Form of market stock unit award agreement under the Biogen Inc. 2017 Omnibus Equity Plan (for grants commencing in July 2019)

Pursuant to the Biogen Inc. 2017 Omnibus Equity Plan (as it may be amended from time to time, the “Plan”), Biogen Inc. (the “Company”) hereby grants to you, an employee of the Company or one of its Affiliates (the “Participant”), on each of the grant dates specified on your Fidelity stock plan account (the “Grant Date”), the number of market stock units (the “Granted MSUs” or the “Award”) specified on your Fidelity stock plan account, subject to the terms and conditions of this award agreement (“Agreement”) and the Plan. No MSU shall be paid unless vested in accordance with this Agreement. The Participant’s rights to the Granted MSUs are subject to the restrictions described in this Agreement and the Plan, in addition to such other restrictions, if any, as may be imposed by law. All initially capitalized terms used herein will have the meaning specified in the Plan, unless another meaning is specified in this Agreement.

A.The Participant shall have a non-forfeitable right to a portion of the Award only upon the vesting dates specified on your Fidelity stock plan account, except as otherwise provided herein or determined by the Committee in its sole discretion. Except as provided in Section 2.C. or 2.D. below, no portion of any Award shall become eligible to vest on the vesting date unless the Participant is then, and since the Grant Date has continuously been, employed by the Company or any Affiliate. If the Participant ceases to be employed by the Company and its Affiliates for any reason, any then outstanding and unvested portion of the Award shall be automatically and immediately forfeited and terminated, except as otherwise provided in this Agreement and the Plan.

B.(i) The Award will become eligible to vest in in three equal installments on each of the first, second and third anniversaries of the Grant Date (each a “Vesting Date” and collectively, the “Vesting Period”).

(i)On each Vesting Date, the number of MSUs that become eligible to vest on such Vesting Date will vest based upon the change in the Company’s share price between the Vesting Date and the Grant Date. The calculation of the number of Granted MSUs that will vest is specified in the Long-Term Incentive Program Overview for Executives for the year in which the Award is granted (“LTI Overview”), which is also found on your Fidelity stock plan account. In the event and to the extent that a number of the Granted MSUs then eligible to vest do not vest on the applicable Vesting Date in accordance with this Agreement and the LTI Overview, such Granted MSUs shall be immediately forfeited. In the event and to the extent that the target is exceeded based on the calculation described in the LTI Overview, an additional number of Granted MSUs will vest. In no event shall the number of Granted MSUs that vest on the applicable Vesting Date exceed 200% of the Granted MSUs that became eligible to vest on such Vesting Date.

C.In the event of a Corporate Change in Control, subject to the Participant’s continued employment with the Company and its Affiliates through the date of such Corporate Change in Control:

(i)the Committee shall determine the extent to which all then outstanding and unvested Granted MSUs would vest based solely on the Company’s share price in connection with the Corporate Change in Control (determined as if the date of the Corporate Change in Control were the Vesting Date for such Granted MSUs, and not, for the avoidance of doubt, taking into account the Company’s share price during any trailing thirty (30)-day period) and, that number of the

Granted MSUs that does not vest based on such share price in accordance with this Agreement and the LTI Overview shall be immediately forfeited;

(ii)to the extent the acquiring or surviving entity assumes, continues or substitutes for any then outstanding Granted MSUs (determined after giving effect to clause (i) above) in connection with the Corporate Change in Control, the Granted MSUs (including any Granted MSUs that had become vested by their terms on Vesting Dates prior to the Corporate Change of Control and that remain outstanding) shall remain outstanding and shall vest, subject to the Participant’s continued employment with the acquiring or surviving entity, on the applicable Vesting Date or, if earlier, upon an Involuntary Employment Action as described in Section 10.C. of the Plan or the Participant’s termination of employment on account of death or Disability;

(iii)to the extent the acquiring or surviving entity does not assume, continue or substitute for any then outstanding Granted MSUs (determined after giving effect to clause (i) above) in connection with the Corporate Change in Control, the Granted MSUs (including any Granted MSUs that had become vested by their terms on Vesting Dates prior to the Corporate Change of Control and that remain outstanding) shall vest in full as of immediately prior to the Corporate Change in Control; and

(iv)notwithstanding clause (iii) or (iv) above, with respect to a Participant who is or becomes eligible for Retirement at any time after the Grant Date and on or before the latest Vesting Date described in Section 2.B. above, to the extent required to avoid adverse tax results under Section 409A, all then outstanding and unvested Granted MSUs (determined after giving effect to clause (i) above) (including any Granted MSUs that had become vested by their terms on Vesting Dates prior to the Corporate Change of Control and that remain outstanding) shall vest in full as of immediately prior to the Corporate Change in Control.

D.Except as otherwise provided in the Plan or Section 2.C. above, upon termination of the Participant’s employment with the Company and its Affiliates for any reason, any portion of the Award that is not then vested will immediately terminate, except as follows:

(i)any portion of the Award held by the Participant immediately prior to the Participant’s termination of employment on account of death or Disability will, to the extent not vested previously, become eligible to vest as of the date of such termination of employment, and such Granted MSUs then eligible to vest will vest in accordance with Section 2.B.(ii) with the date of the termination of employment serving as the applicable Vesting Date; and

(ii)any portion of the Award held by the Participant immediately prior to the Participant’s Retirement, to the extent not vested previously, will remain outstanding and will remain eligible to vest over the remainder of the Vesting Period as set forth in Section 2.B.(i) without regard to the service requirement specified in Section 2.A., with respect to fifty percent (50%) of the number of Granted MSUs covered by such unvested portion and with respect to an additional ten percent (10%) of the number of Granted MSUs covered by such unvested portion for every full year of employment by the Company and its Affiliates beyond ten (10) years, up to the remaining amount of the unvested Granted MSUs, and such Granted MSUs that become eligible to vest will vest in accordance with Section 2.B.(ii). For the avoidance of doubt, Retirement means the Participant’s leaving the employment of the Company and its Affiliates after reaching age 55 with ten (10) consecutive years of service with the Company or its Affiliates, but not including pursuant to any termination For Cause or any termination for insufficient performance, as determined by the Company.

