Cabot to re-purchase more shares

Boston, Massachusetts -- Cabot Corp.'s board has given permission for the company to buy back a further five million of its own shares, bringing the total

number of shares authorized for repurchase to ten million. To date, the Company has repurchased

approximately 4.1 million shares.

Cabot's management said it will be in full control of the timing and amount of any purchase. As of

June 30, 2007, the Company had cash and cash equivalents of

approximately $229 million. Any shares purchased through this program

will be retired and restored to the status of authorised but unissued

shares of common stock of the Company. As of September 13, 2007, the

Company had approximately 66.6 million shares of common stock

outstanding.