WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.

 

<ARTICLE> 6
<LEGEND>
Putnam Money Market Fund


   <NUMBER> 4
   <NAME>  Class B

                             
<PERIOD-TYPE>                   ANNUAL
<FISCAL-YEAR-END>                          SEP-30-2000
<PERIOD-END>                               SEP-30-2000
<INVESTMENTS-AT-COST>                    4,470,091,583
<INVESTMENTS-AT-VALUE>                   4,470,091,583
<RECEIVABLES>                              179,641,583
<ASSETS-OTHER>                                 292,874
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                           4,650,026,040
<PAYABLE-FOR-SECURITIES>                             0
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                   52,560,522
<TOTAL-LIABILITIES>                         52,560,522
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                 4,597,465,518
<SHARES-COMMON-STOCK>                      649,826,226
<SHARES-COMMON-PRIOR>                    1,041,452,406
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                              0
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                             0
<NET-ASSETS>                             4,597,465,518
<DIVIDEND-INCOME>                                    0
<INTEREST-INCOME>                          280,714,304
<OTHER-INCOME>                                       0
<EXPENSES-NET>                              25,222,715
<NET-INVESTMENT-INCOME>                    255,491,589
<REALIZED-GAINS-CURRENT>                             0
<APPREC-INCREASE-CURRENT>                            0
<NET-CHANGE-FROM-OPS>                      255,491,589
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                 (41,749,961)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                  2,539,282,766
<NUMBER-OF-SHARES-REDEEMED>            (2,968,511,949)
<SHARES-REINVESTED>                         37,603,003
<NET-CHANGE-IN-ASSETS>                   (288,687,405)
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                       14,348,517
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                             26,586,464
<AVERAGE-NET-ASSETS>                       808,595,139
<PER-SHARE-NAV-BEGIN>                             1.00
<PER-SHARE-NII>                                    .05
<PER-SHARE-GAIN-APPREC>                              0
<PER-SHARE-DIVIDEND>                             (.05)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               1.00
<EXPENSE-RATIO>                                    .99
[AVG-DEBT-OUTSTANDING]                               0
[AVG-DEBT-PER-SHARE]                                 0