CABOT MICROELECTRONICS CORPORATION

870 North Commons Drive

Aurora, Illinois 60504

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To be held March 3, 20156, 2018

To our Stockholders:

We are notifying you that the Annual Meeting2018 annual meeting of Stockholdersstockholders of Cabot Microelectronics Corporation will be held on Tuesday, March 3, 20156, 2018 at 8:00 a.m. local time at Cabot Microelectronics Corporation,our corporate headquarters located at 870 North Commons Drive, Aurora, Illinois 60504 for the following purposes:

1. To elect three directors, each for a term of three years;

2. To hold anon-binding stockholder advisory vote to approve our named executive officer compensation;

3. To ratify the selection of PricewaterhouseCoopers LLP, an independent registered public accounting firm, as our independent auditors for fiscal year 2015;2018; and

4. To transact other business properly coming before the meeting.

Each of these matters is described in further detail in the accompanying proxy statement. We also have included a copy of our 20142017 Annual Report. Only stockholders of record at the close of business on January 9, 201512, 2018 are entitled to vote at the meeting or any postponements or adjournments of the meeting. A complete list of these stockholders will be available at our principal executive offices prior to the meeting.

We are delivering our proxy statement and 20142017 Annual Report under the United States Securities and Exchange Commission rules that allow companies to furnish proxy materials to their stockholders over the internet. Accordingly, we are sending a Notice of Internet Availability of Proxy Materials to our stockholders, which is designed to reduce our printing and mailing costs and the environmental impact of the proxy materials.materials and our 2017 Annual Report (collectively, the “Proxy Materials”). A paper copy of our proxy materialsProxy Materials may be requested through one of the methods described in the Notice of Internet Availability of Proxy Materials.

Please use this opportunity to take part in our affairs by voting your shares. You are cordially invited to attend the meeting in person. If you wish to attend the meeting in person, please bring a valid form of photo identification to the meeting. If your stock is not registered in your own name and you plan to attend the meeting and vote in person, you should contact your broker or agent in whose name your stock is registered to obtain a broker’s proxy and bring it to the meeting in order to vote at the meeting.

Whether or not you plan to attend the meeting, your vote is important.Please promptly submit your proxy by telephone, internet or mail by following the instructions found on your Notice of Internet Availability of Proxy Materials or proxy card. Your proxy can be withdrawn by you at any time before it is voted.

By order of the Board of Directors,

William P. Noglows

Chairman of the Board

Aurora, Illinois

This proxy statement is dated January 20, 2015,23, 2018, and is first being made available to stockholders electronically via the internet on or about January 20, 2015.23, 2018.

Table Of Contents

CABOT MICROELECTRONICS CORPORATION

870 North Commons Drive

Aurora, Illinois 60504

PROXY STATEMENT

The Board of Directors of Cabot Microelectronics Corporation is asking for your proxy for use at the annual meeting of our stockholders to be held on Tuesday, March 3, 20156, 2018 at 8:00 a.m. local time, at Cabot Microelectronics Corporation,our corporate headquarters located at 870 North Commons Drive, Aurora, Illinois 60504 and at any postponements or adjournments of the meeting.

PursuantIn accordance with and pursuant to the rules and regulations adopted by the United States Securities and Exchange Commission (“SEC”), we are providing our stockholders with access to our proxy materialsProxy Materials over the internet rather than in paper form. Accordingly, we are sending a Notice of Internet Availability of Proxy Materials, rather than a printed copy of the proxy materials,Proxy Materials, to our stockholders of record as of January 9, 2015.12, 2018. We expect to mail the Notice of Internet Availability of Proxy Materials to stockholders entitled to vote at our annual meeting on or about January 20, 2015.23, 2018.

ABOUT THE MEETING

What is the purpose of the annual meeting?

At our annual meeting, stockholders will act upon the matters outlined in the accompanying notice of meeting, including the election of three directors, the non-binding stockholder advisory vote to approve our named executive officer compensation and the ratification of the selection of our independent auditors. including:

In addition, our management will report generally on the fiscal year ended September 30, 20142017 and respond to questions from stockholders.

What is the Notice of Internet Availability of Proxy Materials?

On or about January 20, 2015, we will mail to our stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access and review our proxy materials and our 2014 annual report. The Notice of Internet Availability of Proxy Materials will instruct you as to how you may access and review the proxy materialsProxy Materials and submit your proxy via the internet or phone. If you would like to receive a printed copy of the proxy materials,Proxy Materials, please follow the instructions included in the Notice of Internet Availability of Proxy Materials for requesting printed materials.

Important Notice Regarding the Availability of Proxy Materials for the Stockholder Meeting to Be Held March 3, 2015:6, 2018:

What are our voting recommendations?How does the board recommend I vote?

Our board of directors unanimously recommends that you vote your shares “FOR” the election of each of the nominees named below under “ELECTION OF DIRECTORS”, “FOR” non-binding advisory approval of our named executive officer compensation and “FOR” the ratification of the selection of our independent auditors.

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Who is entitled to vote?

Only stockholders of record at the close of business on the record date, January 9, 2015,12, 2018, are entitled to receive notice ofand vote at the annual meeting and to vote the shares of common stock that they held on that date at the meeting, or any postponements or adjournments of the meeting. Each outstanding share of common stock entitles its holder to cast one vote, without cumulation, on each matter to be voted on. As of the record date, we had approximately 25,540,950 shares of common stock outstanding and entitled to vote.

What is the difference between holding shares as a record holder and as a beneficial owner?

Record Holder.    You are a record holder of our common stock if at the close of business on the record date your shares were registered directly in your name with Computershare Trust Company, N.A., P.O. Box 43078, Providence, Rhode Island 02940-3078, our stock transfer agent.

Beneficial Owner.    You are a beneficial owner if at the close of business on the record date your shares were held by a broker, bank, custodian, nominee or other record holder of our common stock and not in your name. Being a beneficial owner means that, like most of our stockholders, your shares are held in “street name.” As the beneficial owner, you have the right to direct your broker or nominee how to vote your shares by following the voting instructions your broker or other nominee provides. If you do not provide your broker or nominee with instructions on how to vote your shares, your broker or nominee will be able to vote your shares with respect to some of the proposals, but not all. Please see “What if I did not specify how my shares are to be voted?” for additional information.

What constitutes a quorum?

If a majority of the shares outstanding on the record date are present at the annual meeting, either in person or by proxy, we will have a quorum at the meeting permitting the conduct of business at the meeting. As of the record date, we had approximately 24,086,48925,540,950 shares of common stock outstanding and entitled to vote. Any shares represented by proxies that are marked to abstain from voting on a proposal will be counted as present for purposes of determining whether we have a quorum. If a broker, bank, custodian, nominee or other record holder of our common stock indicates on a proxy that it does not have discretionary authority to vote certain shares on a particular matter, the shares held by that record holder (referred to as “brokernon-votes”) will also be counted as present in determining whether we have a quorum.

How do I vote, and can I vote by telephone or through the internet?

You may vote in person at the annual meeting or you may vote by proxy. If your stock is registered in your own name, you may vote in person by attending the meeting, presenting a valid form of photo identification and delivering your completed proxy card in person. If your stock is not registered in your own name and you plan to attend the meeting and vote in person, you should contact your broker or agent in whose name your stock is registered to obtain a broker’s proxy and bring it to the meeting along with a valid form of photo identification. You may vote by proxy by signing, dating and mailing a proxy card. In addition, you may vote by telephone or through the internet by following the instructions below or those included in the Notice of Internet Availability of Proxy Materials.

