INTERNATIONAL BANCSHARES CORP

Consolidated Statements of Condition (Unaudited)

Consolidated Statements of Condition, continued (Unaudited)

Consolidated Statements of Income (Unaudited)

(Dollars in Thousands, except per share data)

Consolidated Statements of Income, continued (Unaudited)

(Dollars in Thousands, except per share data)

Consolidated Statements of Comprehensive Income (Unaudited)

Consolidated Statements of Shareholders’ Equity

Three Months ended March 31, 2025 and 2024

(in Thousands, except per share amounts)

Consolidated Statements of Cash Flows (Unaudited)

Consolidated Statements of Cash Flows, continued (Unaudited)

Notes to Consolidated Financial Statements

(Unaudited)

As used in this report, the words “Company,” “we,” “us” and “our” refer to International Bancshares Corporation, a Texas corporation, its five wholly owned subsidiary banks, and other subsidiaries. The information that follows may contain forward-looking statements, which are qualified as indicated under “Special Cautionary Notice Regarding Forward-Looking Information” in Item 2 (Management’s Discussion and Analysis of Financial Condition and Results of Operations) of this report. Our website address is www.ibc.com.

Note 1 — Basis of Presentation

Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (“US GAAP”) and to general practices within the banking industry. Our consolidated financial statements include the accounts of International Bancshares Corporation, and our five wholly-owned bank subsidiaries, International Bank of Commerce, Laredo (“IBC”), Commerce Bank, International Bank of Commerce, Zapata, International Bank of Commerce, Brownsville, International Bank of Commerce, Oklahoma (the “Subsidiary Banks”) and our five wholly-owned non-bank subsidiaries, IBC Trading Company, Premier Tierra Holdings, Inc., IBC Charitable and Community Development Corporation, IBC Capital Corporation, and Diamond Beach Holdings, LLC. Our consolidated financial statements are unaudited but include all adjustments that, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments were of a normal and recurring nature. These financial statements should be read in conjunction with the financial statements and the notes thereto in our latest Annual Report to Shareholders on Form ARS for the fiscal year ended December 31, 2024, furnished to the U.S. Securities and Exchange Commission (“SEC”) on April 21, 2025 (our “2024 Annual Report”). Our consolidated statement of condition at December 31, 2024 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by US GAAP for complete financial statements.

We operate asone segment, banking. The chief operating decision maker (“CODM”) is our chief executive officer. The operating information used by our CODM for purposes of assessing performance and making operating decisions is the consolidated statements presented in this report. We have five active operating subsidiaries, the Subsidiary Banks. Our Subsidiary Banks offer all products and services on the same basis and on the same terms and operate in the same regulatory environment. We apply the provisions of ASC Topic 280, “Segment Reporting,” in determining our reportable segments and related disclosures.

We have evaluated all events or transactions that occurred through the date we issued these financial statements. During this period, we did not have any material recognizable or non-recognizable subsequent events.

Note 2 — Fair Value Measurements

FASB ASC Topic 820, “Fair Value Measurements” (“ASC 820”), defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles, and expands disclosures about fair value measurements. ASC 820 applies to all financial instruments that are being measured and reported on a fair value basis. ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date; it also establishes a fair value hierarchy that prioritizes the inputs used in valuation methodologies into the following three levels:

instruments whose value is determined using pricing models, discounted cash flow methodologies, or other valuation techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.

A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy is set forth below.

The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of March 31, 2025 by level within the fair value measurement hierarchy:

The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of December 31, 2024 by level within the fair value measurement hierarchy:

Available-for-sale securities are classified within Level 1 or 2 of the valuation hierarchy. Equity securities with readily determinable fair values are classified within Level 1. For debt investments classified as Level 2 in the fair value hierarchy, we obtain fair value measurements from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things.

Certain financial assets and financial liabilities are measured at fair value on a non-recurring basis. The instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Our policy is to recognize transfers between levels

at the end of each reporting period, if applicable. There were no transfers between levels of the fair value hierarchy during the three months ended March 31, 2025.

