported as income when received.

Loans Held for Sale

Loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by aggregate outstanding commitments from investors of current investor yield requirements. Net unrealized losses are recognized through a valuation allowance by charges to non-interest income.

Mortgage loans held for sale are generally sold with the mortgage servicing rights retained by the Company. Gains or losses on the sale of loans that are held for sale are recognized at the time of the sale and determined by the difference between net sale proceeds and the net book value of the loans less the estimated fair value of any retained mortgage servicing rights.

Loans

Loans that Management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at the principal amount outstanding, net of deferred loan fees and costs. Loan origination and commitment fees and certain direct loan origination costs are deferred, and the net amount is amortized as an adjustment to the related loan’s yield over the actual life of the loan. Loans on which the accrual of interest has been discontinued are designated as nonaccrual loans.

Loans are placed in nonaccrual status when reasonable doubt exists as to the full, timely collection of interest or principal, or a loan becomes contractually past due by 90 days or more with respect to interest or principal and is not well secured and in the process of collection. When a loan is placed on nonaccrual status, all interest previously accrued but not collected is reversed. Income on such loans is then recognized only to the extent that cash is received and where the future collection of principal is considered probable. Interest accruals are resumed on such loans only when they are brought fully current with respect to interest and principal and when, in the judgment of Management, the loan is estimated to be fully collectible as to both principal and interest. Accrued interest receivable is not included in the calculation of the allowance for credit losses.

Allowance for Credit Losses

The Company performs an ACL evaluation on its loan and lease portfolio and its HTM and AFS securities portfolios. The ACL on loan and lease portfolio and HTM securities are provided through an expected loss methodology referred to as CECL methodology. The ACL on AFS securities is provided when a credit loss is deemed to have occurred for securities which the Company does not intend to sell or is not required to sell. The CECL methodology also applies to credit exposures on off-balance-sheet loan commitments.

60 TriCo Bancshares 2025 10-K

Loans

The ACL is a valuation account that is deducted from the loan's amortized cost basis to present the net amount expected to be collected on the loans. Loans are charged off against the allowance when management believes the recorded loan balance is confirmed as uncollectible. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. Regardless of the determination that a charge-off is appropriate for financial accounting purposes, the Company manages its loan portfolio by continually monitoring, where possible, a borrower's ability to pay through the collection of financial information, delinquency status, borrower discussion and the encouragement to repay in accordance with the original contract or modified terms, if appropriate.

The ACL consists of two primary components: (1) the determination of an ACL for loans that are individually identified and analyzed and (2) establishment of an ACL for loans collectively analyzed. To determine the collectively analyzed portion of the ACL, the Company identified various portfolio segments based on loan attributes such as, but not limited to; collateral type and loan purpose or use, to ensure loans with similar risk characteristics are measured on a collective basis. The Company utilizes three different loss model configurations and assigned each of the portfolio segments to one of the three loss model configurations. Historical credit loss experience for financial institutions nationwide, paired with relevant forecasts of macroeconomic conditions, forms the basis for the estimate of expected credit losses amongst the collectively analyzed loan portfolio. Further, each of the three loss model configurations utilized by the Company incorporate unique inputs, such as the following:

(1) Commercial Real Estate: origination vintage, delinquency status, loan-to-value as of the origination date, stated maturity date, property type, and property status

(2) Commercial and Industrial: loan size, credit spread at origination, risk grade, business sector, and loan type

(3) Consumer: FICO, origination vintage, product type, and state geography if applicable

After quantitative considerations, management evaluates the need for additional qualitative adjustments that consider the expected impact of certain factors not fully captured in the quantitative and macroeconomic reserve calculations. These qualitative adjustments may apply to the collectively analyzed pool as a whole, one or more of the three loss models, or to one or more of the loan portfolio segments.

Purchased financial assets with a more-than-insignificant amount of credit deterioration since origination (“PCD assets”) that are measured at amortized cost, the initial allowance for credit losses is added to the purchase price rather than reported as a provision for credit losses. Subsequent changes in the allowance for credit losses on PCD assets are recognized through the provision for credit losses.

HTM Securities

For HTM debt securities, the Company measures expected credit losses on held-to-maturity debt securities on a collective basis by major security type, then further disaggregated by sector and bond rating. Accrued interest receivable on held-to-maturity (HTM) debt securities is excluded from the estimate of credit losses. The estimate of expected credit losses considers historical credit loss information that is adjusted for current condition and reasonable and supportable forecasts based on current and expected changes in credit ratings and default rates. Nearly all of the Company's HTM securities are issued by the U. S. Government entities or agencies, and based on the absence of any historical or expected losses, all qualify for a zero loss assumption. Therefore, no allowance for credit losses has been recognized during the years ended December 31, 2025, 2024 or 2023.

AFS Securities

The Company evaluates available for sale debt securities in an unrealized loss position to determine whether the decline in the fair value below the amortized cost basis (impairment) is due to credit-related factors or noncredit-related factors. Any impairment that is not credit related is recognized in other comprehensive income, net of applicable taxes. Credit-related impairment is recognized as an allowance for credit losses on the balance sheet, limited to the amount by which the amortized cost basis exceeds the fair value, with a corresponding adjustment to earnings. Both the allowance for credit losses and the adjustment to net income may be reversed if conditions change. However, if the Company intends to sell an impaired available for sale debt security or more likely than not will be required to sell such a security before recovering its amortized cost basis, the entire impairment amount is recognized in earnings with a corresponding adjustment to the security's amortized cost basis. In evaluating available for sale debt securities in unrealized loss positions for impairment and the criteria regarding its intent or requirement to sell such securities, the Company considers the extent to which fair value is less than amortized cost, whether the securities are issued by the federal government or its agencies, whether downgrades by bond rating agencies have occurred, and the results of reviews of the issuers' financial condition, among other factors. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the ACL when management believes the uncollectability of an available for sale debt security is confirmed or when either of the criteria regarding intent or requirement to sell is met. No security credit losses were recognized during the years ended December 31, 2025, 2024 or 2023.

Unfunded commitments

The Company is required to include unfunded commitments that are expected to be funded in the future within the allowance for credit loss calculation, other than those that are unconditionally cancellable. To arrive at that reserve, the reserve percentage determined within the same three loss models described above is applied to the unused portion of the expected commitment balance and is multiplied by the expected funding rate. To determine the expected funding rate, the Company uses a historical utilization rate for each segment. The allowance for credit losses for off-balance-sheet credit risk exposures is reported in other liabilities in the condensed consolidated balance sheets.

61 TriCo Bancshares 2025 10-K

Real Estate Owned

Real estate owned (REO) includes assets acquired through, or in lieu of, loan foreclosure. REO is held for sale and are initially recorded at fair value less estimated costs to sell at the date of acquisition, establishing a new cost basis. Physical possession of residential real estate property collateralizing a consumer mortgage loan occurs when legal title is obtained upon completion of foreclosure or when the borrower conveys all interest in the property to satisfy the loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Any write-downs based on the asset’s fair value less costs to sell at the date of acquisition are charged to the allowance for loan and lease losses. Any recoveries based on the asset’s fair value less estimated costs to sell in excess of the recorded value of the loan at the date of acquisition are recorded to the allowance for loan and lease losses. These assets are subsequently accounted for at lower of cost or fair value less estimated costs to sell. If fair value declines subsequent to foreclosure, a valuation allowance is recorded through expense. Operating costs after acquisition are expensed. Revenue and expenses from operations and changes in the valuation allowance are included in other non-interest expense, along with the gain or loss on sale of REO.

Premises and Equipment

Land is carried at cost. Land improvements, buildings and equipment, including those acquired under capital lease, are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expenses are computed using the straight-line method over the shorter of the estimated useful lives of the related assets or lease terms. Asset lives range from 3-10 years for furniture and equipment and 15-40 years for land improvements and buildings.

Company Owned Life Insurance

The Company has purchased life insurance policies on certain key executives. Company owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement.

