<SEC-DOCUMENT>0000887343-17-000176-index.html : 20171218
<SEC-HEADER>0000887343-17-000176.hdr.sgml : 20171218
<ACCEPTANCE-DATETIME>20171218164025
ACCESSION NUMBER:		0000887343-17-000176
CONFORMED SUBMISSION TYPE:	8-K/A
PUBLIC DOCUMENT COUNT:		5
CONFORMED PERIOD OF REPORT:	20171218
ITEM INFORMATION:		Completion of Acquisition or Disposition of Assets
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20171218
DATE AS OF CHANGE:		20171218

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COLUMBIA BANKING SYSTEM INC
		CENTRAL INDEX KEY:			0000887343
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				911422237
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-20288
		FILM NUMBER:		171261878

	BUSINESS ADDRESS:	
		STREET 1:		1301 A STREET
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98402
		BUSINESS PHONE:		2533051900

	MAIL ADDRESS:	
		STREET 1:		1301 A STREET
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98402
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K/A
<SEQUENCE>1
<FILENAME>form8-kamergerclosingannou.htm
<DESCRIPTION>8-K/A
<TEXT>
Document 1 - file: form8-kamergerclosingannou.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>2
<FILENAME>exhibit231consentofindepen.htm
<DESCRIPTION>CONSENT
<TEXT>
Document 2 - file: exhibit231consentofindepen.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>3
<FILENAME>exhibit991pcbkannual2016fi.htm
<DESCRIPTION>PACIFIC CONTINENTAL HISTORICAL FINANCIAL STATEMENTS ANNUAL 2016
<TEXT>
Document 3 - file: exhibit991pcbkannual2016fi.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.2
<SEQUENCE>4
<FILENAME>exhibit992pcbkinterimsepte.htm
<DESCRIPTION>PACIFIC CONTINENTAL HISTORICAL FINANCIAL STATEMENTS SEP 2017
<TEXT>
Document 4 - file: exhibit992pcbkinterimsepte.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.3
<SEQUENCE>5
<FILENAME>exhibit993proformafinancia.htm
<DESCRIPTION>PRO FORMA FINANCIAL INFORMATION
<TEXT>
Document 5 - file: exhibit993proformafinancia.htm

</DOCUMENT>
</SEC-DOCUMENT>