<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 7
<MULTIPLIER> 1,000
       
<S>                             <C>                   <C> 
<PERIOD-TYPE>                   3-MOS                 9-MOS
<FISCAL-YEAR-END>                       SEP-30-1998           SEP-30-1998
<PERIOD-START>                          APR-01-1998           OCT-01-1998
<PERIOD-END>                            JUN-30-1998           JUN-30-1998
<DEBT-HELD-FOR-SALE>                              0                     0
<DEBT-CARRYING-VALUE>                             0                     0
<DEBT-MARKET-VALUE>                               0                     0
<EQUITIES>                                        0                     0
<MORTGAGE>                                        0                     0
<REAL-ESTATE>                                     0                     0
<TOTAL-INVEST>                              493,373               493,373
<CASH>                                       85,146                85,146
<RECOVER-REINSURE>                                0                     0
<DEFERRED-ACQUISITION>                       14,742                14,742
<TOTAL-ASSETS>                              752,926               752,926
<POLICY-LOSSES>                              65,550                65,550
<UNEARNED-PREMIUMS>                          93,788                93,788
<POLICY-OTHER>                                    0                     0
<POLICY-HOLDER-FUNDS>                             0                     0
<NOTES-PAYABLE>                                   0                     0
<COMMON>                                     15,176                15,176
<PREFERRED-MANDATORY>                             0                     0
<PREFERRED>                                   3,000                 3,000
<OTHER-SE>                                  426,476               426,476
<TOTAL-LIABILITY-AND-EQUITY>                752,926<F1>           752,926<F1>
<PREMIUMS>                                   42,053               121,878
<INVESTMENT-INCOME>                           8,732                25,767
<INVESTMENT-GAINS>                              515                 2,532
<OTHER-INCOME>                                    0                    63
<BENEFITS>                                   23,607                52,243
<UNDERWRITING-AMORTIZATION>                   6,815                19,189
<UNDERWRITING-OTHER>                          2,705                 8,933
<INCOME-PRETAX>                              18,173                69,875
<INCOME-TAX>                                      0                     0
<INCOME-CONTINUING>                          18,173                69,875
<DISCONTINUED>                                    0                     0
<EXTRAORDINARY>                                   0                     0
<CHANGES>                                         0                     0
<NET-INCOME>                                 18,173                69,875
<EPS-PRIMARY>                                  0.86<F2>              3.39<F2>
<EPS-DILUTED>                                  0.78<F3>              3.09<F3>
<RESERVE-OPEN>                                    0<F4>                 0<F4>
<PROVISION-CURRENT>                               0<F4>                 0<F4>
<PROVISION-PRIOR>                                 0<F4>                 0<F4>
<PAYMENTS-CURRENT>                                0<F4>                 0<F4>
<PAYMENTS-PRIOR>                                  0<F4>                 0<F4>
<RESERVE-CLOSE>                                   0<F4>                 0<F4>
<CUMULATIVE-DEFICIENCY>                           0<F4>                 0<F4>
<FN>

<F1> Includes minority interest.

<F2> Basic EPS, following adoption of SFAS 128.

<F3> Diluted EPS, following adoption of SFAS 128.

<F4> Amounts for Securities Act Industry Guide 6 and Exchange Act Industry Guide
     4 disclosures are not provided because the Company's loss reserves do not 
     exceed one-half of the consolidated common shareholders' equity.
</FN>
        

</TABLE>