CABOT CORP — Director's Dealing 2007

Dec 28, 2007

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CABOT CORP (CBT)
CIK: 0000016040
Period of Report: 2007-12-26

Reporting Person: SPO ADVISORY CORP (10% Owner)
Reporting Person: SPO ADVISORY PARTNERS LP (10% Owner)
Reporting Person: SPO PARTNERS II LP (10% Owner)
Reporting Person: Elizabeth R. & William J. Patterson Foundation (10% Owner)
Reporting Person: SCULLY JOHN H (10% Owner)
Reporting Person: OBERNDORF WILLIAM E (10% Owner)
Reporting Person: PATTERSON WILLIAM J (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2007-12-27	Common Stock	P	700	$33.19	Acquired	9508000	Indirect
2007-12-27	Common Stock	P	700	$33.20	Acquired	9508700	Indirect
2007-12-27	Common Stock	P	700	$33.21	Acquired	9509400	Indirect
2007-12-27	Common Stock	P	1100	$33.22	Acquired	9510500	Indirect
2007-12-27	Common Stock	P	1300	$33.23	Acquired	9511800	Indirect
2007-12-27	Common Stock	P	700	$33.24	Acquired	9512500	Indirect
2007-12-27	Common Stock	P	1200	$33.25	Acquired	9513700	Indirect
2007-12-27	Common Stock	P	1600	$33.26	Acquired	9515300	Indirect
2007-12-27	Common Stock	P	1200	$33.27	Acquired	9516500	Indirect
2007-12-27	Common Stock	P	300	$33.28	Acquired	9516800	Indirect
2007-12-27	Common Stock	P	1000	$33.29	Acquired	9517800	Indirect
2007-12-27	Common Stock	P	1300	$33.30	Acquired	9519100	Indirect
2007-12-27	Common Stock	P	1200	$33.31	Acquired	9520300	Indirect
2007-12-27	Common Stock	P	700	$33.32	Acquired	9521000	Indirect
2007-12-27	Common Stock	P	1200	$33.33	Acquired	9522200	Indirect
2007-12-27	Common Stock	P	1000	$33.34	Acquired	9523200	Indirect
2007-12-27	Common Stock	P	900	$33.35	Acquired	9524100	Indirect
2007-12-27	Common Stock	P	1500	$33.36	Acquired	9525600	Indirect
2007-12-27	Common Stock	P	500	$33.37	Acquired	9526100	Indirect
2007-12-27	Common Stock	P	1500	$33.38	Acquired	9527600	Indirect
2007-12-27	Common Stock	P	1500	$33.39	Acquired	9529100	Indirect
2007-12-27	Common Stock	P	300	$33.40	Acquired	9529400	Indirect
2007-12-27	Common Stock	P	700	$33.41	Acquired	9530100	Indirect
2007-12-27	Common Stock	P	700	$33.42	Acquired	9530800	Indirect
2007-12-27	Common Stock	P	1100	$33.43	Acquired	9531900	Indirect
2007-12-27	Common Stock	P	800	$33.44	Acquired	9532700	Indirect
2007-12-27	Common Stock	P	1300	$33.45	Acquired	9534000	Indirect
2007-12-27	Common Stock	P	4500	$33.46	Acquired	9538500	Indirect
2007-12-27	Common Stock	P	5200	$33.47	Acquired	9543700	Indirect
2007-12-27	Common Stock	P	3800	$33.48	Acquired	9547500	Indirect

Footnotes

F1: The entities directly acquiring the shares reported on this form are SPO Partners II, L.P. ("SPO Partners"), which bought 71,400 shares, and the Elizabeth R. & William J. Patterson Foundation ("WJPFND"), which bought 1,800 shares.

F2: Due to the purchases causing this filing and related filings today, 9,146,500 shares are owned directly by SPO Partners, and may be deemed to be indirectly beneficially owned by (i) SPO Advisory Partners, L.P. ("SPO Advisory"), the sole general partner of SPO Partners, (ii) SPO Advisory Corp. ("SPO Corp."), the sole general partner of SPO Advisory, and (iii) John H. Scully ("JHS"), William E. Oberndorf ("WEO") and William J. Patterson ("WJP"), the three controlling persons of SPO Corp. 415,600 shares are owned directly by San Francisco Partners, L.P. ("SF Partners"), and may be deemed to be indirectly beneficially owned by (i) SF Advisory Partners, L.P. ("SF Advisory"), the sole general partner of SF Partners, (ii) SPO Corp., the sole general partner of SF Advisory, and (iii) JHS, WEO and WJP, the three controlling persons of SPO Corp. These shares are represented in the running total in Column 5 above, which does not include 9,900 shares held by WJPFND.

F3: Additionally, (i) 333,650 shares of the issuer's common stock may be deemed to be indirectly beneficially owned by WEO solely in his capacity as a trustee for the William and Susan Oberndorf Trust, dated 10/15/98 ("Oberndorf Trust"), (ii) 100,000 shares may be deemed to be indirectly beneficially owned by WEO solely in his capacity as general partner of Oberndorf Family Partners, a California limited partnership, (iii) WEO owns 109,000 shares in his IRA, which is self-directed, and (iv) 10,000 shares may be deemed to be indirectly beneficially owned by WEO solely in his capacity as trustee for the accounts of his two children, Peter C. Oberndorf & William Ernst Oberndorf.