Y-mAbs Therapeutics files 14D-9 on $8.60 per share buyout proposal

Rhea-AI Filing Summary

Y-mAbs Therapeutics (YMAB) has filed a Schedule 14D-9 in response to a proposed acquisition. Perseus BidCo US, Inc. will launch a cash tender offer at $8.60 per share for all outstanding YMAB common stock, to be followed by a Section 251(h) short-form merger that will leave the company as the surviving entity. The buyer’s wholly owned subsidiary, Yosemite Merger Sub, will be merged into YMAB immediately after successful completion of the tender, eliminating any need for a separate stockholder vote.

• Deal structure: all-cash offer; merger effected under Delaware law for speed and certainty.
• Key date: Merger Agreement signed 4 Aug 2025; internal communications to employees dated 6 Aug 2025.
• Next step: Purchaser will formally commence the tender offer; YMAB’s Board will issue its recommendation in subsequent filings.

This filing only includes two exhibits—an employee message and FAQ—indicating the transaction is at the communications stage; no financial results or closing conditions are detailed.

Positive

• All-cash $8.60 per share offer provides immediate liquidity and price certainty for YMAB shareholders.

Negative

• None.

Insights

M&A Specialist

TL;DR: Cash tender at $8.60 offers liquidity; closing still subject to tender conditions.

The all-cash consideration delivers immediate, certain value and simplifies closing via Section 251(h), which bypasses a shareholder vote once a majority of shares are tendered. Lack of disclosed termination conditions or financing contingencies in this excerpt limits visibility into deal risk. Investors should watch future 14D-9 amendments for the Board’s formal fairness opinion and any competing bids.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14D-9

Solicitation/Recommendation Statement

Under Section 14(d)(4) of the Securities Exchange Act of 1934

Y-MABS THERAPEUTICS, INC.

(Name of Subject Company)

Y-MABS THERAPEUTICS, INC.

(Name of Persons Filing Statement)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

984241109

(CUSIP Number of Class of Securities)

Michael Rossi

President and Chief Executive Officer

Y-mAbs Therapeutics, Inc.

202 Carnegie Center Drive

Suite 301

Princeton, New Jersey 08540

(646) 885-8505

(Name, address, and telephone number of person authorized to receive notices and communications

on behalf of the persons filing statement)

With a copy to:

Divakar Gupta

Sarah K. Sellers

Bill Sorabella

Bill Roegge

Cooley LLP

55 Hudson Yards

New York, New York 10001

(212) 479-6000

x Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

This Schedule 14D-9 filing consists of certain communications relating to the proposed acquisition of Y-mAbs Therapeutics, Inc., a Delaware corporation (the “Company” or “Y-mAbs”), by Perseus BidCo US, Inc., a Delaware corporation (“Parent”), and Yosemite Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Purchaser”), pursuant to the terms and subject to the conditions of an Agreement and Plan of Merger, dated as of August 4, 2025 (the “Merger Agreement”), by and among the Company, Parent, Purchaser, and Stark International Lux, a Luxembourg private limited liability company (société à responsabilité limitée). Pursuant to the Merger Agreement, upon the terms and subject to the conditions thereof, Purchaser will commence a tender offer (the “Tender Offer”) to acquire all of the outstanding shares of common stock of the Company, $0.0001 par value per share (the “Shares”), at an offer price of $8.60 per Share in cash, without interest, and subject to any applicable withholding taxes. If successful, the Tender Offer will be followed by a merger of Purchaser with and into the Company (the “Merger”) pursuant to Section 251(h) of the Delaware General Corporation Law, with the Company continuing as the surviving corporation in the Merger.

This Schedule 14D-9 filing consists of the following communications relating to the proposed Tender Offer and the Merger:

	·	Exhibit 99.1: A message to Company employees from Parent, dated August 6, 2025.
	·	Exhibit 99.2: Employee FAQ, dated August 6, 2025.

FAQ

What is Perseus BidCo US, Inc. offering for YMAB shares?

The purchaser intends to pay $8.60 in cash per share for all outstanding YMAB common stock.

Will Y-mAbs shareholders need to vote on the merger?

No. The merger will occur under Section 251(h), requiring only successful completion of the tender offer.

When was the merger agreement signed?

The Agreement and Plan of Merger was executed on August 4, 2025.

What happens after the tender offer is completed?

Yosemite Merger Sub will merge into Y-mAbs, with the company surviving as a wholly owned subsidiary of Parent.

Where can employees find more information?

Exhibit 99.1 (employee message) and Exhibit 99.2 (employee FAQ) accompany this filing.