<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,
1999 FOR TRENWICK GROUP INC.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLARS

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               JUN-30-1999
<EXCHANGE-RATE>                                      1
<DEBT-HELD-FOR-SALE>                           876,747
<DEBT-CARRYING-VALUE>                                0
<DEBT-MARKET-VALUE>                                  0
<EQUITIES>                                      60,967
<MORTGAGE>                                           0
<REAL-ESTATE>                                        0
<TOTAL-INVEST>                                 937,714
<CASH>                                          19,463
<RECOVER-REINSURE>                             152,777<F1>
<DEFERRED-ACQUISITION>                          44,179
<TOTAL-ASSETS>                               1,385,057
<POLICY-LOSSES>                                666,101
<UNEARNED-PREMIUMS>                            181,658
<POLICY-OTHER>                                       0
<POLICY-HOLDER-FUNDS>                                0
<NOTES-PAYABLE>                                 75,000
<PREFERRED-MANDATORY>                          110,000
<PREFERRED>                                          0
<COMMON>                                         1,063
<OTHER-SE>                                     321,525
<TOTAL-LIABILITY-AND-EQUITY>                 1,385,057
<PREMIUMS>                                     125,039
<INVESTMENT-INCOME>                             27,140
<INVESTMENT-GAINS>                               3,029
<OTHER-INCOME>                                     113
<BENEFITS>                                      81,324
<UNDERWRITING-AMORTIZATION>                     34,453
<UNDERWRITING-OTHER>                            22,788
<INCOME-PRETAX>                                 16,756
<INCOME-TAX>                                     2,986
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    13,770
<EPS-BASIC>                                     1.30<F2>
<EPS-DILUTED>                                     1.28
<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>