As a result of current tax law and the nature of these policies, the Bank records any increase in cash value of these policies as nontaxable non-interest income. If Management decided to surrender any of the policies prior to the death of the insured, such surrender may result in a tax expense associated with the life-to-date cumulative increase in cash value of the policy. If the Bank retains such policies until the death of the insured, the Bank would receive nontaxable proceeds from the insurance company equal to the death benefit of the policies. The Bank has entered into Joint Beneficiary Agreements (JBAs) with certain of the insured that provide some level of sharing of the death benefit, less the cash surrender value, among the Bank and the beneficiaries of the insured upon the receipt of death benefits.

Goodwill, Other Intangible and Long-Lived Assets

Goodwill represents the excess of costs over fair value of net assets of businesses acquired from a business combination. The Company has an identifiable intangible asset consisting of core deposit intangibles (“CDI”). CDI are amortized over their respective estimated useful lives and reviewed periodically for impairment. Goodwill and other intangible assets acquired in a business combination and determined to have an indefinite useful life are not amortized, but instead tested for impairment at least annually. Other intangible assets with estimable useful lives are amortized over their respective estimated useful lives to their estimated residual values, and reviewed periodically for impairment.

As of September 30 of each year, goodwill is tested for impairment, and is tested for impairment more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount exceeds the asset’s fair value.

Long-lived assets, such as premises and equipment, and purchased intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets to be disposed of would be separately presented in the balance sheet and reported at the lower of the carrying amount or fair value less costs to sell, and are no longer depreciated. The assets and liabilities of a disposed group classified as held for sale would be presented separately in the appropriate asset and liability sections of the consolidated balance sheet.

Mortgage Servicing Rights

Mortgage servicing rights (“MSR”) represent the Company’s right to a future stream of cash flows based upon the contractual servicing fee associated with servicing mortgage loans. Our MSR arise from residential and commercial mortgage loans that we originate and sell, but retain the right to service the loans. The net gain from the retention of the servicing right is included in gain on sale of loans in non-interest income when the loan is sold. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds and default rates and losses. Servicing fees, when earned, and changes in fair value of the MSR, are recorded in non-interest income.

The Company accounts for MSR at fair value. The determination of fair value of our MSR requires management judgment because they are not actively traded. The determination of fair value for MSR requires valuation processes which combine the use of discounted cash flow models and extensive analysis of current market data to arrive at an estimate of fair value. The cash flow and prepayment assumptions used in our discounted cash flow model are based on empirical data drawn from the historical performance of our MSR, which we believe

62 TriCo Bancshares 2025 10-K are consistent with assumptions used by market participants valuing similar MSR, and from data obtained on the performance of similar MSR. The key assumptions used in the valuation of MSR include mortgage prepayment speeds and the discount rate. These variables can, and generally will, change from quarter to quarter as market conditions and projected interest rates change. The key risks inherent with MSR are prepayment speed and changes in interest rates.

Leases

The Company records a right-of-use asset (“ROUA”) on the consolidated balance sheets for those leases that convey rights to control use of identified assets for a period of time in exchange for consideration. The Company is also required to record a lease liability on the consolidated balance sheets for the present value of future payment commitments. Substantially all of the Company’s leases are comprised of operating leases in which the Company is lessee of real estate property for branches, ATM locations, and general administration and operations. The Company has elected not to include short-term leases (i.e. leases with initial terms of twelve months or less) within the ROUA and lease liability. Known or determinable adjustments to the required minimum future lease payments are included in the calculation of the Company’s ROUA and lease liability. Adjustments to the required minimum future lease payments that are variable and will not be determinable until a future period, such as changes in the consumer price index, are included as variable lease costs. Additionally, expected variable payments for common area maintenance, taxes and insurance are not unknown and not determinable at lease commencement and therefore, are not included in the determination of the Company’s ROUA or lease liability.

The value of the ROUA and lease liability is impacted by the amount of the periodic payment required, length of the lease term, and the discount rate used to calculate the present value of the minimum lease payments. The Company’s lease agreements often include one or more options to renew at the Company’s discretion. If at lease inception, the Company considers the exercising of a renewal option to be reasonably certain, the Company will include the extended term in the calculation of the ROU asset and lease liability. The Company uses the rate implicit in the lease whenever this rate is readily determinable. As this rate is rarely determinable, the Company utilizes its incremental borrowing rate at lease inception, on a collateralized basis, over a similar term.

Off-Balance Sheet Credit Related Financial Instruments

In the ordinary course of business, the Company has entered into commitments to extend credit, including commitments under credit card arrangements, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded when they are funded.

Low Income Housing Tax Credits

The Company accounts for low income housing tax credits and the related qualified affordable housing projects using the proportional amortization method. Under the proportional amortization method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense (benefit). Upon entering into a qualified affordable housing project, the Company records, in other liabilities, the entire amount that it has agreed to invest in the project, and an equal amount, in other assets, representing its investment in the project. As the Company disburses cash to satisfy its investment obligation, other liabilities are reduced. Over time, as the tax credits and other tax benefits of the project are realized by the Company, the investment recorded in other assets is reduced using the proportional amortization method.

Income Taxes

The Company’s accounting for income taxes is based on an asset and liability approach. The Company recognizes the amount of taxes payable or refundable for the current year, and deferred tax assets and liabilities for the future tax consequences that have been recognized in its financial statements or tax returns. The measurement of tax assets and liabilities is based on the provisions of enacted tax laws. A valuation allowance, if needed, reduces deferred tax assets to the expected amount most likely to be realized. Realization of deferred tax assets is dependent upon the generation of a sufficient level of future taxable income and recoverable taxes paid in prior years. Although realization is not assured, management believes it is more likely than not that all of the deferred tax assets will be realized.

A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. Interest and/or penalties related to income taxes are reported as a component of non-interest income.

Share-Based Compensation

Compensation cost is recognized for stock options and restricted stock awards issued to employees and directors, based on the fair value of the awards at the date of grant. The estimate of the fair value of stock options and performance based restricted awards are based on a Black-Scholes or Monte Carlo model, respectively, while the market price of the common stock at the date of grant is used for time based restricted awards. Compensation cost is recognized over the required service period, generally defined as the vesting or measurement period. The Company’s accounting policy is to recognize forfeitures as they occur.

Earnings per Share

Basic earnings per share represents income available to common shareholders divided by the weighted-average number of common shares outstanding during the period. There are no unvested share-based payment awards that contain rights to nonforfeitable dividends (participating securities). Diluted earnings per share reflects additional common shares that would have been outstanding if dilutive potential common shares had been issued, as well as any adjustments to income that would result from assumed issuance. Potential common shares that may be issued by the Company relate solely from outstanding stock options and restricted stock units, and are determined using the treasury stock method.

63 TriCo Bancshares 2025 10-K

Revenue Recognition

The Company earns a variety of revenue including interest and fees from customers. Certain sources of revenue are recognized within interest or fee income and are outside of the scope of ASC 606. Other sources of revenue fall within the scope of ASC 606 and are generally recognized within noninterest income.

The Company recognizes revenue when the performance obligations related to the transfer of goods or services under the terms of a contract are satisfied. Some obligations are satisfied at a point in time while others are satisfied over a period of time. Revenue is recognized as the amount of consideration to which the Company expects to be entitled to in exchange for transferring goods or services to a customer. When consideration includes a variable component, the amount of consideration attributable to variability is included in the transaction price only to the extent it is probable that significant revenue recognized will not be reversed when uncertainty associated with the variable consideration is subsequently resolved. Generally, the variability relating to the consideration is explicitly stated in the contracts, but may also arise from the Company's customer business practices, for example, waiving certain fees related to customer’s deposit accounts. The Company's contracts generally do not contain terms that require significant judgment to determine the variability impacting the transaction price. The Company has evaluated the nature of its revenue streams and determined that further disaggregation of revenue into more granular categories beyond what is presented in Note 18 was not necessary. The following are descriptions of revenues within the scope of ASC 606.

