Exhibit 10.1

EXECUTION VERSION

AMENDMENT NO. 6 TO TERM LOAN CREDIT AGREEMENT

dated as of

September 27, 2019,

among

MKS INSTRUMENTS, INC.,

as the Borrower,

the other Loan Parties party hereto,

the Participating Lenders party hereto,

and

BARCLAYS BANK PLC,

as Administrative Agent, Lead Arranger and Bookrunner

AMENDMENT NO. 6 TO TERM LOAN CREDIT AGREEMENT

This AMENDMENT NO. 6 TO TERM LOAN CREDIT AGREEMENT, dated as of September 27, 2019 (this “Agreement”), by and among MKS Instruments, Inc., a Massachusetts corporation (the “Borrower”), the other Loan Parties party hereto, Barclays Bank PLC, as the administrative agent and the collateral agent (in such capacity, the “Administrative Agent”) under the Credit Agreement referred to below, and each Participating Lender (as defined below) party hereto.

RECITALS:

WHEREAS, reference is made to the Term Loan Credit Agreement, dated as of April 29, 2016 (as amended by Amendment No. 1 to Term Loan Credit Agreement, dated as of June 9, 2016, among the Borrower, the Loan Parties party thereto, the Administrative Agent and the other parties thereto, by Amendment No. 2 to Term Loan Credit Agreement, dated as of December 14, 2016, among the Borrower, the Loan Parties party thereto, the Administrative Agent and the other parties thereto, and by Amendment No. 3 to Term Loan Credit Agreement, dated as of July 6, 2017, among the Borrower, the Loan Parties party thereto, the Administrative Agent and the other parties thereto, Amendment No. 4 to Term Loan Credit Agreement, dated as of April 11, 2018, among the Borrower, the Loan Parties party thereto, the Administrative Agent and the other parties thereto, Amendment No. 5 to Term Loan Credit Agreement, dated as of February 1, 2019, among the Borrower, the Loan Parties party thereto, the Administrative Agent and the other parties thereto and as may be further amended, restated, amended and restated, supplemented or otherwise modified from time to time, the “Credit Agreement”), among the Borrower, the Lenders from time to time party thereto and the Administrative Agent (capitalized terms used but not defined herein having the meaning provided in the Credit Agreement), pursuant to which the Lenders provided the Borrower with Term Loans in an aggregate initial principal amount of (i) $780,000,000 (the “Initial Term Loans”) on the Closing Date and (ii) $650,000,000 (the “Tranche B-5 Term Loans”) on the Amendment No. 5 Effective Date;

WHEREAS, concurrently with the effectiveness of this Agreement, the Borrower intends to make a voluntary prepayment, which will be applied to each of the Tranche B-4 Term Loans and the Tranche B-5 Term Loans on a pro rata basis, in aggregate amount of $50,000,000 (the “Prepayment”);

WHEREAS, this Agreement constitutes a Refinancing Amendment, and the Borrower is hereby notifying the Administrative Agent that it is requesting the establishment of Other Term Commitments and/or Other Term Loans, in each case, pursuant to Section 2.15 of the Credit Agreement;

WHEREAS, giving effect to the consummation of the Prepayment concurrently with the effectiveness of this Agreement, the Borrower requests Other Term Loans in an aggregate principal amount of $896,838,687.59 (the “Tranche B-6 Term Facility”; and the loans thereunder, the “Tranche B-6 Term Loans”; the commitments in respect of such Tranche B-6 Term Loans, the “Tranche B-6 Term Commitments”; and the Participating Lenders with Tranche B-6 Term Commitments and any permitted assignees thereof, the “Tranche B-6 Lenders”), which will be available on the Amendment No. 6 Effective Date (as defined below) to (i) refinance all existing Tranche B-4 Term Loans outstanding under the Credit Agreement immediately prior to effectiveness of this Agreement (the “Existing Tranche B-4 Term Loans”) and (ii) refinance all existing Tranche B-5 Term Loans outstanding under the Credit Agreement immediately prior to effectiveness of this Agreement (the “Existing Tranche B-5 Term Loans”; together with the Existing Tranche B-4 Term Loans, the “Existing Term Loans”) and which Tranche B-6 Term Loans shall constitute Other Term Loans and Term Loans (as applicable) for all

