Document:

EX-4.2

 Exhibit 4.2 

MERUS N.V. 

2016 INCENTIVE AWARD PLAN 

ARTICLE I. 
 PURPOSE

 The Plan’s purpose is to enhance the Company’s ability to attract, retain and motivate persons who make (or are expected to
make) important contributions to the Company by providing these individuals with equity ownership opportunities. Capitalized terms used in the Plan are defined in Article XI. 

ARTICLE II. 
 ELIGIBILITY

 Service Providers are eligible to be granted Awards under the Plan, subject to the limitations described herein. 

ARTICLE III. 

ADMINISTRATION AND DELEGATION 

3.1 Administration. The Plan is administered by the Administrator. 

3.2 Grant Authority. Subject to the conditions and limitations in the Plan and Applicable Laws, (a) the Supervisory Board has
authority to grant Awards and set Award terms and conditions for Service Providers that are members of the Management Board, and (b) the Management Board has authority to grant Awards and set Award terms and conditions for any other Service
Providers who are not members of the Supervisory Board. The members of the Supervisory Board will be granted Awards in accordance with the Merus N.V. Supervisory Board Member Compensation Program as determined by the general meeting of shareholders
of the Company. 
 3.3 With due observance of the division of authority described in Section 3.2 hereof, the Administrator has the
authority to take all actions and make all determinations under the Plan, to interpret the Plan and Award Agreements on behalf of the Company and to adopt, amend and repeal Plan administrative rules, guidelines and practices as it deems advisable.
The Administrator may correct defects and ambiguities, supply omissions and reconcile inconsistencies in the Plan or any Award as it deems necessary or appropriate to administer the Plan and any Awards. The Administrator’s determinations under
the Plan are in its sole discretion. Notwithstanding anything in the Plan to the contrary, all actions taken by the Management Board under the Plan shall be subject to the conditions and limitations set forth in the Management Board Rules of
Procedure. 
 3.4 Appointment of Committees. To the extent the Articles and Applicable Laws permit, the Management Board and/or the
Supervisory Board may delegate any or all of its powers under the Plan to one or more Committees or officers of the Company or any of its Subsidiaries. The Management Board or the Supervisory Board, respectively, may abolish any Committee it
established or re-vest in itself any previously delegated authority at any time. 

 ARTICLE IV. 

SHARES AVAILABLE FOR AWARDS 
 4.1
Number of Shares. Subject to adjustment under Article VIII and the terms of this Article IV, Awards may be made under the Plan covering up to the Overall Share Limit. As of the Plan’s effective date under Section 10.3, the Company
will cease granting awards under the Prior Plans; however, Prior Plan Awards will remain subject to the terms of the applicable Prior Plan. Shares issued under the Plan may consist of authorized but unissued Shares, Shares purchased on the open
market or treasury Shares. 
 4.2 Share Recycling. If all or any part of an Award expires, lapses or is terminated, exchanged for
cash, surrendered, repurchased, canceled without having been fully exercised or forfeited, in any case, in a manner that results in the Company acquiring Shares covered by the Award at a price not greater than the price (as adjusted to reflect any
Equity Restructuring) paid by the Participant for such Shares or not issuing any Shares covered by the Award, the unused Shares covered by the Award will again be available for Award grants under the Plan. Further, Shares delivered (either by actual
delivery or attestation) to the Company by a Participant to satisfy the applicable exercise or purchase price of an Award and/or to satisfy any applicable tax withholding obligation (including Shares retained by the Company from the Award being
exercised or purchased and/or creating the tax obligation) will again be available for Award grants under the Plan. The payment of Dividend Equivalents in cash in conjunction with any outstanding Awards shall not count against the Overall Share
Limit. 
 4.3 Substitute Awards. With due observance of the division of authority described in Section 3.2 hereof, in connection
with an entity’s merger or consolidation with the Company or the Company’s acquisition of an entity’s property or stock, the Administrator may grant Awards in substitution for any options or other stock or stock-based awards granted
before such merger or consolidation by such entity or its affiliate. Substitute Awards may be granted on such terms as the Administrator deems appropriate, notwithstanding limitations on Awards in the Plan. Substitute Awards will not count against
the Overall Share Limit (nor shall Shares subject to a Substitute Award be added to the Shares available for Awards under the Plan as provided above), except that Shares acquired by exercise of substitute Incentive Stock Options will count against
the maximum number of Shares that may be issued pursuant to the exercise of Incentive Stock Options under the Plan. Additionally, in the event that a company acquired by the Company or any Subsidiary or with which the Company or any Subsidiary
combines has shares available under a pre-existing plan approved by stockholders and not adopted in contemplation of such acquisition or combination, the shares available for grant pursuant to the terms of
such pre-existing plan (as adjusted, to the extent appropriate, using the exchange ratio or other adjustment or valuation ratio or formula used in such acquisition or combination to determine the consideration
payable to the holders of common stock of the entities party to such acquisition or combination) may be used for Awards under the Plan and shall not reduce the Shares authorized for grant under the Plan (and Shares subject to such Awards shall not
be added to the Shares available for Awards under the Plan as provided above); provided that Awards using such available shares shall not be made after the date awards or grants could have been made under the terms of the pre-existing plan, absent the acquisition or combination, and shall only be made to individuals who were not Employees or members of the Management Board or Supervisory Board prior to such acquisition or
combination. 
 ARTICLE V. 

STOCK OPTIONS AND STOCK APPRECIATION RIGHTS 

5.1 General. With due observance of the division of authority described in Section 3.2 hereof, the Administrator (i) may
grant Options or Stock Appreciation Rights to Service Providers subject to the limitations in the Plan, including any limitations in the Plan that apply to Incentive Stock Options, and (ii) will determine the number of Shares covered by each
Option and Stock Appreciation Right, the exercise price of each Option and Stock Appreciation Right and the conditions and limitations applicable to the exercise of each Option and Stock Appreciation Right. A Stock Appreciation Right will entitle
the 

 
Participant (or other person entitled to exercise the Stock Appreciation Right) to receive from the Company upon exercise of the exercisable portion of the Stock Appreciation Right an amount
determined by multiplying the excess, if any, of the Fair Market Value of one Share on the date of exercise over the exercise price per Share of the Stock Appreciation Right by the number of Shares with respect to which the Stock Appreciation Right
is exercised, subject to any limitations of the Plan or that the Administrator may impose and payable in cash, Shares valued at Fair Market Value or a combination of the two as the Administrator may determine or provide in the Award Agreement. 

5.2 Exercise Price. The Administrator will establish each Option’s and Stock Appreciation Right’s exercise price and specify
the exercise price in the Award Agreement. Unless otherwise determined by the Administrator, the exercise price will not be less than 100% of the Fair Market Value on the grant date of the Option or Stock Appreciation Right. Notwithstanding the
foregoing, if on the last day of the term of an Option or Stock Appreciation Right the Fair Market Value of one Share exceeds the applicable exercise or base price per Share, the Participant has not exercised the Option or Stock Appreciation Right
and remains employed by the Company or one of its Subsidiaries and the Option or Stock Appreciation Right has not expired, the Option or Stock Appreciation Right shall be deemed to have been exercised by the Participant on such day with payment made
by withholding Shares otherwise issuable in connection with its exercise. In such event, the Company shall deliver to the Participant the number of Shares for which the Option or Stock Appreciation Right was deemed exercised, less the number of
Shares required to be withheld for the payment of the total purchase price and required withholding taxes; provided, however, any fractional Share shall be settled in cash. 

5.3 Duration of Options. Each Option or Stock Appreciation Right will be exercisable at such times and as specified in the Award
Agreement, provided that the term of an Option or Stock Appreciation Right will not exceed ten (10) years. Notwithstanding the foregoing and unless determined otherwise by the Company, in the event that on the last business day of the term of
an Option or Stock Appreciation Right (other than an Incentive Stock Option) (i) the exercise of the Option or Stock Appreciation Right is prohibited by Applicable Law, as determined by the Company, or (ii) Shares may not be purchased or
sold by the applicable current or former Service Provider due to any Company insider trading policy (including blackout periods) or a “lock-up” agreement undertaken in connection with an issuance of
securities by the Company, the term of the Option or Stock Appreciation Right shall be extended for a period of thirty (30) days following the end of the legal prohibition, black-out period or lock-up agreement, as determined by the Company; provided, however, in no event shall the extension last beyond the ten year term of the applicable Option or Stock Appreciation Right unless the exercise would
violate an Applicable Law. Notwithstanding the foregoing, if the Participant, prior to the end of the term of an Option or Stock Appreciation Right, violates the non-competition,
non-solicitation or confidentiality provisions of any employment contract, confidentiality and nondisclosure agreement or other agreement between the Participant and the Company or any of its Subsidiaries, the
right to exercise the Option or Stock Appreciation Right, as applicable, may, as determined by the Administrator, terminate immediately upon such violation. In addition, if, prior to the end of the term of an Option or Stock Appreciation Right, the
Participant is given notice by the Company or any of its Subsidiaries of the termination of his or her employment or other service relationship, or the employment or other service relationship is otherwise terminated for Cause, the right to exercise
the Option or Stock Appreciation Right, as applicable, shall be suspended from the time of the delivery of such notice or, in the event of other termination, as of the initiation thereof, until the earlier of (i) such time as it is determined
or otherwise agreed that the Participant’s employment or other relationship shall not be terminated for Cause or (ii) the effective date of the initiation of such termination of employment or other relationship (in which case the right to
exercise the Option or Stock Appreciation Right, as applicable, shall terminate immediately upon the effective date of such termination of employment or other service relationship). 

 5.4 Exercise. Options and Stock Appreciation Rights may be exercised by delivering to the
Company a written notice of exercise, in a form the Administrator approves (which may be electronic), signed by the person authorized to exercise the Option or Stock Appreciation Right, together with, as applicable, payment in full (i) as
specified in Section 5.5 for the number of Shares for which the Award is exercised and (ii) as specified in Section 9.4 for any applicable taxes. Unless the Administrator otherwise determines, an Option or Stock Appreciation Right may
not be exercised for a fraction of a Share. 
 5.5 Payment Upon Exercise. Subject to Section 10.7, any Company insider trading
policy (including blackout periods) and Applicable Laws, the exercise price of an Option must be paid by: 
 (a) cash, wire transfer of
immediately available funds or by check payable to the order of the Company; provided, that, the Company may limit the use of one of the foregoing exercise methods if one or more of the exercise methods below is permitted; 

(b) if there is a public market for Shares at the time of exercise, unless the Company otherwise determines, (A) delivery (including
telephonically to the extent permitted by the Company) of an irrevocable and unconditional undertaking by a broker acceptable to the Company to deliver promptly to the Company sufficient funds to pay the exercise price, or (B) the
Participant’s delivery to the Company of a copy of irrevocable and unconditional instructions to a broker acceptable to the Company to deliver promptly to the Company cash or a check sufficient to pay the exercise price; provided that such
amount is paid to the Company at such time as may be required by the Administrator; 
 (c) to the extent permitted by the Administrator,
delivery (either by actual delivery or attestation) of Shares owned by the Participant valued at their Fair Market Value; 
 (d) to the
extent permitted by the Administrator, surrendering Shares then issuable upon the Option’s exercise valued at their Fair Market Value on the exercise date; 

(e) to the extent permitted by the Administrator, delivery of a promissory note or any other property that the Administrator determines is
good and valuable consideration; or 
 (f) to the extent permitted by the Company, any combination of the above payment forms approved by
the Administrator. 
 ARTICLE VI. 

RESTRICTED STOCK; RESTRICTED STOCK UNITS 

6.1 General. With due observance of the division of authority described in Section 3.2 hereof, the Administrator may grant
Restricted Stock, or the right to purchase Restricted Stock, to any Service Provider, subject to the Company’s right to repurchase all or part of such shares at their issue price or other stated or formula price from the Participant (or to
require forfeiture of such shares) if conditions the Administrator specifies in the Award Agreement are not satisfied before the end of the applicable restriction period or periods that the Administrator establishes for such Award. In addition, the
Administrator may grant to Service Providers Restricted Stock Units, which may be subject to vesting and forfeiture conditions during the applicable restriction period or periods, as set forth in an Award Agreement. The Administrator will determine
and set forth in the Award Agreement the terms and conditions for each Restricted Stock and Restricted Stock Unit Award, subject to the conditions and limitations contained in the Plan. 

 6.2 Restricted Stock. 

(a) Dividends. Participants holding shares of Restricted Stock will be entitled to all ordinary cash dividends paid with respect to
such Shares, unless the Administrator provides otherwise in the Award Agreement. In addition, unless the Administrator provides otherwise, if any dividends or distributions are paid in Shares, or consist of a dividend or distribution to holders of
Common Stock of property other than an ordinary cash dividend, the Shares or other property will be subject to the same restrictions on transferability and forfeitability as the shares of Restricted Stock with respect to which they were paid. 

(b) Share Certificates. The Company may require that the Participant deposit in escrow with the Company (or its designee) any share
certificates issued in respect of shares of Restricted Stock, together with a share power endorsed in blank. 
 6.3 Restricted Stock
Units. 
 (a) Settlement. The Administrator may provide that settlement of Restricted Stock Units will occur upon or as soon as
reasonably practicable after the Restricted Stock Units vest or will instead be deferred, on a mandatory basis or at the Participant’s election. 

(b) Shareholder Rights. A Participant will have no rights of a shareholder with respect to Shares subject to any Restricted Stock Unit
unless and until the Shares are delivered in settlement of the Restricted Stock Unit. 
 (c) Dividend Equivalents. If the
Administrator provides, a grant of Restricted Stock Units may provide a Participant with the right to receive Dividend Equivalents. Dividend Equivalents may be paid currently or credited to an account for the Participant, settled in cash or Shares
and subject to the same restrictions on transferability and forfeitability as the Restricted Stock Units with respect to which the Dividend Equivalents are granted and subject to other terms and conditions as set forth in the Award Agreement. 