E.Notwithstanding anything herein to the contrary, any portion of the Award held by a Participant or a Participant’s permitted transferee immediately prior to the cessation of the Participant’s employment For Cause shall terminate at the commencement of business on the date of such termination.

A.With respect to a Participant who is not and does not prior to the latest Vesting Date described in Section 2.A. above become eligible for Retirement, within 30 days following the date on which a Granted MSU becomes vested, the Company shall issue to the Participant, subject to applicable withholding as described in Section 7 of this Agreement, one share of common stock of the Company (“Common Stock”) (or, in the case of an assumption or substitution described in Section 2.C.(ii) above, common stock of the acquiring or surviving entity or such other cash or property payable under the assumed or substituted award) in satisfaction of each vested MSU.

B.With respect to a Participant who is or becomes eligible for Retirement at any time during the Vesting Period, to the extent required to avoid adverse tax results under Section 409A and notwithstanding anything to the contrary in this Agreement, the Company shall issue to the Participant, subject to applicable withholding as described in Section 7 of this Agreement, one share of Common Stock (or, in the case of an assumption or substitution described in Section 2.C.(ii) above, common stock of the acquiring or surviving entity or such other cash or property payable under the assumed or substituted award) in satisfaction of each vested MSU (determined in accordance with Section 2 of this Agreement and Section 10 of the Plan) within 30 days of the earliest of (i) the applicable Vesting Date or (ii) the date on which a Corporate Change in Control occurs.

C.If you are a “specified employee” (as defined in Section 409A), you will be paid on the earlier of (i) the date which is six months after you separate from service (within the meaning of Section 409A) or (ii) the date of your death or Disability. The preceding sentence will not apply to any payments that are exempt from or are not subject to the requirements of Section 409A. For the avoidance of doubt, if payments would be made under Section 3.B.(i) or Section 3.B.(ii) before the six month payment date on account of other than your separation from service, such payment will be made under Section 3.B.(i) or Section 3.B.(ii), as applicable.

The Committee may cancel, rescind, withhold or otherwise limit or restrict the Award prior to payment at any time if the Participant is not in compliance with all applicable provisions of this Agreement and the Plan, or if the Participant engages in any Detrimental Activity.

The Participant shall not have any rights as a stockholder with respect to any shares of Common Stock to be issued under the Award until he or she becomes the holder of such shares. Accordingly, the Award shall not be interpreted to bestow upon the Participant any equity interest or ownership in the Company or any Affiliate prior to the date on which the Company delivers to the Participant shares of Common Stock. Furthermore, the Participant is not entitled to vote any Common Stock by reason of the granting of the Award or to receive or be credited with any dividends declared and payable on any share of Common Stock underlying the Award prior to the payment date with respect to such share.

The obligations of the Company and its Affiliates hereunder shall be contractual only and all such payments shall be made from the general assets of the Company or its Affiliates. The Participant shall rely solely on the unsecured promise of the Company and nothing herein shall be construed to give the Participant or any other person or persons any right, title, interest or claim in or to any specific asset, fund, reserve, account or property of any kind whatsoever owned by the Company or any Affiliate.

Awards will be subject to income tax withholding and reporting as required under local law. If statutory withholding of taxes and/or social insurance is required at the time of vesting, the Company will withhold from delivery to the Participant a number of shares of Common Stock equal in value to the statutory minimum amount required to be withheld. A similar amount of cash will be paid by the Company on behalf of the Participant to the applicable tax authorities. The number of shares to be withheld will be calculated using the closing sales price of a share of Common Stock (or, in the case of an assumption or substitution described in Section 2.C.(ii) above, common stock of the acquiring or surviving entity or such other cash or property payable under the assumed or substituted award) on the applicable Vesting Date. Shares (net of the number withheld for the payment of withholding taxes, if applicable) will be delivered to the Participant’s stock plan account upon vesting in accordance with the Plan. The Company may, in its discretion, permit Participants to make alternative arrangements for payment of any such taxes and/or social insurance.

In certain cases, local law may require that an award be subject to tax earlier than the date of payment. If that occurs, the Company will notify the Participant and will deduct the required tax amount from the Participant’s pay in accordance with applicable law.

The Award is subject to the provisions of the Plan, which are incorporated herein by reference, and in the event of any inconsistency or conflict between the provisions of this Agreement and the Plan, the provisions of the Plan shall control. A copy of the Plan as in effect on the Grant Date has been made available electronically to the Participant.

The grant of the Award shall not constitute a contract of employment or confer upon the Participant any right with respect to the continuance of his/her employment by or other service with the Company or any Affiliate, nor shall it or they be construed as affecting the rights of the Company (or any Affiliate) to terminate the service of the Participant at any time or otherwise change the terms of such service, including, without limitation, the right to promote, demote or otherwise re-assign the Participant from one position to another within the Company or any Affiliate.

The provisions of the Award and this Agreement shall be governed by and interpreted in accordance with the laws of the State of Delaware.

IN WITNESS WHEREOF, the Company has caused this instrument to be executed by its duly authorized officer.

By:    Michel Vounatsos    

Chief Executive Officer