EXHIBIT 99.1 SOUTHSIDE BANCSHARES, INC. ANNOUNCES FINANCIAL RESULTS FOR THE FIRST QUARTER ENDED MARCH 31, 2025 Tyler, Texas (April 29, 2025) Southside Bancshares, Inc. ("Southside" or the "Company") (NYSE: SBSI) today reported its financial results for the quarter ended March 31, 2025. Southside reported net income of $21.5 million and earnings per diluted common share of$0.71 for both of the three month periods ended March 31, 2025 and 2024. The annualized return on average shareholders' equity for the th ...