To vote by telephone, if you are a record holder of our common stock, call toll free1-800-690-6903 and follow the instructions provided by the recorded message. To vote by telephone if you are a beneficial owner of our common stock, call the toll free number listed in the Proxy Cardproxy card or follow the instructions provided by your broker. For all holders of our common stock (whether record or beneficial), to vote through the internet, go towww.proxyvote.com and follow the steps on the secure website. You also may access the proxyvote website (www.proxyvote.com) or view our proxy materialsProxy Materials by going to our website,www.cabotcmp.com, selecting “Investor Relations” on our Homepage, and then selecting “Annual Meeting/Proxy” from the drop down menu.

If you vote by proxy, the individuals named on the proxy card as proxy holders will vote your shares in the manner you indicate.

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What if I do not specify how my shares are to be voted?

Record Holder.    If you are a record holder of our common stock and you sign and return the proxy card without indicating your instructions, your shares will be voted “FOR”“FOR”:

Beneficial Owners.    If you are a beneficial owner and you do not provide the broker, bank, custodian, nominee or other record holder that holds your shares with voting instructions, such person will determine if it has the discretionary authority to vote on the particular matter. Under applicable rules, such person has the discretion to vote on routine matters such as the ratification of our independent auditors, but does not have discretion to vote onnon-routine matters such as the election of directorsa director, and thenon-binding stockholder advisory vote to approve our named executive officer compensation.

Can I revoke my proxy or change my vote after I return my proxy card or after I vote electronically via the internet or by telephone?

Yes. Even after you have submitted your proxy, you may revoke your proxy or change your vote at any time before the proxy is voted at the annual meeting by delivering to our Secretary a written notice of revocation or a properly signed proxy bearing a later date, or by attending the annual meeting and voting in person. (Attendance at the meeting will not cause your previously granted proxy to be revoked unless you specifically so request.) To revoke a proxy previously submitted electronically through the internet or by telephone, you may simply vote again at a later date, using the same procedures, in which case the later submitted vote will be recorded and the earlier vote revoked.

What vote is required to approve each matter that comes before the meeting?

Our bylaws provide that director nominees must receive the affirmative vote of a plurality of the votes cast at the meeting by stockholders entitled to vote thereon, meaning that the three nominees for director with the most votes will be elected. However, our Corporate Governance Guidelines, which are available through our website,www.cabotcmp.com, provide that in an uncontested election, any nominee for director who receives a greaterThe number of votes “withheld” from his or her election than votes “for” such election (a “Majority Withheld Vote”) shall promptly tender his or her resignation following certificationrequired to approve each of the stockholder vote for such election. In this situation, our nominating and corporate governance committee then shall consider the resignation offer and recommend to our board of directors whether to accept it. The board of directors then will act on the nominating and corporate governance committee’s recommendation within ninety (90) days following certification of the stockholder vote for such election. Thereafter, the board of directors will promptly disclose its decision whether to accept the director’s resignation offer (and the reasons for rejecting the resignation offer, if applicable), in a press releaseproposals scheduled to be disseminated in the manner that we typically distribute press releases.

The non-binding stockholder advisory vote to approve our named executive officer compensation requires the affirmative vote of a majority of the votes castpresented at the meeting in person or by proxy by stockholders entitled to vote thereon. If the named executive officer compensation is not approved, then our compensation committee and our board of directors will meet following the annual meeting to consider the results of such non-binding stockholder advisory vote.

The ratification of the selection of our independent auditors requires the affirmative vote of a majority of the votes cast at the meeting in person or by proxy by stockholders entitled to vote thereon. If our independent auditors are not ratified, then our audit committee and our board of directors will meet following the annual meeting to the consider the results of such non-binding ratification vote.

as follows. Abstentions and brokernon-votes will not be counted for purposes of determining whether an item has received the requisite number of votes for approval.

Proposal				Required Vote
1.   Election of Directors				For each nominee, a plurality of the votes cast are “FOR” such nominee (i.e., the nominees for director with the most votes will be elected).*
2.   Advisory vote to approve named executive officer compensation				A majority of the votes cast are “FOR” the proposal.
3.   Ratification of the selection of our independent auditors				A majority of the votes cast are “FOR” the ratification.

What happens if additional proposals are presented at the meeting?

Other than the matters described in this proxy statement, we do not expect any additional matters to be presented for a vote at the annual meeting. If you vote by proxy, your proxy grants the persons named as proxy holders the discretion to vote your shares on any additional matters properly presented for a vote at the meeting.

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Who will bear the costs of soliciting votes for the meeting?

We will bear all costs of solicitation. Certain directors, officers and employees, who will not receive any additional compensation for such activities, may solicit proxies by personal interview, mail, telephone or electronic communication. We will also reimburse brokerage houses and other custodians, nominees and fiduciaries for their reasonableout-of-pocket expenses for forwarding proxy and solicitation materials to our stockholders. In addition to the mailing of these proxy materials,Proxy Materials, we have hired the firm of D.F. King & Co., Inc. to assist in the solicitation of proxies at an estimated cost of approximately $8,000. We shall bear$9,000.

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CABOT MICROELECTRONICS CORPORATION

2018 PROXY STATEMENT – SUMMARY

This summary highlights information contained elsewhere in the proxy statement. This summary does not contain all costs of solicitation.

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STOCK OWNERSHIP

Security Ownership of Certain Beneficial Owners and Management

The following table sets forth certain information regarding the beneficial ownership of our common stock as of January 9, 201512, 2018 (except as indicated below) by:

Unless otherwise indicated, each stockholder listed below has sole voting and investment power with respect to the shares of common stock beneficially owned by such stockholder.

Stock Ownership Table

Name and Address		Number of  Shares Beneficially Owned(1)				Approximate Percent of  Class(1)
Bailing Xia			87,795	(8)			*
William S. Johnson			264,863	(8)			1.1	%
Adam F. Weisman			160,223	(8)(9)			*
Ananth Naman			39,257	(8)			*
All directors and executive officers as a group (19 persons)			2,115,454	(10)			8.8	%

Name and Address		Number of  Shares Beneficially           Owned1				Approximate Percent of Class1
Certain beneficial owners:
1. BlackRock, Inc.     55 East 52nd Street     New York, New York 10022			3,324,018	2			13.0%
2. The Vanguard Group, Inc.     P.O. Box 2600     Valley Forge, Pennsylvania 19482			2,377,639	3			9.3%
3. JPMorgan Chase & Co.     270 Park Avenue     New York, New York 10017			1,793,497	4			7.0%
Directors and executive officers:
David H. Li			125,092	5			*
William P. Noglows			170,078	5 6			*
Richard S. Hill			13,915	5			*
Barbara A. Klein			91,849	5			*
Paul J. Reilly			7,515	5
Susan M. Whitney			34,178	5			*
Geoffrey Wild			34,178	5			*
William S. Johnson8			129,593	5			*
H. Carol Bernstein			72,837	5			*
Ananth Naman			35,309	5			*
Daniel D. Woodland			20,925	5			*
All directors and executive officers as a group (15 persons)			836,618	8			3.3%

*	= less than 1%

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(7)3

Of the shares reported as beneficially owned, The Vanguard Group, Inc. exercises (a) sole power to vote 34,41448,342 shares, (b) shared power to vote 03,700 shares, (c) no power to vote 1,464,3612,325,597 shares, (d) sole investment power over 1,465,8612,327,197 shares, and (e) shared investment power over 32,91450,442 shares. The total number of shares reported as beneficially owned is 1,498,775.2,377,639, as of September 30, 2017. The number of shares indicated is based on information reported in the Form 13F Holdings Report filed by The Vanguard Group, Inc. on November 12, 2014.14, 2017.

