Sec Form 4 Filing - Li David H @ CABOT MICROELECTRONICS CORP - 2012-03-14

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 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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1. Name and Address of Reporting Person Li David H 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, Asia Pacific Region (Last) (First) (Middle) C/O CABOT MICROELECTRONICS CORPORATION, 870 COMMONS DRIVE 3. Date of Earliest Transaction (MM/DD/YY) 03/14/2012 (Street) AURORA, IL60504 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 03/14/2012 M 5,440 A $ 35.42 21,671.3221 D Common Stock 03/14/2012 S( 1 ) 5,440 D $ 39.1372 16,231.3221 D Common Stock 03/14/2012 M 4,352 A $ 34.33 20,583.3221 D Common Stock 03/14/2012 S( 1 ) 4,352 D $ 39.1372 16,231.3221 D Common Stock 03/14/2012 M 6,745 A $ 28.62 22,976.3221 D Common Stock 03/14/2012 S( 1 ) 6,745 D $ 39.1372 16,231.3221 D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Stock Options (Right to Buy) $ 35.42 ( 9 ) ( 11 ) 03/14/2012 M 5,440 12/11/2003( 2 ) 12/11/2012 Common Stock 5,440 ( 10 ) ( 11 ) $ 0 0 D Stock Options (Right to Buy) $ 34.33 ( 9 ) ( 12 ) 03/14/2012 M 4,352 05/01/2003( 2 ) 05/01/2012 Common Stock 4,352 ( 10 ) ( 12 ) $ 0 0 D Stock Options (Right to Buy) $ 28.62 ( 9 ) ( 13 ) 03/14/2012 M 6,745 12/01/2011( 3 ) 12/01/2020 Common Stock 6,745 ( 10 ) ( 13 ) $ 0 20,237 D Stock Options (Right to Buy) $ 33.72 ( 9 ) ( 14 ) 12/11/2004( 2 ) 12/11/2013 Common Stock 2,611 ( 10 ) ( 14 ) 2,611 D Stock Options (Right to Buy) $ 26.05 ( 9 ) ( 15 ) 12/10/2005( 4 ) 12/10/2014 Common Stock 1,813 ( 10 ) ( 15 ) 1,813 D Stock Options (Right to Buy) $ 25.79 ( 9 ) ( 16 ) 11/30/2008( 5 ) 11/30/2017 Common Stock 4,206 ( 10 ) ( 16 ) 4,206 D Stock Options (Right to Buy) $ 16 ( 9 ) ( 17 ) 12/01/2009( 6 ) 12/01/2018 Common Stock 8,196 ( 10 ) ( 17 ) 8,196 D Stock Options (Right to Buy) $ 21.45 ( 9 ) ( 18 ) 12/01/2010( 7 ) 12/01/2019 Common Stock 13,491 ( 10 ) ( 18 ) 13,491 D Stock Options (Right to Buy) $ 27.94 ( 9 ) ( 19 ) 12/01/2012( 8 ) 12/01/2021 Common Stock 25,241 ( 10 ) ( 19 ) 25,241 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Li David H C/O CABOT MICROELECTRONICS CORPORATION 870 COMMONS DRIVE AURORA, IL60504 VP, Asia Pacific Region Signatures /s/ H. Carol Bernstein (Power of Attorney) 03/15/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Sale to cover exercise price of, and taxes related to, exercise of stock options. ( 2 )Stock options subject to this grant is now fully vested. ( 3 )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. ( 4 )Vesting Schedule:25% 12/10/05,25% 12/10/06,25% 12/10/07,25% 12/10/08. ( 5 )Vesting Schedule:25% 11/30/0825% 11/30/0925% 11/30/1025% 11/30/11 ( 6 )2008 Stock Option Grant Award Vesting Schedule: 25% 12/1/2009, 25% 12/1/2010, 25% 12/1/2011, 25% 12/1/2012 ( 7 )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 ( 8 )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. ( 9 )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). ( 10 )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). ( 11 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 3,750 shares of common stock at an exercise price of $51.37. ( 12 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 3,000 shares of common stock at an exercise price of $49.80. ( 13 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 18,600 shares of common stock at an exercise price of $41.51. ( 14 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 1,800 shares of common stock at an exercise price of $48.91. ( 15 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 2,500 shares of common stock at an exercise price of $37.78. ( 16 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 2,900 shares of common stock at an exercise price of $37.40. ( 17 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 22,600 shares of common stock at an exercise price of $23.21. ( 18 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 18,600 shares of common stock at an exercise price of $31.11. ( 19 )This option pursuant to the EIP, was previously reported by the reporting person as an option for 17,400 shares of common stock at an exercise price of $40.52.

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