Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following paragraphs: As disclosed on the Issuer's Current Report on Form 8-K, filed with the SEC on August 14, 2025, on August 14, 2024, HFM, for which Mr. Hendricks, the Chairman of the board of directors of the Issuer, serves as president and a manager, completed an underwritten secondary offering of the Common Stock of the Issuer (the "Offering"). Pursuant to the terms and conditions of the Underwriting Agreement, dated August 12, 2025 (the "Underwriting Agreement"), by and among the Issuer, HFM and Needham & Company, LLC, as representatives of the several underwriters named therein (the "Underwriters"), HFM sold 8,050,000 shares of Common Stock (including 1,050,000 shares of Common Stock sold in connection with the Underwriters' option to purchase additional shares) at a price per share of $3.50. In connection with the transaction, HFM and Mr. Hendricks, each agreed that, subject to specified exceptions, for a period of ninety (90) days from the date of the final prospectus supplement (the "Lock-Up Period"), without the prior written consent of the underwriters, they will not (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock beneficially owned or any other securities so owned convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any hedging, swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock or any security convertible into or exercisable or exchangeable for Common Stock, (iii) make any demand for, or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the Underwriting Agreement, which is filed as Exhibit 99.1 hereto and which is incorporated herein by reference.

Item 5 of the Schedule 13D is hereby amended and restated in its entirety as follows: The aggregate number and percentage of Common Stock beneficially owned by each Reporting Person and the number of shares as to which there is sole power to vote or to direct the vote, shared power to vote or to direct the vote, sole power to dispose or to direct the disposition, or shared power to dispose or to direct the disposition are set forth on rows 7 through 11 and row 13 of the cover pages of this Amendment No. 54 and are hereby incorporated herein by reference. The aggregate percentage of shares reported owned by each Reporting Person is based upon 57,929,733 shares outstanding as of August 4, 2025, based on information reported by the Issuer.

As of the date hereof, HFM directly holds 12,206,188 shares of Common Stock, and is controlled by its manager, John Hendricks. As of the date hereof, John Hendricks directly holds 395,357 shares of Common Stock.

Other than as set forth above, HFM has not effected any transactions in the Common Stock during the 60 days prior to the filing of this Amendment No. 5. Mr. Hendricks has not effected any transactions in the Common Stock in 60 days prior to the filing of this Amendment No. 5.

To the best knowledge of the Reporting Persons, no one other than the Reporting Persons, or the partners, members, affiliates or shareholders of the Reporting Persons, has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Stock reported herein as beneficially owned by the Reporting Persons.

Item 6 of the Schedule 13D is hereby amended and supplemented as follows: Item 4 above summarizes certain provisions of the Underwriting Agreement and is incorporated herein by reference. A copy of the Underwriting Agreement is attached as an exhibit hereto and incorporated herein by reference.

99.1 Underwriting Agreement, dated August 12, 2025, among CuriosityStream Inc., Hendricks Factual Media LLC and Needham & Company, LLC, as representatives to the several underwriters named therein (incorporated by reference to Exhibit 1.1 to the Issuer's Current Report on Form 8-K filed with the SEC on August 14, 2025).