Form 8-K/A

8-K/A — BIOGEN INC.

Accession: 0000950157-26-000699

Filed: 2026-06-10

Period: 2026-05-14

CIK: 0000875045

SIC: 2836 (BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES))

Item: Financial Statements and Exhibits

Documents

8-K/A — form8-ka.htm (Primary)

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8-K/A — CURRENT REPORT

8-K/A (Primary)

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Form 8-K

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Amendment No. 1

0000875045

2026-05-14

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UNITED

STATES

SECURITIES

AND EXCHANGE COMMISSION

Washington,

D.C. 20549

_________________

FORM

8-K/A

(Amendment

No. 1)

_________________

CURRENT

REPORT

Pursuant

to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date

of Report (Date of earliest event reported): May

14, 2026

_______________________________

Biogen

Inc.

(Exact

name of registrant as specified in its charter)

_______________________________

Delaware

0-19311

33-0112644

(State or Other Jurisdiction

(Commission

(I.R.S. Employer

of Incorporation)

File Number)

Identification No.)

225

Binney Street, Cambridge,

Massachusetts

02142

(Address

of Principal Executive Offices) (Zip Code)

Registrant’s

telephone number, including area code: (617)

679-2000

Not

Applicable

(Former

name or former address, if changed since last report)

Check

the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under

any of the following provisions:

☐

Written communications

pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material

pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement

communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement

communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities

registered pursuant to Section 12(b) of the Act:

Title

of each class

Trading

Symbol(s)

Name

of each exchange on which registered

Common

Stock, $0.0005 par value per share

BIIB

The

Nasdaq Global Select Market

Indicate

by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405

of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging

growth company ☐

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 13(a) of the Exchange Act. ☐

Explanatory

Note

On May 14,

2026, Biogen Inc., a Delaware corporation (“Biogen”), filed a Current Report on Form 8-K (the “Original Report”)

with the U.S. Securities and Exchange Commission. The Original Report disclosed, among other things, the consummation of Biogen’s

acquisition of Apellis Pharmaceuticals, Inc., a Delaware corporation (“Apellis”), as contemplated by the Agreement and Plan

of Merger, dated March 31, 2026, by and among Biogen, Apellis and Aspen Purchaser Sub, Inc., a Delaware corporation and a wholly owned

subsidiary of Biogen (the “Merger”).

Biogen also

disclosed in the Original Report that pro forma financial information required by Item 9.01(b) of Form 8-K relating to the Merger would

be filed by amendment to the Original Report no later than 71 calendar days after the date on which the Original Report was required

to be filed.

Subsequent

to the filing of the Original Report and upon further analysis, Biogen has determined that financial statements required by Item 9.01(a)

of Form 8-K and pro forma financial information required by Item 9.01(b) of Form 8-K, in each case, relating to the Merger are not required

because the Merger was not a “significant” acquisition as defined in Regulation S-X. Accordingly, Biogen hereby amends the

Original Report to remove references to the incorporation by reference of financial statements of Apellis under Item 9.01(a) and the

subsequent filing of pro forma financial information required by Item 9.01(b), in each case, relating to the Merger.

Except as

provided herein, the disclosures made in the Original Report remain unchanged.

Item 9.01

Financial Statements and Exhibits.

(a) Financial

statements of businesses acquired.

Not applicable.

(b) Pro

forma financial information.

Not applicable.

SIGNATURES

Pursuant

to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by

the undersigned, hereunto duly authorized.

Biogen Inc.

Date: June 10, 2026

By:

/s/

Wendell Taylor

Name:

Wendell

Taylor

Title:

Secretary

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May 14, 2026

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Amendment Description

Amendment No. 1

Document Period End Date

May 14, 2026

Entity File Number

0-19311

Entity Registrant Name

Biogen

Inc.

Entity Central Index Key

0000875045

Entity Tax Identification Number

33-0112644

Entity Incorporation, State or Country Code

Entity Address, Address Line One

225

Binney Street

Entity Address, City or Town

Cambridge

Entity Address, State or Province

Entity Address, Postal Zip Code

02142

City Area Code

(617)

Local Phone Number

679-2000

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common

Stock, $0.0005 par value per share

Trading Symbol

BIIB

Security Exchange Name

NASDAQ

Entity Emerging Growth Company

false

Entity Information, Former Legal or Registered Name

Not

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