<TABLE> <S> <C>
<PAGE>
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM NATIONAL
MERCANTILE BANCORP'S SEPTEMBER 30, 2000 CONSOLIDATED FINANCIAL STATEMENTS AND
RELATED SCHEDULES.
</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> 9,711
<INT-BEARING-DEPOSITS> 0
<FED-FUNDS-SOLD> 12,550
<TRADING-ASSETS> 0
<INVESTMENTS-HELD-FOR-SALE> 68,599
<INVESTMENTS-CARRYING> 0
<INVESTMENTS-MARKET> 0
<LOANS> 101,188
<ALLOWANCE> 2,585
<TOTAL-ASSETS> 191,805
<DEPOSITS> 137,077
<SHORT-TERM> 31,500
<LIABILITIES-OTHER> 1,904
<LONG-TERM> 2,500
0
6,292
<COMMON> 29,876
<OTHER-SE> (17,344)
<TOTAL-LIABILITIES-AND-EQUITY> 191,805
<INTEREST-LOAN> 6,317
<INTEREST-INVEST> 3,628
<INTEREST-OTHER> 399
<INTEREST-TOTAL> 10,344
<INTEREST-DEPOSIT> 1,990
<INTEREST-EXPENSE> 3,572
<INTEREST-INCOME-NET> 6,772
<LOAN-LOSSES> (576)
<SECURITIES-GAINS> 18
<EXPENSE-OTHER> 5,819
<INCOME-PRETAX> 2,214
<INCOME-PRE-EXTRAORDINARY> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 2,169
<EPS-BASIC> 2.41
<EPS-DILUTED> 0.85
<YIELD-ACTUAL> 5.42
<LOANS-NON> 683
<LOANS-PAST> 0
<LOANS-TROUBLED> 0
<LOANS-PROBLEM> 52
<ALLOWANCE-OPEN> 1,896
<CHARGE-OFFS> 114
<RECOVERIES> 1,379
<ALLOWANCE-CLOSE> 2,585
<ALLOWANCE-DOMESTIC> 1,544
<ALLOWANCE-FOREIGN> 0
<ALLOWANCE-UNALLOCATED> 1,041
</TABLE>