Form 8-K

8-K — SOUTHSIDE BANCSHARES INC

Accession: 0000705432-26-000103

Filed: 2026-07-24

Period: 2026-07-24

CIK: 0000705432

SIC: 6022 (STATE COMMERCIAL BANKS)

Item: Results of Operations and Financial Condition

Item: Financial Statements and Exhibits

Documents

8-K — sbsi-20260724.htm (Primary)

EX-99.1 (ex991er06302026.htm)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K

8-K (Primary)

Filename: sbsi-20260724.htm · Sequence: 1

sbsi-20260724

0000705432falseNYSETX00007054322026-07-242026-07-240000705432exch:XCHI2026-07-242026-07-240000705432exch:XNYS2026-07-242026-07-24

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

July 24, 2026

Date of Report (Date of earliest event reported)

Southside Bancshares, Inc.

(Exact Name of Registrant as Specified in its Charter)

Texas 001-42396 75-1848732

(State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS Employer Identification No.)

1201 S. Beckham Avenue, Tyler, TX 75701

(Address of Principal Executive Offices) (Zip Code)

Registrant's telephone number, including area code: (903) 531-7111

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities Registered Pursuant to Section 12(b) of the Act:

Title of each class Trading Symbol Name of each exchange on which registered

Common stock, $1.25 par value SBSI New York Stock Exchange

NYSE Texas

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

☐

ITEM 2.02. RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

On July 24, 2026, Southside Bancshares, Inc. issued a press release announcing its financial results for the second quarter ended June 30, 2026. A copy of the press release is attached as Exhibit 99.1 hereto and is hereby incorporated herein by reference.

The information in this Current Report on Form 8-K, including the attached exhibit, is being furnished as provided in General Instruction B.2 to Form 8-K, to the Securities and Exchange Commission and shall not be deemed to be “filed” for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section. Furthermore the information contained in this Current Report on Form 8-K shall not be deemed to be incorporated by reference in any filing with the Securities and Exchange Commission, except as shall be expressly provided by specific reference in such filing.

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS

(D)Exhibits. The following materials are furnished as exhibits to this Current Report on Form 8-K:

Exhibit

Number

Description of Exhibit

99.1

Press release dated July 24, 2026

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Southside Bancshares, Inc.

Date: July 24, 2026 By: /s/ JULIE N. SHAMBURGER

Julie N. Shamburger, CPA

Chief Financial Officer

(Principal Financial Officer)

EX-99.1

Filename: ex991er06302026.htm · Sequence: 2

Document

EXHIBIT 99.1

SOUTHSIDE BANCSHARES, INC.

ANNOUNCES FINANCIAL RESULTS FOR THE

SECOND QUARTER ENDED JUNE 30, 2026

•Second quarter net income of $26.8 million;

•Second quarter earnings per diluted common share of $0.90;

•Annualized return on second quarter average assets of 1.23%;

•Annualized return on second quarter average shareholders’ equity of 12.33% and average tangible common equity(1) of 16.09%; and

•Nonperforming assets remain low at 0.11% of total assets.

Tyler, Texas (July 24, 2026) Southside Bancshares, Inc. (“Southside” or the “Company”) (NYSE: SBSI) today reported its financial results for the quarter ended June 30, 2026.

“We are pleased to report solid financial results for the second quarter ended June 30, 2026, which include earnings per share of $0.90, a return on average assets of 1.23% and a return on average tangible common equity of 16.09%,” stated Keith Donahoe, President and Chief Executive Officer of Southside. “We recorded an increase in noninterest income and a decrease in noninterest expense, resulting in an increase in linked quarter net income of $3.6 million, or 15.4%. Linked quarter funding costs increased resulting in a decrease in net interest income of $355,000 to $57.3 million. Asset quality metrics remain solid with the nonperforming assets to total assets ratio at 0.11%. Although linked quarter loan growth was modest at $3.4 million, we had strong production during the quarter and expect to meet our mid-single digit loan growth for the year.”

Operating Results for the Three Months Ended June 30, 2026

Net income was $26.8 million for the three months ended June 30, 2026, compared to $21.8 million for the same period in 2025, an increase of $5.0 million, or 23.0%. Earnings per diluted common share were $0.90 for the three months ended June 30, 2026, compared to $0.72 for the same period in 2025, an increase of $0.18, or 25.0%. The increase in net income was due to increases in net interest income and noninterest income and decreases in noninterest expense and provision for credit losses, partially offset by an increase in income tax expense. Annualized returns on average assets and average shareholders’ equity for the three months ended June 30, 2026 were 1.23% and 12.33%, respectively, compared to 1.07% and 10.73%, respectively, for the three months ended June 30, 2025. Our efficiency ratio and tax-equivalent efficiency ratio(1) were 54.42% and 52.96%, respectively, for the three months ended June 30, 2026, compared to 55.67% and 53.70%, respectively, for the three months ended June 30, 2025, and 56.44% and 54.98%, respectively, for the three months ended March 31, 2026.

Net interest income for the three months ended June 30, 2026 was $57.3 million, an increase of $3.1 million, or 5.7%, compared to the same period in 2025. The increase in net interest income was primarily due to an increase in average balance of our interest earning assets and a decrease in the average rate paid on our interest bearing liabilities, partially offset by an increase in the average balance and mix of our interest bearing liabilities and a decrease in the average yield of our interest earning assets. Linked quarter, net interest income decreased $0.4 million, or 0.6%, compared to $57.7 million for the three months ended March 31, 2026, due to an increase in the average balance and mix of our of interest bearing liabilities and a decrease in the average yield of our interest earning assets, partially offset by an increase in the average balance of our interest earning assets.

Our net interest margin and tax-equivalent net interest margin(1) decreased to 2.80% and 2.90%, respectively, for the three months ended June 30, 2026, compared to 2.91% and 3.01%, respectively, for the three months ended March 31, 2026, and from 2.82% and 2.95%, respectively, for the same period in 2025.

Noninterest income was $14.0 million for the three months ended June 30, 2026, an increase of $1.9 million, or 15.3%, compared to $12.1 million for the same period in 2025, due to increases in bank owned life insurance (“BOLI”) income, trust fees, other noninterest income, deposit services and brokerage services income. On a linked quarter basis, noninterest income increased $1.4 million, or 11.2%, compared to the three months ended March 31, 2026, primarily due to increases in BOLI income, deposit services, other noninterest income and trust fees during the three months ended June 30, 2026.

Noninterest expense decreased $0.6 million, or 1.5%, to $38.7 million for the three months ended June 30, 2026, compared to $39.3 million for the same period in 2025, primarily due to a decrease in other noninterest expense, partially offset by increases in salaries and employee benefits and professional fees. On a linked quarter basis, noninterest expense decreased by $1.9

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million, or 4.7%, compared to the three months ended March 31, 2026. The decrease was due to decreases in salaries and employee benefits expense and loss on redemption of subordinated notes.

Income tax expense increased $1.0 million, or 21.7%, for the three months ended June 30, 2026, compared to the same period in 2025. On a linked quarter basis, income tax expense increased $0.7 million, or 13.9%. Our effective tax rate (“ETR”) decreased slightly to 17.6% for the three months ended June 30, 2026, compared to 17.8% for both of the three-month periods ended June 30, 2025 and March 31, 2026. The marginally lower ETR for the three months ended June 30, 2026 compared to the same period in 2025 and the three months ended March 31, 2026, was partially due to a decrease in state income tax expense as a percentage of pre-tax income as well as a discrete tax benefit recorded in connection with equity award transactions.