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purposes of the Credit Agreement and the other Loan Documents; it being understood that prior to giving effect to the consummation of the Prepayment, the aggregate principal amount of the (i) Existing Tranche B-4 Term Loans immediately prior to effectiveness of this Agreement is $298,463,687.52 and (ii) Existing Tranche B-5 Term Loans immediately prior to effectiveness of this Agreement is $648,375,000.07;

WHEREAS, each Lender holding Existing Term Loans under the Credit Agreement immediately prior to effectiveness of this Agreement (each, an “Existing Lender”) executing and delivering a notice of participation in the Tranche B-4 Term Loans and/or the Tranche B-5 Term Loans, as applicable, in the form attached as Exhibit A hereto (a “Tranche B-6 Participation Notice”) and electing the cashless settlement option therein (each such Lender in such capacity and with respect to the Existing Term Loans so elected, a “Converting Lender” and, together with each other Person executing and delivering a Tranche B-6 Participation Notice or otherwise providing a Tranche B-6 Term Commitment, the “Participating Lenders”) shall be deemed to have exchanged on the Amendment No. 6 Effective Date the aggregate outstanding principal amount of its Existing Term Loans under the Credit Agreement for an equal aggregate principal amount of Tranche B-6 Term Loans under the Credit Agreement;

WHEREAS, the Borrower has appointed Barclays to act, and Barclays agrees to act, as lead arranger and bookrunner in respect of the Tranche B-6 Term Loans;

WHEREAS, Barclays, in its capacity as lead arranger and bookrunner (the “Lead Arranger”), agrees to act as fronting bank for the syndication of the Tranche B-6 Term Loans (in such capacity, the “Fronting Bank”), the Fronting Bank will purchase, and the Existing Lenders will sell to the Fronting Bank, immediately prior to effectiveness of this Agreement, (i) Existing Term Loans of Existing Lenders that do not execute and deliver a Tranche B-6 Participation Notice (the “Non-Participating Lenders”) and (ii) Existing Term Loans of Existing Lenders that execute and deliver a Tranche B-6 Participation Notice and elect the cash settlement option therein (the “Non-Converting Lenders”) (the Loans described in the foregoing clauses (i) and (ii), collectively, the “Reallocated Loans”);

WHEREAS, to the extent there exist any Reallocated Loans, the Fronting Bank shall be deemed to exchange on the Amendment No. 6 Effective Date such Reallocated Loans on a cashless settlement basis for an equal aggregate principal amount of Tranche B-6 Term Loans under the Credit Agreement, and such Reallocated Loans shall promptly thereafter be purchased by Participating Lenders (other than Existing Lenders) (the “New Lenders”), Non-Converting Lenders, and Existing Lenders purchasing additional Tranche B-6 Term Loans, each in accordance with such Participating Lenders’ respective Tranche B-6 Participation Notice and as allocated by the Lead Arranger (with the consent of the Borrower, not to be unreasonably withheld or delayed); and

WHEREAS, contemporaneously with the effectiveness of the Tranche B-6 Term Commitments the Borrower wishes to (a) make certain amendments to the Credit Agreement to provide for the incurrence of the Tranche B-6 Term Loans and (b) make certain other modifications to the Credit Agreement set forth herein.

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NOW, THEREFORE, in consideration of the premises and agreements, provisions and covenants herein contained, the parties hereto agree as follows:

“Amendment No. 6 means Amendment No. 6 to this Agreement, dated as of September 27, 2019, among the Borrower, the other Loan Parties party thereto, the Lenders party thereto, and the Administrative Agent.

“Amendment No. 6 Effective Date” means the “Amendment No. 6 Effective Date” under and as defined in Amendment No. 6.

“Tranche B-6 Commitments” means the “Tranche B-6 Term Commitments” as defined in Amendment No. 6.

“Tranche B-6 Term Facility” means the “Tranche B-6 Term Facility” as defined in Amendment No. 6.

“Tranche B-6 Term Loans” means the “Tranche B-6 Term Loans” as defined in Amendment No. 6.

“Adjusted LIBOR Floor” means 0.00% per annum.

“Applicable Margin” means a percentage per annum equal to (i) for Tranche B-6 Term Loans that are Eurodollar Loans, 1.75% and (ii) for Tranche B-6 Term Loans that are Base Rate Loans, 0.75%.

