X0303 4 2009-06-30 0001102934 CABOT MICROELECTRONICS CORP CCMP 0001223693 JOHNSON WILLIAM S C/O CABOT MICROELECTRONICS CORPORATION 870 COMMONS DRIVE AURORA IL 60504 1 Vice President, CFO Common Stock 2009-06-30 4 A 0 279.067 26.77 A 36521.287 D Common Stock 800 I Trust Represents shares held in trust for the benefit of Mrs. Johnson, as to which Mr. Johnson has no investment control. Accordingly, he is not deemed the beneficial owner of such shares for Section 16 purposes but wishes to report these shares on a voluntary basis. /s/ H. Carol Bernstein (Power of Attorney) 2009-07-01