Operating Results for the Six Months Ended June 30, 2026

Net income was $50.1 million for the six months ended June 30, 2026, compared to $43.3 million for the same period in 2025, an increase of $6.8 million, or 15.6%. Earnings per diluted common share were $1.68 for the six months ended June 30, 2026, compared to $1.42 for the same period in 2025, an increase of $0.26, or 18.3%. The increase in net income was due to increases in net interest income and noninterest income, partially offset by increases in noninterest expense, income tax expense and provision for credit losses. Returns on average assets and average shareholders’ equity for the six months ended June 30, 2026 were 1.16% and 11.65%, respectively, compared to 1.05% and 10.65%, respectively, for the six months ended June 30, 2025. Our efficiency ratio and tax-equivalent efficiency ratio(1) were 55.43% and 53.97%, respectively, for the six months ended June 30, 2026, compared to 56.34% and 54.36%, respectively, for the six months ended June 30, 2025.

Net interest income was $115.0 million for the six months ended June 30, 2026, compared to $108.1 million for the same period in 2025, an increase of $6.9 million, or 6.4%, due to an increase in the average balance of our interest earning assets and a decrease in the average rate paid on our interest bearing liabilities, partially offset by a decrease in the yield on our interest earning assets and an increase in the average balance and mix of our interest bearing liabilities.

Our net interest margin and tax-equivalent net interest margin(1) increased to 2.86% and 2.95%, respectively, for the six months ended June 30, 2026, compared to 2.78% and 2.91%, respectively, for the same period in 2025.

Noninterest income was $26.6 million for the six months ended June 30, 2026, compared to $22.4 million for the same period in 2025, an increase of $4.2 million, or 18.9%. There were increases to all noninterest income categories, however, the primary increases occurred in other noninterest income, trust fees, BOLI income and a decrease in net loss on sale of securities available for sale (“AFS”) securities.

Noninterest expense was $79.3 million for the six months ended June 30, 2026, compared to $76.3 million for the same period in 2025, an increase of $2.9 million, or 3.8%. The increase was primarily due to increases in salaries and employee benefits expense and loss on redemption of subordinated notes, partially offset by a decrease in other noninterest expense.

Income tax expense increased $1.3 million, or 14.2%, for the six months ended June 30, 2026, compared to the same period in 2025. Our ETR was approximately 17.7% and 17.9% for the six months ended June 30, 2026 and 2025, respectively. The marginally lower ETR for the six months ended June 30, 2026, as compared to the same period in 2025, was partially due to a decrease in state income tax expense as a percentage of pre-tax income as well as a discrete tax benefit recorded in connection with equity award transactions.

Balance Sheet Data

At June 30, 2026, Southside had $8.76 billion in total assets, compared to $8.51 billion at December 31, 2025 and $8.34 billion at June 30, 2025.

Loans at June 30, 2026 were $4.95 billion, an increase of $347.6 million, or 7.6%, compared to $4.60 billion at June 30, 2025. Linked quarter, loans increased $3.4 million, or 0.1%, due to increases of $21.5 million in commercial owner-occupied loans, $20.5 million in municipal loans and $10.6 million in commercial loans. These increases were partially offset by decreases of $41.7 million in construction loans, $4.0 million in commercial real estate loans, $2.3 million in loans to individuals and $1.2 million in 1-4 family residential loans.

Securities at June 30, 2026 were $2.78 billion, an increase of $51.7 million, or 1.9%, compared to $2.73 billion at June 30, 2025. Linked quarter, securities decreased $86.3 million, or 3.0%, from $2.87 billion at March 31, 2026.

Deposits at June 30, 2026 were $6.17 billion, a decrease of $462.6 million, or 7.0%, compared to $6.63 billion at June 30, 2025, primarily due to a decrease of $602.1 million in brokered deposits and a decrease of $49.9 million in public funds deposits, offset by an increase of $189.4 million in retail deposits. Linked quarter, deposits decreased $705.1 million, or 10.3%, compared to $6.87 billion at March 31, 2026, primarily due to a decrease in brokered deposits of $777.9 million, or 99.4%, and a decrease in public fund deposits of $20.7 million, or 1.8%, partially offset by an increase in commercial and retail deposits of $93.5 million, or 1.9%.

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At June 30, 2026, we had 178,853 total deposit accounts with an average balance of $34,000. Our estimated uninsured deposits were 42.8% of total deposits as of June 30, 2026. When excluding affiliate deposits (Southside-owned deposits) and public fund deposits (all collateralized), our total estimated deposits without insurance or collateral was 24.9% as of June 30, 2026. Our noninterest bearing deposits represent approximately 22.8% of total deposits. Linked quarter, our cost of interest bearing deposits decreased 16 basis points from 2.65% in the prior quarter to 2.49%. Linked quarter, our cost of total deposits decreased 19 basis points from 2.13% in the prior quarter to 1.94%.

Our cost of interest bearing deposits decreased 26 basis points, from 2.83% for the six months ended June 30, 2025, to 2.57% for the six months ended June 30, 2026. Our cost of total deposits decreased 22 basis points, from 2.26% for the six months ended June 30, 2025, to 2.04% for the six months ended June 30, 2026.

Capital Resources and Liquidity

Our capital ratios and contingent liquidity sources remain solid. During the second quarter ended June 30, 2026, we did not repurchase any common stock, pursuant to our Stock Repurchase Plan (the “Plan”). Under the Plan, repurchases of our outstanding common stock may be carried out in open market purchases, privately negotiated transactions or pursuant to any trading plan that might be adopted in accordance with Rule 10b5-1 of The Securities Exchange Act of 1934, as amended. The Company has no obligation to repurchase any shares under the Plan and may modify, suspend or discontinue the Plan at any time. As of June 30, 2026, approximately 0.8 million authorized shares remained available for repurchase pursuant to the Plan. We have not repurchased any common stock pursuant to the Plan subsequent to June 30, 2026.

As of June 30, 2026, our total available contingent liquidity, net of current outstanding borrowings, was $1.99 billion, consisting of FHLB advances, Federal Reserve Discount Window and correspondent bank lines of credit.

Asset Quality

Nonperforming assets at June 30, 2026 were $9.8 million, or 0.11% of total assets, an increase of $0.1 million, or 0.7%, from $9.7 million, or 0.11% of total assets, at March 31, 2026. Nonperforming assets decreased $23.1 million, or 70.2%, compared to $32.9 million, or 0.39% of total assets, at June 30, 2025, due primarily to a decrease of $27.5 million in restructured loans. The decrease in restructured loans was due to the payoff of a $27.5 million restructured commercial real estate loan in the first quarter that was originally restructured with an extension of maturity in the first quarter of 2025 to allow for an extended lease up period. Classified loans totaled $260.1 million on June 30, 2026, compared to $290.8 million at March 31, 2026 and $176.9 million at December 31, 2025.

The allowance for loan losses totaled $45.6 million, or 0.92% of total loans, at June 30, 2026, compared to $46.0 million, or 0.93% of total loans, at March 31, 2026. The allowance for loan losses was $44.4 million, or 0.97% of total loans, at June 30, 2025. The decrease in allowance as a percentage of total loans compared to June 30, 2025 was primarily due to a decrease in multifamily construction loans as well as a reduction in reserves on individually evaluated loans.