Deposit service charges

The Company earns fees from its deposit customers for account maintenance, transaction-based and overdraft services. Account maintenance fees consist primarily of account fees and analyzed account fees charged on deposit accounts on a monthly basis. The performance obligation is satisfied and the fees are recognized on a monthly basis as the service period is completed. Transaction-based fees on deposit accounts are charged to deposit customers for specific services provided to the customer, such as non-sufficient funds fees, overdraft fees, and wire fees. The performance obligation is completed as the transaction occurs and the fees are recognized at the time each specific service is provided to the customer.

Debit and ATM interchange fees

Debit and ATM interchange income represent fees earned when a debit card issued by the Company is used. The Company earns interchange fees from debit cardholder transactions through the Visa payment network. Interchange fees from cardholder transactions represent a percentage of the underlying transaction value and are recognized daily, concurrently with the transaction processing services provided to the cardholder. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the cardholders’ debit card. Certain expenses directly associated with the credit and debit card are recorded on a net basis with the interchange income.

Commission on sale of non-deposit investment products

Commissions on sale of non-deposit investment products consist of fees earned from advisory asset management, trade execution and administrative fees from investments. Advisory asset management fees are variable, since they are based on the underlying portfolio value, which is subject to market conditions and asset flows. Advisory asset management fees are recognized quarterly and are based on the portfolio values at the end of each quarter. Brokerage accounts are charged commissions at the time of a transaction and the commission schedule is based upon the type of security and quantity. In addition, revenues are earned from selling insurance and annuity policies. The amount of revenue earned is determined by the value and type of each instrument sold and is recognized at the time the policy or contract is written.

Merchant fee income

Merchant fee income represents fees earned by the Company for card payment services provided to its merchant customers. The Company outsources these services to a third party to provide card payment services to these merchants. The third party provider passes the payments made by the merchants through to the Company. The Company, in turn, pays the third party provider for the services it provides to the merchants. These payments to the third party provider are recorded as expenses as a net reduction against fee income. In addition, a portion of the payment received represents interchange fees which are passed through to the card issuing bank. Income is primarily earned based on the dollar volume and number of transactions processed. The performance obligation is satisfied and the related fee is earned when each payment is accepted by the processing network.

Gain/loss on other real estate owned, net

The Company records a gain or loss from the sale of other real estate owned when control of the property transfers to the buyer, which generally occurs at the time of an executed deed of trust. When the Company finances the sale of other real estate owned to the buyer, the Company assesses whether the buyer is committed to perform their obligations under the contract and whether collectability of the transaction price is probable. Once these criteria are met, the other real estate owned asset is derecognized and the gain or loss on sale is recorded upon the transfer of control of the property to the buyer. In determining the gain or loss on sale, the Company adjusts the transaction price and related gain or loss on sale if a significant financing component is present. Gains or losses from transactions associated with other real estate owned are recorded as a component of non-interest expense.

64 TriCo Bancshares 2025 10-K

Reclassifications

Certain amounts reported in previous consolidated financial statements have been reclassified and recalculated to conform to the presentation in this report. These reclassifications did not affect previously reported amounts of net income, total assets or total shareholders’ equity.

Note 2 –Accounting Standards Update

Accounting standards adopted in the current period

Accounting standards yet to be adopted

Note 3 –Investment Securities

The amortized cost and estimated fair values of investment securities classified as available for sale and held to maturity are summarized in the following tables:

There wasno allowance for credit losses recorded for the held to maturity debt portfolio as of or for the years ended December 31, 2025 and 2024.

65 TriCo Bancshares 2025 10-K

During the year ended December 31, 2025, proceeds from sales of debt securities totaled $79.2 million, resulting in gross losses of $3.2 million. During the year ended December 31, 2024, proceeds from sales of debt securities totaled $31.5 million, resulting in gross losses of $2.9 million. In addition, during 2024 the Company participated in and completed an exchange offering with Visa, which resulted in a gain of $2.9 million. There wereno sales of debt securities during the year ended 2023. Investment securities with an aggregate carrying value of $839.6 million and $716.0 million at December 31, 2025 and 2024, respectively, were pledged as collateral for specific borrowings, lines of credit and local agency deposits.

The amortized cost and estimated fair value of debt securities at December 31, 2025 by contractual maturity are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. At December 31, 2025, obligations of U.S. government and agencies with an amortized cost basis totaling $1.2 billion consist almost entirely of residential real estate mortgage-backed securities whose contractual maturity, or principal repayment, will follow the repayment of the underlying mortgages. For purposes of the following table, the entire outstanding balance of these mortgage-backed securities issued by U.S. government corporations and agencies is categorized based on final maturity date. At December 31, 2025, the Company estimates the average remaining life of these mortgage-backed securities issued by U.S. government corporations and agencies to be approximately 6.08 years. Average remaining life is defined as the time span after which the principal balance has been reduced by half.

Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, were as follows:

66 TriCo Bancshares 2025 10-K

The following securities had unrealized losses as of December 31, 2025:

•Obligations of U.S. government corporations and agencies included 134 debt securities with aggregate depreciation of 10.5% from the Company’s amortized cost basis.

•Obligations of states and political subdivisions included 140 debt securities with aggregate depreciation of 8.8% from the Company’s amortized cost basis.

•Corporate bonds included 3 debt securities with aggregate depreciation of 0.9% from the Company’s amortized cost basis.

•Asset backed securities included 24 debt securities with aggregate depreciation of 0.9% from the Company’s amortized cost basis.

•Non-agency collateralized mortgage obligations included 14 debt securities with aggregate depreciation of 12.4% from the Company’s amortized cost basis.

Based on an evaluation of available information including security type, counterparty credit quality, past events, current conditions, and reasonable and supportable forecasts that are relevant to collectability of cash flows, as of December 31, 2025, the Company has concluded that it expects to receive all contractual cash flows from each security held in its AFS and HTM debt securities portfolio. As such, the unrealized losses on these securities were caused by the changes in market interest rates or the widening of market spreads subsequent to the initial purchase of these securities and are not due to the underlying credit of the issuers.

67 TriCo Bancshares 2025 10-K

The Company monitors credit quality of debt securities held-to-maturity through the use of credit rating. The Company monitors the credit rating on a monthly basis. The following table summarizes the amortized cost of debt securities held-to-maturity at the dates indicated, aggregated by credit quality indicator:

Note 4 –Loans

A summary of loan balances follows:

Note 5 –Allowance for Credit Losses

The ACL was $125.8 million as of December 31, 2025 as compared to $125.4 million at December 31, 2024. The provision for credit losses on loans of $10.3 million during the year ended December 31, 2025 was comprised of $1.7 million in reserves on collectively evaluated loans, a reversal of $1.4 million on individually evaluated reserves and most notably, $10.0 million to replenish reserves following the net charge-off activity. The ACL estimate incorporates assumptions from Management surrounding expected trends within certain macro economic indicators, such as U.S. unemployment rates, gross domestic product, corporate borrowing rates and inflation data, as Management observes the performance of these indicators to have a direct impact on the performance of the Company's loan portfolio.

The following tables summarize the activity in the allowance for credit losses, and ending balance of loans, net of unearned fees for the periods indicated.

68 TriCo Bancshares 2025 10-K

69 TriCo Bancshares 2025 10-K

As part of the on-going monitoring of the credit quality of the Company’s loan portfolio, management tracks certain credit quality indicators including, but not limited to, trends relating to (i) the level of criticized and classified loans, (ii) net charge-offs, (iii) non-performing loans, and (iv) delinquency within the portfolio. The Company analyzes loans individually to classify the loans as to credit risk and grading. This analysis is performed annually for all outstanding balances greater than $1.0 million and non-homogeneous loans, such as commercial real estate loans, unless other indicators, such as delinquency, trigger more frequent evaluation. Loans below the $1.0 million threshold and homogenous in nature are evaluated as needed for proper grading based on delinquency and borrower credit scores.

