SEI INSTITUTIONAL MANAGED TRUST
NSAR-A, 1999-05-28
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<PAGE>      PAGE  1
000 A000000 03/31/1999
000 C000000 0000804239
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 U
001 A000000 SEI INSTITUTIONAL MANAGED TRUST
001 B000000 811-4878
001 C000000 8003425734
002 A000000 2 OLIVER STREET
002 B000000 BOSTON
002 C000000 MA
002 D010000 02109
003  000000 N
004  000000 N
005  000000 N
006  000000 N
007 A000000 Y
007 B000000 11
007 C010100  1
007 C020100 LARGE CAP VALUE PORTFOLIO
007 C030100 N
007 C010200  2
007 C020200 BALANCED PORTFOLIO
007 C030200 N
007 C010300  3
007 C020300 CAPITAL APPRECIATION PORTFOLIO
007 C030300 N
007 C010400  4
007 C020400 EQUITY INCOME PORTFOLIO
007 C030400 N
007 C010500  5
007 C020500 CORE FIXED INCOME PORTFOLIO
007 C030500 N
007 C010600  6
007 C010700  7
007 C010800  8
007 C020800 SMALL CAP GROWTH PORTFOLIO
007 C030800 N
007 C010900  9
007 C020900 MID-CAP PORTFOLIO
007 C030900 N
007 C011000 10
007 C021000 LARGE CAP GROWTH PORTFOLIO
007 C031000 N
007 C011100 11
007 C021100 SMALL CAP VALUE
007 C031100 N
<PAGE>      PAGE  2
007 C011200 12
007 C021200 HIGH YIELD BOND
007 C031200 N
007 C011300 13
007 C021300 TAX-MANAGED LARGE CAP
007 C031300 N
007 C011400 14
007 C011500 15
007 C011600 16
007 C011700 17
007 C011800 18
007 C011900 19
007 C012000 20
020 A000001 BEAR STEARNS
020 B000001 13-2975144
020 C000001    254
020 A000002 MERRILL LYNCH
020 B000002 13-5674085
020 C000002    237
020 A000003 PERSHING
020 C000003    220
020 A000004 SMITH BARNEY
020 B000004 13-2518466
020 C000004    168
020 A000005 MORGAN STANLEY
020 B000005 13-2655998
020 C000005    146
020 A000006 PAINE WEBBER
020 B000006 13-2760086
020 C000006    145
020 A000007 INSTINET CORPORATION
020 B000007 13-3443395
020 C000007    136
020 A000008 JP MORGAN EQUITIES
020 B000008 13-3224016
020 C000008    130
020 A000009 COMMONWEALTH SECURITIES
020 C000009    114
020 A000010 LEHMAN BROTHERS INC.
020 B000010 13-2927667
020 C000010    100
021  000000     4015
022 A000001 JP MORGAN EQUITIES
022 B000001 13-3224016
022 C000001  28684566
022 D000001   1416150
022 A000002 LEHMAN BROTHERS INC.
022 B000002 13-2927667
022 C000002   7058494
022 D000002    631608
022 A000003 SPEAR, LEADS, KELLOGG
<PAGE>      PAGE  3
022 B000003 13-5515160
022 C000003   2123288
022 D000003      2785
022 A000004 MERRILL LYNCH
022 B000004 13-5674085
022 C000004   1192894
022 D000004    370051
022 A000005 CS FIRST BOSTON
022 B000005 13-5659485
022 C000005    843349
022 D000005    774722
022 A000006 DONALDSON, LUFKIN & JENRETTE
022 C000006    561736
022 D000006    510354
022 A000007 SALOMON BROTHERS
022 B000007 13-1912900
022 C000007    525979
022 D000007    423139
022 A000008 DIRECT
022 C000008    467471
022 D000008         0
022 A000009 GOLDMAN SACHS
022 B000009 13-5108880
022 C000009    332217
022 D000009    134777
022 A000010 BEAR STEARNS
022 B000010 13-2975144
022 C000010    224228
022 D000010    171801
023 C000000   42014222
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<PAGE>      PAGE  4
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<PAGE>      PAGE  5
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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  28
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SIGNATURE   MARK NAGLE
TITLE       CONTROLLER



<TABLE> <S> <C>

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<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 010
   <NAME> LARGE CAP VALUE FUND
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</TABLE>

<TABLE> <S> <C>

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<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
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</TABLE>

<TABLE> <S> <C>

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<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 030
   <NAME> CAPITAL APPRECIATION FUND
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<EXPENSE-RATIO>                                    .84


</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
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   <NUMBER> 040
   <NAME> EQUITY INCOME FUND
<MULTIPLIER> 1,000

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<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 050
   <NAME> CORE FIXED INCOME FUND
<MULTIPLIER> 1,000

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<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 080
   <NAME> SMALL CAP GROWTH FUND CLASS A
<MULTIPLIER> 1,000

<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 081
   <NAME> SMALL CAP GROWTH FUND CLASS D
<MULTIPLIER> 1,000

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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
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   <NAME> MID-CAP FUND
<MULTIPLIER> 1,000

<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
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   <NAME> LARGE CAP GROWTH FUND
<MULTIPLIER> 1,000

<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 110
   <NAME> SMALL CAP VALUE FUND
<MULTIPLIER> 1,000

<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 120
   <NAME> HIGH YIELD BOND FUND
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<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 130
   <NAME> TAX MANAGED LARGE CAP FUND
<MULTIPLIER> 1,000

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