SEI INSTITUTIONAL MANAGED TRUST
NSAR-A, 1998-05-29
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<PAGE>      PAGE  1
000 A000000 03/31/98
000 C000000 0000804239
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0.a
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 12
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 C020600 BOND PORTFOLIO
007 C030600 Y
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
<PAGE>      PAGE  2
007 C021100 SMALL CAP VALUE
007 C031100 N
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 BROADCOURT
020 B000001 13-3144415
020 C000001    237
020 A000002 PERSHING
020 B000002 13-2741729
020 C000002    167
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020 A000004 J.P. MORGAN
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020 A000006 BEAR STEARNS
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020 C000006    114
020 A000007 DLJ
020 C000007    114
020 A000008 MERRILL LYNCH
020 B000008 13-5674085
020 C000008    100
020 A000009 SHAWMUT BANK
020 B000009 06-1212629
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020 A000010 SMITH BARNEY
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020 C000010     79
021  000000     3397
022 A000001 J.P. MORGAN
022 B000001 13-3224016
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022 B000002 13-2927667
<PAGE>      PAGE  3
022 C000002   9160916
022 D000002    591545
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022 D000003    531524
022 A000004 FUJI BANK
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022 C000006    323477
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022 A000007 FORD MOTOR CREDIT
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022 A000008 NOMURA
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022 C000008    113962
022 D000008     96061
022 A000009 FIRST BOSTON
022 B000009 13-5659485
022 C000009     95154
022 D000009    113031
022 A000010 PRUDENTIAL
022 B000010 22-2347336
022 C000010    148389
022 D000010     27827
023 C000000   21848674
023 D000000    3518340
026 A000000 N
026 B000000 Y
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 N
026 G010000 N
026 G020000 N
026 H000000 N
027  000000 Y
077 A000000 N
008 A000101 SEI INVESTMENTS MANAGEMENT CORPORATION
008 B000101 A
008 C000101 801-24593
008 D010101 WAYNE
<PAGE>      PAGE  4
008 D020101 PA
008 D030101 19087
008 A000102 MELLON EQUITY ADVISERS
008 B000102 S
008 C000102 801-28692
008 D010102 PITTSBURGH
008 D020102 PA
008 D030102 15219
008 A000103 LSV ASSET MANAGEMENT
008 B000103 S
008 C000103 801-38734
008 D010103 CHICAGO
008 D020103 IL
008 D030103 60602
008 A000104 SANFORD BERNSTEIN
008 B000104 S
008 C000104 801-0000
008 D010104 NEW YORK
008 D020104 NY
008 D030104 10153
024  000100 Y
025 A000101 BEAR STEARNS
025 B000101 13-2975144
025 C000101 E
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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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075 B000100   996110
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008 A000201 SEI INVESTMENTS MANAGEMENT CORPORATION
008 B000201 A
008 C000201 801-24593
008 D010201 WAYNE
008 D020201 PA
008 D030201 19087
008 A000202 STI CAPITAL MANAGEMENT, N.A.
008 B000202 S
008 C000202 801-0000
008 D010202 ORLANDO
008 D020202 FL
008 D030202 32802
024  000200 Y
025 A000201 J.P. MORGAN
025 B000201 13-3224016
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<PAGE>      PAGE  8
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042 D000200   0
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043  000200      4
044  000200      0
062 A000200 N
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<PAGE>      PAGE  9
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<PAGE>      PAGE  10
074 W000200   0.0000
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075 B000200    50950
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008 A000301 SEI INVESTMENTS MANAGEMENT CORPORATION
008 B000301 A
008 C000301 801-24593
008 D010301 WAYNE
008 D020301 PA
008 D030301 19087
008 D040301 1658
008 A000302 STI CAPITAL MANAGEMENT, N.A.
008 B000302 S
008 C000302 801-0000
008 D010302 ORLANDO
008 D020302 FL
008 D030302 32802
024  000300 Y
025 A000301 LEHMAN BROTHERS
025 B000301 13-2927667
025 C000301 D
025 D000301   21495
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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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008 A000401 SEI INVESTMENTS MANAGEMENT CORPORATION
008 B000401 A
008 C000401 801-24593
008 D010401 WAYNE
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008 D030401 19087
008 D040401 1658
008 A000402 PACIFIC ALLIANCE CAPITAL MANAGEMENT
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008 C000402 801-0000
008 D010402 SAN FRANCISCO
008 D020402 CA
008 D030402 94111
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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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008 A000501 SEI INVESTMENTS MANAGEMENT CORPORATION
008 B000501 A
008 C000501 801-24593
008 D010501 WAYNE
008 D020501 PA
008 D030501 19087
008 D040501 1658
008 A000502 WESTERN ASSET MANAGEMENT
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008 C000502 801-08162
008 D010502 PASADENA
008 D020502 CA
008 D030502 91105
008 A000503 BLACKROCK FINANCIAL MANAGEMENT INC.
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008 A000504 FIRSTAR INVESTMENT RESEARCH & MNGT CO.
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<PAGE>      PAGE  17
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<PAGE>      PAGE  18
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<PAGE>      PAGE  37
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<PAGE>      PAGE  38
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066 E001300 N
066 F001300 N
066 G001300 N
067  001300 N
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068 B001300 N
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070 C021300 N
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070 E021300 N
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070 N011300 N
070 N021300 N
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SIGNATURE   MARK NAGLE                                   
TITLE       CONTROLLER          
 


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<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
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<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
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<CIK> 0000804239
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<CIK> 0000804239
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<TABLE> <S> <C>

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<CIK> 0000804239
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</TABLE>

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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 082
   <NAME> SMALL CAP GROWTH CLASS D
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<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
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   <NUMBER> 090
   <NAME> MID CAP
<MULTIPLIER> 1,000
       
<S>                             <C>
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 100
   <NAME> LARGE CAP GROWTH
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<S>                             <C>
<PERIOD-TYPE>                   6-MOS
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</TABLE>

<TABLE> <S> <C>

<ARTICLE> 6
<CIK> 0000804239
<NAME> SEI INSTITUTIONAL MANAGED TRUST
<SERIES>
   <NUMBER> 110
   <NAME> SMALL CAP VALUE
<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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   <NUMBER> 120
   <NAME> HIGH YIELD BOND
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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
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<S>                             <C>
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</TABLE>


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