Collateral values may be determined by appraisals obtained through Bank approved, licensed appraisers, qualified independent third parties, public value information (blue book values for autos), sales invoices, or other appropriate means. Appropriate valuations are obtained at initiation of the credit and periodically (every 3-12 months depending on collateral type) once repayment is questionable and the loan has been classified.

The Company utilizes a risk grading system to assign a risk grade to each of its loans. Loans are graded on a scale ranging from Pass to Loss. A description of the general characteristics of the credit quality indicators is as follows:

•Pass – This grade represents loans ranging from acceptable to very little or no credit risk. These loans typically meet most if not all policy standards in regard to: loan amount as a percentage of collateral value, debt service coverage, profitability, leverage, and working capital.

•Special Mention – This grade represents “Other Assets Especially Mentioned” in accordance with regulatory guidelines and includes loans that display some potential weaknesses which, if left unaddressed, may result in deterioration of the repayment prospects for the asset or may inadequately protect the Company’s position in the future. These loans warrant more than normal supervision and attention.

•Substandard – This grade represents “Substandard” loans in accordance with regulatory guidelines. Loans within this rating typically exhibit weaknesses that are well defined to the point that repayment is jeopardized. Loss potential is, however, not necessarily evident. The underlying collateral supporting the credit appears to have sufficient value to protect the Company from loss of principal and accrued interest, or the loan has been written down to the point where this is true. There is a definite need for a well-defined workout/rehabilitation program.

•Doubtful – This grade represents “Doubtful” loans in accordance with regulatory guidelines. An asset classified as Doubtful has all the weaknesses inherent in a loan classified Substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions and values, highly questionable and improbable. Pending factors include proposed merger, acquisition, or liquidation procedures, capital injection, perfecting liens on additional collateral, and financing plans.

•Loss – This grade represents “Loss” loans in accordance with regulatory guidelines. A loan classified as Loss is considered uncollectible and of such little value that its continuance as a bankable asset is not warranted. This classification does not mean that the loan has absolutely no recovery or salvage value, but rather that it is not practical or desirable to defer writing off the loan, even though some recovery may be affected in the future. The portion of the loan that is graded loss should be charged off no later than the end of the quarter in which the loss is identified.

70 TriCo Bancshares 2025 10-K

The following tables present ending loan balances by loan category and risk grade for the periods indicated:

71 TriCo Bancshares 2025 10-K

72 TriCo Bancshares 2025 10-K

73 TriCo Bancshares 2025 10-K

74 TriCo Bancshares 2025 10-K

75 TriCo Bancshares 2025 10-K

Once a loan becomes delinquent and repayment becomes questionable, a Bank collection officer will address collateral shortfalls with the borrower and attempt to obtain additional collateral. If this is not forthcoming and payment in full is unlikely, the Bank will estimate its probable loss, using a recent valuation as appropriate to the underlying collateral less estimated costs of sale, and charge the loan down to the estimated net realizable amount. Depending on the length of time until ultimate collection, the Bank may revalue the underlying collateral and take additional charge-offs as warranted. Revaluations may occur as often as every 3-12 months depending on the underlying collateral and volatility of values. Final charge-offs or recoveries are taken when collateral is liquidated and actual loss is known. Unpaid balances on loans after or during collection and liquidation may also be pursued through lawsuit and attachment of wages or judgment liens on borrower’s other assets.

76 TriCo Bancshares 2025 10-K

The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated:

The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated:

77 TriCo Bancshares 2025 10-K

The following table shows the ending balance of non accrual loans by loan category as of the date indicated:

Interest income on non accrual loans that would have been recognized during the years ended December 31, 2025, 2024, and 2023, if all such loans had been current in accordance with their original terms, totaled $5.0 million, $4.2 million, and $2.5 million, respectively. Interest income actually recognized on these loans during the years ended December 31, 2025, 2024, and 2023 was $1.0 million, $0.8 million, and $1.0 million, respectively.

78 TriCo Bancshares 2025 10-K

The following tables present the amortized cost basis of collateral dependent loans by class of loans as of the following periods:

79 TriCo Bancshares 2025 10-K

Modifications to borrowers experiencing financial difficulty may include interest rate reductions, principal or interest forgiveness, forbearances, term extensions, and other actions intended to minimize economic loss and to avoid foreclosure or repossession of collateral.

The following tables show the amortized cost basis of loans that were both experiencing financial difficulty and modified during the periods presented. The percentage of the amortized cost basis of loans that were modified to borrowers in financial distress as compared to the amortized cost basis of each class of financing receivables is also presented below.

The following table presents the financial effect of loan modifications made to borrowers experiencing financial difficulty during the twelve months ended December 31, 2025:

The following table presents the financial effect of loan modifications made to borrowers experiencing financial difficulty during the twelve months ended December 31, 2024:

There were no loans with payment defaults by borrowers experiencing financial difficulty during the year ended December 31, 2025 which had material modifications in rate, term or principal forgiveness during the twelve months prior to default.

80 TriCo Bancshares 2025 10-K

Note 6 –Real Estate Owned

A summary of the activity in the balance of real estate owned follows:

At December 31, 2025, there wereno additional real estate properties with formal foreclosure proceedings underway.

Note 7 –Premises and Equipment

Depreciation expense for premises and equipment amounted to $5.8 million, $5.6 million, and $5.8 million during the years ended 2025, 2024, and 2023, respectively.

Note 8 –Cash Value of Life Insurance

A summary of the activity in the balance of cash value of life insurance follows:

Note 9 –Goodwill and Other Intangible Assets

81 TriCo Bancshares 2025 10-K

The following table summarizes the Company’s goodwill intangible as of the dates indicated:

Impairment exists when a Company’s carrying value exceeds its fair value. Goodwill is evaluated for impairment annually. At September 30, 2025, the Company had positive equity and the Company elected to perform a qualitative assessment to determine if it was more likely than not that the fair value of the Company exceeded its carrying value, including goodwill. The qualitative assessment indicated that it was more likely than not that the fair value of the reporting unit exceeds its carrying value, resulting inno impairment. For each of the years in the three year period ended December 31, 2025, there wereno impairment charges recognized.

The following table summarizes the Company’s core deposit intangibles (“CDI”) as of the dates indicated:

The Company's remaining net CDI balance of $4.5 million as of December 31, 2025 reflects gross balances recorded from the VRB acquisition on March 25, 2022 totaling $10.6 million and the FNBB acquisition on July 6, 2018 totaling $27.6 million. The following table summarizes the Company’s estimated core deposit intangible amortization (dollars in thousands):

82 TriCo Bancshares 2025 10-K

Note 10 –Mortgage Servicing Rights

The following tables summarize the activity in, and the main assumptions used to determine the fair value of mortgage servicing rights for the periods indicated:

The changes in fair value of MSRs during 2025 were primarily due to changes in mortgage prepayment speeds and changes in principal balances of the underlying mortgages. The changes in fair value of MSRs during 2024 were primarily due to changes in principal balance and mortgage prepayment speeds of the MSRs. The changes in fair value of MSRs during 2023 were primarily due to changes in investor require rate of return, or discount rate, of the MSRs.

Note 11 -Leases

The following table presents the components of lease expense for the periods indicated:

The following table presents supplemental cash flow information related to leases as of the periods ended:

The following table presents the weighted average operating lease term and discount rate as of the periods ended:

83 TriCo Bancshares 2025 10-K

At December 31, 2025, future expected operating lease payments are as follows (in thousands):

Note 12 –Deposits

A summary of the balances of deposits follows:

Overdrawn deposit balances of $2.7 million and $2.5 million were classified as consumer loans at December 31, 2025 and 2024, respectively.

At December 31, 2025, the scheduled maturities of time deposits were as follows (in thousands):

Note 13 –Other Borrowings

A summary of the balances of other borrowings follows:

Other collateralized borrowings are generally overnight maturity borrowings from non-financial institutions that are collateralized by securities owned by the Company. As of December 31, 2025, the Company has pledged as collateral and sold under agreements to repurchase investment securities with fair value of $11.7 million under these other collateralized borrowings.

