As filed with the Securities and Exchange Commission on May 1, 2025

No. 333-   

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

BIOGEN INC.

(Exact name of registrant as specified in its charter)

225 Binney Street, Cambridge, MA 02142

(617) 679-2000

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Susan H. Alexander, Esq.

Executive Vice President and Chief Legal Officer

Biogen Inc.

225 Binney Street

Cambridge, Massachusetts 02142

(617) 679-2000

(Name, address, including zip code, and telephone number, including area code, of agent for service)

With copies to:

John R. Ablan

Willkie Farr & Gallagher LLP

300 North LaSalle Drive

Chicago, Illinois 60654

(312) 728-9000

Approximate Date of Commencement of Proposed Sale to the Public: From time to time after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ☒

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

PROSPECTUS

Biogen Inc.

Common Stock

Preferred Stock

Debt Securities

Warrants

Depositary Shares

Biogen Inc. may offer and sell from time to time, in one or more series or issuances and on terms determined at the time of the offering, any combination of the securities described in this prospectus.

This prospectus describes some of the general terms of these securities. The specific terms of the securities to be offered will be described in supplements to this prospectus, together with other terms and matters related to the offering. The prospectus supplements may also add, update or change information contained or incorporated by reference in this prospectus. This prospectus may be used to offer and sell securities only if accompanied by a prospectus supplement. You should read carefully both this prospectus and the applicable prospectus supplement, along with the additional information described under the heading “Where You Can Find More Information,” before making an investment decision.

We may offer and sell the securities on an immediate, continuous or delayed basis directly to investors or through underwriters, dealers or agents, or through a combination of any of these methods at prices and on terms determined at the time of offering.

Our common stock trades on the Nasdaq Global Select Market under the symbol “BIIB.”

Investing in these securities involves certain risks. Please carefully read the information under the heading “Risk Factors” on page 6 of this prospectus before you invest in our securities. We may include additional risk factors in any prospectus supplement, any related free writing prospectus and/or any other future filings we make with the Securities and Exchange Commission that are incorporated by reference into this prospectus and into the applicable prospectus supplement.

The address of our principal executive offices is 225 Binney Street, Cambridge, Massachusetts 02142, and our telephone number at our principal executive offices is (617) 679-2000.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is May 1, 2025.

Table of Contents

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission (“SEC”) utilizing a shelf registration process. Under this shelf process, we may, from time to time, sell any combination of the common stock, preferred stock, debt securities, warrants or depositary shares described in this prospectus in one or more offerings. You should read this prospectus along with any accompanying prospectus supplement and the documents incorporated herein and therein carefully before you invest. These documents contain important information you should consider when making your investment decision. This prospectus contains information about the securities we may offer generally. Each time we offer or sell securities, we will provide a prospectus supplement and, in some cases, a pricing supplement, that will contain information about the specific securities being offered. The prospectus supplement or pricing supplement may also add, update or change information in this prospectus or in any of the documents that we have incorporated by reference into this prospectus. You should assume that the information provided in this prospectus, any prospectus supplement, any free writing prospectus or any pricing supplement, and the information provided in the documents incorporated by reference herein and therein, are accurate only as of the date of the applicable document. Neither the delivery of this prospectus or any prospectus supplement, nor any offer or sale made hereunder, shall under any circumstances create any implication that there has been no change in our affairs since such date, or that the information contained or incorporated by reference into this prospectus, any prospectus supplement, any free writing prospectus or any pricing supplement is correct as of any time subsequent to the date of such document.

You should not consider any information in this prospectus, any prospectus supplement or any of the documents incorporated by reference herein or therein to be investment, legal or tax advice. You should consult your own counsel, accountants and other advisers for legal, tax, business, financial and related advice regarding the purchase of any securities.

We have not authorized anyone to provide any information other than that contained or incorporated by reference in this prospectus, in any accompanying prospectus supplement, in any free writing prospectus or in any pricing supplement prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you.

To the extent there is a conflict between the information contained in this prospectus, on the one hand, and the information contained in a prospectus supplement, on the other hand, the information contained in the prospectus supplement shall control. If any statement in this prospectus conflicts with any statement in a document that we have incorporated by reference, then you should consider only the statement in the more recent document.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.”

Unless otherwise indicated or unless the context requires otherwise, all references in this prospectus to the “Company,” “Biogen,” “we,” “us” and “our” refer to Biogen Inc. and its consolidated subsidiaries.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website at http://www.sec.gov that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC. Filings that we make with the SEC also can be found on our website at http://www.biogen.com. The information contained on or accessible through our corporate website or any other website that we may maintain is not incorporated by reference herein and is not part of this prospectus or the registration statement of which this prospectus is a part.

The SEC’s rules allow us to “incorporate by reference” the information we have filed with the SEC, which means that we can disclose important information by referring you to those documents. The information incorporated by reference is a part of this prospectus, and information that we file later with the SEC that is incorporated by reference in this prospectus will automatically update and supersede this information. We incorporate by reference into this prospectus the documents listed below and any future filings made by us with the SEC under Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (excluding any information furnished pursuant to Item 2.02 or Item 7.01 on any Current Report on Form 8-K):

You may obtain documents incorporated by reference into this prospectus at no cost by requesting them in writing or telephoning us at the following address:

Biogen Inc.

Attn: Investor Relations

225 Binney Street

Cambridge, Massachusetts 02142

(617) 464-2442

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DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS

Certain statements in or incorporated by reference in this prospectus and any prospectus supplement are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by words such as “anticipates,” “believes,” “cause,” “continue,” “could,” “depend,” “develop,” “estimates,” “expects,” “forecasts,” “goal,” “guidance,” “have,” “impact,” “implement,” “increase,” “intends,” “lead,” “maintain,” “may,” “might,” “plans,” “potential,” “possible,” “projects,” “reduce,” “remain,” “result,” “scheduled,” “seek,” “should,” “targets,” “will,” “would” and other similar words or expressions, or the negative thereof. The absence of such words or expressions does not necessarily mean the statements are not forward-looking. Examples of forward-looking statements include statements relating to our future financial condition and operating results, as well as any other statement that does not directly relate to any historical or current fact.

Forward-looking statements are based on expectations and assumptions that we believe to be reasonable when made, but that may not prove to be accurate. These statements are not guarantees and are subject to numerous assumptions, risks, uncertainties and changes in circumstances that are difficult to predict. Many factors could cause actual results to differ materially and adversely from these forward-looking statements. Information concerning factors that could cause actual results to differ from those in our forward-looking statements is contained under “Risk Factors” in our annual report on Form 10-K for the year ended December 31, 2024, which is incorporated in this prospectus by reference (and in any of our annual reports on Form 10-K and quarterly reports on Form 10-Q for subsequent periods that are so incorporated). Any forward-looking statement speaks only as of the date on which it is made, and we assume no obligation to update or revise any forward-looking statement whether as a result of new information, future events or otherwise, except as required by law.

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NOTE REGARDING TRADEMARKS

ADUHELM^®, AVONEX^®, BYOOVIZ^®, PLEGRIDY^®, QALSODY^®, RITUXAN^®, RITUXAN HYCELA^®, SKYCLARYS^®, SPINRAZA^®, TECFIDERA^®, TYSABRI^® and VUMERITY^® are registered trademarks of Biogen.

BENEPALI^™, FLIXABI^™, FUMADERM^™, IMRALDI^™ and OPUVIZ^™ are trademarks of Biogen.

ACTEMRA^®, COLUMVI^®, ENBREL^®, EYLEA^®, FAMPYRA^™, GAZYVA^®, LEQEMBI^®, HUMIRA^®, LUCENTIS^®, LUNSUMIO^®, OCREVUS^®, REMICADE^®, ZURZUVAE^™ and other trademarks referenced in this prospectus are the property of their respective owners.

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THE COMPANY

Biogen is a global biopharmaceutical company focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases. We have a broad portfolio of medicines to treat multiple sclerosis, have introduced the first approved treatment for spinal muscular atrophy, co-developed treatments to address a defining pathology of Alzheimer’s disease and launched the first approved treatment to target a genetic cause of amyotrophic lateral sclerosis. We market the first and only drug approved in the U.S. and the E.U. for the treatment of Friedreich’s ataxia in adults and adolescents aged 16 years and older. We are focused on advancing our pipeline in neurology, specialized immunology and rare diseases. We support our drug discovery and development efforts through internal research and development programs, external collaborations and acquisitions.

Our marketed products include TECFIDERA, VUMERITY, AVONEX, PLEGRIDY and TYSABRI for the treatment of multiple sclerosis; SPINRAZA for the treatment of spinal muscular atrophy; SKYCLARYS for the treatment of Friedreich’s ataxia; QALSODY for the treatment of amyotrophic lateral sclerosis; and FUMADERM for the treatment of severe plaque psoriasis.

We also have collaborations on the commercialization of LEQEMBI for the treatment of Alzheimer’s disease and on the commercialization of ZURZUVAE for the treatment of postpartum depression. We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin’s lymphoma, chronic lymphocytic leukemia and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin’s lymphoma and chronic lymphocytic leukemia; GAZYVA for the treatment of chronic lymphocytic leukemia and follicular lymphoma; OCREVUS for the treatment of primary progressive multiple sclerosis and relapsing multiple sclerosis; LUNSUMIO for the treatment of relapsed or refractory follicular lymphoma; COLUMVI, a bispecific antibody for the treatment of non-Hodgkin’s lymphoma; and have the option to add other potential anti-CD20 therapies, pursuant to certain collaboration arrangements.

We commercialize a portfolio of biosimilars of advanced biologics including: BENEPALI, an etanercept biosimilar referencing ENBREL; IMRALDI, an adalimumab biosimilar referencing HUMIRA; FLIXABI, an infliximab biosimilar referencing REMICADE; and BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets. We also have commercialization rights related to OPUVIZ, an aflibercept biosimilar referencing EYLEA.

Our principal executive offices are located at 225 Binney Street, Cambridge, Massachusetts 02142, and our telephone number is (617) 679-2000.

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RISK FACTORS

Investing in our securities involves certain risks. For a discussion of the factors you should carefully consider before deciding to purchase any of these securities, see “Part II, Item 1A—Risk Factors” of our Quarterly Report on Form 10-Q for the quarter ended March 31, 2025 and “Part I, Item 1A—Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2024, which are incorporated by reference in this prospectus, and any subsequent filings with the SEC, together with all of the other information included in this prospectus and in the “Risk Factors” section of any applicable prospectus supplement or filing with the SEC and the other information that we have incorporated by reference.

