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Exhibit 99.1 Press Release Ultra Clean Reports Second Quarter 2021 Financial Results Source : Ultra Clean Holdings , Inc. HAYWARD , Calif . , August 2 , 2021 / PRNewswire / Ultra Clean Holdings , Inc. ( Nasdaq : UCTT ) , today reported its financial results for the second quarter ended June 25 , 2021 . " UCT delivered strong second quarter results driven by disciplined execution in a robust demand environment across all of our end markets , " said Jim Scholhamer , CEO . " These results demonstrate that UCT's diversified suite of capabilities and ability to deliver are enabling us to play a larger , more valuable role in the semiconductor ecosystem " . Second Quarter 2021 GAAP Financial Results Total revenue was $ 515.2 million . Products contributed $ 442.5 million and Services added $ 72.7 million . Total gross margin was 19.4 % , operating margin was 6.2 % , and net income was $ 17.1 million or $ 0.39 per basic and diluted share . This compares to total revenue of $ 417.6 million , gross margin of 20.8 % , operating margin of 9.7 % , and net income of $ 25.0 million or $ 0.62 and $ 0.60 per basic and diluted share in the prior quarter . Second Quarter 2021 Non - GAAP Financial Results On a non - GAAP basis , gross margin was 21.2 % , operating margin was 11.7 % , and net income was $ 43.7 million or $ 0.99 per diluted share . This compares to gross margin of 21.3 % , operating margin of 12.2 % , and net income of $ 38.2 million or $ 0.92 per diluted share in the prior quarter . Third Quarter 2021 Outlook The Company expects revenue in the range of $ 520.0 million to $ 560.0 million and GAAP diluted net income per share to be between $ 0.68 and $ 0.85 . The Company expects non - GAAP diluted net income per share to be between $ 0.94 and $ 1.10 . Conference Call The call will take place on Monday August 2 , 2021 at 1:30 p.m. PT ( 4:30 pm ET ) and can be accessed by dialing 1-844-826-3034 or 1-412-317- 5179. No passcode is required . A replay of the call will be available by dialing 1-877-344-7529 or 1-412-317-0088 and entering the confirmation code 10158101. The Webcast will be available on the Investor Relations section of the Company's website at http://uct.com/investors/events/ . About Ultra Clean Holdings , Inc. Ultra Clean Holdings , Inc. is a leading developer and supplier of critical subsystems , components and parts , and ultra - high purity cleaning and analytical services primarily for the semiconductor industry . Under its Products division , UCT offers its customers an integrated outsourced solution for major subassemblies , improved design - to - delivery cycle times , design for manufacturability , prototyping , and high - precision manufacturing . Under its Services Division , UCT offers its customers tool chamber parts cleaning and coating , as well as micro - contamination analytical services . Ultra Clean is headquartered in Hayward , California . Additional information is available at www.uct.com . Use of Non - GAAP Measures In addition to providing results that are determined in accordance with Generally Accepted Accounting Principles in the United States of America ( GAAP ) , management uses non - GAAP gross margin , non - GAAP operating margin and non - GAAP net income to evaluate the Company's operating and financial results . We believe the presentation of non - GAAP results is useful to investors for analyzing our core business and business trends and comparing performance to prior periods , along with enhancing investors ' ability to view the Company's results from management's perspective . The presentation of this additional information should not be considered a substitute for results prepared in accordance with GAAP . Tables presenting reconciliations from GAAP results to non - GAAP results are included at the end of this press release .