SilverBox Corp IV (SBXD) files a range of documents with the U.S. Securities and Exchange Commission (SEC) that detail its activities as a New York Stock Exchange-listed special purpose acquisition company (SPAC). On this page, investors can review SBXD’s SEC filings, including current reports on Form 8-K that describe material events connected to its proposed business combination with Parataxis Holdings LLC and Parataxis Holdings Inc. (Pubco).
The company’s Form 8-K filings outline key steps in the transaction process, such as the execution and amendment of the Business Combination Agreement, the filing of the Registration Statement on Form S-4 that includes a preliminary proxy statement and prospectus, and changes to preferred equity subscription agreements related to Bitcoin purchases by Parataxis Holdings. Other 8-K reports address governance matters, including director resignations and appointments and committee assignments.
For a SPAC like SilverBox Corp IV, investors often focus on filings that explain the structure and consideration of the business combination, the treatment of public shares and warrants, and the conditions that must be satisfied before closing. The Registration Statement on Form S-4, referenced repeatedly in SBXD’s 8-Ks, is central to understanding the proposed mergers that will result in SilverBox Corp IV and Parataxis Holdings LLC becoming wholly owned subsidiaries of Pubco.
Stock Titan’s platform provides access to these SEC filings with AI-powered summaries that help explain complex transaction terms and risk disclosures in clearer language. Users can quickly see the main points of lengthy documents such as Form 8-Ks and the S-4 Registration Statement, while still being able to open the full text for detailed review. Real-time updates from EDGAR ensure that new filings, including any future proxy materials or additional current reports, are available as soon as they are posted, supporting investors who monitor SBXD’s progress toward its initial business combination.
W. R. Berkley Corporation filed an amendment (Schedule 13G/A) reporting beneficial ownership of 1,514,573 Class A Ordinary Shares of SilverBox Corp. The filing lists this holding as 7.4% of the class and shows shared voting and shared dispositive power over 1,514,573 shares. The filing is signed by Richard M. Baio on 05/07/2026.
SilverBox Corp IV and the counterparties to its business combination agreement amended that agreement on May 1, 2026 to extend the agreement's Outside Date from May 6, 2026 to August 6, 2026. The amendment is filed as Exhibit 2.1 to this Current Report on Form 8-K. The filing reiterates that a Registration Statement on Form S-4 (333-289994) including a preliminary proxy statement/prospectus has been filed and that shareholders will receive a definitive proxy statement/prospectus when available. The report also lists securities and tickers for the SPAC units, shares and warrants, and summarizes customary forward-looking risk factors tied to the proposed Business Combination.
SilverBox Corp IV entered into a First Amendment to its Business Combination Agreement with Parataxis entities on May 1, 2026. The amendment extends the agreement’s “Outside Date” for closing the proposed business combination from May 6, 2026 to August 6, 2026, giving the parties more time to satisfy closing conditions and complete the transaction. The company notes that a Registration Statement on Form S-4 containing a proxy statement/prospectus has been filed, and reiterates that shareholders should rely on those SEC materials when evaluating the deal.
SilverBox Corp IV (SBXD) is a Cayman Islands-based special purpose acquisition company formed in April 2024, with no operating revenues to date. It completed a 20,000,000-unit IPO at $10.00 per unit, placing $201,000,000 in a U.S. trust account to fund a future merger.
The sponsor holds 5,000,000 founder shares and 455,000 private placement units. As of March 19, 2026 there were 20,455,000 Class A and 5,000,000 Class B ordinary shares outstanding, and the non‑affiliate Class A float was valued at $216,413,900 as of December 31, 2025.
On August 6, 2025, SBXD entered into a Business Combination Agreement with Parataxis Holdings, using a two‑step merger into a new Delaware holding company, Pubco. Pubco also signed an optional equity facility with Yorkville Advisors for up to $400 million of Pubco Class A stock over 36 months after closing.
