EXHIBIT 99.1 COLUMBIA BANKING SYSTEM, INC. REPORTS FIRST QUARTER 2025 RESULTS $87 million$140 million $0.41$0.67 Net income Operating net income Earnings per diluted common share Operating earnings per diluted common share 1 1 CEO Commentary "Our consistent, repeatable performance in 2024 carried through to the first quarter of 2025," said Clint Stein, President and CEO. "Although the global environment is rife with uncertainty, our operations remain steadfast. Our consistent approach to banking is a key ...