PROSPERITY BANCSHARES AND STELLAR BANCORP ANNOUNCE RECEIPT OF REGULATORY APPROVALS FOR PROSPERITY’S PENDING ACQUISITION OF STELLAR (Form 8-K)

PROSPERITY BANCSHARES AND STELLAR BANCORP ANNOUNCE RECEIPT OF REGULATORY APPROVALS FOR PROSPERITY'S PENDING ACQUISITION OF STELLAR

FOR IMMEDIATE RELEASE

HOUSTON, TEXAS, April 22, 2026. Prosperity Bancshares, Inc.® (NYSE: PB) ("Prosperity"), the parent company of Prosperity Bank®, and Stellar Bancorp, Inc. (NYSE: STEL) ("Stellar"), the parent company of Stellar Bank, today announced the receipt of all regulatory approvals necessary to complete Prosperity's previously announced proposed acquisition of Stellar.

A waiver of prior approval with respect to the merger of the holding companies has been granted by the Federal Reserve Bank of Dallas, and each of the Federal Deposit Insurance Corporation and the Texas Department of Banking have approved the merger of Stellar Bank with and into Prosperity Bank following the merger of the holding companies.

The special meeting of Stellar shareholders to consider and vote on the Agreement and Plan of Merger, dated January 27, 2026, by and between Prosperity and Stellar (the "Merger Agreement"), is scheduled to be held on May 27, 2026. The merger is expected to be completed on or about July 1, 2026, subject to approval by Stellar shareholders and the satisfaction or waiver of other customary closing conditions set forth in the Merger Agreement.

About Prosperity Bancshares, Inc.®

As of December 31, 2025, Prosperity Bancshares, Inc.® is a $38.463 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 312 full-service banking locations: 62 in the Houston area, including The Woodlands; 36 in the South Texas area including Corpus Christi and Victoria; 61 in the Dallas/Fort Worth area; 22 in the East Texas area; 28 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; 8 in the Tulsa, Oklahoma area, 18 in the Central, South Texas and San Antonio areas doing business as American Bank and 11 in the San Antonio area doing business as Texas Partners Bank.

About Stellar Bancorp, Inc.

Stellar Bancorp, Inc. is a bank holding company headquartered in Houston, Texas. Stellar's principal banking subsidiary, Stellar Bank, provides a diversified range of commercial banking services primarily to small- to medium-sized businesses and individual customers across Houston, Dallas, Beaumont and surrounding communities in Texas.

Cautionary Notes on Forward Looking Statements