Natural Combination of the Western Region’s Leading Business Banks Builds Market Presence and Drives Financial Performance

TACOMA, Wash. and IRVINE, Cal., April 23, 2025/PRNewswire/ -- Columbia Banking System, Inc. ("Columbia") (Nasdaq: COLB), the parent company of Umpqua Bank, and Pacific Premier Bancorp, Inc. ("Pacific Premier") (Nasdaq: PPBI), the parent company of Pacific Premier Bank, National Association, jointly announced today that they have entered into a definitive merger agreement, pursuant to which Columbia will acquire Pacific Premier in an all-stock transaction. The combined company will have approximately $70 billion in assets and will be a market leader in the largest banking markets within the Western U.S.

Clint Stein, President, CEO, and Director of Columbia, said, "This combination truly establishes the leading banking franchise in the Western region. It is a natural and strategic fit that strengthens our competitive position in Southern California, enhances our service offerings, and elevates our performance. We are pleased to welcome Pacific Premier’s clients, employees, and stockholders to Columbia and are excited for what we will accomplish together for the benefit of all of our stakeholders and the communities we serve."

Steve Gardner, Chairman, President, and CEO of Pacific Premier, said, “We have worked tirelessly for more than two decades to build a strong franchise at Pacific Premier. We are thrilled to have the opportunity to join Columbia, a company whose culture, business model, and credit discipline align with our own. The combination of these two companies operating in growing markets provides a great opportunity for our teams to continue to deliver high-quality, relationship-based banking products, services, and expertise to our clients, and to continue to generate long-term value for our stockholders.”

Pursuant to the terms of the definitive merger agreement, Pacific Premier stockholders will receive 0.9150 of a share of Columbia common stock for each Pacific Premier share they own. The merger is valued at approximately $2.0 billion, or $20.83 per Pacific Premier share, based on Columbia’s closing stock price of $22.77 on April 22, 2025. Following closing, Pacific Premier stockholders will own approximately 30% of Columbia’s outstanding shares of common stock. Three Pacific Premier directors, including Steve

Gardner and two other current Pacific Premier directors to be mutually agreed by Columbia and Pacific Premier, will join the Columbia board upon the completion of the transaction. The definitive merger agreement was unanimously approved by the Boards of Directors of Columbia and Pacific Premier.