<ARTICLE> 7
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS CONTAINED IN FORM 10-Q FOR THE SIX MONTHS ENDED JUNE 30,
1998 FOR TRENWICK GROUP INC.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLARS
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<EXCHANGE-RATE>                                      1
<DEBT-HELD-FOR-SALE>                           903,385
<DEBT-CARRYING-VALUE>                                0
<DEBT-MARKET-VALUE>                                  0
<EQUITIES>                                      57,133
<MORTGAGE>                                           0
<REAL-ESTATE>                                        0
<TOTAL-INVEST>                                 960,518
<CASH>                                          60,881
<RECOVER-REINSURE>                             147,680<F1>
<DEFERRED-ACQUISITION>                          33,589
<TOTAL-ASSETS>                               1,390,338
<POLICY-LOSSES>                                660,009
<UNEARNED-PREMIUMS>                            150,918
<POLICY-OTHER>                                       0
<POLICY-HOLDER-FUNDS>                                0
<NOTES-PAYABLE>                                 75,000
<PREFERRED-MANDATORY>                          110,000
<PREFERRED>                                          0
<COMMON>                                         1,206
<OTHER-SE>                                     371,568
<TOTAL-LIABILITY-AND-EQUITY>                 1,390,338
<PREMIUMS>                                     116,788
<INVESTMENT-INCOME>                             27,360
<INVESTMENT-GAINS>                               1,260
<OTHER-INCOME>                                     332
<BENEFITS>                                      69,576
<UNDERWRITING-AMORTIZATION>                     35,931
<UNDERWRITING-OTHER>                            10,568
<INCOME-PRETAX>                                 21,616
<INCOME-TAX>                                     3,396
<INCOME-CONTINUING>                             18,220
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    18,220
<EPS-PRIMARY>                                     1.53<F2>
<EPS-DILUTED>                                     1.51
<RESERVE-OPEN>                                       0
<PROVISION-CURRENT>                                  0
<PROVISION-PRIOR>                                    0
<PAYMENTS-CURRENT>                                   0
<PAYMENTS-PRIOR>                                     0
<RESERVE-CLOSE>                                      0
<CUMULATIVE-DEFICIENCY>                              0
<FN>
<F1>REPRESENTS NET REINSURANCE RECOVERABLE BALANCES AFTER OFFSET OF FUNDS HELD AND
REINSURANCE BALANCES PAYABLE.
<F2>REPRESENTS BASIC EARNINGS PER SHARE.
</FN>