(d)    The definition of “Maturity Date” is hereby amended and restated in its entirety as follows:

“Maturity Date” means February 2, 2026.

(e)    The definition of “Term Commitment” is hereby amended and restated in its entirety as follows:

“Term Commitment” means, with respect to any Lender, (i) such Lender’s Initial Term Commitment, (ii) such Lender’s Tranche B-1 Commitment, (iii) such Lender’s Tranche B-2 Commitment, (iv) such Lender’s Tranche B-3 Commitment, (v) such Lender’s Tranche B-4 Commitment (vi) such Lender’s Tranche B-5 Commitment and (vii) such Lender’s Tranche B-6 Commitment.

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“Term Loans” means the term loans made by the Term Lenders to the Borrower pursuant to Section 2.01(b); provided that (i) from and after the effectiveness of Amendment No. 1, “Term Loans” shall mean all Tranche B-1 Term Loans made on the Amendment No. 1 Effective Date (through exchange or otherwise) pursuant to Amendment No. 1, (ii) from and after the effectiveness of Amendment No. 2, “Term Loans” shall mean all Tranche B-2 Term Loans made on the Amendment No. 2 Effective Date (through exchange or otherwise) pursuant to Amendment No. 2, (iii) from and after the effectiveness of Amendment No. 3, “Term Loans” shall mean all Tranche B-3 Term Loans made on the Amendment No. 3 Effective Date (through exchange or otherwise) pursuant to Amendment No. 3, (iv) from and after the effectiveness of Amendment No. 4, “Term Loans” shall mean all Tranche B-4 Term Loans made on the Amendment No. 4 Effective Date (through exchange or otherwise) pursuant to Amendment No. 4, (v) from and after the effectiveness of Amendment No. 5, “Term Loans” shall mean (x) all Tranche B-4 Term Loans outstanding as of the Amendment No. 5 Effective Date plus (y) all Tranche B-5 Term Loans made on the Amendment No. 5 Effective Date pursuant to Amendment No. 5 and (vi) from and after the effectiveness of Amendment No. 6, “Term Loans” shall mean all Tranche B-6 Term Loans made on the Amendment No. 6 Effective Date (through exchange or otherwise) pursuant to Amendment No. 6.

“Term Facility” means, the Tranche B-6 Term Facility.

“Subject solely to the terms and conditions set forth herein, each Lender with an Initial Term Commitment severally made a Term Loan to the Borrower in Dollars on the Closing Date in a principal amount equal to its Initial Term Commitment. The aggregate principal amount of Initial Term Commitments for all Lenders was equal to the Term Committed Amount. For the avoidance of doubt, the Borrower made one borrowing under the Initial Term Commitments, which was on the Closing Date, and each Lender’s Initial Term Commitment terminated immediately and without further action on the Closing Date after giving effect to the funding of such Lender’s Initial Term Commitment on such date. Subject to the terms and conditions hereof and of Amendment No. 1, each Lender with a Tranche B-1 Commitment severally made or exchanged, as applicable, on the Amendment No. 1 Effective Date, a Tranche B-1 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-1 Commitment. The aggregate principal amount of Tranche B-1 Commitments as of the Amendment No. 1 Effective Date for all Lenders was $730,000,000. For the avoidance of doubt, the Borrower made one borrowing under the Tranche B-1 Commitments, which was on the Amendment No. 1 Effective Date, and each Lender’s Tranche B-1 Commitment terminated immediately and without further action on the Amendment No. 1 Effective Date after giving effect to the funding of such Lender’s Tranche B-1 Commitment on such date. Subject to the terms and conditions hereof and of Amendment No. 2, each Lender with a Tranche B-2

