Ultra Clean Holdings Inc

The information required by this item concerning directors and corporate governance is incorporated by reference to the section entitled, “Election of Directors” in our Proxy Statement for the December 27, 2024 Annual Meeting of Stockholders.

For information with respect to Executive Officers, see Part I, Item 1 of this Annual Report on Form 10-K, under “Executive Officers.”

The information required by this item with respect to Section 16(a) beneficial reporting compliance is incorporated by reference to the section entitled, “Section 16(a) Beneficial Ownership Reporting Compliance” in our Proxy Statement for the December 27, 2024 Annual Meeting of Stockholders.

We have adopted a Code of Business Conduct and Ethics that is designed to qualify as a “code of ethics” within the meaning of Section 406 of the Sarbanes-Oxley Act of 2002 and the rules promulgated thereunder. This code of ethics is available on our website atwww.uct.com. To the extent required by law, any amendments to, or waivers from, any provision of the code of ethics will be promptly disclosed to the public. To the extent permitted by such legal requirements, we intend to make such public disclosure by posting the relative material on our website in accordance with SEC rules.

Insider Trading Policies and Procedures

We have adopted insider trading policies and procedures governing the purchase, sale and other dispositions of our securities by directors, officers and employees that are designed to promote compliance with insider trading laws, rules and regulations, and applicable NASDAQ listing standards, as well as procedures designed to further the foregoing purposes. A copy of our insider trading policy is filed with this Annual Report on Form 10-K as Exhibit 19.1.