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USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered by us hereby. Unless otherwise provided in any applicable prospectus supplement, pricing supplement or free writing prospectus, we will use the net proceeds from the sale of the securities for repaying debt, making capital investments, funding working capital requirements or other general corporate purposes, including financing acquisitions and refinancing existing indebtedness. Until the net proceeds have been used for their intended purposes, they may be held in cash or cash equivalents or temporarily used or invested.

DESCRIPTION OF CAPITAL STOCK

Set forth below is a summary of the material terms of our capital stock. This summary is not complete. It is subject to and qualified in its entirety by reference to our Amended and Restated Certificate of Incorporation, as amended (the “Certificate of Incorporation”), and our Fifth Amended and Restated Bylaws, as amended (the “Bylaws”), each of which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part. We encourage you to read our Certificate of Incorporation, our Bylaws and the applicable provisions of the General Corporation Law of the State of Delaware, as the same exists or may be hereafter amended (the “DGCL”), for additional information.

Authorized Capital Stock

Our authorized capital stock consists of 1,000,000,000 shares of common stock, par value $0.0005 per share (“Common Stock”), and 8,000,000 shares of preferred stock, par value $0.001 per share (“Preferred Stock”).

Common Stock

Voting Rights

Holders of Common Stock are entitled to one vote per share on all matters voted on by the stockholders, including the election of directors. Our Common Stock does not have cumulative voting rights.

Dividend Rights

Subject to the rights of holders of all classes of stock at the time outstanding having prior rights as to dividends, if any, the holders of Common Stock are entitled to receive dividends, if any, as may be declared from time to time by the Board of Directors in its discretion out of funds legally available for the payment of dividends.

Liquidation Rights

Subject to any preferential rights of outstanding shares of Preferred Stock, if any, holders of Common Stock will share ratably in all assets legally available for distribution to our stockholders in the event of liquidation, dissolution or winding up of the Company.

Other Rights and Preferences

Our Common Stock has no sinking fund or redemption provisions or preemptive, conversion or exchange rights. Holders of our Common Stock may act by unanimous written consent.

Transfer Agent and Registrar

The transfer agent and registrar for our Common Stock is Computershare Trust Company, N.A.

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Listing

The Common Stock is traded on The Nasdaq Stock Market LLC under the trading symbol “BIIB.”

Preferred Stock

Our Board of Directors may, without further action by the stockholders, issue Preferred Stock in one or more series and fix the rights and preferences thereof. Our Certificate of Incorporation grants the Board of Directors authority to issue Preferred Stock and to determine its rights and preferences without the need for further stockholder approval.

Examples of rights and preferences the Board of Directors may fix include dividend rates, conversion rights, voting rights, preemptive rights, terms of redemption (including sinking fund provisions), redemption prices, and liquidation preferences. The issuance of Preferred Stock, while providing desirable flexibility in connection with possible financings, could have the effect of making it more difficult for a third party to acquire, or of discouraging a third party from acquiring, a majority of our outstanding voting stock.

The terms of any particular series of Preferred Stock will be described in the prospectus supplement relating to the offering of shares of that particular series of Preferred Stock and may include, among other things:

Anti-Takeover Effects of our Certificate of Incorporation and Bylaws and Delaware Law

Certain provisions of our Certificate of Incorporation and Bylaws may be deemed to have an anti-takeover effect and may prevent, delay, or defer a tender offer or takeover attempt that a stockholder may deem to be in his, her, or its best interest. The existence of these provisions also could limit the price that investors might be willing to pay for our securities.

Authorized but Unissued Shares

The authorized but unissued shares of our Common Stock and Preferred Stock are available for future issuance without stockholder approval, subject to any limitations imposed by The Nasdaq Stock Market LLC.

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These additional shares may be utilized for a variety of corporate purposes. In particular, our Board of Directors could issue shares of Preferred Stock that could, depending on the terms of the series, impede the completion of a takeover effort. Our Board of Directors may determine that the issuance of such shares of Preferred Stock is in the best interest of the Company and our stockholders. Such issuance could discourage a potential acquiror from making an unsolicited acquisition attempt through which such acquiror may be able to change the composition of the Board of Directors, including a tender offer or other transaction a majority of our stockholders might believe to be in their best interest or in which stockholders might receive a substantial premium for their stock over the then-current market price.

Advance Notice Requirements for Stockholder Proposals and Director Nominations

Our Bylaws provide advance notice procedures for stockholders seeking to bring business before our annual meeting of stockholders or to nominate candidates for election as directors at any meeting of stockholders. Our Bylaws also specify certain requirements regarding the form and content of a stockholder’s notice. These provisions may preclude our stockholders from bringing matters before our annual meeting of stockholders or from making nominations for directors at our meetings of stockholders.

Proxy Access

Our Bylaws provide that qualified stockholders can nominate candidates for election to the Board of Directors if such stockholders comply with the requirements contained in our Bylaws within the designated time periods. Under the proxy access provisions of our Bylaws, any stockholder (or group of up to 20 stockholders) owning 3% or more of our Common Stock for at least three years may nominate a number of candidates for election to our Board of Directors up to 25% of the number of directors in office as of a date specified in the Bylaws or, if such amount is not a whole number, the closest whole number below 25%, but not less than one, and require us to include such nominees in our annual meeting proxy statement if the stockholders and nominees satisfy the requirements contained in our Bylaws.

Stockholder Meetings

Our Bylaws require that special meetings of stockholders be called only by our chair of the Board of Directors, by our chief executive officer, by a resolution duly adopted by the affirmative vote of a majority of the Board of Directors, or by a stockholder or group of stockholders who have Net Long Beneficial Ownership (as defined in our Bylaws) of 25% or more of the outstanding shares of Common Stock as of the date of submission of the request and who satisfy the requirements contained in our Bylaws. Further, business transacted at any special meeting of stockholders called by the requisite number of stockholders is limited to matters relating to the purpose or purposes stated in the notice of meeting, except that the Company may submit additional matters. This limit on the ability of our stockholders to call a special meeting may lengthen the amount of time required to take stockholder proposed actions.

Section 203 of the DGCL

We are subject to Section 203 of the DGCL. This statute regulating corporate takeovers prohibits a Delaware corporation from engaging in any business combination with an interested stockholder for three years following the date that the stockholder became an interested stockholder, unless:

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Generally, a business combination includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. An interested stockholder is any person who, together with such person’s affiliates and associates, (1) owns 15% or more of a corporation’s voting securities or (2) is an affiliate or associate of a corporation and was the owner of 15% or more of the corporation’s voting securities at any time within the three-year period immediately preceding a business combination governed by Section 203. We expect the existence of this provision to have an anti-takeover effect with respect to transactions our Board of Directors does not approve.

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DESCRIPTION OF DEBT SECURITIES

General

We will issue debt securities under an indenture between us and U.S. Bank Trust Company, National Association (as successor in interest to U.S. Bank Trust Company, National Association), as trustee, dated as of September 15, 2015, as amended. To the extent provided in any applicable prospectus supplement, the debt securities may be convertible into, or exchangeable for, shares of any class or classes of our stock, or our other securities or property.

We have summarized material provisions of the indenture and the debt securities below. This summary does not describe all exceptions and qualifications contained in the indenture or the debt securities.

The indenture does not limit the amount of debt securities that may be issued, and each series of debt securities may differ as to its terms.

A supplement to the indenture, board resolution or officers’ certificate will designate the specific terms relating to any new series of debt securities. These terms will be described in a prospectus supplement and, in some cases, a pricing supplement, and will include the following:

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Book-Entry Only Form

The debt securities normally will be issued in book-entry only form, which means that they will be represented by one or more permanent global securities registered in the name of The Depository Trust Company, New York, New York (“DTC”), or its nominee. We will refer to this form as “book-entry only.”

In the event that debt securities are issued in book-entry only form, DTC will keep a computerized record of its participants (for example, your broker) whose clients have purchased the securities. Each participant will then keep a record of its clients who purchased the securities. A global security may not be transferred, except that DTC, its nominees and their successors may transfer an entire global security to one another.

In the case of book-entry only debt securities, we will wire principal and interest payments to DTC’s nominee. We and the trustee will treat DTC’s nominee as the owner of the global securities for all purposes. Accordingly, neither we nor the trustee will have any direct responsibility or liability to pay amounts due on the debt securities to owners of beneficial interests in the global securities.

Under book-entry only form, we will not issue physical certificates representing beneficial interests in the global securities to individual holders of the debt securities. Beneficial interests in global securities will be shown on, and transfers of global securities will be made only through, records maintained by DTC and its participants. Debt securities represented by a global security will be exchangeable for debt securities in certificated form with the same terms in authorized denominations only if:

Certificated Form

Alternatively, we may issue the debt securities in certificated form registered in the name of the debt security holder. Under these circumstances, holders may receive physical certificates representing the debt securities. We refer to this form as “certificated.”

Redemption Provisions

The prospectus supplement relating to a series of debt securities will describe the circumstances, if any, under which we may redeem such series of debt securities. If a series of debt securities is subject to a sinking fund, the prospectus supplement will describe those terms.

Merger, Consolidation or Sale of Assets

Unless otherwise specified in any prospectus supplement with respect to a series of debt securities, the indenture provides that we may not merge or consolidate with or into, or sell, assign, transfer or lease or otherwise dispose of all or substantially all of our properties and assets, to any person, unless at the time of and after giving effect thereto:

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Events of Default

Unless otherwise specified in any prospectus supplement with respect to a series of debt securities, the term “event of default” means, for any series of debt securities, any of the following:

If an event of default (other than due to certain events of bankruptcy, insolvency or reorganization) has occurred and has not been cured, the trustee or the holders of at least 25% in aggregate principal amount of a series of debt securities may, by a notice in writing to us (and to the trustee if given by the holders), declare the entire principal amount (and premium, if any) of, and all the accrued and unpaid interest on, such series to be due and immediately payable. This is called a declaration of acceleration of maturity. If an event of default occurs because of certain events of bankruptcy, insolvency or reorganization relating to us, the principal amount (and premium, if any) of, and all the accrued and unpaid interest on, all debt securities will be automatically accelerated, without any action by the trustee or any holder. Holders of not less than a majority in aggregate principal amount of a series of debt securities may also waive certain past defaults under the indenture on behalf of all of the holders of such series. A declaration of acceleration of maturity with respect to a series of debt securities may be canceled, under specific circumstances, by the holders of at least a majority in aggregate principal amount of such series.

