[Form 4] Merus N.V. Insider Trading Activity

Rhea-AI Filing Summary

Merus N.V. discloses that a director participated in the cash tender offer launched by Genmab’s subsidiary for all issued and outstanding Merus common shares. On December 12, 2025, the director tendered 73,576 common shares, which were accepted at a cash price of $97.00 per share, leaving the director with no remaining common shares after the transaction.

The report also explains that several Merus stock options held by the director, covering blocks of shares such as 13,193, 8,844 and 14,414, with exercise prices including $41.60, $48.73 and $23.29 per share, were cancelled under the transaction agreement. In each case, the option was exchanged for cash equal to the amount by which the $97.00 offer price exceeded the option’s exercise price, multiplied by the number of underlying shares, so the director now reports holding no derivative securities.

Insights

Equity governance analyst

Director tenders all Merus equity into Genmab’s $97 cash offer.

This report shows how a Merus N.V. director’s equity was treated in the change-of-control transaction with Genmab A/S. The director tendered 73,576 common shares into a tender offer for all issued and outstanding shares at $97.00 per share, accepted on December 12, 2025. After this tender, the director no longer owns Merus common shares.

The filing further details the treatment of stock options. Multiple options with exercise prices such as $41.60, $48.73 and $13.35 per share, and expirations extending to 2035, were cancelled under the transaction agreement. For each option, the holder receives cash equal to the in-the-money value: the difference between the $97.00 offer consideration and the exercise price, multiplied by the number of underlying shares. Following these adjustments, the director reports zero derivative securities, illustrating the standard cash-out mechanics applied to equity awards in this acquisition.

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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Iwicki Mark T

(Last) (First) (Middle)

C/O MERUS N.V.

UPPSALALAAN 17

(Street)

UTRECHT P7 3584 CT

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Merus N.V. [ MRUS ]

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)
12/12/2025

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 Shares	12/12/2025		U		73,576	D	$97(1)	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
Share Option (right to buy)	$41.6	12/12/2025		D			13,193	(2)	05/22/2035	Common Shares	13,193	$0	0	D
Share Option (right to buy)	$48.73	12/12/2025		D			8,844	(2)	05/07/2034	Common Shares	8,844	$0	0	D
Share Option (right to buy)	$23.29	12/12/2025		D			14,414	(2)	06/08/2033	Common Shares	14,414	$0	0	D
Share Option (right to buy)	$18.56	12/12/2025		D			16,604	(2)	05/31/2032	Common Shares	16,604	$0	0	D
Share Option (right to buy)	$21.15	12/12/2025		D			6,120	(2)	05/28/2031	Common Shares	6,120	$0	0	D
Share Option (right to buy)	$16.09	12/12/2025		D			8,631	(2)	06/30/2030	Common Shares	8,631	$0	0	D
Share Option (right to buy)	$19.12	12/12/2025		D			5,650	(2)	05/24/2027	Common Shares	5,650	$0	0	D
Share Option (right to buy)	$23.3	12/12/2025		D			4,983	(2)	07/20/2028	Common Shares	4,983	$0	0	D
Share Option (right to buy)	$13.35	12/12/2025		D			8,500	(2)	06/12/2029	Common Shares	8,500	$0	0	D

Explanation of Responses:

1. On September 29, 2025, Merus N.V. (the "Issuer") entered into a transaction agreement (as it may be amended, supplemented or otherwise modified from time to time, the "Transaction Agreement") with Genmab A/S ("Genmab") and its wholly owned subsidiary, Genmab Holding II B.V. (the "Purchaser"). Pursuant to the terms of the Transaction Agreement, the Purchaser commenced a tender offer for all the issued and outstanding common shares, par value EUR 0.09 per share (the "Shares"), of the Issuer (the "Offer"), and, on December 12, 2025 (the "Acceptance Time"), the Purchaser accepted all of the Shares that were validly tendered and not properly withdrawn pursuant to the Offer as of the Acceptance Time, including the Shares tendered by the reporting person, in exchange for a cash payment equal to $97.00 per Share, without interest and less applicable withholding taxes (the "Offer Consideration"), which Offer Consideration will be paid as soon as practicable following the Acceptance Time.

2. This option was cancelled pursuant to the Transaction Agreement in exchange for cash (without interest and net of applicable withholding tax and other applicable deductions) in an amount equal to the product of (i) the amount by which the Offer Consideration exceeds the applicable exercise price per Share of such option and (ii) the aggregate number of Shares underlying such option.

	/s/ Peter Silverman as attorney-in-fact	12/12/2025
	** Signature of Reporting Person	Date
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