<PAGE> PAGE 1
000 A000000 06/30/98
000 C000000 931312
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0
000 J000000 A
001 A000000 THE EXPLORER INSTITUTIONAL TRUST
001 B000000 811-8808
001 C000000 6306846000
002 A000000 ONE PARKVIEW PLAZA
002 B000000 OAKBROOK TERRACE
002 C000000 IL
002 D010000 60181
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 2
007 C010100 1
007 C020100 EXPLORER INSTITUTIONAL ACTIVE CORE FUND
007 C030100 N
007 C010200 2
007 C020200 EXPLORER INSTITUTIONAL LIMITED DURATION FUND
007 C030200 N
007 C010300 3
007 C010400 4
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A00AA01 VAN KAMPEN AMERICAN CAPITAL MANAGEMENT, INC.
008 B00AA01 A
008 C00AA01 801-8286
008 D01AA01 OAKBROOK TERACE
008 D02AA01 IL
008 D03AA01 60181
011 A00AA01 VAN KAMPEN AMERICAN CAPITAL DISTRIBUTORS, INC
011 B00AA01 8-19412
011 C01AA01 OAKBROOK TERRACE
011 C02AA01 IL
011 C03AA01 60181
012 A00AA01 ACCESS INVESTOR SERVICES, INC
012 B00AA01 85-5003
012 C01AA01 KANSAS CITY
012 C02AA01 MO
<PAGE> PAGE 2
012 C03AA01 64141
013 A00AA01 KPMG PEAT MARWICK LLP
013 B01AA01 CHICAGO
013 B02AA01 IL
013 B03AA01 60601
014 A00AA01 MORGAN STANLEY & CO., INCORPORATED
014 B00AA01 8-00733537
014 A00AA02 DEAN WITTER REYNOLDS, INC.
014 B00AA02 8-00728181
015 A00AA01 STATE STREET BANK AND TRUST COMPANY
015 B00AA01 C
015 C01AA01 BOSTON
015 C02AA01 MA
015 C03AA01 02105
015 E01AA01 X
018 00AA00 Y
019 A00AA00 Y
019 B00AA00 117
019 C00AA00 VANKAMPENA
020 C000001 0
020 C000002 0
020 C000003 0
020 C000004 0
020 C000005 0
020 C000006 0
020 C000007 0
020 C000008 0
020 C000009 0
020 C000010 0
021 000000 0
022 A000001 FUJI SECURITIES, INC
022 C000001 95894
022 D000001 875
022 A000002 HONG KONG SHANGHAI (HSBC)
022 B000002 13-2650272
022 C000002 1883
022 D000002 2875
022 A000003 PAINE WEBBER
022 B000003 13-2638166
022 C000003 1838
022 D000003 1257
022 A000004 FIRST CHICAGO CAPITAL MKTS
022 B000004 36-3595942
022 C000004 1435
022 D000004 895
022 A000005 DONALDSON LUFKIN JENNRETTE
022 B000005 13-2741729
022 C000005 1513
022 D000005 0
022 A000006 FIRST BOSTON
022 B000006 13-5659485
<PAGE> PAGE 3
022 C000006 684
022 D000006 588
022 A000007 LEHMAN BROTHERS INC.
022 B000007 13-2518466
022 C000007 506
022 D000007 633
022 A000008 UBS SECURITIES
022 B000008 13-2932996
022 C000008 887
022 D000008 0
022 A000009 BEAR STEARNS
022 B000009 13-3299429
022 C000009 358
022 D000009 173
022 A000010 GOLDMAN SACHS
022 B000010 13-5108880
022 C000010 428
022 D000010 50
023 C000000 106063
023 D000000 7751
024 00AA00 N
025 D00AA01 0
025 D00AA02 0
025 D00AA03 0
025 D00AA04 0
025 D00AA05 0
025 D00AA06 0
025 D00AA07 0
025 D00AA08 0
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
029 00AA00 N
030 A00AA00 0
030 B00AA00 0.00
030 C00AA00 0.00
031 A00AA00 0
031 B00AA00 0
032 00AA00 0
033 00AA00 0
034 00AA00 N
035 00AA00 0
036 B00AA00 0
037 00AA00 N
<PAGE> PAGE 4
038 00AA00 0
039 00AA00 N
040 00AA00 N
042 A00AA00 0
042 B00AA00 0
042 C00AA00 0
042 D00AA00 0
042 E00AA00 0
042 F00AA00 0
042 G00AA00 0
042 H00AA00 0
043 00AA00 0
044 00AA00 0
045 00AA00 Y
046 00AA00 N
047 00AA00 Y
048 00AA00 0.000
048 A01AA00 1000000
048 A02AA00 0.300
