PAGE 1 000 A000000 06/30/2008 000 C000000 0000275694 000 D000000 N 000 E000000 NF 000 F000000 Y 000 G000000 Y 000 H000000 N 000 I000000 6.1 000 J000000 U 001 A000000 MASSMUTUAL CORPORATE INVESTORS 001 B000000 811-2183 001 C000000 4132261516 002 A000000 1500 MAIN STREET, P.O. BOX 15189 002 B000000 SPRINGFIELD 002 C000000 MA 002 D010000 01115 003 000000 N 004 000000 N 005 000000 N 006 000000 N 007 A000000 N 007 B000000 0 008 A000001 BABSON CAPITAL MANAGEMENT LLC 008 B000001 A 008 C000001 801-241 008 D010001 SPRINGFIELD 008 D020001 MA 008 D030001 01115 008 D040001 5189 058 A000000 N 059 000000 Y 060 A000000 Y 060 B000000 Y 061 000000 0 062 A000000 Y 062 B000000 0.0 062 C000000 0.0 062 D000000 0.0 062 E000000 0.0 062 F000000 0.0 062 G000000 0.0 062 H000000 0.0 062 I000000 6.9 062 J000000 0.0 062 K000000 0.0 062 L000000 0.0 062 M000000 0.0 062 N000000 0.0 062 O000000 0.0 062 P000000 87.1 062 Q000000 0.0 PAGE 2 062 R000000 15.6 071 A000000 47304 071 B000000 47971 071 C000000 255259 071 D000000 19 072 A000000 6 074 N000000 278326 074 T000000 246925 075 A000000 0 075 B000000 249049 077 A000000 Y 077 Q010000 Y 077 Q020000 N 077 Q030000 Y 078 000000 N SIGNATURE JAMES M. ROY TITLE V.P. AND C.F.O.