---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-26-054874"
form_type: "8-K"
ticker: "SBXD"
cik: "0002015947"
company_name: "SilverBox Corp IV"
filed_at: "2026-05-04T23:59:59+00:00"
generated_at: "2026-05-15T00:04:42.219647+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# SilverBox Corp IV extends business combination deadline with Parataxis to August 6, 2026

## Summary
- First Amendment to Business Combination Agreement extends Outside Date from May 6, 2026 to August 6, 2026.
- Original agreement was dated August 6, 2025; amendment signed on May 1, 2026.
- Extension provides additional time to satisfy closing conditions for the SPAC merger.
- No other terms of the Business Combination Agreement were modified.

## SEC filing metadata
- accession: 0001104659-26-054874
- form_type: 8-K
- ticker: SBXD
- cik: 0002015947
- company_name: SilverBox Corp IV
- filed_at: 2026-05-04T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2015947/000110465926054874/0001104659-26-054874-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2015947/000110465926054874/tm2613455d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-26-054874
- JSON: https://secwatch.observer/filing/0001104659-26-054874.json
- Plain text: https://secwatch.observer/filing/0001104659-26-054874.txt

## Source-grounded claims
- claim_id: 9fc2bfe71d534a8e5d02480dd6f83bcf8a18aff0
  claim: SilverBox Corp IV amended First Amendment (effective 2026-05-01).
  evidence_excerpt: On May 1, 2026, the parties to the Business Combination Agreement entered into the First Amendment to the Business Combination Agreement (the “First Amendment”), which amends the Business Combination Agreement to extend the Outside Date from May 6, 2026 to August 6, 2026.
  evidence_url: https://www.sec.gov/Archives/edgar/data/2015947/000110465926054874/0001104659-26-054874-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.