Also includes restricted shares of common stock awarded to such executive officer pursuant to the 2000 Equity2012 Omnibus Incentive Plan on December 1, 2011,3, 2014 and January 2, 2015, and restricted stock units awarded to such executive officer pursuant to the 2012 Omnibus Incentive Plan on December 3, 2012,2015, December 3, 20135, 2016 and December 3, 2014,5, 2017, respectively, that are still subject to restrictions as of January 9, 2015,12, 2018, as set forth in the table below. On December 1, 2011, December 3, 2012, December 3, 2013 and December 3, 2014, as part of our annual equity incentive award program, we awarded restricted shares to our executive officers with restrictions that lapse in equal increments upon each anniversary over four years exceptand that pursuantmay not be sold or transferred, other than to his Executive Chairman employment letter, all unvestedimmediate family members as provided in the 2012 Omnibus Incentive Plan. On December 3, 2015, December 5, 2016 and December 5, 2017, as part of our annual equity incentive award program, we awarded restricted stock held by Mr. Noglows will vestunits

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to our executive officers with restrictions that lapse in full (1) at end of the employment term, subject to Mr. Noglows’ continued employment through the end of the employment term, or (2)equal increments upon the earlier termination of Mr. Noglows’ employment by us without cause or by Mr. Noglows due to a material breach by us of the employment letter subject to Mr. Noglows’ execution and non-revocation of a release of claims against us.each anniversary over four years. On January 2, 2015, as part of Mr. Li’s appointment as our President and Chief Executive Officer, we awarded 14,700 restricted shares to Mr. Li with restrictions that lapse in equal increments upon each anniversary of the award over four years. On January 2, 2015, related to thethis leadership transition, we awarded 22,222 restricted shares to Mr. Johnson with restrictions that lapse in equal increments upon each anniversary of the award over four years. The outstanding restricted stock awards are eligible to receive dividends and have voting rights.

		Equity Incentive Program Restricted Shares
Name		12/01/11				12/03/12				12/03/13				12/03/14				1/02/15
Mr. Noglows			5,500				12,500				18,750				44,400				—
Mr. Li			1,450				3,000				4,425				5,200				14,700
Mr. Johnson			2,175				4,900				6,375				7,100				22,222
Mr. Weisman			1,725				3,950				5,400				5,800				—
Dr. Naman			1,375				3,250				4,950				6,100				—

Also includes both The outstanding restricted stock unit awards have the same economic value as shares of common stock, that such executive officer has purchased at fair market valueare eligible to receive dividend equivalents, and may not be voted, sold or transferred, other than to immediate family members as “deposit shares” and for which the executive officer has been awarded a matching grant of “award shares”, pursuant to our Executive Officer Deposit Share Program, that are still subject to restrictions (with respect to “award shares”) or conditions (with respect to “deposit shares”) as of January 9, 2015 as set forthprovided in the table below. Under this program, our executive officers are entitled to voluntarily use all or a portion of their after-tax annual cash bonus compensation to purchase at fair market value shares of restricted stock awarded under the 2012 Omnibus Incentive Plan, and before that, under the 2000 Equity Incentive Plan. These shares are retained on deposit with us until the third anniversary of the date of deposit (“deposit shares”), and our company matches the deposit with a restricted stock award equal to 50% of the shares deposited by the participant (“award shares”). If the participant is employed by our company on the third anniversary of the deposit date and the deposit shares have remained on deposit with us through such date, the restrictions on the award shares will lapse. Such executive officer has dividend and voting rights with respect to the restricted shares.

Also includes restricted stock units awarded to suchnon-employee director pursuant to the 2012 Omnibus Incentive Plan that are still subject to restrictions as of January 9, 2015,12, 2018, as set forth in the table below. For annual equity awards tonon-employee directors, restricted stock units are currently awarded with restrictions that lapse in full upon the first anniversary of the award. Initial equity awards of restricted stock units tonon-employee directors are currently made with restrictions that lapse in equal annual increments over four years beginning on the datefirst anniversary of the award, as with awards to our employees, including our executive officers. Outstanding restricted stock awards are eligible to receive dividends and have voting rights but may not be sold or transferred, other than to immediate family members as provided in the plan.award. Outstanding restricted stock unit awards have the same economic value as shares of common stock, but do notare eligible to receive dividendsdividend equivalents, and may not be voted, sold or transferred, other than to immediate family members as provided in the plan.

Name		Non-Employee Director Restricted Stock Units
Mr. BirgeneauNoglows			2,000
Mr. Frazee			2,000
Mr. Fuller			2,000	1,352
Mr. Hill			2,625	1,352
Ms. Klein			2,000	1,352
Mr. MooneyReilly		2,704
2,000 Ms. Whitney		1,977
Mr. WilkinsonWild			2,000
Mr. Xia			2,000

Also includes phantom shares of our common stock that such non-employee director has the right to acquire pursuant to the Directors’ Deferred Compensation Plan as of January 9, 2015, as follows:

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Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the Securities Exchange Act of 1934 requires our directors, executive officers and holders of more than 10% of our common stock to file with the Securities and Exchange CommissionSEC reports regarding

their ownership and changes in ownership of our common stock. Based solely on our review of the reports furnished to us, we believe that all of our directors and executive officers have complied with all Section 16(a) filing requirements for fiscal year 2014.2017.

ELECTION OF DIRECTORS

Our board of directors is currently comprised of tenseven directors. The board of directors is divided into three classes: Class I, whose terms will expire at the annual meeting of stockholders to be held in 2016;2019; Class II, whose terms will expire at the annual meeting of stockholders to be held in 2017;2020; and Class III, whose terms will expire at the upcoming annual meeting of stockholders. Messrs. Fuller,Mr. Hill and MooneyMs. Whitney are currently in Class I, Messrs. Birgeneau, WilkinsonWild and XiaReilly are currently in Class II, and Messrs. Frazee, Li and Noglows, and Ms. Klein are currently in Class III. Mr. Frazee has decided not to stand for re-election when his term expires at the upcoming annual meeting of stockholders, and therefore will cease to be a member of the board of directors as of such time. At such time, the board of directors will be comprised of nine directors, with three directors in Class III.

At each annual meeting of stockholders, directors for the successors to directors whose terms will then expireclass of which term expires at the annual meeting will be elected to serve from the time of election and qualification until the third annual meeting following election. Our certificate of incorporation provides that the authorized number of directors may be changed only by resolution of the board of directors, and that the board of directors may increase or decrease the authorized number of directors. Any additional directorships resulting from an increase in the number of directors will be distributed among the three classes so that, as nearly as possible, each class will consist ofone-third of the total number of directors. Our certificate of incorporation also provides that our board of directors may fill any vacancy created by the resignation of a director or the increase in the size of our board of directors.

The board of directors has nominated and urges you to vote “FOR”“FOR” the election of the three nominees named below for termsa term of office ending in 2018.2021.

In the event a nominee isthe nominees are not available to serve for any reason when the election occurs, it is intended that the proxies will be voted for the election of the other nominees and may be voted for any substitute nominee.nominees. Our board of directors has no reason to believe that any of the nominees will not be a candidatecandidates or, if elected, will be unable or unwilling to serve as a director.directors. In no event will the proxies be voted for a greater number of persons than the number of nominees named.

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Our board of directors unanimously recommends that you vote “FOR” the election to the board of each of the nominees named below.

Nominees for Director for termsa term that expireexpires in 2018:2021:

Barbara A. Klein, 60, was elected a director of our company in April 2008. Ms. Klein also is a director of Ingredion, Inc. She retired in May 2008 as the Senior Vice President and Chief Financial Officer of CDW Corporation. Prior to that, Ms. Klein held a variety of senior finance positions including Vice President and Chief Financial Officer of Dean Foods Company, Vice President and Corporate Controller of Ameritech Corporation, and Vice President and Corporate Controller of Pillsbury Co. She is a certified public accountant. Ms. Klein received a B.S. in accounting and finance from Marquette University, and a M.B.A. from Loyola University. Based upon Ms. Klein’s management and director experience and her accounting and finance background discussed above, the board has concluded Ms. Klein should serve as a director of our company.

