<PAGE> PAGE 1
000 B000000 12/31/96
000 C000000 0000275694
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 MASSMUTUAL CORPORATE INVESTORS
001 B000000 811-2183
001 C000000 4137888411
002 A000000 1295 STATE STREET
002 B000000 SPRINGFIELD
002 C000000 MA
002 D010000 01111
002 D020000 0001
003 000000 N
004 000000 N
005 000000 N
006 000000 N
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007 C010400 4
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A000001 MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
008 B000001 A
008 C000001 801-8059
008 D010001 SPRINGFIELD
008 D020001 MA
008 D030001 01111
008 D040001 0001
012 A000001 SHAREHOLDER FINANCIAL SERVICES, INC.
012 B000001 84-1817
012 C010001 DENVER
012 C020001 CO
012 C030001 80231
013 A000001 COOPERS & LYBRAND L.L.P.
013 B010001 SPRINGFIELD
013 B020001 MA
013 B030001 01101
015 A000001 THE CHASE MANHATTAN BANK, N.A.
015 B000001 C
<PAGE> PAGE 2
015 C010001 BROOKLYN
015 C020001 NY
015 C030001 11245
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 31
019 C000000 MASSMUTUAL
020 A000001 JONES & ASSOCIATES, INC.
020 B000001 95-3583143
020 C000001 15
020 A000002 DONALDSON, LUFKIN & JENRETTE SECURITIES CORP.
020 B000002 13-2741729
020 C000002 8
020 A000003 ALLEN & COMPANY INCORPORATED
020 B000003 13-6176976
020 C000003 6
020 A000004 JANNEY MONTGOMERY SCOTT INC.
020 B000004 23-0731260
020 C000004 5
020 A000005 CREDIT SUISSE FIRST BOSTON CORPORATION
020 B000005 13-5659485
020 C000005 5
020 A000006 LEGG MASON WOOD WALKER, INC.
020 B000006 52-0902557
020 C000006 5
020 A000007 GRUNTAL & CO., INCORPORATED
020 B000007 13-3179859
020 C000007 4
020 A000008 WEEDEN & CO. L.P.
020 B000008 13-3364318
020 C000008 3
020 A000009 ADVEST INC.
020 B000009 06-0950348
020 C000009 3
020 A000010 WASSERSTEIN PERELLA SECURITIES, INC.
020 B000010 13-3502273
020 C000010 2
021 000000 70
022 A000001 MERRILL LYNCH, PIERCE, FENNER & SMITH, INC.
022 B000001 13-5674085
022 C000001 153351
022 D000001 14697
022 A000002 GOLDMAN, SACHS & CO.
022 B000002 13-5108880
022 C000002 61447
022 D000002 6429
022 A000003 LEHMAN BROTHERS, INC.
022 B000003 13-2518466
022 C000003 50063
022 D000003 7071
<PAGE> PAGE 3
022 A000004 DONALDSON, LUFKIN & JENRETTE SECURITIES CORP.
022 B000004 13-2741729
022 C000004 8538
022 D000004 7083
022 A000005 GRANTCHESTER SECURITIES, INC.
022 C000005 2741
022 D000005 11816
022 A000006 MORGAN (J.P.) SECURITIES INC.
022 B000006 13-3224016
022 C000006 11000
022 D000006 461
022 A000007 JEFFERIES & CO.
022 B000007 95-2622900
022 C000007 2335
022 D000007 6205
022 A000008 BT SECURITIES, INC.
022 B000008 13-3311934
022 C000008 4179
022 D000008 1719
022 A000009 BA SECURITIES, INC.
022 B000009 95-4035346
022 C000009 5800
022 D000009 0
022 A000010 SALOMON BROTHERS INC
022 B000010 13-3082694
022 C000010 4183
022 D000010 250
023 C000000 317788
023 D000000 65407
024 000000 Y
025 A000001 MERRILL LYNCH & CO.
025 B000001 13-2740599
025 C000001 D
025 D000001 590
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
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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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SIGNATURE STEPHEN L. KUHN
TITLE SECRETARY
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
THE SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
ANNUAL REPORT TO SHAREHOLDERS OF MASSMUTUAL CORPORATE INVESTORS FOR THE
YEAR ENDED DECEMBER 31, 1996 AND IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0000275694
<NAME> MASSMUTUAL CORPORATE INVESTORS
<S> <C>
<PERIOD-TYPE> YEAR
<FISCAL-YEAR-END> DEC-31-1996
<PERIOD-START> JAN-01-1996
<PERIOD-END> DEC-31-1996
<INVESTMENTS-AT-COST> 190,473,181
<INVESTMENTS-AT-VALUE> 202,429,621
<RECEIVABLES> 3,698,935
<ASSETS-OTHER> 83,336
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 206,211,892
<PAYABLE-FOR-SECURITIES> 348,125
<SENIOR-LONG-TERM-DEBT> 20,000,000
<OTHER-ITEMS-LIABILITIES> 13,594,554
<TOTAL-LIABILITIES> 33,942,679
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 98,590,717
<SHARES-COMMON-STOCK> 4,256,724
<SHARES-COMMON-PRIOR> 4,256,724
<ACCUMULATED-NII-CURRENT> 17,789
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 11,534,608
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 11,956,440
<NET-ASSETS> 172,269,213
<DIVIDEND-INCOME> 323,800
<INTEREST-INCOME> 14,987,055
<OTHER-INCOME> 0
<EXPENSES-NET> 4,035,575
<NET-INVESTMENT-INCOME> 11,275,280
<REALIZED-GAINS-CURRENT> 15,449,627
<APPREC-INCREASE-CURRENT> (7,609,397)
<NET-CHANGE-FROM-OPS> 19,115,510
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 11,481,044
<DISTRIBUTIONS-OF-GAINS> 3,928,297
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 3,706,169
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 45,912,935
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 2,643,359
<INTEREST-EXPENSE> 1,066,000
<GROSS-EXPENSE> 326,216
<AVERAGE-NET-ASSETS> 175,081,827
<PER-SHARE-NAV-BEGIN> 39.60
<PER-SHARE-NII> 2.65
<PER-SHARE-GAIN-APPREC> 1.84
<PER-SHARE-DIVIDEND> 3.62
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 40.47
<EXPENSE-RATIO> 2.31
<AVG-DEBT-OUTSTANDING> 20,000,000
<AVG-DEBT-PER-SHARE> 4.70
</TABLE>
