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

Rhea-AI Filing Summary

Peter P. Freundschuh, EVP, CFO and Treasurer of Y-mAbs Therapeutics, Inc. (YMAB), reported that on 09/16/2025 a merger transaction closed under which his equity awards were cancelled and converted to cash. Pursuant to the Merger Agreement, outstanding restricted stock units (RSUs) and performance RSUs (PRSU) were converted into a cash payout equal to $8.60 per share. Outstanding stock options were cancelled and converted into cash equal to the excess of the $8.60 merger consideration over each option's exercise price; options with exercise prices at or above $8.60 were cancelled without consideration. The Form 4 shows disposition entries on 09/16/2025: 77,800 shares of Common Stock disposed, cancellation/conversion of 170,000 options at $12.47, 63,500 options at $6.16, and two RSU/PRSU line items of 15,900 each. Following the reported transactions the filing reports 0 shares or derivative securities beneficially owned.

Positive

• Clear contractual treatment of awards: RSUs, PRSUs and options were converted to cash per the Merger Agreement at a disclosed per-share consideration of $8.60.
• Complete disposition reporting: The Form 4 lists specific counts for cancelled awards and resulting beneficial ownership of 0, providing transparency for investors and regulators.

Negative

• Loss of insider equity upside: The reporting person’s equity and option exposure was eliminated, removing potential future alignment via company stock ownership.
• Some options out-of-the-money: Options with exercise prices equal to or above the $8.60 Merger Consideration were cancelled for no consideration per the filing.

Insights

Corporate Governance Expert

TL;DR: Insider's equity awards were cashed out in a controlled merger, removing outstanding insider-held equity.

The Form 4 documents a change in beneficial ownership driven by a corporate acquisition where the reporting person’s RSUs, PRSUs and stock options were cancelled and converted to cash per the Merger Agreement. This is a routine outcome of a stock-for-cash acquisition clause: equity awards become contractual cash consideration rather than ongoing equity. For governance, the transaction centralizes ownership under the acquiror and eliminates potential insider-aligned equity incentives at the target going forward. The filing correctly itemizes cancelled awards and the per-share cash consideration of $8.60, and it shows the reporting person holds no remaining direct or derivative common stock following the effective time.

Compensation / M&A Specialist

TL;DR: Compensation awards converted to cash on merger close; option payoff depends on strike relative to $8.60 consideration.

The disclosure clarifies treatment of different award types: RSUs and PRSUs were converted to cash equal to the maximum shares multiplied by $8.60; options were cashed out for the intrinsic value (Merger Consideration minus exercise price) and those with exercise prices >= $8.60 were voided for no consideration. The Form 4 quantifies the cancelled instruments (170,000 options at $12.47; 63,500 options at $6.16; two RSU/PRSU tranches of 15,900 each; 77,800 common shares disposed), enabling calculation of the gross cash payouts under the agreement without additional assumptions. This is standard M&A compensation treatment and materially affects the reporting person’s equity exposure.

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^*

PFREUNDSCHUH PETER P.

(Last) (First) (Middle)

C/O Y-MABS THERAPEUTICS, INC.

230 PARK AVENUE, SUITE 3350

(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)
	EVP, CFO and Treasurer

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)		D		77,800(2)	D	(3)	0	D

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)	$12.47	09/16/2025(1)		D			170,000	(4)	07/12/2034	Common Stock	170,000	(4)	0	D
Employee Stock Option (right to buy)	$6.16	09/16/2025(1)		D			63,500	(4)	01/17/2035	Common Stock	63,500	(4)	0	D
Restricted Stock Units(5)	(6)	09/16/2025(1)		D			15,900	(6)	(6)	Common Stock	15,900	(6)	0	D
Restricted Stock Units(5)	(6)	09/16/2025(1)		D			15,900	(6)	(6)	Common Stock	15,900	(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. 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.

3. 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 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 right to receive $8.60 per Share, in cash, without interest, subject to any applicable withholding of taxes (the "Merger Consideration").

4. 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.

5. Performance-Based RSUs ("PRSUs") granted to the Reporting Person pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc. Each PRSU represents a contingent right to receive one share of Common Stock on the vesting dates of the PRSU.

6. At the Effective Time, pursuant to the Merger Agreement, each PRSU 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 maximum number of Shares issuable in settlement of such PRSU award immediately prior to the Effective Time, multiplied by (b) the Merger 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 Peter P. Freundschuh's YMAB equity on 09/16/2025?

All listed RSUs, PRSUs and stock options were cancelled and converted to cash in connection with the Merger, and reported beneficial ownership is 0.

What cash consideration per share was used to convert YMAB awards in the Merger?

$8.60 per share was the Merger Consideration applied to outstanding RSUs and PRSUs as stated in the Form 4.

How were stock options treated in the YMAB merger according to the Form 4?

Options were cancelled and converted into cash equal to the excess of the Merger Consideration over each option’s exercise price; options with exercise prices >= $8.60 were cancelled for no consideration.

What specific awards and quantities did the Form 4 report for the reporting person?

The Form 4 reports disposition/cancellation of 77,800 common shares, 170,000 options at $12.47, 63,500 options at $6.16, and two RSU/PRSU tranches of 15,900 each.

Does the Form 4 show any remaining beneficial ownership after the Merger?

No. The filing reports 0 shares or derivative securities beneficially owned following the reported transactions.