ARTICLE VII. 
 OTHER
STOCK OR CASH BASED AWARDS 
 Other Stock or Cash Based Awards may be granted to Participants, including Awards entitling Participants
to receive Shares to be delivered in the future and including annual or other periodic or longterm cash bonus awards (whether based on specified Performance Criteria or otherwise), in each case subject to any conditions and limitations in the Plan.
Such Other Stock or Cash Based Awards will also be available as a payment form in the settlement of other Awards, as standalone payments and as payment in lieu of compensation to which a Participant is otherwise entitled. Other Stock or Cash Based
Awards may be paid in Shares, cash or other property, as the Administrator determines. With due observance of the division of authority described in Section 3.2 hereof and subject to the provisions of the Plan, the Administrator will determine
the terms and conditions of each Other Stock or Cash Based Award, including any purchase price, performance goal (which may be based on the Performance Criteria), transfer restrictions, and vesting conditions, which will be set forth in the
applicable Award Agreement. 
 ARTICLE VIII. 

ADJUSTMENTS FOR CHANGES IN COMMON STOCK 

AND CERTAIN OTHER EVENTS 

8.1 Equity Restructuring. In connection with any Equity Restructuring, notwithstanding anything to the contrary in this Article VIII,
and with due observance of the division of authority described in Section 3.2 hereof, the Administrator will equitably adjust each outstanding Award as it 

 
deems appropriate to reflect the Equity Restructuring, which may include adjusting the number and type of securities subject to each outstanding Award and/or the Award’s exercise price or
grant price (if applicable), granting new Awards to Participants, and making a cash payment to Participants. The adjustments provided under this Section 8.1 will be nondiscretionary and final and binding on the affected Participant and the
Company; provided that the Administrator will determine whether an adjustment is equitable. 
 8.2 Corporate Transactions. In the
event of any spin-off, Change in Control or any change in any Applicable Laws or accounting principles, the Administrator, with due observance of the division of authority described in Section 3.2 hereof
and on such terms and conditions as it deems appropriate, either by the terms of the Award or by action taken prior to the occurrence of such transaction or event (except that action to give effect to a change in Applicable Law or accounting
principles may be made within a reasonable period of time after such change) and either automatically or upon the Participant’s request, is hereby authorized to take any one or more of the following actions whenever the Administrator determines
that such action is appropriate in order to (x) prevent dilution or enlargement of the benefits or potential benefits intended by the Company to be made available under the Plan or with respect to any Award granted or issued under the Plan,
(y) to facilitate such transaction or event or (z) give effect to such changes in Applicable Laws or accounting principles: 
 (a)
To provide for the cancellation of any such Award in exchange for either an amount of cash or other property with a value equal to the amount that could have been obtained upon the exercise or settlement of the vested portion of such Award or
realization of the Participant’s rights under the vested portion of such Award, as applicable; provided that, if the amount that could have been obtained upon the exercise or settlement of the vested portion of such Award or realization of the
Participant’s rights, in any case, is equal to or less than zero, then the Award may be terminated without payment; 
 (b) To provide
that such Award shall vest and, to the extent applicable, be exercisable as to all shares covered thereby, notwithstanding anything to the contrary in the Plan or the provisions of such Award; 

(c) To provide that such Award be assumed by the successor or survivor corporation, or a parent or subsidiary thereof, or shall be substituted
for by awards covering the stock of the successor or survivor corporation, or a parent or subsidiary thereof, with appropriate adjustments as to the number and kind of shares and/or applicable exercise or purchase price, in all cases, as determined
by the Administrator; 
 (d) To make adjustments in the number and type of shares of Common Stock (or other securities or property) subject
to outstanding Awards and/or with respect to which Awards may be granted under the Plan (including, but not limited to, adjustments of the limitations in Article IV hereof on the maximum number and kind of shares which may be issued) and/or in the
terms and conditions of (including the grant or exercise price), and the criteria included in, outstanding Awards; 
 (e) To replace such
Award with other rights or property selected by the Administrator; and/or 
 (f) To provide that the Award will terminate and cannot vest,
be exercised or become payable after the applicable event. 
 8.3 Administrative Stand Still. In the event of any pending share
dividend, share split, combination or exchange of shares, merger, consolidation or other distribution (other than normal cash 

 
dividends) of Company assets to shareholders, or any other extraordinary transaction or change affecting the Shares or the share price of Common Stock, including any Equity Restructuring or any
securities offering or other similar transaction, for administrative convenience, the Administrator, with due observance of the division of authority described in Section 3.2 hereof, may refuse to permit the exercise of any Award for up to
sixty days before or after such transaction. 
 8.4 General. Except as expressly provided in the Plan or the Administrator’s
action under the Plan, no Participant will have any rights due to any subdivision or consolidation of Shares of any class, dividend payment, increase or decrease in the number of Shares of any class or dissolution, liquidation, merger, or
consolidation of the Company or other corporation. Except as expressly provided with respect to an Equity Restructuring under Section 8.1 above or the Administrator’s action under the Plan, no issuance by the Company of Shares of any
class, or securities convertible into Shares of any class, will affect, and no adjustment will be made regarding, the number of Shares subject to an Award or the Award’s grant or exercise price. The existence of the Plan, any Award Agreements
and the Awards granted hereunder will not affect or restrict in any way the Company’s right or power to make or authorize (i) any adjustment, recapitalization, reorganization or other change in the Company’s capital structure or its
business, (ii) any merger, consolidation dissolution or liquidation of the Company or sale of Company assets or (iii) any sale or issuance of securities, including securities with rights superior to those of the Shares or securities
convertible into or exchangeable for Shares. The Administrator may treat Participants and Awards (or portions thereof) differently under this Article VIII. 

ARTICLE IX. 
 GENERAL
PROVISIONS APPLICABLE TO AWARDS 
 9.1 Transferability. Except as the Administrator may determine or provide in an Award
Agreement or otherwise for Awards, Awards may not be sold, assigned, transferred, pledged or otherwise encumbered, either voluntarily or by operation of law, except by will or the laws of descent and distribution, or, subject to the
Administrator’s consent, pursuant to a domestic relations order, and, during the life of the Participant, will be exercisable only by the Participant. References to a Participant, to the extent relevant in the context, will include references
to a Participant’s authorized transferee that the Administrator specifically approves. 
 9.2 Documentation. Each Award will be
evidenced in an Award Agreement, which may be written or electronic, as the Administrator determines. Each Award may contain terms and conditions in addition to those set forth in the Plan. 

9.3 Discretion. Except as the Plan otherwise provides, each Award may be made alone or in addition or in relation to any other Award.
The terms of each Award to a Participant need not be identical, and the Administrator need not treat Participants or Awards (or portions thereof) uniformly. 

9.4 Withholding. Each Participant must pay the Company, or make provision satisfactory to the Administrator for payment of, any taxes
required by law to be withheld in connection with such Participant’s Awards by the date of the event creating the tax liability. The Company may deduct an amount sufficient to satisfy such tax obligations based on the minimum statutory
withholding rates (or such other rate as may be determined by the Company after considering any accounting consequences or costs) from any payment of any kind otherwise due to a Participant. Subject to Section 10.7 and any Company insider
trading policy (including blackout periods), Participants may satisfy such tax obligations (i) in cash, by wire transfer of immediately available funds, by check made payable to the order of the Company; provided, that, the Company may limit
the use of one of the foregoing methods if one or more of the exercise methods below is permitted, (ii) to the extent permitted by the Administrator, in whole or in part by delivery of Shares, including Shares retained from the Award creating
the tax 

 
obligation, valued at their Fair Market Value, (iii) if there is a public market for Shares at the time the tax obligations are satisfied, unless the Company otherwise determines,
(A) delivery (including telephonically to the extent permitted by the Company) of an irrevocable and unconditional undertaking by a broker acceptable to the Company to deliver promptly to the Company sufficient funds to satisfy the tax
obligations, or (B) delivery by the Participant to the Company of a copy of irrevocable and unconditional instructions to a broker acceptable to the Company to deliver promptly to the Company cash or a check sufficient to satisfy the tax
withholding; provided that such amount is paid to the Company at such time as may be required by the Administrator, or (iv) to the extent permitted by the Company, any combination of the foregoing payment forms approved by the Administrator. If
any tax withholding obligation will be satisfied under clause (ii) of the immediately preceding sentence by the Company’s retention of Shares from the Award creating the tax obligation and there is a public market for Shares at the time
the tax obligation is satisfied, the Company may elect to instruct any brokerage firm determined acceptable to the Company for such purpose to sell on the applicable Participant’s behalf some or all of the Shares retained and to remit the
proceeds of the sale to the Company or its designee, and each Participant’s acceptance of an Award under the Plan will constitute the Participant’s authorization to the Company and instruction and authorization to such brokerage firm to
complete the transactions described in this sentence. 
 9.5 Amendment of Award; Repricing. With due observance
of the division of authority described in Section 3.2 hereof, the Administrator may amend, modify or terminate any outstanding Award, including by substituting another Award of the same or a different type, changing the exercise or settlement
date, and converting an Incentive Stock Option to a Non-Qualified Stock Option. The Participant’s consent to such action will be required unless (i) the action, taking into account any related
action, does not materially and adversely affect the Participant’s rights under the Award, or (ii) the change is permitted under Article VIII. Notwithstanding the foregoing or anything in the Plan to the contrary, the Administrator may not
except pursuant to Article VIII, without the approval of the shareholders of the Company, reduce the exercise price per share of outstanding Options or Stock Appreciation Rights or cancel outstanding Options or Stock Appreciation Rights in exchange
for cash, other Awards or Options or Stock Appreciation Rights with an exercise price per share that is less than the exercise price per share of the original Options or Stock Appreciation Rights. 

9.6 Conditions on Delivery of Shares. The Company will not be obligated to deliver any Shares under the Plan or remove restrictions
from Shares previously delivered under the Plan until (i) all Award conditions have been met or removed to the Company’s satisfaction, (ii) as determined by the Company, all other legal matters regarding the issuance and delivery of
such Shares have been satisfied, including any applicable securities laws and stock exchange or stock market rules and regulations, and (iii) the Participant has executed and delivered to the Company such representations or agreements as the
Administrator deems necessary or appropriate to satisfy any Applicable Laws. The Company’s inability to obtain authority from any regulatory body having jurisdiction, which the Administrator determines is necessary to the lawful issuance and
sale of any securities, will relieve the Company of any liability for failing to issue or sell such Shares as to which such requisite authority has not been obtained. 

9.7 Acceleration. The Administrator may at any time provide that any Award will become immediately vested and fully or partially
exercisable, free of some or all restrictions or conditions, or otherwise fully or partially realizable. 
 9.8 Cash Payments. Cash
payments made to Participants under the Plan will be made in the currency the Participant is ordinarily paid in. 

 ARTICLE X. 

MISCELLANEOUS 
 10.1 No
Right to Employment or Other Status. No person will have any claim or right to be granted an Award, and the grant of an Award will not be construed as giving a Participant the right to continued employment or any other relationship with the
Company. The Company expressly reserves the right at any time to dismiss or otherwise terminate its relationship with a Participant free from any liability or claim under the Plan or any Award, except as expressly provided in an Award Agreement.

 10.2 No Rights as Shareholder; Certificates. Subject to the Award Agreement, no Participant or Designated Beneficiary will have
any rights as a shareholder with respect to any Shares to be distributed under an Award until becoming the record holder of such Shares. Notwithstanding any other provision of the Plan, unless the Administrator otherwise determines or Applicable
Laws require, the Company will not be required to deliver to any Participant certificates evidencing Shares issued in connection with any Award and instead such Shares may be recorded in the books of the Company (or, as applicable, its transfer
agent or share plan administrator). The Company may place legends on share certificates issued under the Plan that the Administrator deems necessary or appropriate to comply with Applicable Laws. 

10.3 Effective Date and Term of Plan. Unless earlier terminated by the Management Board, subject to the approval of the Supervisory
Board, the Plan will become effective on the day prior to the Public Trading Date (the “Effective Date”) and will remain in effect until the tenth (10th) anniversary of the earlier of
(i) the date the General Meeting adopted the Plan or (ii) the date the Company’s shareholders approved the Plan, but Awards previously granted may extend beyond that date in accordance with the Plan. No Awards may be granted under the
Plan during any suspension period or after Plan termination. 
 10.4 Amendment of Plan. The Management Board, subject to the approval
of the Supervisory Board, may amend, suspend or terminate the Plan at any time; provided that no amendment, other than an increase to the Overall Share Limit, may materially and adversely affect any Award outstanding at the time of such amendment
without the affected Participant’s consent. Awards outstanding at the time of any Plan suspension or termination will continue to be governed by the Plan and the Award Agreement, as in effect before such suspension or termination. The
Administrator will obtain shareholder approval of any Plan amendment to the extent necessary to comply with the Articles or Applicable Laws. 

10.5 Provisions for Foreign Participants. The Administrator may modify Awards granted to Participants who are employed outside the
Netherlands or establish subplans or procedures under the Plan to address differences in laws, rules, regulations or customs of such foreign jurisdictions with respect to tax, securities, currency, employee benefit or other matters. 

