- Statement of Changes in Beneficial Ownership (4)

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	OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5
	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(f) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* WOBBY DANIEL S	2. Issuer Name and Ticker or Trading Symbol CABOT MICROELECTRONICS CORP [ CCMP ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __ X __ Officer (give title below) _____ Other (specify below) VP, Global Sales
(Last) (First) (Middle) C/O CABOT MICROELECTRONICS CORPORATION, 870 COMMONS DRIVE	3. Date of Earliest Transaction (MM/DD/YYYY) 3/8/2012
(Street) AURORA, IL 60504 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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. Trans. Date	2A. Deemed Execution Date, if any	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	3/8/2012		M		5802	A	$34.33	39584.042	D
Common Stock	3/8/2012		S ⁽¹⁾		5802	D	$36.0366	33782.042	D
Common Stock	3/8/2012		M		8704	A	$35.42	42486.042	D
Common Stock	3/8/2012		S ⁽¹⁾		8704	D	$36.0366	33782.042	D
Common Stock	3/8/2012		M		12729	A	$21.04	46511.042	D
Common Stock	3/8/2012		S ⁽¹⁾		12729	D	$36.0366	33782.042	D
Common Stock	3/9/2012		M		52551	A	$21.04	86333.042	D
Common Stock	3/9/2012		S ⁽¹⁾		52551	D	$36.0687	33782.042	D
Common Stock	3/9/2012		M		12500	A	$33.72	46282.042	D
Common Stock	3/9/2012		S ⁽¹⁾		12500	D	$36.0687	33782.042	D

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock Options (Right to Buy)	$34.33 ⁽¹⁴⁾ ⁽¹⁵⁾	3/8/2012		M			5802	5/1/2003 ⁽²⁾	5/1/2012	Common Stock	5802 ⁽⁸⁾ ⁽¹⁴⁾	$ 0	0	D
Stock Options (Right to Buy)	$35.42 ⁽¹⁵⁾ ⁽¹⁶⁾	3/8/2012		M			8704	12/11/2003 ⁽³⁾	12/11/2012	Common Stock	8704 ⁽⁸⁾ ⁽¹⁶⁾	$ 0	0	D
Stock Options (Right to Buy)	$21.04 ⁽¹⁵⁾ ⁽¹⁷⁾	3/8/2012		M			12729	12/9/2006 ⁽⁴⁾	12/9/2015	Common Stock	12729 ⁽⁸⁾ ⁽¹⁷⁾	$ 0	52551	D
Stock Options (Right to Buy)	$21.04 ⁽¹⁵⁾ ⁽¹⁷⁾	3/9/2012		M			52551	12/9/2006 ⁽⁴⁾	12/9/2015	Common Stock	52551 ⁽⁸⁾ ⁽¹⁷⁾	$ 0	0	D
Stock Options (Right to Buy)	$33.72 ⁽¹⁵⁾ ⁽¹⁸⁾	3/9/2012		M			12500	12/11/2004 ⁽⁵⁾	12/11/2013	Common Stock	12500 ⁽⁸⁾ ⁽¹⁸⁾	$ 0	16513	D
Stock Options (Right to Buy)	$26.05 ⁽¹⁵⁾ ⁽¹⁹⁾							12/10/2005 ⁽⁶⁾	12/10/2014	Common Stock	40000 ⁽⁸⁾ ⁽¹⁹⁾		40000	D
Stock Options (Right to Buy)	$21.77 ⁽¹⁵⁾ ⁽²⁰⁾							12/1/2007 ⁽⁷⁾	12/1/2016	Common Stock	41344 ⁽⁸⁾ ⁽²⁰⁾		41344	D
Stock Options (Right to Buy)	$25.79 ⁽¹⁵⁾ ⁽²¹⁾							11/30/2008 ⁽⁹⁾	11/30/2017	Common Stock	24806 ⁽⁸⁾ ⁽²¹⁾		24806	D
Stock Options (Right to Buy)	$16 ⁽¹⁵⁾ ⁽²²⁾							12/1/2009 ⁽¹⁰⁾	12/1/2018	Common Stock	40619 ⁽⁸⁾ ⁽²²⁾		40619	D
Stock Options (Right to Buy)	$21.45 ⁽¹⁵⁾ ⁽²³⁾							12/1/2010 ⁽¹¹⁾	12/1/2019	Common Stock	27417 ⁽⁸⁾ ⁽²³⁾		27417	D
Stock Options (Right to Buy)	$28.62 ⁽¹⁵⁾ ⁽²⁴⁾							12/1/2011 ⁽¹²⁾	12/1/2020	Common Stock	27853 ⁽⁸⁾ ⁽²⁴⁾		27853	D
Stock Options (Right to Buy)	$27.94 ⁽¹⁵⁾ ⁽²⁵⁾							12/1/2012 ⁽¹³⁾	12/1/2021	Common Stock	30029 ⁽⁸⁾ ⁽²⁵⁾		30029	D

