Merus N.V. — Director's Dealing 2021

Apr 1, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Merus N.V. (MRUS)
CIK: 0001651311
Period of Report: 2021-03-30

Reporting Person: BVF PARTNERS L P/IL (10% Owner)
Reporting Person: BIOTECHNOLOGY VALUE FUND L P (See Explanation of Responses)
Reporting Person: BVF I GP LLC (See Explanation of Responses)
Reporting Person: BIOTECHNOLOGY VALUE FUND II LP (See Explanation of Responses)
Reporting Person: BVF II GP LLC (See Explanation of Responses)
Reporting Person: Biotechnology Value Trading Fund OS LP (See Explanation of Responses)
Reporting Person: BVF Partners OS Ltd. (See Explanation of Responses)
Reporting Person: BVF GP HOLDINGS LLC (10% Owner)
Reporting Person: BVF INC/IL (10% Owner)
Reporting Person: LAMPERT MARK N (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-03-30	Common Shares, (euro)0.09 nominal value per share	P	165000	$19.75	Acquired	3803152	Direct
2021-03-30	Common Shares, (euro)0.09 nominal value per share	P	108106	$19.75	Acquired	2892385	Direct
2021-03-30	Common Shares, (euro)0.09 nominal value per share	P	26894	$19.75	Acquired	462015	Direct

Footnotes

F1: This Form 4 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF I GP LLC ("BVF GP"), BVF II GP LLC ("BVF2 GP"), BVF GP Holdings LLC ("BVF GPH"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Each of the Reporting Persons is a member of a Section 13(d) group that collectively owns more than 10% of the Issuer's outstanding Common Shares, (euro)0.09 nominal value per share. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein.

F2: Securities owned directly by BVF. As the general partner of BVF, BVF GP may be deemed to beneficially own the securities owned directly by BVF. As the sole member of BVF GP, BVF GPH may be deemed to beneficially own securities owned directly by BVF. As the investment manager of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF.

F3: Securities owned directly by BVF2. As the general partner of BVF2, BVF2 GP may be deemed to beneficially own the securities owned directly by BVF2. As the sole member of BVF2 GP, BVF GPH may be deemed to beneficially own securities owned directly by BVF2. As the investment manager of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2.

F4: Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS.