<TABLE> <S> <C>

<PAGE>
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED BALANCE SHEETS OF SUMMIT BANCSHARES, INC., AS OF JUNE 30, 1997, AND
THE RELATED STATEMENTS OF INCOME, CHANGES IN SHAREHOLDERS' EQUITY AND CASH FLOWS
FOR THE PERIOD ENDING JUNE 30, 1997 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-31-1996
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               JUN-30-1997
<CASH>                                          28,170
<INT-BEARING-DEPOSITS>                               0
<FED-FUNDS-SOLD>                                10,900
<TRADING-ASSETS>                                     0
<INVESTMENTS-HELD-FOR-SALE>                     61,276
<INVESTMENTS-CARRYING>                         113,655
<INVESTMENTS-MARKET>                           113,738
<LOANS>                                        246,816
<ALLOWANCE>                                      3,512
<TOTAL-ASSETS>                                 409,931
<DEPOSITS>                                     360,949
<SHORT-TERM>                                         0
<LIABILITIES-OTHER>                             11,109
<LONG-TERM>                                          0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         4,045
<OTHER-SE>                                      33,828
<TOTAL-LIABILITIES-AND-EQUITY>                 409,931
<INTEREST-LOAN>                                 11,330
<INTEREST-INVEST>                                3,547
<INTEREST-OTHER>                                   319
<INTEREST-TOTAL>                                15,196
<INTEREST-DEPOSIT>                               4,996
<INTEREST-EXPENSE>                               5,253
<INTEREST-INCOME-NET>                            9,943
<LOAN-LOSSES>                                      352
<SECURITIES-GAINS>                                   0
<EXPENSE-OTHER>                                  5,922
<INCOME-PRETAX>                                  5,251
<INCOME-PRE-EXTRAORDINARY>                       3,444
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     3,444
<EPS-PRIMARY>                                     1.06
<EPS-DILUTED>                                     1.06
<YIELD-ACTUAL>                                    5.60
<LOANS-NON>                                        901
<LOANS-PAST>                                         0
<LOANS-TROUBLED>                                     0
<LOANS-PROBLEM>                                  8,318
<ALLOWANCE-OPEN>                                 2,972
<CHARGE-OFFS>                                       71
<RECOVERIES>                                       259
<ALLOWANCE-CLOSE>                                3,512
<ALLOWANCE-DOMESTIC>                             3,512
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                              0
        

</TABLE>