Mizuho Financial Group, Inc. filed Amendment No. 1 to Schedule 13G with the SEC on November 12, 2026, disclosing zero beneficial ownership of Common Shares of SilverBox Corp IV as of September 30, 2026.

Key Highlights

  • Reporting person: Mizuho Financial Group, Inc., organized in Japan and classified as a Parent Holding Company (FI) in the filing.
  • Aggregate beneficial ownership: 0 shares, representing 0.0% of the class of Common Shares, as of the September 30, 2026 event date.
  • All voting and dispositive powers: Sole voting, shared voting, sole dispositive, and shared dispositive powers are each reported as 0.
  • Subsidiary relationship: The filing states that Mizuho Financial Group, Inc., Mizuho Bank, Ltd., and Mizuho Americas LLC "may be deemed to be indirect beneficial owners of said equity securities directly held by Mizuho Securities USA LLC," which the filing describes as their wholly-owned subsidiary.
  • Issuer address: SilverBox Corp IV is located at 8701 Bee Cave Road, East Building Suite 310, Austin, TX 78746, according to the filing.
  • Signed by: Takahiro Katsura, Managing Director, Global Corporate Function Coordination Department, on November 12, 2026.

Mizuho Financial Group Amends SilverBox Corp IV Holdings Report to Zero

Mizuho Financial Group, Inc. submitted Amendment No. 1 to its Schedule 13G regarding Common Shares of SilverBox Corp IV (CUSIP G81354105), with a triggering event date of September 30, 2026. The filing identifies Mizuho Financial Group as a Parent Holding Company based in Tokyo, Japan, filing under Item 3 as a parent holding company or control person in accordance with Rule 240.13d-1(b)(1)(ii)(G).

According to the filing, the aggregate amount of Common Shares beneficially owned by Mizuho Financial Group, Inc. is 0, representing 0.0% of the class. All four categories of ownership power, sole voting, shared voting, sole dispositive, and shared dispositive, are each reported as 0. The filing notes that Mizuho Securities USA LLC, described as a wholly-owned subsidiary of Mizuho Financial Group, Inc., Mizuho Bank, Ltd., and Mizuho Americas LLC, directly holds the equity securities at issue, though the aggregate beneficial ownership reported for the parent is zero.

The filing includes a certification stating that the securities "were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer." Item 5 of the filing designates the ownership position as 5 percent or less of the class. The filing references Exhibit A for identification and classification of the relevant subsidiary, consistent with the parent holding company filing requirement. No ticker symbol for SilverBox Corp IV appears in the filing text itself.

What Was Disclosed

Mizuho Financial Group, Inc. filed Amendment No. 1 to Schedule 13G disclosing zero beneficial ownership of SilverBox Corp IV Common Shares as of September 30, 2026, with all voting and dispositive powers also reported as zero.