For the three months ended June 30, 2026, we recorded a reversal of provision for credit losses for loans of $24,000, compared to a provision for credit losses of $0.7 million and $1.0 million for the three months ended June 30, 2025 and March 31, 2026, respectively. Net charge-offs were $0.3 million for the three months ended June 30, 2026, compared to net charge-offs of $0.9 million and $0.2 million for the three months ended June 30, 2025 and March 31, 2026, respectively. We recorded a provision for credit losses for loans of $1.0 million and $0.7 million for the six months ended June 30, 2026 and 2025, respectively. Net charge-offs were $0.5 million for the six months ended June 30, 2026, compared to net charge-offs of $1.2 million for the six months ended June 30, 2025.

We recorded a provision for credit losses on off-balance-sheet credit exposures of $0.1 million for the three months ended June 30, 2026, compared to a reversal of $19,000 and provision of $0.4 million for the three months ended June 30, 2025 and March 31, 2026, respectively. The balance of the allowance for off-balance-sheet credit exposures was $3.7 million and $3.8 million at June 30, 2026 and 2025, respectively, and is included in other liabilities. We recorded a provision for credit losses for off-balance-sheet credit exposures of $0.5 million and $0.6 million for the six months ended June 30, 2026 and 2025, respectively.

Dividend

Southside Bancshares, Inc. declared a second quarter cash dividend of $0.36 per share on May 6, 2026, which was paid on June 1, 2026, to all shareholders of record as of May 18, 2026.

_______________

(1) Refer to “Non-GAAP Financial Measures” below and to “Non-GAAP Reconciliation” at the end of the financial statement tables in this Earnings Release for more information and for a reconciliation of this non-GAAP financial measure to the nearest GAAP financial measure.

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Conference Call

Southside's management team will host a conference call to discuss its second quarter ended June 30, 2026 financial results on Friday, July 24, 2026 at 11:00 a.m. CDT. The conference call can be accessed by webcast, for listen-only mode, on the company website, https://investors.southside.com, under Events.

Those interested in participating in the question and answer session, or others who prefer to call-in, can register at https://events.q4inc.com/analyst/842475033?pwd=7c9ZzbJF to receive the dial-in number and unique code to access the conference call seamlessly. While not required, it is recommended that those wishing to participate, register 10 minutes prior to the conference call to ensure a more efficient registration process.

For those unable to attend the live event, a webcast recording will be available on the company website, https://investors.southside.com, for at least 30 days, beginning approximately two hours following the conference call.

Non-GAAP Financial Measures

Our accounting and reporting policies conform to generally accepted accounting principles (“GAAP”) in the United States and prevailing practices in the banking industry. However, certain non-GAAP measures are used by management to supplement the evaluation of our performance. These include return on average tangible common equity and the following fully taxable-equivalent measures (“FTE”): (i) Net interest income (FTE), (ii) net interest margin (FTE), (iii) net interest spread (FTE), and (iv) efficiency ratio (FTE), which include the effects of taxable-equivalent adjustments using a federal income tax rate of 21% to increase tax-exempt interest income to a tax-equivalent basis. Interest income earned on certain assets is completely or partially exempt from federal income tax. As such, these tax-exempt instruments typically yield lower returns than taxable investments.

Return on average tangible common equity. Return on average tangible common equity is a non-GAAP measure that calculates the return available to common shareholders without the impact of intangible assets and their related amortization, thereby allowing management to evaluate the performance of the business consistently.

Net interest income (FTE), net interest margin (FTE) and net interest spread (FTE). Net interest income (FTE) is a non-GAAP measure that adjusts for the tax-favored status of net interest income from certain loans and investments and is not permitted under GAAP in the consolidated statements of income. We believe that this measure is the preferred industry measurement of net interest income and that it enhances comparability of net interest income arising from taxable and tax-exempt sources. The most directly comparable financial measure calculated in accordance with GAAP is our net interest income. Net interest margin (FTE) is the ratio of net interest income (FTE) to average earning assets. The most directly comparable financial measure calculated in accordance with GAAP is our net interest margin. Net interest spread (FTE) is the difference in the average yield on average earning assets on a tax-equivalent basis and the average rate paid on average interest bearing liabilities. The most directly comparable financial measure calculated in accordance with GAAP is our net interest spread.

Efficiency ratio (FTE). The efficiency ratio (FTE) is a non-GAAP measure that provides a measure of productivity in the banking industry. This ratio is calculated to measure the cost of generating one dollar of revenue. The ratio is designed to reflect the percentage of one dollar which must be expended to generate that dollar of revenue. We calculate this ratio by dividing noninterest expense, excluding amortization expense on intangibles and certain nonrecurring expense by the sum of net interest income (FTE) and noninterest income, excluding net gain (loss) on sale of securities available for sale and certain nonrecurring impairments. The most directly comparable financial measure calculated in accordance with GAAP is our efficiency ratio.

These non-GAAP financial measures should not be considered alternatives to GAAP-basis financial statements and other bank holding companies may define or calculate these non-GAAP measures or similar measures differently. Whenever we present a non-GAAP financial measure in an SEC filing, we are also required to present the most directly comparable financial measure calculated and presented in accordance with GAAP and reconcile the differences between the non-GAAP financial measure and such comparable GAAP measure.

Management believes that (i) adjusting return on average shareholders’ equity for the impact of intangible assets and their related amortization and (ii) adjusting net interest income, net interest margin and net interest spread to a fully taxable-equivalent basis are standard practices in the banking industry as these measures provide useful information to make peer comparisons. Tax-equivalent adjustments are reflected in the respective earning asset categories as listed in the “Average Balances with Average Yields and Rates” tables.

A reconciliation of our non-GAAP financial measures to the comparable GAAP financial measures is included at the end of the financial statement tables.

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About Southside Bancshares, Inc.

Southside Bancshares, Inc. is a bank holding company with approximately $8.76 billion in assets as of June 30, 2026, that owns 100% of Southside Bank. Southside Bank currently has 55 branches in Texas and operates a network of 71 ATMs/ITMs.

To learn more about Southside Bancshares, Inc., please visit our investor relations website at https://investors.southside.com. Our investor relations site provides a detailed overview of our activities, financial information and historical stock price data. To receive email notification of company news, events and stock activity, please register on the website under Resources and Investor Email Alerts. Questions or comments may be directed to Lindsey Bailes at (903) 630-7965, or lindsey.bailes@southside.com.