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from Northwestern University. Based upon Mr. Li’s management experience, his knowledge of our company, its operations and customers, his knowledge of the chemical and semiconductor industries, and his Asia-focused, cross-border business experience, the board has concluded Mr. Li should serve as a director of our company.

William P. Noglows, 56, has served as our Chairman since 2003 and our President and Chief Executive Officer from November 2003 through December 2014. Mr. Noglows also is a director of Aspen Aerogels, Inc. and Littlefuse, Inc. From 1984 through 2003, he served in various management positions at Cabot Corporation, culminating in serving as an executive vice president and general manager. While there, he was one of the primary founders of our company and was responsible for identifying and encouraging the development of the CMP application, which is the core of our business. Mr. Noglows had previously served as a director of our company from December 1999 until April 2002. Mr. Noglows received his B.S. in chemical engineering from the Georgia Institute of Technology. Based upon Mr. Noglows’ management experience, his knowledge of our company and its operations, and his knowledge of the chemical and semiconductor industries, the board has concluded Mr. Noglows should serve as a director of our company.

Directors whose terms continue until 2016:2019:

H. Laurance Fuller, 76, was elected a director of our company in June 2002. Mr. Fuller retired from the position of Co-Chairman of BP Amoco, p.l.c. in 2000 after serving as Chairman and Chief Executive Officer of Amoco Corporation since 1991 and President since 1983. He also has served as director of various entities including Abbott Laboratories, J.P. Morgan Chase, Motorola, Inc. and Security Capital Group Incorporated. Mr. Fuller received his B.S. in chemical engineering from Cornell University. Based upon Mr. Fuller’s management and director experience and his technical background discussed above, the board has concluded Mr. Fuller should serve as a director of our company.

Richard S. Hill, 63, was elected a director of our company in June 2012. Mr. Hill retired as the Chairman and Chief Executive Officer of Novellus Systems, Inc. in June 2012 after serving in these positions since 1996, and since 1993 as CEO upon his joining Novellus. Prior to leading Novellus, Mr. Hill held various senior leadership and management positions with Tektronix, Inc., General Electric, Inc., Motorola, Inc., and Hughes Aircraft, Inc. Mr. Hill also serves as a director of Arrow Electronics, Inc., Planar Systems, Inc., and Tessera Technologies, Inc. He received a B.S. in bioengineering from the University of Illinois and a M.B.A. from Syracuse University. Based upon Mr. Hill’s management and director experience and his technical background discussed above, the board has concluded Mr. Hill should serve as a director of our company.

Edward J. Mooney, 73, was elected a director of our company in March 2005. He also serves as a director of FMC Technologies, Inc. and the Northern Trust Corporation, and has served on the boards of Commonwealth Edison, Inc., FMC Corporation and PolyOne Corporation. Mr. Mooney was the Delegue General-North America, Suez Lyonnaise des Eaux from March 2000 until his retirement in March 2001. From 1994 to 2000, he was Chairman and Chief Executive Officer of Nalco Chemical Company. Mr. Mooney received both a B.S. in chemical engineering and a J.D. from the University of Texas. Based upon Mr. Mooney’s management and director experience and his knowledge of the chemical industry discussed above, the board has concluded Mr. Mooney should serve as a director of our company.

Directors whose terms continue until 2017:2020:

Robert J. Birgeneau, 72, was elected a director of our company in March 2005. In June, 2014, he concluded his service as the Chancellor of the University of California, Berkeley, a position he had held since September 2004. He holds a faculty appointment in the departments of physics and materials science and engineering there. From July 2000 until assuming his position at Berkeley, Mr. Birgeneau served as the President of the University of Toronto. Prior to that, Mr. Birgeneau was the Dean of the School of Science at the Massachusetts Institute of Technology, and previously had been the chair of its physics department. Mr. Birgeneau received his B.S. in mathematics from the University of Toronto and his Ph.D. in physics from Yale University. Based upon Mr. Birgeneau’s management experience and his science and technology background discussed above, the board has concluded Mr. Birgeneau should serve as a director of our company.

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BOARD STRUCTURE AND COMPENSATION

Board of Directors and Board Committees

Board Leadership

Our independent directors hold regularly scheduled meetings in executive session, at which only independent directors are present. As provided in our Corporate Governance Guidelines, the Chairman of the nominating and governance committee, Mr. Hill, serves as chairman of the meetings of the independent directors in executive session and performs other responsibilities of a lead director such as working with the Chairman of the board of directors to plan and set the agenda for meetings of the board of directors. Mr. Noglows is theOurnon-executive Chairman of the board of directors and prior to January 1, 2015, also was the President and Chief Executive Officer of our company. Effective January 1, 2015, Mr. Li became our President and Chief Executive Officer, and Mr. Noglows continued as Chairman of the Board in an Executive capacity through December 2016. Thus, from and after January 1, 2015, our company has had a separate Chairman of the Board of directors (Mr. Noglows) and a separate President and Chief Executive Officer (Mr. Li), an approach that our board believes has provided a smooth leadership transition and structure for our company.

Board’s Role in Risk Oversight

The board of directors has an oversight role, as a standingwhole and at the committee level, in overseeing management of our risks. Our board focuses on our general risk management strategy, the most significant risks facing us, and oversees the implementation of risk mitigation strategies by management. The board regularly reviews information regarding our credit, liquidity, and operations, as well as risks associated with each. The compensation committee of the board is responsible for overseeing the management of risks relating to our employee compensation plans, policies, and programs, as well as our annual report on executive compensation for inclusion in each proxy statement. The audit committee a standing compensation committee and a standingof the board oversees the management of financial risks. The nominating and corporate governance committee to assistof the board is responsible for overseeing the management of directorsrisks related to corporate governance matters. While each committee is responsible for evaluating certain risks and overseeing management of such risks, the entire board is regularly informed through the committees about such risks, and reviews and discusses them in the dischargecontext of its responsibilities. our overall risk posture and risk management and mitigation strategies.

Corporate Governance

Our board of directors has adopted the Cabot Microelectronics Corporation Corporate Governance Guidelines, which are available on our website,www.cabotcmp.com, along with other corporate governance materials, such as board of directorsdirectors’ committee charters and our Code of Business Conduct. Pursuant to the Corporate Governance Guidelines, committee charters and other corporate governance materials and practices, our board of directors and committees, particularly the audit committee, periodically review and provide oversight of the management of various risk factors that are relevant to our company. Our board of directors also reviews annually the functioning of the board. During fiscal year 2014, our board of directors held 16 meetings

Shareholder Engagement and did not take action by written consent. EachCommunications with Directors

Our company values the perspectives of our directors attended at least 75%shareholders, and has a variety of all the meetings of the board and those committees onmeans by which he or she served during fiscal year 2014. With respect to our annual meeting ofwe engage with them. Also, stockholders in fiscal year 2014, all of our directors attended. Since the end of fiscal year 2014, the board of directors has met seven times and took action by written consent twice. Stockholders and third parties may communicate with our board of directors, thenon-employee directors or any individual director (including any committee chair) through the Chairman of the Board, c/o the Secretary of our company, at our offices at 870 North Commons Drive, Aurora, Illinois 60504. Depending on the nature of the communication and to whom it is directed, the Secretary of our company will: (a) forward any communication to the appropriate director or directors; (b) forward the communication to the relevant department within the company; or (c) attempt to handle the matter directly (for example, a communication dealing with a share ownership matter).

