---
schema_version: "secwatch.filing_event.v1"
accession: "0001929980-25-000400"
form_type: "8-K"
ticker: "HSPT"
cik: "0002032950"
company_name: "Horizon Space Acquisition II Corp."
filed_at: "2025-05-12T23:59:59+00:00"
generated_at: "2026-05-22T00:45:56.416661+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Horizon Space Acquisition II SPAC to merge with SL Bio at $5.568B enterprise value

## Summary
- SL Bio develops cellular and gene therapies; will become wholly owned sub of PubCo via two-step merger.
- SPAC shareholders to receive one PubCo ordinary share per share; SL Bio holders get shares based on $5.568B / $10.00 ratio.
- Transactions require approvals from both companies' shareholders, Nasdaq listing, and regulatory clearances.
- Sponsor and certain SL Bio shareholders enter lock-up; shares restricted until 150 days post-close or $12.00 trigger.
- Sponsor support agreement ensures voting in favor; shareholder support agreement covers key SL Bio holders.

## SEC filing metadata
- accession: 0001929980-25-000400
- form_type: 8-K
- ticker: HSPT
- cik: 0002032950
- company_name: Horizon Space Acquisition II Corp.
- filed_at: 2025-05-12T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 1.01, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2032950/000192998025000400/0001929980-25-000400-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2032950/000192998025000400/hspt_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001929980-25-000400
- JSON: https://secwatch.observer/filing/0001929980-25-000400.json
- Plain text: https://secwatch.observer/filing/0001929980-25-000400.txt

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