0001193125-07-075343 8-K 4 20070329 7.01 8.01 9.01 20070405 20070405 COLUMBIA BANKING SYSTEM INC 0000887343 6022 911422237 WA 1231 8-K 34 000-20288 07751557 1102 BROADWAY PLAZA TACOMA WA 98402 2533051900 1102 BROADWAY PLAZA TACOMA WA 98402 8-K 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