Ultra Clean Holdings, Inc.

6. INCOME TAX

The Company recorded income tax provisions of $8.7 million and $9.9 million for the three months ended September 26, 2025 and September 27, 2024, respectively, and $23.3 million and $28.2 million for the nine months ended September 26, 2025 and September 27, 2024, respectively.

The Company’s effective tax rate was 1450.0% and 97.1% for the three months ended September 26, 2025 and September 27, 2024, respectively, and (15.8)% and 66.0% for the nine months ended September 26, 2025 and September 27, 2024, respectively.

The change in respective tax rates reflects, primarily, the goodwill impairment booked in the second quarter of fiscal year 2025, changes in the geographic mix of worldwide earnings and financial results in jurisdictions which are taxed at different rates and the impact of losses in jurisdictions with full valuation allowances on deferred tax assets. Company management continuously evaluates the need for a valuation allowance and, as of September 26, 2025, concluded that a full valuation allowance on its U.S. federal and state and certain of its foreign deferred tax assets was still appropriate.

As of September 26, 2025 and December 27, 2024, the Company’s gross liability for unrecognized tax benefits, excluding interest, was $5.2 million and $2.3 million, respectively. Increases or decreases to interest and penalties on uncertain tax positions are included in the income tax provision in the Condensed Consolidated Statements of Operations. Although it is possible that some of the unrecognized tax benefits could be settled within the next twelve months, the Company cannot reasonably estimate the outcome at this time.

The Organization for Economic Co-operation and Development and the G20 Inclusive Framework on Base Erosion and Profit Shifting (the “Inclusive Framework”) have put forth Pillar Two proposals that ensure a minimal level of taxation. Several countries in which the Company operates have adopted legislation to implement the Inclusive Framework’s global corporate minimum tax rate of fifteen percent. This legislation became effective in certain jurisdictions the Company operates in for the current fiscal year ending December 26, 2025. Based on the Company’s current analysis of the enacted Pillar Two provisions and transitional safe harbor provisions, Pillar Two will not have a significant impact on the Company's financial statements for fiscal year 2025.

On July 4, 2025, the reconciliation bill, commonly referred to as the One Big Beautiful Bill Act (“OBBBA”), was signed into law, enacting significant changes to U.S. tax and related laws. Some of the provisions of the new tax law affecting corporations include, but are not limited to, expensing of domestic research expenses, increasing the limit of the deduction

• 16 - of interest expense deduction to thirty percent of EBITDA, and one hundred percent bonus depreciation on eligible property acquired after January 19, 2025. The legislation has multiple effective dates, with certain provisions effective in 2025 and others implemented through 2027. The impacts of the OBBBA are reflected in the Company’s results for the three months ended September 26, 2025, and there was no material impact to our income tax expense.