Forward-Looking Statements

Certain statements of other than historical fact that are contained in this press release and in other written materials, documents and oral statements issued by or on behalf of the Company may be considered to be “forward-looking statements” within the meaning of and subject to the safe harbor protections of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are not guarantees of future performance, nor should they be relied upon as representing management’s views as of any subsequent date. These statements may include words such as “expect,” “estimate,” “project,” “anticipate,” “appear,” “believe,” “could,” “should,” “may,” “might,” “will,” “would,” “seek,” “intend,” “probability,” “risk,” “goal,” “target,” “objective,” “plans,” “potential,” and similar expressions. Forward-looking statements are statements with respect to the Company’s beliefs, plans, expectations, objectives, goals, anticipations, assumptions, estimates, intentions and future performance and are subject to significant known and unknown risks and uncertainties, which could cause the Company's actual results to differ materially from the results discussed in the forward-looking statements. For example, trends in asset quality, capital, liquidity, the Company's ability to sell nonperforming assets, expense reductions, planned operational efficiencies and earnings from growth and certain market risk disclosures, including the impact of interest rates and our expectations regarding rate changes, tax reform, inflation, tariffs, the impacts related to or resulting from other economic factors are based upon information presently available to management and are dependent on choices about key model characteristics and assumptions and are subject to various limitations. By their nature, certain of the market risk disclosures are only estimates and could be materially different from what actually occurs in the future. Accordingly, our results could materially differ from those that have been estimated. The most significant factors that could cause future results to differ materially from those anticipated by our forward-looking statements include: general economic conditions in our markets, including the ongoing impact of higher inflation levels, including higher energy and gas prices, interest rate fluctuations, including the impact of changes in interest rates on our financial projections, models and guidance, as well as the effects of declines in the real estate market, tariffs or trade wars (including reduced consumer spending, lower economic growth or recession, reduced demand for U.S. exports, disruptions to supply chains, and decreased demand for other banking products and services), high unemployment and increasing insurance costs, as well as the financial stress to borrowers as a result of the foregoing, all of which could impact economic growth and could cause a reduction in financial transactions and business activities, including decreased deposits and reduced loan originations, and our ability to manage liquidity in a rapidly changing and unpredictable market; the extensive regulations the Company is subject to and legislative and regulatory changes; the Company’s ability to successfully execute its business strategy; including risks related to potential acquisitions; the Company’s ability to innovate, to anticipate the needs of our current and future customers and to manage increased or expanded competition from banks and other financial service providers in its markets; the Company’s ability to effectively manage information technology systems, including third party vendors, cyber or data privacy incidents or other failures, outages, disruptions or security breaches; the Company’s ability to use technology to provide products and services to its customers, including the use of artificial intelligence, adverse developments in the banking industry and the potential impact of such developments on customer confidence, liquidity and regulatory responses to these developments, including in the context of regulatory examinations and related findings and actions; negative press and social media attention with respect to the banking industry or the Company, in particular; claims, litigation or regulatory investigations and actions that the Company may become subject to; the failure to identify, attract and retain key personnel and other employees and to engage in adequate succession planning; the Company’s recent executive transition; and the additional risks included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, under “Part I - Item 1. Forward Looking Information” and “Part I - Item 1A. Risk Factors” and in the Company’s other filings with the Securities and Exchange Commission. The Company disclaims any obligation to update any factors or to announce publicly the result of revisions to any of the forward-looking statements included herein to reflect future events or developments.

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Southside Bancshares, Inc.

Consolidated Financial Summary (Unaudited)

(Dollars in thousands)

As of

2026 2025

Jun 30, Mar 31, Dec 31, Sep 30, Jun 30,

ASSETS

Cash and due from banks $ 74,731 $ 72,997 $ 81,080 $ 90,519 $ 109,669

Interest earning deposits 301,916 296,986 302,906 365,263 260,357

Federal funds sold 20,609 17,490 5,800 11,130 20,069

Securities available for sale, at estimated fair value 1,569,836 1,647,379 1,456,219 1,292,431 1,457,124

Securities held to maturity, at net carrying value 1,211,900 1,220,641 1,247,477 1,263,401 1,272,906

Total securities 2,781,736 2,868,020 2,703,696 2,555,832 2,730,030

Federal Home Loan Bank stock, at cost 45,277 16,372 14,062 9,359 24,384

Loans held for sale 341 1,478 1,332 497 428

Loans 4,949,567 4,946,161 4,817,991 4,765,289 4,601,933

Less: Allowance for loan losses

(45,595) (45,963) (45,100) (45,294) (44,421)

Net loans 4,903,972 4,900,198 4,772,891 4,719,995 4,557,512

Premises & equipment, net 156,885 154,318 152,293 147,187 147,263

Goodwill 201,116 201,116 201,116 201,116 201,116

Other intangible assets, net 759 880 1,012 1,161 1,333

Bank owned life insurance 146,263 145,991 145,125 139,697 138,826

Other assets 130,109 126,336 133,277 141,404 148,979

Total assets $ 8,763,714 $ 8,802,182 $ 8,514,590 $ 8,383,160 $ 8,339,966

LIABILITIES AND SHAREHOLDERS' EQUITY

Noninterest bearing deposits $ 1,406,487 $ 1,374,190 $ 1,433,129 $ 1,411,764 $ 1,368,453

Interest bearing deposits 4,762,908 5,500,303 5,432,030 5,549,823 5,263,511

Total deposits 6,169,395 6,874,493 6,865,159 6,961,587 6,631,964

Other borrowings and Federal Home Loan Bank borrowings 1,415,635 671,466 419,793 200,706 611,367

Subordinated notes, net of unamortized debt

issuance costs 147,587 147,541 239,678 239,601 92,115

Trust preferred subordinated debentures, net of unamortized debt issuance costs 60,282 60,280 60,279 60,278 60,277

Other liabilities 88,351 193,540 82,066 86,138 137,043

Total liabilities 7,881,250 7,947,320 7,666,975 7,548,310 7,532,766

Shareholders' equity 882,464 854,862 847,615 834,850 807,200

Total liabilities and shareholders' equity $ 8,763,714 $ 8,802,182 $ 8,514,590 $ 8,383,160 $ 8,339,966

Page-6

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars and shares in thousands, except per share data)

Three Months Ended

2026 2025

Jun 30, Mar 31, Dec 31, Sep 30, Jun 30,

Income Statement:

Total interest and dividend income $ 103,920 $ 102,256 $ 102,328 $ 101,896 $ 98,562

Total interest expense 46,586 44,567 45,080 46,178 44,296

Net interest income 57,334 57,689 57,248 55,718 54,266

Provision for (reversal of) credit losses 83 1,410 581 1,092 622

Net interest income after provision for (reversal of) credit losses 57,251 56,279 56,667 54,626 53,644

Noninterest income

Deposit services

6,389 5,931 6,415 6,069 6,125

Net gain (loss) on sale of securities available for sale — — (7,321) (24,395) —

Gain (loss) on sale of loans 56 118 122 164 99

Trust fees

2,404 2,202 2,148 2,081 1,879

Bank owned life insurance

1,475 986 1,134 871 833

Brokerage services

1,403 1,363 1,348 1,172 1,219

Other

2,277 1,996 1,732 2,048 1,990

Total noninterest income (loss) 14,004 12,596 5,578 (11,990) 12,145

Noninterest expense

Salaries and employee benefits

22,973 24,332 22,816 22,803 22,272

Net occupancy

3,707 3,459 3,715 3,761 3,621

Advertising, travel & entertainment

876 1,043 1,147 907 950

ATM expense

325 430 319 444 405

Professional fees

1,662 1,485 1,343 1,451 1,401

Software and data processing

3,151 3,097 2,859 2,770 3,027

Communications

281 287 273 321 342

FDIC insurance

955 937 937 920 955

Amortization of intangibles

121 132 149 172 198

Loss on redemption of subordinated notes — 791 — — —

Other 4,625 4,583 3,919 3,985 6,086

Total noninterest expense

38,676 40,576 37,477 37,534 39,257

Income before income tax expense 32,579 28,299 24,768 5,102 26,532

Income tax expense 5,742 5,040 3,781 189 4,719

Net income $ 26,837 $ 23,259 $ 20,987 $ 4,913 $ 21,813

Common Share Data:

Weighted-average basic shares outstanding 29,769 29,734 29,863 30,067 30,234

Weighted-average diluted shares outstanding 29,877 29,832 29,943 30,135 30,308

Common shares outstanding end of period 29,803 29,752 29,723 30,066 30,082

Earnings per common share

Basic

$ 0.90 $ 0.78 $ 0.70 $ 0.16 $ 0.72

Diluted

0.90 0.78 0.70 0.16 0.72

Book value per common share 29.61 28.73 28.52 27.77 26.83

Tangible book value per common share 22.84 21.94 21.72 21.04 20.10

Cash dividends paid per common share 0.36 0.36 0.36 0.36 0.36

Selected Performance Ratios:

Return on average assets 1.23 % 1.10 % 0.99 % 0.23 % 1.07 %

Return on average shareholders’ equity 12.33 10.96 9.85 2.40 10.73

Return on average tangible common equity (1)

16.09 14.39 13.03 3.28 14.38

Average yield on earning assets (FTE) (1)

5.17 5.26 5.24 5.27 5.25

Average rate on interest bearing liabilities 2.91 2.88 2.93 3.01 2.98

Net interest margin (FTE) (1)

2.90 3.01 2.98 2.94 2.95

Net interest spread (FTE) (1)

2.26 2.38 2.31 2.26 2.27

Average earning assets to average interest bearing liabilities 128.08 127.84 129.69 129.13 129.33

Noninterest expense to average total assets 1.77 1.92 1.76 1.78 1.92

Efficiency ratio (FTE) (1)

52.96 54.98 52.28 52.99 53.70

(1)Refer to “Non-GAAP Reconciliation” at the end of the financial statement tables in this Earnings Release for a reconciliation of this non-GAAP financial measure to the nearest GAAP financial measure.