The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended March 31, 2025 by level within the fair value measurement hierarchy:

The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended December 31, 2024 by level within the fair value measurement hierarchy:

Our assets measured at fair value on a non-recurring basis are limited to loans classified as Watch List—Doubtful and other real estate owned. The tabular disclosures above include only those loans or other real estate owned that had a change in the provision for credit loss during the reporting period or for which a new specific provision for credit loss was established during the reporting period. The fair value of Watch List—Doubtful loans is derived in accordance with FASB ASC Subtopic 326-10, “Financial Instruments – Credit Losses - Overall”. They are primarily comprised of collateral-dependent commercial loans. As the primary sources of loan repayments decline, the secondary repayment source, the collateral, takes on greater significance. Correctly evaluating the fair value becomes even more important. Re-measurement of the loan to fair value is done through a specific valuation allowance included in the allowance for credit losses (“ACL”). The fair value of the loan is based on the fair value of the collateral, as determined through either an appraisal or internal evaluation process. The basis for our appraisal and appraisal review process are applicable regulatory guidelines, including regulatory appraisal laws and the Uniform Standards of Professional Appraisal Practice, which are incorporated into our lending policy. All collateral dependent loans are evaluated in accordance with our lending policy to assess if a third-party appraisal is required to be obtained as part of our credit underwriting and monitoring process. Collateral dependent loans that do not meet the requirements for a third-party appraisal are required to undergo an internal evaluation by our in-house independent appraisal staff.

Our determination to either seek an appraisal or to perform an internal evaluation is performed by our credit quality committee, which analyzes the existing collateral values of the doubtful loans and identifies obsolete appraisals or internal evaluations. The credit quality committee reviews the existing appraisal to determine if the collateral value is reasonable in view of the current use of the collateral and the economic environment related to the collateral. The

ultimate decision on the appropriate action is made by our independent credit administration team. A new appraisal is not required if an internal evaluation, as performed by our in-house independent appraisal staff, is able to appropriately update the original appraisal assumptions to reflect current market conditions and provide an estimate of the collateral’s market value for analysis of the doubtful loan. The internal evaluations must be in writing and contain sufficient information detailing the analysis, assumptions and conclusions, and they must support performing an evaluation in lieu of ordering a new appraisal.

As of March 31, 2025, we had $164,472,000 of doubtful commercial collateral-dependent loans, of which $107,692,000 had an appraisal performed within the immediately preceding rolling twelve-month period, and of which $0 had an internal evaluation performed within the immediately preceding rolling twelve-month period. As of December 31, 2024, we had approximately $168,621,000 of doubtful commercial collateral-dependent loans, of which $110,583,000 had an appraisal performed within the immediately preceding rolling twelve-month period and of which $0 had an internal evaluation performed within the immediately preceding rolling twelve-month period.

Other real estate owned is comprised of real estate acquired by foreclosure and deeds in lieu of foreclosure. Other real estate owned is carried at the lower of the recorded investment in the property or its fair value less estimated costs to sell such property (as determined by independent appraisal) within Level 3 of the fair value hierarchy. Prior to foreclosure, the value of the underlying loan is written down to the fair value of the real estate to be acquired by a charge to the ACL, if necessary. The fair value is reviewed periodically, and subsequent write-downs are made through a charge to operations, accordingly. Other real estate owned is included in other assets on the consolidated financial statements. For the three months ended March 31, 2025 and the twelve months ended December 31, 2024, we recorded $46,000 and $2,228,000, respectively, in charges to the ACL in connection with loans transferred to other real estate owned. For the three months ended March 31, 2025 and the twelve months ended December 31, 2024, we recorded $0 and $632,000, respectively, in adjustments to fair value in connection with other real estate owned.

The fair value estimates, methods, and assumptions for our financial instruments at March 31, 2025 and December 31, 2024 are outlined below.

Cash and Cash Equivalents

For these short-term instruments, the carrying amount is a reasonable estimate of fair value.

Time Deposits with Banks

The carrying amounts of time deposits with banks approximate fair value.

Investment Securities Held-to-Maturity

The carrying amounts of investments held-to-maturity approximate fair value.

Investment Securities

For investment securities, which include U.S. Treasury securities, obligations of other U.S. government agencies, obligations of states and political subdivisions and mortgage pass-through and related securities, fair values are established by an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. See disclosures of fair value of investment securities in Note 6.

Loans

Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are segregated by type, such as commercial, real estate or consumer loans, as outlined by regulatory reporting guidelines. Each category is segmented into fixed and variable interest rate terms and by performing and non-performing categories.

