Filed Pursuant to Rule 424(b)(3)

Registration No. 333-262194

AMENDMENT NO. 1 DATED AUGUST 18, 2022

to Prospectus Supplement No. 2 dated August 16, 2022

(to prospectus dated May 2, 2022)

FATHOM DIGITAL MANUFACTURING CORPORATION

45,423,250 SHARES OF CLASS A COMMON STOCK

9,900,000 WARRANTS TO PURCHASE SHARES OF CLASS A COMMON STOCK

18,525,000 SHARES OF CLASS A COMMON STOCK UNDERLYING WARRANTS TO

PURCHASE CLASS A COMMON STOCK AND

90,570,234 SHARES OF CLASS A COMMON STOCK UNDERLYING CLASS B COMMON STOCK

This Amendment No. 1 to Prospectus Supplement No. 2 is being filed as an update and supplement to the prospectus dated May 2, 2022, as supplemented by Prospectus Supplement No. 1, dated May 17, 2022 and Prospectus Supplement No. 2, dated August 16, 2022 (and as may be further supplemented or amended from time to time, the “Prospectus”) with the information contained in our Quarterly Report on Form 10-Q, which we filed with the SEC on August 15, 2022 (the “Quarterly Report”) which was inadvertently omitted from Prospectus Supplement No. 2 thereto filed on August 16, 2022. This amendment should be read in conjunction with the Prospectus. Accordingly, we have attached the Quarterly Report to this prospectus supplement. Capitalized terms used but not defined in this prospectus supplement have the meanings given to such terms in the Prospectus.

The Prospectus and this prospectus supplement relate to the resale from time to time by the selling stockholders named in the Prospectus or their permitted transferees (collectively, the “Selling Stockholders”) of: (i) up to 36,661,014 shares of Class A common stock, par value $0.0001 per share (the “Class A common stock”) issued to the Legacy Fathom Owners in connection with the closing of the Business Combination, (ii) up to 4,770,000 shares of Class A common stock held by Altimar Sponsor II, LLC (“Sponsor”) and the other Altimar II Founders following the closing of the Business Combination, (iii) up to 2,724,736 Earnout Shares issued to certain Legacy Fathom Owners, and (iv) up to 1,267,500 Sponsor Earnout Shares. The Prospectus and this prospectus supplement also relate to (a) the resale of up to 9,900,000 Private Placement Warrants to purchase shares of Class A common stock held by Sponsor, (b) the issuance of up to 18,525,000 shares of Class A common stock upon the exercise of outstanding Public Warrants and Private Placement Warrants to purchase shares of Class A common stock, and (c) the issuance of up to 90,570,234 shares of Class A common stock issuable upon the exchange of New Fathom Units (together with a corresponding number of shares of Class B common stock) held by certain of the Selling Stockholders (including 6,275,264 Earnout Shares presently represented in the form of unvested New Fathom Units).

This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.

Our Class A common stock is traded on the New York Stock Exchange (the “NYSE”) under the symbol “FATH.” On August 17, 2022, the closing price of our Class A common stock was $3.84 per share. Our Public Warrants are currently listed on the NYSE and trade under the symbol “FATH.WS.” On August 15, 2022, the closing price of our Public Warrants was $0.30 per Public Warrant.

Investing in our securities involves risks that are described in the “Risk Factors” section beginning on page 17 of the Prospectus. Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued under the Prospectus or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is August 18, 2022.

ROC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

For the quarterly period ended June 30, 2022

OR

For the transition period from to

Commission File Number: 001-39994

Fathom Digital Manufacturing Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (262) 367-8254

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of August 12, 2022, there were 61,596,519 shares of the registrant's Class A common stock outstanding and 74,014,640 shares of the registrant's vote-only, non-economic Class B common stock outstanding.

Table of Contents

EXPLANATORY NOTE

This Quarterly Report on Form 10-Q includes information pertaining to periods prior to the closing of the Business Combination (as defined in "Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations" of this Quarterly Report). Refer to Note 1 “Nature of Business” and Note 2 "Basis of Presentation" of the notes to our consolidated financial statements contained in this Quarterly Report for further information regarding the basis of presentation.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

Certain statements made in this Quarterly Report on Form 10-Q are “forward looking statements.” Statements regarding our expectations regarding the business are “forward looking statements.” In addition, words such as “estimates,” “projected,” “expects,” “estimated,” “anticipates,” “forecasts,” “plans,” “intends,” “believes,” “seeks,” “may,” “will,” “would,” “future,” “propose,” “target,” “goal,” “objective,” “outlook” and variations of these words or similar expressions (or the negative versions of such words or expressions) are intended to identify forward-looking statements. The forward-looking statements contained in this Quarterly Report on Form 10-Q and in our other periodic filings are not guarantees of future performance, conditions or results and are based on our current expectations and beliefs concerning future developments and their potential effects on us. There can be no assurance that future developments affecting us will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described under "Risk Factor Summary", “Item 1A. Risk Factors”, and "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021 (the "2021 Form 10-K"). Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. We may face additional risks and uncertainties that are not presently known to us, or that we deem to be immaterial, which may also impair our business, financial condition or prospects. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

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PART I—FINANCIAL INFORMATION

Item 1. Financial Statements.

Fathom Digital Manufacturing Corporation

Consolidated Balance Sheets

(In thousands, except share and unit amounts)

(1) Inclusive of allowance for doubtful accounts of $1,208 and $1,150 as of June 30, 2022 and December 31, 2021, respectively

(2) Inclusive of accounts payable to related parties of $443 and $1,246 as of June 30, 2022 and December 31, 2021, respectively

The accompanying notes are an integral part of these unaudited consolidated financial statements.

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Fathom Digital Manufacturing Corporation

Consolidated Statements of Comprehensive Income (Loss) (Unaudited)

(In thousands, except units, shares, per unit, and per share amounts)

The accompanying notes are an integral part of these unaudited consolidated financial statements.

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Fathom Digital Manufacturing Corporation

Consolidated Statement of Shareholders' Equity and Redeemable Non-Controlling Interest (Successor)

(Unaudited)

(In thousands, except share amounts)

The accompanying notes are an integral part of these unaudited consolidated financial statements.

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Fathom Digital Manufacturing Corporation

Consolidated Statement of Class A Contingently Redeemable Preferred Units and Members' Equity (Predecessor) (Unaudited)

(In thousands, except unit amounts)

The accompanying notes are an integral part of these unaudited consolidated financial statements.

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Fathom Digital Manufacturing Corporation

Consolidated Statements of Cash Flows (Unaudited)

(In thousands)