Columbia Bank Issues $250M Subordinated Notes for Capital Restructuring
KBRA rates the new issuance A- with a Stable Outlook, noting that proceeds will retire trust preferred securities at Columbia Banking System while maintaining a strong deposit base.
Columbia Bank has issued $250 million in subordinated notes with a final maturity date of September 18, 2036. KBRA has assigned the instrument an A- rating with a Stable Outlook, reflecting the bank's solid multi-year performance record. The notes become callable at the bank's option starting September 18, 2031, providing flexibility for future capital management.
Net proceeds from the issuance are designated for general corporate purposes and the retirement of outstanding trust preferred securities at the holding company, Columbia Banking System, Inc. (NASDAQ: COLB). This transaction effectively shifts capital from the holding company level to the bank, altering the composition of the regulatory capital stack while addressing legacy debt structures.
Deposit Base Anchors Net Interest Margin
The credit rating relies heavily on the bank’s attractive deposit composition, which serves as the primary driver of its net interest margin (NIM). In the second quarter of 2026, consolidated NIM remained strong at 3.93%, with the bank-level performance slightly outpacing the consolidated figure. Noninterest-bearing deposits, a key cost advantage, accounted for 33% of total deposits during this period, demonstrating remarkable stability in the funding mix.
This rich deposit base underpins bottom-line earnings, allowing the institution to maintain competitive margins despite broader market interest rate dynamics. The stability of these low-cost funds provides a durable advantage over peers that rely more heavily on wholesale funding or interest-bearing liabilities, supporting the A- rating assigned by KBRA.
Capital Ratios Face Modest Reduction
Columbia Banking System’s capital ratios were essentially unchanged on a linked-quarter basis, as shareholder distributions, including common dividends and share repurchases, exceeded quarterly net income. These outflows were offset by a modest decline in total assets. However, the new subordinated notes issuance, combined with the repayment of trust preferred securities whose proceeds were previously contributed as common equity, will result in a modest reduction in the bank's capital ratios.
The shift from trust preferred securities to subordinated debt represents a change in the hierarchy of claims within the capital structure. While the total capital amount may remain similar, the specific composition changes, impacting how regulators and rating agencies view the quality of the capital buffer. KBRA notes that the bank’s ability to rebuild capital remains a key factor in maintaining its current standing.
Rating Sensitivities and Future Outlook
Positive rating action is considered unlikely in the intermediate term due to the company's high position within KBRA's rated universe. Conversely, negative pressure could emerge if the gap between Columbia Bank’s consolidated capital ratios and those of rated peers widens significantly. This risk is heightened if the bank’s ability to rebuild capital is viewed as uncertain or limited.
A significant deterioration in asset quality, leading to elevated credit costs and material pressure on earnings, would also trigger negative rating action. The stability of the A- rating thus depends on continued strong earnings generation, stable deposit funding, and the maintenance of capital levels relative to industry peers.