For variable rate performing loans, the carrying amount approximates fair value. For fixed-rate performing loans, except residential mortgage loans, the fair value is calculated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect the credit and interest rate risk inherent in the loan. For performing residential mortgage loans, fair value is estimated by discounting contractual cash flows adjusted for prepayment estimates using discount rates based on secondary market sources or the primary origination market. Fixed-rate performing loans are within Level 3 of the fair value hierarchy. At March 31, 2025 and December 31, 2024, the carrying amount of fixed rate performing loans was$1,257,044,000 and $1,216,156,000, respectively, and the estimated fair value was $1,171,394,000 and $1,154,862,000, respectively.

Accrued Interest

The carrying amounts of accrued interest approximate fair value.

Deposits

The fair value of deposits with no stated maturity, such as non-interest-bearing demand deposit accounts, savings accounts and interest-bearing demand deposit accounts, was equal to the amount payable on demand as of March 31, 2025 and December 31, 2024. The fair value of time deposits is based on the discounted value of contractual cashflows. The discount rate is based on currently offered rates. Time deposits are within Level 3 of the fair value hierarchy. At March 31, 2025 and December 31, 2024, the carrying amount of time deposits was $2,945,678,000 and $2,899,543,000, respectively, and the estimated fair value was $2,943,387,000 and $2,895,245,000, respectively.

Securities Sold Under Repurchase Agreements

Securities sold under repurchase agreements are short-term maturities. Due to the contractual terms of the instruments, the carrying amounts approximated fair value at March 31, 2025 and December 31, 2024.

Junior Subordinated Deferrable Interest Debentures

We currently have floating-rate junior subordinated deferrable interest debentures outstanding. Due to the contractual terms of the floating-rate junior subordinated deferrable interest debentures, the carrying amounts approximated fair value at March 31, 2025 and December 31, 2024.

Other Borrowed Funds

We currently have short- and long-term borrowings issued from the Federal Home Loan Bank (“FHLB”). Due to the contractual terms of the short-term borrowings, the carrying amounts approximated fair value at March 31, 2025. The long-term borrowings outstanding at March 31, 2025 and December 31, 2024 are fixed-rate borrowings and the fair value is based on established market spreads for similar types of borrowings. The fixed rate long-term borrowings are included in Level 2 of the fair value hierarchy. At March 31, 2025 and December 31, 2024, the carrying amount of the fixed rate long-term FHLB borrowings was$10,489,000 and $10,541,000, respectively, and the estimated fair value was $10,489,000 and $10,541,000, respectively.

Commitments to Extend Credit and Letters of Credit

Commitments to extend credit and fund letters of credit are principally at current interest rates, and, therefore, the carrying amount approximates fair value.

Limitations

Fair value estimates are made at a point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time our entire holdings of a particular financial instrument. Because no market exists for a significant portion of our financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments and other factors. These estimates are

subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Fair value estimates are based on existing on- and off-statement of condition financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. Other significant assets and liabilities that are not considered financial assets or liabilities include the bank premises and equipment and core deposit value. In addition, the tax ramifications related to the effect of fair value estimates have not been considered in the above estimates.

Note 3 — Loans

A summary of loans, by loan type, at March 31, 2025 and December 31, 2024 is as follows:

Note 4 — Allowance for Credit Losses

The ACL is based on a loss-rate methodology that measures lifetime losses on loan pools that have similar risk characteristics. Loans that do not have similar risk characteristics are evaluated on an individual basis. The segmentation of the loan portfolio into pools requires a balancing process between capturing similar risk characteristics and containing sufficient loss history to provide meaningful results. Our segmentation starts at the general loan category with further sub-segmentation based on collateral types that may be of meaningful size and/or may contain sufficient differences in risk characteristics based on management’s judgement that would warrant further segmentation. Risk management begins with a strong and conservative lending policy that specifies lending limits that are well below allowable regulatory limits, provides highly restrictive lending authority to lending officers, and promotes judicious lending terms and diversification. The general loan categories along with primary risk characteristics used in our calculation are as follows:

Commercial and industrial loans. This category includes loans extended to a diverse array of businesses for working capital or equipment purchases. These loans are mostly secured by the collateral pledged by a borrower that is directly related to the business activities of the borrower’s company such as equipment, accounts receivable and inventory. The borrower’s abilities to generate revenues from equipment purchases, collect accounts receivable, and turn inventory into sales are risk factors in the repayment of the loan. A small portion of this loan category is related to loans secured by oil and gas production and loans secured by aircraft.