		2018 Proxy Statement    12

Independent Directors and Leadership Structure.

The board of directors has determined that sevenfive of our nineseven current directors, (Mr. Frazee will cease to be a member of the board of directors following the upcoming annual meeting of stockholders and the size of the board will be reduced accordingly to nine directors), including Messrs. Birgeneau, Fuller, Hill, Mooney, Wilkinson,Reilly and XiaWild, and Ms. Klein and Ms. Whitney, are “independent” directors as defined in Rule 4200 of the National Association of Securities Dealers Automated Quotation (“NASDAQ”) Marketplace Rules and as defined in applicable rules by the SEC. In making its determinations of independence, in addition to consideration of the relevant SEC and NASDAQ rules (according to which the definition of “independent director” is set forth in our Corporate Governance Guidelines)Guidelines, a current copy of which is available on our website,www.cabotcmp.com), the board of directors considered factors for each director such as any other directorships, any employment or consulting arrangements, and any relationship with our company’s customers, suppliers or advisors.

Board Refreshment and Succession Planning

Our independentboard of directors hold regularly scheduled meetings in executive session, at which only independent directors are present. As provided in our Corporate Governance Guidelines, the Chairmanreviews its own composition, and considers and plans for an orderly transition of the nominatingboard, including with respect to planning for potential retirements and governance committee serveswith respect to identifying potential candidates for service as

chairman new directors. As part of the meetings of the independent directors in executive session and performs other responsibilities of a lead director such as working with the Chairman ofthis process, the board of directors routinely evaluates the need for board refreshment and focuses on identifying individuals whose skills and experiences will enable them to plan and setmake meaningful contributions to the agenda for meetingsshaping of the boardfuture of directors. Following the upcoming annual meeting of stockholders, our board of directors will appoint committees and chairmanships, pursuant to its usual practice, and our board of directors will appoint another independent director to replace Mr. Frazee as the Chairman of the nominating and governance committee, and such Chairman will serve as chairman of the meetings of the independent directors in executive session. Mr. Noglows is the Chairman of the board of directors and prior to January 1, 2015, also was the President and Chief Executive Officer of our company. The board of directors believedbelieves it has made considerable strides towards these goals over the past three years.Underscoring these refreshment efforts, the board of directors has refreshed approximately 73% of its directors since 2015.Mr. Li joined the board of directorsin January 2015 in connection with his appointment as the company’s president and chief executive officer. The company also recently added three new independent directors, Ms. Whitney in April 2015, Mr. Wild in September 2015, and Mr. Reilly in March 2017. The board of directors believes all of these individuals have the relevant experience and expertise to complement that this leadership structure was appropriate at the time for our company given the size and scope of our business,other directors, and to further contribute to the experience and active involvementboard’s ongoing guidance of our independent directors, andcompany; since 2015, the board has transitioned through the retirement of six long-serving directors. Over time, our corporate governance practices, which include regular communication with and interaction between and among Mr. Noglows and the independent directors. The board believed that this approach served to provide for the board’s role in corporate governance and guiding corporate policy in an efficient manner. Effective January 1, 2015, Mr. Li became our President and Chief Executive Officer, and Mr. Noglows has continued as Chairman of the Board. Thus, from and after January 1, 2015, our company has a separate Chairman of the Board of directors (Mr. Noglows)expects to continue to focus on board refreshment and a separate Presidentthis transition process to inject relevant expertise, new skill sets, and Chief Executive Officer (Mr. Li), an approach that our board believes is appropriate while Mr. Noglows as Chairmandiverse perspectives.

Board and Mr. Li as Chief Executive Officer work to ensure a smooth leadership transition for our company. Stockholders and third parties may communicate with our independent directors through the Chairman of the nominating and corporate governance committee, c/o the Secretary of our company at our offices at 870 North Commons Drive, Aurora, Illinois 60504. Committee Meeting Attendance

During fiscal year 2014,2017, our board of directors held six meetings and took action by written consent once. Each of our directors attended at least 75% of all the meetings of the board and those committees on which he or she served during fiscal year 2017, and all directors attended our annual meeting of stockholders in fiscal year 2017. Since the end of fiscal year 2017, the board of directors has met four times and has taken action by written consent twice. During fiscal year 2017, our independent directors met in executive session tensix times. Since fiscal year end, our independent directors have met in executive session sixthree times.

Committees of the Board

The board has three standing committees: the audit committee, the compensation committee and the nominating and corporate governance committee. The following chart sets forth the directors who currently serve as members of each of the board committees.

“C” denotes member and chairman of committee

“X” denotes member of committee

		2018 Proxy Statement    13

Audit Committee.

The members of the audit committee are currently Messrs. Hill and Reilly, Ms. Klein (Chair) and Ms. Whitney. The board has determined that each of these audit committee members during fiscal year 2017 and currently are independent as defined by NASDAQ Marketplace Rules and under the applicable rules adopted by the SEC and that all such members are financially literate.

The functions of the audit committee include include:

reviewing the adequacy of our internal control procedures, including the internal audit function. The members of the audit committee are currently Messrs. Frazee, Hill and Wilkinson and Ms. Klein (Chair); Mr. Frazee will cease to be a member when he ceases to be a director as of the upcoming annual meeting. Each of these audit committee members during fiscal year 2014 and currently:

is an “independent” director as defined in Rule 4200(a)(15) of the NASDAQ Marketplace Rules;

meets the criteria for independence as required by applicable rules adopted by the SEC;

has not participated in the preparation of our financial statements or the financial statements of any of our current subsidiaries at any time during the past three years; and

is able to read and understand fundamental financial statements.

Our board of directors has determined that the audit committee has at least one member who qualifies as an Audit Committee Financial Expert, as defined by relevant SEC rules, and has designated Ms. Klein, the Chair of the audit committee, as such Audit Committee Financial Expert. As previously stated, Ms. Klein is an independent director.

The audit committee operates under a written charter, a current copy of which is attached to this proxy statement as Appendix A and is available on our website,www.cabotcmp.com. The audit committee reviews and reassesses the adequacy of the audit committee charter on an annual basis. The audit committee has established procedures for the receipt, retention, and treatment of complaints received regarding accounting, internal accounting controls or auditing matters, as well as for thepre-approval of services provided by our independent auditors, both of which are also available on our website,www.cabotcmp.com. A current copy of the procedures for the pre-approval of services provided by our independent auditors is attached to this proxy statement as Appendix B. As set forth in the audit committee charter, the audit committee is also responsible for the review and approval of any related party transaction in advance of the company entering into any such transaction; since April 2002, we have not been engaged in any related party transactions and none have been proposed to the audit committee for consideration.

The audit committee met eight times during fiscal year 20142017 and did not take action by written consent, and has met twicethree times since fiscal year end with respect to the audit of our fiscal year 2014

2017 financial statements and related and other matters, and has not taken action by written consent. In fulfillment of the audit committee’s responsibilities for fiscal year 2014,2017, Ms. Klein, the audit committee Chair, reviewed our Annual Report on Form10-K for the fiscal year ended September 30, 20142017 (as did the other members of the committee and board of directors), and our Quarterly Reports on Form10-Q before we filed them, and Ms. Klein and other members of the audit committee (and board of directors) also reviewed quarterly earnings announcements and related matters before we released them.

Compensation Committee.The members of the compensation committee are currently Messrs. Reilly and Wild, and Ms. Whitney (Chair), each of whom the board determined was during fiscal year 2017 and is now an “independent” director as defined by NASDAQ Marketplace Rules and as defined in applicable rules adopted by the SEC. Further, the members of the compensation committee each satisfy the enhanced eligibility requirements applicable to compensation committee members of listed companies set forth in NASDAQ listing standards.

