<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000741375
<NAME> MAS FUNDS
<SERIES>
<NUMBER> 102
<NAME> HIGH YIELD PORTFOLIO, INVESTMENT CLASS
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> SEP-30-2000
<PERIOD-START> OCT-01-1999
<PERIOD-END> SEP-30-2000
<INVESTMENTS-AT-COST> 977,614
<INVESTMENTS-AT-VALUE> 842,397
<RECEIVABLES> 44,701
<ASSETS-OTHER> 72
<OTHER-ITEMS-ASSETS> 62,428
<TOTAL-ASSETS> 949,598
<PAYABLE-FOR-SECURITIES> 7,463
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 60,696
<TOTAL-LIABILITIES> 68,159
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 1,018,008
<SHARES-COMMON-STOCK> 1,290
<SHARES-COMMON-PRIOR> 802
<ACCUMULATED-NII-CURRENT> 35,826
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (39,538)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (132,857)
<NET-ASSETS> 881,439
<DIVIDEND-INCOME> 1,110
<INTEREST-INCOME> 110,547
<OTHER-INCOME> 0
<EXPENSES-NET> (5,603)
<NET-INVESTMENT-INCOME> 106,054
<REALIZED-GAINS-CURRENT> (39,153)
<APPREC-INCREASE-CURRENT> (67,461)
<NET-CHANGE-FROM-OPS> (560)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (754)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 827
<NUMBER-OF-SHARES-REDEEMED> (429)
<SHARES-REINVESTED> 90
<NET-CHANGE-IN-ASSETS> (76,785)
<ACCUMULATED-NII-PRIOR> 29,048
<ACCUMULATED-GAINS-PRIOR> (13,993)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 4,536
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 5,677
<AVERAGE-NET-ASSETS> 1,007,367
<PER-SHARE-NAV-BEGIN> 8.78
<PER-SHARE-NII> 0.88
<PER-SHARE-GAIN-APPREC> (0.89)
<PER-SHARE-DIVIDEND> (0.90)
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 7.87
<EXPENSE-RATIO> 0.71
</TABLE>