Page-7

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars in thousands)

Three Months Ended

2026 2025

Jun 30, Mar 31, Dec 31, Sep 30, Jun 30,

Nonperforming Assets: $ 9,798 $ 9,728 $ 38,243 $ 35,608 $ 32,909

Nonaccrual loans 9,630 9,559 10,486 7,955 4,998

Accruing loans past due more than 90 days — — — — —

Restructured loans 47 34 27,509 27,501 27,512

Other real estate owned 116 128 248 128 380

Repossessed assets 5 7 — 24 19

Asset Quality Ratios:

Ratio of nonaccruing loans to:

Total loans 0.19 % 0.19 % 0.22 % 0.17 % 0.11 %

Ratio of nonperforming assets to:

Total assets 0.11 0.11 0.45 0.42 0.39

Total loans 0.20 0.20 0.79 0.75 0.72

Total loans and OREO 0.20 0.20 0.79 0.75 0.72

Ratio of allowance for loan losses to:

Nonaccruing loans 473.47 480.83 430.10 569.38 888.78

Nonperforming assets 465.35 472.48 117.93 127.20 134.98

Total loans 0.92 0.93 0.94 0.95 0.97

Net charge-offs (recoveries) to average loans outstanding 0.03 0.01 0.07 0.07 0.08

Capital Ratios:

Shareholders’ equity to total assets 10.07 9.71 9.95 9.96 9.68

Common equity tier 1 capital 12.90 12.68 12.87 12.97 13.36

Tier 1 risk-based capital 13.87 13.66 13.88 13.99 14.41

Total risk-based capital 17.14 16.95 18.54 19.01 16.91

Tier 1 leverage capital 9.74 9.74 9.72 9.78 10.03

Period end tangible equity to period end tangible assets (1)

7.95 7.59 7.77 7.73 7.43

Average shareholders’ equity to average total assets 9.97 10.02 10.00 9.72 9.94

(1)Refer to the “Non-GAAP Reconciliation” at the end of the financial statement tables in this Earnings Release for a reconciliation of this non-GAAP financial measure to the nearest GAAP financial measure.

Page-8

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars in thousands)

Three Months Ended

2026 2025

Loan Portfolio Composition Jun 30, Mar 31, Dec 31, Sep 30, Jun 30,

Real Estate Loans:

Construction

$ 600,080 $ 641,818 $ 548,570 $ 519,528 $ 470,380

1-4 Family Residential

716,099 717,298 724,354 730,061 736,108

Commercial Owner-Occupied 362,390 340,898 319,536 336,278 330,163

Commercial Real Estate 2,408,573 2,412,523 2,393,280 2,352,434 2,275,909

Commercial Loans 467,506 456,896 444,720 429,952 380,612

Municipal Loans 357,568 337,089 346,720 353,324 363,746

Loans to Individuals 37,351 39,639 40,811 43,712 45,015

Total Loans $ 4,949,567 $ 4,946,161 $ 4,817,991 $ 4,765,289 $ 4,601,933

Summary of Changes in Allowances:

Allowance for Securities Held to Maturity

Balance at beginning of period $ 25 $ 25 $ 55 $ 55 $ 64

Provision for (reversal of) securities held to maturity — — (30) — (9)

Balance at end of period $ 25 $ 25 $ 25 $ 55 $ 55

Allowance for Loan Losses

Balance at beginning of period $ 45,963 $ 45,100 $ 45,294 $ 44,421 $ 44,623

Loans charged-off (858) (680) (1,115) (1,335) (1,194)

Recoveries of loans charged-off 514 529 327 491 342

Net loans (charged-off) recovered (344) (151) (788) (844) (852)

Provision for (reversal of) loan losses (24) 1,014 594 1,717 650

Balance at end of period $ 45,595 $ 45,963 $ 45,100 $ 45,294 $ 44,421

Allowance for Off-Balance-Sheet Credit Exposures

Balance at beginning of period $ 3,562 $ 3,166 $ 3,149 $ 3,774 $ 3,793

Provision for (reversal of) off-balance-sheet credit exposures 107 396 17 (625) (19)

Balance at end of period $ 3,669 $ 3,562 $ 3,166 $ 3,149 $ 3,774

Total Allowance for Credit Losses $ 49,289 $ 49,550 $ 48,291 $ 48,498 $ 48,250

Page-9

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars in thousands)

Six Months Ended

June 30,

2026 2025

Income Statement:

Total interest and dividend income $ 206,176 $ 198,850

Total interest expense 91,153 90,732

Net interest income 115,023 108,118

Provision for (reversal of) credit losses 1,493 1,380

Net interest income after provision for (reversal of) credit losses 113,530 106,738

Noninterest income

Deposit services

12,320 11,954

Net gain (loss) on sale of securities available for sale

— (554)

Gain (loss) on sale of loans 174 154

Trust fees

4,606 3,644

Bank owned life insurance

2,461 1,632

Brokerage services

2,766 2,339

Other

4,273 3,199

Total noninterest income (loss) 26,600 22,368

Noninterest expense

Salaries and employee benefits

47,305 44,654

Net occupancy

7,166 7,025

Advertising, travel & entertainment

1,919 1,874

ATM expense

755 783

Professional fees

3,147 2,921

Software and data processing

6,248 5,866

Communications

568 725

FDIC insurance

1,892 1,902

Amortization of intangibles

253 421

Loss on redemption of subordinated notes 791 —

Other 9,208 10,175

Total noninterest expense

79,252 76,346

Income before income tax expense 60,878 52,760

Income tax expense 10,782 9,440

Net income $ 50,096 $ 43,320

Common Share Data:

Weighted-average basic shares outstanding 29,752 30,311

Weighted-average diluted shares outstanding 29,857 30,397

Common shares outstanding end of period 29,803 30,082

Earnings per common share

Basic

$ 1.68 $ 1.43

Diluted

1.68 1.42

Book value per common share 29.61 26.83

Tangible book value per common share 22.84 20.10

Cash dividends paid per common share 0.72 0.72

Selected Performance Ratios:

Return on average assets 1.16 % 1.05 %

Return on average shareholders’ equity 11.65 10.65

Return on average tangible common equity (1)

15.26 14.26

Average yield on earning assets (FTE) (1)

5.21 5.24

Average rate on interest bearing liabilities 2.90 3.01

Net interest margin (FTE) (1)

2.95 2.91

Net interest spread (FTE) (1)

2.31 2.23

Average earning assets to average interest bearing liabilities 127.96 128.71

Noninterest expense to average total assets 1.84 1.85

Efficiency ratio (FTE) (1)