10.6 Limitations on Liability. Notwithstanding any other provisions of the Plan, no individual acting as a director, officer, other
employee or agent of the Company or any Subsidiary will be liable to any Participant, former Participant, spouse, beneficiary, or any other person for any claim, loss, liability, or expense incurred in connection with the Plan or any Award, and such
individual will not be personally liable with respect to the Plan because of any contract or other instrument executed in his or her capacity as an Administrator, director, officer, other employee or agent of the Company or any Subsidiary. The
Company will indemnify and hold harmless each director, officer, other employee and agent of the Company or any Subsidiary that has been or will be granted or delegated any duty or power relating to the Plan’s administration or interpretation,
against any cost or expense (including attorneys’ fees) or liability (including any sum paid in settlement of a claim with the Administrator’s approval) arising from any act or omission concerning this Plan unless arising from such
person’s own fraud or bad faith. 

 10.7 Lock-Up Period. The Company may, at the
request of any underwriter representative or otherwise, in connection with registering the offering of any Company securities under the Securities Act,prohibit Participants from, directly or indirectly, selling or otherwise transferring any Shares
or other Company securities during a period of up to one hundred eighty days following the effective date of a Company registration statement filed under the Securities Act, or such longer period as determined by the underwriter. During any such
period and unless determined otherwise by the Administrator, a Participant subject to tax in the Netherlands (i) shall not sell Shares under any circumstances and may not directly or indirectly assign, transfer, pledge or otherwise encumber any
Shares or take any action to avoid the impact of such restriction, (ii) shall, at the Administrator’s request, represent to the Company that the Participant has complied with these restrictions so that the Administrator may monitor
Participant’s compliance and (iii) bear the risk of any potential decrease of the market value of the shares during the Lock-Up period. 

10.8 Data Privacy. As a condition for receiving any Award, each Participant explicitly and unambiguously consents to the collection,
use and transfer, in electronic or other form, of personal data as described in this section by and among the Company and its Subsidiaries and affiliates exclusively for, and to the extent necessary, implementing, administering and managing the
Participant’s participation in the Plan. To the extent necessary to execute and administer the Plan, the Company and its Subsidiaries and affiliates may hold certain personal information about a Participant, including the Participant’s
name, address and telephone number; birthdate; social security, insurance number or other identification number; salary; nationality; job title(s); any Shares held in the Company or its Subsidiaries and affiliates; and Award details, to implement,
manage and administer the Plan and Awards (the “Data”). The Company and any Subsidiaries and/or affiliates may transfer the Data amongst themselves to the extent necessary to implement, administer and manage a
Participant’s participation in the Plan, and the Company and its Subsidiaries and affiliates may transfer the Data to third parties assisting the Company with Plan implementation, administration and management. These recipients may be located
in the Participant’s country, or elsewhere, and the recipients’ country may be a country outside the European Union not offering adequate protection of personal data. By accepting an Award, each Participant authorizes such recipients to
receive, possess, use, retain and transfer the Data, in electronic or other form, to implement, administer and manage the Participant’s participation in the Plan, including any required Data transfer to a broker or other third party with whom
the Company or the Participant may elect to deposit any Shares. The Data related to a Participant will be held only as long as necessary to implement, administer, and manage the Participant’s participation in the Plan, and in any event no
longer than two (2) years thereafter, unless a longer storage period is required by law or governmental regulations or Company policy. A Participant may, at any time, view the Data that the Company holds, or that was sent by the Company to a
recipient, regarding such Participant, request additional information about the storage and processing of the Data regarding such Participant, request any necessary corrections to the Data regarding the Participant or refuse or withdraw the consents
in this Section 10.8 in writing, without cost, by contacting the local human resources representative. The Company may cancel Participant’s ability to participate in the Plan, including any forfeiture of any outstanding Awards, if the
Participant refuses or withdraws the consents in this Section 10.8 without any justified reason. For more information on the consequences of refusing or withdrawing consent, Participants may contact their local human resources representative.

 10.9 Severability. If any portion of the Plan or any action taken under it is held illegal or invalid for any reason, the
illegality or invalidity will not affect the remaining parts of the Plan, and the Plan will be construed and enforced as if the illegal or invalid provisions had been excluded, and the illegal or invalid action will be null and void. 

10.10 Governing Documents. If any contradiction occurs between the Plan and any Award Agreement or other written agreement between a
Participant and the Company (or any Subsidiary) that the Administrator has approved, the Plan will govern, unless it is expressly specified in such Award Agreement or other written document that a specific provision of the Plan will not apply. 

 10.11 Governing Law. The Plan and all Awards will be governed by and interpreted in
accordance with the laws of the Netherlands, disregarding any state’s choice-of-law principles requiring the application of a jurisdiction’s laws other than
the Netherlands. 
 10.12 Claw-back Provisions. All Awards (including any proceeds, gains or other economic benefit the Participant
actually or constructively receives upon receipt or exercise of any Award or the receipt or resale of any Shares underlying the Award) will be subject to any Company claw-back policy, including any claw-back policy adopted to comply with Applicable
Laws (including the Corporate Governance Code, the Dodd-Frank Wall Street Reform and Consumer Protection Act and any rules or regulations promulgated thereunder) as set forth in such claw-back policy or as a clause in the Award Agreement. 

10.13 Unilateral Amendment. The Administrator reserves the right to unilaterally amend the conditions of the Plan and/or of an Award,
subject to the restrictions of the Articles or Applicable Law. 
 10.14 Titles and Headings. The titles and headings in the Plan are
for convenience of reference only and, if any conflict, the Plan’s text, rather than such titles or headings, will control. 
 10.15
Conformity to Securities Laws. Participant acknowledges that the Plan is intended to conform to the extent necessary with Applicable Laws. Notwithstanding anything herein to the contrary, the Plan and all Awards will be administered only in
conformance with Applicable Laws. To the extent Applicable Laws permit, the Plan and all Award Agreements will be deemed amended as necessary to conform to Applicable Laws. 

10.16 Relationship to Other Benefits. No payment under the Plan will be taken into account in determining any benefits under any
pension, retirement, savings, profit sharing, group insurance, welfare or other benefit plan of the Company or any Subsidiary except as expressly provided in writing in such other plan or an agreement thereunder. 

10.17 Broker-Assisted Sales. In the event of a broker-assisted sale of Shares in connection with the payment of amounts owed by a
Participant under or with respect to the Plan or Awards, including amounts to be paid under the final sentence of Section 9.4: (a) any Shares to be sold through the broker-assisted sale will be sold on the day the payment first becomes due, or
as soon thereafter as practicable; (b) such Shares may be sold as part of a block trade with other Participants in the Plan in which all participants receive an average price; (c) the applicable Participant will be responsible for all
broker’s fees and other costs of sale, and by accepting an Award, each Participant agrees to indemnify and hold the Company harmless from any losses, costs, damages, or expenses relating to any such sale; (d) to the extent the Company or
its designee receives proceeds of such sale that exceed the amount owed, the Company will pay such excess in cash to the applicable Participant as soon as reasonably practicable; (e) the Company and its designees are under no obligation to
arrange for such sale at any particular price; and (f) in the event the proceeds of such sale are insufficient to satisfy the Participant’s applicable obligation, the Participant may be required to pay immediately upon demand to the
Company or its designee an amount in cash sufficient to satisfy any remaining portion of the Participant’s obligation. 
 ARTICLE XI.

 DEFINITIONS 
 As
used in the Plan, the following words and phrases will have the following meanings: 
 11.1 “Administrator” means
the Supervisory Board or the Management Board, subject to the division of authority set forth in Section 3.2 hereof. 

 11.2 “Applicable Laws” means the requirements relating to the
administration of equity incentive plans under the laws of the Netherlands, the applicable rules of any stock exchange or quotation system on which the Common Stock is listed or quoted and the applicable laws and rules of any foreign country or
other jurisdiction where Awards are granted. 
 11.3 “Articles” means the Articles of Association of the Company, as
amended from time to time. 
 11.4 “Award” means, individually or collectively, a grant under the Plan of Options,
Stock Appreciation Rights, Restricted Stock, Restricted Stock Units or Other Stock or Cash Based Awards. 
 11.5 “Award
Agreement” means a written agreement evidencing an Award, which may be electronic, that contains such terms and conditions as the Administrator determines, consistent with and subject to the terms and conditions of the Plan. 

11.6 “Cause” means (a) if Participant is a party to a written employment, consulting or other agreement for
service with the Company or any of its Subsidiaries or an Award Agreement in which the term “cause” is defined (a “Relevant Agreement”), “Cause” as defined in the Relevant Agreement; plus (i) an
urgent cause (dringende reden) within the meaning of Section 7:677 juncto 7:678 of the DCC; (ii) a reasonable ground within the meaning of Section 7:669, subsections 3 d, e, f, g and h of the DCC; provided, however with
respect to grounds pursuant to 7:669, subsections 3 g and h of the DCC, if such ground(s) is (are) predominantly attributable to the Participant; and (iii) if the employment, consulting or other agreement for the service of the Participant with
the Company or any of its Subsidiaries is governed by Foreign Laws, grounds which are the same or similar to those mentioned under the preceding (a)(i) and(a)(ii); or (b) if no Relevant Agreement exists, “Cause” means (i) an
urgent cause (dringende reden) within the meaning of Section 7:677 juncto 7:678 of the DCC; (ii) a reasonable ground within the meaning of Section 7:669, subsections 3 d, e, f, g and h of the DCC; provided, however with
respect to grounds pursuant to 7:669, subsections 3 g and h of the DCC, if such ground(s) is (are) predominantly attributable to the Participant; (iii) if the employment, consulting or other agreement for the service of the Participant with the
Company or any of its Subsidiaries is governed by Foreign Laws, grounds which are the same or similar to those mentioned under the preceding (b)(i) and (b)(ii); (iv) Participant’s failure to substantially perform Participant’s duties
(other than a failure resulting from Participant’s Disability); (v) Participant’s failure to carry out, or comply with any lawful and reasonable directive of the Supervisory Board, the Management Board or Participant’s immediate
supervisor; (vi) the occurrence of any act or omission by Participant that could reasonably be expected to result in (or has resulted in) Participant’s conviction, plea of no contest, plea of nolo contendere, or imposition of unadjudicated
probation for any felony or indictable offense or crime involving moral turpitude; (vii) Participant’s unlawful use (including being under the influence) or possession of illegal drugs on the premises of the Company or any of its
Subsidiaries or while performing Participant’s duties and responsibilities for the Company or any of its Subsidiaries; or (viii) Participant’s commission of an act of fraud, embezzlement, misappropriation, misconduct, or breach of
fiduciary duty against the Company or any of its Subsidiaries. 
 11.7 “Change in Control” means and includes each
of the following: 
 (a) A transaction or series of transactions (other than an offering of Common Stock to the general public through a
registration statement filed with the Securities and Exchange Commission or a transaction or series of transactions that meets the requirements of clauses (i) and (ii) of subsection (b) below) whereby any “person” or related
“group” of “persons” (as such terms are used in Sections 13(d) and 14(d)(2) of the Exchange Act) (other than the Company, any of its Subsidiaries, an employee benefit plan maintained by the Company or any of its Subsidiaries or a
“person” that, prior to such transaction, directly or indirectly controls, is controlled by, or is under common control with, the 

 
Company) directly or indirectly acquires beneficial ownership (within the meaning of Rule 13d-3 under the Exchange Act) of securities of the Company
possessing more than 50% of the total combined voting power of the Company’s securities outstanding immediately after such acquisition; or 

(b) The consummation by the Company (whether directly involving the Company or indirectly involving the Company through one or more
intermediaries) of (x) a merger, consolidation, reorganization, or business combination or (y) a sale or other disposition of all or substantially all of the Company’s assets in any single transaction or series of related transactions
or (z) the acquisition of assets or stock of another entity, in each case other than a transaction: 
 (i) which results in the
Company’s voting securities outstanding immediately before the transaction continuing to represent (either by remaining outstanding or by being converted into voting securities of the Company or the person that, as a result of the transaction,
controls, directly or indirectly, the Company or owns, directly or indirectly, all or substantially all of the Company’s assets or otherwise succeeds to the business of the Company (the Company or such person, the “Successor
Entity”)) directly or indirectly, at least a majority of the combined voting power of the Successor Entity’s outstanding voting securities immediately after the transaction, and 

(ii) after which no person or group beneficially owns voting securities representing 50% or more of the combined voting power of the
Successor Entity; provided, however, that no person or group shall be treated for purposes of this clause (ii) as beneficially owning 50% or more of the combined voting power of the Successor Entity solely as a result of the voting power
held in the Company prior to the consummation of the transaction. 
 11.8 “Code” means the Internal Revenue Code of
1986, as amended, and the regulations issued thereunder. 
 11.9 “Committee” means one or more committees or
subcommittees of the Supervisory Board or Management Board, which may include one or more members of the Supervisory Board, Management Board or executive officers, to the extent Applicable Laws permit. To the extent required to comply with the
provisions of Rule 16b-3, it is intended that each member of the Committee will be, at the time the Committee takes any action with respect to an Award that is subject to Rule
16b-3, a “non-employee director” within the meaning of Rule 16b-3; however, a Committee member’s failure to
qualify as a “non-employee director” within the meaning of Rule 16b-3 will not invalidate any Award granted by the Committee that is otherwise validly granted
under the Plan. 
 11.10 “Common Stock” means the common shares of the Company within the meaning of the Articles.

 11.11 “Company” means Merus N.V., a Dutch public, limited liability company. 

11.12 “Consultant” means any person, other than an Employee, or a member of the Management Board or Supervisory Board,
including any adviser, engaged directly or indirectly by the Company and/or any Subsidiary to render services to the Company and/or Subsidiary if such person: (i) renders bona fide services to the Company; (ii) renders services not in
connection with the offer or sale of securities in a capital-raising transaction and does not directly or indirectly promote or maintain a market for the Company’s securities; and (iii) is a natural person. 

