0001193125-07-075344 425 4 20070405 20070405 COLUMBIA BANKING SYSTEM INC 0000887343 6022 911422237 WA 1231 425 34 000-20288 07751547 1102 BROADWAY PLAZA TACOMA WA 98402 2533051900 1102 BROADWAY PLAZA TACOMA WA 98402 COLUMBIA BANKING SYSTEM INC 0000887343 6022 911422237 WA 1231 425 1102 BROADWAY PLAZA TACOMA WA 98402 2533051900 1102 BROADWAY PLAZA TACOMA WA 98402 425 1 d8k.htm FORM 8-K EX-2.1 2 dex21.htm PLAN AND AGREEMENT OF MERGER EX-99.1 3 dex991.htm SCRIPT TO CONFERENCE CALL EX-99.2 4 dex992.htm QUESTION AND ANSWER SECTION OF CONFERENCE CALL