Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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 *
  Doubman John R
 2. Date of Event Requiring Statement (Month/Day/Year)
10/01/2018		 3. Issuer Name and Ticker or Trading Symbol
CABOT CORP [CBT]
(Last)
(First)
(Middle)
C/O CABOT CORPORATION, TWO SEAPORT LANE, SUITE 1300		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Senior Vice President
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BOSTON, MA 02210		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 13,599 (1)
D
 
Common Stock 824.9
I
Through the Trustee for the Corporation's 401(k) Plan

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (Right to Buy)   (2) 11/13/2024 Common Stock 4,017 $ 46.03 D  
Employee Stock Option (Right to Buy)   (3) 11/11/2025 Common Stock 2,306 $ 39.54 D  
Employee Stock Option (Right to Buy)   (4) 04/06/2026 Common Stock 2,834 $ 47.23 D  
Employee Stock Option (Right to Buy)   (5) 11/10/2026 Common Stock 13,747 $ 50.46 D  
Employee Stock Option (Right to Buy)   (6) 11/09/2027 Common Stock 12,639 $ 62.24 D  
Phantom Stock   (7)   (7) Common Stock 3,096.21 $ 62.72 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Doubman John R
C/O CABOT CORPORATION
TWO SEAPORT LANE, SUITE 1300
BOSTON, MA 02210		       Senior Vice President  

Signatures

By: Kristine L. Ouimet, pursuant to a power of attorney from John R. Doubman 10/10/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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) Includes 4,686 performance based units earned on the basis of the Corporation's performance in fiscal year 2016 and 2017 (which remain subject to time-based vesting) and 8,913 units subject to time-based vesting.
(2) The option vested over a three year period as follows: 30% on November 14, 2015, 30% on November 14, 2016 and 40% on November 14, 2017.
(3) The option vests over a three year period as follows: 30% on November 12, 2016, 30% on November 12, 2017 and 40% on November 12, 2018.
(4) The option vests over a three year period as follows: 30% on April 7, 2017, 30% on April 7, 2018 and 40% on April 7, 2019.
(5) The option vests over a three year period as follows: 30% on November 11, 2017, 30% on November 11, 2018 and 40% on November 11, 2019.
(6) The option vests over a three year period as follows: 30% on November 10, 2018, 30% on November 10, 2019 and 40% on November 10, 2020
(7) Each share of phantom stock is the economic equivalent of one share of Cabot Corporation common stock. The shares of phantom stock will be settled in shares of Cabot Corporation common stock upon termination of his employment with Cabot Corporation.

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