11.13 “DCC” means the Dutch Civil Code. 

 11.14 “Designated Beneficiary” means the beneficiary or beneficiaries of
the Participant designated pursuant to Applicable Laws, to receive amounts due or exercise the Participant’s rights if the Participant dies or becomes incapacitated. 

11.15 “Disability” means disability to perform work due to sickness within the meaning of Section 7:629
subsection 1 of the DCC or if the relevant agreement of a Service Provider is governed by Foreign Laws, the equivalent of Section7:629 subsection 1 of the DCC under such Foreign Laws. 

11.16 “Dividend Equivalents” means a right granted to a Participant under the Plan to receive the equivalent value (in
cash or Shares) of dividends paid on Shares. 
 11.17 “Employee” means any employee of the Company or its
Subsidiaries within the meaning of Applicable Laws. 
 11.18 “Equity Restructuring” means a nonreciprocal
transaction between the Company and its shareholders, such as a share dividend, share split, spin-off or recapitalization through a large, nonrecurring cash dividend, that affects the number or kind of Shares
(or other Company securities) or the share price of Common Stock (or other Company securities) and causes a change in the per share value of the Common Stock underlying outstanding Awards. 

11.19 “Exchange Act” means the United States Securities Exchange Act of 1934, as amended. 

11.20 “Fair Market Value” means, as of any date, the value of Common Stock determined as follows: (i) if the
Common Stock is listed on any established stock exchange, its Fair Market Value will be the closing sales price for such Common Stock as quoted on such exchange for such date, or if no sale occurred on such date, the last day preceding such date
during which a sale occurred, as reported in The Wall Street Journal or another source the Administrator deems reliable; (ii) if the Common Stock is not traded on a stock exchange but is quoted on a national market or other quotation system,
the closing sales price on such date, or if no sales occurred on such date, then on the last date preceding such date during which a sale occurred, as reported in The Wall Street Journal or another source the Administrator deems reliable; or
(iii) without an established market for the Common Stock, the Administrator will determine the Fair Market Value in its discretion. 

11.21 “Foreign Laws” means the laws of any jurisdiction other than the laws of the Netherlands. 

11.22 “Incentive Stock Option” means an Option intended to qualify as an “incentive stock option” as defined
in Section 422 of the Code. 
 11.23 “Management Board” means the management board (bestuur) of the
Company within the meaning of the Articles. 
 11.24 “Management Board Rules of Procedure” means the Merus N.V.
Rules of Procedure for the Management Board. 
 11.25 “Non-Qualified Stock
Option” means an Option not intended or not qualifying as an Incentive Stock Option. 
 11.26 “Option”
means an option to purchase Shares. 

 11.27 “Other Stock or Cash Based Awards” means cash awards, awards of
Shares, and other awards valued wholly or partially by referring to, or are otherwise based on, Shares or other property. 
 11.28
“Overall Share Limit” means the sum of (i) 1,277,778 Shares and (ii) an annual increase on the first day of each calendar year beginning January 1, 2017 and ending on and including January 1, 2026, equal to the
least of (A) 4% of the aggregate number of shares of Common Stock outstanding on the final day of the immediately preceding calendar year and (B) such smaller number of Shares as is determined by the Supervisory Board. 

11.29 “Participant” means a Service Provider who has been granted an Award. 

11.30 “Performance Criteria” mean the criteria (and adjustments) that the Administrator may select for an Award to
establish performance goals for a performance period, which may include the following: net earnings or losses (either before or after one or more of interest, taxes, depreciation, amortization, and non-cash
equity-based compensation expense); gross or net sales or revenue or sales or revenue growth; net income (either before or after taxes) or adjusted net income; profits (including but not limited to gross profits, net profits, profit growth, net
operation profit or economic profit), profit return ratios or operating margin; budget or operating earnings (either before or after taxes or before or after allocation of corporate overhead and bonus); cash flow (including operating cash flow and
free cash flow or cash flow return on capital); return on assets; return on capital or invested capital; cost of capital; return on shareholders’ equity; total shareholder return; return on sales; costs, reductions in costs and cost control
measures; expenses; working capital; earnings or loss per share; adjusted earnings or loss per share; price per share or dividends per share (or appreciation in or maintenance of such price or dividends); regulatory achievements or compliance;
implementation, completion or attainment of objectives relating to research, development, regulatory, commercial, or strategic milestones or developments; market share; economic value or economic value added models; division, group or corporate
financial goals; customer satisfaction/growth; customer service; employee satisfaction; recruitment and maintenance of personnel; human resources management; supervision of litigation and other legal matters; strategic partnerships and transactions;
financial ratios (including those measuring liquidity, activity, profitability or leverage); debt levels or reductions; sales-related goals; financing and other capital raising transactions; cash on hand; acquisition activity; investment sourcing
activity; and marketing initiatives, any of which may be measured in absolute terms or as compared to any incremental increase or decrease. Such performance goals also may be based solely by reference to the Company’s performance or the
performance of a Subsidiary, division, business segment or business unit of the Company or a Subsidiary, or based upon performance relative to performance of other companies or upon comparisons of any of the indicators of performance relative to
performance of other companies. The Committee may provide for exclusion of the impact of an event or occurrence which the Committee determines should appropriately be excluded, including (a) restructurings, discontinued operations,
extraordinary items, and other unusual, infrequently occurring or non-recurring charges or events, (b) asset write-downs, (c) litigation or claim judgments or settlements, (d) acquisitions or
divestitures, (e) reorganization or change in the corporate structure or capital structure of the Company, (f) an event either not directly related to the operations of the Company, Subsidiary, division, business segment or business unit
or not within the reasonable control of management, (g) foreign exchange gains and losses, (h) a change in the fiscal year of the Company, (i) the refinancing or repurchase of bank loans or debt securities, (j) unbudgeted capital
expenditures, (k) the issuance or repurchase of equity securities and other changes in the number of outstanding shares, (l) conversion of some or all of convertible securities to Common Stock, (m) any business interruption event
(n) the cumulative effects of tax or accounting changes in accordance with U.S. generally accepted accounting principles, or (o) the effect of changes in other laws or regulatory rules affecting reported results. 

11.31 “Plan” means this 2016 Incentive Award Plan. 

 11.32 “Prior Plans” means, collectively, the Merus B.V. 2010 Employee
Option Plan and any prior equity incentive plans of the Company or its predecessor. 
 11.33 “Prior Plan Award”
means an award outstanding under the Prior Plans as of the Plan’s effective date in Section 10.3. 
 11.34 “Public
Trading Date” means the first date upon which the Common Stock is listed (or approved for listing) upon notice of issuance on any securities exchange or designated (or approved for designation) upon notice of issuance as a national
market security on an interdealer quotation system, or, if earlier, the date on which the Company becomes a “publicly held corporation” for purposes of Treasury Regulation
Section 1.162-27(c)(1). 
 11.35 “Restricted Stock” means Shares
awarded to a Participant under Article VI subject to certain vesting conditions and other restrictions. 
 11.36 “Restricted
Stock Unit” means an unfunded, unsecured right to receive, on the applicable settlement date, one Share or an amount in cash or other consideration determined by the Administrator to be of equal value as of such settlement date, subject
to certain vesting conditions and other restrictions. 
 11.37 “Rule 16b-3”
means Rule 16b-3 promulgated under the Exchange Act. 
 11.38 “Securities
Act” means the Securities Act of 1933, as amended. 
 11.39 “Service Provider” means an Employee,
Consultant or member of the Management Board or the Supervisory Board. 
 11.40 “Shares” means shares of Common
Stock. 
 11.41 “Stock Appreciation Right” means a stock appreciation right granted under Article V. 

11.42 “Subsidiary” means a subsidiary (dochtermaatschappij) within the meaning of Section 2:24a of the DCC.

 11.43 “Substitute Awards” shall mean Awards granted or Shares issued by the Company in assumption of, or in
substitution or exchange for, awards previously granted, or the right or obligation to make future awards, in each case by a company acquired by the Company or any Subsidiary or with which the Company or any Subsidiary combines. 

11.44 “Supervisory Board” means the supervisory board (raad van commissarissen) of the Company within the
meaning of the Articles. 
 11.45 “Termination of Service” means the date the Participant ceases to be a Service
Provider. 
 * * * * * 

 ANNEXES: 
  

	1.	UNITED STATES ADDENDUM 

  

	2.	OPTION AGREEMENT 

  

	3.	RESTRICTED STOCK AGREEMENT 

  

	4.	RSU AGREEMENT 

 MERUS N.V. 

2016 INCENTIVE AWARD PLAN 

UNITED STATES ADDENDUM 

Capitalized terms not specifically defined in this United States Addendum (the “US Addendum”)
have the meanings given to them in the 2016 Incentive Award Plan (as amended from time to time, the “Plan”) of Merus N.V. (the “Company”). 

Pursuant to Section 10.5 of the Plan, the Administrator has adopted this US Addendum which contains additional terms and conditions of
the Plan applicable to Participants residing in the United States. To the extent not impacted by this US Addendum, the Plan shall remain unchanged and in full force and effect according to its terms. 

ARTICLE XII. 
 INCENTIVE
STOCK OPTIONS 
 12.1 Incentive Stock Option Limitations. Notwithstanding anything to the contrary in the Plan, no more than
1,277,778 Shares may be issued pursuant to the exercise of Incentive Stock Options. 
 12.2 Terms of Incentive Stock Options. The
Administrator may grant Incentive Stock Options only to employees of the Company, any of its present or future parent or subsidiary corporations, as defined in Sections 424(e) or (f) of the Code, respectively, and any other entities the
employees of which are eligible to receive Incentive Stock Options under the Code. If an Incentive Stock Option is granted to a Greater Than 10% Shareholder, the exercise price will not be less than 110% of the Fair Market Value on the Option’s
grant date, and the term of the Option will not exceed five years. All Incentive Stock Options will be subject to and construed consistently with Section 422 of the Code. By accepting an Incentive Stock Option, the Participant agrees to give
prompt notice to the Company of dispositions or other transfers (other than in connection with a Change in Control) of Shares acquired under the Option made within (i) two years from the grant date of the Option or (ii) one year after the
transfer of such Shares to the Participant, specifying the date of the disposition or other transfer and the amount the Participant realized, in cash, other property, assumption of indebtedness or other consideration, in such disposition or other
transfer. Neither the Company nor the Administrator will be liable to a Participant, or any other party, if an Incentive Stock Option fails or ceases to qualify as an “incentive stock option” under Section 422 of the Code. Any
Incentive Stock Option or portion thereof that fails to qualify as an “incentive stock option” under Section 422 of the Code for any reason, including becoming exercisable with respect to Shares having a fair market value exceeding
the $100,000 limitation under Treasury Regulation Section 1.422-4, will be a Non-Qualified Stock Option. 

ARTICLE XIII. 
 SECTION
409A 
 13.1 General. The Company intends that all Awards be structured to comply with, or be exempt from, Section 409A, such
that no adverse tax consequences, interest, or penalties under Section 409A apply. Notwithstanding anything in the Plan or any Award Agreement to the contrary, the Administrator may, without a Participant’s consent, amend the Plan, this US
Addendum or Awards, adopt policies and procedures, or take any other actions (including amendments, policies, procedures and retroactive actions) as are necessary or appropriate to preserve the intended tax treatment of Awards, including any such
actions intended to (A) exempt the Plan, this US Addendum or any Award from Section 409A, or (B) comply with Section 409A, including regulations, guidance, compliance programs 

 
and other interpretative authority that may be issued after an Award’s grant date. The Company makes no representations or warranties as to an Award’s tax treatment under Section 409A
or otherwise. The Company will have no obligation under this Section 2.1 or otherwise to avoid the taxes, penalties or interest under Section 409A with respect to any Award and will have no liability to any Participant or any other person if
any Award, compensation or other benefits under the Plan are determined to constitute noncompliant “nonqualified deferred compensation” subject to taxes, penalties or interest under Section 409A. 

13.2 Separation from Service. If an Award constitutes “nonqualified deferred compensation” under Section 409A, any payment or
settlement of such Award upon a termination of a Participant’s Service Provider relationship will, to the extent necessary to avoid taxes under Section 409A, be made only upon the Participant’s “separation from service” (within
the meaning of Section 409A), whether such “separation from service” occurs upon or after the termination of the Participant’s Service Provider relationship. For purposes of the Plan, this US Addendum or any Award Agreement relating
to any such payments or benefits, references to a “termination,” “termination of employment” or like terms means a “separation from service.” 

13.3 Payments to Specified Employees. Notwithstanding any contrary provision in the Plan, this US Addendum or any Award Agreement, any
payment(s) of “nonqualified deferred compensation” required to be made under an Award to a “specified employee” (as defined under Section 409A and as the Administrator determines) due to his or her “separation from
service” will, to the extent necessary to avoid taxes under Section 409A(a)(2)(B)(i) of the Code, be delayed for the six-month period immediately following such “separation from service” (or, if
earlier, until the specified employee’s death) and will instead be paid (as set forth in the Award Agreement) on the day immediately following such six-month period or as soon as administratively
practicable thereafter (without interest). Any payments of “nonqualified deferred compensation” under such Award payable more than six months following the Participant’s “separation from service” will be paid at the time or
times the payments are otherwise scheduled to be made. 
 13.4 Change in Control. 

