Exhibit 99.1

FOR IMMEDIATE RELEASE

April 25, 2019

                        

Columbia Banking System Announces First Quarter 2019 Results,

Quarterly and Special Cash Dividends

Highlights

TACOMA, Washington, April 25, 2019 -- Hadley Robbins, President and Chief Executive Officer of Columbia Banking System and Columbia Bank (NASDAQ: COLB) (“Columbia”), said today upon the release of Columbia’s first quarter 2019 earnings, “I would like to take this opportunity to express my appreciation for the high level of collaboration and commitment of our employees in creating value for our customers and shareholders. Their collective efforts represent the most significant catalyst in generating the record level of net income and earnings per share posted in the first quarter.”

__________

(1) Operating net interest margin (tax equivalent) is a non-GAAP measure. See the section titled "Non-GAAP Financial Measures" in this earnings release for the reconciliation of operating net interest margin (tax equivalent) to net interest margin.

Balance Sheet

Total assets at March 31, 2019 were $13.06 billion . Loans were $8.52 billion , up $129.3 million , or 6.2% annualized, from December 31, 2018 as a result of loan originations of $365.8 million . Securities available for sale were $3.03 billion at March 31, 2019 , a decrease of $140.2 million from $3.17 billion at December 31, 2018 as earning assets rotated into loans. Total deposits at March 31, 2019 were $10.37 billion , a decrease of $89.1 million from December 31, 2018 . Core deposits comprised 95% of total deposits and were $9.90 billion at March 31, 2019 , a decrease of $74.9 million from December 31, 2018 . Deposit mix remained fairly consistent from December 31, 2018 with 49% noninterest-bearing and 51% interest-bearing. The average cost of total deposits for the quarter was 18 basis points, an increase of 4 basis points from the fourth quarter of 2018 , on an actual/actual basis. For additional information regarding this calculation, see the “Net Interest Margin” section.

Clint Stein, Columbia’s Executive Vice President and Chief Operating Officer, stated, “We achieved record loan production for the first quarter which, coupled with moderating headwinds from pay down activity, led to very solid loan growth during the quarter. Our bankers continue to take market share and earn new relationships on both sides of the balance sheet.” Mr. Stein continued, “Our typical seasonal decline in deposits masked the significant new business development wins our teams achieved.”

Income Statement

Net Interest Income

Net interest income for the first quarter of 2019 was $121.0 million , a decrease of $2.9 million from the linked quarter and an increase of $5.5 million from the prior year period. The decrease from the linked quarter was primarily due to higher average Federal Home Loan Bank (“FHLB”) advance balances combined with a nominal increase in the rates on our interest-bearing demand and money market accounts. The increase from the prior year period was a combination of higher rates on earning assets and higher volumes of loans and taxable securities. For additional information regarding net interest income, see the “Net Interest Margin” section and the “Average Balances and Rates” tables.

Noninterest Income

Noninterest income was $21.7 million for the first quarter of 2019 , an increase of $1.3 million from the fourth quarter of 2018 . The linked quarter increase was principally due to the $1.8 million gain from the sale of securities during the quarter. Compared to the first quarter of 2018 , noninterest income decreased $1.4 million . The decrease from the prior year period was due to lower card revenue during the current quarter because, as of July 1, 2018, we became subject to the interchange fee cap imposed under

the Dodd-Frank Act. In addition, loan revenue decreased compared to the first quarter of 2018 due to lower gains recorded on the sale of SBA loans coupled with lower interest rate swap fee income. Other noninterest income also declined as a result of a gain on the sale of a credit card portfolio that was recorded during the first quarter of 2018. Partially offsetting these decreases was the previously noted $1.8 million of investment securities gains in the current quarter.

Noninterest Expense

Total noninterest expense for the first quarter of 2019 was $84.7 million , a decrease of $2.3 million from the fourth quarter of 2018 . After removing the effect of acquisition-related expenses for the linked quarter, noninterest expense decreased $1.8 million due to lower legal and professional fees and other expenses which were partially offset by an increase in compensation and benefits expense. The decrease in legal expense was due to lower expenses related to problem loans, while professional fees declined as a result of lower expenses related to corporate initiatives during the first quarter. Other expenses decreased as a result of a $550 thousand recapture of the loan loss reserve on off-balance sheet liabilities during the quarter compared to an expense of $375 thousand during the linked quarter.

Compared to the first quarter of 2018 , noninterest expense decreased by $1.3 million . After removing the acquisition-related expenses of $4.3 million from the first quarter of 2018, year over year noninterest expense increased $3.0 million , or 4%. This increase was primarily driven by higher compensation and employee benefits and legal and professional expenses partially offset by a decrease in other expenses. Other expenses decreased as a result of a $550 thousand recapture of the loan loss reserves on off-balance sheet liabilities during the quarter compared to an expense of $1.2 million during the first quarter of 2018.

Net Interest Margin

Beginning first quarter 2019, net interest margin was calculated using the actual number of days and on an Actual/Actual basis. This change was done to provide more meaningful trend information, on a quarterly basis, for our net interest margin regardless of the number of days in the quarter. Prior periods, which were previously reported on a 30/360 basis, have been restated to conform to the current basis.

Columbia’s net interest margin (tax equivalent) for the first quarter of 2019 was 4.32% , a decrease of 4 basis points from the linked quarter and an increase of 4 basis points from the prior year period. The decrease in the net interest margin for the current quarter as compared to the linked quarter was due to higher average FHLB advance balances combined with lower loan discount accretion income during the quarter. The increase from the prior year period was a combination of higher rates paid on loans and taxable securities and higher volumes of these interest-earning assets partially offset by higher average FHLB advances.

Columbia’s operating net interest margin (tax equivalent) ⁽²⁾ was 4.33% for the first quarter of 2019 , which was effectively flat compared to the linked quarter and increased 9 basis points from the prior year period. The increase in the operating net interest margin for the current quarter compared to the prior year quarter was due to higher rates on interest-earning assets, which more than offset the increase in rates on interest-bearing liabilities.

Greg Sigrist, Columbia’s Executive Vice President and Chief Financial Officer, commented, “Our client franchise has continued to be a remarkable source of strength, as reflected in our total deposit cost.”

The following table shows the impact to interest income resulting from income accretion on acquired loan portfolios as well as the net interest margin and operating net interest margin:

(1) Beginning January 2019, net interest margin (tax equivalent) and operating net interest margin (tax equivalent) were calculated using the actual number of days on an Actual/Actual basis. This change was done to provide more meaningful trend information, on a quarterly basis, for our net interest margin regardless of the number of days in the quarter. Prior periods, which were previously reported on a 30/360 basis, have been restated to conform to the current basis.

(2) Operating net interest margin (tax equivalent) is a non-GAAP financial measure. See the section titled “Non-GAAP Financial Measures” in this earnings release for the reconciliation of operating net interest margin (tax equivalent) to net interest margin.

Asset Quality

At March 31, 2019 , nonperforming assets to total assets were 0.45% compared to 0.46% at December 31, 2018 . Total nonperforming assets decreased $2.2 million from the linked quarter due to a decrease in nonaccrual loans.

Andy McDonald, Columbia’s Executive Vice President and Chief Credit Officer, commented, “It was a stable quarter for the bank from a credit perspective as nonperforming assets to total assets ticked down to 0.45% which is below our general target of 0.50%. We continued to have modest net charge-offs and provisions for loan losses.”

The following table sets forth information regarding nonaccrual loans and total nonperforming assets:

The following table provides an analysis of the Company’s allowance for loan and lease losses:

The allowance for loan and lease losses to period end loans was 0.98% at March 31, 2019 compared to 0.99% at December 31, 2018 . For the first quarter of 2019 , Columbia recorded a net provision for loan and lease losses of $1.4 million compared to a net provision of $1.8 million for the linked quarter and a net provision of $5.9 million for the comparable quarter last year. The net provision for loan and lease losses recorded during the current quarter consisted of $1.3 million of provision expense for loans, excluding PCI loans and a provision of $18 thousand for PCI loans.

Organizational Update

As described in our Annual Report on Form 10-K for the year ended December 31, 2018, our Board of Directors recently approved a stock repurchase program for up to 2.9 million shares, or approximately 4% of outstanding stock.

“Columbia is committed to driving long term shareholder value, and we believe that having a share repurchase program as part of our capital strategy increases the options we have available to achieve this goal,” said Hadley Robbins, President and Chief Executive Officer.

During the quarter, Columbia Bank’s Board of Directors was recognized by Seattle Business Magazine with its “Governance Award” for their service to the bank and the community. In addition, we were pleased to be recognized as one of the “Best Places to Work in Idaho” by Populus Marketing Research.