Construction and land development loans. This category includes loans for the development of unimproved land to lot development for both residential and commercial use and vertical construction across residential and commercial real estate classes. These loans carry the risk of repayment when projects incur cost overruns, have an increase in the price of construction materials, encounter zoning, entitlement or environmental issues, or encounter other factors that may affect the completion of a project on time and on budget. Additionally, repayment risk may be negatively impacted when the market experiences a deterioration in the value of real estate. Risks specifically related to 1-4 family development loans also include mortgage rate risk and the practice by the mortgage industry of imposing more restrictive underwriting standards, which inhibits the buyer from obtaining long term financing, creating excessive housing and lot inventory in the market.

Commercial real estate loans. This category includes loans secured by farmland, multifamily properties, owner-occupied commercial properties, and non-owner-occupied commercial properties. Owner-occupied commercial properties include warehouses often along the U.S. border for import/export operations, office space where the

borrower is the primary tenant, restaurants and other single-tenant retail spaces. Non-owner-occupied commercial properties include hotels, retail centers, office and professional buildings, and leased warehouses. These loans carry the risk of repayment when market values deteriorate, the business experiences turnover in key management, the business is unable to attract or maintain stable occupancy levels, or the market experiences an exit of a specific business type that is significant to the local economy, such as a manufacturing plant. Our primary risk management tool is internal monitoring measured against internal concentration limits that are significantly lower than regulatory thresholds and are segmented by low-risk and high-risk characteristics, such as the borrower’s equity, cash flow coverage, and non-amortizing versus amortizing status, further disaggregated by the length of time to pay in full. This monitoring is regularly reported to senior management and the board of directors. Risk management practices also extend to managing the borrower’s relationship with us and are designed to recognize degradation in the borrower’s ability to repay under established terms well before the borrower may default. Loan and deposit activity by the borrower is monitored on a frequent basis, which may prompt a change in risk classification. Once a loan is moved to a more severe risk classification, the loan performance, and when applicable, a plan by the borrower to rectify issues are monitored and reviewed at least quarterly. Additionally, our credit administration team, who is independent from the lending team, reviews a substantial portion of the commercial lending portfolio annually, which includes a significant portion of the commercial real estate loan portfolio given the current mix of loans in our portfolio. The table below summarizes the commercial real estate loan portfolio disaggregated by the type of real estate securing the credit as of March 31, 2025 and December 31, 2024:

*1-4 family mortgages.*This category includes both first and second lien mortgages for the purposes of home purchases or refinancing existing mortgage loans. A small portion of this loan category is related to home equity lines of credits, lots purchases, and home construction. Loan repayments may be affected by unemployment or underemployment and deteriorating market values of real estate.

Consumer loans. This category includes deposit secured, vehicle secured, and unsecured loans, including overdrafts, made to individuals. Repayment is primarily affected by unemployment or underemployment.

The loan pools are further broken down using a risk-based segmentation based on internal classifications for commercial loans and past due status for consumer mortgage loans. Non-mortgage consumer loans are evaluated as one segment. On a weekly basis, commercial loan past due reports are reviewed by our credit quality committee to determine if a loan has any potential problems and should be placed on our internal Watch List report. Additionally, our credit department reviews the majority of our loans for proper internal classification purposes regardless of whether they are

past due and segregates any loans with potential problems for further review. The credit department will discuss the potential problem loans with the servicing loan officers to determine any relevant issues that were not discovered in the evaluation. Also, an analysis of loans that is provided through examinations by regulatory authorities is considered in the review process. After the above analysis is completed, we determine if a loan should be placed on our internal Watch List report because of issues related to the analysis of the credit, credit documents, collateral and/or payment history.

