<TABLE> <S> <C>

<PAGE>

<ARTICLE> 7
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM JOHN HANCOCK
MUTUAL LIFE INSURANCE COMPANY AND SUBSIDIARIES AND IS QUALIFIED IN ITS ENTIRETY
BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000,000

<S>                             <C>                      <C>
<PERIOD-TYPE>                   YEAR                     YEAR
<FISCAL-YEAR-END>                          SEP-30-1999              DEC-31-1998
<PERIOD-START>                             JAN-01-1999              JAN-01-1998
<PERIOD-END>                               SEP-30-1999              DEC-31-1998
<DEBT-HELD-FOR-SALE>                            17,087                   15,222
<DEBT-CARRYING-VALUE>                           13,524                   12,978
<DEBT-MARKET-VALUE>                             14,067                   13,922
<EQUITIES>                                       1,114                    1,064
<MORTGAGE>                                      10,234                    9,616
<REAL-ESTATE>                                      573                    1,483
<TOTAL-INVEST>                                  46,466                   43,778
<CASH>                                           1,066                    1,876
<RECOVER-REINSURE>                               1,369                    1,634
<DEFERRED-ACQUISITION>                           3,000                    2,759
<TOTAL-ASSETS>                                  80,206                   76,967
<POLICY-LOSSES>                                 28,202                   27,071
<UNEARNED-PREMIUMS>                                385                      374
<POLICY-OTHER>                                     459                      886
<POLICY-HOLDER-FUNDS>                           16,195                   14,672
<NOTES-PAYABLE>                                    891                    1,031
<PREFERRED-MANDATORY>                                0                        0
<PREFERRED>                                          0                        0
<COMMON>                                             0                        0
<OTHER-SE>                                       5,135                    4,955
<TOTAL-LIABILITY-AND-EQUITY>                    80,206                   76,967
<PREMIUMS>                                       2,033                    2,198
<INVESTMENT-INCOME>                              2,581                    3,331
<INVESTMENT-GAINS>                                 178                      106
<OTHER-INCOME>                                   1,026                    1,267
<BENEFITS>                                       3,600                    4,152
<UNDERWRITING-AMORTIZATION>                        145                      250
<UNDERWRITING-OTHER>                               997                    1,383
<INCOME-PRETAX>                                    715                      644
<INCOME-TAX>                                       239                      184
<INCOME-CONTINUING>                                475                      460
<DISCONTINUED>                                       0                        0
<EXTRAORDINARY>                                     57                       12
<CHANGES>                                           10                        0
<NET-INCOME>                                       409                      448
<EPS-BASIC>                                          0                        0
<EPS-DILUTED>                                        0                        0
<RESERVE-OPEN>                                       0                        0
<PROVISION-CURRENT>                                  0                        0
<PROVISION-PRIOR>                                    0                        0
<PAYMENTS-CURRENT>                                   0                        0
<PAYMENTS-PRIOR>                                     0                        0
<RESERVE-CLOSE>                                      0                        0
<CUMULATIVE-DEFICIENCY>                              0                        0


</TABLE>