<TABLE> <S> <C>
<PAGE>
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM SOUTHWEST
BANCORP'S QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTER ENDED SEPTEMBER 30,
2000, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 29,924
<INT-BEARING-DEPOSITS> 1,363
<FED-FUNDS-SOLD> 0
<TRADING-ASSETS> 0
<INVESTMENTS-HELD-FOR-SALE> 158,337
<INVESTMENTS-CARRYING> 66,703
<INVESTMENTS-MARKET> 66,288
<LOANS> 914,666
<ALLOWANCE> 11,845
<TOTAL-ASSETS> 1,204,017
<DEPOSITS> 934,159
<SHORT-TERM> 164,257
<LIABILITIES-OTHER> 11,280
<LONG-TERM> 25,013
0
0
<COMMON> 4,081
<OTHER-SE> 65,227
<TOTAL-LIABILITIES-AND-EQUITY> 1,204,017
<INTEREST-LOAN> 61,059
<INTEREST-INVEST> 10,101
<INTEREST-OTHER> 115
<INTEREST-TOTAL> 71,275
<INTEREST-DEPOSIT> 32,766
<INTEREST-EXPENSE> 41,661
<INTEREST-INCOME-NET> 29,614
<LOAN-LOSSES> 2,725
<SECURITIES-GAINS> 0
<EXPENSE-OTHER> 21,963
<INCOME-PRETAX> 11,264
<INCOME-PRE-EXTRAORDINARY> 11,264
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 7,435
<EPS-BASIC> 1.94
<EPS-DILUTED> 1.92
<YIELD-ACTUAL> 8.52
<LOANS-NON> 11,821
<LOANS-PAST> 249
<LOANS-TROUBLED> 0
<LOANS-PROBLEM> 36,980
<ALLOWANCE-OPEN> 11,190
<CHARGE-OFFS> 2,572
<RECOVERIES> 502
<ALLOWANCE-CLOSE> 11,845
<ALLOWANCE-DOMESTIC> 11,845
<ALLOWANCE-FOREIGN> 0
<ALLOWANCE-UNALLOCATED> 4,397
</TABLE>