CABOT CORP — Director's Dealing 2008

Oct 2, 2008

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CABOT CORP (CBT)
CIK: 0000016040
Period of Report: 2008-09-30

Reporting Person: CLARKESON JOHN S (Director)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2008-09-30	Phantom Stock Units	$	A	432.6621	Acquired		Common Stock (432.6621)	Direct

Footnotes

F1: 1 for 1

F2: Immediately exercisable

F3: The shares of phantom stock become payable upon the reporting person's termination of service as a director.

F4: On July 11, 2008, Cabot's Board of Directors declared a dividend of $0.18 per share on Cabot common stock, payable on September 12, 2008 to all holders of record of common stock on August 29, 2008. Mr. Clarkeson received a dividend on his phantom stock units totalling $2,297.01, which was immediately reinvested in phantom stock units at a price of $32.31 per share. As a result, 71.0929 phantom stock units were allocated to Mr. Clarkeson on September 12, 2008.