048 B01AA00 0
048 B02AA00 0.000
048 C01AA00 0
048 C02AA00 0.000
048 D01AA00 0
048 D02AA00 0.000
048 E01AA00 0
048 E02AA00 0.000
048 F01AA00 0
048 F02AA00 0.000
048 G01AA00 0
048 G02AA00 0.000
048 H01AA00 0
048 H02AA00 0.000
048 I01AA00 0
048 I02AA00 0.000
048 J01AA00 0
048 J02AA00 0.000
048 K01AA00 1000000
048 K02AA00 0.250
049 00AA00 N
050 00AA00 N
051 00AA00 N
052 00AA00 N
053 A00AA00 Y
053 B00AA00 N
053 C00AA00 Y
054 A00AA00 Y
054 B00AA00 N
054 C00AA00 N
054 D00AA00 N
054 E00AA00 N
<PAGE> PAGE 5
054 F00AA00 N
054 G00AA00 Y
054 H00AA00 N
054 I00AA00 Y
054 J00AA00 N
054 K00AA00 N
054 L00AA00 N
054 M00AA00 N
054 N00AA00 N
054 O00AA00 N
055 A00AA00 N
055 B00AA00 N
056 00AA00 Y
057 00AA00 N
058 A00AA00 N
059 00AA00 Y
060 A00AA00 Y
060 B00AA00 Y
061 00AA00 500
066 A00AA00 N
067 00AA00 N
068 A00AA00 N
068 B00AA00 N
069 00AA00 N
077 A000000 N
078 000000 N
080 C00AA00 0
081 B00AA00 0
082 B00AA00 0
083 B00AA00 0
084 B00AA00 0
086 A010000 0
086 A020000 0
086 B010000 0
086 B020000 0
086 C010000 0
086 C020000 0
086 D010000 0
086 D020000 0
086 E010000 0
086 E020000 0
086 F010000 0
086 F020000 0
028 A010100 1500
028 A020100 50
028 A030100 0
028 A040100 0
028 B010100 5500
028 B020100 40
028 B030100 0
028 B040100 35
<PAGE> PAGE 6
028 C010100 15
028 C020100 56
028 C030100 0
028 C040100 200
028 D010100 0
028 D020100 54
028 D030100 0
028 D040100 0
028 E010100 0
028 E020100 55
028 E030100 0
028 E040100 0
028 F010100 0
028 F020100 54
028 F030100 0
028 F040100 200
028 G010100 7015
028 G020100 309
028 G030100 0
028 G040100 435
028 H000100 0
062 A000100 Y
062 B000100 0.0
062 C000100 4.1
062 D000100 0.0
062 E000100 0.0
062 F000100 0.0
062 G000100 0.0
062 H000100 0.0
062 I000100 0.0
062 J000100 0.0
062 K000100 0.0
062 L000100 0.0
062 M000100 34.2
062 N000100 34.5
062 O000100 0.0
062 P000100 16.9
062 Q000100 9.1
062 R000100 0.0
063 A000100 0
063 B000100 6.8
064 A000100 N
064 B000100 N
070 A010100 Y
070 A020100 N
070 B010100 N
070 B020100 N
070 C010100 N
070 C020100 N
070 D010100 N
070 D020100 N
<PAGE> PAGE 7
070 E010100 N
070 E020100 N
070 F010100 N
070 F020100 N
070 G010100 N
070 G020100 N
070 H010100 N
070 H020100 N
070 I010100 N
070 I020100 N
070 J010100 Y
070 J020100 N
070 K010100 N
070 K020100 N
070 L010100 N
070 L020100 N
070 M010100 N
070 M020100 N
070 N010100 N
070 N020100 N
070 O010100 Y
070 O020100 N
070 P010100 Y
070 P020100 N
070 Q010100 N
070 Q020100 N
070 R010100 N
070 R020100 N
071 A000100 12400
071 B000100 6035
071 C000100 9415
071 D000100 64
072 A000100 6
072 B000100 306
072 C000100 0
072 D000100 0
072 E000100 0
072 F000100 15
072 G000100 0
072 H000100 0
072 I000100 8
072 J000100 9
072 K000100 0
072 L000100 3
072 M000100 4
072 N000100 1
072 O000100 0
072 P000100 0
072 Q000100 7
072 R000100 6
072 S000100 0
<PAGE> PAGE 8
072 T000100 0
072 U000100 5
072 V000100 0
072 W000100 11
072 X000100 69
072 Y000100 49
072 Z000100 286
072AA000100 19
072BB000100 0
072CC010100 26
072CC020100 0
072DD010100 286
072DD020100 0
072EE000100 25
073 A010100 0.2870
073 A020100 0.0000
073 B000100 0.0220
073 C000100 0.0000
074 A000100 0
074 B000100 0
074 C000100 484
074 D000100 11224
074 E000100 0
