PROSPERITY BANCSHARES INC

Acquisition of American Bank Holding Corporation— On January 1, 2026, the Company completed the merger of American Bank Holding Corporation (“American”) into the Company and the subsequent merger of its wholly owned subsidiary American Bank, N.A. (“American Bank”), into the Bank (collectively, the “American Merger”). American Bank operated 18 banking offices and 2 loan production offices in South and Central Texas including its main office in Corpus Christi, and banking offices in San Antonio, Austin, Victoria and the greater Corpus Christi area including Port Aransas and Rockport and a loan production office in Houston, Texas. Pursuant to the terms of the definitive agreement, the Company issued 4,439,938 shares of its common stock for all outstanding shares of American common stock in the first quarter of 2026.

Acquisition of Southwest Bancshares, Inc.— On February 1, 2026, the Company completed the merger of Southwest Bancshares, Inc. (“Southwest”) into the Company and the subsequent merger of its wholly owned subsidiary Texas Partners Bank (“Texas Partners”), into the Bank (collectively, the “Southwest Merger”). Texas Partners operated 11 banking offices in Central Texas including its main office in San Antonio, and banking offices in the San Antonio area, Austin and the Hill Country. Pursuant to the terms of the definitive agreement, the Company issued 4,094,974 shares of its common stock for all outstanding shares of Southwest common stock in the first quarter of 2026.

Pending Acquisition of Stellar Bancorp, Inc.— On January 28, 2026, the Company and Stellar Bancorp, Inc. (“Stellar”) jointly announced the signing of a definitive merger agreement whereby Stellar, the parent company of Stellar Bank (“Stellar Bank”), will merge with and into the Company and Stellar Bank will merge with and into the Bank. Stellar Bank operates 52 banking offices in greater Houston and Beaumont, Texas and surrounding areas. Under the terms and subject to the conditions of the definitive agreement, the Company will issue 0.3803 shares of its common stock and $11.36 in cash for each outstanding share of Stellar common stock. Based on the closing price of the Company’s common stock of $72.90 on January 27, 2026, the total consideration was valued at approximately $2.00 billion. The transaction is subject to customary closing conditions, including the receipt of regulatory approvals.