Columbia Banking System, Inc. (COLB Quick QuoteCOLB - Free Report) is moving through the heavy-lift phase of its Pacific Premier integration, and the next few quarters should reveal how quickly deal benefits turn into cleaner earnings. The bank reflects a balanced setup with tangible synergy progress but lingering near-term costs. 

For investors, “integration milestones” matter because they are the checkpoints that convert a strategic footprint expansion into measurable efficiency and revenue durability. In this case, the key goalposts are the bank’s cost synergy targets, completed conversion work, and the new fee capabilities added through the transaction.

COLB Integration Timeline

Columbia Banking closed its acquisition of Pacific Premier on Aug. 31, 2025, a deal that completed its Western footprint and strengthened its positioning in Southern California. That footprint expansion is the strategic backdrop, but the investment debate is now centered on execution. 

Integration milestones in this story are practical and measurable. They include hitting cost-savings run rates, finishing system and branch actions that unlock operating leverage, and translating a broader product set into more recurring fee income.

Columbia Banking’s Cost Synergy Target and Progress

The bank has targeted $127 million in annualized cost savings from the Pacific Premier transaction. By the end of 2025, it had realized $63 million of that total, giving investors a concrete marker to track the remaining runway. 

Management has also framed the timing clearly. The company expects to realize the previously disclosed cost savings by June 30, 2026, setting a defined window for when synergy benefits should show up more consistently in the expense base.

A major milestone arrived in the first quarter of 2026, when COLB completed system conversions and branch consolidations tied to the integration. With the conversion work done, subsequent quarters should provide a clearer view of how quickly run-rate efficiencies can build.

Columbia Banking’s New Fee Platforms From the Deal

Beyond cost actions, Pacific Premier broadened Columbia Banking’s fee toolkit. The combined company added fee platforms including Custodial Trust Services, homeowners association banking, escrow, and 1031 exchanges.  That expansion is notable because it extends the franchise beyond spread-driven banking into services that can deepen relationships and diversify revenue.

Early commercial activity points to traction. Since closing, the company has generated more than 1,200 cross-sell referrals, and de novo and campaign efforts produced meaningful deposit inflows through mid-October.  Over time, management expects the broader product set and referral activity to support higher wallet share and a gradual shift toward more durable core fee streams.

COLB Expense Run Rate and Near-Term Margin Effects

Near term, expenses remain elevated, reflecting integration and amortization costs, along with purchase accounting effects that can add noise to reported performance. That is why efficiency and returns can look pressured even when synergy milestones are being met.

Management expects operating expenses, excluding core deposit intangible amortization, to run $330-$340 million per quarter for the next several quarters. Until system synergies fully offset integration costs, expense optics are likely to stay choppy, which can influence how quickly improvements in profitability filter into bottom-line momentum.

Columbia Banking’s Bottom-Line Debate

The long-term setup rests on execution. Management expects NIM expansion through 2026, and external models point to multi-year earnings per share growth through 2026-2027 tied to synergy realization and balance sheet mix shifts. 

The counterweight is near-term noise. Integration and amortization costs, one-time purchase accounting effects, and competitive deposit pricing pressure can cloud quarterly comparisons even if underlying momentum is improving. 

COLB carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

Over the past year, shares of Columbia Banking have gained 27.2% compared with the industry’s rise of 20.2%.

Price Performance

Image Source: Zacks Investment Research

COLB Peer Context

Among Columbia Banking Western peers, East West Bancorp (EWBC Quick QuoteEWBC - Free Report) and Western Alliance (WAL Quick QuoteWAL - Free Report) each has a Zacks Rank #3. 

East West Bancorp is a Pasadena-based commercial bank with more than 110 locations across the U.S. and Asia, often cited for cross-border and relationship banking depth in Western markets. Western Alliance, headquartered in Phoenix, operates full-service business banking divisions in Arizona, California and Nevada, alongside specialized national units, offering a helpful read-through on Western deposit and C&I dynamics.