CMC Materials (CCMP) DEFA14A Additional proxy soliciting materials

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES

EXCHANGE ACT OF 1934

Filed by Registrant ☑

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐	Preliminary Proxy Statement	☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)).
☐	Definitive Proxy Statement
☑	Definitive Additional Materials
☐	Soliciting Materials Pursuant to Section 240.14a-11(c) or Section 240.14a-12

CABOT MICROELECTRONICS CORPORATION
(Exact name of Registrant as Specified in Its Charter)
Payment of Filing Fee (Check the appropriate box):
	☑	No fee required.
	☐	Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.
	(1)	Title of each class of securities to which transaction applies:
	(2)	Aggregate number of securities to which transaction applies:
	(3)	Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):
	(4)	Proposed maximum aggregate value of transaction:
	(5)	Total fee paid:

*** Exercise YourRight to Vote ***

Important Notice Regarding the Availability of Proxy Materials for the

Stockholder Meeting to Be Held on March 06, 2018

	CABOT MICROELECTRONICS CORPORATION		Meeting Information Meeting Type: Annual Meeting For holders as of: January 12, 2018 Date: March 06, 2018        Time: 8:00 AM CST Location:    Cabot Microelectronics Corporation  870 N. Commons Drive  Aurora, IL 60504
			You are receiving this communication because you hold shares in the above named company. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online atwww.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting.
	CABOT MICROELECTRONICS CORPORATION ATTN: H. CAROL BERNSTEIN 870 N. COMMONS DRIVE AURORA, IL 60504
	Investor Address Line 1 Investor Address Line 2 Investor Address Line 3 Investor Address Line 4 Investor Address Line 5 John Sample 1234 ANYWHERE STREET ANY CITY, ON A1A 1A1
			See the reverse side of this notice to obtain proxy materials and voting instructions.

Broadridge Internal Use Only

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—  Before You Vote  —

How to Access the Proxy Materials

Proxy Materials Available to VIEW or RECEIVE:

1. Notice and Proxy Statement        2. Annual Report         3. Telephone/Internet insert (BR supplied)

How to View Online:

Have the information that is printed in the box marked by the arrow   (located on the following page) and visit:www.proxyvote.com.

How to Request and Receive a PAPER orE-MAIL Copy:

If you want to receive a paper ore-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request:

                               1)BY INTERNET:         www.proxyvote.com

                               2)BY TELEPHONE:     1-800-579-1639

                               3)BY E-MAIL*:             sendmaterial@proxyvote.com

*   If requesting materials bye-mail, please send a blanke-mail with the information that is printed in the box marked by the arrow   (located on the following page) in the subject line.

Requests, instructions and other inquiries sent to thise-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before February 20, 2018 to facilitate timely delivery.

—  How To Vote  —

Please Choose One of the Following Voting Methods

VoteInPerson:Many stockholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares. Vote By Internet: To vote now by Internet, go towww.proxyvote.com.Have the information that is printed in the box marked by the arrow    available and follow the instructions. VoteByMail:You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

Voting items
The Board of Directors recommends you vote FOR the following:
1.      Election of Directors            Nominees 01     Barbara A. Klein     02 David H. Li     03 William P. Noglows The Board of Directors recommends you vote FOR proposals 2 and 3. 2     Non-binding stockholder advisory approval of our named executive officer compensation. 3     Ratification of the selection of PricewaterhouseCoopers LLP as the company’s independent auditors for fiscal year 2018. NOTE: Such other business as may properly come before the meeting or any adjournment thereof.

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  Reserved for Broadridge Internal Control Information  

NAME
THE COMPANY NAME INC. - COMMON	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS A	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS B	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS C	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS D	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS E	123,456,789,012.12345
THE COMPANY NAME INC. - CLASS F	123,456,789,012.12345
THE COMPANY NAME INC. - 401 K	123,456,789,012.12345

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