Our internal Watch List report is segregated into the following categories: (i) Pass, (ii) Economic Monitoring, (iii) Special Review, (iv) Watch List—Pass, (v) Watch List—Substandard, and (vi) Watch List—Doubtful. Loans placed in the Economic Monitoring or Special Review categories reflect our opinion that the loans have potential weaknesses that require monitoring on a more frequent basis. Credits in those categories are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted. Loans placed in the Watch List—Pass category reflect our opinion that the credit contains weaknesses that represent a greater degree of risk, which warrants “extra attention.” Credits placed in this category are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted. Loans placed in the Watch List—Substandard category are considered to be potentially inadequately protected by the current sound worth and debt service capacity of the borrower or of any pledged collateral. Those credit obligations, even if apparently protected by collateral value, have shown defined weaknesses related to adverse financial, managerial, economic, market, or political conditions which may jeopardize repayment of principal and interest under contractual terms. Furthermore, there is a possibility that we may sustain some future loss if such weaknesses are not corrected. Loans placed in the Watch List—Doubtful category have shown defined weaknesses and reflect our belief that it is likely, based on current information and events, that we will be unable to collect all principal and/or interest amounts contractually due. Loans placed in the Watch List—Doubtful category are placed on non-accrual when they are moved to that category.

For the purposes of the ACL, in order to maintain segments with sufficient history for meaningful results, the credits in the Pass and Economic Monitoring categories are aggregated, the credits in the Special Review and Watch List—Pass category are aggregated, and the credits in the Watch List—Substandard category remain in their own segment. For loans classified as Watch List—Doubtful, management evaluates these credits in accordance with FASB ASC Subtopic 326-20, “Financial Instruments – Credit Losses – Measured at Amortized Cost,” and, if deemed necessary, a specific reserve is allocated to the loan. The analysis of the specific reserve is based on a variety of factors, including the borrower’s ability to pay, the economic conditions impacting the borrower’s industry and any collateral deficiency. If it is a collateral-dependent loan, the net realizable fair value of collateral will be evaluated for any deficiencies. Substantially all of our loans evaluated as Watch List – Doubtful are measured using the fair value of collateral method. In rare cases, we may use other methods to determine the specific reserve of a loan if such loan is not collateral dependent.

Within each collectively evaluated pool, the robustness of the lifetime historical loss-rate is evaluated and, if needed, is supplemented with peer loss rates through a model risk adjustment. Certain qualitative loss factors are then evaluated to incorporate management’s two-year reasonable and supportable forecast period followed by a reversion to the pool’s average lifetime loss-rate. Those qualitative loss factors are: (i) trends in portfolio volume and composition, (ii) volume and trends in classified loans, delinquencies and non-accruals, (iii) concentration risk, (iv) trends in underlying collateral value, (v) changes in policies, procedures, and strategies, and (vi) economic conditions. Qualitative factors also include potential losses stemming from operational risk factors arising from fraud, natural disasters, pandemics, geopolitical events and large loans. The large loan operational risk factor was added to our ACL calculation beginning in the second quarter of 2023. Because of the magnitude of large loans, they pose a higher risk of default. Recognizing this risk and establishing an operational risk factor to capture that risk, is prudent action in the current economic environment. Large loans are usually part of a larger relationship with collateral that is pledged across the relationship. Defaulting on a larger loan may therefore jeopardize an entire collateral relationship. The current economic environment has created challenges for borrowers to service their debt. Increasing capitalization rates, elevated office vacancies, an upward trend in apartment vacancies and significant increases in interest rates are all contributing to the elevated risk in large loans. Should any of the factors considered by management in evaluating the adequacy of the ACL change, our estimate could also change, which could affect the level of future credit loss expense.

We have elected to not measure an ACL for accrued interest receivable given our timely approach in identifying and writing off uncollectible accrued interest. An ACL for off-balance sheet exposure is derived from a projected usage rate of any unfunded commitment multiplied by the historical loss-rate, plus model risk adjustment, if any, of the on-balance sheet loan pools.

Our management continually reviews the ACL of the Subsidiary Banks using the amounts determined from the estimates established on specific doubtful loans, the estimate established on quantitative historical loss percentages, and the estimate based on qualitative current conditions and reasonable and supportable two-year forecasted data. Our methodology reverts to the average lifetime loss-rate beyond the forecast period when we can no longer develop reasonable and supportable forecasts. Should any of the factors considered by management in evaluating the adequacy of the estimate for current expected credit losses change, our estimate of current expected credit losses could also change, which could affect the level of future credit loss expense. While the calculation of our ACL utilizes management’s best judgment and all information reasonably available, the adequacy of the ACL is dependent on a variety of factors beyond our control, including, among other things, the performance of the entire loan portfolio, the economy, government actions, changes in interest rates, and the view of regulatory authorities towards loan classifications.