The functions of the compensation committee include include:

reviewing and approving the compensation and benefits for our employees, employees;

evaluating and deciding upon the compensation of our chief executive officer, officer;

evaluating and deciding upon the compensation of our other executive officers, which is done following consultation with our chief executive officer, officer;

monitoring the administration of our employee benefit plans, plans;

authorizing and ratifying stock option grants, restricted stock and restricted stock unit awards, other equity awards (such as performance share unit awards), and other incentive arrangements,arrangements; and,

authorizing employment and related agreements.

		2018 Proxy Statement    14

Our chief executive officer is neither present for voting or deliberation on, nor votes upon decisions relating to, his compensation. In addition, our chief executive officer does not vote upon decisions related to the compensation of our other executive officers. Also, our vice president of human resources and her staff support the compensation committee in its work by providing input and recommendations on the overall mix and forms of executive compensation as directed by the compensation committee. Our vice president of human resources and human resources staff do not make decisions regarding the amount of compensation for our named executive officers or other executive officers.

The compensation committee has engaged the services of aan independent compensation consultant, which reports directly to the committee. Prior to April 2017, W.T. Haigh & Company, Inc. (“W.T. Haigh”), which reports directly served as the independent compensation consultant to the committee.committee, and effective April 2017, the committee has engaged Meridian Compensation Partners, LLC (“Meridian”) as its independent compensation consultant. The consultant has been engaged to advise the compensation committee on executive officer compensation and equity incentive matters and trends and to perform benchmark comparison analysis of compensation practices of peer companies. From time to time, and as part of the compensation committee’s ongoing and annual reviews of executive officer compensation matters, the consultant recommends specific ranges of compensation for our executive officers, including our named executive officers, based on information provided by the committee regarding different performance scenarios and desired positioning with respect to market placement.compensation ranges. The consultant also advises the nominating and corporate governance committee onnon-employee director compensation matters. The consultant provides no other services to our company. The compensation committee also has reviewed the independence of the consultant in light of SEC rules and NASDAQ listing standards regarding compensation consultants and has concluded that the consultant’s work for the committee and for the nominating and corporate governance committee is independent and does not raise any conflict of interest.

The members of the compensation committee are Messrs. Birgeneau, Fuller (Chairman), Hill, Mooney and Xia, each of whom was during fiscal year 2014 and is now an “independent” director as defined in Rule 4200(a)(15) of the NASDAQ Marketplace Rules and as defined in applicable rules adopted by the SEC. Further, the members of the compensation committee each satisfy the enhanced eligibility requirements applicable to compensation committee members of listed companies set forth in newly approved NASDAQ listing standards. The compensation committee operates under a written charter that addresses compensation matters, a current copy of which is available on our website,www.cabotcmp.com. The compensation committee reviews and reassesses the adequacy of the compensation committee charter (including under NASDAQ listing standards) on an annual basis. The compensation committee met six times during fiscal year 20142017 and did not taketook action by written consent once, and has met fourthree times since the fiscal year end with respect to 20142017 annual bonuses, salary increases, equity awards (including stock option grants, and restricted stock awards,unit and performance share unit awards), and other matters, and tookhas taken action by written consent twice.

Nominating and Corporate Governance Committee.    The functions of the nominating and corporate governance committee include reviewing and recommending a slate of nominees for the election of directors, recommending changes in the number, classification and term of directors, reviewing nominations by stockholders with regard to the nomination process, reviewing and recommending compensation and other matters for our non-employee directors, and attending to general corporate governance matters.    The members of

the nominating and corporate governance committee are currently Messrs. Frazee (Chairman), FullerHill (Chair) and WilkinsonWild, and Ms. Klein, each of whom was during fiscal year 20142017 and is now an “independent” director as defined in Rule 4200(a)(15) of theby NASDAQ Marketplace Rules and as defined in applicable rules adopted by the SEC. Mr. Frazee will cease to be a member when he ceases to be a director as of the upcoming annual meeting; as of such time, another independent director will become a member

The functions of the nominating and corporate governance committee include:

The nominating and corporate governance committee operates under a formalwritten charter that addresses the nominations process and such related matters as may be required under the federal securities laws and NASDAQ listing requirements, a current copy of which is available on our website,www.cabotcmp.com. The nominating and corporate governance committee reviews and reassesses the adequacy of the nominating and corporate

		2018 Proxy Statement    15

governance charter on an annual basis. The nominating and corporate governance committee met threefour times during fiscal year 2014,2017, did not take action by written consent, and has met three timesonce since fiscal year end and tookhas not taken action by written consent once.consent. The nominating and corporate governance committee acted unanimously to recommend the nomination of the Class IIIII director nominees to the board of directors, subject to stockholder approval, as discussed in “ELECTION OF DIRECTORS,” above.

Criteria for Nominating Directors

The nominating and corporate governance committee considers candidates to fill new directorships created by expansion and vacancies that may occur and makes recommendations to the board of directors with respect to such candidates. The nominating and corporate governance committee considers suggestions from many sources regarding possible candidates for director and will consider nominees recommended by stockholders. Any such stockholder nominations, together with appropriate biographical information, should be submitted to the Chairman of the nominating and corporate governance committee, c/o the Secretary of our company at our offices at 870 North Commons Drive, Aurora, Illinois 60504. To be included in the proxy statement, such nomination must be received by the Secretary of our company not later than the 120th day prior to the first anniversary of the date of the preceding year’s proxy statement.

In fiscal year 2014,2017, we did not pay a fee to any third party to identify or evaluate potential director nominees; however, in the future we may pay a fee to a third party to identify or evaluate potential director nominees if the need arises, given the important role our directors play in guiding our strategic direction and overseeing the management of our company.

Board candidates are selected based upon various criteria including, their but not limited to, their:

The nominating and corporate governance committee and board of directors review these factors, including diversity, in considering candidates for board membership. Board members are expected to prepare for, attend and participate in all board of directors and applicable committee meetings, and our annual meetings of stockholders. The nominating and corporate governance committee considers a director’s past attendance record, participation and contribution to the board of directors in considering whether to recommend the reelection of such director.

		2018 Proxy Statement    16

Compensation of Directors

The following table shows information concerning the compensation that the company’snon-employee directors earned during the last completed fiscal year ended September 30, 2014.2017. A director who is also our employee receives no additional compensation for his or her services as a director.

2014Fiscal Year 2017 Director Compensation

Name		Fees Earned or Paid in Cash ($)1				Stock Awards ($)2				Options Awards ($)2				All Other Compensation ($)				Total ($)
Robert J. Birgeneau			70,000				89,600				99,591				—				259,191
John P. Frazee, Jr.			97,500				89,600				99,591				—				286,691
H. Laurance Fuller			95,000				89,600				99,591				—				284,191
Richard S. Hill			82,500				89,600				99,591				—				271,691
Barbara A. Klein			101,250				89,600				99,591				—				290,441
Edward J. Mooney			70,000				89,600				99,591				—				259,191
Steven V. Wilkinson			88,750				89,600				99,591				—				277,941
Bailing Xia			70,000				89,600				99,591				—				259,191

Name		Fees Earned or Paid in Cash ($)1				Stock Awards ($)2				Option Awards ($)2				All Other Compensation ($)				Total ($)
William P. Noglows			140,000				93,883				94,760				5,043				333,686
Robert J. Birgeneau3			39,000				—				—				3,272				42,272
Richard S. Hill			115,000				93,883				94,760				2,717				306,360
Barbara A. Klein			115,000				93,883				94,760				3,434				307,077
Paul J. Reilly4			51,250				187,766				94,760				6,975				340,751
Susan M. Whitney			115,000				93,883				94,760				3,238				306,881
Geoffrey Wild			90,000				93,883				94,760				—				278,643
Steven V. Wilkinson3			39,000				—				—				4,950				43,950
Bailing Xia3			39,000				—				—				—				39,000

