---
schema_version: "secwatch.filing_event.v1"
accession: "0001213900-26-031849"
form_type: "8-K"
ticker: "CSTAF"
cik: "0001834032"
company_name: "Constellation Acquisition Corp I"
filed_at: "2026-03-19T23:59:59+00:00"
generated_at: "2026-05-15T09:41:10.905642+00:00"
event_type: "debt"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# Constellation Acquisition Corp I increases sponsor note by $3M to $5.25M

## Summary
- On March 18, 2026, Company and Sponsor amended promissory note: principal increased $3M to $5.25M.
- Note is unsecured, non-interest bearing, due upon consummation of initial business combination.
- Second amendment follows prior increase from $1.66M to $2.25M in June 2025.

## SEC filing metadata
- accession: 0001213900-26-031849
- form_type: 8-K
- ticker: CSTAF
- cik: 0001834032
- company_name: Constellation Acquisition Corp I
- filed_at: 2026-03-19T23:59:59+00:00
- event_type: debt
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 1.01, 2.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1834032/000121390026031849/0001213900-26-031849-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1834032/000121390026031849/ea0282507-8k_constellation1.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001213900-26-031849
- JSON: https://secwatch.observer/filing/0001213900-26-031849.json
- Plain text: https://secwatch.observer/filing/0001213900-26-031849.txt

## Source-grounded claims
- claim_id: 3e2378a3434bfdbc875f960023106927002a92f3
  claim: Constellation Acquisition Corp I amended loan of increase the principal amount by $3,000,000 from $2,250,000 to $5,250,000 with Constellation Sponsor LP.
  evidence_excerpt: On March 18, 2026, the Company further amended the Promissory Note (the “Second Amendment”), to increase the principal amount by $3,000,000 from $2,250,000 to $5,250,000.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1834032/000121390026031849/0001213900-26-031849-index.htm
- claim_id: 2fd03c1b38680a9a4c3b5127a595a3794d4b8238
  claim: Constellation Acquisition Corp I amended Second Amendment with Constellation Sponsor LP valued at $3,000,000 (effective 2026-03-18).
  evidence_excerpt: On March 18, 2026, the Company further amended the Promissory Note (the “Second Amendment”), to increase the principal amount by $3,000,000 from $2,250,000 to $5,250,000.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1834032/000121390026031849/0001213900-26-031849-index.htm

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