Results of Operations and Financial Condition. On August 5, 2026, MKS Inc. announced its financial results for the quarter ended June 30, 2026. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be d…

The filing describes an amendment to the stock incentive plan, not a management change.

Results of Operations and Financial Condition. On May 6, 2026, MKS Inc. announced its financial results for the quarter ended March 31, 2026. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be dee…

Executive Vice President, General Counsel and Secretary — Kathleen F. Burke: Kathleen F. Burke notified the company of her retirement but will remain as a special advisor until July 1, 2026.

Results of Operations and Financial Condition. On February 17, 2026, MKS Inc. announced its financial results for the quarter ended December 31, 2025. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall…

Entry into a Material Definitive Agreement. Notes Offering On February 4, 2026, MKS Inc. (the “Company”) completed its previously announced private offering (the “Offering”) of €1.0 billion aggregate principal amount of senior notes due 2034 (the “Notes”). The Notes were sold in a private placement to persons reasonably believed to be qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”), and to non-U.S. persons outside the…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth in

Other Events. Notes Offering On January 26, 2026, MKS Inc. (the “Company”) issued a press release announcing a proposed offering (the “Offering”) of €1.0 billion aggregate principal amount of senior notes due 2034 (the “Notes”) in a private placement to persons reasonably believed to be qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”) and to non-U.S. persons outside the United States in reliance on Regulation S under t…

of this Current Report on Form 8-K contains financial guidance with respect to the Company’s anticipated financial results for the three months ended December 31, 2025. This financial guidance is based on a number of assumptions, and the Company has not yet completed its closing procedures with respect to its quarter and year ended December 31, 2025. The financial guidance should not be viewed as a substitute for full quarterly and year ended financial statements prepared in accordance with G…

of this Current Report on Form 8-K and Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, except as expressly set forth by specific reference in such a filing. Safe Harbor for Forward-Looking Statements This Current Report on Form 8-K contains “forward-looking statements” withi…

Results of Operations and Financial Condition. On November 5, 2025, MKS Inc. announced its financial results for the quarter ended September 30, 2025. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall…

Results of Operations and Financial Condition. On August 6, 2025, MKS Inc. announced its financial results for the quarter ended June 30, 2025. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be d…

COO — James A. Schreiner: The filing discloses the internal promotion of an existing Executive Vice President to the role of Chief Operating Officer and principal operating officer, which is a standard succession or expansion event rather than a departure.

Material Modification to Rights of Security Holders. The information set forth in

Results of Operations and Financial Condition. On May 7, 2025, MKS Instruments, Inc. announced its financial results for the quarter ended March 31, 2025. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor sh…

Results of Operations and Financial Condition. On February 12, 2025, MKS Instruments, Inc. announced its financial results for the quarter ended December 31, 2024. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that sectio…

Entry into a Material Definitive Agreement. On January 24, 2025 (the “Effective Date”), MKS Instruments, Inc., a Massachusetts corporation (the “Company”), entered into the Fifth Amendment to Credit Agreement (the “Fifth Amendment”), which amends the Credit Agreement, dated as of August 17, 2022, by and among the Company, the lenders and letter of credit issuers party thereto and JPMorgan Chase Bank, N.A., as administrative agent and collateral agent (as amended from time to time, including b…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure under

Results of Operations and Financial Condition. On November 6, 2024, MKS Instruments, Inc. announced its financial results for the quarter ended September 30, 2024. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that sectio…

Director — Wissam Jabre: The filing discloses the appointment of a new director to the board, which is a routine governance event and not a departure of an executive officer.

CFO — Ramakumar Mayampurath: The filing discloses the appointment of a new external CFO, which is a significant management change but not a departure of a sitting executive.

Results of Operations and Financial Condition. On August 7, 2024, MKS Instruments, Inc. announced its financial results for the quarter ended June 30, 2024. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K. The information in this Form 8-K and the Exhibit attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor…

Entry into a Material Definitive Agreement. On July 23, 2024 (the “Effective Date”), MKS Instruments, Inc., a Massachusetts corporation (the “Company”), entered into the Fourth Amendment to Credit Agreement (the “Fourth Amendment”), which amends the Credit Agreement, dated as of August 17, 2022, by and among the Company, the lenders and letter of credit issuers party thereto and JPMorgan Chase Bank, N.A., as administrative agent and collateral agent (as amended from time to time, including by…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The disclosure under

Safe Harbor for Forward-Looking Statements This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended, including the use of proceeds from the offering and the potential effects of entering into the capped call transactions in connection with the pricing of the Notes. These statements are only predictions based…