Management Change/Compensation (Form 8-K)

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Chief Accounting Officer Transition

On November 9, 2026, Brian Harding, Senior Vice President and Chief Accounting Officer of Ultra Clean Holdings, Inc. (the "Company"), was appointed to serve as the Company's Senior Vice President, Finance, effective November 13, 2026 (the "Effective Date"), where he will lead the Company's global financial planning and analysis, finance operations, finance strategy and strategic financial decision support. In addition, Mr. Harding will lead initiatives to advance the Company's finance capabilities through the expansion of artificial intelligence, data analytics, technology modernization and organizational innovation. In connection with this transition, Mr. Harding will no longer serve as the Company's Chief Accounting Officer.

On November 9, 2026, the Board of Directors (the "Board") of the Company appointed Bryan Dennis to succeed Mr. Harding as the Company's Chief Accounting Officer, effective as of the Effective Date. Mr. Dennis, age 44, has served as the Company's Senior Vice President, Finance, Corporate Controller and Treasurer since September 2022. Before joining the Company, Mr. Dennis served as Vice President and Corporate Controller at Wind River Systems from June 2019 to September 2022. Earlier in his career, Mr. Dennis served in accounting and financial reporting leadership positions at SIG Combibloc, Jive Software and Tripwire, and as a Senior Manager at KPMG. Mr. Dennis holds a bachelor's degree in business administration from the University of Portland and is an active certified public accountant in Oregon.

In connection with his appointment, Mr. Dennis will receive an annual base salary of $400,000 and will be eligible to receive an annual target cash bonus equal to 60% of his annual base salary. Mr. Dennis will also receive a grant of a promotion equity award with an approximate value of $200,000 (75% in time-based restricted stock units and 25% in performance-based stock units), vesting over three (3) years in accordance with the terms and conditions of the Company's applicable equity incentive plan and award agreements. Mr. Dennis will be eligible to participate in the Company's policy on Severance Benefits for Executive Officers and will be subject to the Company's existing Change in Control Severance Agreement applicable to executive officers, in each case in accordance with its terms.

There are no family relationships between Mr. Dennis and any director or executive officer of the Company, and Mr. Dennis is not a party to any transaction requiring disclosure under Item 404(a) of Regulation S-K.

Chief Information Officer Retirement

On November 9, 2026, Jeffrey McKibben, Chief Information Officer of the Company, notified the Company of his intention to retire from the Company. Mr. McKibben will continue to serve as Chief Information Officer until a successor is appointed or such earlier date as determined by the Board. At that time, Mr. McKibben will move to a non-officer role with the Company and provide transition services to support an orderly handover of his responsibilities. The Company has commenced a search for his successor.