(a) Notwithstanding the definition of “Change in Control” contained in Section 11.7 of the Plan, if a Change in Control
constitutes a payment event with respect to any Award (or portion of any Award) that provides for the deferral of compensation that is subject to Section 409A, to the extent required to avoid the imposition of additional taxes under Section 409A,
the transaction or event described in subsection (a) or (b) of Section 11.7 of the Plan with respect to such Award (or portion thereof) shall only constitute a Change in Control for purposes of the payment timing of such Award if such
transaction also constitutes a “change in control event,” as defined in Treasury Regulation Section 1.409A-3(i)(5). 

(b) The Administrator shall have full and final authority, which shall be exercised in its discretion, to determine conclusively whether a
Change in Control has occurred pursuant to the above definition, the date of the occurrence of such Change in Control and any incidental matters relating thereto; provided that any exercise of authority in conjunction with a determination of whether
a Change in Control is a “change in control event” as defined in Treasury Regulation Section 1.409A-3(i)(5) shall be consistent with such regulation. 

13.5 Restricted Stock Units. Pursuant to Section 6.3(a) of the Plan, the Administrator may provide that settlement of Restricted Stock
Units will occur upon or as soon as reasonably practicable after the Restricted Stock Units vest or will instead be deferred, on a mandatory basis or at the Participant’s election; provided, that the Administrator shall make such determination
in a manner intended to comply with Section 409A. 

 ARTICLE XIV. 

DEFINITIONS 
 14.1
“Greater Than 10% Shareholder” means an individual then owning (within the meaning of Section 424(d) of the Code) more than 10% of the total combined voting power of all share classes of the Company or
its parent or subsidiary corporation, as defined in Section 424(e) and (f) of the Code, respectively. 
 14.2
“Section 409A” means Section 409A of the Code and all regulations, guidance, compliance programs and other interpretative authority thereunder. 

* * * * * 

 MERUS N.V. 

2016 INCENTIVE AWARD PLAN 
 STOCK
OPTION GRANT NOTICE 
 Capitalized terms not specifically defined in this Stock Option Grant Notice (the “Grant
Notice”) have the meanings given to them in the 2016 Incentive Award Plan (as amended from time to time, the “Plan”) of Merus N.V. (the
“Company”). 
 The Company has granted to the participant listed below
(“Participant”) the stock option described in this Grant Notice (the “Option”), subject to the terms and conditions of the Plan and the Stock Option Agreement
attached as Exhibit A (the “Agreement”), both of which are incorporated into this Grant Notice by reference. 
  

			
	 Participant:
	  	
		
	 Grant Date:
	  	
		
	 Exercise Price per Share:
	  	
		
	 Shares Subject to the Option:
	  	
		
	 Final Expiration Date:
	  	
		
	Vesting Commencement Date:	  	
		
	Vesting Schedule:	  	[To be specified in individual award agreements]

 By Participant’s signature below, Participant agrees to be bound by the terms of this Grant Notice, the
Plan and the Agreement. Participant has reviewed the Plan, this Grant Notice and the Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Grant Notice and fully understands all provisions of the
Plan, this Grant Notice and the Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan, this Grant Notice or the Agreement. 

 

							
	PARTIES:	 		 	
			
	MERUS N.V.	 		 	PARTICIPANT
				
	By:	 	  
	 		 	  

				
	Name:	 	  
	 		 	[Participant Name]
				
	Title:	 	  
	 		 	

 STOCK OPTION AGREEMENT 

Capitalized terms not specifically defined in this Agreement have the meanings specified in the Grant Notice or, if not defined in the Grant
Notice, in the Plan. 
 ARTICLE XV. 

GENERAL 
 15.1 Grant of Option.
The Company has granted to Participant the Option effective as of the grant date set forth in the Grant Notice (the “Grant Date”). 

15.2 Incorporation of Terms of Plan. The Option is subject to the terms and conditions set forth in this Agreement and the Plan, which is
incorporated herein by reference. In the event of any inconsistency between the Plan and this Agreement, the terms of the Plan will control. 

ARTICLE XVI. 
 PERIOD OF
EXERCISABILITY 
 16.1 Commencement of Exercisability. The Option will vest and become exercisable according to the vesting schedule in the
Grant Notice (the “Vesting Schedule”) except that any fraction of a Share as to which the Option would be vested or exercisable will be accumulated and will vest and become exercisable only when a whole
Share has accumulated. Notwithstanding anything in the Grant Notice, the Plan or this Agreement to the contrary, unless the Administrator otherwise determines, the Option will immediately expire and be forfeited as to any portion that is not vested
and exercisable as of Participant’s Termination of Service for any reason. 
 16.2 Duration of Exercisability. The Vesting Schedule is
cumulative. Any portion of the Option which vests and becomes exercisable will remain vested and exercisable until the Option expires. The Option will be forfeited immediately upon its expiration. 

16.3 Expiration of Option. The Option may not be exercised to any extent by anyone after, and will expire on, the first of the following to
occur: 
 (a) The final expiration date in the Grant Notice; 

(b) Except as the Administrator may otherwise approve, the expiration of three (3) months from the date of Participant’s Termination
of Service, unless Participant’s Termination of Service is for Cause or by reason of Participant’s death or Disability; 
 (c)
Except as the Administrator may otherwise approve, the expiration of one (1) year from the date of Participant’s Termination of Service by reason of Participant’s death or Disability; and 

(d) Except as the Administrator may otherwise approve, Participant’s Termination of Service for Cause or the initiation of such
Termination of Service by giving notice of termination, by requesting termination by the court or otherwise (e.g. a written proposal for termination by mutual consent). 

 ARTICLE XVII. 

EXERCISE OF OPTION 
 17.1 Person
Eligible to Exercise. During Participant’s lifetime, only Participant may exercise the Option. After Participant’s death, any exercisable portion of the Option may, prior to the time the Option expires, be exercised by Participant’s
Designated Beneficiary as provided in the Plan. 
 17.2 Partial Exercise. Any exercisable portion of the Option or the entire Option, if
then wholly exercisable, may be exercised, in whole or in part, according to the procedures in the Plan at any time prior to the time the Option or portion thereof expires, except that the Option may only be exercised for whole Shares. 

17.3 Tax Withholding. 
 (a) The
Company has the right and option, but not the obligation, to treat Participant’s failure to provide timely payment in accordance with the Plan of any withholding tax arising in connection with the Option as Participant’s election to
satisfy all or any portion of the withholding tax by requesting the Company retain Shares otherwise issuable under the Option. 
 (b)
Participant acknowledges that Participant is ultimately liable and responsible for all taxes owed in connection with the Option, regardless of any action the Company or any Subsidiary takes with respect to any tax withholding obligations that arise
in connection with the Option. Neither the Company nor any Subsidiary makes any representation or undertaking regarding the treatment of any tax withholding in connection with the awarding, vesting or exercise of the Option or the subsequent sale of
Shares. The Company and the Subsidiaries do not commit and are under no obligation to structure the Option to reduce or eliminate Participant’s tax liability. 

ARTICLE XVIII. 
 OTHER PROVISIONS

 18.1 Adjustments. Participant acknowledges that the Option is subject to adjustment, modification and termination in certain events as
provided in this Agreement and the Plan. 
 18.2 Notices. Any notice to be given under the terms of this Agreement to the Company must be in
writing and addressed to the Company in care of the Company’s Secretary at the Company’s principal office or the Secretary’s then-current email address or facsimile number. Any notice to be given under the terms of this Agreement to
Participant must be in writing and addressed to Participant (or, if Participant is then deceased, to the person entitled to exercise the Option) at Participant’s last known mailing address, email address or facsimile number in the
Company’s personnel files. By a notice given pursuant to this Section, either party may designate a different address for notices to be given to that party. Any notice will be deemed duly given when actually received, when sent by email, when
sent by certified mail (return receipt requested) and deposited with postage prepaid in a post office or branch post office regularly maintained by the United States Postal Service, when delivered by a nationally recognized express shipping company
or upon receipt of a facsimile transmission confirmation. 
 18.3 Titles. Titles are provided herein for convenience only and are not to
serve as a basis for interpretation or construction of this Agreement. 
 18.4 Conformity to Securities Laws. Participant acknowledges that
the Plan, the Grant Notice and this Agreement are intended to conform to the extent necessary with all Applicable Laws and, to the extent Applicable Laws permit, will be deemed amended as necessary to conform to Applicable Laws. 

 18.5 Successors and Assigns. The Company may assign any of its rights under this Agreement to
single or multiple assignees, and this Agreement will inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer set forth in the Plan, this Agreement will be binding upon and inure to the benefit of
the heirs, legatees, legal representatives, successors and assigns of the parties hereto. 
 18.6 Limitations Applicable to Section 16
Persons. Notwithstanding any other provision of the Plan or this Agreement, if Participant is subject to Section 16 of the Exchange Act, the Plan, the Grant Notice, this Agreement and the Option will be subject to any additional limitations set
forth in any applicable exemptive rule under Section 16 of the Exchange Act (including any amendment to Rule 16b-3) that are requirements for the application of such exemptive rule. To the extent
Applicable Laws permit, this Agreement will be deemed amended as necessary to conform to such applicable exemptive rule. 
 18.7 Entire
Agreement. The Plan, the Grant Notice and this Agreement (including any exhibit hereto) constitute the entire agreement of the parties and supersede in their entirety all prior undertakings and agreements of the Company and Participant with respect
to the subject matter hereof. 
 18.8 Agreement Severable. In the event that any provision of the Grant Notice or this Agreement is held
illegal or invalid, the provision will be severable from, and the illegality or invalidity of the provision will not be construed to have any effect on, the remaining provisions of the Grant Notice or this Agreement. 

18.9 Limitation on Participant’s Rights. Participation in the Plan confers no rights or interests other than as herein provided. This
Agreement creates only a contractual obligation on the part of the Company as to amounts payable and may not be construed as creating a trust. Neither the Plan nor any underlying program, in and of itself, has any assets. Participant will have only
the rights of a general unsecured creditor of the Company with respect to amounts credited and benefits payable, if any, with respect to the Option, and rights no greater than the right to receive the Shares as a general unsecured creditor with
respect to the Option, as and when exercised pursuant to the terms hereof. 
 18.10 Not a Contract of Employment. Nothing in the Plan, the
Grant Notice or this Agreement confers upon Participant any right to continue in the employ or service of the Company or any Subsidiary or interferes with or restricts in any way the rights of the Company and its Subsidiaries, which rights are
hereby expressly reserved, to discharge or terminate the services of Participant at any time for any reason whatsoever, with or without Cause, except to the extent expressly provided otherwise in a written agreement between the Company or a
Subsidiary and Participant. 
 18.11 Claw-back. The Administrator may, in its sole reasonable discretion, deem the outcome of a remuneration
component granted to the Participant under this Agreement unreasonable either because the same has been based on incorrect information (including but not limited to financial information) or in light of special circumstances. In such cases, the
Administrator is entitled to adjust such component up- or downwards. If, in the event of such downward adjustment, the Options have already been exercised, the Company is entitled to reclaim what payments
consequential to such downward adjustment was unduly paid either in cash compensation or in Shares. 
 18.12 Counterparts. The Grant Notice
may be executed in one or more counterparts, including by way of any electronic signature, subject to Applicable Law, each of which will be deemed an original and all of which together will constitute one instrument. 

* * * * * 

 MERUS N.V. 

2016 INCENTIVE AWARD PLAN 

RESTRICTED STOCK GRANT NOTICE 

Capitalized terms not specifically defined in this Restricted Stock Grant Notice (the “Grant
Notice”) have the meanings given to them in the 2016 Incentive Award Plan (as amended from time to time, the “Plan”) of Merus N.V. (the
“Company”). 
 The Company has granted to the participant listed below
(“Participant”) the shares of Restricted Stock described in this Grant Notice (the “Restricted Shares”), subject to the terms and conditions of the Plan and
the Restricted Stock Agreement attached as Exhibit A (the “Agreement”), both of which are incorporated into this Grant Notice by reference. 

 

			
	Participant:	  	
		
	Grant Date:	  	
		
	Number of Restricted Shares:	  	
		
	Vesting Commencement Date:	  	
		
	Vesting Schedule:	  	[To be specified in individual award agreements]

 By Participant’s signature below, Participant agrees to be bound by the terms of this Grant Notice, the
Plan and the Agreement. Participant has reviewed the Plan, this Grant Notice and the Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Grant Notice and fully understands all provisions of the
Plan, this Grant Notice and the Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan, this Grant Notice or the Agreement. 

 

							
	PARTIES:	 		 		 	
			
	MERUS N.V.	 		 	PARTICIPANT
				
	By:	 	  
	 		 	  

				
	Name:	 	  
	 		 	[Participant Name]
				
	Title:	 	  
	 		 	

 RESTRICTED STOCK AGREEMENT 

Capitalized terms not specifically defined in this Agreement have the meanings specified in the Grant Notice or, if not defined in the Grant
Notice, in the Plan. 
 ARTICLE XIX. 

GENERAL 
 19.1 Issuance of
Restricted Shares. The Company will issue the Restricted Shares to the Participant effective as of the grant date set forth in the Grant Notice and will cause (a) a stock certificate or certificates representing the Restricted Shares to be
registered in Participant’s name or (b) the Restricted Shares to be held in book-entry form. If a stock certificate is issued, the certificate will be delivered to, and held in accordance with this Agreement by, the Company or its
authorized representatives and will bear the restrictive legends required by this Agreement. If the Restricted Shares are held in book-entry form, then the book-entry will indicate that the Restricted Shares are subject to the restrictions of this
Agreement. 
 19.2 Incorporation of Terms of Plan. The Restricted Shares are subject to the terms and conditions set forth in this Agreement
and the Plan, which is incorporated herein by reference. In the event of any inconsistency between the Plan and this Agreement, the terms of the Plan will control. 