53.97 54.36

Page-10

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars in thousands)

Six Months Ended

June 30,

2026 2025

Nonperforming Assets: $ 9,798 $ 32,909

Nonaccrual loans 9,630 4,998

Accruing loans past due more than 90 days — —

Restructured loans 47 27,512

Other real estate owned 116 380

Repossessed assets 5 19

Asset Quality Ratios:

Ratio of nonaccruing loans to:

Total loans 0.19 % 0.11 %

Ratio of nonperforming assets to:

Total assets 0.11 0.39

Total loans 0.20 0.72

Total loans and OREO 0.20 0.72

Ratio of allowance for loan losses to:

Nonaccruing loans 473.47 888.78

Nonperforming assets 465.35 134.98

Total loans 0.92 0.97

Net charge-offs (recoveries) to average loans outstanding 0.02 0.05

Capital Ratios:

Shareholders’ equity to total assets 10.07 9.68

Common equity tier 1 capital 12.90 13.36

Tier 1 risk-based capital 13.87 14.41

Total risk-based capital 17.14 16.91

Tier 1 leverage capital 9.74 10.03

Period end tangible equity to period end tangible assets (1)

7.95 7.43

Average shareholders’ equity to average total assets 9.99 9.84

(1) Refer to the “Non-GAAP Reconciliation” at the end of the financial statement tables in this Earnings Release for a reconciliation of this non-GAAP financial measure to the nearest GAAP financial measure.

Page-11

Southside Bancshares, Inc.

Consolidated Financial Highlights (Unaudited)

(Dollars in thousands)

Six Months Ended

June 30,

Loan Portfolio Composition 2026 2025

Real Estate Loans:

Construction

$ 600,080 $ 470,380

1-4 Family Residential

716,099 736,108

Commercial Owner-Occupied 362,390 330,163

Commercial Real Estate 2,408,573 2,275,909

Commercial Loans 467,506 380,612

Municipal Loans 357,568 363,746

Loans to Individuals 37,351 45,015

Total Loans $ 4,949,567 $ 4,601,933

Summary of Changes in Allowances:

Allowance for Securities Held to Maturity

Balance at beginning of period $ 25 $ —

Provision for (reversal of) securities held to maturity — 55

Balance at end of period $ 25 $ 55

Summary of Changes in Allowances:

Allowance for Loan Losses

Balance at beginning of period $ 45,100 $ 44,884

Loans charged-off (1,538) (1,807)

Recoveries of loans charged-off 1,043 652

Net loans (charged-off) recovered (495) (1,155)

Provision for (reversal of) loan losses 990 692

Balance at end of period $ 45,595 $ 44,421

Allowance for Off-Balance-Sheet Credit Exposures

Balance at beginning of period $ 3,166 $ 3,141

Provision for (reversal of) off-balance-sheet credit exposures 503 633

Balance at end of period $ 3,669 $ 3,774

Total Allowance for Credit Losses $ 49,289 $ 48,250

Page-12

Southside Bancshares, Inc.

Average Balances and Average Yields and Rates (Annualized) (Unaudited)

(Dollars in thousands)

The tables that follow show average earning assets and interest bearing liabilities together with the average yield on the earning assets and the average rate of the interest bearing liabilities for the periods presented. The interest and related yields presented are on a fully taxable-equivalent basis and are therefore non-GAAP measures. See “Non-GAAP Financial Measures” and “Non-GAAP Reconciliation” for more information.

Three Months Ended

June 30, 2026 March 31, 2026

Average Balance Interest

Average Yield/Rate (3)

Average Balance Interest

Average Yield/Rate (3)

ASSETS

Loans (1)

$ 4,957,830 $ 72,431 5.86 % $ 4,879,867 $ 71,515 5.94 %

Loans held for sale 537 7 5.23 % 792 11 5.63 %

Securities:

Taxable investment securities (2)

576,120 4,686 3.26 % 578,480 4,649 3.26 %

Tax-exempt investment securities (2)

863,606 7,550 3.51 % 865,279 7,484 3.51 %

Mortgage-backed and related securities (2)

1,480,922 18,462 5.00 % 1,418,491 17,908 5.12 %

Total securities

2,920,648 30,698 4.22 % 2,862,250 30,041 4.26 %

Federal Home Loan Bank stock, at cost, and equity investments 47,353 215 1.82 % 21,693 249 4.66 %

Interest earning deposits 265,411 2,355 3.56 % 258,860 2,235 3.50 %

Federal funds sold 18,830 171 3.64 % 7,984 71 3.61 %

Total earning assets 8,210,609 105,877 5.17 % 8,031,446 104,122 5.26 %

Cash and due from banks 78,543 82,443

Accrued interest and other assets 512,723 521,219

Less: Allowance for loan losses

(46,315) (45,491)

Total assets $ 8,755,560 $ 8,589,617

LIABILITIES AND SHAREHOLDERS’ EQUITY

Savings accounts $ 722,198 2,722 1.51 % $ 683,270 2,370 1.41 %

Certificates of deposit 1,313,089 12,093 3.69 % 1,328,312 12,402 3.79 %

Interest bearing demand accounts 2,841,740 15,465 2.18 % 3,588,863 21,791 2.46 %

Total interest bearing deposits 4,877,027 30,280 2.49 % 5,600,445 36,563 2.65 %

Federal Home Loan Bank borrowings 828,187 8,248 3.99 % 144,008 975 2.75 %

Subordinated notes, net of unamortized debt issuance costs 147,564 2,686 7.30 % 195,664 3,577 7.41 %

Trust preferred subordinated debentures, net of unamortized debt issuance costs 60,281 922 6.13 % 60,280 915 6.16 %

Repurchase agreements 76,829 629 3.28 % 92,622 784 3.43 %

Other borrowings 420,660 3,821 3.64 % 189,444 1,753 3.75 %

Total interest bearing liabilities 6,410,548 46,586 2.91 % 6,282,463 44,567 2.88 %

Noninterest bearing deposits 1,386,072 1,363,826

Accrued expenses and other liabilities 85,765 82,948

Total liabilities 7,882,385 7,729,237

Shareholders’ equity 873,175 860,380

Total liabilities and shareholders’ equity $ 8,755,560 $ 8,589,617

Net interest income (FTE) $ 59,291 $ 59,555

Net interest margin (FTE) 2.90 % 3.01 %

Net interest spread (FTE) 2.26 % 2.38 %

(1)Interest on loans includes net fees on loans that are not material in amount.

(2)For the purpose of calculating the average yield, the average balance of securities do not include unrealized gains and losses on AFS securities.

(3)Yield/rate includes the impact of applicable derivatives.

Note: As of June 30, 2026 and March 31, 2026, loans totaling $9.6 million were on nonaccrual status. Our policy is to reverse previously accrued but unpaid interest on nonaccrual loans; thereafter, interest income is recorded to the extent received when appropriate.

Page-13

Southside Bancshares, Inc.

