X0303 4 2011-02-04 0 0000016040 CABOT CORP CBT 0001243739 BERUBE BRIAN A C/O CABOT CORPORATION TWO SEAPORT LANE BOSTON MA 02210 0 1 0 0 Vice President,General Counsel Common Stock 2011-02-04 4 S 0 12000 43.95 D 43464 D Common Stock 10786.9115 I Through the Trustees for the Corporation's Retirement Savings Plan The price reported is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $43.88 to 44.03, inclusive. The reporting person undertakes to provide to the staff of the Securities and Exchange Commission, the Corporation or any security holder of the Corporation, upon request, full information regarding the number of shares sold at each separate price. Reflects retirement plan contributions by the Corporation, including contributions that have occurred since the date of the reporting person's last ownership report. By: Karen Abrams, pursuant to a power of attorney from Brian A. Berube 2011-02-08