WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000917469
<NAME> LOOMIS SAYLES & COMPANY, L.P.
<SERIES>
<NUMBER> 06
<NAME> LSIT CORE FIXED INCOME FUND
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> SEP-30-2000
<PERIOD-START> OCT-01-2000
<PERIOD-END> SEP-30-2000
<INVESTMENTS-AT-COST> 16109526
<INVESTMENTS-AT-VALUE> 15883456
<RECEIVABLES> 254113
<ASSETS-OTHER> 1315
<OTHER-ITEMS-ASSETS> 6160
<TOTAL-ASSETS> 16145044
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 37934
<TOTAL-LIABILITIES> 37934
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 16397546
<SHARES-COMMON-STOCK> 1532255
<SHARES-COMMON-PRIOR> 2140260
<ACCUMULATED-NII-CURRENT> 1007494
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> (1071860)
<ACCUM-APPREC-OR-DEPREC> (226070)
<NET-ASSETS> 16107110
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 1479857
<OTHER-INCOME> 0
<EXPENSES-NET> (107596)
<NET-INVESTMENT-INCOME> 1372261
<REALIZED-GAINS-CURRENT> (1005793)
<APPREC-INCREASE-CURRENT> 633029
<NET-CHANGE-FROM-OPS> 999497
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (1358125)
<DISTRIBUTIONS-OF-GAINS> (2230)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 510295
<NUMBER-OF-SHARES-REDEEMED> (1255432)
<SHARES-REINVESTED> 137132
<NET-CHANGE-IN-ASSETS> (6476951)
<ACCUMULATED-NII-PRIOR> 993531
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> (64010)
<GROSS-ADVISORY-FEES> 77065
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 183071
<AVERAGE-NET-ASSETS> 20354204
<PER-SHARE-NAV-BEGIN> 10.55
<PER-SHARE-NII> 0.80
<PER-SHARE-GAIN-APPREC> (0.23)
<PER-SHARE-DIVIDEND> (0.61)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 10.51
<EXPENSE-RATIO> 0.53
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0
</TABLE>