FOR IMMEDIATE RELEASE

PROSPERITY BANCSHARES, INC.®

REPORTS FIRST QUARTER

2025 EARNINGS

HOUSTON, April 23, 2025. Prosperity Bancshares, Inc.® (NYSE: PB), the parent company of Prosperity Bank® (collectively, “Prosperity”), reported net income of $130.2 million for the quarter ended March 31, 2025 compared with $110.4 million for the same period in 2024. Net income per diluted common share was $1.37 for the quarter ended March 31, 2025 compared with $1.18 for the same period in 2024. The annualized return on first quarter average assets was 1.34%. Additionally, borrowings decreased $500.0 million during the first quarter of 2025. Nonperforming assets remain low at 0.24% of first quarter average interest-earning assets.

“I am pleased to announce a 17.9% increase in net income and a 16.1% increase in earnings per share, each compared with the first quarter of 2024. As we predicted, our net interest margin continues to increase as our assets reprice higher. We expect this trend to continue over the next several years,” said David Zalman, Prosperity’s Senior Chairman and Chief Executive Officer.

“We and others believe that Prosperity is doing the right thing. Prosperity has been ranked as one of Forbes Best Banks since the list’s inception in 2010 and was ranked in the top 10 for 14 consecutive years. Additionally, Prosperity was named the “Best Overall Bank in Texas” by Money for 2024-2025 and was ranked among “America’s Best Regional Banks” by Newsweek in 2025,” added Zalman.

“Prosperity continues to focus on long term relationships and our customers’ success while maintaining strong asset quality, solid earnings and a fair return to shareholders. Prosperity maintained a high tangible equity to tangible assets ratio of 11.2%, with tangible equity of $3.952 billion,” continued Zalman.

“The Texas economy continues to expand. Employment growth was solid, and sales tax revenue increased broadly according to the Federal Reserve Bank of Dallas Texas Economic Indicators dated April 3, 2025. The March 2025 Texas Business Outlook Surveys showed continued expansion in wages and benefits across all sectors,” stated Zalman.

“Despite the uncertainty with tariffs, our teams in Texas and Oklahoma are optimistic based on conversations with our customers about their outlook and plans. We will continue to be opportunistic, work hard, stay close to our customers and their needs and maintain a quality loan portfolio,” continued Zalman.

“I would like to thank our customers for their business and continued trust and our associates, directors and officers for their hard work and dedication,” concluded Zalman.

Results of Operations for the Three Months Ended March 31, 2025

Net income was $130.2 million(2) for the three months ended March 31, 2025 compared with $110.4 million(3) for the same period in 2024, an increase of $19.8 million or 17.9%. Net income per diluted common share was $1.37 for the three months ended March 31, 2025 compared with $1.18 for the same period in 2024, an increase of 16.1%. The changes were primarily due to an increase in net interest income, partially offset by an increase in salaries and benefits and provision for income taxes. On a linked quarter basis, net income was $130.2 million(2) for the three months ended March 31, 2025 compared with $130.1 million(4) for the three months ended December 31, 2024. Net income per diluted common share was $1.37 for the three months ended March 31, 2025 and December 31, 2024. Annualized returns on average assets, average common equity and average tangible common equity for the three months ended March 31, 2025 were 1.34%, 6.94% and 13.23%(1), respectively. Prosperity’s efficiency ratio (excluding net gains and losses on the sale, write-down or write-up of assets and securities) was 45.71%(1) for the three months ended March 31, 2025.

Net interest income before provision for credit losses was $265.4 million for the three months ended March 31, 2025 compared with $238.2 million for the same period in 2024, an increase of $27.1 million or 11.4%. The change was primarily due to an increase in the average balances and average rates on loans, an increase in the average balances on federal funds sold and other earning assets and a decrease in the average balances and rates on other borrowings, partially offset by a decrease in the average balances on investment securities and an increase in the average balances on interest-bearing deposits. Net interest income before provision for credit losses decreased $2.4 million or 0.9% to $265.4 million for the three months ended March 31, 2025 compared with $267.8 million for the three months ended December 31, 2024.

The net interest margin on a tax equivalent basis was 3.14% for the three months ended March 31, 2025 compared with 2.79% for the same period in 2024. The change was primarily due to an increase in the average balances and average rates on loans, an increase in the average balances on federal funds sold and other earning assets and a decrease in the average balances and average rates on other borrowings, partially offset by a decrease in the average balances on investment securities and an increase in the average balances on interest-bearing deposits. The net interest margin on a tax equivalent basis was 3.14% for the three months ended March 31, 2025 compared with 3.05% for the three months ended December 31, 2024. The change was primarily due to a decrease in the average balances and average rates on other borrowings and a decrease in the average rates on interest-bearing deposits, partially offset by a decrease in the average balances and average rates on loans and a decrease in the average balances and average rates on federal funds sold and other earning assets.