Average Balances and Average Yields and Rates (Annualized) (Unaudited)

(Dollars in thousands)

Three Months Ended

December 31, 2025 September 30, 2025

Average Balance Interest

Average Yield/Rate (3)

Average Balance Interest

Average Yield/Rate (3)

ASSETS

Loans (1)

$ 4,788,584 $ 71,616 5.93 % $ 4,640,220 $ 70,240 6.01 %

Loans held for sale 675 12 7.05 % 776 12 6.14 %

Securities:

Taxable investment securities (2)

593,393 4,835 3.23 % 669,712 5,578 3.30 %

Tax-exempt investment securities (2)

893,382 7,939 3.53 % 1,094,978 10,097 3.66 %

Mortgage-backed and related securities (2)

1,284,064 16,493 5.10 % 1,058,860 14,174 5.31 %

Total securities

2,770,839 29,267 4.19 % 2,823,550 29,849 4.19 %

Federal Home Loan Bank stock, at cost, and equity investments 23,287 441 7.51 % 37,937 374 3.91 %

Interest earning deposits 313,810 3,019 3.82 % 334,523 3,631 4.31 %

Federal funds sold 6,906 69 3.96 % 17,546 195 4.41 %

Total earning assets 7,904,101 104,424 5.24 % 7,854,552 104,301 5.27 %

Cash and due from banks 82,585 87,815

Accrued interest and other assets 508,578 455,884

Less: Allowance for loan losses

(45,559) (44,476)

Total assets $ 8,449,705 $ 8,353,775

LIABILITIES AND SHAREHOLDERS’ EQUITY

Savings accounts $ 647,035 2,061 1.26 % $ 618,059 1,772 1.14 %

Certificates of deposit 1,372,879 13,857 4.00 % 1,505,292 15,752 4.15 %

Interest bearing demand accounts 3,474,451 21,827 2.49 % 3,320,993 21,234 2.54 %

Total interest bearing deposits 5,494,365 37,745 2.73 % 5,444,344 38,758 2.82 %

Federal Home Loan Bank borrowings 187,725 1,274 2.69 % 298,138 2,847 3.79 %

Subordinated notes, net of unamortized debt issuance costs 239,648 4,022 6.66 % 169,196 2,319 5.44 %

Trust preferred subordinated debentures, net of unamortized debt issuance costs 60,278 980 6.45 % 60,277 1,025 6.75 %

Repurchase agreements 97,637 866 3.52 % 75,207 662 3.49 %

Other borrowings 14,826 193 5.16 % 35,544 567 6.33 %

Total interest bearing liabilities 6,094,479 45,080 2.93 % 6,082,706 46,178 3.01 %

Noninterest bearing deposits 1,423,350 1,375,075

Accrued expenses and other liabilities 86,863 83,601

Total liabilities 7,604,692 7,541,382

Shareholders’ equity 845,013 812,393

Total liabilities and shareholders’ equity $ 8,449,705 $ 8,353,775

Net interest income (FTE) $ 59,344 $ 58,123

Net interest margin (FTE) 2.98 % 2.94 %

Net interest spread (FTE) 2.31 % 2.26 %

(1)Interest on loans includes net fees on loans that are not material in amount.

(2)For the purpose of calculating the average yield, the average balance of securities do not include unrealized gains and losses on AFS securities.

(3)Yield/rate includes the impact of applicable derivatives.

Note: As of December 31, 2025 and September 30, 2025, loans totaling $10.5 million and $8.0 million, respectively, were on nonaccrual status. Our policy is to reverse previously accrued but unpaid interest on nonaccrual loans; thereafter, interest income is recorded to the extent received when appropriate.

Page-14

Southside Bancshares, Inc.

Average Balances and Average Yields and Rates (Annualized) (Unaudited)

(Dollars in thousands)

Three Months Ended

June 30, 2025

Average Balance Interest

Average Yield/Rate (3)

ASSETS

Loans (1)

$ 4,519,668 $ 67,798 6.02 %

Loans held for sale 1,108 16 5.79 %

Securities:

Taxable investment securities (2)

735,669 6,205 3.38 %

Tax-exempt investment securities (2)

1,130,903 10,351 3.67 %

Mortgage-backed and related securities (2)

1,003,887 13,040 5.21 %

Total securities

2,870,459 29,596 4.14 %

Federal Home Loan Bank stock, at cost, and equity investments 31,169 524 6.74 %

Interest earning deposits 259,617 2,753 4.25 %

Federal funds sold 27,778 308 4.45 %

Total earning assets 7,709,799 100,995 5.25 %

Cash and due from banks 84,419

Accrued interest and other assets 452,573

Less: Allowance for loan losses

(44,747)

Total assets $ 8,202,044

LIABILITIES AND SHAREHOLDERS’ EQUITY

Savings accounts $ 596,125 1,451 0.98 %

Certificates of deposit 1,407,017 14,905 4.25 %

Interest bearing demand accounts 3,311,330 21,071 2.55 %

Total interest bearing deposits 5,314,472 37,427 2.82 %

Federal Home Loan Bank borrowings 394,119 3,721 3.79 %

Subordinated notes, net of unamortized debt issuance costs 92,097 935 4.07 %

Trust preferred subordinated debentures, net of unamortized debt issuance costs 60,276 1,015 6.75 %

Repurchase agreements 72,295 634 3.52 %

Other borrowings 28,022 564 8.07 %

Total interest bearing liabilities 5,961,281 44,296 2.98 %

Noninterest bearing deposits 1,339,463

Accrued expenses and other liabilities 85,827

Total liabilities 7,386,571

Shareholders’ equity 815,473

Total liabilities and shareholders’ equity $ 8,202,044

Net interest income (FTE) $ 56,699

Net interest margin (FTE) 2.95 %

Net interest spread (FTE) 2.27 %

(1)Interest on loans includes net fees on loans that are not material in amount.

(2)For the purpose of calculating the average yield, the average balance of securities do not include unrealized gains and losses on AFS securities.

(3)Yield/rate includes the impact of applicable derivatives.

Note: As of June 30, 2025, loans totaling $5.0 million were on nonaccrual status. Our policy is to reverse previously accrued but unpaid interest on nonaccrual loans; thereafter, interest income is recorded to the extent received when appropriate.

Page-15

Southside Bancshares, Inc.

Average Balances and Average Yields and Rates (Annualized) (Unaudited)

(Dollars in thousands)

Six Months Ended

June 30, 2026 June 30, 2025

Average Balance Interest Average Yield/Rate Average Balance Interest Average Yield/Rate

ASSETS

Loans (1)

$ 4,919,064 $ 143,946 5.90 % $ 4,572,492 $ 135,958 6.00 %

Loans held for sale 664 18 5.47 % 931 27 5.85 %

Securities:

Taxable investment securities (2)

577,293 9,335 3.26 % 742,375 12,568 3.41 %

Tax-exempt investment securities (2)

864,438 15,034 3.51 % 1,132,736 20,604 3.67 %

Mortgage-backed and related securities (2)

1,449,879 36,370 5.06 % 1,022,360 26,563 5.24 %

Total securities 2,891,610 60,739 4.24 % 2,897,471 59,735 4.16 %

Federal Home Loan Bank stock, at cost, and equity investments 34,594 464 2.70 % 37,194 1,007 5.46 %

Interest earning deposits 262,154 4,590 3.53 % 289,586 6,123 4.26 %

Federal funds sold 13,437 242 3.63 % 35,751 786 4.43 %

Total earning assets 8,121,523 209,999 5.21 % 7,833,425 203,636 5.24 %

Cash and due from banks 80,482 87,046

Accrued interest and other assets 516,908 455,245

Less: Allowance for loan losses (45,905) (44,925)

Total assets $ 8,673,008 $ 8,330,791

LIABILITIES AND SHAREHOLDERS’ EQUITY

Savings accounts $ 702,841 5,092 1.46 % $ 595,045 2,880 0.98 %

Certificates of deposit 1,320,658 24,495 3.74 % 1,372,110 29,311 4.31 %

Interest bearing demand accounts 3,213,238 37,256 2.34 % 3,358,573 42,483 2.55 %

Total interest bearing deposits 5,236,737 66,843 2.57 % 5,325,728 74,674 2.83 %

Federal Home Loan Bank borrowings 487,988 9,223 3.81 % 503,898 9,558 3.83 %

Subordinated notes, net of unamortized debt issuance costs 171,481 6,263 7.37 % 92,079 1,867 4.09 %

