SilverBox Corp IV Extends Business Combination Outside Date to Dec 31, 2026

What Happened
SilverBox Corp IV (SBXD) filed an 8-K dated August 5, 2026 disclosing a Second Amendment to its Business Combination Agreement (dated August 6, 2025) with Parataxis Holdings Inc. (the proposed public company, “PubCo”), related merger subsidiaries and Parataxis Holdings LLC (the “Company”). The Second Amendment, dated August 4, 2026, extends the agreement’s Outside Date—the deadline to complete the proposed business combination—from August 6, 2026 to December 31, 2026. The amendment also allows SBXD and the Company to further extend the Outside Date under specified written-notice terms if SBXD obtains its own extension.

Key Details

• Second Amendment dated August 4, 2026; 8-K filed August 5, 2026.
• Outside Date extended from August 6, 2026 to December 31, 2026.
• Provides a mechanism for further extension by written notice: extension length equals the shorter of (i) the period ending on the last day of SBXD’s extension and (ii) a mutually agreed period.
• PubCo and the Company have filed an S-4 registration statement (No. 333-289994) in connection with the transactions.

Why It Matters
For investors, this change formally gives the parties more time to complete the proposed merger and related transactions. The filing reiterates that closing remains subject to the conditions in the Business Combination Agreement (including shareholder approval) and highlights risks the parties listed—such as the possibility the Transactions may not close, shareholder redemptions reducing available funds, and uncertain timing for a listing of PubCo securities. In short, the amendment does not guarantee closing; it only extends the deadline and preserves the parties’ ability to seek further extensions as described.