Noninterest income was $41.3 million for the three months ended March 31, 2025 compared with $38.9 million for the same period in 2024, an increase of $2.4 million or 6.3%. The change was primarily due to increases in service charges on deposit accounts, nonsufficient funds fees and other noninterest income, partially offset by a decrease in trust income. Noninterest income was $41.3 million for the three months ended March 31, 2025 compared with $39.8 million for the three months ended December 31, 2024, an increase of $1.5 million or 3.7%.

Noninterest expense was $140.3 million for the three months ended March 31, 2025 compared with $135.8 million for the same period in 2024, an increase of $4.5 million or 3.3%, primarily due to an increase in salaries and benefits related to the merger of Lone Star State Bancshares, Inc. (“Lone Star”) with Prosperity Bancshares and the merger of Lone Star State Bank of West Texas (“Lone

Star Bank”) with Prosperity Bank, both effective on April 1, 2024 (collectively, the “Merger”). Noninterest expense was $140.3 million for the three months ended March 31, 2025 compared with $141.5 million for the three months ended December 31, 2024, a decrease of $1.2 million or 0.9%.

Balance Sheet Information

At March 31, 2025, Prosperity had $38.765 billion in total assets, an increase of $8.2 million, compared with $38.757 billion at March 31, 2024. Linked quarter total assets decreased $802.1 million compared with $39.567 billion at December 31, 2024.

Loans were $21.978 billion at March 31, 2025, an increase of $712.3 million or 3.3%, compared with $21.265 billion at March 31, 2024, primarily due to the Merger. Linked quarter loans decreased $171.6 million from $22.149 billion at December 31, 2024.

Loans, excluding Warehouse Purchase Program loans, were $20.920 billion at March 31, 2025 compared with $20.400 billion at March 31, 2024, an increase of $519.4 million or 2.5%, and compared with $21.068 billion at December 31, 2024, a decrease of $148.6 million.

Deposits were $28.027 billion at March 31, 2025, an increase of $851.3 million or 3.1%, compared with $27.176 billion at March 31, 2024, primarily due to the Merger. Linked quarter deposits decreased $354.5 million from $28.381 billion at December 31, 2024.

The table below provides detail on the impact of loans acquired and deposits assumed in the Merger:

Excluding loans acquired in the Merger and new production at the acquired banking centers since April 1, 2024, loans at March 31, 2025 decreased $264.3 million compared with March 31, 2024 and decreased $90.6 million compared with December 31, 2024.

Excluding deposits assumed in the Merger and new deposits generated at the acquired banking centers since April 1, 2024, deposits at March 31, 2025 decreased $132.0 million compared with March 31, 2024 and decreased $244.3 million compared with December 31, 2024.

Asset Quality

Nonperforming assets totaled $81.4 million or 0.24% of quarterly average interest-earning assets at March 31, 2025 compared with $83.8 million or 0.24% of quarterly average interest-earning assets at March 31, 2024 and $81.5 million or 0.23% of quarterly average interest-earning assets at December 31, 2024.

The allowance for credit losses on loans and on off-balance sheet credit exposures was $386.7 million at March 31, 2025 compared with $366.7 million at March 31, 2024 and $389.5 million at December 31, 2024. There was no provision for credit losses for the three months ended March 31, 2025, March 31, 2024 and December 31, 2024.

The allowance for credit losses on loans was $349.1 million or 1.59% of total loans at March 31, 2025 compared with $330.2 million or 1.55% of total loans at March 31, 2024 and $351.8 million or 1.59% of total loans at December 31, 2024. Excluding Warehouse Purchase Program loans, the allowance for credit losses on loans to total loans was 1.67%(1) at March 31, 2025 compared with 1.62%(1) at March 31, 2024 and 1.67%(1) at December 31, 2024.

Net charge-offs were $2.7 million for the three months ended March 31, 2025 compared with net charge-offs of $2.1 million for the three months ended March 31, 2024 and net charge-offs of $2.6 million for the three months ended December 31, 2024. For the first quarter of 2025, $8.3 million of reserves on resolved purchased credit deteriorated (“PCD”) loans without any related charge-offs were released to the general reserve.