84 TriCo Bancshares 2025 10-K

The Company maintains a collateralized line of credit with the FHLB. Based on the FHLB stock requirements at December 31, 2025, this line provided for maximum borrowings of $2.4 billion of which none was outstanding. As of December 31, 2025, the Company had designated investment securities with a fair value of $50.3 million and loans with unpaid principal balances totaling $4.4 billion as potential collateral under this collateralized line of credit with the FHLB.

The Company maintains a collateralized line of credit with the Federal Reserve Bank of San Francisco (“FRB”). As of December 31, 2025, this line provided for maximum borrowings of $363.7 million of which none was outstanding. As of December 31, 2025, the Company has loans with unpaid principal balances totaling $506.7 million as potential collateral under this collateralized line of credit with the FRB.

The Company has available unused correspondent banking lines of credit from commercial banks totaling $85.0 million for federal funds transactions at December 31, 2025.

Note 14 –Junior Subordinated Debt

At December 31, 2025, the Company hastwo wholly-owned subsidiary business trusts that had issued $41.2 million of trust preferred securities (the Trusts). Trust preferred securities accrue and pay distributions periodically at specified annual rates as provided in the indentures. The trusts used the net proceeds from the offering to purchase a like amount of subordinated debentures (the Debentures) of the Company. The Debentures are the sole assets of the trusts. The Company’s obligations under the subordinated debentures and related documents, taken together, constitute a full and unconditional guarantee by the Company of the obligations of the trusts. The trust preferred securities are mandatorily redeemable upon the maturity of the Debentures, or upon earlier redemption as provided in the indentures. The Company has the right to redeem the Debentures in whole (but not in part) on or after specific dates, at a redemption price specified in the indentures plus any accrued but unpaid interest to the redemption date. The Company also has a right to defer consecutive payments of interest on the debentures for up tofive years.

The recorded book values of the Debentures issued by the Trusts are reflected as junior subordinated debt in the Company’s consolidated balance sheets. The common stock issued by the Trusts and owned by the Company is recorded in other assets in the Company’s consolidated balance sheets. The recorded book value of the debentures issued by the Trusts, less the recorded book value of the common stock of the Trusts owned by the Company will continue to qualify as Tier 1 or Tier 2 capital under interim guidance issued by the Board of Governors of the Federal Reserve System until only five years remain until their scheduled maturity.

At December 31, 2024, the Company owned three additional Trusts as a result of its acquisition of North Valley Bancorp (NVB) in 2014, andtwo additional tranches of subordinated debt from the acquisition of Valley Republic Bancorp (VRB) in 2022. However, the Company repaid both the holders of the NVB trusts and VRB subordinated debt, with a face values totaling $57.7 million and a recorded book values of $60.2 million, during 2025 resulting in a $2.5 million gain on extinguishment of debt and recorded within other non-interest income.

The following table summarizes the terms and recorded balance of each subordinated debenture as of the dates indicated (dollars in thousands):

Note 15 –Commitments and Contingencies

Restricted Cash Balances — Reserves (in the form of deposits with the San Francisco Federal Reserve Bank) were not required to be maintained as of December 31, 2025 and 2024.

Financial Instruments with Off-Balance-Sheet Risk — The Company is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, standby letters of credit, and deposit account overdraft privilege. Those instruments involve, to varying degrees, elements of risk in excess

85 TriCo Bancshares 2025 10-K of the amount recognized in the balance sheet. The contract amounts of those instruments reflect the extent of involvement the Company has in particular classes of financial instruments.

The Company’s exposure to loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit and standby letters of credit written is represented by the contractual amount of those instruments. The Company uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. The Company’s exposure to loss in the event of nonperformance by the other party to the financial instrument for deposit account overdraft privilege is represented by the overdraft privilege amount disclosed to the deposit account holder.

The following table presents a summary of the Bank’s commitments and contingent liabilities:

Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates of one year or less or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s credit worthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on Management’s credit evaluation of the customer. Collateral held varies, but may include accounts receivable, inventory, property, plant and equipment, residential properties, and income-producing commercial properties.

Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. Those guarantees are primarily issued to support private borrowing arrangements. Most standby letters of credit are issued forone year or less. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. Collateral requirements vary, but in general follow the requirements for other loan facilities.

Deposit account overdraft privilege amount represents the unused overdraft privilege balance available to the Company’s deposit account holders who have deposit accounts covered by an overdraft privilege. The Company has established an overdraft privilege for certain of its deposit account products whereby all holders of such accounts who bring their accounts to a positive balance at least once every thirty days receive the overdraft privilege. The overdraft privilege allows depositors to overdraft their deposit account up to a predetermined level. The predetermined overdraft limit is set by the Company based on account type.

Legal Proceedings — The Company is party to various legal and administrative proceedings and claims. While any litigation contains an element of uncertainty, management believes that neither the Company nor its subsidiaries are a party to any pending legal proceedings that are material, nor is their property the subject of any other material pending legal proceeding at this time. All other legal proceedings are routine and arise out of the ordinary course of the Bank’s business. None of those proceedings are currently expected to have a material adverse impact upon the Company’s and the Bank’s business, their consolidated financial position nor their operations in any material amount not already accrued, after taking into consideration any applicable insurance and any contingency reserves.

Other Commitments and Contingencies—The Company has entered into employment agreements or change of control agreements with certain officers of the Company providing severance payments and accelerated vesting of benefits under supplemental retirement agreements to the officers in the event of a change in control of the Company and termination for other than cause or after a substantial and material change in the officer’s title, compensation or responsibilities.

In April 2024, Visa Inc. announced the commencement of an exchange offer for Visa Class B-1 common stock and the Company subsequently tendered all of its Visa Class B-1 common stock in exchange for a combination of Visa Class B-2 common stock and Visa Class C common stock. Completion of the exchange resulted in a gain of $2.9 million relating to the Visa Class C common stock, which was subsequently disposed. Visa Class B-2 common stock continues to be carried at zero. The Bank owns 6,698 shares of Class B-2 common stock of Visa Inc. which may be convertible into Class A common stock at a conversion ratio of 1.5108 per Class B-2 share. As of December 31, 2025, the value of the Class A shares was $350.71 per share. Utilizing the conversion ratio, the value of unredeemed Class A equivalent shares owned by the Bank was $3.5 million as of December 31, 2025, and has not been reflected in the accompanying consolidated financial statements. The shares of Visa Class B-2 common stock are restricted and may not be transferred. Visa Member Banks are required to fund an escrow account to cover settlements, resolution of pending litigation and related claims. If the funds in the

86 TriCo Bancshares 2025 10-K escrow account are insufficient to settle all the covered litigation, Visa may sell additional Class A shares, use the proceeds to settle litigation, and further reduce the conversion ratio. If funds remain in the escrow account after all litigation is settled, the Class B-2 conversion ratio may be increased to reflect that surplus. Until all U.S. covered litigation obligations have been satisfied or the Applicable Conversion Rate for the Class B-2 common stock reaches zero, there is no dollar cap on the amount of payments that a participating holder and its guarantors may be obligated to make under its Makewhole Agreement.

Mortgage loans sold to investors may be sold with servicing rights retained, with only the standard legal representations and warranties regarding recourse to the Bank. Management believes that any liabilities that may result from such recourse provisions are not significant.

Note 16 –Shareholders’ Equity

Dividends Paid

The Bank paid to the Company cash dividends in the aggregate amounts of $133.4 million, $71.2 million, and $52.8 million in 2025, 2024, and 2023, respectively. The Bank is regulated by the Federal Deposit Insurance Corporation (“FDIC”) and the State of California Department of Financial Protection & Innovation (the “DFPI”). Absent approval from the Commissioner of the DFPI, California banking laws generally limit the Bank’s ability to pay dividends to the lesser of (1) retained earnings or (2) net income for the last three fiscal years, less cash distributions paid during such period. Under this law, at December 31, 2025, the Bank could have paid additional dividends totaling $110.9 million to the Company without the approval of the Commissioner of the DFPI.

