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<PAGE> PAGE 2
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<PAGE> PAGE 3
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<PAGE> PAGE 4
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<PAGE> PAGE 6
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<PAGE> PAGE 7
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<PAGE> PAGE 8
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<PAGE> PAGE 9
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<PAGE> PAGE 10
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<PAGE> PAGE 11
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<PAGE> PAGE 12
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<PAGE> PAGE 13
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<PAGE> PAGE 14
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<PAGE> PAGE 15
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<PAGE> PAGE 16
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<PAGE> PAGE 17
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<PAGE> PAGE 18
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<PAGE> PAGE 19
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<PAGE> PAGE 20
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<PAGE> PAGE 21
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<PAGE> PAGE 22
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015 A000501 CUSTODIAL TRUST COMPANY
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<PAGE> PAGE 23
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<PAGE> PAGE 24
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<PAGE> PAGE 25
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<PAGE> PAGE 26
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SIGNATURE GARY TENKMAN
TITLE DIRECTOR
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<NAME> BARR ROSENBERG SERIES TRUST, U.S. SMALL CAPITALIZATION SERIES
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<F1>INSTITUTIONAL SHARES
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<TABLE> <S> <C>
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<NAME> BARR ROSENBERG SERIES TRUST, U.S. SMALL CAPITALIZATION SERIES
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<FN>
<F1>ADVISER SHARES
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<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER> 013
<NAME> BARR ROSENBERG SERIES TRUST, U.S. SMALL CAPITALIZATION SERIES
<S> <C>
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<FN>
<F1>SELECT SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER> 021
<NAME> BARR ROSENBERG SERIES TRUST, JAPAN SERIES
<S> <C>
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<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-END> SEP-30-1998
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<FN>
<F1>INSTITUTIONAL SHARES
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<SERIES>
<NUMBER> 022
<NAME> BARR ROSENBERG SERIES TRUST, JAPAN SERIES
<S> <C>
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<ACCUM-APPREC-OR-DEPREC> (186517)
<NET-ASSETS> 957001
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<NET-INVESTMENT-INCOME> (3205)
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<PER-SHARE-NII> (.02)<F1>
<PER-SHARE-GAIN-APPREC> (0.91)<F1>
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<F1>SELECT SHARES
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<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>INSTITUTIONAL SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER> 032
<NAME> BARR ROSENBERG SERIES TRUST, INTERNATIONAL SMALL CAPITALIZATION SERIES
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-END> SEP-30-1998
<INVESTMENTS-AT-COST> 48631577
<INVESTMENTS-AT-VALUE> 39039986
<RECEIVABLES> 1394075
<ASSETS-OTHER> 1320506
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 41754567
<PAYABLE-FOR-SECURITIES> 1556579
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 109233
<TOTAL-LIABILITIES> 1665812
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 49290621
<SHARES-COMMON-STOCK> 252544<F1>
<SHARES-COMMON-PRIOR> 136230<F1>
<ACCUMULATED-NII-CURRENT> 390988
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 29439
<ACCUM-APPREC-OR-DEPREC> (9563415)
<NET-ASSETS> 40088755
<DIVIDEND-INCOME> 693573
<INTEREST-INCOME> 0
<OTHER-INCOME> 0
<EXPENSES-NET> 333716
<NET-INVESTMENT-INCOME> 359857
<REALIZED-GAINS-CURRENT> 365012
<APPREC-INCREASE-CURRENT> (10384396)
<NET-CHANGE-FROM-OPS> (9659527)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0<F1>
<DISTRIBUTIONS-OF-GAINS> 0<F1>
<DISTRIBUTIONS-OTHER> 0<F1>
<NUMBER-OF-SHARES-SOLD> 146051<F1>
<NUMBER-OF-SHARES-REDEEMED> 29737<F1>
<SHARES-REINVESTED> 0<F1>
<NET-CHANGE-IN-ASSETS> (503772)
<ACCUMULATED-NII-PRIOR> 31131
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 394451
<GROSS-ADVISORY-FEES> 224158
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 457333
<AVERAGE-NET-ASSETS> 2113822<F1>
<PER-SHARE-NAV-BEGIN> 10.09<F1>
<PER-SHARE-NII> .05<F1>
<PER-SHARE-GAIN-APPREC> (2.04)<F1>
<PER-SHARE-DIVIDEND> 0<F1>
<PER-SHARE-DISTRIBUTIONS> 0<F1>
<RETURNS-OF-CAPITAL> 0<F1>
<PER-SHARE-NAV-END> 8.10<F1>
<EXPENSE-RATIO> 1.93<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>SELECT SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000832545
<NAME> BARR ROSENBERG SERIES TRUST
<SERIES>
<NUMBER> 041
<NAME> BARR ROSENBERG SERIES TRUST, MARKET NEUTRAL FUND
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-END> SEP-30-1998
<INVESTMENTS-AT-COST> 337480938
<INVESTMENTS-AT-VALUE> 296124167
<RECEIVABLES> 5103558
<ASSETS-OTHER> 292393027
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 593620752
<PAYABLE-FOR-SECURITIES> 5003673
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 279943318
<TOTAL-LIABILITIES> 284946991
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 302825744
<SHARES-COMMON-STOCK> 24659391<F1>
<SHARES-COMMON-PRIOR> 16860138<F1>
<ACCUMULATED-NII-CURRENT> 5587738
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> (15722585)
<ACCUM-APPREC-OR-DEPREC> 15982864
<NET-ASSETS> 308673761
<DIVIDEND-INCOME> 1321660
<INTEREST-INCOME> 7109556
<OTHER-INCOME> 0
<EXPENSES-NET> 4044762
<NET-INVESTMENT-INCOME> 4386454
<REALIZED-GAINS-CURRENT> (13608651)
<APPREC-INCREASE-CURRENT> 15315372
<NET-CHANGE-FROM-OPS> 6093175
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0<F1>
<DISTRIBUTIONS-OF-GAINS> 0<F1>
<DISTRIBUTIONS-OTHER> 0<F1>
<NUMBER-OF-SHARES-SOLD> 12935180<F1>
<NUMBER-OF-SHARES-REDEEMED> 5135927<F1>
<SHARES-REINVESTED> 0<F1>
<NET-CHANGE-IN-ASSETS> 105370978
<ACCUMULATED-NII-PRIOR> 1201284
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 2113934
<GROSS-ADVISORY-FEES> 2636314
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 4400125
<AVERAGE-NET-ASSETS> 228173645<F1>
<PER-SHARE-NAV-BEGIN> 9.97<F1>
<PER-SHARE-NII> .16<F1>
<PER-SHARE-GAIN-APPREC> .08<F1>
<PER-SHARE-DIVIDEND> 0<F1>
<PER-SHARE-DISTRIBUTIONS> 0<F1>
<RETURNS-OF-CAPITAL> 0<F1>
<PER-SHARE-NAV-END> 10.21<F1>
<EXPENSE-RATIO> 2.87<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>INSTITUTIONAL SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000832545
<NAME> BARR ROSENBERG SERIES TRUST
<SERIES>
<NUMBER> 042
<NAME> BARR ROSENBERG SERIES TRUST, MARKET NEUTRAL FUND
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-END> SEP-30-1998
<INVESTMENTS-AT-COST> 337480938
<INVESTMENTS-AT-VALUE> 296124167
<RECEIVABLES> 5103558
<ASSETS-OTHER> 292393027
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 593620752
<PAYABLE-FOR-SECURITIES> 5003673
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 279943318
<TOTAL-LIABILITIES> 284946991
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 302825744
<SHARES-COMMON-STOCK> 5578919<F1>
<SHARES-COMMON-PRIOR> 3537423<F1>
<ACCUMULATED-NII-CURRENT> 5587738
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> (15722585)
<ACCUM-APPREC-OR-DEPREC> 15982864
<NET-ASSETS> 308673761
<DIVIDEND-INCOME> 1321660
<INTEREST-INCOME> 7109556
<OTHER-INCOME> 0
<EXPENSES-NET> 4044762
<NET-INVESTMENT-INCOME> 4386454
<REALIZED-GAINS-CURRENT> (13608651)
<APPREC-INCREASE-CURRENT> 15315372
<NET-CHANGE-FROM-OPS> 6093175
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0<F1>
<DISTRIBUTIONS-OF-GAINS> 0<F1>
<DISTRIBUTIONS-OTHER> 0<F1>
<NUMBER-OF-SHARES-SOLD> 3591443<F1>
