DIGITAL MANUFACTURING. REIMAGINED.

Disclaimer 然 Disclaimer This presentation (this "presentation") is provided for informational purposes and has been prepared to assist interested parties in making their own evaluation with respect to a potential business combination between Fathom Holdco, LLC ("Fathom") and Altimar Acquisition Corp. II ("Altimar II") and for no other purpose. This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any sale of any securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to a registration or qualification under the securities laws of such other jurisdiction. No Representations and Warranties This presentation is for informational purposes only and does not purport to contain all of the information that may be required to evaluate a possible investment decision with respect to Altimar II. This presentation is not intended to form the basis of any investment decision by the recipient and does not constitute investment, tax or legal advice. No representation or warranty, express or implied, is or will be given by Altimar II or Fathom or any of their respective affiliates, directors, officers, employees or advisers or any other person as to the accuracy or completeness of the information in this presentation or any other written, oral or other communications transmitted or otherwise made available to any party in the course of its evaluation of a possible transaction between Altimar II and Fathom or a possible investment in Fathom and no responsibility or liability whatsoever is accepted for the accuracy or sufficiency thereof or for any errors, omissions or misstatements, negligent or otherwise, relating thereto. The information contained in this presentation is preliminary in nature and is subject to change, and any such changes may be material. Altimar II and Fathom disclaim any duty to update the information contained in this presentation. Forward-Looking Statements This presentation includes "forward-looking statements" within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Altimar II's and Fathom's actual results may differ from their expectations, estimates and projections and consequently, you should not rely on these forward-looking statements as predictions of future events. Words such as "expect", "estimate", "project", "budget", "forecast", "plan," "target," "goal," "anticipate", "intend", "plan", "may", "will", "could", "should", "believes", "predicts", "potential", "continue", and similar expressions are intended to identify such forward-looking statements. These forward-looking statements include, without limitation, Altimar II's and Fathom's expectations with respect to future performance and anticipated financial impacts of the Transaction, the satisfaction of closing conditions to the Transaction and the timing of the completion of the Transaction. These forward-looking statements involve significant risks and uncertainties that could cause the actual results to differ materially from the expected results. You should carefully consider the risks and uncertainties described in the "Risk Factors" section of Altimar II's registration statement on Form S-1 and Reports under the Securities Exchange Act previously filed with the Securities and Exchange Commission (the "SEC"). In addition, there will be risks and uncertainties described in the proxy statement/prospectus on Form S-4 relating to the proposed business combination, which is expected to be filed by Altimar II with the SEC, and other documents filed by Altimar II from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Most of these factors are outside Altimar II's and Fathom's control and are difficult to predict. Factors that may cause such differences include, but are not limited to: (1) the outcome of any legal proceedings that may be instituted against Altimar II or Fathom following the announcement of the Transaction; (2) the inability to complete the Transaction, including due to the inability to concurrently close the proposed business combination and the private placement of Altimar II securities or due to failure to obtain approval of the stockholders of Altimar II; (3) delays in obtaining, adverse conditions contained in, or the inability to obtain necessary regulatory approvals or complete regulatory reviews required to complete the Transaction; (4) the risk that the Transaction disrupts current plans and operations as a result of the announcement and consummation of the Transaction; (5) the inability to recognize the anticipated benefits of the Transaction, which may be affected by, among other things, competition, the ability of the combined company to grow and manage growth profitably, maintain relationships with customers and suppliers and retain its key employees; (6) costs related to the Transaction; (7) changes in the applicable laws or regulations; (8) the possibility that the combined company may be adversely affected by other economic, business, and/or competitive factors; (9) the continuing impact of the global COVID-19 pandemic; and (10) other risks and uncertainties indicated from time to time described in Altimar II's registration on Form S-1, including those under "Risk Factors" therein, and in Altimar II's other filings with the SEC. Altimar II and Fathom caution that the foregoing list of factors is not exclusive and not to place undue reliance upon any forward-looking statements, including projections, which speak only as of the date made. Neither Altimar II nor Fathom undertakes or accepts any obligation to provide any updates or revisions to any forward-looking statements to reflect any changes in its expectations or any change in events, conditions or circumstances on which any such statement is based. Financial Information This presentation includes references to financial measures that are calculated and presented on the basis of methodologies other than in accordance with generally accepted accounting principles in the United States of America ("GAAP"). Any non-GAAP financial measures used in this presentation are in addition to, and should not be considered superior to, or a substitute for, financial statements prepared in accordance with GAAP. Non-GAAP financial measures should not be considered in isolation and are subject to significant inherent limitations. The non-GAAP measures presented herein may not be comparable to similar non-GAAP measures presented by other companies. Fathom believes that these non-GAAP measures of financial results provide useful information to management and investors regarding certain financial and business trends relating to Fathom's financial condition and results of operations. Fathom believes that the use of these non-GAAP financial measures provides an additional tool for investors to use in evaluating ongoing operating results and trends and in comparing Fathom's financial measures with other similar companies, many of which present similar non-GAAP financial measures to investors. These non-GAAP financial measures are subject to inherent limitations as they reflect the exercise of judgments by management about which expense and income are excluded or included in determining these non-GAAP financial measures. Financial information and data of Fathom for 2020 and 2021 in this presentation are unaudited and reflect various adjustments to give pro forma effect to acquisitions completed by Fathom through April 30, 2021 as if such transactions occurred on January 1, 2020. This unaudited, adjusted financial information and data are for illustrative and informational purposes only and are not necessarily indicative of the operating or financial results that would have occurred if the acquisitions had been completed as of such date. This unaudited, adjusted financial information and data as well as the other financial information and data included in this presentation does not conform to SEC Regulation S-X or Public Company Accounting Oversight Board (PCAOB) standards. Accordingly, such information may not be included in, may be adjusted or may be presented differently in any proxy statement/prospectus to be filed with the SEC. FATHOM 2 Fathom Proprietary and Confidential