WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000872649
<NAME> LOOMIS SAYLES & COMPANY, L.P.
<SERIES>
<NUMBER> 180
<NAME> LOOMIS SAYLES MANAGED BOND FUND, INSTITUTIONAL
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> SEP-30-2000
<PERIOD-START> OCT-01-1999
<PERIOD-END> MAR-31-2000
<INVESTMENTS-AT-COST> 39514996
<INVESTMENTS-AT-VALUE> 38450294
<RECEIVABLES> 514979
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 79670
<TOTAL-ASSETS> 39044943
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 1172583
<TOTAL-LIABILITIES> 1172583
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 38658559
<SHARES-COMMON-STOCK> 3886050
<SHARES-COMMON-PRIOR> 3498200
<ACCUMULATED-NII-CURRENT> 228818
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 49685
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (1064702)
<NET-ASSETS> 37872360
<DIVIDEND-INCOME> 26616
<INTEREST-INCOME> 1595514
<OTHER-INCOME> 0
<EXPENSES-NET> (296764)
<NET-INVESTMENT-INCOME> 1325366
<REALIZED-GAINS-CURRENT> 175084
<APPREC-INCREASE-CURRENT> 362061
<NET-CHANGE-FROM-OPS> 1862511
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (1316308)
<DISTRIBUTIONS-OF-GAINS> (567630)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 2326500
<NUMBER-OF-SHARES-REDEEMED> (1938650)
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 3608791
<ACCUMULATED-NII-PRIOR> 219760
<ACCUMULATED-GAINS-PRIOR> 442231
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 118706
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 505421
<AVERAGE-NET-ASSETS> 39568558
<PER-SHARE-NAV-BEGIN> 9.79
<PER-SHARE-NII> 0.32
<PER-SHARE-GAIN-APPREC> 0.12
<PER-SHARE-DIVIDEND> (0.33)
<PER-SHARE-DISTRIBUTIONS> (0.15)
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 9.75
<EXPENSE-RATIO> 1.50
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0
</TABLE>