Dividend

Prosperity Bancshares declared a second quarter 2025 cash dividend of $0.58 per share to be paid on July 1, 2025, to all shareholders of record as of June 13, 2025.

Merger of Lone Star State Bancshares, Inc.

On April 1, 2024, Prosperity completed the merger of Lone Star and its wholly owned subsidiary Lone Star Bank, headquartered in Lubbock, Texas. Lone Star Bank operated 5 full-service banking offices in the West Texas area, including its main office in Lubbock, and 1 banking center in each of Brownfield, Midland, Odessa and Big Spring, Texas.

Pursuant to the terms of the definitive agreement, Prosperity issued 2,376,182 shares of Prosperity common stock plus approximately $64.1 million in cash for all outstanding shares of Lone Star in the second quarter of 2024. This resulted in goodwill of $106.7 million as of March 31, 2025.

Conference Call

Prosperity’s management team will host a conference call on Wednesday, April 23, 2025, at 11:30 a.m. Eastern Time (10:30 a.m. Central Time) to discuss Prosperity’s first quarter 2025 earnings. Individuals and investment professionals may participate in the call by dialing 877-883-0383 for domestic participants, or 412-902-6506 for international participants. The participant elite entry number is 7564851.

Alternatively, individuals may listen to the live webcast of the presentation by visiting Prosperity’s website at www.prosperitybankusa.com. The webcast may be accessed from Prosperity’s Investor Relations page by selecting “Presentations, Webcasts & Calls” from the menu and following the instructions.

Non-GAAP Financial Measures

Prosperity’s management uses certain non-GAAP financial measures to evaluate its performance. Specifically, for internal planning and forecasting purposes, Prosperity reviews each of diluted earnings per share, return on average assets, return on average common equity, and return on average tangible common equity, in each case excluding merger related provision for credit losses, net of tax, merger related expenses, net of tax, Federal Deposit Insurance Corporation (“FDIC”) special assessment, net of tax, and net gain on the sale or write-up of securities, net of tax; return on average tangible common equity; tangible book value per share; the tangible equity to tangible assets ratio; allowance for credit losses to total loans excluding Warehouse Purchase Program loans; the efficiency ratio, excluding net gains and losses on the sale, write-down or write-up of assets and securities; and the efficiency ratio, excluding net gains and losses on the sale, write-down or write-up of assets and securities, merger related expenses, and FDIC special assessment. Prosperity believes these non-GAAP financial measures provide information useful to investors in understanding Prosperity’s financial results and their presentation, together with the accompanying reconciliations, provides a more complete understanding of factors and trends affecting Prosperity’s business and allows investors to view performance in a manner similar to management, the entire financial services sector, bank stock analysts and bank regulators. Further, Prosperity believes that these non-GAAP financial measures provide useful information by excluding certain items that may not be indicative of its core operating earnings and business outlook. These non-GAAP financial measures should not be considered a substitute for, nor of greater importance than, GAAP basis financial measures and results; Prosperity strongly encourages investors to review its consolidated financial statements in their entirety and not to rely on any single financial measure. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies’ non-GAAP financial measures having the same or similar names. Please refer to the “Notes to Selected Financial Data” at the end of this Earnings Release for a reconciliation of these non-GAAP financial measures to the nearest respective GAAP financial measures.

Prosperity Bancshares, Inc. ®

As of March 31, 2025, Prosperity Bancshares, Inc.® is a $38.765 billion Houston, Texas based regional financial holding company providing personal banking services and investments to consumers and businesses throughout Texas and Oklahoma. Founded in 1983, Prosperity believes in a community banking philosophy, taking care of customers, businesses and communities in the areas it serves by providing financial solutions to simplify everyday financial needs. In addition to offering traditional deposit and loan products, Prosperity offers digital banking solutions, credit and debit cards, mortgage services, retail brokerage services, trust and wealth management, and treasury management.

Prosperity currently operates 284 full-service banking locations: 65 in the Houston area, including The Woodlands; 30 in the South Texas area including Corpus Christi and Victoria; 62 in the Dallas/Fort Worth area; 22 in the East Texas area; 31 in the Central Texas area including Austin and San Antonio; 45 in the West Texas area including Lubbock, Midland-Odessa, Abilene, Amarillo and Wichita Falls; 15 in the Bryan/College Station area; 6 in the Central Oklahoma area; and 8 in the Tulsa, Oklahoma area.

