Fourth Quarter Highlights

2 "Safe Harbor" Statement Under the Private Securities Litigation Reform Act of 1995 "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 loan 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 loan losses, future capital structure or changes therein, as well as the plans and objectives of management for Prosperity's future operations, future or proposed acquisitions, including the proposed transactions with First Bancshares and Lone Star, 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 each of the proposed transactions, and statements about the assumptions underlying any such statement, as well as expectations regarding the effects of the COVID-19 pandemic on Prosperity's operating income, financial condition and cash flows. 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. Many possible events or factors could adversely affect the future financial results and performance of Prosperity, First Bancshares, Lone Star or the combined company and could cause those results or performance to differ materially from those expressed in or implied by the forward-looking statements. Such risks and uncertainties include, among others: the occurrence of any event, change or other circumstance that could give rise to the right of a party to terminate the merger agreement with First Bancshares or Lone Star, as applicable, the outcome of any legal proceedings that may be instituted against Prosperity, First Bancshares or Lone Star, delays in completing either of the transactions, the failure to obtain necessary regulatory approvals (and the risk that such approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of each of the transactions) or First Bancshares shareholder approval or Lone Star shareholder approval or to satisfy any of the other conditions to the transactions on a timely basis or at all, the possibility that the anticipated benefits of the transactions are not realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of the two companies or as a result of the strength of the economy and competitive factors generally, or specifically in the West Texas area and the West, North and Central Texas area where First Bancshares and Lone Star, respectively, do a majority of their respective business and Prosperity has a significant presence, the possibility that the transactions may be more expensive to complete than anticipated, including as a result of unexpected factors or events, diversion of management's attention from ongoing business operations and opportunities, potential adverse reactions or changes to business or employee relationships, including those resulting from the announcement or completion of the transactions, Prosperity's ability to complete the acquisition and integration of First Bancshares and of Lone Star successfully, and the dilution caused by Prosperity's issuance of additional shares of its common stock in connection with the transactions. 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, 2021, 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. PB LISTED NYSE

View entire presentation