Stock Repurchase Program

The Company's Board of Directors has approved the authorization to repurchase up to 2,000,000 shares of the Company’s common stock (the "2025 Repurchase Program" or the "2025 Program"). The Company’s 2025 Share Repurchase Program replaces and supersedes the 2021 Share Repurchase Program which has been terminated as of December 31, 2025. The actual timing of any share repurchases will be determined by the Company's management and therefore the total value of the shares to be purchased under the 2025 Program is subject to change. The 2025 Program has no expiration date but the Board may suspend or discontinue the program at any time. There wereno shares repurchased under the 2025 Program during 2025 and therefore,2,000,000 shares remained available for repurchase as of December 31, 2025.

Under the former 2021 Stock Repurchase Program, the Company repurchased 709,172,379,279, and 150,000 shares for years ended December 31, 2025, 2024 and 2023, respectively.

Stock Repurchased Under Equity Compensation Plans

The Company's shareholder-approved equity compensation plans permit employees to tender recently vested shares in lieu of cash for the payment of withholding taxes on such shares. During the years ended December 31, 2025, 2024, and 2023, employees tendered zero, zero, and 2,506 shares, respectively, of the Company's common stock in connection with option exercises. Employees also tendered 43,271,36,549 and 52,437 shares in connection with other share based awards during December 31, 2025, 2024 and 2023, respectively. In total, shares of the Company's common stock tendered had market values of $1.9 million, $1.4 million, and $2.3 million for the years ended December 31, 2025, 2024 and 2023, respectively. The tendered shares were retired. The market value of tendered shares is the last market trade price at closing on the day an option is exercised or the other share based award vests. Stock repurchased under equity incentive plans are not included in the total of stock repurchased under the 2025 or 2021 Repurchase Programs.

Note 17 –Stock Options and Other Equity-Based Incentive Instruments

On April 16, 2024, the Board of Directors adopted the 2024 Equity Incentive Plan (2024 Plan) which was approved by shareholders on May 23, 2024. The 2024 Plan allows for up to 1,200,000 shares to be issued in connection with equity-based incentives. In conjunction with shareholder approval of the 2024 Plan, the 2019 Equity Incentive Plan (2019 Plan), which allowed for up to 1,500,000 shares to be issued in connection with equity-based incentives, is no longer available for grant issuances. While no new awards can be granted under the 2019 Plan, existing grants continue to be governed by the terms, conditions and procedures set forth in any applicable award agreement.

87 TriCo Bancshares 2025 10-K

Stock option activity is summarized in the following table for the dates indicated:

The Company did not modify any options grants during the three-year period ended December 31, 2025.

The following table shows the total intrinsic value of options exercised, the total fair value of options vested, total compensation costs for options recognized in income, total tax benefit and excess tax benefits recognized in income related to compensation costs for options during the periods indicated:

There wereno stock options granted during 2025, 2024 and 2023, respectively.

Restricted stock unit activity is summarized in the following table for the dates indicated:

The Company uses a Monte Carlo simulation model to determine the grant-date fair value of awards with market plus service conditions (PSU). The weighted average fair value and assumptions used to value the PSU awards granted with market-based performance conditions are as follows:

88 TriCo Bancshares 2025 10-K

The 141,089 of service condition vesting RSUs outstanding as of December 31, 2025 include a feature whereby each RSU outstanding is credited with a dividend amount equal to any common stock cash dividend declared and paid, and the credited amount is divided by the closing price of the Company’s stock on the dividend payable date to arrive at an additional amount of RSUs outstanding under the original grant. Additional RSUs credited through dividends are subject to the same vesting requirements as the original grant. The Company expects to recognize $3.0 million of pre-tax compensation costs related to these service condition vesting RSUs between December 31, 2025 and their vesting dates. The Company did not modify any service condition vesting RSUs during 2025 or 2024.

The Company expects to recognize $1.5 million of pre-tax compensation costs related to the market plus service condition RSUs between December 31, 2025 and their vesting dates. As of December 31, 2025, the number of market plus service condition vesting RSUs outstanding that will actually vest, and be released, may be reduced tozero or increased to 218,228 depending on the total return of the Company’s common stock versus the total return of an index of bank stocks from the grant date to the vesting date. The Company did not modify any market plus service condition vesting RSUs during 2025 or 2024.

The following table shows the compensation costs and excess tax benefits for RSUs recognized in income for the periods indicated:

Note 18 –Non-interest Income and Expense

The components of other non-interest income were as follows:

89 TriCo Bancshares 2025 10-K

Mortgage banking servicing fee income (expense), net of change in value of mortgage loan servicing rights, totaling $1.2 million, $1.3 million, and $1.3 million were recorded within service charges and fees for the years ended December 31, 2025, 2024, and 2023, respectively.

The components of noninterest expense were as follows:

Note 19 –Income Taxes

The components of consolidated income tax expense are as follows (in thousands):

A deferred tax asset or liability is recognized for the tax consequences of temporary differences in the recognition of revenue and expense for financial and tax reporting purposes. The net change during the year in the deferred tax asset or liability results in a deferred tax expense or benefit.

90 TriCo Bancshares 2025 10-K

The Company recognized, as components of tax expense, tax credits and other tax benefits, and amortization expense relating to our investments in Qualified Affordable Housing Projects as follows for the periods indicated (in thousands):

The carrying value of Low Income Housing Tax Credit Funds was $122.8 million and $109.1 million as of December 31, 2025 and 2024, respectively. As of December 31, 2025, the Company has committed to make additional capital contributions to the Low Income Housing Tax Credit Funds in the amount of $59.0 million, and these contributions are expected to be made over the next several years.

The provisions for income taxes applicable to income before taxes for the years ended December 31, 2025, 2024 and 2023 differ from amounts computed by applying the statutory Federal income tax rates to income before taxes. The effective tax rate and the statutory federal income tax rate are reconciled as follows:

91 TriCo Bancshares 2025 10-K

The temporary differences, tax effected, which give rise to the Company’s net deferred tax asset recorded in other assets are as follows for the years indicated (in thousands):

As part of the merger with FNB Bancorp in 2018 and North Valley Bancorp in 2014, TriCo acquired federal and state net operating loss carryforwards, capital loss carryforwards, and tax credit carryforwards. These tax attribute carryforwards will be subject to provisions of the tax law that limit the use of such losses and credits generated by a company prior to the date certain ownership changes occur. There wereno federal and $4.2 million California net operating loss carryforwards subject to these limitations as of December 31, 2025. The amount of the Company’s tax credits that would be subject to these limitations as of December 31, 2025 are $0.3 million and $0.6 million for federal and California, respectively. Due to the limitation, a significant portion of the state tax credits will expire regardless of whether the Company generates future taxable income. As such, the Company has recorded the future benefit of these tax credits on the books at the value which is more likely than not to be realized. These tax loss and tax credit carryforwards expire at various dates through 2033.

The Company believes that a valuation allowance is not needed to reduce the deferred tax assets as it is more likely than not that the results of future operations will generate sufficient taxable income to realize the deferred tax assets, including the tax attribute carryforwards acquired as part of past mergers.

Disclosure of unrecognized tax benefits at December 31, 2025 and 2024 were not considered significant for disclosure purposes. Management does not expect the unrecognized tax benefit will materially change in the next 12 months. During the years ended December 31, 2025 and 2024 the Company did not recognize any significant amounts related to interest and penalties associated with taxes. The Company files income tax returns in the U.S. federal jurisdiction, and California. With few exceptions, the Company is no longer subject to U.S. federal and state/local income tax examinations by tax authorities for years before 2022 and 2021, respectively.