Cautionary Notes on Forward-Looking Statements

“Safe Harbor” Statement under the Private Securities Litigation Reform Act of 1995: This release contains, and the remarks by Prosperity’s management on the conference call may contain, forward-looking statements within the meaning of the federal securities laws, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. From time to time, oral or written forward-looking statements may also be included in other information released to the public. Such forward-looking statements are typically, but not exclusively, identified by the use in the statements of words or phrases such as “aim,” “anticipate,” “believe,” “estimate,” “expect,” “goal,” “guidance,” “intend,” “is anticipated,” “is expected,” “is intended,” “objective,” “plan,” “projected,” “projection,” “will affect,” “will be,” “will continue,” “will decrease,” “will grow,” “will impact,” “will increase,” “will incur,” “will reduce,” “will remain,” “will result,” “would be,” variations of such words or phrases (including where the word “could,” “may,” or “would” is used rather than the word “will” in a phrase) and similar words and phrases indicating that the statement addresses some future result, occurrence, plan or objective. Forward-looking statements include all statements other than statements of historical fact, including forecasts or trends, and are based on current expectations, assumptions, estimates and projections about Prosperity Bancshares and its subsidiaries. These forward-looking statements may include information about Prosperity’s possible or assumed future economic performance or future results of operations, including future revenues, income, expenses, provision for credit losses, provision for taxes, effective tax rate, earnings per share and cash flows and Prosperity’s future capital expenditures and dividends, future financial condition and changes therein, including changes in Prosperity’s loan portfolio and allowance for credit losses, changes in deposits, borrowings and the investment securities portfolio, future capital structure or changes therein, as well as the plans and objectives of management for Prosperity’s future operations, future or proposed acquisitions, the future or expected effect of acquisitions on Prosperity’s operations, results of operations, financial condition, and future economic performance, statements about the anticipated benefits of any proposed transactions, and statements about the assumptions underlying any such statement. These forward‑looking statements are not guarantees of future performance and are based on expectations and assumptions Prosperity currently believes to be valid. Because forward-looking statements relate to future results and occurrences, many of which are outside of Prosperity’s control, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. These risks and uncertainties include, but are not limited to, whether Prosperity can: successfully identify acquisition targets and integrate the businesses of acquired companies and banks; continue to sustain its current internal growth rate or total growth rate; provide products and services that appeal to its customers; continue to have access to debt and equity capital markets; and achieve its sales objectives. Other risks include, but are not limited to: the possibility that credit quality could deteriorate; actions of competitors; changes in laws and regulations (including changes in governmental interpretations of regulations and changes in accounting standards); the possibility that the anticipated benefits of an acquisition transaction are not realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of two companies or as a result of the strength of the economy and competitive factors generally; a deterioration or downgrade in the credit quality and credit agency ratings of the securities in Prosperity’s securities portfolio; customer and consumer demand, including customer and consumer response to marketing; effectiveness of spending, investments or programs; fluctuations in the cost and availability of supply chain resources; economic conditions, including currency rate, interest rate and commodity price fluctuations; changes in trade policies by the United States or other countries, such as tariffs or retaliatory tariffs; and the effect, impact, potential duration or other implications of weather and climate-related events. Prosperity disclaims any obligation to update such factors or to publicly announce the results of any revisions to any of the forward-looking statements included herein to reflect future events or developments. These and various other factors are discussed in Prosperity’s Annual Report on Form 10-K for the year ended December 31, 2024, and other reports and statements Prosperity has filed with the Securities and Exchange Commission (“SEC”). Copies of the SEC filings for Prosperity may be downloaded from the Internet at no charge from http://www.prosperitybankusa.com.

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Prosperity Bancshares, Inc.®

Financial Highlights (Unaudited)

(In thousands)

(A) Includes $(1,374), $(2,056), $(1,070), $(2,007) and $(2,954) in unrealized losses on available for sale securities for the quarterly periods ended March 31, 2025, December 31, 2024, September 30, 2024, June 30, 2024 and March 31, 2024, respectively.

(B) Includes $(1,085), $(1,624), $(845), $(1,586) and $(2,333) in after-tax unrealized losses on available for sale securities for the quarterly periods ended March 31, 2025, December 31, 2024, September 30, 2024, June 30, 2024 and March 31, 2024, respectively.

Prosperity Bancshares, Inc.®

Financial Highlights (Unaudited)

(In thousands)

(C) Interest income on securities was reduced by net premium amortization of $5,027, $5,609, $5,574, $5,831 and $5,822 for the three months ended March 31, 2025, December 31, 2024, September 30, 2024, June 30, 2024 and March 31, 2024, respectively.

Prosperity Bancshares, Inc. ®

Financial Highlights (Unaudited)

(Dollars and share amounts in thousands, except per share data and market prices)