ARTICLE XX. 
 VESTING, FORFEITURE
AND ESCROW 
 20.1 Vesting. The Restricted Shares will become vested Shares (the “Vested
Shares”) according to the vesting schedule in the Grant Notice except that any fraction of a Share that would otherwise become a Vested Share will be accumulated and will become a Vested Share only when a whole Vested Share
has accumulated. 
 20.2 Forfeiture. In the event of Participant’s Termination of Service for any reason, Participant will immediately
and automatically forfeit to the Company any Shares that are not Vested Shares (the “Unvested Shares”) at the time of Participant’s Termination of Service, except as otherwise determined by the
Administrator or provided in a binding written agreement between Participant and the Company. Upon forfeiture of Unvested Shares, the Company will become the legal and beneficial owner of the Unvested Shares and all related interests and Participant
will have no further rights with respect to the Unvested Shares. 
 20.3 Escrow. 

(a) Unvested Shares will be held by the Company or its authorized representatives until (i) they are forfeited, (ii) they become
Vested Shares or (iii) this Agreement is no longer in effect. By accepting this Award, Participant appoints the Company and its authorized representatives as Participant’s
attorney(s)-in-fact to take all actions necessary to effect any transfer of forfeited Unvested Shares (and Retained Distributions (as defined below), if any, paid on
such forfeited Unvested Shares) to the Company as may be required pursuant to the Plan or this Agreement and to execute such representations or other documents or assurances as the Company or such representatives deem necessary or advisable in
connection with any such transfer. The Company, or its authorized representative, will not be liable for any good faith act or omission with respect to the holding in escrow or transfer of the Restricted Shares. 

 (b) All cash dividends and other distributions made or declared with respect to Unvested Shares
(“Retained Distributions”) will be held by the Company until the time (if ever) when the Unvested Shares to which such Retained Distributions relate become Vested Shares. The Company will establish a
separate Retained Distribution bookkeeping account (“Retained Distribution Account”) for each Unvested Share with respect to which Retained Distributions have been made or declared in cash and credit the
Retained Distribution Account (without interest) on the date of payment with the amount of such cash made or declared with respect to the Unvested Share. Retained Distributions (including any Retained Distribution Account balance) will immediately
and automatically be forfeited upon forfeiture of the Unvested Share with respect to which the Retained Distributions were paid or declared. 

(c) As soon as reasonably practicable following the date on which an Unvested Share becomes a Vested Share, the Company will (i) cause
the certificate (or a new certificate without the legend required by this Agreement, if Participant so requests) representing the Share to be delivered to Participant or, if the Share is held in book-entry form, cause the notations indicating the
Share is subject to the restrictions of this Agreement to be removed and (ii) pay to Participant the Retained Distributions relating to the Share. 

20.4 Rights as Stockholder. Except as otherwise provided in this Agreement or the Plan, upon issuance of the Restricted Shares by the Company,
Participant will have all the rights of a stockholder with respect to the Restricted Shares, including the right to vote the Restricted Shares and to receive dividends or other distributions paid or made with respect to the Restricted Shares. 

ARTICLE XXI. 
 TAXATION AND TAX
WITHHOLDING 
 21.1 Representation. Participant represents to the Company that Participant has reviewed with Participant’s own tax
advisors the tax consequences of the Restricted Shares and the transactions contemplated by the Grant Notice and this Agreement. Participant is relying solely on such advisors and not on any statements or representations of the Company or any of its
agents. 
 21.2 Tax Withholding. 

(a) The Company has the right and option, but not the obligation, to treat Participant’s failure to provide timely payment in accordance
with the Plan of any withholding tax arising in connection with the Restricted Shares as Participant’s election to satisfy all or any portion of the withholding tax by requesting the Company retain Shares otherwise deliverable under the Award.

 (b) Participant acknowledges that Participant is ultimately liable and responsible for all taxes owed in connection with the Restricted
Shares, regardless of any action the Company or any Subsidiary takes with respect to any tax withholding obligations that arise in connection with the Restricted Shares. Neither the Company nor any Subsidiary makes any representation or undertaking
regarding the treatment of any tax withholding in connection with the awarding, vesting or payment of the Restricted Shares or the subsequent sale of the Restricted Shares. The Company and the Subsidiaries do not commit and are under no obligation
to structure this Award to reduce or eliminate Participant’s tax liability. 
 ARTICLE XXII. 

RESTRICTIVE LEGENDS AND TRANSFERABILITY 

22.1 Legends. Any certificate representing a Restricted Share will bear the following legend until the Restricted Share becomes a Vested
Share: 
 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO FORFEITURE IN FAVOR OF THE COMPANY AND MAY BE TRANSFERRED ONLY IN
ACCORDANCE WITH THE TERMS OF A RESTRICTED STOCK AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 

 22.2 Transferability. The Restricted Shares and any Retained Distributions are subject to the
restrictions on transfer in the Plan and may not be sold, assigned or transferred in any manner unless and until they become Vested Shares. Any attempted transfer or disposition of Unvested Shares or related Retained Distributions prior to the time
the Unvested Shares become Vested Shares will be null and void. The Company will not be required to (a) transfer on its books any Restricted Share that has been sold or otherwise transferred in violation of this Agreement or (b) treat as
owner of such Restricted Share or accord the right to vote or pay dividends to any purchaser or other transferee to whom such Restricted Share has been so transferred. The Company may issue appropriate “stop transfer” instructions to its
transfer agent, if any, or make appropriate notations to the same effect in its records. 
 ARTICLE XXIII. 

OTHER PROVISIONS 
 23.1
Adjustments. Participant acknowledges that the Restricted Shares are subject to adjustment, modification and termination in certain events as provided in this Agreement and the Plan. 

23.2 Notices. Any notice to be given under the terms of this Agreement to the Company must be in writing and addressed to the Company in care
of the Company’s Secretary at the Company’s principal office or the Secretary’s then-current email address or facsimile number. Any notice to be given under the terms of this Agreement to Participant must be in writing and addressed
to Participant at Participant’s last known mailing address, email address or facsimile number in the Company’s personnel files. By a notice given pursuant to this Section, either party may designate a different address for notices to be
given to that party. Any notice will be deemed duly given when actually received, when sent by email, when sent by certified mail (return receipt requested) and deposited with postage prepaid in a post office or branch post office regularly
maintained by the United States Postal Service, when delivered by a nationally recognized express shipping company or upon receipt of a facsimile transmission confirmation. 

23.3 Titles. Titles are provided herein for convenience only and are not to serve as a basis for interpretation or construction of this
Agreement. 
 23.4 Conformity to Securities Laws. Participant acknowledges that the Plan, the Grant Notice and this Agreement are intended
to conform to the extent necessary with all Applicable Laws and, to the extent Applicable Laws permit, will be deemed amended as necessary to conform to Applicable Laws. 

23.5 Successors and Assigns. The Company may assign any of its rights under this Agreement to single or multiple assignees, and this Agreement
will inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer set forth in this Agreement or the Plan, this Agreement will be binding upon and inure to the benefit of the heirs, legatees, legal
representatives, successors and assigns of the parties hereto. 

 23.6 Limitations Applicable to Section 16 Persons. Notwithstanding any other provision of
the Plan or this Agreement, if Participant is subject to Section 16 of the Exchange Act, the Plan, the Grant Notice, this Agreement and the Restricted Shares will be subject to any additional limitations set forth in any applicable exemptive
rule under Section 16 of the Exchange Act (including any amendment to Rule 16b-3) that are requirements for the application of such exemptive rule. To the extent Applicable Laws permit, this Agreement
will be deemed amended as necessary to conform to such applicable exemptive rule. 
 23.7 Entire Agreement. The Plan, the Grant Notice and
this Agreement (including any exhibit hereto) constitute the entire agreement of the parties and supersede in their entirety all prior undertakings and agreements of the Company and Participant with respect to the subject matter hereof. 

23.8 Agreement Severable. In the event that any provision of the Grant Notice or this Agreement is held illegal or invalid, the provision will
be severable from, and the illegality or invalidity of the provision will not be construed to have any effect on, the remaining provisions of the Grant Notice or this Agreement. 

23.9 Limitation on Participant’s Rights. Participation in the Plan confers no rights or interests other than as herein provided. This
Agreement creates only a contractual obligation on the part of the Company as to amounts payable and may not be construed as creating a trust. Neither the Plan nor any underlying program, in and of itself, has any assets. Participant will have only
the rights of a general unsecured creditor of the Company with respect to amounts credited and benefits payable, if any, with respect to the Award. 

23.10 Not a Contract of Employment. Nothing in the Plan, the Grant Notice or this Agreement confers upon Participant any right to continue in
the employ or service of the Company or any Subsidiary or interferes with or restricts in any way the rights of the Company and its Subsidiaries, which rights are hereby expressly reserved, to discharge or terminate the services of Participant at
any time for any reason whatsoever, with or without cause, except to the extent expressly provided otherwise in a written agreement between the Company or a Subsidiary and Participant. 

23.11 Claw-back. The Administrator may, in its sole reasonable discretion, deem the outcome of a remuneration component granted to the
Participant under this Agreement unreasonable either because the same has been based on incorrect information (including but not limited to financial information) or in light of special circumstances. In such cases, the Administrator is entitled to
adjust such component up- or downwards. If, in the event of such downward adjustment, payment in Shares and/or in cash has already been made by the Company to the Participant, the Company is entitled to
reclaim what payments consequential to such downward adjustment was unduly paid. 
 23.12 Counterparts. The Grant Notice may be executed in
one or more counterparts, including by way of any electronic signature, subject to Applicable Law, each of which will be deemed an original and all of which together will constitute one instrument. 

* * * * * 

 MERUS N.V. 

2016 INCENTIVE AWARD PLAN 

RESTRICTED STOCK GRANT NOTICE 

Capitalized terms not specifically defined in this Restricted Stock Grant Notice (the “Grant Notice”) have the meanings given
to them in the 2016 Incentive Award Plan (as amended from time to time, the “Plan”) of Merus N.V. (the “Company”). 

The Company has granted to the participant listed below (“Participant”) the shares of Restricted Stock described in this
Grant Notice (the “Restricted Shares”), subject to the terms and conditions of the Plan and the Restricted Stock Agreement attached as Exhibit A (the “Agreement”), both of which are incorporated into this Grant
Notice by reference. 
  

			
	 Participant:
	  	
		
	 Grant Date:
	  	
		
	 Number of Restricted Shares:
	  	
		
	 Vesting Commencement Date:
	  	
		
	Vesting Schedule:	  	[To be specified in individual award agreements]

 By Participant’s signature below, Participant agrees to be bound by the terms of this Grant Notice, the
Plan and the Agreement. Participant has reviewed the Plan, this Grant Notice and the Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Grant Notice and fully understands all provisions of the
Plan, this Grant Notice and the Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan, this Grant Notice or the Agreement. 

 

					
	PARTIES:	  		  	
			
	MERUS N.V.	  		  	PARTICIPANT

  

							
	By:	 	  
	 		  	  

				
	Name:	 	  
	 		  	[Participant Name]
				
	Title:	 	  
	 		  	

 RESTRICTED STOCK AGREEMENT 

Capitalized terms not specifically defined in this Agreement have the meanings specified in the Grant Notice or, if not defined in the Grant
Notice, in the Plan. 
 ARTICLE XXIV. 

GENERAL 
 24.1 Issuance of
Restricted Shares. The Company will issue the Restricted Shares to the Participant effective as of the grant date set forth in the Grant Notice and will cause (a) a stock certificate or certificates representing the Restricted Shares to be
registered in Participant’s name or (b) the Restricted Shares to be held in book-entry form. If a stock certificate is issued, the certificate will be delivered to, and held in accordance with this Agreement by, the Company or its
authorized representatives and will bear the restrictive legends required by this Agreement. If the Restricted Shares are held in book-entry form, then the book-entry will indicate that the Restricted Shares are subject to the restrictions of this
Agreement. 
 24.2 Incorporation of Terms of Plan. The Restricted Shares are subject to the terms and conditions set forth in this Agreement
and the Plan, which is incorporated herein by reference. In the event of any inconsistency between the Plan and this Agreement, the terms of the Plan will control. 

ARTICLE XXV. 
 VESTING, FORFEITURE
AND ESCROW 
 25.1 Vesting. The Restricted Shares will become vested Shares (the “Vested Shares”) according to the vesting
schedule in the Grant Notice except that any fraction of a Share that would otherwise become a Vested Share will be accumulated and will become a Vested Share only when a whole Vested Share has accumulated. 

25.2 Forfeiture. In the event of Participant’s Termination of Service for any reason, Participant will immediately and automatically
forfeit to the Company any Shares that are not Vested Shares (the “Unvested Shares”) at the time of Participant’s Termination of Service, except as otherwise determined by the Administrator or provided in a binding written
agreement between Participant and the Company. Upon forfeiture of Unvested Shares, the Company will become the legal and beneficial owner of the Unvested Shares and all related interests and Participant will have no further rights with respect to
the Unvested Shares. 
 25.3 Escrow. 

(a) Unvested Shares will be held by the Company or its authorized representatives until (i) they are forfeited, (ii) they become
Vested Shares or (iii) this Agreement is no longer in effect. By accepting this Award, Participant appoints the Company and its authorized representatives as Participant’s
attorney(s)-in-fact to take all actions necessary to effect any transfer of forfeited Unvested Shares (and Retained Distributions (as defined below), if any, paid on
such forfeited Unvested Shares) to the Company as may be required pursuant to the Plan or this Agreement and to execute such representations or other documents or assurances as the Company or such representatives deem necessary or advisable in
connection with any such transfer. The Company, or its authorized representative, will not be liable for any good faith act or omission with respect to the holding in escrow or transfer of the Restricted Shares. 