92 TriCo Bancshares 2025 10-K

Cash paid for income taxes, net of refunds, were as follows:

Note 20 –Earnings per Share

Earnings per share have been computed based on the following:

Note 21 –Comprehensive Income (Loss)

Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income. Although certain changes in assets and liabilities, such as unrealized gains and losses on available-for-sale securities, are reported as a separate component of the equity section of the balance sheet, such items, along with net income, are components of comprehensive income. The components of other comprehensive income and related tax effects are as follows:

93 TriCo Bancshares 2025 10-K

The components of accumulated other comprehensive loss, included in shareholders’ equity, are as follows:

Note 22 –Retirement Plans

401(k) Plan

The Company sponsors a 401(k) Plan whereby substantially all employees aged 21 and over with 90 days of service may participate. Participants may contribute a portion of their compensation subject to certain limits based on federal tax laws. The Company provides a discretionary matching contribution equal to 50% of participant’s elective deferrals, up to 4% of eligible compensation. The Company recorded salaries & benefits expense attributable to the 401(k) Plan matching contributions for the years ended:

Employee Stock Ownership Plan

Substantially all employees with at leastone year of service are covered by a discretionary employee stock ownership plan (ESOP). Company shares owned by the ESOP are paid dividends and included in the calculation of earnings per share as common shares outstanding. Contributions are made to the plan at the discretion of the Board of Directors. Expenses related to the Company’s ESOP, included in benefits and other compensation costs under salaries and benefits expense, and contributions to the plan for the years ended were:

Deferred Compensation Plans

The Company has deferred compensation plans for certain directors and key executives, which allow certain directors and key executives designated by the Board of Directors of the Company to defer a portion of their compensation. The Company has purchased insurance on the lives of certain of the participants and intends to hold these policies until death as a cost recovery of the Company’s deferred compensation obligations of $4.9 million and $5.0 million at December 31, 2025 and 2024, respectively. Earnings credits on deferred balances included in non-interest expense are included in the following table:

Supplemental Retirement Plans

The Company has supplemental retirement plans for certain directors and key executives. These plans are non-qualified defined benefit plans and are unsecured and unfunded. The Company has purchased insurance on the lives of the participants and intends to hold these policies until death as a cost recovery of the Company’s retirement obligations. The cash values of the insurance policies purchased to fund the deferred compensation obligations and the supplemental retirement obligations were $137.3 million and $140.1 million at December 31, 2025 and 2024, respectively.

94 TriCo Bancshares 2025 10-K

The Company recorded, in other liabilities, the additional funded status of the supplemental retirement plans of $16.1 million and $16.1 million related to the supplemental retirement plans as of December 31, 2025 and 2024, respectively. These amounts represent the amount by which the projected benefit obligations for these retirement plans exceeded the fair value of plan assets plus amounts previously accrued related to the plans. The projected benefit obligation is recorded in other liabilities.

At December 31, 2025 and 2024, the additional funded status of the supplemental retirement plans of $16.1 million and $16.1 million were offset by a reduction of shareholders’ equity accumulated other comprehensive gain of $11.4 million and $11.3 million, respectively, representing the after-tax impact of the additional funded status of the supplemental retirement plans, and the related deferred tax liability of $4.8 million and $4.8 million, respectively. Amounts recognized as a component of accumulated other comprehensive income (loss) as of year-end that have not been recognized as a component of the combined net period benefit cost of the Company’s defined benefit pension plans are presented in the following table. The Company expects to recognize approximately $0.7 million of the net actuarial loss reported in the following table as of December 31, 2025 as a component of net periodic benefit cost during 2026.

Information pertaining to the activity in the supplemental retirement plans, using a measurement date of December 31, is as follows:

95 TriCo Bancshares 2025 10-K

The following table sets forth the net periodic benefit cost recognized for the supplemental retirement plans:

The following table sets forth assumptions used in accounting for the plans:

The following table sets forth the expected benefit payments to participants and estimated contributions to be made by the Company under the supplemental retirement plans for the years indicated:

Note 23 –Related Party Transactions

In the ordinary course of business, the Bank has made loans to certain of its directors and executive officers (and their associated and affiliated companies). All such loans have been made in accordance with regulatory requirements.

The following table summarizes the activity in these loans for the periods indicated:

Deposits of directors, officers and other related parties to the Bank totaled $35.0 million and $33.1 million at December 31, 2025 and 2024, respectively.

96 TriCo Bancshares 2025 10-K

Note 24 –Fair Value Measurement

The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. In estimating fair value, the Company utilizes valuation techniques that are consistent with the market approach, income approach, and/or the cost approach. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability including assumptions about the risk inherent in a particular valuation technique, the effect of a restriction on the sale or use of an asset and the risk of nonperformance. Securities available-for-sale and mortgage servicing rights are recorded at fair value on a recurring basis. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as loans held for sale, loans held for investment and certain other assets. These nonrecurring fair value adjustments typically involve application of lower of cost or market accounting or impairment write-downs of individual assets.

The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the observable nature of the assumptions used to determine fair value. These levels are:

Level 1 — Valuation is based upon quoted prices for identical instruments traded in active markets.

Level 2 — Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market.

Level 3 — Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques.

Securities available for sale— Securities available for sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions. Level 1 securities include those traded on an active exchange, such as the New York Stock Exchange, U.S. Treasury securities that are traded by dealers or brokers in active over-the-counter markets and money market funds. Level 2 securities include mortgage-backed securities issued by government sponsored entities, municipal bonds and corporate debt securities. The Company had no securities classified as Level 3 during any of the periods covered in these financial statements.

Loans held for sale— Loans held for sale are carried at the lower of cost or fair value. The fair value of loans held for sale is based on what secondary markets are currently offering for loans with similar characteristics. As such, we classify those loans subjected to nonrecurring fair value adjustments as Level 2.

Individually evaluated loans— Loans are not recorded at fair value on a recurring basis. However, from time to time, loans may require individual analysis and an allowance for credit losses is established. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are an example. The fair value of individually evaluated loans is estimated using one of several methods, including collateral value, fair value of similar debt, enterprise value, liquidation value and discounted cash flows. Those individually evaluated loans not requiring an allowance represent loans for which the fair value of the expected repayments or collateral exceed the recorded investments in such loans. Individually evaluated loans where an allowance is established based on the fair value of collateral require classification in the fair value hierarchy. When the fair value of the collateral is based on an observable market price or a current appraised value which uses substantially observable data, the Company records the loan as nonrecurring Level 2. When an appraised value is not available or management determines the fair value of the collateral is below the appraised value, or the appraised value contains a significant unobservable assumption, such as deviations from comparable sales, and there is no observable market price, the Company records the loan as nonrecurring Level 3.

Foreclosed assets— Foreclosed assets include assets acquired through, or in lieu of, loan foreclosure. Foreclosed assets are held for sale and are initially recorded at fair value at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, management periodically performs valuations and the assets are carried at the lower of carrying amount or fair value less cost to sell. When the fair value of foreclosed assets is based on an observable market price or a current appraised value which uses substantially observable data, the Company records the asset as nonrecurring Level 2. When an appraised value is not available or management determines the fair value of the collateral is further impaired below the appraised value, or the appraised value contains a significant unobservable assumption, such as deviations from comparable sales, and there is no observable market price, the Company records the foreclosed asset as nonrecurring Level 3. Revenue and expenses from operations and changes in the valuation allowance are included in other non-interest expense.

Mortgage servicing rights— Mortgage servicing rights are carried at fair value. A valuation model, which utilizes a discounted cash flow analysis using a discount rate and prepayment speed assumptions is used in the computation of the fair value measurement. While the prepayment speed assumption is currently quoted for comparable instruments, the discount rate assumption currently requires a significant degree of management judgment and is therefore considered an unobservable input. As such, the Company classifies mortgage servicing rights subjected to recurring fair value adjustments as Level 3. Additional information regarding mortgage servicing rights can be found in Note 10 in the consolidated financial statements at Item 1 of this report.