Silverbox Corp IV received an Amendment No. 2 to a Schedule 13G from a group of affiliated Sculptor Capital entities regarding its Class A ordinary shares. The filing is dated as of the event on 12/31/2025.
Sculptor Capital LP, Sculptor Capital II LP, Sculptor Capital Holding Corporation, Sculptor Capital Holding II LLC, Sculptor Capital Management, Inc., Sculptor Master Fund, Ltd., and Sculptor Special Funding, LP each report beneficial ownership of 0 Class A ordinary shares, representing 0% of the class. All report 0 shares with sole or shared voting and dispositive power.
The percentage calculations are based on 20,455,000 Class A ordinary shares, as set forth in Silverbox Corp IV’s 10-Q filed on November 12, 2025. The reporting group certifies the securities were not acquired or held to change or influence control of the issuer.
Mizuho Financial Group, Inc., a Japan-based parent holding company, reported beneficial ownership of 1,645,673 SilverBox Corp IV common shares, representing 8.0% of the class as of the event date 12/31/2025. Mizuho has sole power to vote and dispose of these shares, with no shared voting or dispositive power.
The filing notes that Mizuho Financial Group, Mizuho Bank, Ltd. and Mizuho Americas LLC may be deemed indirect beneficial owners of equity securities directly held by their wholly owned subsidiary, Mizuho Securities USA LLC. The securities are stated to be acquired and held in the ordinary course of business and not for changing or influencing control of SilverBox Corp IV.
W. R. Berkley Corporation and its subsidiary Berkley Insurance Company report beneficial ownership of 1,211,674 Class A ordinary shares of SilverBox Corp IV, representing 5.9% of the class.
The shares carry shared voting and dispositive power, with no sole power reported. The securities were acquired and are held in the ordinary course of business and are not intended to change or influence control of SilverBox Corp IV.
SilverBox Corp IV and Parataxis Holdings are pursuing a business combination to form PubCo, an institutional digital asset management and Bitcoin-focused treasury platform. The strategy combines fee-based asset management, principal capital deployment and BTC yield and accumulation, aiming to reinvest returns into a BTC-centric balance sheet.
Parataxis has built listed Bitcoin and Ethereum treasury vehicles in South Korea, raising about KRW 25 billion (~US$17 million) for Parataxis Korea since August 2025 and launching Parataxis Ethereum in January 2026. An illustrative framework shows fee-based EBITDA scaling with assets under management and highlights potential equity value both from recurring fees and balance sheet returns, alongside extensive risk disclosures tied to Bitcoin volatility, regulation, and SPAC-related dilution.
SilverBox Corp IV reports that Parataxis Holdings LLC has entered into a definitive agreement with Sinsiway Co. Ltd. in a transaction valued at up to KRW 35 billion. The deal is structured to give Parataxis Holdings a controlling interest in Sinsiway, subject to closing conditions. After closing, Sinsiway plans to change its name to Parataxis ETH, Inc. while remaining listed on the KOSDAQ. The parties describe the planned combination as creating South Korea’s first Ethereum-based treasury platform listed on the country’s public markets, anchored by U.S.-based institutional digital-asset investors. The 8-K also reminds SilverBox shareholders that a Registration Statement on Form S-4 for the broader business combination among SilverBox, Parataxis Holdings and a new holding company is on file with the SEC and will form the basis of the proxy and prospectus materials.
Highbridge Capital Management filed Amendment No. 1 to Schedule 13G reporting beneficial ownership of 280,000 Class A Ordinary Shares of SilverBox Corp IV (SBXD), representing 1.4% of the class.
The percentage is based on 20,455,000 Class A shares outstanding as of August 12, 2025 and assumes conversion of Class B shares held by Highbridge-advised funds. Highbridge reports sole voting power: 280,000 and sole dispositive power: 280,000. The filing certifies the securities were acquired and are held in the ordinary course and not for the purpose of changing or influencing control. Highbridge notes the funds have rights to dividends or sale proceeds on the reported shares.