PROSPERITY BANCSHARES, INC. COMPLETES MERGER WITH LONE STAR STATE BANCSHARES, INC.

Prosperity Bancshares, Inc. ('Prosperity') (NYSE: PB), the parent company of Prosperity Bank, today announced the completion of the merger of Lone Star State Bancshares, Inc. ('LS Bancshares') with and into Prosperity and the merger of LS Bancshares' wholly owned subsidiary, Lone Star State Bank of West Texas ('Lone Star'), headquartered in Lubbock, Texas, with and into Prosperity Bank, all effective on April 1, 2024.

Under 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 and dilutive securities of LS Bancshares.

Alan Lackey, Lone Star Chief Executive Officer, will serve as West Texas Area President and Melisa Roberts, Lone Star Chief Lending Officer, will serve as West Texas Area Vice President, joining Mike Marshall, Prosperity Bank's West Texas Area Chairman. Additional members of Lone Star management will maintain leadership roles in the combined organization.

Lone Star operated five (5) banking centers in the West Texas area, including its main office in Lubbock, and one (1) banking center in each of Brownfield, Midland, Odessa and Big Spring, Texas. Lone Star banking locations will continue to operate under the Lone Star name until the operational integration, which is scheduled for October 28, 2024. At that time, Lone Star customers may begin using any of Prosperity Bank's combined 288 full service banking centers.

About Prosperity Bancshares, Inc. As of December 31, 2023, Prosperity Bancshares, Inc. is a $38.548 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

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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 288 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; 49 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.

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