 

1	Includes an annual retainer fee and committee fee, and, as applicable, committee chairperson annual retainer fees, both earned quarterly, and, as applicable, committee chairperson annual retainer fees, earned annually, each as discussed in more detail below. Dollar amounts are comprised as follows:

 

Name		Annual Retainer Fee				Committee Membership Fees				Committee Chair Fee
Mr. Birgeneau		$	60,000			$	10,000
Mr. Frazee, Jr.*		$	60,000			$	22,500			$	15,000
Mr. Fuller**		$	60,000			$	20,000			$	15,000
Mr. Hill		$	60,000			$	22,500
Ms. Klein***		$	60,000			$	22,500			$	18,750
Mr. Mooney		$	60,000			$	10,000
Mr. Wilkinson***		$	60,000			$	22,500			$	6,250
Mr. Xia		$	60,000			$	10,000

Name		Annual Retainer Fee				Committee   Chair Fee				Non- Executive Board  Chair Fee
Mr. Noglows			$90,000				—				$50,000
Mr. Birgeneau			$39,000				—				—
Mr. Hill*			$90,000				$25,000				—
Ms. Klein**			$90,000				$25,000				—
Mr. Reilly			$51,250				—				—
Ms. Whitney***			$90,000				$25,000				—
Mr. Wild			$90,000				—				—
Mr. Wilkinson			$39,000				—				—
Mr. Xia			$39,000				—				—

*

Nominating and corporate governance committee chairmanchair

 

**

CompensationAudit committee chairmanchair

 

***

AuditCompensation committee chair (Mr. Wilkinson served until the 2014 annual meeting of stockholders in March 2014 and Ms. Klein has served since such time)

2     The amounts in the column headed “Stock Awards” represent the aggregate award date fair value of awards made in fiscal year 2017 computed in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 718, Stock Compensation (“ASC 718”). For these restricted stock unit awards, the fair value is equal to the underlying value of the stock and is calculated using the closing price of our common stock on the award date. The actual value realized by anon-employee

The amounts in the column headed “Stock Awards” represent the aggregate award date fair value of awards made in fiscal year 2014 computed in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 718, Stock Compensation (“ASC 718”). For these restricted stock unit awards, the fair value is equal to the underlying value of the stock and is calculated using the closing price of our common stock on the award date. The actual value realized by a non-employee director related to restricted stock unit awards will depend on the market value of our common stock on the date the underlying stock is sold following vesting of the awards.

The amounts in the column headed “Option Awards” represent the aggregate grant date fair value of grants in fiscal year 20142017 computed in accordance with ASC 718 (see Note 1113 of Notes to Consolidated Financial Statements included in Item 8 of Part II of our Annual Report on Form10-K for fiscal year 20142017 for a description of the assumptions used in that computation). The actual value realized by anon-employee director related to option awards will depend on the difference between the market value of our common stock on the date the option is exercised and the exercise price of the option.

		2018 Proxy Statement    17

The award date fair market value of each “Stock Award” and the grant date fair market value of each “Option Award” awarded or granted to ournon-employee directors during fiscal year 2017, computed in accordance with ASC 718 excluding(excluding the impact of estimated forfeitures for service-based vesting conditions, of each “Stock Award” awarded to our non-employee directors during fiscal year 2014conditions), is as follows:

Name		Award Date				Number of Restricted Stock Units				Award Date Fair Value ($)
Mr. Birgeneau			3/4/14				2,000				89,600
Mr. Frazee			3/4/14				2,000				89,600
Mr. Fuller			3/4/14				2,000				89,600
Mr. Hill			3/4/14				2,000				89,600
Ms. Klein			3/4/14				2,000				89,600
Mr. Mooney			3/4/14				2,000				89,600
Mr. Wilkinson			3/4/14				2,000				89,600
Mr. Xia			3/4/14				2,000				89,600

The grant date fair market value computed in accordance with ASC 718 (such amount is included in the amounts under “Option Awards” in the 2014 Director Compensation Table), and the grant date fair market value computed in accordance with SFAS 123R, excluding the impact of estimated forfeitures for service-based vesting conditions, of each “Option Award” granted to our non-employee directors during fiscal year 2014 is as follows:

Name		Grant Date				Number of Options				Grant Date Fair Value ($)				Award or   Grant Date				Number of   Restricted Stock                Units				Award Date Fair           Value ($)				Number of        Options				Grant Date   Fair Value ($)
Mr. Noglows															3/7/17				1,352				93,833				4,811				94,760
Mr. Birgeneau			3/4/14				6,000				99,591				—				—				—				—				—
Mr. Frazee			3/4/14				6,000				99,591
Mr. Fuller			3/4/14				6,000				99,591
Mr. Hill			3/4/14				6,000				99,591				3/7/17				1,352				93,833				4,811				94,760
Ms. Klein			3/4/14				6,000				99,591				3/7/17				1,352				93,833				4,811				94,760
Mr. Mooney			3/4/14				6,000				99,591
Mr. Reilly															3/7/17				2,704				187,766				4,811				94,760
Ms. Whitney															3/7/17				1,352				93,833				4,811				94,760
Mr. Wild															3/7/17				1,352				93,833				4,811				94,760
Mr. Wilkinson			3/4/14				6,000				99,591				—				—				—				—				—
Mr. Xia			3/4/14				6,000				99,591				—				—				—				—				—

During fiscal year 2014,2017, no stock awards toheld by any of ournon-employee or other directors were modified or cancelled (forfeited).

The aggregate number of stock awards and the aggregate number of stock option awards forheld by eachnon-employee director that were outstanding as of the end of fiscal year 20142017 are as follows:

 

		Aggregate Number of Awards Outstanding as of September  30, 2014								Aggregate Number of Awards   Outstanding as of September  30,                               2017
Name		Stock Awards*				Option Awards				Stock Awards*				Option Awards
Mr. Noglows											1,352				81,949
Mr. Birgeneau			2,000				52,816				—				—
Mr. Frazee			2,000				76,026
Mr. Fuller			2,000				61,520
Mr. Hill			2,625				25,500				1,352				20,449
Ms. Klein			2,000				63,696				1,352				64,561
Mr. Mooney			2,000				52,816
Mr. Reilly											2,704				4,811
Ms. Whitney											1,977				27,949
Mr. Wild											1,977				27,949
Mr. Wilkinson			2,000				61,520				—				68,454
Mr. Xia			2,000				72,400				—				10,454

 

*

Restricted Stock Units.

Ournon-employee directors received an aggregate of 48,000 stock options28,866 stockoptions and 16,0009,464 restricted stock units in fiscal year 2014.2017.

3	Messrs. Birgeneau’s, Wilkinson’s and Xia’s terms expired at the 2017 annual meeting of stockholders in March 2017.

4	Mr. Reilly was elected to the board of directors effective March 7, 2017.

As provided in our Corporate Governance Guidelines and the nominating and corporate governance committee charter, the nominating and corporate governance committee is responsible for reviewing and recommending to the board of directors compensation (cash and equity) fornon-employee directors. The committee does this through review of director compensation benchmark information and analysis and recommendation provided by W.T. Haigh,the independentnon-employee director compensation consultant to the committee.committee, which as of April 2017 is Meridian, and prior to that was W.T. Haigh.

