---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-25-090232"
form_type: "8-K"
ticker: null
cik: "0001722964"
company_name: "Y-mAbs Therapeutics, Inc."
filed_at: "2025-09-16T23:59:59+00:00"
generated_at: "2026-05-17T06:30:34.417522+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 1.0
calibrated_materiality_score: 1.0
confidence: "high"
source: SEC EDGAR
---

# Y-mAbs acquired by Perseus BidCo US; tender offer completed at $8.60/share, ~$413M total

## Summary
- Approximately 39.8M shares (~87.22%) tendered; Purchaser accepted all validly tendered shares.
- Merger closed Sep 16; each outstanding share (except excluded) converted to $8.60 cash.
- Aggregate consideration ~$413M funded via cash on hand and short-term financing.
- Shares to be delisted from Nasdaq; company will file Form 15 to suspend reporting obligations.
- All prior directors and officers resigned; new board and officers appointed (Vanessa Wolfeler, Robert Duffield, Daniel Dolan).

## SEC filing metadata
- accession: 0001104659-25-090232
- form_type: 8-K
- cik: 0001722964
- company_name: Y-mAbs Therapeutics, Inc.
- filed_at: 2025-09-16T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 1.0
- calibrated_materiality_score: 1.0
- confidence: high
- sec_items: 2.01, 3.01, 3.03, 5.01, 5.02, 5.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1722964/000110465925090232/0001104659-25-090232-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1722964/000110465925090232/tm2525998d2_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-25-090232
- JSON: https://secwatch.observer/filing/0001104659-25-090232.json
- Plain text: https://secwatch.observer/filing/0001104659-25-090232.txt

## Key facts
- Governance Changes
  Y-mAbs Therapeutics, Inc.: By-laws amended and restated in their entirety.
  - Change: bylaw amendment
  source text: at the Effective Time, the Company’s by-laws (the “ By-Laws ”) were amended and restated in their entirety.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1722964/000110465925090232/0001104659-25-090232-index.htm
- Governance Changes
  Y-mAbs Therapeutics, Inc.: Certificate of incorporation amended and restated in its entirety.
  - Change: charter amendment
  source text: at the Effective Time, the certificate of incorporation of the Company (the “ Certificate of Incorporation ”) was amended and restated in its entirety.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1722964/000110465925090232/0001104659-25-090232-index.htm

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