074 F000100 0
074 G000100 0
074 H000100 0
074 I000100 0
074 J000100 0
074 K000100 6
074 L000100 116
074 M000100 27
074 N000100 11857
074 O000100 0
074 P000100 0
074 Q000100 0
074 R010100 0
074 R020100 0
074 R030100 0
074 R040100 10
074 S000100 0
074 T000100 11847
074 U010100 1158
074 U020100 0
074 V010100 10.23
074 V020100 0.00
074 W000100 0.0000
074 X000100 9
074 Y000100 0
075 A000100 0
075 B000100 10215
076 000100 0.00
<PAGE> PAGE 9
028 A010200 250
028 A020200 40
028 A030200 0
028 A040200 6088
028 B010200 0
028 B020200 11
028 B030200 0
028 B040200 0
028 C010200 0
028 C020200 11
028 C030200 0
028 C040200 0
028 D010200 0
028 D020200 11
028 D030200 0
028 D040200 0
028 E010200 50
028 E020200 11
028 E030200 0
028 E040200 0
028 F010200 0
028 F020200 11
028 F030200 0
028 F040200 0
028 G010200 300
028 G020200 95
028 G030200 0
028 G040200 6088
028 H000200 0
062 A000200 Y
062 B000200 0.0
062 C000200 4.7
062 D000200 0.0
062 E000200 0.0
062 F000200 0.0
062 G000200 0.0
062 H000200 0.0
062 I000200 0.0
062 J000200 0.0
062 K000200 0.0
062 L000200 0.0
062 M000200 40.9
062 N000200 5.1
062 O000200 0.0
062 P000200 20.7
062 Q000200 5.1
062 R000200 0.0
063 A000200 0
063 B000200 1.2
064 A000200 N
064 B000200 N
<PAGE> PAGE 10
070 A010200 Y
070 A020200 N
070 B010200 N
070 B020200 N
070 C010200 N
070 C020200 N
070 D010200 N
070 D020200 N
070 E010200 N
070 E020200 N
070 F010200 N
070 F020200 N
070 G010200 N
070 G020200 N
070 H010200 N
070 H020200 N
070 I010200 N
070 I020200 N
070 J010200 N
070 J020200 N
070 K010200 Y
070 K020200 N
070 L010200 N
070 L020200 N
070 M010200 N
070 M020200 N
070 N010200 N
070 N020200 N
070 O010200 Y
070 O020200 N
070 P010200 N
070 P020200 N
070 Q010200 N
070 Q020200 N
070 R010200 N
070 R020200 N
071 A000200 1637
071 B000200 6485
071 C000200 3046
071 D000200 54
072 A000200 6
072 B000200 119
072 C000200 0
072 D000200 0
072 E000200 0
072 F000200 6
072 G000200 0
072 H000200 0
072 I000200 8
072 J000200 8
072 K000200 0
<PAGE> PAGE 11
072 L000200 0
072 M000200 4
072 N000200 1
072 O000200 0
072 P000200 0
072 Q000200 5
072 R000200 9
072 S000200 10
072 T000200 0
072 U000200 5
072 V000200 0
072 W000200 3
072 X000200 59
072 Y000200 51
072 Z000200 111
072AA000200 88
072BB000200 0
072CC010200 0
072CC020200 61
072DD010200 111
072DD020200 0
072EE000200 0
073 A010200 0.2800
073 A020200 0.0000
073 B000200 0.0000
073 C000200 0.0000
074 A000200 1
074 B000200 0
074 C000200 681
074 D000200 1842
074 E000200 0
074 F000200 0
074 G000200 0
074 H000200 0
074 I000200 0
074 J000200 0
074 K000200 1
074 L000200 23
074 M000200 27
074 N000200 2575
074 O000200 0
074 P000200 0
074 Q000200 0
074 R010200 0
074 R020200 0
074 R030200 0
074 R040200 9
074 S000200 0
074 T000200 2566
074 U010200 255
074 U020200 0
<PAGE> PAGE 12
074 V010200 10.04
074 V020200 0.00
074 W000200 0.0000
074 X000200 6
074 Y000200 0
075 A000200 0
075 B000200 4043
076 000200 0.00
SIGNATURE NICK DALMASO
TITLE ATTORNEY
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER> 11
<NAME> ACTIVE CORE
<MULTIPLIER> 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-START> JAN-01-1998
<PERIOD-END> JUN-30-1998
<INVESTMENTS-AT-COST> 11,528,607
