<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 SEPTEMBER 30,
1999, AND THE RELATED STATEMENTS OF INCOME, CHANGES IN SHAREHOLDERS' EQUITY AND
CASH FLOWS FOR THE PERIOD ENDING SEPTEMBER 30, 1999 AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>

<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          JAN-01-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               SEP-30-1999
<CASH>                                          21,982
<INT-BEARING-DEPOSITS>                               0
<FED-FUNDS-SOLD>                                14,135
<TRADING-ASSETS>                                     0
<INVESTMENTS-HELD-FOR-SALE>                    126,461
<INVESTMENTS-CARRYING>                         155,790
<INVESTMENTS-MARKET>                           155,417
<LOANS>                                        344,952
<ALLOWANCE>                                      5,044
<TOTAL-ASSETS>                                 552,316
<DEPOSITS>                                     472,606
<SHORT-TERM>                                    28,310
<LIABILITIES-OTHER>                              3,437
<LONG-TERM>                                          0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         8,028
<OTHER-SE>                                      39,935
<TOTAL-LIABILITIES-AND-EQUITY>                 552,316
<INTEREST-LOAN>                                 22,387
<INTEREST-INVEST>                                6,340
<INTEREST-OTHER>                                   610
<INTEREST-TOTAL>                                29,337
<INTEREST-DEPOSIT>                               9,307
<INTEREST-EXPENSE>                               9,863
<INTEREST-INCOME-NET>                           19,474
<LOAN-LOSSES>                                      778
<SECURITIES-GAINS>                                   0
<EXPENSE-OTHER>                                 11,298
<INCOME-PRETAX>                                 10,225
<INCOME-PRE-EXTRAORDINARY>                       6,690
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     6,690
<EPS-BASIC>                                       1.04
<EPS-DILUTED>                                     1.00
<YIELD-ACTUAL>                                    5.33
<LOANS-NON>                                      2,899
<LOANS-PAST>                                         0
<LOANS-TROUBLED>                                     0
<LOANS-PROBLEM>                                  9,196
<ALLOWANCE-OPEN>                                 4,724
<CHARGE-OFFS>                                      594
<RECOVERIES>                                       136
<ALLOWANCE-CLOSE>                                5,044
<ALLOWANCE-DOMESTIC>                             5,044
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                              0


</TABLE>