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Commitment severally made or exchanged, as applicable, on the Amendment No. 2 Effective Date, a Tranche B-2 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-2 Commitment. The aggregate principal amount of Tranche B-2 Commitments as of the Amendment No. 2 Effective Date for all Lenders was $628,175,000. For the avoidance of doubt, the Borrower made one borrowing under the Tranche B-2 Commitments, which was on the Amendment No. 2 Effective Date, and each Lender’s Tranche B-2 Commitment terminated immediately and without further action on the Amendment No. 2 Effective Date after giving effect to the funding of such Lender’s Tranche B-2 Commitment on such date. Subject to the terms and conditions hereof and of Amendment No. 3, each Lender with a Tranche B-3 Commitment severally made or exchanged, as applicable, on the Amendment No. 3 Effective Date, a Tranche B-3 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-3 Commitment. The aggregate principal amount of Tranche B-3 Commitments as of the Amendment No. 3 Effective Date for all Lenders was $573,463,687.50. For the avoidance of doubt, the Borrower made one borrowing under the Tranche B-3 Commitments, which was on the Amendment No. 3 Effective Date, and each Lender’s Tranche B-3 Commitment terminated immediately and without further action on the Amendment No. 3 Effective Date after giving effect to the funding of such Lender’s Tranche B-3 Commitment on such date. Subject to the terms and conditions hereof and of Amendment No. 4, each Lender with a Tranche B-4 Commitment severally made or exchanged, as applicable, on the Amendment No. 4 Effective Date, a Tranche B-4 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-4 Commitment. The aggregate principal amount of Tranche B-4 Commitments as of the Amendment No. 4 Effective Date for all Lenders was $348,463,687.50. For the avoidance of doubt, the Borrower made only one borrowing under the Tranche B-4 Commitments, which was on the Amendment No. 4 Effective Date and each Lender’s Tranche B-4 Commitment terminated immediately and without further action on the Amendment No. 4 Effective Date after giving effect to the funding of such Lender’s Tranche B-4 Commitment on such date. Subject to the terms and the conditions hereof and of Amendment No. 5, each Lender with a Tranche B-5 Commitment severally made, on the Amendment No. 5 Effective Date, a Tranche B-5 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-5 Commitment. The aggregate principal amount of Tranche B-5 Commitments as of the Amendment No. 5 Effective Date for all Lenders was $650,000,000. For the avoidance of doubt, the Borrower made only one borrowing under the Tranche B-5 Commitments, which was on the Amendment No. 5 Effective Date and each Lender’s Tranche B-5 Commitment terminated immediately and without further action on the Amendment No. 5 Effective Date after giving effect to the funding of such Lender’s Tranche B-5 Commitment on such date. Subject to the terms and conditions hereof and of Amendment No. 6, each Lender with a Tranche B-6 Commitment severally agrees to make or exchange, as applicable, on the Amendment No. 6 Effective Date, a Tranche B-6 Term Loan to the Borrower in Dollars in an amount equal to such Lender’s Tranche B-6 Commitment. The aggregate principal amount of Tranche B-6 Commitments as of the Amendment No. 6 Effective Date for all Lenders is $896,838,687.59. The Borrower may make only one borrowing under the Tranche B-6 Commitments, which shall be on the Amendment No. 6 Effective Date and each Lender’s Tranche B-6 Commitment shall terminate immediately and without further action on the Amendment No. 6 Effective Date after giving effect to the funding of such Lender’s Tranche B-6 Commitment on such date.”

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“Prepayment Premium. In the event that, on or prior to the date that is six (6) months after the Amendment No. 6 Effective Date, the Borrower (x) makes any prepayment of Term Loans in connection with any Repricing Transaction or (y) effects any amendment of this Agreement resulting in a Repricing Transaction, the Borrower shall pay to the Administrative Agent, for the ratable account of each applicable Term Lender, (I) in the case of clause (x), a prepayment premium of 1.00% of the amount of the Term Loans being prepaid and (II) in the case of clause (y), a payment equal to 1.00% of the aggregate amount of the applicable Term Loans outstanding immediately prior to such amendment that are subject to such Repricing Transaction.”

Section 9.15    “Acknowledgement Regarding Any Supported QFCs. To the extent that the Loan Documents provide, through a guarantee or otherwise, for hedge agreements or any other agreement or instrument that is a QFC (such support, “QFC Credit Support” and each such QFC a “Supported QFC”), the parties acknowledge and agree as follows with respect to the resolution power of the Federal Deposit Insurance Corporation under the Federal Deposit Insurance Act and Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act (together with the regulations promulgated thereunder, the “U.S. Special Resolution Regimes”) in respect of such Supported QFC and QFC Credit Support (with the provisions below applicable notwithstanding that the Loan Documents and any Supported QFC may in fact be stated to be governed by the laws of the State of New York and/or of the United States or any other state of the United States):

