X0202 SCHEDULE 13D/A 0001437749-26-018547 0002137030 XXXXXXXX LIVE 3 Common Stock, $0.01 par value per share 10/21/2026 false 0001389545 66987P508 Stablecoin Development Corp

222 LAKEVIEW AVE SUITE 800 WEST PALM BEACH FL 33401

David Garcia 345-749-9601 PO Box 144, 9 Forum Lane, Suite 3119 Camana Bay, George Town E9 KY 1-9006 0002137030 N Sky Frontier Foundation b WC N E9 8115087.00 0.00 8115087.00 0.00 8115087.00 Y 9.9 OO Non-U.S. Foundation This Amendment No. 3 to Schedule 13D (this "Amendment") amends and supplements the Schedule 13D filed with the Securities and Exchange Commission on May 27, 2026, as amended by Amendment No. 1 filed on July 22, 2026 and as further amended by Amendment No. 2 filed on August 21, 2026 (as so amended, the "Schedule 13D"), by Sky Frontier Foundation (the "Reporting Person"), relating to the common stock, $0.01 par value per share (the "Common Stock"), of Stablecoin Development Corp (the "Issuer"). Capitalized terms used but not defined in this Amendment have the meanings given to them in the Schedule 13D. Except as expressly amended and supplemented by this Amendment, the Schedule 13D remains in full force and effect. This Amendment is being filed to report (i) a change in the Reporting Person's beneficial ownership resulting from an increase in the number of outstanding shares of Common Stock and (ii) the appointment of the Reporting Person's nominee to the Issuer's board of directors, as described in Item 4. As reported in the Issuer's Pre-Effective Amendment No. 3 to its Registration Statement on Form S-3 (File No. 333-298229) filed on October 26, 2026 (the "Registration Statement Amendment"), 73,117,016 shares of Common Stock were outstanding as of October 21, 2026. The 10,000,000 shares of Common Stock underlying the first and second tranches of the Warrant are currently exercisable. Because the Beneficial Ownership Limitation restricts the Reporting Person from exercising the Warrant to the extent that, after giving effect to such exercise, the Reporting Person would beneficially own more than 9.99% of the outstanding Common Stock, the Reporting Person may be deemed to beneficially own 8,115,087 shares of Common Stock, representing approximately 9.99% of the outstanding Common Stock. The Reporting Person has not exercised any portion of the Warrant. Common Stock, $0.01 par value per share Stablecoin Development Corp 222 LAKEVIEW AVE SUITE 800 WEST PALM BEACH FL 33401 The Reporting Person has exercised its right under the IRA to nominate one director to the Issuer's board of directors. On September 2, 2026, the Issuer's board of directors appointed David Garcia Rios as a Class II director of the Issuer, with a term expiring at the Issuer's 2027 annual meeting of stockholders. As of October 21, 2026, the Reporting Person may be deemed to beneficially own 8,115,087 shares of Common Stock, representing approximately 9.99% of the outstanding Common Stock. The percentage is calculated based on 73,117,016 shares of Common Stock outstanding as of October 21, 2026, as reported in the Registration Statement Amendment, plus the 8,115,087 shares issuable to the Reporting Person upon exercise of the Warrant within 60 days. As of October 21, 2026, the 10,000,000 shares underlying the first and second tranches of the Warrant are exercisable. However, the Beneficial Ownership Limitation restricts the Reporting Person from exercising the Warrant to the extent that, after giving effect to such exercise, the Reporting Person would beneficially own more than 9.99% of the outstanding Common Stock. Accordingly, only 8,115,087 shares are included in the Reporting Person's beneficial ownership. The Reporting Person disclaims beneficial ownership of any shares issuable upon exercise of the Warrant in excess of the Beneficial Ownership Limitation. (i) Sole power to vote or to direct the vote: 8,115,087 (ii) Shared power to vote or to direct the vote: 0 (iii) Sole power to dispose or to direct the disposition: 8,115,087 (iv) Shared power to dispose or to direct the disposition: 0. Except as described in this Amendment, the Reporting Person has not effected any transaction in the Common Stock during the past 60 days. The change in the Reporting Person's beneficial ownership resulted solely from the increase in the number of outstanding shares of Common Stock described in this Amendment, and not from the Reporting Person's exercise of the Warrant or any acquisition or disposition of Common Stock. Not applicable. Not applicable. Sky Frontier Foundation /s/ David Garcia 10/29/2026