Ultra Clean Holdings, Inc.

13. NET LOSS PER SHARE

Basic net loss per share is computed by dividing net loss by the weighted-average number of outstanding shares of common stock during the period. Diluted net loss per share is computed using the treasury stock method for stock-based awards, and the if-converted method for convertible notes. Under the treasury stock method, the denominator is adjusted to include, when dilutive, incremental shares issuable upon the assumed exercise of stock options, ESPP shares to be issued, and vesting of service-based and performance-based restricted stock units. Under the if-converted method, the numerator is adjusted to add back interest expense on the convertible notes, net of tax, and the denominator is adjusted to include

• 20 - incremental shares issuable upon conversion of the convertible notes, when the effect of applying this method is dilutive. The Company has a single class of common stock. The computation of basic and diluted net loss per share is as follows:

Potential common shares from employee stock plans totaling 1.5 million and 0.3 million for the three months ended March 27, 2026 and March 28, 2025, respectively, as well as approximately 7.1 million shares issuable upon conversion of the Company’s convertible notes, were excluded from the computation of diluted loss per share because their effect would have been antidilutive due to the net loss incurred in those periods.