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> 07
<NAME> LSIT HIGH YIELD 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> 36412218
<INVESTMENTS-AT-VALUE> 32927165
<RECEIVABLES> 6867143
<ASSETS-OTHER> 0
<OTHER-ITEMS-ASSETS> 11191
<TOTAL-ASSETS> 39805499
<PAYABLE-FOR-SECURITIES> 128574
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 58420
<TOTAL-LIABILITIES> 186994
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 46011444
<SHARES-COMMON-STOCK> 4753283
<SHARES-COMMON-PRIOR> 3034868
<ACCUMULATED-NII-CURRENT> 2675751
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> (5583490)
<ACCUM-APPREC-OR-DEPREC> (3485200)
<NET-ASSETS> 39618505
<DIVIDEND-INCOME> 275762
<INTEREST-INCOME> 3385886
<OTHER-INCOME> 0
<EXPENSES-NET> (229483)
<NET-INVESTMENT-INCOME> 3432165
<REALIZED-GAINS-CURRENT> (1672712)
<APPREC-INCREASE-CURRENT> 798429
<NET-CHANGE-FROM-OPS> 2557882
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (2737451)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 1505594
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 212821
<NET-CHANGE-IN-ASSETS> 14134408
<ACCUMULATED-NII-PRIOR> 1935682
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> (3865423)
<GROSS-ADVISORY-FEES> 183586
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 314129
<AVERAGE-NET-ASSETS> 30597724
<PER-SHARE-NAV-BEGIN> 8.40
<PER-SHARE-NII> 0.82
<PER-SHARE-GAIN-APPREC> 0.01
<PER-SHARE-DIVIDEND> (0.90)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 8.33
<EXPENSE-RATIO> 0.75
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0
</TABLE>