<TABLE> <S> <C>

<PAGE>
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS FINANCIAL INFORMATION EXTRACTED FROM THE CONSOLIDATED
FINANCIAL STATEMENTS OF INTERWEST BANCORP, INC. AND FOR THE SIX MONTHS ENDED
JUNE 30, 2000, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-START>                             JAN-01-2000
<PERIOD-END>                               JUN-30-2000
<CASH>                                          76,936
<INT-BEARING-DEPOSITS>                          30,111
<FED-FUNDS-SOLD>                                15,500
<TRADING-ASSETS>                                     0
<INVESTMENTS-HELD-FOR-SALE>                    690,312
<INVESTMENTS-CARRYING>                          67,106
<INVESTMENTS-MARKET>                            64,695
<LOANS>                                      1,741,703
<ALLOWANCE>                                     15,538
<TOTAL-ASSETS>                               2,793,359
<DEPOSITS>                                   1,583,948
<SHORT-TERM>                                   594,328
<LIABILITIES-OTHER>                             28,755
<LONG-TERM>                                    425,812
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        25,802
<OTHER-SE>                                     134,714
<TOTAL-LIABILITIES-AND-EQUITY>               2,793,359
<INTEREST-LOAN>                                 78,603
<INTEREST-INVEST>                               27,998
<INTEREST-OTHER>                                   880
<INTEREST-TOTAL>                               107,481
<INTEREST-DEPOSIT>                              28,895
<INTEREST-EXPENSE>                              61,242
<INTEREST-INCOME-NET>                           46,239
<LOAN-LOSSES>                                    1,950
<SECURITIES-GAINS>                             (6,775)
<EXPENSE-OTHER>                                 45,966
<INCOME-PRETAX>                                    337
<INCOME-PRE-EXTRAORDINARY>                       (252)
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     (252)
<EPS-BASIC>                                     (0.02)
<EPS-DILUTED>                                   (0.02)
<YIELD-ACTUAL>                                    3.54
<LOANS-NON>                                     11,429
<LOANS-PAST>                                         0
<LOANS-TROUBLED>                                     0
<LOANS-PROBLEM>                                      0
<ALLOWANCE-OPEN>                                15,182
<CHARGE-OFFS>                                    1,773
<RECOVERIES>                                       179
<ALLOWANCE-CLOSE>                               15,538
<ALLOWANCE-DOMESTIC>                            11,634
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                          3,904


</TABLE>