<TABLE> <S> <C>

<PAGE>
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE MAHONING
NATIONAL BANCORP, INC., CONSOLIDATED STATEMENT OF CONDITION AT SEPTEMBER 30,
1998 AND THE CONSOLIDATED STATEMENT OF INCOME FOR THE NINE MONTHS ENDED
SEPTEMBER 30, 1998 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-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               SEP-30-1998
<CASH>                                          21,867
<INT-BEARING-DEPOSITS>                               0
<FED-FUNDS-SOLD>                                     0
<TRADING-ASSETS>                                     0
<INVESTMENTS-HELD-FOR-SALE>                    231,689
<INVESTMENTS-CARRYING>                          29,486
<INVESTMENTS-MARKET>                            29,676
<LOANS>                                        487,336
<ALLOWANCE>                                      7,535
<TOTAL-ASSETS>                                 785,911
<DEPOSITS>                                     537,723
<SHORT-TERM>                                   134,841
<LIABILITIES-OTHER>                              5,164
<LONG-TERM>                                     12,435
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         6,300
<OTHER-SE>                                      89,448
<TOTAL-LIABILITIES-AND-EQUITY>                 785,911
<INTEREST-LOAN>                                 32,572
<INTEREST-INVEST>                               10,914
<INTEREST-OTHER>                                   442
<INTEREST-TOTAL>                                43,928
<INTEREST-DEPOSIT>                              11,905
<INTEREST-EXPENSE>                              17,298
<INTEREST-INCOME-NET>                           26,630
<LOAN-LOSSES>                                    2,178
<SECURITIES-GAINS>                                   0
<EXPENSE-OTHER>                                 15,630
<INCOME-PRETAX>                                 15,434
<INCOME-PRE-EXTRAORDINARY>                      10,391
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    10,391
<EPS-PRIMARY>                                     1.65
<EPS-DILUTED>                                     1.65
<YIELD-ACTUAL>                                    7.93
<LOANS-NON>                                      1,019
<LOANS-PAST>                                       605
<LOANS-TROUBLED>                                    54
<LOANS-PROBLEM>                                      0
<ALLOWANCE-OPEN>                                 7,524
<CHARGE-OFFS>                                    2,800
<RECOVERIES>                                       633
<ALLOWANCE-CLOSE>                                7,535
<ALLOWANCE-DOMESTIC>                             7,535
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                          1,028
        

</TABLE>