<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000939934
<NAME> SEI INSTITUTIONAL INVESTMENTS TRUST
<SERIES>
<NUMBER> 010
<NAME> LARGE CAP FUND
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> YEAR
<FISCAL-YEAR-END> MAY-31-2000
<PERIOD-START> JUN-01-1999
<PERIOD-END> MAY-31-2000
<INVESTMENTS-AT-COST> 2663570
<INVESTMENTS-AT-VALUE> 3164193
<RECEIVABLES> 48309
<ASSETS-OTHER> 59
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 3212561
<PAYABLE-FOR-SECURITIES> 25164
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3171
<TOTAL-LIABILITIES> 28335
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 2606637
<SHARES-COMMON-STOCK> 163477
<SHARES-COMMON-PRIOR> 88722
<ACCUMULATED-NII-CURRENT> 5609
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 71499
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 500481
<NET-ASSETS> 3184226
<DIVIDEND-INCOME> 31098
<INTEREST-INCOME> 3806
<OTHER-INCOME> 0
<EXPENSES-NET> (6635)
<NET-INVESTMENT-INCOME> 28269
<REALIZED-GAINS-CURRENT> 130256
<APPREC-INCREASE-CURRENT> 70318
<NET-CHANGE-FROM-OPS> 228843
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (25350)
<DISTRIBUTIONS-OF-GAINS> (111074)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 97353
<NUMBER-OF-SHARES-REDEEMED> (29679)
<SHARES-REINVESTED> 7081
<NET-CHANGE-IN-ASSETS> 1514281
<ACCUMULATED-NII-PRIOR> 2690
<ACCUMULATED-GAINS-PRIOR> 51225
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 14290
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 12073
<AVERAGE-NET-ASSETS> 2525965
<PER-SHARE-NAV-BEGIN> 18.82
<PER-SHARE-NII> 0.20
<PER-SHARE-GAIN-APPREC> 1.48
<PER-SHARE-DIVIDEND> (0.19)
<PER-SHARE-DISTRIBUTIONS> (0.83)
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 19.48
<EXPENSE-RATIO> 0.26
</TABLE>