Trust preferred subordinated debentures, net of unamortized debt issuance costs 60,280 1,837 6.15 % 60,275 2,029 6.79 %

Repurchase agreements 84,682 1,413 3.36 % 73,785 1,300 3.55 %

Other borrowings 305,691 5,574 3.68 % 30,528 1,304 8.61 %

Total interest bearing liabilities 6,346,859 91,153 2.90 % 6,086,293 90,732 3.01 %

Noninterest bearing deposits 1,375,011 1,337,210

Accrued expenses and other liabilities 84,325 87,131

Total liabilities 7,806,195 7,510,634

Shareholders’ equity 866,813 820,157

Total liabilities and shareholders’ equity $ 8,673,008 $ 8,330,791

Net interest income (FTE) $ 118,846 $ 112,904

Net interest margin (FTE) 2.95 % 2.91 %

Net interest spread (FTE) 2.31 % 2.23 %

(1)Interest on loans includes net fees on loans that are not material in amount.

(2)For the purpose of calculating the average yield, the average balance of securities do not include unrealized gains and losses on AFS securities.

Note: As of June 30, 2026 and 2025, loans totaling $9.6 million and $5.0 million, respectively, were on nonaccrual status. Our policy is to reverse previously accrued but unpaid interest on nonaccrual loans; thereafter, interest income is recorded to the extent received when appropriate.

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Southside Bancshares, Inc.

Non-GAAP Reconciliation (Unaudited)

(Dollars and shares in thousands, except per share data)

The following tables set forth the reconciliation of return on average shareholders’ equity to return on average tangible common equity, book value per share to tangible book value per share, net interest income to net interest income adjusted to a fully taxable-equivalent basis assuming a 21% marginal tax rate for interest earned on tax-exempt assets such as municipal loans and investment securities, along with the calculation of total revenue, adjusted noninterest expense, efficiency ratio (FTE), net interest margin (FTE) and net interest spread (FTE) for the applicable periods presented.

Three Months Ended Six Months Ended

2026 2025 2026 2025

Jun 30, Mar 31, Dec 31, Sep 30, Jun 30, Jun 30, Jun 30,

Reconciliation of return on average common equity to return on average tangible common equity:

Net income $ 26,837 $ 23,259 $ 20,987 $ 4,913 $ 21,813 $ 50,096 $ 43,320

After-tax amortization expense 96 104 117 136 157 200 333

Adjusted net income available to common shareholders $ 26,933 $ 23,363 $ 21,104 $ 5,049 $ 21,970 $ 50,296 $ 43,653

Average shareholders' equity $ 873,175 $ 860,380 $ 845,013 $ 812,393 $ 815,473 $ 866,813 $ 820,157

Less: Average intangibles for the period (201,949) (202,078) (202,217) (202,380) (202,569) (202,013) (202,676)

Average tangible shareholders' equity $ 671,226 $ 658,302 $ 642,796 $ 610,013 $ 612,904 $ 664,800 $ 617,481

Return on average shareholders’ equity 12.33 % 10.96 % 9.85 % 2.40 % 10.73 % 11.65 % 10.65 %

Return on average tangible common equity 16.09 % 14.39 % 13.03 % 3.28 % 14.38 % 15.26 % 14.26 %

Reconciliation of book value per share to tangible book value per share:

Common equity at end of period $ 882,464 $ 854,862 $ 847,615 $ 834,850 $ 807,200 $ 882,464 $ 807,200

Less: Intangible assets at end of period (201,875) (201,996) (202,128) (202,277) (202,449) (201,875) (202,449)

Tangible common shareholders' equity at end of period $ 680,589 $ 652,866 $ 645,487 $ 632,573 $ 604,751 $ 680,589 $ 604,751

Total assets at end of period $ 8,763,714 $ 8,802,182 $ 8,514,590 $ 8,383,160 $ 8,339,966 $ 8,763,714 $ 8,339,966

Less: Intangible assets at end of period (201,875) (201,996) (202,128) (202,277) (202,449) (201,875) (202,449)

Tangible assets at end of period $ 8,561,839 $ 8,600,186 $ 8,312,462 $ 8,180,883 $ 8,137,517 $ 8,561,839 $ 8,137,517

Period end tangible equity to period end tangible assets 7.95 % 7.59 % 7.77 % 7.73 % 7.43 % 7.95 % 7.43 %

Common shares outstanding end of period 29,803 29,752 29,723 30,066 30,082 29,803 30,082

Tangible book value per common share $ 22.84 $ 21.94 $ 21.72 $ 21.04 $ 20.10 $ 22.84 $ 20.10

Reconciliation of efficiency ratio to efficiency ratio (FTE), net interest margin to net interest margin (FTE) and net interest spread to net interest spread (FTE):

Net interest income (GAAP) $ 57,334 $ 57,689 $ 57,248 $ 55,718 $ 54,266 $ 115,023 $ 108,118

Tax-equivalent adjustments:

Loans 550 538 545 553 565 1,088 1,146

Tax-exempt investment securities 1,407 1,328 1,551 1,852 1,868 2,735 3,640

Net interest income (FTE) (1)

59,291 59,555 59,344 58,123 56,699 118,846 112,904

Noninterest income 14,004 12,596 5,578 (11,990) 12,145 26,600 22,368

Nonrecurring income (2)

(543) (47) 7,066 24,395 — (590) 554

Total revenue $ 72,752 $ 72,104 $ 71,988 $ 70,528 $ 68,844 $ 144,856 $ 135,826

Noninterest expense $ 38,676 $ 40,576 $ 37,477 $ 37,534 $ 39,257 $ 79,252 $ 76,346

Pre-tax amortization expense (121) (132) (149) (172) (198) (253) (421)

Nonrecurring expense (3)

(26) (799) 306 14 (2,090) (825) (2,091)

Adjusted noninterest expense $ 38,529 $ 39,645 $ 37,634 $ 37,376 $ 36,969 $ 78,174 $ 73,834

Efficiency ratio 54.42 % 56.44 % 53.85 % 54.87 % 55.67 % 55.43 % 56.34 %

Efficiency ratio (FTE) (1)

52.96 % 54.98 % 52.28 % 52.99 % 53.70 % 53.97 % 54.36 %

Average earning assets $ 8,210,609 $ 8,031,446 $ 7,904,101 $ 7,854,552 $ 7,709,799 $ 8,121,523 $ 7,833,425

Net interest margin 2.80 % 2.91 % 2.87 % 2.81 % 2.82 % 2.86 % 2.78 %

Net interest margin (FTE) (1)

2.90 % 3.01 % 2.98 % 2.94 % 2.95 % 2.95 % 2.91 %

Net interest spread 2.17 % 2.28 % 2.21 % 2.14 % 2.15 % 2.22 % 2.11 %

Net interest spread (FTE) (1)

2.26 % 2.38 % 2.31 % 2.26 % 2.27 % 2.31 % 2.23 %

(1)These amounts are presented on a fully taxable-equivalent basis and are non-GAAP measures.

(2)These adjustments may include net gain or loss on sale of securities available for sale, BOLI income related to death benefits realized and other investment income or loss in the periods where applicable.

(3)These adjustments may include loss on redemption of subordinated notes, foreclosure expenses, branch closure expenses and other miscellaneous expense, in the periods where applicable.

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