(a)    In the event a Covered Entity that is party to a Supported QFC (each, a “Covered Party”) becomes subject to a proceeding under a U.S. Special Resolution Regime, the transfer of such Supported QFC and the benefit of such QFC Credit Support (and any interest and obligation in or under such Supported QFC and such QFC Credit Support, and any rights in property securing such Supported QFC or such QFC Credit Support) from such Covered Party will be effective to the same extent as the transfer would be effective under the U.S. Special Resolution Regime if the Supported QFC and such QFC Credit Support (and any such interest, obligation and rights in property) were governed by the laws of the United States or a state of the United States. In the event a Covered Party or a BHC Act Affiliate of a Covered Party becomes subject to a proceeding under a U.S. Special Resolution Regime, Default Rights

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under the Loan Documents that might otherwise apply to such Supported QFC or any QFC Credit Support that may be exercised against such Covered Party are permitted to be exercised to no greater extent than such Default Rights could be exercised under the U.S. Special Resolution Regime if the Supported QFC and the Loan Documents were governed by the laws of the United States or a state of the United States. Without limitation of the foregoing, it is understood and agreed that rights and remedies of the parties with respect to a Defaulting Lender shall in no event affect the rights of any Covered Party with respect to a Supported QFC or any QFC Credit Support.

(b)    As used in this Section 9.15, the following terms have the following meanings:

“BHC Act Affiliate” of a party means an “affiliate” (as such term is defined under, and interpreted in accordance with, 12 U.S.C. 1841(k)) of such party.

“Covered Entity” means any of the following:

i. a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b);

ii. a “covered bank” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or

iii. a “covered FSI” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b).

“Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

“QFC” has the meaning assigned to the term “qualified financial contract” in, and shall be interpreted in accordance with, 12 U.S.C. 5390(c)(8)(D).”

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[Signature Pages Follow]

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IN WITNESS WHEREOF, each of the undersigned has caused its duly authorized officer to execute and deliver this Agreement as of the date first set forth above.

[Signature Page to Amendment No. 6 to Term Loan Credit Agreement]

[Signature Page to Amendment No. 6 to Term Loan Credit Agreement]

[Signature Page to Amendment No. 6 to Term Loan Credit Agreement]

EXHIBIT A

Form of Tranche B-6 Participation Notice

Date: September [    ], 2019

Barclays Bank PLC, as Administrative Agent

745 7^th Avenue

New York NY 10019

Attn: Robert Walsh

Phone: (212) 526 6047

Email: robert.xa.walsh@barclays.com

MKS Instruments, Inc.

Tranche B-6 Participation Notice

Ladies and Gentlemen:

Reference is made to Amendment No. 6 (the “Amendment”) to that certain Term Loan Credit Agreement, dated as of April 29, 2016 (as amended Amendment No. 1 (as defined therein), Amendment No. 2 (as defined therein), Amendment No. 3 (as defined therein), Amendment No. 4 (as defined therein), Amendment No. 5 (as defined therein) and the Amendment, and as may be further amended, restated, amended and restated, supplemented or otherwise modified from time to time, the “Credit Agreement”), by and among MKS Instruments, Inc., a Massachusetts corporation (the “Borrower”), the Lenders from time to time party thereto, and Barclays Bank PLC, as administrative agent (in such capacity, the “Administrative Agent”). Unless otherwise specified herein, capitalized terms used but not defined herein are used as defined in the Amendment.

By delivery of this letter agreement (this “Tranche B-6 Participation Notice”), each of the undersigned (each a “Participating Lender”), hereby irrevocably consents to the Amendment and the amendment of the Credit Agreement contemplated thereby and (check as applicable):

NAME OF PARTICIPATING LENDER: _____________________________________________ AMOUNT OF EXISTING TRANCHE B-4 TERM LOANS OF SUCH PARTICIPATING LENDER: $____________________

AMOUNT OF EXISTING TRANCHE B-5 TERM LOANS OF SUCH PARTICIPATING LENDER: $____________________

Please note that, regardless of whether you elect the Cashless Settlement Option or the Cash Settlement Option, the Lead Arranger may, in its sole discretion, (i) in the case of the Cashless Settlement Option, elect to exchange (on a cashless basis) less than 100% of your existing hold, in which case the difference between the current amount and the allocated amount will be prepaid to each of your funds on the Amendment No. 6 Effective Date on a pro rata basis and/or (ii) in the case of the Cash Settlement Option, allocate to you less than 100% of your existing hold, in which case your allocated amount will be allocated to each of your funds on a pro rata basis.