 (b) All cash dividends and other distributions made or declared with respect to Unvested Shares
(“Retained Distributions”) will be held by the Company until the time (if ever) when the Unvested Shares to which such Retained Distributions relate become Vested Shares. The Company will establish a separate Retained Distribution
bookkeeping account (“Retained Distribution Account”) for each Unvested Share with respect to which Retained Distributions have been made or declared in cash and credit the Retained Distribution Account (without interest) on the
date of payment with the amount of such cash made or declared with respect to the Unvested Share. Retained Distributions (including any Retained Distribution Account balance) will immediately and automatically be forfeited upon forfeiture of the
Unvested Share with respect to which the Retained Distributions were paid or declared. 
 (c) As soon as reasonably practicable following
the date on which an Unvested Share becomes a Vested Share, the Company will (i) cause the certificate (or a new certificate without the legend required by this Agreement, if Participant so requests) representing the Share to be delivered to
Participant or, if the Share is held in book-entry form, cause the notations indicating the Share is subject to the restrictions of this Agreement to be removed and (ii) pay to Participant the Retained Distributions relating to the Share. 

25.4 Rights as Stockholder. Except as otherwise provided in this Agreement or the Plan, upon issuance of the Restricted Shares by the Company,
Participant will have all the rights of a stockholder with respect to the Restricted Shares, including the right to vote the Restricted Shares and to receive dividends or other distributions paid or made with respect to the Restricted Shares. 

ARTICLE XXVI. 
 TAXATION AND TAX
WITHHOLDING 
 26.1 Representation. Participant represents to the Company that Participant has reviewed with Participant’s own tax
advisors the tax consequences of the Restricted Shares and the transactions contemplated by the Grant Notice and this Agreement. Participant is relying solely on such advisors and not on any statements or representations of the Company or any of its
agents. 
 26.2 Tax Withholding. 

(a) The Company has the right and option, but not the obligation, to treat Participant’s failure to provide timely payment in accordance
with the Plan of any withholding tax arising in connection with the Restricted Shares as Participant’s election to satisfy all or any portion of the withholding tax by requesting the Company retain Shares otherwise deliverable under the Award.

 (b) Participant acknowledges that Participant is ultimately liable and responsible for all taxes owed in connection with the Restricted
Shares, regardless of any action the Company or any Subsidiary takes with respect to any tax withholding obligations that arise in connection with the Restricted Shares. Neither the Company nor any Subsidiary makes any representation or undertaking
regarding the treatment of any tax withholding in connection with the awarding, vesting or payment of the Restricted Shares or the subsequent sale of the Restricted Shares. The Company and the Subsidiaries do not commit and are under no obligation
to structure this Award to reduce or eliminate Participant’s tax liability. 
 ARTICLE XXVII. 

RESTRICTIVE LEGENDS AND TRANSFERABILITY 

27.1 Legends. Any certificate representing a Restricted Share will bear the following legend until the Restricted Share becomes a Vested
Share: 
 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO FORFEITURE IN FAVOR OF THE COMPANY AND MAY BE TRANSFERRED ONLY IN
ACCORDANCE WITH THE TERMS OF A RESTRICTED STOCK AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 

 27.2 Transferability. The Restricted Shares and any Retained Distributions are subject to the
restrictions on transfer in the Plan and may not be sold, assigned or transferred in any manner unless and until they become Vested Shares. Any attempted transfer or disposition of Unvested Shares or related Retained Distributions prior to the time
the Unvested Shares become Vested Shares will be null and void. The Company will not be required to (a) transfer on its books any Restricted Share that has been sold or otherwise transferred in violation of this Agreement or (b) treat as
owner of such Restricted Share or accord the right to vote or pay dividends to any purchaser or other transferee to whom such Restricted Share has been so transferred. The Company may issue appropriate “stop transfer” instructions to its
transfer agent, if any, or make appropriate notations to the same effect in its records. 
 ARTICLE XXVIII. 

OTHER PROVISIONS 
 28.1
Adjustments. Participant acknowledges that the Restricted Shares are subject to adjustment, modification and termination in certain events as provided in this Agreement and the Plan. 

28.2 Notices. Any notice to be given under the terms of this Agreement to the Company must be in writing and addressed to the Company in care
of the Company’s Secretary at the Company’s principal office or the Secretary’s then-current email address or facsimile number. Any notice to be given under the terms of this Agreement to Participant must be in writing and addressed
to Participant at Participant’s last known mailing address, email address or facsimile number in the Company’s personnel files. By a notice given pursuant to this Section, either party may designate a different address for notices to be
given to that party. Any notice will be deemed duly given when actually received, when sent by email, when sent by certified mail (return receipt requested) and deposited with postage prepaid in a post office or branch post office regularly
maintained by the United States Postal Service, when delivered by a nationally recognized express shipping company or upon receipt of a facsimile transmission confirmation. 

28.3 Titles. Titles are provided herein for convenience only and are not to serve as a basis for interpretation or construction of this
Agreement. 
 28.4 Conformity to Securities Laws. Participant acknowledges that the Plan, the Grant Notice and this Agreement are intended
to conform to the extent necessary with all Applicable Laws and, to the extent Applicable Laws permit, will be deemed amended as necessary to conform to Applicable Laws. 

28.5 Successors and Assigns. The Company may assign any of its rights under this Agreement to single or multiple assignees, and this Agreement
will inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer set forth in this Agreement or the Plan, this Agreement will be binding upon and inure to the benefit of the heirs, legatees, legal
representatives, successors and assigns of the parties hereto. 

 28.6 Limitations Applicable to Section 16 Persons. Notwithstanding any other provision of
the Plan or this Agreement, if Participant is subject to Section 16 of the Exchange Act, the Plan, the Grant Notice, this Agreement and the Restricted Shares will be subject to any additional limitations set forth in any applicable exemptive
rule under Section 16 of the Exchange Act (including any amendment to Rule 16b-3) that are requirements for the application of such exemptive rule. To the extent Applicable Laws permit, this Agreement
will be deemed amended as necessary to conform to such applicable exemptive rule. 
 28.7 Entire Agreement. The Plan, the Grant Notice and
this Agreement (including any exhibit hereto) constitute the entire agreement of the parties and supersede in their entirety all prior undertakings and agreements of the Company and Participant with respect to the subject matter hereof. 

28.8 Agreement Severable. In the event that any provision of the Grant Notice or this Agreement is held illegal or invalid, the provision will
be severable from, and the illegality or invalidity of the provision will not be construed to have any effect on, the remaining provisions of the Grant Notice or this Agreement. 

28.9 Limitation on Participant’s Rights. Participation in the Plan confers no rights or interests other than as herein provided. This
Agreement creates only a contractual obligation on the part of the Company as to amounts payable and may not be construed as creating a trust. Neither the Plan nor any underlying program, in and of itself, has any assets. Participant will have only
the rights of a general unsecured creditor of the Company with respect to amounts credited and benefits payable, if any, with respect to the Award. 

28.10 Not a Contract of Employment. Nothing in the Plan, the Grant Notice or this Agreement confers upon Participant any right to continue in
the employ or service of the Company or any Subsidiary or interferes with or restricts in any way the rights of the Company and its Subsidiaries, which rights are hereby expressly reserved, to discharge or terminate the services of Participant at
any time for any reason whatsoever, with or without cause, except to the extent expressly provided otherwise in a written agreement between the Company or a Subsidiary and Participant. 

28.11 Claw-back. The Administrator may, in its sole reasonable discretion, deem the outcome of a remuneration component granted to the
Participant under this Agreement unreasonable either because the same has been based on incorrect information (including but not limited to financial information) or in light of special circumstances. In such cases, the Administrator is entitled to
adjust such component up- or downwards. If, in the event of such downward adjustment, payment in Shares and/or in cash has already been made by the Company to the Participant, the Company is entitled to
reclaim what payments consequential to such downward adjustment was unduly paid. 
 28.12 Counterparts. The Grant Notice may be executed in
one or more counterparts, including by way of any electronic signature, subject to Applicable Law, each of which will be deemed an original and all of which together will constitute one instrument. 

* * * * * 

 MERUS N.V. 

2016 INCENTIVE AWARD PLAN 

RESTRICTED STOCK UNIT GRANT NOTICE 

Capitalized terms not specifically defined in this Restricted Stock Unit Grant Notice (the “Grant Notice”) have the meanings
given to them in the 2016 Incentive Award Plan (as amended from time to time, the “Plan”) of Merus N.V. (the “Company”). 

The Company has granted to the participant listed below (“Participant”) the Restricted Stock Units described in this Grant
Notice (the “RSUs”), subject to the terms and conditions of the Plan and the Restricted Stock Unit Agreement attached as Exhibit A (the “Agreement”), both of which are incorporated into this Grant Notice by
reference. 
  

			
	 Participant:
	  	
		
	 Grant Date:
	  	
		
	 Number of RSUs:
	  	
		
	 Vesting Commencement Date:
	  	
		
	Vesting Schedule:	  	[To be specified in individual award agreements]

 By Participant’s signature below, Participant agrees to be bound by the terms of this Grant Notice, the
Plan and the Agreement. Participant has reviewed the Plan, this Grant Notice and the Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Grant Notice and fully understands all provisions of the
Plan, this Grant Notice and the Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan, this Grant Notice or the Agreement. 

 

					
	PARTIES:	  		  	
			
	MERUS N.V.	  		  	PARTICIPANT

  

							
	By:	 	  
	 		  	  

				
	Name:	 	  
	 		  	 [Participant Name]

				
	Title:	 	  
	 		  	

 RESTRICTED STOCK UNIT AGREEMENT 

Capitalized terms not specifically defined in this Agreement have the meanings specified in the Grant Notice or, if not defined in the Grant
Notice, in the Plan. 
 ARTICLE XXIX. 

GENERAL 
 29.1 Award of RSUs and
Dividend Equivalents. 
 (a) The Company has granted the RSUs to Participant effective as of the grant date set forth in the Grant Notice
(the “Grant Date”). Each RSU represents the right to receive one Share or, at the option of the Company, an amount of cash, in either case, as set forth in this Agreement. Participant will have no right to the distribution of any
Shares or payment of any cash until the time (if ever) the RSUs have vested. 
 (b) The Company hereby grants to Participant, with respect
to each RSU, a Dividend Equivalent for ordinary cash dividends paid to substantially all holders of outstanding Shares with a record date after the Grant Date and prior to the date the applicable RSU is settled, forfeited or otherwise expires. Each
Dividend Equivalent entitles Participant to receive the equivalent value of any such ordinary cash dividends paid on a single Share. The Company will establish a separate Dividend Equivalent bookkeeping account (a “Dividend Equivalent
Account”) for each Dividend Equivalent and credit the Dividend Equivalent Account (without interest) on the applicable dividend payment date with the amount of any such cash paid. 

29.2 Incorporation of Terms of Plan. The RSUs are subject to the terms and conditions set forth in this Agreement and the Plan, which is
incorporated herein by reference. In the event of any inconsistency between the Plan and this Agreement, the terms of the Plan will control. 

29.3 Unsecured Promise. The RSUs and Dividend Equivalents will at all times prior to settlement represent an unsecured Company obligation
payable only from the Company’s general assets. 
 ARTICLE XXX. 

VESTING; FORFEITURE AND SETTLEMENT 

30.1 Vesting; Forfeiture. The RSUs will vest according to the vesting schedule in the Grant Notice except that any fraction of an RSU that
would otherwise be vested will be accumulated and will vest only when a whole RSU has accumulated. In the event of Participant’s Termination of Service for any reason, all unvested RSUs will immediately and automatically be cancelled and
forfeited, except as otherwise determined by the Administrator or provided in a binding written agreement between Participant and the Company. Dividend Equivalents (including any Dividend Equivalent Account balance) will vest or be forfeited, as
applicable, upon the vesting or forfeiture of the RSU with respect to which the Dividend Equivalent (including the Dividend Equivalent Account) relates. 

30.2 Settlement. 
 (a) RSUs and
Dividend Equivalents (including any Dividend Equivalent Account balance) will be paid in Shares or cash at the Company’s option as soon as administratively practicable after the vesting of the applicable RSU, but in no event more than sixty
(60) days after the RSU’s vesting date. Notwithstanding the foregoing, the Company may delay any payment under this Agreement that the Company reasonably determines would violate Applicable Law until the earliest date the Company

  
 11 

 
reasonably determines the making of the payment will not cause such a violation (in accordance with Treasury Regulation Section 1.409A-2(b)(7)(ii)),
provided the Company reasonably believes the delay will not result in the imposition of excise taxes under Section 409A. 
 (b) If an RSU is
paid in cash, the amount of cash paid with respect to the RSU will equal the Fair Market Value of a Share on the day immediately preceding the payment date. If a Dividend Equivalent is paid in Shares, the number of Shares paid with respect to the
Dividend Equivalent will equal the quotient, rounded down to the nearest whole Share, of the Dividend Equivalent Account balance divided by the Fair Market Value of a Share on the day immediately preceding the payment date. 

ARTICLE XXXI. 
 TAXATION AND TAX
WITHHOLDING 
 31.1 Representation. Participant represents to the Company that Participant has reviewed with Participant’s own tax
advisors the tax consequences of this Award and the transactions contemplated by the Grant Notice and this Agreement. Participant is relying solely on such advisors and not on any statements or representations of the Company or any of its agents.

 31.2 Tax Withholding. 
 (a)
The Company has the right and option, but not the obligation, to treat Participant’s failure to provide timely payment in accordance with the Plan of any withholding tax arising in connection with the RSUs or Dividend Equivalents as
Participant’s election to satisfy all or any portion of the withholding tax by requesting the Company retain Shares otherwise issuable under the Award. 

