SilverBox Corp IV filed a Current Report on Form 8-K to disclose the execution of a Second Amendment to its Business Combination Agreement with Parataxis Holdings Inc. dated August 4, 2026. The amendment extends the Outside Date for the proposed business combination from August 6, 2026, to December 31, 2026. This extension provides flexibility for both parties to further extend the deadline if SilverBox Corp IV seeks and receives a shareholder-approved extension of its initial business combination deadline. The filing includes the Second Amendment as Exhibit 2.1. SilverBox Corp IV is a blank check company (SPAC) focused on effecting a merger, capital stock exchange, asset acquisition, or other similar business combination with one or more businesses.