Exhibit 99.1

FOR IMMEDIATE RELEASE

October 26, 2017

                        

Columbia Banking System Announces Third Quarter 2017 Results

Highlights

TACOMA, Washington, October 26, 2017 -- 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 third quarter 2017 earnings, “I’m very pleased with our financial performance this quarter. As evidenced by the growth in both loans and deposits, our financial results reflect the commitment of our bankers to build durable long-term relationships that lead to sustainable revenue streams.”

Balance Sheet

Total assets at September 30, 2017 were $9.81 billion , an increase of $129.5 million from June 30, 2017 . Loans grew $88.9 million during the quarter due to strong loan originations of $255.2 million . Securities available for sale were $2.21 billion at September 30, 2017 , a decrease of $56.8 million , or 3% from $2.26 billion at June 30, 2017 . Total deposits at September 30, 2017 were $8.34 billion , an increase of $269.3 million from June 30, 2017 . Core deposits comprised 96% of total deposits and were $8.00 billion at September 30, 2017 , an increase of $277.7 million from June 30, 2017 . The average cost of total deposits for the quarter was 0.05% , unchanged from the second quarter of 2017 .

Income Statement

Net Interest Income

Net interest income for the third quarter of 2017 was $88.9 million , an increase of $2.8 million from the linked period and an increase of $3.4 million from the prior year period. The linked quarter increase was principally from loan interest income, driven by both higher rates and higher volumes for the quarter. This increase was partially offset by a decrease in incremental accretion from purchased loans, which was $234 thousand lower than the linked period. The increase from the prior year period was also due to higher loan interest income, driven principally by higher loan volumes, partially offset by lower incremental accretion. Incremental accretion income from purchased loans in the current period was $1.7 million lower than the prior year period. For additional information regarding net interest income, see the “Average Balances and Rates” table.

Noninterest Income

Noninterest income was $37.1 million for the third quarter of 2017 , an increase of $12.9 million compared to $24.1 million for the second quarter of 2017 . The linked quarter increase was principally due to the $14.0 million gain on the sale of the merchant card services portfolio. As a result of that sale, we now share with the buyer in merchant services revenue and include such amounts in "Card revenue." For the current quarter, this net revenue share was $438 thousand. Compared to the third quarter of 2016 , noninterest income increased by $13.9 million due to the previously noted $14.0 million gain on sale of the merchant card services portfolio as well as higher other noninterest income, principally from a current quarter BOLI benefit of $1.0 million, with no such BOLI benefit in the prior year period.

Noninterest Expense

Total noninterest expense for the third quarter of 2017 was $67.5 million , a decrease of $1.3 million from the second quarter of 2017 . The small improvement resulted from the $2.4 million charge from early termination of our FDIC loss-sharing agreements recorded in the linked quarter; the early termination charge was recognized in other noninterest expense. The decrease was partially offset by higher compensation expense in the current quarter.

Compared to the third quarter of 2016 , noninterest expense was relatively unchanged. Increases in compensation and employee benefits and legal and professional fees were offset by decreases in advertising and promotion and merchant processing expenses. With respect to the latter, beginning July 1, 2017, the Company no longer directly incurs such costs.

Net Interest Margin

Columbia’s net interest margin (tax equivalent) for the third quarter of 2017 was 4.20% , an increase of 8 basis points from the linked quarter and an increase of 7 basis points from the prior year period. The increase from the linked quarter was due to higher yields on loans as a result of higher underlying rates. The increase from the prior year quarter was also due to higher yield on loans as well as higher loan volumes, partially offset by lower incremental accretion. Columbia’s operating net interest margin (tax equivalent) ⁽¹⁾ was 4.15% for the third quarter of 2017 , an increase of 6 basis points from the linked quarter and an increase of 12 basis points from the prior year period due to higher loan yields and volumes.

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

Asset Quality

At September 30, 2017 , nonperforming assets to total assets were 0.45% compared to 0.42% at June 30, 2017 and 0.35% at December 31, 2016 . Total nonperforming assets increased $3.1 million from the linked quarter due to a $3.5 million increase in nonaccrual loans, partially offset by a decrease in other real estate owned.

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 losses to period end loans was 1.10% at September 30, 2017 compared to 1.14% at June 30, 2017 . For the third quarter of 2017 , Columbia recorded a net provision recovery for loan and lease losses of $648 thousand compared to a net provision of $3.2 million for the linked quarter and $1.9 million for the comparable quarter last year. The net provision recovery for loan and lease losses recorded during the current quarter consisted of $175 thousand of net provision recovery for loan losses for loans, excluding PCI loans, and a provision recovery of $473 thousand for PCI loans.

Andy McDonald, Columbia’s Executive Vice President and Chief Credit Officer, commented, “For the third quarter our credit metrics remained stable and our loss rates continued to be exceptionally low, thus allowing us to recapture provision for the quarter.”

Organizational Update

Mr. Robbins commented, “We are pleased to share the successful completion of our transition to the new Columbia Connect online banking platform. The new system launched in July, providing customers with expanded mobile and tablet access while paving the way for future enhancements including bank to bank transfers, customer to customer transfers and a personal financial management suite. We are also looking forward to the upcoming close of our merger with Pacific Continental Corporation on November 1, 2017. Teams at both banks have been working diligently to prepare a smooth transition for clients and employees. As a combined organization, we will continue to provide the customer-focused approach to banking that has been the hallmark of both brands.”

Conference Call Information

Columbia’s management will discuss the third quarter 2017 results on a conference call scheduled for Thursday, October 26, 2017 at 1:00 p.m. Pacific Time (4:00 p.m. ET) . Interested parties may join the live-streamed event and a replay of the event by using the site:

https://engage.vevent.com/rt/columbiabankingsystemincao~94426798

The conference call can also be accessed on Thursday, October 26, 2017 at 1:00 p.m. Pacific Time (4:00 p.m. ET) by calling 888-286-8956; Conference ID code #94426798.

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 eleventh consecutive year, the bank was named in 2017 as one of  Puget Sound Business Journal's  "Washington's Best Workplaces." Columbia ranked in the top 30 on the 2017  Forbes  list of best banks.

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, including 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) legislation or regulatory requirements or changes may adversely affect the businesses in which Columbia is engaged; and (7) the proposed merger with Pacific Continental Corporation (“Pacific Continental”) may not close when expected or at all because conditions to closing are not satisfied on a timely basis or at all, which may have an effect on the trading prices of Columbia’s stock. 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.

Additional Information

In connection with the Agreement and Plan of Merger, dated as of January 9, 2017, by and between Columbia Banking System, Inc. and Pacific Continental, Columbia has filed with the SEC a Registration Statement on Form S-4 that includes a Joint Proxy Statement of Columbia and Pacific Continental and a Prospectus of Columbia, as well as other relevant documents concerning the proposed transaction. Shareholders of Columbia and Pacific Continental are urged to carefully read the Registration Statement and the Joint Proxy Statement/Prospectus regarding the transaction in their entirety and any other relevant documents filed with the SEC, as well as any amendments or supplements to those documents, because they contain important information. Shareholders of Columbia and Pacific Continental are also urged to carefully review and consider each of Columbia’s and Pacific Continental’s public filings with the SEC, including but not limited to their Annual Reports on Form 10-K, their proxy statements, their Current Reports on Form 8-K and their Quarterly Reports on Form 10-Q. A definitive Joint Proxy Statement/Prospectus has been sent to the shareholders of each institution seeking any required shareholder approvals. The Joint Proxy Statement/Prospectus and other relevant materials filed with the SEC may be obtained free of charge at the SEC’s Website at http://www.sec.gov. PACIFIC CONTINENTAL AND COLUMBIA SHAREHOLDERS ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND THE OTHER RELEVANT MATERIALS BECAUSE THEY CONTAIN IMPORTANT INFORMATION ABOUT THE TRANSACTION.

Investors will also be able to obtain these documents, free of charge, from Pacific Continental by accessing Pacific Continental’s website at www.therightbank.com under the link “Investor Relations” or from Columbia at www.columbiabank.com under the tab “About” and then under the heading “Investor Relations.” Copies can also be obtained, free of charge, by directing a written request to Columbia, Attention: Corporate Secretary, 1301 A Street, Suite 800, Tacoma, Washington 98401-2156 or to Pacific Continental, Attention: Corporate Secretary, 111 West Seventh Avenue, P.O. Box 10727, Eugene Oregon 97440-2727.