(b) Participant acknowledges that Participant is ultimately liable and responsible for all taxes owed in connection with the RSUs and the
Dividend Equivalents, regardless of any action the Company or any Subsidiary takes with respect to any tax withholding obligations that arise in connection with the RSUs or Dividend Equivalents. Neither the Company nor any Subsidiary makes any
representation or undertaking regarding the treatment of any tax withholding in connection with the awarding, vesting or payment of the RSUs or the Dividend Equivalents or the subsequent sale of Shares. The Company and the Subsidiaries do not commit
and are under no obligation to structure the RSUs or Dividend Equivalents to reduce or eliminate Participant’s tax liability. 
 ARTICLE
XXXII. 
 OTHER PROVISIONS 

32.1 Adjustments. Participant acknowledges that the RSUs, the Shares subject to the RSUs and the Dividend Equivalents are subject to
adjustment, modification and termination in certain events as provided in this Agreement and the Plan. 
 32.2 Notices. Any notice to be
given under the terms of this Agreement to the Company must be in writing and addressed to the Company in care of the Company’s Secretary at the Company’s principal office or the Secretary’s then-current email address or facsimile
number. Any notice to be given under the terms of this Agreement to Participant must be in writing and addressed to Participant at Participant’s last known mailing address, email address or facsimile number in the Company’s personnel
files. By a notice given pursuant to this Section, either party may designate a different address for notices to be given to that party. Any notice will be deemed duly given when actually received, when sent by email, when sent by certified mail
(return receipt requested) and deposited with postage prepaid in a post office or branch post office regularly maintained by the United States Postal Service, when delivered by a nationally recognized express shipping company or upon receipt of a
facsimile transmission confirmation. 

  
 12 

 32.3 Titles. Titles are provided herein for convenience only and are not to serve as a basis for
interpretation or construction of this Agreement. 
 32.4 Conformity to Securities Laws. Participant acknowledges that the Plan, the Grant
Notice and this Agreement are intended to conform to the extent necessary with all Applicable Laws and, to the extent Applicable Laws permit, will be deemed amended as necessary to conform to Applicable Laws. 

32.5 Successors and Assigns. The Company may assign any of its rights under this Agreement to single or multiple assignees, and this Agreement
will inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer set forth in the Plan, this Agreement will be binding upon and inure to the benefit of the heirs, legatees, legal representatives,
successors and assigns of the parties hereto. 
 32.6 Limitations Applicable to Section 16 Persons. Notwithstanding any other provision
of the Plan or this Agreement, if Participant is subject to Section 16 of the Exchange Act, the Plan, the Grant Notice, this Agreement, the RSUs and the Dividend Equivalents will be subject to any additional limitations set forth in any
applicable exemptive rule under Section 16 of the Exchange Act (including any amendment to Rule 16b-3) that are requirements for the application of such exemptive rule. To the extent Applicable Laws
permit, this Agreement will be deemed amended as necessary to conform to such applicable exemptive rule. 
 32.7 Entire Agreement. The Plan,
the Grant Notice and this Agreement (including any exhibit hereto) constitute the entire agreement of the parties and supersede in their entirety all prior undertakings and agreements of the Company and Participant with respect to the subject matter
hereof. 
 32.8 Agreement Severable. In the event that any provision of the Grant Notice or this Agreement is held illegal or invalid, the
provision will be severable from, and the illegality or invalidity of the provision will not be construed to have any effect on, the remaining provisions of the Grant Notice or this Agreement. 

32.9 Limitation on Participant’s Rights. Participation in the Plan confers no rights or interests other than as herein provided. This
Agreement creates only a contractual obligation on the part of the Company as to amounts payable and may not be construed as creating a trust. Neither the Plan nor any underlying program, in and of itself, has any assets. Participant will have only
the rights of a general unsecured creditor of the Company with respect to amounts credited and benefits payable, if any, with respect to the RSUs and Dividend Equivalents, and rights no greater than the right to receive cash or the Shares as a
general unsecured creditor with respect to the RSUs and Dividend Equivalents, as and when settled pursuant to the terms of this Agreement. 

32.10 Not a Contract of Employment. Nothing in the Plan, the Grant Notice or this Agreement confers upon Participant any right to continue in
the employ or service of the Company or any Subsidiary or interferes with or restricts in any way the rights of the Company and its Subsidiaries, which rights are hereby expressly reserved, to discharge or terminate the services of Participant at
any time for any reason whatsoever, with or without Cause, except to the extent expressly provided otherwise in a written agreement between the Company or a Subsidiary and Participant. 

  
 13 

 32.11 Claw-back. The Administrator may, in its sole reasonable discretion, deem the outcome of a
remuneration component granted to the Participant under this Agreement unreasonable either because the same has been based on incorrect information (including but not limited to financial information) or in light of special circumstances. In such
cases, the Administrator is entitled to adjust such component up- or downwards. If, in the event of such downward adjustment, payment in Shares and/or in cash has already been made by the Company to the
Participant, the Company is entitled to reclaim what payments consequential to such downward adjustment was unduly paid. 
 32.12
Counterparts. The Grant Notice may be executed in one or more counterparts, including by way of any electronic signature, subject to Applicable Law, each of which will be deemed an original and all of which together will constitute one instrument.

 * * * * * 

  
 14EX-4.3

 Exhibit 4.3 

MERUS N.V. 

SUPERVISORY BOARD MEMBER COMPENSATION PROGRAM 

Members of the Supervisory Board (the “Supervisory Board”) of Merus N.V. (the “Company”) shall
receive cash and equity compensation as set forth in this Supervisory Board Member Compensation Program (this “Program”). The compensation described in this Program shall be paid or be made, as applicable, automatically and
without further action of the Supervisory Board or the shareholders of the Company (the “Shareholders”) with respect to the cash compensation and subject to approval by our Shareholders with respect to the equity
compensation, to each member of the Supervisory Board (each, a “Supervisory Board Member”) who is entitled to receive such cash or equity compensation, unless such Supervisory Board Member declines the receipt of such cash or
equity compensation by written notice to the Company. This Program shall remain in effect until it is revised or rescinded by further action taken by the Shareholders. This Program may be amended, modified or terminated by action taken by the
Shareholders at any time in their sole discretion. The terms and conditions of this Program shall supersede any prior cash and/or equity compensation arrangements for service as a Supervisory Board Member between the Company and any of its
Supervisory Board Members. This Program shall become effective on the date of the effectiveness of the Company’s Registration Statement on Form F-1 relating to the initial public offering of common shares (the “Effective
Date”). 
  

	I.	CASH COMPENSATION 

 A. Annual Retainers. Each
Supervisory Board Member shall receive an annual retainer of $35,000 for service on the Supervisory Board. 
 B. Additional Annual
Retainers. In addition, each Supervisory Board Member shall receive the following annual retainers: 
 1. Chairperson of the
Supervisory Board. A Supervisory Board Member serving as Chairperson of the Supervisory Board shall receive an additional annual retainer of $28,000 for such service. 

2. Audit Committee. A Supervisory Board Member serving as Chairperson of the Audit Committee shall receive an additional annual
retainer of $15,000 for such service. A Supervisory Board Member serving as a member other than the Chairperson of the Audit Committee shall receive an additional annual retainer of $7,500 for such service. 

3. Compensation Committee. A Supervisory Board Member serving as Chairperson of the Compensation Committee shall receive an additional
annual retainer of $10,000 for such service. A Supervisory Board Member serving as a member other than the Chairperson of the Compensation Committee shall receive an additional annual retainer of $5,000 for such service. 

4. Nominating and Corporate Governance Committee. A Supervisory Board Member serving as Chairperson of the Nominating and Corporate
Governance Committee shall receive an additional annual retainer of $7,500 for such service. A Supervisory Board Member serving as a member other than the Chairperson of the Nominating and Corporate Governance Committee shall receive an additional
annual retainer of $3,750 for such service. 

 C. Payment of Retainers. The annual retainers described in Sections I(A) and I(B) shall be
earned on a quarterly basis based on a calendar quarter and shall be paid in cash by the Company in arrears not later than the fifteenth day following the end of each calendar quarter. In the event a Supervisory Board Member does not serve as a
Supervisory Board Member, or in the applicable positions described in Section I(B), for an entire calendar quarter, the retainer paid to such Supervisory Board Member shall be prorated for the portion of such calendar quarter actually served as a
Supervisory Board Member, or in such position, as applicable. 
 D. Annual Increase. Each annual retainer described in Sections I(A)
and I(B) shall, without further action taken by the Shareholders, automatically increase on the first day of each calendar year beginning on January 1, 2017 by an amount equal to 3% of the value of such annual retainer in effect as of the
immediately preceding calendar year. 
  

	II.	EQUITY COMPENSATION 

 Supervisory Board Members shall be
eligible to be granted the equity awards described below. The awards described below shall be granted under and shall be subject to the terms and provisions of the Company’s 2016 Incentive Award Plan or any other applicable Company equity
incentive plan then-maintained by the Company (the “Equity Plan”) and shall be granted subject to award agreements in substantially the form previously approved by the Shareholders. All applicable terms of the Equity Plan
apply to this Program as if fully set forth herein, and all grants of stock options hereby are subject in all respects to the terms of the Equity Plan and the applicable award agreement. 

A. Initial Awards. Each Supervisory Board Member who is initially elected or appointed to the Supervisory Board after the
Effective Date shall be eligible to receive an option to purchase the number of common shares of the Company having an aggregate Grant Date Fair Value (as defined below) of $200,000, with any partial shares that result being rounded down to the
nearest whole share. The awards described in this Section II(A) shall be referred to as “Initial Awards.” No Supervisory Board Member shall be granted more than one Initial Award. “Grant Date Fair
Value” shall mean the value of the option as of the date of grant, which value shall be determined using a Black-Scholes option pricing model and the valuation assumptions used by the Company in accounting for options as of such date;
provided, that the fair market value of the common shares of the Company used in such calculation shall be based on the average trading price of the common shares of the Company over the preceding thirty day period. 

B. Subsequent Awards. A Supervisory Board Member who (i) has been serving as a Supervisory Board Member for at least six months as
of the date of any annual meeting of the Shareholders after the Effective Date and (ii) will continue to serve as a Supervisory Board Member immediately following such meeting, is eligible to be granted, at the occasion of or as soon as
practically possible following such annual meeting an option to purchase the number of common shares of the Company having an aggregate Grant Date Fair 

 
Value of $100,000, with any partial shares that result being rounded down to the nearest whole share. The awards described in this Section II(B) shall be referred to as “Subsequent
Awards.” For the avoidance of doubt, a Supervisory Board Member elected for the first time to the Supervisory Board at an annual meeting of the Shareholders shall only receive an Initial Award in connection with such election, and shall
not receive any Subsequent Award on the date of such meeting as well. 
 For the avoidance of doubt, any grant of Initial Awards and
Subsequent Awards under this Program will require a written notice of acceptance of the relevant Supervisory Board Member, in the absence of which such Supervisory Board Member will be deemed to have waived its rights to such a grant. 

C. Terms of Awards Granted to Supervisory Board Members 

1. Exercise Price. The per share exercise price of each option granted to a Supervisory Board Member shall equal the Fair Market Value
(as defined in the Equity Plan) of a common share of the Company on the date the option is granted. 
 2. Vesting. Each Initial Award
shall vest and become exercisable as to 33% of the shares subject to such Initial Award on the first anniversary of the date of grant and in 24 substantially equal monthly installments thereafter, such that the Initial Award shall be fully vested on
the third anniversary of the date of grant, subject to the Supervisory Board Member continuing in service as a Supervisory Board Member through each such vesting date. Each Subsequent Award shall vest and become exercisable in 12 substantially equal
monthly installments following the date of grant, such that the Subsequent Award shall be fully vested on the first anniversary of the date of grant, subject to the Supervisory Board Member continuing in service on the Supervisory Board as a
Supervisory Board Member through each such vesting date. Any portion of an Initial Award or Subsequent Award which is unvested or unexercisable at the time of a Supervisory Board Member’s termination of service on the Supervisory Board shall be
immediately forfeited upon such termination of service and shall not thereafter become vested and exercisable. All of a Supervisory Board Member’s Initial Awards and Subsequent Awards shall vest in full immediately prior to the occurrence of a
Change in Control (as defined in the Equity Plan), to the extent outstanding at such time. 
 3. Term. The maximum term of each stock
option granted to a Supervisory Board Member hereunder shall be ten (10) years from the date the option is granted. 
 D. Annual
Increase; Award Limit. The Grant Date Fair Value of each Initial Award and Subsequent Award described in Sections II(A) and II(B) shall, subject to approval by the Shareholders, increase on the first day of each calendar year beginning on
January 1, 2017 by an amount equal to 3% of the Grant Date Fair Value applicable to Initial Awards and Subsequent Awards in effect as of the immediately preceding calendar year; provided, that, in no event shall the number of shares awarded
pursuant to (i) an Initial Award exceed 17,000 common shares of the Company and (ii) a Subsequent Award exceed 8,500 common shares of the Company, in each case, subject to adjustment as provided in the Equity Plan, including without
limitation with respect to any share dividend, share split, reverse share split or other similar event affecting the common shares of the Company that is effected prior to the Effective Date. 

 E. Tax deductions. To the extent required to comply with applicable tax laws, the Company
shall be allowed to make necessary deductions on any compensation payable under this Program, including (without limitation) for purposes of any payroll tax or income tax. 

F. Prevailing terms. In the event of any inconsistency between the terms of the Merus N.V. 2016 Incentive Award Plan and this Program,
the terms of this Program shall prevail. 
 * * * * *

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