<PAGE> PAGE 1
000 A000000 06/30/96
000 C000000 0000082345
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0.a
000 J000000 A
001 A000000 MASTER RESERVES TRUST
001 B000000 811-2597
001 C000000 6173383200
002 A000000 200 BERKELEY STREET
002 B000000 BOSTON
002 C000000 MA
002 D010000 02116
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 1
007 C010100 1
007 C020100 MONEY MARKET PORTFOLIOS
007 C030100 N
007 C010200 2
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 KEYSTONE INVESTMENT MANAGEMENT COMPANY
008 B00AA01 A
008 C00AA01 801-8327
008 D01AA01 BOSTON
008 D02AA01 MA
008 D03AA01 02116
008 D04AA01 5034
010 A00AA01 KEYSTONE INVESTMENT, INC.
010 C01AA01 BOSTON
010 C02AA01 MA
010 C03AA01 02116
010 C04AA01 5034
011 A00AA01 KEYSTONE INVESTMENT DISTRIBUTORS, CO
011 B00AA01 8-2597
011 C01AA01 BOSTON
011 C02AA01 MA
011 C03AA01 02116
<PAGE> PAGE 2
011 C04AA01 5034
012 A00AA01 KEYSTONE INVESTOR RESOURCE CENTER
012 B00AA01 84-1571
012 C01AA01 CAMBRIDGE
012 C02AA01 MA
012 C03AA01 02142
013 A00AA01 KPMG PEAT MARWICK, LLP
013 B01AA01 BOSTON
013 B02AA01 MA
013 B03AA01 02110
015 A00AA01 STATE STREET BANK & TRUST COMPANY
015 B00AA01 C
015 C01AA01 BOSTON
015 C02AA01 MA
015 C03AA01 02110
015 E01AA01 X
018 00AA00 Y
019 A00AA00 Y
019 B00AA00 1
019 C00AA00 KEYGROUPIT
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 HSBC SECURITIES
022 C000001 97438
022 D000001 2903
022 A000002 GOLDMAN SACHS
022 C000002 62461
022 D000002 997
022 A000003 MERRILL LYNCH
022 C000003 23552
022 D000003 991
022 A000004 FIRST BOSTON CORP
022 C000004 18394
022 D000004 0
022 A000005 PANE WEBBER
022 C000005 17968
022 D000005 0
022 A000006 SMITH BARNEY SHEARSON
022 C000006 10732
022 D000006 0
022 A000007 CSFIRST BOSTON CORP
022 C000007 9232
<PAGE> PAGE 3
022 D000007 0
022 A000008 AMERICAN EXPRESS CREDIT CORP
022 C000008 8696
022 D000008 0
022 A000009 FIRST BOSTON COMMERICAL PAPER
022 C000009 4430
022 D000009 999
022 A000010 GENERAL ELECTRIC CAPITAL CORP
022 C000010 1964
022 D000010 993
023 C000000 865331
023 D000000 8627
024 00AA00 N
026 A000000 Y
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
034 00AA00 N
035 00AA00 0
036 B00AA00 0
037 00AA00 N
038 00AA00 0
039 00AA00 N
040 00AA00 N
045 00AA00 Y
046 00AA00 N
047 00AA00 Y
048 00AA00 0.090
048 A01AA00 0
048 A02AA00 0.000
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
<PAGE> PAGE 4
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 0
048 K02AA00 0.000
049 00AA00 N
050 00AA00 N
051 00AA00 N
052 00AA00 N
053 A00AA00 N
054 A00AA00 Y
054 B00AA00 Y
054 C00AA00 Y
054 D00AA00 Y
054 E00AA00 Y
054 F00AA00 Y
054 G00AA00 Y
054 H00AA00 Y
054 I00AA00 Y
054 J00AA00 Y
054 K00AA00 Y
054 L00AA00 N
054 M00AA00 Y
054 N00AA00 Y
054 O00AA00 N
058 A00AA00 N
059 00AA00 Y
060 A00AA00 Y
060 B00AA00 Y
061 00AA00 250000
066 A00AA00 N
067 00AA00 N
068 A00AA00 N
068 B00AA00 N
069 00AA00 N
077 A000000 Y
077 B000000 N
077 C000000 N
077 D000000 N
077 E000000 N
077 F000000 N
077 G000000 N
077 H000000 N
077 I000000 N
077 J000000 N
077 K000000 N
077 L000000 N
<PAGE> PAGE 5
077 M000000 N
077 N000000 N
077 O000000 N
077 P000000 N
077 Q010000 Y
077 Q020000 N
077 Q030000 N
078 000000 N
080 C000000 0
080 A00AA00 ICI MUTUAL INSURANCE COMPANY
080 B00AA00 FREDERICK JONES
080 C00AA00 35000
081 B000000 0
081 A00AA00 Y
081 B00AA00 35
082 B000000 0
082 A00AA00 N
082 B00AA00 0
083 A00AA00 N
083 B00AA00 0
084 A00AA00 N
084 B00AA00 0
085 A00AA00 N
085 B00AA00 N
028 A010100 9787
028 A020100 157
028 A030100 0
028 A040100 14119
028 B010100 8696
028 B020100 136
028 B030100 0
028 B040100 5897
028 C010100 7323
028 C020100 140
028 C030100 0
028 C040100 15491
028 D010100 9433
028 D020100 122
028 D030100 0
028 D040100 5562
028 E010100 9705
028 E020100 119
028 E030100 0
028 E040100 4606
028 F010100 6168
028 F020100 154
028 F030100 0
028 F040100 7681
028 G010100 51112
028 G020100 828
028 G030100 0
<PAGE> PAGE 6
028 G040100 53356
028 H000100 0
055 A000100 N
055 B000100 N
056 000100 N
057 000100 N
062 A000100 Y
062 B000100 0.0
062 C000100 22.2
062 D000100 25.8
062 E000100 0.0
062 F000100 2.9
062 G000100 0.0
062 H000100 5.6
062 I000100 47.9
062 J000100 0.0
062 K000100 0.0
062 L000100 1.2
062 M000100 0.0
062 N000100 0.0
062 O000100 0.0
062 P000100 0.0
062 Q000100 0.0
062 R000100 0.0
063 A000100 28
063 B000100 0.0
064 A000100 N
070 A010100 Y
070 A020100 Y
070 B010100 N
070 B020100 N
070 C010100 N
070 C020100 N
070 D010100 N
070 D020100 N
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 Y
070 K020100 N
070 L010100 N
070 L020100 N
<PAGE> PAGE 7
070 M010100 N
070 M020100 N
070 N010100 Y
070 N020100 N
070 O010100 Y
070 O020100 N
070 P010100 Y
070 P020100 N
070 Q010100 N
070 Q020100 N
070 R010100 Y
070 R020100 N
071 A000100 0
071 B000100 0
071 C000100 0
071 D000100 0
072 A000100 6
072 B000100 826
072 C000100 0
072 D000100 0
072 E000100 0
072 F000100 14
072 G000100 0
072 H000100 0
072 I000100 0
072 J000100 0
072 K000100 0
072 L000100 0
072 M000100 0
072 N000100 0
072 O000100 0
072 P000100 0
072 Q000100 0
072 R000100 0
072 S000100 0
072 T000100 0
072 U000100 0
072 V000100 0
072 W000100 0
072 X000100 14
072 Y000100 0
072 Z000100 812
072AA000100 0
072BB000100 0
072CC010100 0
072CC020100 3
072DD010100 812
072DD020100 0
072EE000100 0
073 A010100 0.0260
073 A020100 0.0000
<PAGE> PAGE 8
073 B000100 0.0000
073 C000100 0.0000
074 A000100 40
074 B000100 8900
074 C000100 25685
074 D000100 0
074 E000100 0
074 F000100 0
074 G000100 0
074 H000100 0
074 I000100 0
074 J000100 0
074 K000100 0
074 L000100 15
074 M000100 0
074 N000100 34640
074 O000100 0
074 P000100 7
074 Q000100 0
074 R010100 0
074 R020100 0
074 R030100 0
074 R040100 142
074 S000100 0
074 T000100 34491
074 U010100 34487
074 U020100 0
074 V010100 1.00
074 V020100 0.00
074 W000100 0.0000
074 X000100 1
074 Y000100 0
075 A000100 30959
075 B000100 0
076 000100 0.00
080 A000100 ICI MUTUAL INSRUANCE
080 B000100 SEDGWICK JAMES
080 C000100 35000
081 A000100 Y
081 B000100 35
082 A000100 N
082 B000100 0
083 A000100 N
083 B000100 0
084 A000100 N
084 B000100 0
085 A000100 Y
085 B000100 N
SIGNATURE J. KEVIN KENELY
TITLE TREASURER
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM ACCOUNTING
RECORDS AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH ACCOUNTING
RECORDS.
</LEGEND>
<SERIES>
<NUMBER> 101
<NAME> MASTER RESERVES TRUST CLASS A
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1996
<PERIOD-START> JAN-01-1996
<PERIOD-END> JUL-31-1996
<INVESTMENTS-AT-COST> 34,586,943
<INVESTMENTS-AT-VALUE> 34,584,978
<RECEIVABLES> 15,489
<ASSETS-OTHER> 39,854
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 34,640,321
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 0
<TOTAL-LIABILITIES> 149,432
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 34,483,559
<SHARES-COMMON-STOCK> 34,487,461
<SHARES-COMMON-PRIOR> 35,903,688
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 9,295
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> (1,965)
<NET-ASSETS> 34,490,889
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 825,448
<OTHER-INCOME> 0
<EXPENSES-NET> (13,779)
<NET-INVESTMENT-INCOME> 811,669
<REALIZED-GAINS-CURRENT> 384
<APPREC-INCREASE-CURRENT> (3,303)
<NET-CHANGE-FROM-OPS> 808,750
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (811,669)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 51,112,708
<NUMBER-OF-SHARES-REDEEMED> (53,355,120)
<SHARES-REINVESTED> 826,185
<NET-CHANGE-IN-ASSETS> (1,419,146)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 8,911
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> (13,779)
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> (13,779)
<AVERAGE-NET-ASSETS> 30,958,621
<PER-SHARE-NAV-BEGIN> 1.00
<PER-SHARE-NII> 0.03
<PER-SHARE-GAIN-APPREC> 0.00
<PER-SHARE-DIVIDEND> (0.03)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0.00
<PER-SHARE-NAV-END> 1.00
<EXPENSE-RATIO> 0.09
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