Cash Dividend Announcement

Columbia will pay a regular cash dividend of $0.28 per common share and a special cash dividend of $0.14 per common share on May 22, 2019 to shareholders of record as of the close of business on May 8, 2019 .

Conference Call Information

Columbia’s management will discuss the first quarter 2019 financial results on a conference call scheduled for Thursday, April 25, 2019 at 10:00 a.m. Pacific Daylight Time (1:00 p.m. EDT) . Interested parties may join the live-streamed event by using the site:

https://engage.vevent.com/rt/columbiabankingsysteminc~042519

The conference call can also be accessed on Thursday, April 25, 2019 at 10:00 a.m. Pacific Daylight Time (1:00 p.m. EDT) by calling 888-286-8956; Conference ID: 6052807.

A replay of the call can be accessed beginning Friday, April 26, 2019 using the site:

https://engage.vevent.com/rt/columbiabankingsysteminc~042519

About Columbia

Headquartered in Tacoma, Washington, Columbia Banking System, Inc. is the holding company of Columbia Bank, a Washington state-chartered full-service commercial bank with locations throughout Washington, Oregon and Idaho. For the 12th consecutive year, the bank was named in 2018 as one of  Puget Sound Business Journal's “Washington’s Best Workplaces.” For the 8th consecutive year, Columbia was included in the 2019 Forbes America’s Best Bank list.

More information about Columbia can be found on its website at www.columbiabank.com .

Note Regarding Forward-Looking Statements

This news release includes forward looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward looking statements include, but are not limited to, descriptions of Columbia’s management’s expectations regarding future events and developments such as future operating results, growth in loans and deposits, continued success of Columbia’s style of banking and the strength of the local economy. The words “will,” “believe,” “expect,” “intend,” “should,” and “anticipate” or the negative of these words or words of similar construction are intended in part to help identify forward looking statements. Future events are difficult to predict, and the expectations described above are necessarily subject to risks and uncertainties, many of which are outside our control, that may cause actual results to differ materially and adversely. In addition to discussions about risks and uncertainties set forth from time to time in Columbia’s filings with the Securities and Exchange Commission, available at the SEC’s website at www.sec.gov and the Company’s website at www.columbiabank.com , include the “Risk Factors,” “Business” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of our annual reports on Form 10-K and quarterly reports on Form 10-Q, (as applicable), factors that may cause actual results to differ materially from those contemplated by such forward-looking statements include, among others, the following: (1) local, national and international economic conditions may be less favorable than expected or have a more direct and pronounced effect on Columbia than expected and adversely affect Columbia’s ability to continue its internal growth at historical rates and maintain the quality of its earning assets; (2) changes in interest rates could significantly reduce net interest income and negatively affect funding sources; (3) projected business increases following strategic expansion or opening or acquiring new branches may be lower than expected; (4) costs or difficulties related to the integration of acquisitions may be greater than expected; (5) competitive pressure among financial institutions may increase significantly; (6) failure to maintain effective internal controls over financial reporting or disclosure controls and procedures may adversely affect our business; (7) reliance on and cost of technology may increase; and (8) legislation or regulatory requirements or changes may adversely affect the businesses in which Columbia is engaged. We believe the expectations reflected in our forward-looking statements are reasonable, based on information available to us on the date hereof. However, given the described uncertainties and risks, we cannot guarantee our future performance or results of operations and you should not place undue reliance on these forward-looking statements which speak only as of the date hereof. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by the federal securities laws. The factors noted above and the risks and uncertainties described in our SEC filings should be considered when reading any forward-looking statements in this release.

(1) Beginning the first quarter of 2019, B&O taxes were reported separately from other taxes, licenses and fees, which are now reported under “other noninterest expense.” Prior periods have been reclassified to conform to current period presentation.

(1) This is a non-GAAP measure. See section titled "Non-GAAP Financial Measures" on the last three pages of this earnings release for a reconciliation to the most comparable GAAP measure.

(2) Beginning January 2019, net interest margin was calculated using the actual number of days and on an Actual/Actual basis. This change was done to provide more meaningful trend information, on a quarterly basis, for our net interest margin regardless of the number of days in the quarter. Prior periods, which were previously reported on a 30/360 basis, have been restated to conform to the current basis.

(3) Noninterest expense divided by the sum of net interest income on a tax equivalent basis and noninterest income on a tax equivalent basis.