A summary of the transactions in the allowance for credit loan losses by loan class is as follows:

The increase in losses charged to the ACL for the three months ended March 31, 2024 in the Commercial category can be attributed to a charge-down on one loan secured primarily by equipment and pipeline infrastructure used in the oil and gas industry. The credit has been classified as Watch List—Doubtful since the end of 2022 at which time, and going forward, we have evaluated our loss exposure and adjusted reserves accordingly. We also continued to attempt to work with our customer during that period; however, those negotiations came to a halt late in the third quarter of 2023 when the customer declared bankruptcy. In March 2024, the bankruptcy court awarded the winning bid at foreclosure for the assets collateralizing the loan to a principal owner of the business. The bid was not for the full carrying value of the loan and resulted in a charge-down of approximately$25.6 million. We expect to recover a portion of the charge-down by pursuing repayment from the guarantor of the credit through a binding arbitration process. No changes to the qualitative loss factors were made for the March 31, 2025 ACL.

The tables below provide additional information on the balance of loans individually or collectively evaluated for impairment and their related allowance, by loan class, as of March 31, 2025 and December 31, 2024:

The table below provides additional information on loans accounted for on a non-accrual basis by loan class at March 31, 2025 and December 31, 2024:

We occasionally provide modifications to borrowers experiencing financial difficulties. Modifications may include certain concessions that we must evaluate under current accounting standards to determine the need for disclosure. Concessions to borrowers experiencing financial difficulties that would require disclosure include principal forgiveness, a term extension, an other-than-insignificant payment delay, an interest rate reduction or a combination of these concessions. For the three months ended March 31, 2025, we did not provide any modifications under these circumstances to any borrower experiencing financial difficulty.

The Subsidiary Banks charge-off that portion of any loan that management considers to represent a loss or that is classified as a “loss” by bank examiners. Management generally considers commercial and industrial or real estate loans to represent a loss, in whole or part, when an exposure beyond any collateral coverage is apparent and when no further collection of the loss portion is anticipated based on the borrower’s financial condition and general economic conditions in the borrower’s industry. Generally, unsecured consumer loans are charged-off when 90 days past due.

While our management believes that it is generally able to identify borrowers with financial problems reasonably early and to monitor credit extended to such borrowers carefully, there is no precise method of predicting loan losses. The determination that a loan is likely to be uncollectible and that it should be wholly or partially charged-off as a loss is an exercise of judgment. Similarly, the determination of the adequacy of the ACL can be made only on a subjective basis. It is the judgment of our management that the ACL at March 31, 2025 was adequate to absorb probable losses from loans in the portfolio at that date.

The following tables present information regarding the aging of past due loans by loan class at March 31, 2025 and December 31, 2024:

The increase in Commercial loans past due 90 days or more can be attributed totwo loans secured by commercial properties that were placed on non-accrual in the fourth quarter of 2024 and are more than 90 days past due. Thetwo loans were past due less than 90 days at December 31, 2024 as reflected in the table above. The decrease in commercial real estate: multifamily loans past due 90 days or greater can be primarily attributed totwo loans secured by apartments that are on non-accrual that were brought current during the non-accrual period.

A summary of the loan portfolio by credit quality indicator by loan class and by year of origination at March 31, 2025 and December 31, 2024 is presented below:

The decrease in Watch List – Substandard Commercial real estate: farmland & commercial loans at March 31, 2025 can be primarily attributed to a change in classification ontwo loans in one relationship secured by hotels. The loans were upgraded to Special Review during the first quarter of 2025.

** Note 5 — Stock Options**

On April 5, 2012, our Board of Directors (the “Board”) adopted the 2012 International Bancshares Corporation Stock Option Plan (the “2012 Plan”). There were 800,000 shares of common stock available for stock option grants under the 2012 Plan, which were qualified incentive stock options (“ISOs”) or non-qualified stock options. Options granted may be exercisable for a period of up to 10 years from the date of grant, excluding ISOs granted to 10% shareholders, which may be exercisable for a period of up to only five years. On April 4, 2022, the 2012 Plan expired and was not renewed.

A summary of option activity under the 2012 Plan for the three months ended March 31, 2025 is as follows:

Stock-based compensation expense included in the consolidated statements of income for the three months ended March 31, 2025 was $45,000. Stock-based compensation expense included in the consolidated statements of income for the three months ended March 31, 2024 was $74,000. As of March 31, 2025, there was approximately $173,000 of total unrecognized stock-based compensation cost related to non-vested options granted under our plans that will be recognized over a weighted average period of 1.4 years.

