X0306 4 2017-09-30 0 0000016040 CABOT CORP CBT 0001243739 BERUBE BRIAN A C/O CABOT CORPORATION TWO SEAPORT LANE, SUITE 1300 BOSTON MA 02210 0 1 0 0 SVP, General Counsel Phantom Stock 2017-09-30 4 A 0 114.7643 55.80 A Common Stock 114.7643 16252.8618 D 1 for 1 The reported phantom stock units were acquired under the Corporation's supplemental 401(k) plan and are to be settled upon the reporting person's retirement or other termination of service in accordance with the provisions of the plan. By: Kristine L. Ouimet, pursuant to a power of attorney from Brian A. Berube 2017-10-03