97 TriCo Bancshares 2025 10-K

The tables below presents the recorded amount of assets and liabilities measured at fair value on a recurring basis (in thousands):

Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally corresponds with the Company’s quarterly valuation process. There wereno transfers between any levels during 2025 or 2024.

The following table provides a reconciliation of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the years ended December 31, 2025, 2024, and 2023. Had there been any transfer into or out of Level 3 during 2025, 2024, or 2023, the amount included in the “Transfers into (out of) Level 3” column would represent the beginning balance of an item in the period (interim quarter) during which it was transferred (in thousands):

The Company’s method for determining the fair value of mortgage servicing rights is described in Note 1. The key unobservable inputs used in determining the fair value of mortgage servicing rights are mortgage prepayment speeds and the discount rate used to discount cash projected cash flows. Generally, any significant increases in the mortgage prepayment speed and discount rate utilized in the fair value measurement of the mortgage servicing rights will result in a negative fair value adjustments (and decrease in the fair value measurement). Conversely, a decrease in the mortgage prepayment speed and discount rate will result in a positive fair value adjustment (and increase in the fair value measurement). Note 10 contains additional information regarding mortgage servicing rights.

98 TriCo Bancshares 2025 10-K

The following table present quantitative information about recurring Level 3 fair value measurements at December 31, 2025 and 2024:

The tables below present the recorded amount of assets and liabilities measured at fair value on a nonrecurring basis for which a change in fair value was recorded, as of the dates indicated.

The tables below present the net losses resulting from non-recurring fair value adjustments of assets and liabilities for the periods indicated, regardless of whether the asset is still being held at fair value at period end (in thousands):

The individually evaluated loan amount above represents collateral dependent loans with unique risk characteristics that have been adjusted to fair value. When we identify a collateral dependent loan as requiring individual evaluation, we measure the need for credit reserves using the current fair value of the collateral, less selling costs. Depending on the characteristics of a loan, the fair value of collateral is generally estimated by obtaining external appraisals. If we determine that the value of the loan is less than the recorded investment in the loan, we recognize this impairment and adjust the carrying value of the loan to fair value through the allowance for loan and lease losses. The loss represents charge-offs or impairments on collateral dependent loans for fair value adjustments based on the fair value of collateral. The carrying value of loans fully charged-off iszero.

The real estate owned amounts above represents impaired real estate that has been adjusted to fair value. Foreclosed assets represent real estate which the Bank has taken control of in partial or full satisfaction of loans. At the time of foreclosure, other real estate owned is recorded at fair value less costs to sell, which becomes the property’s new basis. Any write-downs based on the asset’s fair value at the date of acquisition are charged to the allowance for loan and lease losses. After foreclosure, management periodically performs valuations such that the real estate is carried at the lower of its new cost basis or fair value, net of estimated costs to sell. Fair value adjustments on other real estate owned are recognized within net loss on real estate owned. The loss represents impairments on non-covered other real estate owned for fair value adjustments based on the fair value of the real estate.

The Company’s property appraisals are primarily based on the sales comparison approach and income approach methodologies, which consider recent sales of comparable properties, including their income generating characteristics, and then make adjustments to reflect the general assumptions that a market participant would make when analyzing the property for purchase. These adjustments may increase or

99 TriCo Bancshares 2025 10-K decrease an appraised value and can vary significantly depending on the location, physical characteristics and income producing potential of each property. Additionally, the quality and volume of market information available at the time of the appraisal can vary from period to period and cause significant changes to the nature and magnitude of comparable sale adjustments. Given these variations, comparable sale adjustments are generally not a reliable indicator for how fair value will increase or decrease from period to period. Under certain circumstances, management discounts are applied based on specific characteristics of an individual property.

The following tables present quantitative information about Level 3 fair value measurements for financial instruments measured at fair value on a nonrecurring basis at December 31, 2025 and 2024:

The estimated fair values of financial instruments that are reported at amortized cost in the Corporation’s consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (in thousands):

The methods and assumptions used to estimate the fair value of each class of financial instruments not measured at fair value are as follows:

Securities held to maturity - This includes mortgage-backed securities issued by government sponsored entities and municipal bonds. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions.

100 TriCo Bancshares 2025 10-K

Loans - Loans are generally valued by discounting expected cash flows using market inputs with adjustments based on cohort level assumptions for certain loan types as well as internally developed estimates at a business segment level. Due to the significance of the unobservable market inputs and assumptions, as well as the absence of a liquid secondary market for most loans, these loans are classified as Level 3. Certain loans are measured based on observable market prices sourced from external data providers and classified as Level 2. Nonaccrual loans are written down and reported at their estimated recovery value which approximates their fair value and classified as Level 3.

Deposits - The estimated fair value of deposits with no stated maturity, such as demand deposit accounts, money market accounts, and savings accounts was the amount payable on demand at the reporting date. The fair value of time deposits was estimated based on a discounted cash flow technique using Level 3 inputs appropriate to the contractual maturity.

Other borrowings - The cash flows were calculated using the contractual features of the advance and then discounted using observable market. These are short-term in nature.

Junior subordinated debt - The fair value of structured financings was estimated based on a discounted cash flow technique using observable market interest rates adjusted for estimated spreads.

Note 25 –TriCo Bancshares Condensed Financial Statements (Parent Only)

Condensed Balance Sheets

101 TriCo Bancshares 2025 10-K

Condensed Statements of Income

Condensed Statements of Comprehensive Income

Condensed Statements of Cash Flows

102 TriCo Bancshares 2025 10-K

Note 26 –Regulatory Matters

The Company and the Bank are subject to various regulatory capital requirements administered by federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory, and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the consolidated financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action specific capital guidelines that involve quantitative measures of assets, liabilities and certain off-balance-sheet items as calculated under regulatory accounting practices. These capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. Quantitative measures established by regulation to ensure capital adequacy require that minimum amounts and ratios of total, Tier 1, and common equity Tier 1capital to risk-weighted assets, and of Tier 1 capital to average assets be maintained. Under applicable capital requirements both the Company and the Bank are required to have a common equity Tier 1 capital ratio of 4.5%, a Tier 1 leverage ratio of 4.0%, a Tier 1 risk-based ratio of 6.0% and a total risk-based ratio of 8.0%. In addition, the Company and the Bank are also required to maintain a capital conservation buffer consisting of common equity Tier 1 capital above 2.5% of minimum risk based capital ratios to avoid restrictions on certain activities including payment of dividends, stock repurchases and discretionary bonuses to executive officers. The additional 2.5% buffer, where applicable, is included in the minimum ratios set forth in the table below. Management believes as of December 31, 2025 and 2024, the Company and Bank meet all capital adequacy requirements to which they are subject.

103 TriCo Bancshares 2025 10-K

Note 27 –Segment Information

The Company's reportable segment is determined by the Chief Executive Officer, who is designated the chief operating decision maker, based upon information provided about the Company's products and services offered, primary banking operations. The segment is also distinguished by the level of information provided to the chief operation decision maker, who uses such information to review performance of various components of the business, which are then aggregated if operating performance, products/services, and customers are similar. The chief operating decision maker will evaluate the financial performance of the Company's business components such as by evaluating revenue streams, significant expenses, and budget to actual results in assessing the Company's segment and in the determination of allocating resources. The chief operating decision maker uses revenue streams to evaluate product pricing and significant expenses to assess performance and evaluate return on assets. The chief operating decision maker uses consolidated net income to benchmark the Company against its competitors. The benchmarking analysis coupled with monitoring of budget to actual results are used in assessing performance and in establishing compensation. Loans and investments are the primary sources of revenue in the banking operation. Interest expense on deposits and borrowings, provisions for credit losses, and payroll comprise the significant expenses in the banking operation. All operations are domestic.

Accounting policies for segments are the same as those described in Note 1. Segment performance is evaluated using consolidated net income. Information reported internally for performance assessment by the chief operating decision maker follows, inclusive of reconciliations of the banking segment totals to the financial statements:

104 TriCo Bancshares 2025 10-K