PROSPERITY BANCSHARES, INC.® COMPLETES MERGER WITH SOUTHWEST BANCSHARES, INC.

Core Viewpoint - Prosperity Bancshares, Inc. has successfully completed the merger with Southwest Bancshares, Inc. and its subsidiary Texas Partners Bank, effective February 1, 2026, enhancing its market presence in Texas [1][2]. Group 1: Merger Details - The merger agreement resulted in Prosperity issuing 4,095,397 shares of common stock to former shareholders and award holders of Southwest [2]. - Texas Partners operates 11 banking offices in Central Texas, including San Antonio, and will continue to use its name until operational integration, expected by November 2026 [4]. Group 2: Management Changes - Brent Given, the Interim Chairman and CEO of Texas Partners, will become the San Antonio Area Chairman at Prosperity Bank, while Tom Moreno will take a senior management role [3]. - Additional Texas Partners management will retain leadership positions within the combined organization, and Gene Dawson, Jr. has joined the Board of Directors of Prosperity Bank [3]. Group 3: Company Overview - As of December 31, 2025, Prosperity Bancshares is a regional financial holding company with assets of $38.463 billion, providing a range of banking services across Texas and Oklahoma [5]. - Prosperity operates 301 full-service banking locations across various regions, including Houston, Dallas/Fort Worth, and Central Texas [6].