10-K/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

(Amendment No. 1)

FORM 10-K/A

ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2013 or

o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number 0-20288

COLUMBIA BANKING SYSTEM, INC.

(Exact name of registrant as specified in its charter)

Washington	91-1422237
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification Number)

1301 “A” Street

Tacoma, Washington 98402

(Address of principal executive offices) (Zip code)

Registrant’s Telephone Number, Including Area Code: (253) 305-1900

Securities Registered Pursuant to Section 12(b) of the Act:

Common Stock, No Par Value

(Title of class)

Securities Registered Pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ý    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  ý

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ý    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ý    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (17 C.F.R. 229.405) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer, or a smaller reporting company. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act (check one):

ý  Large Accelerated Filer        ¨  Accelerated Filer        ¨  Non-accelerated Filer        ¨  Smaller Reporting Company

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  ý

The aggregate market value of Common Stock held by non-affiliates of the registrant at June 30, 2013 was $1,204,816,739 based on the closing sale price of the Common Stock on that date.

The number of shares of registrant’s Common Stock outstanding at January 31, 2014 was 51,282,776.

DOCUMENTS INCORPORATED BY REFERENCE: None

EXPLANATORY NOTE

This Amendment on Form 10-K/A (“Amendment No. 1”) amends the registrant’s Form 10-K for the year ended December 31, 2013, as filed with the Securities and Exchange Commission on March 3, 2014 (the “Form 10-K”), solely for the purpose of correcting errors in Exhibit 23 - Consent of Independent Registered Public Accounting Firm. Accordingly, we are filing this Amendment No. 1 to the Form 10-K to include a corrected Consent of Independent Registered Public Accounting Firm, which is filed as Exhibit 23.

As required by Rule 12b-15 under the Securities Exchange Act of 1934, new certifications of our principal executive officer and principal financial officer are being filed as exhibits to this Amendment No. 1. No other information included in the Form 10-K has been amended. Except for the matter described above, this amendment does not change any previously reported financial results, modify or update disclosures in the Form 10-K, or reflect events occurring after the date of the filing of the Form 10-K.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 1 to the report to be signed on its behalf by the undersigned, thereunto duly authorized, on March 26, 2014.

COLUMBIA BANKING SYSTEM, INC.
(Registrant)
By:	/s/ CLINT E. STEIN
	Clint E. Stein
	Executive Vice President and Chief Financial Officer
	(Principal Financial and Accounting Officer)

INDEX TO EXHIBITS

Exhibit No.	Exhibit
23+	Consent of Deloitte & Touche LLP
31.1+	Certification of Chief Executive Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
31.2+	Certification of Chief Financial Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
32+	Certification Filed Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

+ Filed herewith

EX-23

EXHIBIT 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-184742 on Form S-4 and Nos. 333-187690, 333-160371, 333-160370, 333-145207, 333-144811, 333-135439, 333-125298, 333-120131, 333-100420 and 33-95766 on Form S-8 of our reports dated February 28, 2014, relating to the consolidated financial statements of Columbia Banking System, Inc., and the effectiveness of Columbia Banking System, Inc.'s internal control over financial reporting, appearing in the Annual Report on Form 10-K of Columbia Banking System, Inc., for the year ended December 31, 2013.

/s/ Deloitte & Touche LLP

Seattle, Washington

March 26, 2014

EX-31.1

EXHIBIT 31.1

CERTIFICATION

I, Melanie J. Dressel, certify that:

1. I have reviewed this Amendment No. 1 to the annual report on Form 10-K of Columbia Banking System, Inc. (“amended report”);

2. Based on my knowledge, this amended report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this amended report;

3. Based on my knowledge, the financial statements, and other financial information included in this amended report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this amended report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this amended report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this amended report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this amended report based on such evaluation; and

(d) Disclosed in this amended report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

/s/ MELANIE J. DRESSEL

Melanie J. Dressel
President and Chief Executive Officer

Date: March 26, 2014

EX-31.2

EXHIBIT 31.2

CERTIFICATION

I, Clint E. Stein, certify that:

1. I have reviewed this Amendment No. 1 to the annual report on Form 10-K of Columbia Banking System, Inc. (“amended report”);

2. Based on my knowledge, this amended report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this amended report;

3. Based on my knowledge, the financial statements, and other financial information included in this amended report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this amended report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this amended report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this amended report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this amended report based on such evaluation; and

(d) Disclosed in this amended report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

/s/ CLINT E. STEIN

Clint E. Stein
Executive Vice President and
Chief Financial Officer

Date: March 26, 2014

EX-32

EXHIBIT 32

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Amendment No. 1 to the Annual Report of Columbia Banking System, Inc. (the “Company”) on Form 10-K for the period ended December 31, 2013 as filed with the Securities and Exchange Commission on the date hereof (the “Amended Report”), we, Melanie J. Dressel, President and Chief Executive Officer, and Clint E. Stein, Executive Vice President and Chief Financial Officer, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Amended Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Amended Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ MELANIE J. DRESSEL

Melanie J. Dressel

President and Chief Executive Officer

Columbia Banking System, Inc.

/s/ CLINT E. STEIN

Clint E. Stein

Executive Vice President and

Chief Financial Officer

Columbia Banking System, Inc.

Dated: March 26, 2014