SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Mason Jonathan P

(Last)

(First)

(Middle)

CABOT CORPORATION

TWO SEAPORT LANE

(Street)

BOSTON

02210

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
CABOT CORP [ CBT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Executive Vice President, CFO

3. Date of Earliest Transaction (Month/Day/Year)
08/03/2007

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	08/03/2007		A		23,800⁽¹⁾	A	$13.8	49,634	D
Common Stock								1,491.5398⁽²⁾	I	Through the Trustee for the Corporation's Retirement Savings Plan.

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. Represents acquisition of shares of restricted stock awarded under Cabot's 2007 long-term incentive program. Under the terms of the award, the per share purchase price is 30% of the closing market price of Cabot common stock on May 10, 2007 ($13.80), the date the award was approved by the Compensation Committee of Cabot's Board of Directors. Mr. Mason was required to pay the purchase price for the shares by August 6, 2007. Mr. Mason paid the purchase price on August 3, 2007.

2. Prior to July 20, 2007, retirement plan contributions made by the Company under the Employee Stock Ownership Plan portion of Cabot's Retirement Savings Plan were made with shares of Series B ESOP Convertible Preferred Stock. Each share of this preferred stock was convertible into 146.3782 shares of Cabot's common stock. On July 20, 2007, all of the preferred stock held by the Trustee of the Retirement Savings Plan was converted to common stock. The amount reported here includes amounts that previously would have been reported under Table II as Series B ESOP Convertible Preferred Stock as well as retirement plan contributions made by the Company under the 401(k) portion of the Retirement Savings Plan.

Remarks:

	Michaela Allbee, pursuant to a power of attorney from Jonathan Mason	08/07/2007
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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