		2018 Proxy Statement    18

As a resultpreviously disclosed, the board of such review following the close of fiscal year 2010, and confirmed pursuant to an additional review following the close of fiscal year 2013,directors approved our currentnon-employee director compensation program effective March 2011 at the time of our annual meeting in March 2016, with the boardobjective of directors, upon the recommendationcontinuing our company’s ability to attract high caliber and experienced individuals to serve as directors. Ournon-employee director compensation program consists of the nominating and corporate governance committee, approved certain changes to the compensation program for non-employee directors, as summarized below, and since then, non-employee directors have been eligible for the following compensation:elements:

**2	To the extent a special committee is established by board of directors to address a unique matter, a committee meeting fee of $1,500 will be provided.

Upon anon-employee director’s termination of service as a director of the company for reason of Death, Disability or a Change in Control, as defined in the 2000 Equity Incentive Plan, the 2012 Omnibus Incentive Plan and/or an award agreement, theeach grant or award ofnon-qualified stock options and restricted stock units held by the director will be fully vested.vest in full. In addition, if at the time of termination of service for any reason other than by reason of Cause, Death, Disability or a Change in Control, as defined in the 2000 Equity Incentive Plan, the 2012 Omnibus Incentive Plan and/or an award agreement, thenon-employee director has completed at least two full terms as a director, as defined in our bylaws, theeach grant or award ofnon-qualified stock options and restricted stock units held by the director will be fully vested.vest in full.

Under our Directors’ Cash Compensation Umbrella Program, which only applies tonon-employee directors and is filed as an exhibit to our Annual Report on Form10-K filed with the SEC on December 10, 2003, eachnon-employee director may choose to receive his or her compensation either in cash, in fully vested restricted stock under our 2012 Omnibus Incentive Plan (and formerly under our 2000 Equity Incentive Plan) (as of the date the fees are earned, the fees would be converted into the equivalent number of fully vested restricted shares, which would be beneficially owned and reported on Form 4 filings), or as deferred compensation under our Directors’ Deferred Compensation Plan, as amended September 23, 2008, which first became effective in March 2001, and is filed as an exhibit to our Annual Report on Form10-K filed with the SEC on November 25, 2008. At present, non-employee directors receive their annual retainer and committee chair and member fees on a quarterly basis. Non-employee directors also are eligible for reimbursement of travel and other out-of-pocket costs incurred in attending meetings. Non-employee directors are not eligible for any other compensation arrangement.

Prior to January 1, 2008, Messrs. Frazee, Fuller, Mooney, and Wilkinson had each elected to defer his compensation to future periods under the Directors’ Deferred Compensation Plan. Messrs. Frazee and Wilkinson, as of January 1, 2008, and Mr. Mooney, as of January 1, 2009, each elected to no longer defer his compensation under the plan. Under the Directors’ Deferred Compensation Plan,

		2018 Proxy Statement    19

deferred amounts are payable only in the form of our common shares. A participating director is required to elect a date on which deferred compensation will begin to be distributed, which date generally must be at least two years after the end of the year deferrals are made and no later than the date of termination. As of the date the compensation is earned, the fees are converted into the right to acquire the equivalent number of shares of common stock at the end of the deferral period. These rights to acquire shares under the Directors’ Deferred Compensation Plan are reported as beneficially owned on Form 4 filings for each participating director. As of January 9, 2015, an aggregate of approximately $1,965,790 of directors’ compensation wasdirector; nonon-employee directors currently participate in, and no amounts are deferred under, the plan,Directors’ Deferred Compensation Plan. At present,non-employee directors receive their annual retainer and ascommittee chair fees on a quarterly basis.Non-employee directors also are eligible for reimbursement of September 30, 2014, the amount was $1,942,040.travel and otherout-of-pocket costs incurred in attending meetings.Non-employee directors are not eligible for any other compensation arrangement.

Compensation Committee Interlocks and Insider Participation

None of the current or former members of the compensation committee are or have been our employees.

FEES OF INDEPENDENT AUDITORS AND AUDIT COMMITTEE REPORT

Fees Billed by Independent Auditors

During fiscal years 20142017 and 2013,2016, the audit committeepre-approved 100% of all audit andnon-audit services provided by our independent auditors, PricewaterhouseCoopers LLP, an independent registered public accounting firm. For suchpre-approval of services, the audit committee follows its policy for thepre-approval of services provided by our independent auditors, a current copy of which is attached to this proxy statement as Appendix B and also is available on ourweb-site,www.cabotcmp.com. The policy requires advance approval of all audit, audit-related, tax services and other services performed by the independent auditor. This policy provides forpre-approval by the audit committee of permitted services before the independent auditor is engaged to perform them. The audit committee has delegated to the chair of the audit committee authority to approve permitted services. The following table presents fees for audit services rendered by PricewaterhouseCoopers LLP for the audit of our annual financial statements for the fiscal year ended September 30, 2014,2017, and September 30, 2013,2016, and fees billed for other services rendered by PricewaterhouseCoopers LLP during those periods.

Fees		Fiscal Year Ended September 30, 2014 ($)				Fiscal Year Ended September 30, 2013 ($)
Audit Fees(1)			1,845,545				1,544,009
Audit-Related Fees(2)			—				—
Tax Fees(3)			788,061				493,743
All Other Fees(4)			4,500				4,500
Total			2,638,106				2,042,252

Fees		Fiscal Year Ended   September 30, 2017 ($)				Fiscal Year Ended   September 30, 2016 ($)
Audit Fees1			1,686,826				2,058,164
Audit-Related Fees2			20,000				93,000
Tax Fees3			204,813				123,843
All Other Fees4			4,500				4,500
Total			1,916,139				2,279,507

 

(1)1

Audit Fees include fees for professional services rendered by PricewaterhouseCoopers LLP for the audit of our annual financial statements and internal control over financial reporting and review of financial statements included in our Form10-Q and for services that normally would be provided by PricewaterhouseCoopers LLP in connection with statutory and regulatory filings or engagements. In addition to including fees for services necessary to perform an audit or review in accordance with generally accepted auditing standards, this category also may include services that generally only PricewaterhouseCoopers LLP reasonably can provide, such as comfort letters, statutory audits, attest services, consents and assistance with and review of documents filed with the SEC.

 

(2)
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Report of the Audit Committee

The following report of the audit committee does not constitute soliciting material and should not be deemed filed or incorporated by reference into any other of our filings under the Securities Act of 1933 or the Securities Exchange Act of 1934, except to the extent we specifically incorporate this report by reference therein.

The audit committee of the board of directors is responsible for providing independent, objective oversight of our accounting and system of internal controls, the quality and integrity of our financial reports, and the independence and the selection, appointment, retention, compensation and oversight of the performance of our independent auditors. The audit committee is composed of independent directors and operates under a written charter, a current copy of which is attached to this proxy statement as Appendix A and is available on our website,www.cabotcmp.com. The audit committee reviews and reassesses the adequacy of the audit committee charter on an annual basis. Our board of directors has determined that the audit committee has at least one member who qualifies as an Audit Committee Financial Expert, as defined by relevant Securities and Exchange Commission (“SEC”)SEC rules, and has designated Ms. Klein, the Chair of the committee, as such Audit Committee Financial Expert.

Management is responsible for our internal controls and the financial reporting process. The independent auditors are responsible for performing an independent audit of our financial statements in accordance with generally accepted auditing standards and issuing a report on those financial statements. The audit committee monitors and oversees these processes.

In this context, the audit committee reviewed and discussed the audited financial statements for fiscal year 20142017 with management and with the independent auditors. Specifically, the audit committee has discussed with the independent auditors the matters required to be discussed by Statement on Auditing Standards No. 16 (Communications with Audit Committees), which as of December 31, 2016 is referred to as AS No. 1301, and which include, among other things: