Exhibit 99.1

NEWS RELEASE

FOR IMMEDIATE RELEASE

Pacific Continental Corporation Reports Record Net Income

Continued balance sheet expansion and earnings growth provide solid momentum toward merger with Columbia Bank

EUGENE, Ore., January 26, 2017 – Pacific Continental Corporation (Nasdaq: PCBK), the holding company of Pacific Continental Bank, today reported financial results for the fourth quarter and year ended December 31, 2016.

Fourth Quarter 2016 Highlights:

Full Year 2016 Highlights:

Merger Update

On January 9, 2017, Pacific Continental Corporation entered into a definitive agreement to merge with Columbia Banking System, Inc., headquartered in Tacoma, Washington. Upon completion of the merger, the combined company will operate under the Columbia Bank name and brand. The agreement was approved by the Board of Directors of each company. Closing of the transaction, which is expected to occur in mid-2017, is contingent on shareholder approval and receipt of necessary regulatory approvals, along with satisfaction of other customary closing conditions.

Net Income Highlights

Net income for the fourth quarter 2016 was a record $6.9 million, or $0.30 per diluted share. Included in our net income were non-core costs associated with our acquisition of Foundation Bank of approximately $1.2 million, or approximately $0.03 per diluted share. Additionally, we incurred $250 thousand of legal expenses associated with our recent merger announcement with Columbia Bank. The provision for loan losses expense in the fourth quarter was $1.9 million, compared to $1.4 million for the third quarter. Annualized returns on average assets, average equity and average tangible equity for fourth quarter 2016 were 1.08%, 9.93%, and 13.35%, respectively, compared to 0.89%, 8.05%, and 10.14% for third quarter 2016.

Net income for the full year 2016 was a record $19.8 million, or $0.95 per diluted share, compared to $18.8 million, or $0.97 per diluted share for the full year 2015. Included in net income was $4.9 million of pre-tax non-core costs associated with our acquisition of Foundation Bank, compared to $1.8 million of pre-tax non-core expenses incurred in

2015 related to our acquisition of Capital Pacific Bank. Returns on average assets, average equity and average tangible equity for the full year 2016 were 0.92%, 8.23%, and 10.5%, respectively, compared to 1.05%, 8.99%, and 11.14% for full year 2015.

“I am extremely proud of our entire team on a successful 2016, which included record net income, the successful acquisition and integration of Foundation Bank, and double-digit organic loan growth”, said Roger Busse, chief executive officer. “Our 2016 accomplishments illustrate the legacy of Pacific Continental Bank: outstanding results driven by outstanding people. This should provide solid momentum as we move towards our merger with Columbia Bank.”

Fourth quarter 2016 noninterest income was $2.3 million, an increase of $423 thousand from the third quarter 2016. Approximately $327 thousand of the increase related to gains from the termination of several debt swap agreements that were “in the money” due to the recent increase in long-term rates. The remainder of the increase related primarily to the additional service charge on deposits of Foundation Bank clients.

Noninterest expense for the fourth quarter 2016 was $15.8 million, which represented an increase of $2.0 million from the third quarter of 2016. The increase relates primarily to the acquisition of Foundation Bank, which occurred on September 6, 2016. The fourth quarter was the first full quarter of expenses related to the new office and additional employees acquired through the Foundation Bank acquisition. Additionally, we incurred $150 thousand of stock compensation expense related to the valuation of Stock Appreciation Rights and our increased market price during the fourth quarter. We also incurred $250 thousand of legal expenses related to our recently announced merger with Columbia Bank.

Net Interest Margin

The fourth quarter 2016 net interest margin was 4.38%, an increase of 16 basis points from the third quarter net interest margin. Accretion income for the fourth quarter 2016 was $2.2 million compared to $877 thousand for the third quarter 2016. As of December 31, 2016, there was $11.3 million fair value discount remaining on acquired loan portfolios. Accretion of loan fair value discount from our two prior acquisitions, in 2013 and 2015, and now the recent Foundation Bank acquisition, excluding any prepayments, are expected to add a minimum of $1.2 million in interest income during the first quarter of 2017, which would improve our reported margin by approximately 20 basis points. Monthly accretion is accounted for in accordance with GAAP with the majority using the interest-method however, prepayment or refinancing can accelerate monthly expected accretion income

The core net interest margin, which removes nonrecurring items and accretion of loan fair value marks, was 3.96% for the fourth quarter 2016 compared to 3.99% for the third quarter 2016. An outline of our core and reported net interest margins is as follows:

Balance Sheet Highlights

Gross loans grew by $51.1 million in the fourth quarter 2016, and totaled $1.86 billion at December 31, 2016. Gross loan growth through the full year 2016 was $453.3 million. Excluding the $270.5 million in loans acquired from our Foundation Bank acquisition, organic loan growth was $183.2 million, or 13.03%. At December 31, 2016, loans to dental practitioners totaled $377.5 million and represented 20.30% of the loan portfolio. This represented an increase of $7.3 million over third quarter 2016, when loans to dental practitioners represented 20.46% of the loan portfolio. For the full year 2016, loans to dental practitioners grew by $37.3 million, or 10.97%.

Period-end Company-defined core deposits at December 31, 2016, were $2.04 billion, a decrease of $14.3 million from the third quarter 2016. The decrease was in large part expected, as one client increased its deposits by $64.3 million at the end of the third quarter due to the sale of a business unit. During the fourth quarter this client decreased its deposits by $51.0 million.

Core deposit growth for the full year 2016 was $501.1 million. Excluding the $396.5 million in deposits acquired from Foundation Bank during the third quarter, our full year organic core deposit growth was $104.6 million, or 6.82%.

“Our 2016 results were yet another opportunity to demonstrate the outstanding work of our highly talented team of bankers,’ said Casey Hogan, chief operating officer. “Impressive organic loan growth and solid gains in the deposit portfolio should provide a robust tailwind heading into our merger with Columbia Bank.”

Asset Quality

As of December 31, 2016, the allowance for loan losses as a percentage of outstanding loans was 1.21%, an increase from the 1.14% reported at September 30, 2016. At December 31, 2016, the allowance for loan losses as a percentage of nonperforming loans, net of government guarantees, increased to 236.88% from 210.23% at September 30, 2016. During the fourth quarter 2016, the Company recorded net recoveries of $48 thousand, compared to net loan recoveries of $24 thousand during the third quarter 2016. During the fourth quarter, the Company made a $1.9 million provision for loan losses compared to a $1.4 million provision in the third quarter 2016. For the full year 2016, the Company made a $5.5 million provision for loan losses, compared to $1.7 million for the full year 2015.

At December 31, 2016, nonperforming assets, net of government guarantees, totaled $21.5 million, or 0.85% of total assets, compared to $22.8 million, or 0.90% of total assets, at September 30, 2016. Nonperforming assets at December 31, 2016, were comprised of $9.5 million of nonperforming loans, net of government guarantees of $2.4 million, and $12.1 million in other real estate owned. Loans past-due 30-89 days were 0.06% of total loans at December 31, 2016, compared to 0.01% of total loans at September 30, 2016.

Capital Adequacy

The Company’s consolidated capital ratios continued to be above the minimum thresholds for the FDIC’s “well-capitalized” designation. At December 31, 2016, the Company’s capital ratios were as follows:

Non-GAAP Financial Measures

In addition to results presented in accordance with generally accepted accounting principles (GAAP), this press release contains certain non-GAAP financial measures. The Company believes that such non-GAAP financial measures provide investors with information useful in understanding the Company’s financial performance; however, readers of this release are urged to review these non-GAAP financial measures in conjunction with the GAAP results as reported.

Certain financial measures such as tangible shareholders’ equity, and tangible assets, are considered non-GAAP measures. Management believes including non-GAAP measures along with GAAP measures provides investors with a broader understanding of capital adequacy, funding sources and revenue trends. Tangible shareholders’ equity is calculated as total shareholders’ equity less goodwill and core deposit intangible assets. Additionally, tangible assets are calculated as total assets less goodwill and core deposit intangible assets.

The following table presents a reconciliation of ending total shareholders’ equity (GAAP) to ending tangible shareholders’ equity (non-GAAP), and total assets (GAAP) to total tangible assets (non-GAAP):

About Pacific Continental Bank

Pacific Continental Bank, the wholly-owned operating subsidiary of Pacific Continental Corporation, delivers highly personalized services through fifteen banking offices in Oregon and Washington. The Bank also operates loan production offices in Tacoma, Washington and Denver, Colorado. Pacific Continental, with more than $2.5 billion in assets, has established one of the most unique and attractive metropolitan branch networks in the Pacific Northwest with offices in three of the region’s largest markets, including Seattle, Portland and Eugene. Pacific Continental targets the banking needs of community-based businesses, health care professionals, professional service providers and nonprofit organizations.

Since its founding in 1972, Pacific Continental Bank has been honored with numerous awards and recognitions from highly regarded third-party organizations including The Seattle Times, the Portland Business Journal, the Seattle Business magazine and Oregon Business magazine. A complete list of the company’s awards and recognitions –as well as supplementary information about Pacific Continental Bank –can be found online at www.therightbank.com. Pacific Continental Corporation’s shares are listed on the Nasdaq Global Select Market under the symbol “PCBK” and are a component of the Russell 2000 Index.

Forward-Looking Statement Safe Harbor

This release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (“PSLRA”). All statements other than statements of historical fact are forward looking statements. Forward-looking statements often use words such as “anticipates,” “targets,” “expects,” “estimates,” “intends,” “plans,” “goals,” “believes” and other similar expressions or future or conditional verbs such as “will,” “should,” “would” and “could.” The forward-looking statements made represent Pacific Continental’s current estimates, projections, expectations, plans or forecasts of its future results and revenues, including but not limited to statements about performance, loan or deposit growth, net interest margin compression, strategic focus, capital position, liquidity, credit quality, credit quality trends, fair value accretion, the impact and effects of recent or pending acquisitions and the benefits of the

business combination transaction involving Pacific Continental and Columbia, including future financial and operating results, and the combined company’s plans, objectives and expectations. These statements are not guarantees of future results or performance and involve certain risks, uncertainties and assumptions that are difficult to predict and are often beyond Pacific Continental’s control. Actual outcomes and results may differ materially from those expressed in, or implied by, any of these forward-looking statements. You should not place undue reliance on any forward-looking statement and should consider all of the following uncertainties and risks, as well as those more fully discussed under “Risk Factors”, “Business”, and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in Pacific Continental’s and Columbia’s most recent Annual Report on Form 10-K, Quarterly Report on Form 10-Q, and in any of Pacific Continental’s and Columbia’s subsequent SEC filings, including the high concentration of loans of the Company’s banking subsidiary in commercial and residential real estate lending and in loans to dental professionals; adverse economic trends in the United States and the markets we serve affecting the Bank’s borrower base; continued erosion or sustained low levels of consumer confidence; changes in the Federal Reserve’s monetary policies and the regulatory environment and increases in associated costs, particularly ongoing compliance expenses and resource allocation needs; vendor quality and efficiency; the Company’s ability to control risks associated with rapidly changing technology both from an internal perspective as well as for external providers; operational systems or infrastructure failures; increased competition; fluctuating interest rates; a tightening of available credit; the potential adverse impact of legal or regulatory proceedings; and risks related to the business combination transaction involving Pacific Continental and Columbia, including (i) the possibility that the merger does not close when expected or at all because required regulatory, shareholder or other approvals and other conditions to closing are not received or satisfied on a timely basis or at all; (ii) changes in Columbia’s stock price before closing, including as a result of the financial performance of Pacific Continental prior to closing, or more generally due to broader stock market movements, and the performance of financial companies and peer group companies; (iii) the risk that the benefits from the transaction may not be fully realized or may take longer to realize than expected, including as a result of changes in general economic and market conditions, interest and exchange rates, monetary policy, laws and regulations and their enforcement, and the degree of competition in the geographic and business areas in which Columbia and Pacific Continental operate; (iv) the ability to promptly and effectively integrate the businesses of Columbia and Pacific Continental; (v) the reaction to the transaction of the companies’ customers, employees and counterparties; (vi) diversion of management time on merger-related issues; (vii) lower than expected revenues, credit quality deterioration or a reduction in real estate values or a reduction in net earnings; and (viii) other risks that are described in Columbia’s and Pacific Continental’s public filings with the SEC. Pacific Continental Corporation undertakes no obligation to publicly revise or update any forward-looking statement to reflect the impact of events or circumstances that arise after the date of this release. This statement is included for the express purpose of invoking the PSLRA’s safe harbor provisions.

IMPORTANT INFORMATION FOR INVESTORS AND SHAREHOLDERS

This communication is being made in respect of the proposed merger transaction involving Columbia Banking System and Pacific Continental. This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such jurisdiction. In connection with the proposed transaction, Columbia will file with the SEC a Registration Statement on Form S-4 that will include 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 when they become available and any other relevant documents filed with the SEC, as well as any amendments or supplements to those documents, because they will contain important information. A definitive Joint Proxy Statement/Prospectus will be sent to the shareholders of each institution seeking any required shareholder approvals. The Joint Proxy Statement/Prospectus and other relevant materials (when they become available) filed with the SEC may be obtained free of charge at the SEC’s Website at http://www.sec.gov. Columbia and Pacific Continental shareholders are urged to read the Joint Proxy Statement/Prospectus and the other relevant materials before voting on 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 Us” and then under the heading “Investor Relations.” Copies can also be obtained, free of charge, by directing a written request to Columbia Banking System, Inc., Attention: Corporate Secretary, 1301 A Street, Suite 800, Tacoma, Washington 98401-2156 or to Pacific Continental Corporation, Attention: Corporate Secretary, 111 West Seventh Avenue, P.O. Box 10727, Eugene, Oregon 97440-2727.

Pacific Continental and Columbia and their respective directors and executive officers and certain other persons may be deemed to be participants in the solicitation of proxies from the shareholders of Columbia and Pacific Continental in connection with the merger. Information about the directors and executive officers of Columbia and their ownership of Columbia common stock is set forth in the proxy statement for Columbia’s 2016 annual meeting of shareholders, as filed with the SEC on a Schedule 14A on March 16, 2016. Information about the directors and executive officers of Pacific Continental and their ownership of Pacific Continental common stock is set forth in the proxy statement for Pacific Continental’s 2016 annual meeting of shareholders, as filed with the SEC on a Schedule 14A on March 15, 2016. Additional information regarding the interests of those participants and other persons who may be deemed participants in the transaction may be obtained by reading the Joint Proxy Statement/Prospectus regarding the merger when it becomes available. Free copies of this document may be obtained as described in the preceding paragraph.

PACIFIC CONTINENTAL CORPORATION and subsidiary

Consolidated Income Statements

(Dollars in thousands, except share and per share amounts)

(Unaudited)

NA Not applicable

PACIFIC CONTINENTAL CORPORATION and subsidiary

Year Ended Consolidated Income Statements

(Dollars in thousands, except share and per share amounts)

(Unaudited)

PACIFIC CONTINENTAL CORPORATION and subsidiary

Consolidated Balance Sheets

(Dollars in thousands, except share and per share amounts)

(Unaudited)

NA Not applicable

PACIFIC CONTINENTAL CORPORATION and subsidiary

Loans by Type

(Dollars in thousands)

(Unaudited)

PACIFIC CONTINENTAL CORPORATION and subsidiary

Selected Other Financial Information and Ratios

(Dollars in thousands)

(Unaudited)