Columbia Banking’s $2.4B Acquisition Drives 0.97 Surge and $390M Trading Volume Rank 289 as Regional Dominance Grows

On September 2, 2025, Columbia Banking System (COLB) rose 0.97% to close with a trading volume of $390 million, ranking 289th in market activity. The stock’s performance coincided with the completion of its $2.4 billion acquisition of Pacific Premier Bancorp, a pivotal move to consolidate its regional dominance in Western U.S. markets.

The merger, finalized after months of strategic planning, expanded Columbia’s asset base to $70 billion, with $50 billion in loans and $56 billion in deposits. The combined entity now operates over 350 branches across eight states, including California, Washington, and Arizona, significantly enhancing its footprint in Southern California. The integration of Pacific Premier’s systems is slated for Q1 2026, with former Pacific Premier executives joining Columbia’s board to oversee the transition.

Columbia also completed its rebranding initiative, unifying all operations under the Columbia Bank name. This move aims to streamline customer recognition and marketing efforts, following the dissolution of the Umpqua Bank brand. Leadership integration included the appointment of Pacific Premier’s former CEO Steve Gardner as a non-executive board director, alongside two additional executives, to ensure continuity in strategic oversight.

The acquisition accelerates Columbia’s decade-long expansion plans in key western markets, solidifying its position as a top regional bank. With enhanced geographic diversification and operational scale, the company is positioned to leverage cross-selling opportunities while maintaining cost efficiencies. The transaction’s share exchange ratio granted former Pacific Premier shareholders approximately 30% ownership in the combined entity, aligning long-term incentives between stakeholders.

Backtested results indicate that the transaction’s structural design and integration timeline align with Columbia’s stated objectives of minimizing operational disruptions while maximizing growth potential in high-priority markets.