[Form 4] Y-mAbs Therapeutics, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Y-mAbs Therapeutics insiders had outstanding stock options converted into cash as part of a completed merger. Under the merger agreement, each option outstanding immediately prior to the merger was canceled and converted into the right to receive cash equal to the number of shares subject to the option multiplied by the excess of the $8.60 per share merger consideration over the option exercise price. Options with an exercise price equal to or above the merger consideration were canceled without any payment. The reporting form shows an employee stock option with a $6.16 exercise price covering 142,600 shares that was converted into the right to receive cash for the difference between $8.60 and $6.16 per share.

Positive

• In-the-money options were converted to cash based on the spread to the $8.60 merger consideration, providing immediate realization for holders of such grants
• Uniform merger mechanics applied to vested and unvested options, creating consistent treatment across option holders

Negative

• Options with exercise prices equal to or above $8.60 were cancelled for no consideration, eliminating potential upside for those option holders
• Cancelling outstanding options removes future equity incentives tied to post-merger performance

Insights

Corporate Governance Expert

TL;DR: Merger triggered uniform treatment of options; in-the-money grants were cashed out, out-of-the-money grants were cancelled.

The Form 4 discloses a standard merger clause where all outstanding options were uniformly resolved at closing. This preserves equitable treatment across option holders by converting vested and unvested awards into cash based on the spread to the $8.60 per share merger consideration. The specific reported option had a $6.16 strike and 142,600 underlying shares, meaning it was in-the-money and therefore converted into a cash payment rather than being forfeited. The filing also notes that any options with strikes at or above the merger price were cancelled for no consideration, which is a material contractual outcome for affected holders.

Compensation Analyst

TL;DR: Management equity realized value through a cash-out formula; cancellation rule removes upside for higher-strike grants.

The disclosed mechanics convert option economics into immediate cash value equal to (merger consideration minus exercise price) times option shares, removing future equity upside but delivering certain monetary consideration to in-the-money option holders. The reported option (142,600 shares at a $6.16 exercise) was subject to this conversion. Simultaneously, holders of options with exercise prices at or above $8.60 received no consideration, which materially affects the compensation outcome for those participants and reduces potential dilution going forward for the surviving parent entity.

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^*

Gentilcore Douglas J

(Last) (First) (Middle)

C/O Y-MABS THERAPEUTICS, INC.

230 PARK AVENUE

(Street)

NEW YORK NY 10169

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP, Danyelza Bus. Unit Head

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

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)	$6.16	09/16/2025(1)		D			142,600	(2)	01/17/2035	Common Stock	142,600	(2)	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. 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"), 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 (the right to receive $8.60 per Share, in cash, without interest, subject to any applicable withholding of taxes (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
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What happened to Y-mAbs (YMAB) stock options in the merger?

All outstanding options were cancelled and converted into the right to receive cash equal to the number of shares subject to the option multiplied by the excess of the $8.60 merger consideration over the option exercise price.

Did the reporting person receive value for their options?

Yes. The filing reports an employee stock option with a $6.16 exercise price covering 142,600 shares that was converted into the right to receive cash for the difference between $8.60 and $6.16 per share.

Were any options cancelled with no payout?

Yes. The merger agreement states that any options with an exercise price equal to or greater than $8.60 were cancelled for no consideration.

Does the Form 4 show if options were vested or unvested?

The Form 4 indicates the merger converted both vested and unvested options into cash rights, but does not separately itemize vesting status for the reported option.

How is the cash amount for each option determined?

The cash per option equals the number of shares subject to the option multiplied by the excess of $8.60 (the merger consideration) over the option's exercise price.