<INVESTMENTS-AT-VALUE> 11,707,412
<RECEIVABLES> 122,286
<ASSETS-OTHER> 27,107
<OTHER-ITEMS-ASSETS> 106
<TOTAL-ASSETS> 11,856,911
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 9,548
<TOTAL-LIABILITIES> 9,548
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 11,652,966
<SHARES-COMMON-STOCK> 1,157,628
<SHARES-COMMON-PRIOR> 485,509
<ACCUMULATED-NII-CURRENT> (3,605)
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 19,197
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 178,805
<NET-ASSETS> 11,847,363
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 305,812
<OTHER-INCOME> 0
<EXPENSES-NET> (20,263)
<NET-INVESTMENT-INCOME> 285,549
<REALIZED-GAINS-CURRENT> 19,379
<APPREC-INCREASE-CURRENT> 25,568
<NET-CHANGE-FROM-OPS> 330,496
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (285,556)
<DISTRIBUTIONS-OF-GAINS> (25,486)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 684,404
<NUMBER-OF-SHARES-REDEEMED> (42,650)
<SHARES-REINVESTED> 30,365
<NET-CHANGE-IN-ASSETS> 6,909,090
<ACCUMULATED-NII-PRIOR> (3,598)
<ACCUMULATED-GAINS-PRIOR> 25,304
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 15,196
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 69,136
<AVERAGE-NET-ASSETS> 10,215,451
<PER-SHARE-NAV-BEGIN> 10.171
<PER-SHARE-NII> 0.292
<PER-SHARE-GAIN-APPREC> 0.080
<PER-SHARE-DIVIDEND> (0.287)
<PER-SHARE-DISTRIBUTIONS> (0.022)
<RETURNS-OF-CAPITAL> 0.000
<PER-SHARE-NAV-END> 10.234
<EXPENSE-RATIO> 0.54
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER> 21
<NAME> LIMITED DURATION
<MULTIPLIER> 1
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1998
<PERIOD-START> JAN-01-1998
<PERIOD-END> JUN-30-1998
<INVESTMENTS-AT-COST> 2,504,857
<INVESTMENTS-AT-VALUE> 2,522,651
<RECEIVABLES> 24,199
<ASSETS-OTHER> 27,676
<OTHER-ITEMS-ASSETS> 645
<TOTAL-ASSETS> 2,575,171
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 9,537
<TOTAL-LIABILITIES> 9,537
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 2,461,612
<SHARES-COMMON-STOCK> 255,481
<SHARES-COMMON-PRIOR> 820,195
<ACCUMULATED-NII-CURRENT> (1,541)
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 87,769
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 17,794
<NET-ASSETS> 2,565,634
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 119,373
<OTHER-INCOME> 0
<EXPENSES-NET> (8,020)
<NET-INVESTMENT-INCOME> 111,353
<REALIZED-GAINS-CURRENT> 87,769
<APPREC-INCREASE-CURRENT> (61,210)
<NET-CHANGE-FROM-OPS> 137,912
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (111,353)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 29,810
<NUMBER-OF-SHARES-REDEEMED> (603,961)
<SHARES-REINVESTED> 9,437
<NET-CHANGE-IN-ASSETS> (5,666,452)
<ACCUMULATED-NII-PRIOR> (1,541)
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 6,014
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 59,452
<AVERAGE-NET-ASSETS> 4,043,082
<PER-SHARE-NAV-BEGIN> 10.037
<PER-SHARE-NII> 0.276
<PER-SHARE-GAIN-APPREC> 0.009
<PER-SHARE-DIVIDEND> (0.280)
<PER-SHARE-DISTRIBUTIONS> 0.000
<RETURNS-OF-CAPITAL> 0.000
<PER-SHARE-NAV-END> 10.042
<EXPENSE-RATIO> 0.76
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