<NUMBER-OF-SHARES-REDEEMED> 1549947<F1>
<SHARES-REINVESTED> 0<F1>
<NET-CHANGE-IN-ASSETS> 105370978
<ACCUMULATED-NII-PRIOR> 1201284
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 2113934
<GROSS-ADVISORY-FEES> 2636314
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 4400125
<AVERAGE-NET-ASSETS> 48574889<F1>
<PER-SHARE-NAV-BEGIN> 9.96<F1>
<PER-SHARE-NII> .14<F1>
<PER-SHARE-GAIN-APPREC> .08<F1>
<PER-SHARE-DIVIDEND> 0<F1>
<PER-SHARE-DISTRIBUTIONS> 0<F1>
<RETURNS-OF-CAPITAL> 0<F1>
<PER-SHARE-NAV-END> 10.18<F1>
<EXPENSE-RATIO> 3.32<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>INVESTOR SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000832545
<NAME> BARR ROSENBERG SERIES TRUST
<SERIES>
<NUMBER> 051
<NAME> BARR ROSENBERG SERIES TRUST, DOUBLE ALPHA FUND
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-START> APR-22-1998
<PERIOD-END> SEP-30-1998
<INVESTMENTS-AT-COST> 7018562
<INVESTMENTS-AT-VALUE> 7104504
<RECEIVABLES> 239026
<ASSETS-OTHER> 14131
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 7357661
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 103781
<TOTAL-LIABILITIES> 103781
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 8118361
<SHARES-COMMON-STOCK> 793666<F1>
<SHARES-COMMON-PRIOR> 0<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 5075
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 1228398
<ACCUM-APPREC-OR-DEPREC> 368992
<NET-ASSETS> 7253880
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 5471
<OTHER-INCOME> 0
<EXPENSES-NET> 10546
<NET-INVESTMENT-INCOME> (5075)
<REALIZED-GAINS-CURRENT> (1228398)
<APPREC-INCREASE-CURRENT> 368992
<NET-CHANGE-FROM-OPS> (864481)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0<F1>
<DISTRIBUTIONS-OF-GAINS> 0<F1>
<DISTRIBUTIONS-OTHER> 0<F1>
<NUMBER-OF-SHARES-SOLD> 1004240<F1>
<NUMBER-OF-SHARES-REDEEMED> 210574<F1>
<SHARES-REINVESTED> 0<F1>
<NET-CHANGE-IN-ASSETS> 7253880
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2914
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 72854
<AVERAGE-NET-ASSETS> 6490542<F1>
<PER-SHARE-NAV-BEGIN> 10.00<F1>
<PER-SHARE-NII> (0.07)<F1>
<PER-SHARE-GAIN-APPREC> (1.03)<F1>
<PER-SHARE-DIVIDEND> 0<F1>
<PER-SHARE-DISTRIBUTIONS> 0<F1>
<RETURNS-OF-CAPITAL> 0<F1>
<PER-SHARE-NAV-END> 8.90<F1>
<EXPENSE-RATIO> 0.35<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>INSTITUTIONAL SHARES
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000832545
<NAME> BARR ROSENBERG SERIES TRUST
<SERIES>
<NUMBER> 052
<NAME> BARR ROSENBERG SERIES TRUST, DOUBLE ALPHA FUND
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1999
<PERIOD-START> APR-22-1998
<PERIOD-END> SEP-30-1998
<INVESTMENTS-AT-COST> 7018562
<INVESTMENTS-AT-VALUE> 7104504
<RECEIVABLES> 239026
<ASSETS-OTHER> 14131
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 7357661
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 103781
<TOTAL-LIABILITIES> 103781
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 8118361
<SHARES-COMMON-STOCK> 21481<F1>
<SHARES-COMMON-PRIOR> 0<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 5075
<ACCUMULATED-NET-GAINS> 0
<OVERDISTRIBUTION-GAINS> 1228398
<ACCUM-APPREC-OR-DEPREC> 368992
<NET-ASSETS> 7253880
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 5471
<OTHER-INCOME> 0
<EXPENSES-NET> 10546
<NET-INVESTMENT-INCOME> (5075)
<REALIZED-GAINS-CURRENT> (1228398)
<APPREC-INCREASE-CURRENT> 368992
<NET-CHANGE-FROM-OPS> (864481)
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0<F1>
<DISTRIBUTIONS-OF-GAINS> 0<F1>
<DISTRIBUTIONS-OTHER> 0<F1>
<NUMBER-OF-SHARES-SOLD> 41424<F1>
<NUMBER-OF-SHARES-REDEEMED> 19943<F1>
<SHARES-REINVESTED> 0<F1>
<NET-CHANGE-IN-ASSETS> 7253880
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2914
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 72854
<AVERAGE-NET-ASSETS> 157797<F1>
<PER-SHARE-NAV-BEGIN> 10.00<F1>
<PER-SHARE-NII> (0.09)<F1>
<PER-SHARE-GAIN-APPREC> (1.02)<F1>
<PER-SHARE-DIVIDEND> 0<F1>
<PER-SHARE-DISTRIBUTIONS> 0<F1>
<RETURNS-OF-CAPITAL> 0<F1>
<PER-SHARE-NAV-END> 8.89<F1>
<EXPENSE-RATIO> 0.66<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>INVESTOR SHARES
</FN>
</TABLE>
