Y-mAbs (YMAB) completes $8.60 cash merger; RSUs and options cashed out

Rhea-AI Filing Summary

Healy James, a Sofinnova-affiliated director of Y-mAbs Therapeutics (YMAB), reported transactions tied to the company's merger. On 09/16/2025 Purchaser completed a tender offer and merged with the issuer, and each outstanding common share was cancelled for $8.60 cash per share. The reporting person disposed of 31,603 shares and 25,080 restricted stock units were converted into cash in connection with the merger. Outstanding stock options were cancelled and converted into cash equal to the excess of $8.60 over each option's exercise price; options with exercise prices at or above $8.60 were cancelled for no consideration.

Positive

• Merger completed with definitive cash consideration of $8.60 per share, providing a known liquidity outcome for shareholders
• RSUs and in-the-money options were converted into cash pursuant to the Merger Agreement, monetizing equity awards for holders

Negative

• Options with exercise prices equal to or exceeding $8.60 were cancelled for no consideration, eliminating potential upside for those awards
• Reporting person disclaims beneficial ownership except for pecuniary interest, which may limit clarity on voting influence

Insights

Financial Analyst

TL;DR: The merger produced a fixed cash exit of $8.60 per share, monetizing equity and cancelling options and RSUs.

The Form 4 documents that on 09/16/2025 Y-mAbs completed a merger and paid $8.60 per share in cash. For an investor-focused view, the key takeaway is liquidity at a known price for all outstanding common shares, with RSUs and in-the-money options converted to cash based on the $8.60 consideration and out-of-the-money options cancelled. The filing quantifies share and derivative counts exchanged or cancelled, enabling straightforward estimation of cash proceeds to insiders from the transaction.

Corporate Governance Expert

TL;DR: Insider reporting aligns with Merger Agreement mechanics: share cancellations and cash-outs are disclosed clearly.

The report shows compliance with Section 16 reporting for a controlling transaction: the reporting person lists direct and indirect holdings, notes conversion mechanics for RSUs and options, and disclaims beneficial ownership except for pecuniary interest via Sofinnova entities. The disclosure that certain options were cancelled without consideration where exercise price met or exceeded $8.60 is material to governance and executive compensation outcomes.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

HEALY JAMES

(Last) (First) (Middle)

C/O SOFINNOVA INVESTMENTS INC.

3000 SAND HILL ROAD, BLDG. 4, SUITE 250

(Street)

MENLO PARK CA 94025

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Y-mAbs Therapeutics, Inc. [ YMAB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/16/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/16/2025(1)		U		31,603	D	$8.6(2)	0	D
Common Stock	09/16/2025(1)		D		25,080(3)	D	(4)	0	D
Common Stock	09/16/2025(1)		U		2,194,278	D	$8.6(2)	0	I	See footnote(5)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$11.16	09/16/2025(1)		D			14,222	(6)	04/24/2028	Common Stock	14,222	(6)	0	D
Employee Stock Option (right to buy)	$21.45	09/16/2025(1)		D			8,000	(6)	06/12/2029	Common Stock	8,000	(6)	0	D
Employee Stock Option (right to buy)	$48.67	09/16/2025(1)		D			11,000	(6)	06/23/2030	Common Stock	11,000	(6)	0	D
Employee Stock Option (right to buy)	$37.53	09/16/2025(1)		D			11,000	(6)	06/10/2031	Common Stock	11,000	(6)	0	D
Employee Stock Option (right to buy)	$16.64	09/16/2025(1)		D			16,000	(6)	07/15/2032	Common Stock	16,000	(6)	0	D
Employee Stock Option (right to buy)	$8.13	09/16/2025(1)		D			13,950	(6)	06/08/2033	Common Stock	13,950	(6)	0	D
Employee Stock Option (right to buy)	$12.01	09/16/2025(1)		D			14,545	(6)	06/11/2034	Common Stock	14,545	(6)	0	D
Employee Stock Option (right to buy)	$4.51	09/16/2025(1)		D			33,450	(6)	06/30/2035	Common Stock	33,450	(6)	0	D

Explanation of Responses:

1. Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

2. Pursuant to the terms of the Merger Agreement, the Shares were tendered at the Offer Acceptance Time (as defined in the Merger Agreement) in exchange for the right to receive $8.60 per Share, in cash, without interest, subject to any applicable withholding of taxes (the "Merger Consideration"). At the effective time of the Merger (being such date and at such time as the certificate of merger in respect of the Merger was duly filed with the Secretary of State of the State of Delaware in accordance with the DGCL) (the "Effective Time"), each issued and outstanding Share was cancelled in exchange for the Merger Consideration.

3. Represents restricted stock units ("RSUs") granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan. Each RSU represents a contingent right to receive one share of Common Stock on the vesting dates of the RSU.

4. At the Effective Time, pursuant to the Merger Agreement, each RSU award outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive an amount in cash, without interest, equal to the product of (a) the total number of Shares issuable in settlement of such RSU award immediately prior to the Effective Time, multiplied by (b) the Merger Consideration.

5. The Reporting Person is one of the managing members of the general partner of Sofinnova Management X-A, L.L.C., the general partner of Sofinnova Management X, L.P., the general partner of Sofinnova Venture Partners X, L.P., which directly holds the reported securities, and, as such, may be deemed to share voting and investment power over such shares. The Reporting Person disclaims beneficial ownership of the reported securities, except to the extent of his proportionate pecuniary interest in Sofinnova Ventures Partners X, L.P.

6. At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

Remarks:

The foregoing descriptions in the footnotes to this Form 4 are qualified in their entirety by reference to the terms of the Merger Agreement. In the event of any conflict between the descriptions above and the terms set forth in the Merger Agreement, the terms set forth in the Merger Agreement shall control.

	/s/ John LaRocca, Attorney-in-Fact	09/18/2025
	** Signature of Reporting Person	Date
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FAQ

What was the merger consideration paid to Y-mAbs (YMAB) shareholders?

$8.60 per share in cash, without interest, subject to applicable tax withholding.

When was the Merger and related insider transactions completed?

09/16/2025 is the transaction and effective date referenced in the Form 4.

How were RSUs and stock options treated in the merger?

All RSUs and Options outstanding were cancelled and converted into the right to receive cash equal to the number of shares times the merger consideration or, for options, the excess of $8.60 over the exercise price; options with exercise prices ≥ $8.60 were cancelled for no consideration.

How many common shares did the reporting person dispose of?

31,603 shares were reported disposed of on 09/16/2025.

Does the reporting person claim direct beneficial ownership of the reported shares?

No. The reporting person states they may be deemed to share voting and investment power via Sofinnova entities and disclaim beneficial ownership except for proportionate pecuniary interest.