SCHEDULE 13D/A 0002052113 XXXXXXXX LIVE 1 Class A common stock, par value $0.01 per share 09/05/2025 false 0001784254 58450D104 MediaCo Holding Inc.

48 WEST 25TH STREET, THIRD FLOOR NEW YORK NY 10010

Joseph Virgilio (212) 810-5800 BlackRock, Inc. 50 Hudson Yards New York NY 10001 0002052113 N BlackRock Portfolio Management LLC b OO N DE 35257476.00 0.00 35257476.00 0.00 35257476.00 N 46.1 HC Class A common stock, par value $0.01 per share MediaCo Holding Inc. 48 WEST 25TH STREET, THIRD FLOOR NEW YORK NY 10010 Explanatory Note This Amendment No. 1 to the Schedule 13D amends and supplements the statement on Schedule 13D for BlackRock Portfolio Management LLC ("BPM"), an indirectly wholly owned subsidiary of BlackRock, Inc. ("BlackRock"), originally filed with the Securities and Exchange Commission (the "SEC") on July 3, 2025 (as amended, the "Schedule 13D"). Capitalized terms used in this Schedule 13D and not otherwise defined have the meanings set forth in the Schedule 13D. The responses of BPM to Rows (11) and (13) of the cover page of this Schedule 13D are incorporated herein by reference. None of the Covered Persons beneficially owns any shares of Class A Common Stock. The aggregate percentages of shares of Class A Common Stock reported as beneficially owned by the Reporting Business Units were calculated based on 48,264,309 shares of Class A Common Stock issued and outstanding as of August 1, 2025, as disclosed in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 14, 2025, plus 28,205,938 shares of Class A Common Stock issued upon exercise of the Warrant. The responses of BPM to Rows (7) through (10) of the cover page of this Schedule 13D are incorporated herein by reference. The Reporting Business Units engaged in the following transaction in the Issuer's Class A Common Stock in the 60-day period ended September 5, 2025: on September 5, 2025, Aggregator exercised the Warrant to purchase 28,206,152 Warrant Shares and paid the exercise price on a cashless basis, resulting in the Issuer withholding 214 of the Warrant Shares to pay the exercise price and issuing to Aggregator the remaining 28,205,938 Warrant Shares. Except for investment advisory clients of the Reporting Business Units, who may have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, Class A Common Stock, no other person is known by BPM to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, any Class A Common Stock that may be beneficially owned by the Reporting Business Units. Not applicable. The information in Item 6 of the Schedule 13D is hereby amended and supplemented as follows: On September 5, 2025, Aggregator exercised the Warrant to purchase 28,206,152 Warrant Shares and paid the exercise price on a cashless basis, resulting in the Issuer withholding 214 of the Warrant Shares to pay the exercise price and issuing to Aggregator the remaining 28,205,938 Warrant Shares. As a result, Aggregator is now the stockholder with respect to those Warrant Shares. Except as set forth in this Schedule 13D, there are no contracts, arrangements, understandings or relationships between BPM and any other person with respect to any securities of the Issuer or among the Reporting Business Units, including but not limited to transfer or voting of any securities of the Issuer, finder's fees, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving or withholding of proxies (other than the transfer of voting rights with respect to the shares of Class A Common Stock that are loaned out in the ordinary course of certain Reporting Business Units' securities lending programs). BlackRock Portfolio Management LLC /s/ Joseph Virgilio 09/08/2025