直接数字控股有限公司-美国股票招股说明书(2025-09-12版)

8,500,000 Shares of Class A Common Stock This prospectus supplement updates and supplements the prospectus dated January 28, 2025 (as may be further supplemented or amendedfrom time to time, the “Prospectus”), which forms part of our Registration Statement on Form S-1 (File No. 333-284344). This prospectus supplement is being filed to update and supplement the Prospectus with the information contained in our Quarterly Reporton Form 10-Q for the period ended June 30, 2025, filed with the U.S. Securities and Exchange Commission on August 6, 2025 (the“Quarterly Report”). Accordingly, we have attached the Quarterly Report to this prospectus supplement. This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not bedelivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectussupplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectusand this prospectus supplement, you should rely on the information in this prospectus supplement. We are a “smaller reporting company” and an “emerging growth company” under the federal securities laws and, as such, are subject toreduced public company reporting requirements. See “Implications of Being an Emerging Growth Company and a Smaller ReportingCompany” in the Prospectus. Our shares of Class A common stock, par value $0.001 per share (the “Class A Common Stock”), are listed on the Nasdaq Capital Marketunder the symbol “DRCT.” On September 11, 2025, the closing sale price of our Class A Common Stock was $0.41 per share. Investing in our securities involves a high degree of risk. You should read “Risk Factors” beginning on page11of the Prospectus,page 13 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and page 40 of the Quarterly Report toread about factors to consider before purchasing our securities. Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesecurities to be issued under this prospectus or determined if this prospectus is truthful or complete. Any representation to thecontrary is a criminal offense. The date of this prospectus supplement is September 12, 2025. UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549 QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED JUNE 30, 2025OR DIRECT DIGITAL HOLDINGS, INC.(Exact name of registrant as specified in its charter) (832) 402-1051(Registrant’s telephone number, including area code) 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 thepreceding 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.YesxNoo Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to besubmitted and posted 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 wasrequired to submit and post such files). YesxNoo 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 emerginggrowth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of theExchange Act. (Check one): 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 revisedfinancial accounting standards provided pursuant to Section 13(a) of the Exchange Act .o Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YesoNox As of August4, 2025, there were 12,069,388 shares of the registrant’s Class A Common Stock outstanding, par value $0.001 per share, and 10,448,000 shares of theregistrant’s Class B Common Stock outstanding, par value $0.001 per share. TABLE OF CONTENTS ITEMPart I. Financial Information31.FINANCIAL STATEMENTS (UNAUDITED)Condensed Consolidated Balance Sheets as ofJune30, 2025andDecember31, 20243Condensed Consolidated Statements of Operations for theThree and Six Months EndedJune30, 2025and20244Condensed Consolidated Statements of Changes in Stockholders’ Deficit for theThree and Six MonthsEndedJune30, 2025and20245Condensed Consolidated Statements of Cash Flows for theSix Months EndedJune30, 2025and20246Notes to Condensed Consolidated Financial Statements72.Management’s Discussion and Analysis of Financial