Filed Pursuant to Rule 424(b)(3)

Registration No. 333-251653

PROSPECTUS SUPPLEMENT

Desktop Metal, Inc.

192,707,982 Shares of Class A Common Stock

25,010,494 Shares of Class A Common Stock Issuable Upon Exercise of Warrants

This prospectus supplement further supplements and updates the prospectus dated June 3, 2021, relating to the resale of up to 192,707,982 shares of our Class A common stock by the selling securityholders named in the prospectus (including their pledgees, donees, transferees or other successors-in-interest) and the issuance by us of up to 25,010,494 shares of Class A common stock upon the exercise of warrants, or the Final Prospectus.

This prospectus supplement incorporates into the Final Prospectus the information (other than information that is furnished and not deemed filed) contained in the attached:

Our Class A common stock is listed on the New York Stock Exchange, or the NYSE, under the symbol “DM”. On November 8, 2021, the closing sale price of our Class A common stock as reported on the NYSE was $9.20.

We are an “emerging growth company” under applicable Securities and Exchange Commission rules and, as such, have elected to comply with certain reduced public company disclosure requirements for our filings with the Securities and Exchange Commission.

Our business and investment in our Class A common stock involve significant risks. These risks are described in the section titled “Risk Factors” in our Quarterly Report on Form 10-Q filed on August 11, 2021.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

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The date of this prospectus supplement is November 9, 2021.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 4, 2021

Desktop Metal, Inc.

(Exact name of registrant as specified in its charter)

(978) 224-1244

Registrant’s telephone number, including area code

N/A

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

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. ¨

Item 8.01. Other Events.

On November 4, 2021, the Audit Committee of the Board of Directors of Desktop Metal, Inc. (the “Company”) engaged a third party to conduct an independent internal investigation as a result of a whistleblower complaint relating to, among other matters, manufacturing and product compliance practices and procedures with respect to a subset of its photopolymer equipment and materials at its EnvisionTec US LLC facility in Dearborn, Michigan. While the investigation remains on-going, the Company has taken initial actions, including implementing changes in the management of and procedures associated with manufacturing the applicable products. Based on the investigation to date, the Company does not believe the matters involved will have a material impact on the Company, its financial statements or its business.

Additional Information and Where to Find It

This communication relates to a proposed business combination transaction between Desktop Metal and ExOne. In connection with the proposed transaction, Desktop Metal filed a registration statement on Form S-4 with the Securities and Exchange Commission (the “SEC”), includes a proxy statement of ExOne and a prospectus with respect to shares of Desktop Metal’s common stock to be issued in the proposed transaction (the “proxy statement/prospectus”). INVESTORS AND SECURITY HOLDERS OF DESKTOP METAL AND EXONE ARE URGED TO READ THE REGISTRATION STATEMENT AND ANY OTHER RELEVANT DOCUMENTS THAT ARE OR WILL BE FILED WITH THE SEC, INCLUDING THE PROXY STATEMENT/PROSPECTUS, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS WHEN THEY BECOME AVAILABLE, BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND RELATED MATTERS. Beginning on October 12, 2021, ExOne mailed the proxy statement/prospectus to its stockholders in connection with meeting to be held to request approval of the proposed transaction. Investors and security holders will be able to obtain the documents free of charge at the SEC’s website, www.sec.gov, from Desktop Metal at its website, ir.desktopmetal.com, or from ExOne at its website, investor.exone.com.

No Offer or Solicitation

This communication is not intended to and shall not constitute an offer to buy or sell or the solicitation of an offer to buy or sell any securities, or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Participants in the Solicitation

Desktop Metal, ExOne and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information concerning Desktop Metal’s participants is set forth in the proxy statement, filed June 17, 2021, for Desktop Metal’s 2021 annual meeting of stockholders as filed with the SEC on Schedule 14A and on certain of its Current Reports on Form 8-K. Information concerning ExOne’s participants is set forth in the proxy statement, filed April 1, 2021, for ExOne’s 2021 annual meeting of stockholders as filed with the SEC on Schedule 14A and on certain of its Current Reports on Form 8-K. Additional information regarding the interests of such participants in the solicitation of proxies, including direct and indirect interests, in respect of the proposed transaction is included in the registration statement and proxy statement/prospectus and other relevant materials filed with the SEC.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 5, 2021

Desktop Metal, Inc.

(Exact name of registrant as specified in its charter)

(978) 224-1244

Registrant’s telephone number, including area code

N/A

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company x

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. ¨

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Resignation of Director

On November 5, 2021, Ali El Siblani notified Desktop Metal, Inc. (together with its subsidiaries, the “Company”) of his intent to resign as a member of the Company’s Board of Directors and as an employee of the Company in his role as Chief Executive Officer of EnvisionTec US LLC. The decision of Mr. Siblani was not the result of any disagreement relating to the Company’s operations, policies or practices.

Additional Information and Where to Find It

This communication relates to a proposed business combination transaction between Desktop Metal and ExOne. In connection with the proposed transaction, Desktop Metal filed a registration statement on Form S-4 with the Securities and Exchange Commission (the “SEC”), includes a proxy statement of ExOne and a prospectus with respect to shares of Desktop Metal’s common stock to be issued in the proposed transaction (the “proxy statement/prospectus”). INVESTORS AND SECURITY HOLDERS OF DESKTOP METAL AND EXONE ARE URGED TO READ THE REGISTRATION STATEMENT AND ANY OTHER RELEVANT DOCUMENTS THAT ARE OR WILL BE FILED WITH THE SEC, INCLUDING THE PROXY STATEMENT/PROSPECTUS, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS WHEN THEY BECOME AVAILABLE, BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND RELATED MATTERS. Beginning on October 12, 2021, ExOne mailed the proxy statement/prospectus to its stockholders in connection with meeting to be held to request approval of the proposed transaction. Investors and security holders will be able to obtain the documents free of charge at the SEC’s website, www.sec.gov, from Desktop Metal at its website, ir.desktopmetal.com, or from ExOne at its website, investor.exone.com.

No Offer or Solicitation

This communication is not intended to and shall not constitute an offer to buy or sell or the solicitation of an offer to buy or sell any securities, or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Participants in the Solicitation

Desktop Metal, ExOne and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information concerning Desktop Metal’s participants is set forth in the proxy statement, filed June 17, 2021, for Desktop Metal’s 2021 annual meeting of stockholders as filed with the SEC on Schedule 14A and on certain of its Current Reports on Form 8-K. Information concerning ExOne’s participants is set forth in the proxy statement, filed April 1, 2021, for ExOne’s 2021 annual meeting of stockholders as filed with the SEC on Schedule 14A and on certain of its Current Reports on Form 8-K. Additional information regarding the interests of such participants in the solicitation of proxies, including direct and indirect interests, in respect of the proposed transaction is included in the registration statement and proxy statement/prospectus and other relevant materials filed with the SEC.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.