Explanation of Responses:
( 1)	Sale to cover exercise price of, and taxes related to, exercise of stock options.
( 2)	Pursuant to Second Amended and Restated Equity Incentive Plan (EIP) and Compensation Committee action 9/27/04, grant agreement amended to provide that Vesting Schedule is: 25% on 5/1/03 25% on 5/1/04 25% on 5/1/05 25% on 9/1/05
( 3)	Pursuant to Second Amended and Restated Equity Incentive Plan (EIP) and Compensation Committee action 9/27/04, grant agreement amended to provide that Vesting Schedule is: 25% on 12/11/03 25% on 12/11/04 50% on 9/1/05
( 4)	2005 Option Grant Awards Vesting Schedule: 25% on 12/9/06 25% on 12/9/07 25% on 12/9/08 25% on 12/9/09
( 5)	Pursuant to Second Amended and Restated Equity Incentive Plan (EIP) and Compensation Committee action 9/27/04, grant agreement amended to provide that Vesting Schedule is: 25% on 12/11/04 75% on 9/1/05
( 6)	Vesting Schedule: 25% 12/10/05 25% 12/10/06 25% 12/10/07 25% 12/10/08
( 7)	2006 Stock Option Grant Award Vesting Schedule: 25% 12/1/07, 25% 12/1/08, 25% 12/1/09, 25% 12/1/10
( 8)	As a result of a leveraged recapitalization of the Company via a special cash dividend (the "Dividend") of $15.00 per share declared on February 13, 2012 with a record date of February 23, 2012, a payable date of March 1, 2012 and an ex-dividend date of March 2, 2012, the option award was proportionally adjusted on March 2, 2012 to preserve its value in connection with the Dividend, as required by Section 8.6 of the EIP and approved by the Compensation Committee of the Board of Directors of the Company. The number of stock options subject to each outstanding award was increased proportionately to preserve its value as a result of the Dividend. The number of stock options was increased by a factor of 1.45068 rounded down to the nearest whole option, which is a ratio of the Official Nasdaq Closing Price of $51.92 on March 1, 2012, the day immediately before the ex-dividend date, to the Official Nasdaq Opening Price of $35.79 on March 2, 2012, the ex-dividend date. The mandatory adjustments in connection with the Dividend were exempt from Section 16(b).
( 9)	2007 Stock Option Grant Award Vesting Schedule: 25% 11/30/08, 25% 11/30/09, 25% 11/30/10, 25% 11/30/11
( 10)	2008 Stock Option Grant Award Vesting Schedule: 25% 12/1/2009, 25% 12/1/2010, 25% 12/1/2011, 25% 12/1/2012
( 11)	2009 (FY10) Non-Qualified Stock Option Grant Vesting Schedule: 25% 12/1/2010, 25% 12/1/2011, 25% 12/1/2012, 25% 12/1/2013
( 12)	2010 (FY11) Non-Qualified Stock Option Grant Vesting Schedule: 25% 12/1/2011, 25% 12/1/2012, 25% 12/1/2013, 25% 12/1/2014.
( 13)	2011 (FY12) Non-Qualified Stock Option Grant Vesting Schedule: 25% 12/1/2012, 25% 12/1/2013, 25% 12/1/2014, 25% 12/1/2015.
( 14)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 4,000 shares of common stock at an exercise price of $49.80.
( 15)	Required by Section 8.6 of the EIP and approved by the Compensation Committee of the Board of Directors of the Company, the exercise price of the option was proportionally adjusted on March 2, 2012 to preserve its value as a result of the leveraged recapitalization via the Dividend. The exercise price of each outstanding stock option was decreased by a factor of 0.68933 rounded up to the nearest whole cent, which is a ratio of the Official Nasdaq Opening Price of $35.79 on March 2, 2012, the ex-dividend date, to the Official Nasdaq Closing Price of $51.92 on March 1, 2012, the day immediately before the ex-dividend date. The mandatory adjustments in connection with the Dividend were exempt from Section 16(b).
( 16)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 6,000 shares of common stock at an exercise price of $51.37.
( 17)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 60,000 shares of common stock at an exercise price of $30.51.
( 18)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 20,000 shares of common stock at an exercise price of $48.91.
( 19)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 40,000 shares of common stock at an exercise price of $37.78.
( 20)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 28,500 shares of common stock at an exercise price of $31.57.
( 21)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 17,100 shares of common stock at an exercise price of $37.40.
( 22)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 28,000 shares of common stock at an exercise price of $23.21.
( 23)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 18,900 shares of common stock at an exercise price of $31.11.
( 24)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 19,200 shares of common stock at an exercise price of $41.51.
( 25)	This option pursuant to the EIP, was previously reported by the reporting person as an option for 20,700 shares of common stock at an exercise price of $40.52.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
WOBBY DANIEL S C/O CABOT MICROELECTRONICS CORPORATION 870 COMMONS DRIVE AURORA, IL 60504			VP, Global Sales

Signatures
/s/ H. Carol Bernstein (Power of Attorney)		3/12/2012
^** Signature of Reporting Person		Date

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