Ultra Clean Holdings Inc

7. INCOME TAX

The Company's effective tax rate was 97.1% and (70.7)% for the three months ended September 27, 2024 and September 29, 2023, respectively, and 66.0% and (488.6)% for the nine months ended September 27, 2024 and September 29, 2023, respectively. The Company’s income tax provision was $9.9 million and $5.3 million for the three months ended September 27, 2024 and September 29, 2023, respectively, and $28.2 million and $17.1 million for the nine months ended September 27, 2024 and September 29, 2023, respectively. The change in respective tax rates reflects, primarily, 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 27, 2024, 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 27, 2024 and September 29, 2023, the Company’s gross liability for unrecognized tax benefits, excluding interest, was $3.1 million and $2.7 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.