[Signature Page Follows]

ANNEX I

REALLOCATED LOANS

Exhibit 99.1

MKS Instruments Completes Fifth Repricing and Makes a Voluntary $50 Million

Prepayment on its Secured Term Loan

Cumulative Actions since Origination Have Resulted in Total Voluntary Prepayments of $525 Million

ANDOVER, Mass., October 1, 2019 (GLOBE NEWSWIRE) — MKS Instruments, Inc. (NASDAQ: MKSI), a global provider of technologies that enable advanced processes and improve productivity, announced today that it successfully completed the repricing of its existing secured term loan. The lenders have agreed to an amendment that results in a reduction of the interest rate spread on the two existing tranches of the secured term loan from LIBOR plus 2.00% and LIBOR plus 2.25%, respectively, to LIBOR plus 1.75%. This transaction also combined the two existing tranches into one tranche with a maturity date in February 2026. Based upon the current interest rate, the annualized non-GAAP interest savings from this repricing is approximately $4 million.

In addition, the Company announced that it has made a voluntary $50 million prepayment of principal on its secured term loan, reducing the outstanding principal to approximately $897 million as of September 27, 2019, from approximately $947 million at June 30, 2019. Based upon the current interest rate, this voluntary prepayment results in an additional annualized non-GAAP interest savings of approximately $1.9 million.

“We continue to deliver on our commitment to reduce our leverage and interest costs. This marks the fifth repricing and tenth voluntary prepayment since loan origination in April 2016. These actions demonstrate our consistent execution in reducing our leverage as well as reducing our annualized non-GAAP interest rate costs by almost $6 million, based upon the current interest rate,” said Seth H. Bagshaw, Senior Vice President and Chief Financial Officer.

Barclays acted as sole arranger for this secured term loan repricing and amendment.

About MKS Instruments

MKS Instruments, Inc. is a global provider of instruments, subsystems and process control solutions that measure, monitor, deliver, analyze, power and control critical parameters of advanced manufacturing processes to improve process performance and productivity for our customers. Our products are derived from our core competencies in pressure measurement and control, flow measurement and control, gas and vapor delivery, gas composition analysis, residual gas analysis, leak detection, control technology, ozone generation and delivery, power, reactive gas generation, vacuum technology, lasers, photonics, sub-micron positioning, vibration control, optics and laser-based manufacturing solutions. We also provide services relating to the maintenance and repair of our products, installation services and training. Our primary served markets include semiconductor, industrial technologies, life and health sciences, and research and defense. Additional information can be found at www.mksinst.com.

Use of Non-GAAP Financial Measure

Non-GAAP interest expense excludes amortization of debt issuance costs. This non-GAAP measure is not in accordance with U.S. Generally Accepted Accounting Principles (GAAP). MKS management believes the presentation of this non-GAAP financial measure is useful to investors for comparing prior periods and analyzing ongoing business trends and financial results. On an annualized basis, GAAP interest savings, at the current interest rate, is approximately $7 million, which includes approximately $1 million of amortization of deferred financing costs.

Forward-Looking Statements

This release contains a forward-looking statement within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27 of the Securities Act, and Section 21E of the Securities Exchange Act regarding MKS’ interest expense. This statement is only a prediction. Actual events or results may differ materially from those in the forward-looking statement set forth herein. Readers are referred to MKS’ filings with the Securities and Exchange Commission, including its most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q for a discussion of these and other important risk factors concerning MKS and its operations. MKS is under no obligation to, and expressly disclaims any obligation to, update or alter its forward-looking statements, whether as a result of new information, future events or otherwise.

Company Contact:

Seth H. Bagshaw

Senior Vice President, Chief Financial Officer and Treasurer

Telephone: 978.645.5578

Email: seth.bagshaw@mksinst.com

Investor Relations Contacts:

Monica Gould

The Blueshirt Group

Telephone: 212.871.3927

Email: monica@blueshirtgroup.com

Lindsay Grant Savarese

The Blueshirt Group

Telephone: 212.331.8417

Email: lindsay@blueshirtgroup.com