Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Prevost Patrick M.
  2. Issuer Name and Ticker or Trading Symbol
CABOT CORP [CBT]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O CABOT CORPORATION, TWO SEAPORT LANE, SUITE 1300
3. Date of Earliest Transaction (Month/Day/Year)
02/17/2017
(Street)

BOSTON, MA 02210
4. If Amendment, Date 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
(City)
(State)
(Zip)
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)
Code V Amount (A) or (D) Price
Common Stock 02/17/2017   M   40,328 A $ 55.37 (1) 293,548 D  
Common Stock 02/17/2017   D   12,139 D $ 55.37 (1) 281,409 D  
Common Stock 02/21/2017   M   92,562 A $ 34.64 373,971 D  
Common Stock 02/21/2017   S   92,562 D $ 58.22 (2) 281,409 D  
Common Stock               50.02 (3) I Through the Trustee for the Corporation's 401(k) plan

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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 Underlying Securities
(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 of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Phantom Stock (4) 02/17/2017   M   40,328   02/17/2017 02/17/2017 Common Stock 40,328 $ 0 0 D  
Employee Stock Option (Right to Buy) $ 34.64 02/21/2017   M     92,562   (5) 10/15/2019 Common Stock 92,562 $ 0 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Prevost Patrick M.
C/O CABOT CORPORATION
TWO SEAPORT LANE, SUITE 1300
BOSTON, MA 02210
  X      

Signatures

 By: Kristine L. Ouimet, pursuant to a power of attorney from Patrick M. Prevost   02/22/2017
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) The price reported is the closing price of Cabot stock as of January 31, 2017, the date the phantom stock was valued for settlement under the terms of the Supplemental 401(k) Plan.
(2) The price reported is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from 58.15 to $58.74, 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.
(3) Reflects retirement plan contributions by the Corporation.
(4) 1 for 1
(5) 92,562 shares were subject to the option. The option vested over a three year period as follows: 30% November 12, 2011, 30% November 12, 2012 and 40% on November 12, 2013.

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