If any debt securities are outstanding under the indenture, the indenture requires us, within 120 days after the end of each fiscal year, to furnish to the trustee a statement as to our compliance with the indenture. The trustee will generally give the holders of a series of debt securities notice within 90 days of the occurrence of a default or an event of default with respect to such series known to the trustee.

Except in cases of default, where the trustee has some special duties, the trustee is not required to take any action under the indenture at the request of any of the holders unless such holders offer the trustee indemnity and/or security satisfactory to it. If indemnity and/or security satisfactory to the trustee is provided, the holders of a majority in aggregate principal amount of a series of debt securities may direct the time, method and place of conducting any lawsuit or other formal legal action seeking any remedy available to the trustee with respect to such series. The trustee may refuse to follow those directions in certain circumstances. No delay or omission in exercising any right or remedy will be treated as a waiver of the right, remedy or event of default.

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Before holders will be allowed to bypass the trustee and bring a lawsuit or other formal legal action or take other steps to enforce their rights or protect their interests relating to a series of debt securities, the following must occur:

However, holders are entitled at any time to bring a lawsuit for the payment of money due on a series of debt securities on or after the due date.

Defeasance

The following provisions will apply to each series of debt securities unless otherwise specified in a prospectus supplement.

Full Defeasance. We can legally release ourselves from any payment or other obligations on a series of debt securities, called “full defeasance,” if, among other requirements, we put in place the following other arrangements for holders of such series to be repaid:

If we accomplish full defeasance with respect to a series of debt securities, as described above, holders of such series would have to rely solely on the trust deposit for repayment on such debt securities. Holders of such debt securities could not look to us for repayment in the unlikely event of any shortfall.

Covenant Defeasance. We can be released from the restrictive covenants in a series of debt securities if, among other requirements, we make the arrangements described below. This is called “covenant defeasance.” In that event, holders of the applicable series of debt securities would lose the protection of those restrictive covenants but would gain the protection of having money and securities set aside in trust to repay such debt securities. In order to achieve covenant defeasance with respect to a series of debt securities, we must, among other requirements, do the following:

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If we accomplish covenant defeasance with respect to a series of debt securities, you can still look to us for repayment of such series if there were a shortfall in the trust deposit.

In order to exercise either full defeasance or covenant defeasance, we must comply with certain other conditions, and no event or condition can exist that would prevent us from making payments of principal, premium and interest, if any, on the applicable series of debt securities on the date the irrevocable deposit is made or at any time during the period ending on the 91st day after the deposit date.

Modification or Waiver

The following provisions will apply to each series of debt securities unless otherwise specified in a prospectus supplement.

We generally may modify and amend the indenture with respect to a series of debt securities with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of such series. However, with respect to a series of debt securities, we may not make any modification or amendment without the consent of each holder of such series if such action would:

Except for certain specified provisions, the holders of at least a majority in aggregate principal amount of the outstanding debt securities of a series may, on behalf of the holders of all debt securities of such series, waive our compliance with certain provisions of the indenture with respect to such series. The holders of not less than a majority in aggregate principal amount of the outstanding debt securities of a series may, on behalf of the holders of all debt securities of such series, waive any past default under the indenture and its consequences with respect to such series, except a default in the payment of the principal of or premium or interest on such series or in respect of a covenant or provision applicable to such series which cannot be modified or amended without the

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consent of the holders of all outstanding debt securities of such series; provided, however, that the holders of a majority in aggregate principal amount of the outstanding debt securities of a series may rescind an acceleration and its consequences, including any payment default that resulted solely from such acceleration with respect to such series.

Notwithstanding the foregoing, without the consent of any holder of debt securities, we may amend or supplement the indenture or the debt securities to, among other reasons:

Satisfaction and Discharge

The following provisions will apply to each series of debt securities unless otherwise specified in a prospectus supplement.

The indenture will cease to be of further effect, and we will be deemed to have satisfied and discharged the indenture with respect to a series of debt securities, when the following conditions have been satisfied:

We will remain obligated to provide for registration of transfer and exchange and to provide notices of redemption.

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SEC Reports

We will file with the trustee, within 15 days after we are required to file the same with the SEC, copies of the quarterly and annual reports and of the information, documents and other reports (or copies of such portions of any of the foregoing as the SEC may prescribe) that we may be required to file with the SEC pursuant to Section 13 or Section 15(d) of the Exchange Act; provided that availability of such reports on a website maintained by the SEC shall be deemed to fulfill this requirement. If we are not required to file information, documents or reports pursuant to either of those sections, then we will file with the trustee and the SEC such reports as may be prescribed by the SEC at such time.

The Trustee

The trustee will be U.S. Bank Trust Company, National Association. U.S. Bank Trust Company, National Association also will be the initial paying agent and registrar.

The indenture provides that, except during the continuance of an event of default under the indenture, the trustee under the indenture will perform only such duties as are specifically set forth in the indenture. Under the indenture, the holders of a majority in aggregate principal amount of the debt securities of a series then outstanding will have the right to direct the time, method and place of conducting any proceeding or exercising any remedy available to the trustee under the indenture with respect to such series, subject to certain exceptions. If an event of default has occurred and is continuing, the trustee under the indenture will exercise such rights and powers vested in it under the indenture and is obligated to use the same degree of care and skill in its exercise as a prudent person would exercise under the same circumstances in the conduct of such person’s own affairs.

The indenture and provisions of the Trust Indenture Act incorporated by reference in the indenture contain limitations on the rights of the trustee under such indenture, should it become a creditor of our company, to obtain payment of claims in certain cases or to realize on certain property received by it in respect of any such claims, as security or otherwise. The trustee under the indenture is permitted to engage in other transactions. However, if the trustee under the indenture acquires any prohibited conflicting interest, it must eliminate the conflict or resign.

The trustee may resign or be removed and a successor trustee may be appointed.

Governing Law

The indenture is, and the debt securities will be, governed by, and construed in accordance with, the laws of the State of New York.

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DESCRIPTION OF WARRANTS

This description only summarizes the terms of warrants that we may offer under this prospectus, any prospectus supplement and related warrant agreements and certificates. You should refer to the applicable prospectus supplement, warrant agreement, including the form of warrant certificate representing the warrants, relating to the specific warrants being offered for complete terms, which would be provided at the time of such offering. Such warrant agreement, together with the warrant certificate, would be filed with the SEC in connection with the offering of the specific warrants.

We may issue warrants for the purchase of Common Stock, Preferred Stock or debt securities. Warrants may be issued independently or together with Common Stock, Preferred Stock or debt securities, and may be attached to or separate from any offered securities.

We may evidence a series of warrants by warrant certificates that we issue under a separate warrant agreement. We may enter into a warrant agreement with a warrant agent and, if so, we will indicate the name and address of the warrant agent in the applicable prospectus supplement relating to the particular series of warrants.

The particular terms of any series of warrants will be described in the prospectus supplement relating to such series. Those terms may include:

Each warrant will entitle its holder to purchase the number of shares of Common Stock, Preferred Stock debt securities or units at the exercise price set forth in, or calculable as set forth in, the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the expiration date set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void. We will specify the

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place or places where, and the manner in which, warrants may be exercised in the applicable prospectus supplement. We will set forth on the reverse side of the applicable certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver upon exercise.

Prior to the exercise of any warrants, holders of the warrants will not have any of the rights of holders of the securities purchasable upon exercise, including any right to vote or to receive any payments of dividends, if applicable.

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DESCRIPTION OF DEPOSITARY SHARES

We may offer (either separately or together with other offered securities) depositary shares representing interests in shares of our preferred stock of one or more series. The depositary shares will be issued under deposit agreements (each, a “deposit agreement”) to be entered into between us and a bank or trust company, as depositary (the “preferred stock depositary”), identified in the prospectus supplement or free writing prospectus.

Because this section is a summary, it does not describe every aspect of the depositary shares and deposit agreement. We urge you to read the deposit agreement because it, and not this description, defines your rights as a holder of depositary shares. The form of deposit agreement, including the form of depositary receipts evidencing depositary shares (the “depositary receipts”), is incorporated by reference as an exhibit to this registration statement. See “Where You Can Find More Information” for information on how to obtain a copy of the deposit agreement.

The following is a general description of the terms and provisions of the depositary shares to which any prospectus supplement or term sheet may relate. The specific terms of any depositary shares proposed to be sold under this prospectus will be described in the prospectus supplement or term sheet. If so indicated in the prospectus supplement or term sheet, the terms of the depositary shares may differ from the terms set forth below.

General

We may provide for the issuance by the preferred stock depositary to the public of the depositary receipts evidencing the depositary shares, each of which will represent a fractional interest (to be specified in the prospectus supplement or term sheet) in one share of the related preferred stock, as described below.

You should read the prospectus supplement or term sheet for the material terms of the depositary shares offered thereby, including the following:

If applicable, the prospectus supplement or term sheet will also contain a discussion of the United States federal income tax considerations relevant to the offering.

Depositary receipts will be exchangeable for new depositary receipts of different denominations. We will not impose a service charge for any permitted transfer or exchange of depositary receipts, but we may require payment of any tax or other governmental charge payable in connection therewith. Subject to the terms of the deposit agreement, each owner of a depositary share will be entitled, in proportion to the applicable fractional interest in a share of preferred stock of the series represented by the depositary share, to all rights and preferences of the preferred stock represented by the depositary share, including dividend, voting and liquidation rights and any redemption, conversion or exchange rights.

Dividends and Other Distributions

The preferred stock depositary will distribute all cash dividends and other cash distributions received in respect of the related series of preferred stock to the record holders of the depositary shares in proportion to the

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number of the depositary shares owned by the holders on the relevant record date. The preferred stock depositary will distribute only the amount, however, as can be distributed without attributing to any holder of depositary shares a fraction of one cent, and any balance not so distributed will be added to and treated as part of the next sum, if any, received by the preferred stock depositary for distribution to record holders of depositary shares.

In the event of a distribution other than in cash, the preferred stock depositary will distribute property received by it to the record holders of depositary shares entitled thereto, unless the preferred stock depositary determines that it is not feasible to make the distribution, in which case the preferred stock depositary may, with our approval, sell the property and distribute the net proceeds from the sale to the holders.

The deposit agreement will also contain provisions relating to the manner in which any subscription or similar rights offered by us to holders of the related series of preferred stock will be made available to holders of depositary shares.

Withdrawal of Preferred Stock

Upon surrender of depositary receipts at the corporate trust office of the preferred stock depositary (unless the related shares of preferred stock have previously been called for redemption), the holder of the depositary shares evidenced thereby will be entitled to receive at that office, to or upon the holder’s order, the number of whole shares of the related series of preferred stock and any money or other property represented by the depositary shares. Shares of preferred stock so withdrawn, however, may not be redeposited. If the holder requests withdrawal of less than all the shares of preferred stock to which the holder is entitled, or if the holder would otherwise be entitled to a fractional share of preferred stock, the preferred stock depositary will deliver to the holder a new depositary receipt evidencing the balance or fractional share.

Redemption of Depositary Shares

Whenever we redeem preferred stock held by the preferred stock depositary, the preferred stock depositary will redeem as of the same redemption date the number of depositary shares representing the preferred stock so redeemed; provided that we have paid in full to the preferred stock depositary the redemption price of the preferred stock plus an amount equal to any accrued and unpaid dividends thereon to the date fixed for redemption. The redemption price per depositary share will be equal to the applicable fraction of the redemption price per share and accrued and unpaid dividends payable with respect to the preferred stock. If less than all the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by lot or pro rata or by another equitable method, in each case as may be determined by us.

After the date fixed for redemption, the depositary shares so called for redemption will no longer be deemed to be outstanding and all rights of the holders of the depositary shares will cease, except the right to receive the moneys payable upon the redemption and any money or other property to which the holders of the depositary shares were entitled upon the redemption and surrender to the preferred stock depositary of the depositary receipts evidencing the depositary shares.

Conversion and Exchange

Depositary shares are not convertible into or exchangeable for other shares of our stock or other securities. Nevertheless, if the preferred stock represented by depositary shares is convertible into or exchangeable for other shares of our stock or other securities, the depositary receipts evidencing the depositary shares may be surrendered by the holder thereof to the preferred stock depositary with written instructions to convert or exchange the preferred stock into whole shares of our other stock or other securities, as specified in the related prospectus supplement or term sheet. Upon receipt of these instructions and any amounts payable in respect thereof, we will cause the conversion or exchange thereof and will deliver to the holder whole shares of our other stock or the whole number of other securities (and cash in lieu of any fractional share or security). In the case of a partial conversion or exchange, the holder will receive a new depositary receipt evidencing the unconverted or unexchanged balance.

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Voting the Preferred Stock

Upon receipt of notice of any meeting at which holders of one or more series of preferred stock are entitled to vote, the preferred stock depositary will mail the information contained in the notice of meeting to the holders of the depositary shares relating to the preferred stock. Each record holder of the depositary shares on the record date for the meeting will be entitled to instruct the preferred stock depositary as to the manner in which to vote the number of shares of preferred stock represented by the depositary shares. We will agree to take all reasonable action that may be deemed necessary by the preferred stock depositary in order to enable the preferred stock depositary to vote in accordance with each holder’s instructions. The preferred stock depositary will abstain from voting preferred stock to the extent it does not receive instructions from the holders of depositary shares representing the preferred stock.

Amendment and Termination of the Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between the preferred stock depositary and us. However, any amendment that materially and adversely alters the rights of the holders of depositary shares will not be effective unless the amendment has been approved by the holders of at least a majority of the depositary shares then outstanding (or any greater amount as may be required by the rules of any exchange on which the depositary shares are listed); provided that any amendment that prejudices any substantial right of the holders of depositary shares will not become effective until the expiration of 90 days after notice of the amendment has been given to the holders. A holder that continues to hold one or more depositary receipts at the expiration of the 90-day period will be deemed to consent to, and will be bound by, the amendment. No amendment may impair the right of any holder to surrender the holder’s depositary receipt and receive the related preferred stock, as discussed above under “Withdrawal of Preferred Stock.”

We may terminate the deposit agreement at any time upon not less than 60 days’ prior written notice to the preferred stock depositary. In that case, the preferred stock depositary will deliver to each holder of depositary shares, upon surrender of the related depositary receipts, the number of whole shares of the related series of preferred stock to which the holder is entitled, together with cash in lieu of any fractional share.

The deposit agreement will terminate automatically after all the related preferred stock has been redeemed, withdrawn, converted or exchanged or there has been a final distribution in respect of the preferred stock represented by the depositary shares in connection with our liquidation, dissolution or winding up.

Charges of Preferred Stock Depositary

Except as provided in the prospectus supplement or term sheet, we will pay the fees and expenses of the preferred stock depositary, and the holders of depositary receipts will be required to pay any tax or other governmental charge that may be imposed in connection with the transfer, exercise, surrender or split-up of depositary receipts.

Miscellaneous

The preferred stock depositary will forward to the holders of depositary shares all reports and communications from us that are delivered to the preferred stock depositary and that we are required to furnish to the holders of the preferred stock. Neither the preferred stock depositary nor we will be liable if prevented or delayed by law or any circumstance beyond the preferred stock depositary’s or our control in performing the preferred stock depositary’s or our respective obligations under the deposit agreement. The obligations of the preferred stock depositary and us under the deposit agreement will be limited to performance in good faith and without gross negligence of the preferred stock depositary’s or our respective duties thereunder, and neither the preferred stock depositary nor we will be obligated to prosecute or defend any legal proceeding in respect of any depositary shares or related shares of preferred stock unless satisfactory indemnity is furnished.

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Resignation and Removal of Preferred Stock Depositary

The preferred stock depositary may resign at any time by delivering to us notice of its election to do so, and we may at any time remove the preferred stock depositary, the resignation or removal to take effect upon the appointment of a successor preferred stock depositary. The successor preferred stock depositary must be appointed within 60 days after delivery of a notice of resignation or removal and must be a bank or trust company having its principal office in the United States.

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PLAN OF DISTRIBUTION

General

The securities may be sold:

The prospectus supplement for each series of securities we sell will describe, to the extent required, information with respect to that offering, including:

Underwriters

If underwriters are used in the sale, we will execute an underwriting agreement with those underwriters relating to the securities that we will offer. Unless otherwise set forth in the applicable prospectus supplement, the obligations of the underwriters to purchase these securities will be subject to conditions and the underwriters will be obligated to purchase all of these securities if any are purchased.

The securities subject to an underwriting agreement will be acquired by the underwriters for their own account and may be resold by them from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may be deemed to have received compensation from us in the form of underwriting discounts or commissions and

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may also receive commissions from the purchasers of these securities for whom they may act as agent. Underwriters may sell these securities to or through dealers. These dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agent. Any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

Agents and Dealers

We may also sell any of the securities through agents designated by us from time to time. We will name any agent involved in the offer or sale of these securities and will list commissions payable by us to these agents in the applicable prospectus supplement. These agents will be acting on a best efforts basis to solicit purchases for the period of their appointment, unless we state otherwise in the applicable prospectus supplement.

We may also sell securities to dealers acting as principals. If we sell our securities to a dealer as a principal, then the dealer may resell those securities to the public at varying prices to be determined by such dealer at the time of resale.

Direct Sales

We may sell any of the securities directly to purchasers. In this case, we will not engage underwriters, agents or dealers in the offer and sale of the applicable securities.

Institutional Purchasers

Further, we may authorize underwriters, agents or dealers to solicit offers by certain types of purchasers to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future.

Indemnification

We may indemnify underwriters, dealers or agents who participate in the distribution of securities against certain liabilities, including liabilities under the Securities Act of 1933, as amended, and agree to contribute to payments which these underwriters, dealers or agents may be required to make.

No Assurance of Liquidity

The securities registered hereby may be a new issue of securities with no established trading market. Any underwriters that purchase such securities from us may make a market in these securities. The underwriters will not be obligated, however, to make a market and may discontinue market-making at any time without notice to holders of such securities. We cannot assure you that there will be liquidity in the trading market for any such securities.

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LEGAL MATTERS

Unless the applicable prospectus supplement indicates otherwise, the validity of the securities offered by this prospectus and any prospectus supplement will be passed upon for us by Willkie Farr & Gallagher LLP, Chicago, Illinois.

EXPERTS

The financial statements and management’s assessment of the effectiveness of our internal control over financial reporting (which is included in Management’s Annual Report on Internal Control over Financial Reporting) incorporated in this prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2024, have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

The following table sets forth all fees and expenses payable by the registrant in connection with the issuance and distribution of the securities being registered hereby (other than underwriting discounts and commissions). All amounts are estimated.

Article X of the registrant’s Amended and Restated Certificate of Incorporation, as amended, provides for the elimination of personal monetary liabilities of directors and officers of Biogen for any breach of their fiduciary duties to the full extent permitted by the General Corporation Law of Delaware (the “DGCL”). Section 102(b)(7) of the DGCL enables a corporation in its certificate of incorporation to eliminate or limit the personal liability of members of its Board of Directors or officers to the corporation or its shareholders for monetary damages for breach of fiduciary duty as a director or officer, provided that the corporation shall not eliminate or limit the liability of: (i) a director or officer breaching his or her duty of loyalty to the corporation or its stockholders; (ii) a director or officer failing to act in good faith, engaging in intentional misconduct or knowingly violating the law; (iii) a director paying an unlawful dividend or approving an unlawful stock purchase or redemption; (iv) a director or officer obtaining an improper personal benefit; or (v) an officer in any action by or in the right of the corporation.

Section 145 of the DGCL provides that a corporation may indemnify directors and officers as well as other employees and agents against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with specified actions, suits or proceedings, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation - a “derivative action”), if they acted in good faith and in a manner they reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal action or proceeding, had no reasonable cause to believe their conduct was unlawful. A similar standard is applicable in the case of derivative actions, except that indemnification only extends to expenses (including attorneys’ fees) actually and reasonably incurred in connection with the defense or settlement of such action, and the statute requires court approval before there can be any indemnification where the person seeking indemnification has been found liable to the corporation. Indemnification provided pursuant to Section 145 of the DGCL is not exclusive of any other rights to which those seeking indemnification may be entitled to under any bylaw, agreement, disinterested director vote, stockholder vote or otherwise.

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The registrant’s Fifth Amended and Restated Bylaws provide that the registrant shall provide, to the fullest extent authorized by the DGCL, indemnification against all expense, liability and loss (including attorneys’ fees, judgments, fines, ERISA excise taxes or penalties, and amounts paid or to be paid in settlement) reasonably incurred or suffered by its directors, officers, or any other person who is or was serving at the request of the registrant (or any predecessor) as a director, officer, employee, fiduciary, representative, partner or agent of another related entity and shall advance expenses to such persons, in respect of any action, suit or proceeding, whether civil, criminal, administrative or investigative, by reason of the fact that he or she is or was serving in such capacity.

In addition, the registrant maintains directors’ and officers’ liability insurance which insures against certain liabilities that directors or officers of the registrant may incur in such capacities.

The registrant also has in place agreements with certain of its officers and directors which affirm the registrant’s obligation to indemnify them to the fullest extent permitted by law and contain various procedural and other provisions which expand the protection afforded by the registrant’s Bylaws.

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The undersigned registrant hereby undertakes:

1. To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (1)(i), (1)(ii) and (1)(iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

2. That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

3. To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

4. That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

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(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

5. That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

6. That, for the purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

7. Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

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SIGNATURES AND POWER OF ATTORNEY

Pursuant to the requirements of the Securities Act, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on May 1, 2025.

Pursuant to the requirements of the Securities Act, this registration statement has been signed by the following persons in the capacities indicated on May 1, 2025.

Further, we, the undersigned officers and directors of the registrant hereby severally constitute and appoint Christopher A. Viehbacher, Robin C. Kramer, and Susan H. Alexander and each of them singly, our true and lawful attorneys with full power to them, and each of them singly, to sign for us and in our names in the capacities as indicated, any and all amendments or supplements to this registration statement on Form S-3 of the registrant, including post-effective amendments to the Registration Statement, and generally to do all such things in connection therewith in our name and on our behalf in our capacities as indicated to enable the registrant to comply with the provisions of the Securities Act and all requirements of the SEC, hereby ratifying and confirming our signatures as they may be signed by our said attorneys or any of them, to any and all amendments.

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II-6

Exhibit 5.1

				300 North LaSalle Chicago, IL 60654-3406 Tel: 312 728 9000 Fax: 312 728 9199

May 1, 2025

Biogen Inc.

225 Binney Street

Cambridge, Massachusetts 02142

Ladies and Gentlemen:

We have acted as special counsel Biogen Inc., a Delaware corporation (the “Company”), in connection with the filing with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), of a Registration Statement on Form S-3 (the “Registration Statement”) relating to the proposed issuance from time to time of (i) shares of common stock of the Company, par value $0.0005 per share (the “Common Stock”), (ii) shares of preferred stock of the Company, par value $0.001 per share (the “Preferred Stock”), (iii) debt securities, (the “Debt Securities”), pursuant to an indenture (the “Indenture”), dated as of September 15, 2015, between the Company and U.S. Bank Trust Company, National Association (as successor in interest to U.S. Bank National Association), as trustee (the “Trustee”), (iv) warrants (the “Warrants”) representing rights to purchase Common Stock, Preferred Stock or Debt Securities pursuant to a Warrant Agreement (the “Warrant Agreement”) and (v) depositary shares representing fractional interests in Preferred Stock (the “Depositary Shares” and, together with the Common Stock, the Preferred Stock, the Debt Securities and the Warrants, the “Securities”) pursuant to a deposit agreement (the “Deposit Agreement”).

In rendering the opinions expressed below, we have (a) examined and relied on the originals, or copies certified or otherwise identified to our satisfaction, of such agreements, documents and records of the Company and such other instruments and certificates of public officials and officers and representatives of the Company as we have deemed necessary or appropriate for the purposes of such opinions, (b) examined and relied as to factual matters upon, and have assumed the accuracy of, the statements made in the certificates of public officials and officers and representatives of the Company delivered to us and (c) made such investigations of law as we have deemed necessary or appropriate as a basis for such opinions. In rendering the opinions expressed below, we have assumed, with your permission, without independent investigation or inquiry, (i) the authenticity and completeness of all documents submitted to us as originals, (ii) the genuineness of all signatures on all documents that we examined, (iii) the conformity to authentic originals and completeness of documents submitted to us as certified,

BRUSSELS CHICAGO DALLAS FRANKFURT HOUSTON LONDON  LOS ANGELES MILAN

MUNICH NEW YORK PALO ALTO PARIS ROME SAN FRANCISCO WASHINGTON

Biogen Inc.

May 1, 2025

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conformed or reproduction copies, (iv) the legal capacity of all natural persons executing documents, (v) the power and authority of the Trustee to enter into and perform its obligations under the Indenture, (vi) the due authorization, execution and delivery of the Indenture by the Trustee, (vii) the enforceability of the Indenture against the Trustee, (viii) the Registration Statement and any amendments thereto will be effective under the Securities Act and comply with all applicable laws and such effectiveness will not have been terminated or rescinded, (ix) the appropriate prospectus supplement, free writing prospectus or term sheet relating to the Securities offered thereby will be prepared and filed with the Commission in compliance with the Securities Act and will comply with applicable laws at the time the Securities are offered or issued, (x) such Security will be issued and sold in compliance with the applicable provisions of the Securities Act and in compliance with the “blue sky” laws of certain states and in the manner stated in the Registration Statement and any amendments and supplements thereto, (xi) there will not have occurred any change in law affecting the validity or enforceability of such Security, (xii) at the time of an issuance of shares of Common Stock, including upon conversion, exercise or exchange of any of the Securities that provides for such conversion, exercise or exchange, as the case may be, there will be sufficient shares of Common Stock authorized under the Company’s Amended and Restated Certificate of Incorporation, as restated and/or amended, and not otherwise issued or reserved for issuance, (xiii) at the time of an issuance of shares of Preferred Stock, including upon conversion, exercise or exchange of any of the Securities that provides for such conversion, exercise or exchange, as the case may be, there will be sufficient shares of Preferred Stock authorized under the Company’s Amended and Restated Certificate of Incorporation, as restated and/or amended, and not otherwise issued or reserved for issuance and (xiv) the Company will have timely filed all necessary reports pursuant to the Securities Exchange Act of 1934, as amended, which are incorporated into the Registration Statement by reference.

Based upon and subject to the foregoing and the assumptions, qualifications and limitations hereinafter set forth, we are of the opinion that:

1. When (i) the terms of the issuance and sale of the Common Stock have been duly authorized and approved by all necessary action of the Company’s board of directors (the “Board of Directors”) so as not to violate any applicable law, rule or regulation or result in a default under or a breach of any agreement or instrument binding upon the Company and so as to comply with any requirement or restriction imposed by any court or governmental body having jurisdiction over the Company and (ii) the Common Stock has been duly issued, and delivered as contemplated by the Registration Statement and any prospectus supplement relating thereto, and in accordance with such action of the Board of Directors and the terms of any underwriting agreement, Warrants or Warrant Agreement relating to such issuance, against payment of the consideration fixed therefor by the Board of Directors, the Common Stock will be validly issued, fully paid and non-assessable.

2. When (i) the terms of the Preferred Stock and of its issuance and sale have been duly established in conformity with the Company’s Amended and Restated Certificate of Incorporation, as amended and/or restated, and authorized and approved by all necessary action of the Board of Directors, so as not to violate any applicable law, rule or regulation or result in a default under or breach of any agreement or instrument binding upon the Company and so as to

Biogen Inc.

May 1, 2025

Page 3

comply with any requirement or restriction imposed by any court or governmental body having jurisdiction over the Company, (ii) a Certificate of Designations fixing and determining the terms of the Preferred Stock has been duly filed with the Secretary of State of the State of Delaware and (iii) the Preferred Stock has been duly executed, authenticated, issued and delivered as contemplated by the Registration Statement and any prospectus supplement relating thereto, and in accordance with such action of the Board of Directors and the terms of any underwriting agreement, Warrants or Warrant Agreement relating to such issuance, against payment of the consideration fixed therefor by the Board of Directors, the Preferred Stock will be validly issued, fully paid and non-assessable.

3. The Indenture has been duly authorized, executed and delivered by the Company and the Indenture has been qualified under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”).

4. When (i)(a) the terms of the Debt Securities and their issuance and sale and any supplemental indenture to be entered into in connection with the issuance of such Debt Securities have been duly authorized and approved by all necessary action of the Board of Directors and (b) the terms of such Debt Securities have been duly established in accordance with the Indenture and the applicable supplemental indenture relating to such Debt Securities so as not to violate any applicable law, rule or regulation or result in a default under or breach of any agreement or instrument binding upon the Company and so as to comply with any requirement or restriction imposed by any court or governmental body having jurisdiction over the Company, (ii) the supplemental indenture in respect of such Debt Securities has been duly executed and delivered and (iii) such Debt Securities have been duly executed, authenticated, issued and delivered as contemplated by the Registration Statement and any prospectus supplement relating thereto, and in accordance with the terms of the Indenture and the applicable supplemental indenture and any underwriting agreement, Warrants or Warrant Agreement relating to such issuance, against payment of the consideration fixed therefor by the Board of Directors, such Debt Securities will be validly issued and will constitute valid and binding obligations of the Company enforceable against the Company in accordance with their terms.

5. If any Debt Securities are convertible into Common Stock, when (i) the terms of the issuance of the Common Stock have been duly authorized and approved by all necessary action of the Board of Directors and (ii) the Common Stock has been issued upon conversion of such Debt Securities as contemplated by the Registration Statement and any prospectus supplement relating thereto, in accordance with the terms of such Debt Securities and the Indenture, so as not to violate any applicable law, rule or regulation or result in a default under or a violation of any agreement or instrument binding upon the Company and so as to comply with any applicable requirement or restriction imposed by any court or governmental authority having jurisdiction over the Company, the Common Stock so issued will be validly issued, fully paid and non-assessable.

Biogen Inc.

May 1, 2025

Page 4

6. When (i) the terms, and the execution and delivery, of the Warrants and any Warrant Agreement or Warrant Agreement relating to the Warrants and the terms of the issuance and sale of the Warrants and related matters have been duly authorized and approved by all necessary action of the Board of Directors, (ii) the Warrant Agreement or Warrant Agreement relating to the Warrants have been duly executed and delivered by the Company and such warrant agent as shall have been duly appointed by the Company, (iii) the terms of the Warrants have been established in accordance with the applicable Warrant Agreement, so as not to violate any applicable law, rule or regulation or result in a default under or a breach of any agreement or instrument binding upon the Company and so as to comply with any requirement or restriction imposed by any court or governmental body having jurisdiction over the Company and (iv) the Warrants or certificates representing the Warrants have been duly executed, authenticated, issued and delivered as contemplated by the Registration Statement and any prospectus supplement relating thereto, and in accordance with the terms of any Warrant Agreement and underwriting agreement relating to such issuance, against payment of the consideration fixed therefor by the Board of Directors, the Warrants will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

7. When (i) the terms, and the execution and delivery, of the Deposit Agreement relating to the Depositary Shares and the terms of the Depositary Shares and of their issuance and sale have been duly authorized and approved by all necessary action of the Board of Directors, (ii) the Deposit Agreement and the depositary receipts evidencing the Depositary Shares (the “Depositary Receipts”) have been duly authorized, executed and delivered by the Company and such depositary as shall have been duly appointed by the Company (the “Depositary”), (iii) the terms of the Depositary Shares and the Depositary Receipts have been established in accordance with the applicable Deposit Agreement, so as not to violate any applicable law, rule or regulation or result in a default under or breach of any agreement or instrument binding upon the Company and so as to comply with any applicable requirement or restriction imposed by any court or governmental authority having jurisdiction over the Company, (iv) the Preferred Stock relating to the Depositary Shares has been duly authorized and validly issued and is fully paid and non-assessable as contemplated in opinion paragraph 2 above and have been deposited with the Depositary under the applicable Deposit Agreement and (v) the Depositary Receipts have been duly executed, countersigned, registered and delivered as contemplated by the Registration Statement and any prospectus supplement related thereto, and in accordance with the terms of the Deposit Agreement and any underwriting agreement, Warrants or Warrant Agreements relating to such issuance, against payment of the consideration fixed therefor by the Board of Directors, the Depositary Receipts will be validly issued.

Our opinions set forth above are subject to the effects of (i) bankruptcy, insolvency, fraudulent conveyance, fraudulent transfer, reorganization and moratorium laws, and other similar laws relating to or affecting creditors’ rights or remedies generally, (ii) general equitable principles (whether considered in a proceeding in equity or at law) and (iii) concepts of good faith, reasonableness and fair dealing, and standards of materiality.

We express no opinion as to the laws of any jurisdiction other than the laws of the State of New York, the General Corporation Law of the State of Delaware (the “DGCL”) and the reported judicial decisions interpreting the DGCL, and the federal laws of the United States of America, each as currently in effect.

We express no opinion as to the application of the securities or blue sky laws of the several states to the sale of the Securities. Without limiting the generality of the foregoing, except as set forth herein, we express no opinion in connection with the matters contemplated in the Registration Statement, and no opinion may be implied or inferred, except as expressly set forth herein.

Biogen Inc.

May 1, 2025

Page 5

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to our firm under the heading “Legal Matters” in the Prospectus forming a part of thereof and in any amendments or supplements to the Registration Statement and Prospectus. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder.

Very truly yours,

/s/ Willkie Farr & Gallagher LLP

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-3 of Biogen Inc. of our report dated February 12, 2025 relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in Biogen Inc.’s Annual Report on Form 10-K for the year ended December 31, 2024. We also consent to the reference to us under the heading “Experts” in such Registration Statement.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

May 1, 2025

1

Exhibit 25.1

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM T-1

STATEMENT OF ELIGIBILITY

UNDER THE TRUST INDENTURE ACT OF 1939

OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION

(Exact name of Trustee as specified in its charter)

91-1821036

I.R.S. Employer Identification No.

David J Ganss

U.S. Bank Trust Company, National Association

1 Federal Street,

Boston, MA 02110

(617) 603-6568

(Name, address and telephone number of agent for service)

BIOGEN INC.

(Issuer with respect to the Securities)

Senior Note Debt Issuance

(Title of the Indenture Securities)

FORM T-1

Comptroller of the Currency

Washington, D.C.

Yes

None

SIGNATURE

Pursuant to the requirements of the Trust Indenture Act of 1939, as amended, the Trustee, U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, a national banking association organized and existing under the laws of the United States of America, has duly caused this statement of eligibility and qualification to be signed on its behalf by the undersigned, thereunto duly authorized, all in the City of Boston, State of Massachusetts on the 1st of May, 2025.

Exhibit 1

ARTICLES OF ASSOCIATION

OF

U. S. BANK TRUST COMPANY, NATIONAL ASSOCIATION

For the purpose of organizing an association (the “Association”) to perform any lawful activities of national banks, the undersigned enter into the following Articles of Association:

FIRST. The title of this Association shall be U. S. Bank Trust Company, National Association.

SECOND. The main office of the Association shall be in the city of Portland, county of Multnomah, state of Oregon. The business of the Association will be limited to fiduciary powers and the support of activities incidental to the exercise of those powers. The Association may not expand or alter its business beyond that stated in this article without the prior approval of the Comptroller of the Currency.

THIRD. The board of directors of the Association shall consist of not less than five nor more than twenty-five persons, the exact number to be fixed and determined from time to time by resolution of a majority of the full board of directors or by resolution of a majority of the shareholders at any annual or special meeting thereof. Each director shall own common or preferred stock of the Association or of a holding company owning the Association, with an aggregate par, fair market, or equity value of not less than $1,000, as of either (i) the date of purchase, (ii) the date the person became a director, or (iii) the date of that person’s most recent election to the board of directors, whichever is more recent. Any combination of common or preferred stock of the Association or holding company may be used.

Any vacancy in the board of directors may be filled by action of a majority of the remaining directors between meetings of shareholders. The board of directors may increase the number of directors up to the maximum permitted by law. Terms of directors, including directors selected to fill vacancies, shall expire at the next regular meeting of shareholders at which directors are elected, unless the directors resign or are removed from office. Despite the expiration of a director’s term, the director shall continue to serve until his or her successor is elected and qualified or until there is a decrease in the number of directors and his or her position is eliminated.

Honorary or advisory members of the board of directors, without voting power or power of final decision in matters concerning the business of the Association, may be appointed by resolution of a majority of the full board of directors, or by resolution of shareholders at any annual or special meeting. Honorary or advisory directors shall not be counted to determined the number of directors of the Association or the presence of a quorum in connection with any board action, and shall not be required to own qualifying shares.

FOURTH. There shall be an annual meeting of the shareholders to elect directors and transact whatever other business may be brought before the meeting. It shall be held at the main office or any other convenient place the board of directors may designate, on the day of each year specified therefor in the Bylaws, or if that day falls on a legal holiday in the state in which the

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Association is located, on the next following banking day. If no election is held on the day fixed or in the event of a legal holiday on the following banking day, an election may be held on any subsequent day within 60 days of the day fixed, to be designated by the board of directors, or, if the directors fail to fix the day, by shareholders representing two-thirds of the shares issued and outstanding. In all cases, at least 10 days’ advance notice of the meeting shall be given to the shareholders by first-class mail.

In all elections of directors, the number of votes each common shareholder may cast will be determined by multiplying the number of shares he or she owns by the number of directors to be elected. Those votes may be cumulated and cast for a single candidate or may be distributed among two or more candidates in the manner selected by the shareholder. On all other questions, each common shareholder shall be entitled to one vote for each share of stock held by him or her.

A director may resign at any time by delivering written notice to the board of directors, its chairperson, or to the Association, which resignation shall be effective when the notice is delivered unless the notice specifies a later effective date.

A director may be removed by the shareholders at a meeting called to remove him or her, when notice of the meeting stating that the purpose or one of the purposes is to remove him or her is provided, if there is a failure to fulfill one of the affirmative requirements for qualification, or for cause; provided, however, that a director may not be removed if the number of votes sufficient to elect him or her under cumulative voting is voted against his or her removal.

FIFTH. The authorized amount of capital stock of the Association shall be 1,000,000 shares of common stock of the par value of ten dollars ($10) each; but said capital stock may be increased or decreased from time to time, according to the provisions of the laws of the United States. The Association shall have only one class of capital stock.

No holder of shares of the capital stock of any class of the Association shall have any preemptive or preferential right of subscription to any shares of any class of stock of the Association, whether now or hereafter authorized, or to any obligations convertible into stock of the Association, issued, or sold, nor any right of subscription to any thereof other than such, if any, as the board of directors, in its discretion, may from time to time determine and at such price as the board of directors may from time to time fix.

Transfers of the Association’s stock are subject to the prior written approval of a federal depository institution regulatory agency. If no other agency approval is required, the approval of the Comptroller of the Currency must be obtained prior to any such transfers.

Unless otherwise specified in the Articles of Association or required by law, (1) all matters requiring shareholder action, including amendments to the Articles of Association must be approved by shareholders owning a majority voting interest in the outstanding voting stock, and (2) each shareholder shall be entitled to one vote per share.

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Unless otherwise specified in the Articles of Association or required by law, all shares of voting stock shall be voted together as a class, on any matters requiring shareholder approval.

Unless otherwise provided in the Bylaws, the record date for determining shareholders entitled to notice of and to vote at any meeting is the close of business on the day before the first notice is mailed or otherwise sent to the shareholders, provided that in no event may a record date be more than 70 days before the meeting.

The Association, at any time and from time to time, may authorize and issue debt obligations, whether subordinated, without the approval of the shareholders. Obligations classified as debt, whether subordinated, which may be issued by the Association without the approval of shareholders, do not carry voting rights on any issue, including an increase or decrease in the aggregate number of the securities, or the exchange or reclassification of all or part of securities into securities of another class or series.

SIXTH. The board of directors shall appoint one of its members president of this Association and one of its members chairperson of the board and shall have the power to appoint one or more vice presidents, a secretary who shall keep minutes of the directors’ and shareholders’ meetings and be responsible for authenticating the records of the Association, and such other officers and employees as may be required to transact the business of this Association. A duly appointed officer may appoint one or more officers or assistant officers if authorized by the board of directors in accordance with the Bylaws.

The board of directors shall have the power to:

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SEVENTH. The board of directors shall have the power to change the location of the main office to any authorized branch within the limits of the city of Portland, Oregon, without the approval of the shareholders, or with a vote of shareholders owning two-thirds of the stock of the Association for a location outside such limits and upon receipt of a certificate of approval from the Comptroller of the Currency, to any other location within or outside the limits of the city of Portland, Oregon, but not more than thirty miles beyond such limits. The board of directors shall have the power to establish or change the location of any office or offices of the Association to any other location permitted under applicable law, without approval of shareholders, subject to approval by the Comptroller of the Currency.

EIGHTH. The corporate existence of this Association shall continue until termination according to the laws of the United States.

NINTH. The board of directors of the Association, or any shareholder owning, in the aggregate, not less than 25 percent of the stock of the Association, may call a special meeting of shareholders at any time. Unless otherwise provided by the Bylaws or the laws of the United States, or waived by shareholders, a notice of the time, place, and purpose of every annual and special meeting of the shareholders shall be given by first-class mail, postage prepaid, mailed at least 10, and no more than 60, days prior to the date of the meeting to each shareholder of record at his/her address as shown upon the books of the Association. Unless otherwise provided by the Bylaws, any action requiring approval of shareholders must be effected at a duly called annual or special meeting.

TENTH. These Articles of Association may be amended at any regular or special meeting of the shareholders by the affirmative vote of the holders of a majority of the stock of the Association, unless the vote of the holders of a greater amount of stock is required by law, and in that case by the vote of the holders of such greater amount; provided, that the scope of the Association’s activities and services may not be expanded without the prior written approval of the Comptroller of the Currency. The Association’s board of directors may propose one or more amendments to the Articles of Association for submission to the shareholders.

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In witness whereof, we have hereunto set our hands this 11^th of June, 1997.

Exhibit 2

		Office of the Comptroller of the Currency
				Washington, DC 20219

CERTIFICATE OF CORPORATE EXISTENCE AND FIDUCIARY POWERS

I, Michael J. Hsu, Acting Comptroller of the Currency, do hereby certify that:

1. The Comptroller of the Currency, pursuant to Revised Statutes 324, et seq, as amended, and 12 USC 1, et seq, as amended, has possession, custody, and control of all records pertaining to the chartering, regulation, and supervision of all national banking associations.

2. “U.S. Bank Trust Company National Association,” Portland, Oregon (CharterNo. 23412), is a national banking association formed under the laws of the United States and is authorized thereunder to transact the business of banking and exercise fiduciary powers on the date of this certificate.

IN TESTIMONY WHEREOF, today, December 11, 2024, I have hereunto subscribed my name and caused my seal of office to be affixed to these presents at the U.S. Department of the Treasury, in the City of Washington, District of Columbia.

		Acting Comptroller of the Currency

2025-00299-C

Exhibit 4

U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION

AMENDED AND RESTATED BYLAWS

ARTICLE I

Meetings of Shareholders

Section 1.1. Annual Meeting. The annual meeting of the shareholders, for the election of directors and the transaction of any other proper business, shall be held at a time and place as the Chairman or President may designate. Notice of such meeting shall be given not less than ten (10) days or more than sixty (60) days prior to the date thereof, to each shareholder of the Association, unless the Office of the Comptroller of the Currency (the “OCC”) determines that an emergency circumstance exists. In accordance with applicable law, the sole shareholder of the Association is permitted to waive notice of the meeting. If, for any reason, an election of directors is not made on the designated day, the election shall be held on some subsequent day, as soon thereafter as practicable, with prior notice thereof. Failure to hold an annual meeting as required by these Bylaws shall not affect the validity of any corporate action or work a forfeiture or dissolution of the Association.

Section 1.2. Special Meetings. Except as otherwise specially provided by law, special meetings of the shareholders may be called for any purpose, at any time by a majority of the board of directors (the “Board”), or by any shareholder or group of shareholders owning at least ten percent of the outstanding stock. Every such special meeting, unless otherwise provided by law, shall be called upon not less than ten (10) days nor more than sixty (60) days prior notice stating the purpose of the meeting.

Section 1.3. Nominations for Directors. Nominations for election to the Board may be made by the Board or by any shareholder.

Section 1.4. Proxies. Shareholders may vote at any meeting of the shareholders by proxies duly authorized in writing. Proxies shall be valid only for one meeting and any adjournments of such meeting and shall be filed with the records of the meeting.

Section 1.5. Record Date. The record date for determining shareholders entitled to notice and to vote at any meeting will be thirty days before the date of such meeting, unless otherwise determined by the Board.

Section 1.6. Quorum and Voting. A majority of the outstanding capital stock, represented in person or by proxy, shall constitute a quorum at any meeting of shareholders, unless otherwise provided by law, but less than a quorum may adjourn any meeting, from time to time, and the meeting may be held as adjourned without further notice. A majority of the votes cast shall decide every question or matter submitted to the shareholders at any meeting, unless otherwise provided by law or by the Articles of Association.

Section 1.7. Inspectors. The Board may, and in the event of its failure so to do, the Chairman of the Board may appoint Inspectors of Election who shall determine the presence of quorum, the validity of proxies, and the results of all elections and all other matters voted upon by shareholders at all annual and special meetings of shareholders.

Section 1.8. Waiver and Consent. The shareholders may act without notice or a meeting by a unanimous written consent by all shareholders.

Section 1.9. Remote Meetings. The Board shall have the right to determine that a shareholder meeting not be held at a place, but instead be held solely by means of remote communication in the manner and to the extent permitted by the General Corporation Law of the State of Delaware.

ARTICLE II

Directors

Section 2.1. Board of Directors. The Board shall have the power to manage and administer the business and affairs of the Association. Except as expressly limited by law, all corporate powers of the Association shall be vested in and may be exercised by the Board.

Section 2.2. Term of Office. The directors of this Association shall hold office for one year and until their successors are duly elected and qualified, or until their earlier resignation or removal.

Section 2.3. Powers. In addition to the foregoing, the Board shall have and may exercise all of the powers granted to or conferred upon it by the Articles of Association, the Bylaws and by law.

Section 2.4. Number. As provided in the Articles of Association, the Board of this Association shall consist of no less than five nor more than twenty-five members, unless the OCC has exempted the Association from the twenty-five- member limit. The Board shall consist of a number of members to be fixed and determined from time to time by resolution of the Board or the shareholders at any meeting thereof, in accordance with the Articles of Association. Between meetings of the shareholders held for the purpose of electing directors, the Board

by a majority vote of the full Board may increase the size of the Board but not to more than a total of twenty-five directors, and fill any vacancy so created in the Board; provided that the Board may increase the number of directors only by up to two directors, when the number of directors last elected by shareholders was fifteen or fewer, and by up to four directors, when the number of directors last elected by shareholders was sixteen or more. Each director shall own a qualifying equity interest in the Association or a company that has control of the Association in each case as required by applicable law. Each director shall own such qualifying equity interest in his or her own right and meet any minimum threshold ownership required by applicable law.

Section 2.5. Organization Meeting. The newly elected Board shall meet for the purpose of organizing the new Board and electing and appointing such officers of the Association as may be appropriate. Such meeting shall be held on the day of the election or as soon thereafter as practicable, and, in any event, within thirty days thereafter, at such time and place as the Chairman or President may designate. If, at the time fixed for such meeting, there shall not be a quorum present, the directors present may adjourn the meeting until a quorum is obtained.

Section 2.6. Regular Meetings. The regular meetings of the Board shall be held, without notice, as the Chairman or President may designate and deem suitable.

Section 2.7. Special Meetings. Special meetings of the Board may be called at any time, at any place and for any purpose by the Chairman of the Board or the President of the Association, or upon the request of a majority of the entire Board. Notice of every special meeting of the Board shall be given to the directors at their usual places of business, or at such other addresses as shall have been furnished by them for the purpose. Such notice shall be given at least twelve hours (three hours if meeting is to be conducted by conference telephone) before the meeting by telephone or by being personally delivered, mailed, or electronically delivered. Such notice need not include a statement of the business to be transacted at, or the purpose of, any such meeting.

Section 2.8. Quorum and Necessary Vote. A majority of the directors shall constitute a quorum at any meeting of the Board, except when otherwise provided by law; but less than a quorum may adjourn any meeting, from time to time, and the meeting may be held as adjourned without further notice. Unless otherwise provided by law or the Articles or Bylaws of this Association, once a quorum is established, any act by a majority of those directors present and voting shall be the act of the Board.

Section 2.9. Written Consent. Except as otherwise required by applicable laws and regulations, the Board may act without a meeting by a unanimous written consent by all directors, to be filed with the Secretary of the Association as part of the corporate records.

Section 2.10. Remote Meetings. Members of the Board, or of any committee thereof, may participate in a meeting of such Board or committee by means of conference telephone, video or similar communications equipment by means of which all persons participating in the meeting can hear each other and such participation shall constitute presence in person at such meeting.

Section 2.11. Vacancies. When any vacancy occurs among the directors, the remaining members of the Board may appoint a director to fill such vacancy at any regular meeting of the Board, or at a special meeting called for that purpose.

ARTICLE III

Committees

Section 3.1. Advisory Board of Directors. The Board may appoint persons, who need not be directors, to serve as advisory directors on an advisory board of directors established with respect to the business affairs of either this Association alone or the business affairs of a group of affiliated organizations of which this Association is one. Advisory directors shall have such powers and duties as may be determined by the Board, provided, that the Board’s responsibility for the business and affairs of this Association shall in no respect be delegated or diminished.

Section 3.2. Trust Audit Committee. At least once during each calendar year, the Association shall arrange for a suitable audit (by internal or external auditors) of all significant fiduciary activities under the direction of its trust audit committee, a function that will be fulfilled by the Audit Committee of the financial holding company that is the ultimate parent of this Association. The Association shall note the results of the audit (including significant actions taken as a result of the audit) in the minutes of the Board. In lieu of annual audits, the Association may adopt a continuous audit system in accordance with 12 C.F.R. § 9.9(b).

The Audit Committee of the financial holding company that is the ultimate parent of this Association, fulfilling the function of the trust audit committee:

(1) Must not include any officers of the Association or an affiliate who participate significantly in the administration of the Association’s fiduciary activities; and

(2) Must consist of a majority of members who are not also members of any committee to which the Board has delegated power to manage and control the fiduciary activities of the Association.

Section 3.3. Executive Committee. The Board may appoint an Executive Committee which shall consist of at least three directors and which shall have, and may exercise, to the extent permitted by applicable law, all the powers of the Board between meetings of the Board or otherwise when the Board is not meeting.

Section 3.4. Trust Management Committee. The Board of this Association shall appoint a Trust Management Committee to provide oversight of the fiduciary activities of the Association. The Trust Management Committee shall determine policies governing fiduciary activities. The Trust Management Committee or such sub-committees, officers or others as may be duly designated by the Trust Management Committee shall oversee the processes related to fiduciary activities to assure conformity with fiduciary policies it establishes, including ratifying the acceptance and the closing out or relinquishment of all trusts. The Trust Management Committee will provide regular reports of its activities to the Board.

Section 3.5. Other Committees. The Board may appoint, from time to time, committees of one or more persons who need not be directors, for such purposes and with such powers as the Board may determine; however, the Board will not delegate to any committee any powers or responsibilities that it is prohibited from delegating under any law or regulation. In addition, either the Chairman or the President may appoint, from time to time, committees of one or more officers, employees, agents or other persons, for such purposes and with such powers as either the Chairman or the President deems appropriate and proper. Whether appointed by the Board, the Chairman, or the President, any such committee shall at all times be subject to the direction and control of the Board.

Section 3.6. Meetings, Minutes and Rules. An advisory board of directors and/or committee shall meet as necessary in consideration of the purpose of the advisory board of directors or committee, and shall maintain minutes in sufficient detail to indicate actions taken or recommendations made; unless required by the members, discussions, votes or other specific details need not be reported. An advisory board of directors or a committee may, in consideration of its purpose, adopt its own rules for the exercise of any of its functions or authority.

ARTICLE IV

Officers

Section 4.1. Chairman of the Board. The Board may appoint one of its members to be Chairman of the Board to serve at the pleasure of the Board. The Chairman shall supervise the carrying out of the policies adopted or approved by the Board; shall have general executive powers, as well as the specific powers conferred by these Bylaws; and shall also have and may exercise such powers and duties as from time to time may be conferred upon or assigned by the Board.

Section 4.2. President. The Board may appoint one of its members to be President of the Association. In the absence of the Chairman, the President shall preside at any meeting of the Board. The President shall have general executive powers, and shall have and may exercise any and all other powers and duties pertaining by law, regulation or practice, to the office of President, or imposed by these Bylaws. The President shall also have and may exercise such powers and duties as from time to time may be conferred or assigned by the Board.

Section 4.3. Vice President. The Board may appoint one or more Vice Presidents who shall have such powers and duties as may be assigned by the Board and to perform the duties of the President on those occasions when the President is absent, including presiding at any meeting of the Board in the absence of both the Chairman and President.

Section 4.4. Secretary. The Board shall appoint a Secretary, or other designated officer who shall be Secretary of the Board and of the Association, and shall keep accurate minutes of all meetings. The Secretary shall attend to the giving of all notices required by these Bylaws to be given; shall be custodian of the corporate seal, records, documents and papers of the Association; shall provide for the keeping of proper records of all transactions of the Association; shall, upon request, authenticate any records of the Association; shall have and may exercise any and all other powers and duties pertaining by law, regulation or practice, to the Secretary, or imposed by these Bylaws; and shall also perform such other duties as may be assigned from time to time by the Board. The Board may appoint one or more Assistant Secretaries with such powers and duties as the Board, the President or the Secretary shall from time to time determine.

Section 4.5. Other Officers. The Board may appoint, and may authorize the Chairman, the President or any other officer to appoint, any officer as from time to time may appear to the Board, the Chairman, the President or such other officer to be required or desirable to transact the business of the Association. Such officers shall exercise such powers and perform such duties as pertain to their several offices, or as may be conferred upon or assigned to them by these Bylaws, the Board, the Chairman, the President or such other authorized officer. Any person may hold two offices.

Section 4.6. Tenure of Office. The Chairman or the President and all other officers shall hold office until their respective successors are elected and qualified or until their earlier death, resignation, retirement, disqualification or removal from office, subject to the right of the Board or authorized officer to discharge any officer at any time.

ARTICLE V

Stock

Section 5.1. The Board may authorize the issuance of stock either in certificated or in uncertificated form. Certificates for shares of stock shall be in such form as the Board may from time to time prescribe. If the Board issues certificated stock, the certificate shall be signed by the President, Secretary or any other such officer as the Board so determines. Shares of stock shall be transferable on the books of the Association, and a transfer book shall be kept in which all transfers of stock shall be recorded. Every person becoming a shareholder by such transfer shall, in proportion to such person’s shares, succeed to all rights of the prior holder of such shares. Each certificate of stock shall recite on its face that the stock represented thereby is transferable only upon the books of the Association properly endorsed. The Board may impose conditions upon the transfer of the stock reasonably calculated to simplify the work of the Association for stock transfers, voting at shareholder meetings, and related matters, and to protect it against fraudulent transfers.

ARTICLE VI

Corporate Seal

Section 6.1. The Association shall have no corporate seal; provided, however, that if the use of a seal is required by, or is otherwise convenient or advisable pursuant to, the laws or regulations of any jurisdiction, the following seal may be used, and the Chairman, the President, the Secretary and any Assistant Secretary shall have the authority to affix such seal:

ARTICLE VII

Miscellaneous Provisions

Section 7.1. Execution of Instruments. All agreements, checks, drafts, orders, indentures, notes, mortgages, deeds, conveyances, transfers, endorsements, assignments, certificates, declarations, receipts, discharges, releases, satisfactions, settlements, petitions, schedules, accounts, affidavits, bonds, undertakings, guarantees, proxies and other instruments or documents may be signed, countersigned, executed, acknowledged, endorsed, verified, delivered or accepted on behalf of the Association, whether in a fiduciary capacity or otherwise, by any officer of the Association, or such employee or agent as may be designated from time to time by the Board by resolution, or by the Chairman or the President by written instrument, which resolution or instrument shall be certified as in effect by the Secretary or an Assistant Secretary of the Association. The provisions of this section are supplementary to any other provision of the Articles of Association or Bylaws.

Section 7.2. Records. The Articles of Association, the Bylaws as revised or amended from time to time and the proceedings of all meetings of the shareholders, the Board, and standing committees of the Board, shall be recorded in appropriate minute books provided for the purpose. The minutes of each meeting shall be signed by the Secretary, or other officer appointed to act as Secretary of the meeting.

Section 7.3. Trust Files. There shall be maintained in the Association files all fiduciary records necessary to assure that its fiduciary responsibilities have been properly undertaken and discharged.

Section 7.4. Trust Investments. Funds held in a fiduciary capacity shall be invested according to the instrument establishing the fiduciary relationship and according to law. Where such instrument does not specify the character and class of investments to be made and does not vest in the Association a discretion in the matter, funds held pursuant to such instrument shall be invested in investments in which corporate fiduciaries may invest under law.

Section 7.5. Notice. Whenever notice is required by the Articles of Association, the Bylaws or law, such notice shall be by mail, postage prepaid, e- mail, in person, or by any other means by which such notice can reasonably be expected to be received, using the address of the person to receive such notice, or such other personal data, as may appear on the records of the Association. Except where specified otherwise in these Bylaws, prior notice shall be proper if given not more than 30 days nor less than 10 days prior to the event for which notice is given.

ARTICLE VIII

Indemnification

Section 8.1. The Association shall indemnify such persons for such liabilities in such manner under such circumstances and to such extent as permitted by Section 145 of the Delaware General Corporation Law, as now enacted or hereafter amended. The Board may authorize the purchase and maintenance of insurance and/or the execution of individual agreements for the purpose of such indemnification, and the Association shall advance all reasonable costs and expenses (including attorneys’ fees) incurred in defending any action, suit or proceeding to all persons entitled to indemnification under this Section 8.1. Such insurance shall be consistent with the requirements of 12 C.F.R. § 7.2014 and shall exclude coverage of liability for a formal order assessing civil money penalties against an institution-affiliated party, as defined at 12 U.S.C. § 1813(u).

Section 8.2. Notwithstanding Section 8.1, however, (a) any indemnification payments to an institution-affiliated party, as defined at 12 U.S.C. § 1813(u), for an administrative proceeding or civil action initiated by a federal banking agency, shall be reasonable and consistent with the requirements of 12 U.S.C. § 1828(k) and the implementing regulations thereunder; and (b) any indemnification payments and advancement of costs and expenses to an institution-affiliated party, as defined at 12 U.S.C. § 1813(u), in cases involving an administrative proceeding or civil action not initiated by a federal banking agency, shall be in accordance with Delaware General Corporation Law and consistent with safe and sound banking practices.

ARTICLE IX

Bylaws: Interpretation and Amendment

Section 9.1. These Bylaws shall be interpreted in accordance with and subject to appropriate provisions of law, and may be added to, altered, amended, or repealed, at any regular or special meeting of the Board.

Section 9.2. A copy of the Bylaws and all amendments shall at all times be kept in a convenient place at the principal office of the Association, and shall be open for inspection to all shareholders during Association hours.

ARTICLE X

Miscellaneous Provisions

Section 10.1. Fiscal Year. The fiscal year of the Association shall begin on the first day of January in each year and shall end on the thirty-first day of December following.

Section 10.2. Governing Law. This Association designates the Delaware General Corporation Law, as amended from time to time, as the governing law for its corporate governance procedures, to the extent not inconsistent with Federal banking statutes and regulations or bank safety and soundness.

***

(February 8, 2021)

Exhibit 6

CONSENT

In accordance with Section 321(b) of the Trust Indenture Act of 1939, the undersigned, U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION hereby consents that reports of examination of the undersigned by Federal, State, Territorial or District authorities may be furnished by such authorities to the Securities and Exchange Commission upon its request therefor.

Dated: May 1, 2025

Exhibit 7

U.S. Bank Trust Company, National Association

Statement of Financial Condition

as of 12/31/2024

($000’s)