CABOT CORP — Director's Dealing 2008

Jan 3, 2008

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CABOT CORP (CBT)
CIK: 0000016040
Period of Report: 2007-12-28

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
2007-12-31	Common Stock	P	9000	$33.47	Acquired	9679700	Indirect
2007-12-31	Common Stock	P	3200	$33.48	Acquired	9682900	Indirect
2007-12-31	Common Stock	P	3400	$33.49	Acquired	9686300	Indirect
2007-12-31	Common Stock	P	3200	$33.50	Acquired	9689500	Indirect
2007-12-31	Common Stock	P	1600	$33.51	Acquired	9691100	Indirect
2007-12-31	Common Stock	P	700	$33.52	Acquired	9691800	Indirect
2007-12-31	Common Stock	P	1400	$33.53	Acquired	9693200	Indirect
2007-12-31	Common Stock	P	600	$33.54	Acquired	9693800	Indirect
2007-12-31	Common Stock	P	1600	$33.56	Acquired	9695400	Indirect
2007-12-31	Common Stock	P	1400	$33.57	Acquired	9696800	Indirect
2007-12-31	Common Stock	P	1400	$33.58	Acquired	9698200	Indirect
2007-12-31	Common Stock	P	3300	$33.59	Acquired	9701500	Indirect
2007-12-31	Common Stock	P	3200	$33.60	Acquired	9704700	Indirect
2007-12-31	Common Stock	P	11700	$33.61	Acquired	9716400	Indirect
2007-12-31	Common Stock	P	1400	$33.62	Acquired	9717800	Indirect
2007-12-31	Common Stock	P	5200	$33.63	Acquired	9723000	Indirect
2007-12-31	Common Stock	P	600	$33.64	Acquired	9723600	Indirect
2007-12-31	Common Stock	P	7700	$33.65	Acquired	9731300	Indirect
2008-01-02	Common Stock	P	3700	$32.68	Acquired	9735000	Indirect
2008-01-02	Common Stock	P	200	$32.69	Acquired	9735200	Indirect
2008-01-02	Common Stock	P	100	$32.70	Acquired	9735300	Indirect
2008-01-02	Common Stock	P	2700	$32.73	Acquired	9738000	Indirect
2008-01-02	Common Stock	P	1200	$32.75	Acquired	9739200	Indirect
2008-01-02	Common Stock	P	200	$32.76	Acquired	9739400	Indirect
2008-01-02	Common Stock	P	500	$32.80	Acquired	9739900	Indirect
2008-01-02	Common Stock	P	100	$32.81	Acquired	9740000	Indirect
2008-01-02	Common Stock	P	2066	$32.82	Acquired	9742066	Indirect
2008-01-02	Common Stock	P	834	$32.83	Acquired	9742900	Indirect
2008-01-02	Common Stock	P	800	$32.84	Acquired	9743700	Indirect
2008-01-02	Common Stock	P	200	$32.85	Acquired	9743900	Indirect

Footnotes

F1: The entities directly acquiring the shares reported on this form are SPO Partners II, L.P. ("SPO Partners"), which bought 266,600 shares, and the Elizabeth R. & William J. Patterson Foundation ("WJPFND"), which bought 5,300 shares.

F2: Due to the purchases causing this filing and related filings today, 9,413,100 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 15,200 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.