On April 18, 2022, the Board adopted the 2022 International Bancshares Corporation Stock Appreciation Rights Plan (the “SAR Plan”). There are 750,000 shares of underlying common stock that may be used for stock appreciation right (“SAR”) grants under the SAR Plan, however, no actual shares will be granted. Upon exercise, the SAR will be settled in cash. SARs granted may be exercisable for a period of up to 10 years from the date of grant and may vest over aneight-year period. As of March 31, 2025, a total of 452,127 SARs had been issued under the SAR Plan.

A summary of activity under the SAR Plan for the three months ended March 31, 2025 is as follows:

The fair value of the liability for payments due to SAR holders at March 31, 2025 and December 31, 2024 is approximately $4,924,000 and $4,540,000, respectively, as calculated using a Black-Sholes-Merton pricing model, and is

included in other liabilities on the consolidated statements of condition. The expense recorded in connection with all grants under the SAR Plan totaled $388,000 for the three months ended March 31, 2025. The expense recorded in connection with all grants under the SAR Plan totaled $1,080,000 for the three months ended March 31, 2024. As of March 31, 2025, there was approximately $7,826,000 in unrecognized liability related to non-vested SARs granted under the SAR Plan that will be recognized over a weighted average period of 7.3 years.

** Note 6 — Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments**

We classify debt securities into one of three categories: held-to-maturity, available-for-sale, or trading. Such debt securities are reassessed for appropriate classification at each reporting date. Securities classified as “held-to-maturity” are carried at amortized cost for financial statement reporting, while securities classified as “available-for-sale” and “trading” are carried at their fair value. Unrealized holding gains and losses are included in net income for those securities classified as “trading,” while unrealized holding gains and losses related to those securities classified as “available-for-sale” are excluded from net income and reported net of tax as other comprehensive income (loss) and accumulated other comprehensive income (loss) until realized, or in the case of losses, when deemed other than temporary. Available-for-sale and held-to-maturity debt securities in an unrealized loss position are evaluated for the underlying cause of the loss. In the event that the deterioration in value is attributable to credit related reasons, then the amount of credit-related impairment will be recorded as a charge to our ACL with subsequent changes in the amount of impairment, up or down, also recorded through our ACL. We have evaluated the debt securities classified as available-for-sale and held-to-maturity at March 31, 2025 and have determined that no debt securities in an unrealized loss position are arising from credit related reasons and have therefore not recorded any allowances for debt securities in our ACL for the period. Unrealized gains and losses related to equity securities with readily determinable fair values are included in net income.

The amortized cost and estimated fair value by type of investment security at March 31, 2025 are as follows:

The amortized cost and estimated fair value by type of investment security at December 31, 2024 are as follows:

The amortized cost and estimated fair value of investment securities at March 31, 2025, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties.

Residential mortgage-backed securities are securities primarily issued by the Federal Home Loan Mortgage Corporation (“Freddie Mac”), Federal National Mortgage Association (“Fannie Mae”), or the Government National Mortgage Association (“Ginnie Mae”). Investments in residential mortgage-backed securities issued by Ginnie Mae are fully guaranteed by the U.S. Government. Investments in residential mortgage-backed securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. Government, however, we believe that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in early September 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae or Freddie Mac are rated consistently as AAA rated securities.

The amortized cost and fair value of available-for-sale debt investment securities pledged to qualify for fiduciary powers, to secure public monies as required by law, repurchase agreements and short-term fixed borrowings was $1,854,987,000 and $1,630,062,000, respectively, at March 31, 2025.

Proceeds from the sales and calls of available-for-sale debt securities were $3,505,000 for the three months ended March 31, 2025, which included $0 of mortgage-backed securities. Gross gains of $0 and gross losses of $0 were realized on the sales and calls for the three months ended March 31, 2025. Proceeds from the sales and calls of available-for-sale debt securities were$1,720,000 for the three months ended March 31, 2024 which included $0 of

mortgage-backed securities. Gross gains of$0 and gross losses of $0 were realized on the sales and calls for the three months ended March 31, 2024.

Gross unrealized losses on debt investment securities and the fair value of those related securities, aggregated by investment category and length of time that individual debt securities have been in a continuous unrealized loss position at March 31, 2025, were as follows: