Biogen (NASDAQ: BIIB) deems Apellis acquisition not significant

Rhea-AI Filing Summary

Biogen Inc. filed an amended report to update disclosure related to its acquisition of Apellis Pharmaceuticals, Inc. After further analysis, Biogen determined that this merger does not qualify as a “significant” acquisition under Regulation S-X. Because of this, Biogen states that audited financial statements for Apellis and related pro forma financial information are not required. The amendment removes earlier references to incorporating Apellis financials and to a future filing of pro forma data, while confirming that all other information from the original report remains unchanged.

8-K Event Classification

Item 9.01 — Financial Statements and Exhibits

1 item

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

Merger agreement date: March 31, 2026 Original report date: May 14, 2026 Amendment signature date: June 10, 2026

3 metrics

Merger agreement date March 31, 2026 Agreement and Plan of Merger among Biogen, Apellis and Aspen Purchaser Sub

Original report date May 14, 2026 Date Biogen filed the original report on the Apellis acquisition

Amendment signature date June 10, 2026 Date the amended report was signed on behalf of Biogen

Key Terms

pro forma financial information, significant acquisition, Regulation S-X, Item 9.01(a), +1 more

5 terms

pro forma financial information financial

"pro forma financial information required by Item 9.01(b) of"

Pro forma financial information are adjusted financial numbers that show how a company’s results might look after a specific event or after removing one-time items, like a cleaned-up or “what if” version of its earnings. Investors use these figures to compare performance, judge future profitability, or evaluate the impact of mergers, restructurings or large transactions, but they require scrutiny because adjustments can make results look rosier than standard accounting statements.

significant acquisition regulatory

"the Merger was not a “significant” acquisition as defined in Regulation S-X"

Regulation S-X regulatory

"not a “significant” acquisition as defined in Regulation S-X"

A set of U.S. securities rules that prescribes how public companies must prepare, present and have audited their financial statements and related exhibits. It lays out formats, required schedules and minimum disclosure standards so financial reports follow a consistent structure. For investors, this consistency and verification act like a standard recipe and inspection checklist, making financial statements easier to compare, trust and use for valuation decisions.

Item 9.01(a) regulatory

"financial statements required by Item 9.01(a) of"

Item 9.01(b) regulatory

"pro forma financial information required by Item 9.01(b) of"

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Understanding 8-K Material Events →

true Amendment No. 1 0000875045 0000875045 2026-05-14 2026-05-14 iso4217:USD xbrli:shares iso4217:USD xbrli:shares

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 ☐

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 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

FAQ

What did Biogen Inc. change in this amended 8-K/A filing about Apellis?

Biogen updated its prior disclosure about acquiring Apellis Pharmaceuticals. After review, it concluded the deal is not a “significant” acquisition, so separate Apellis financial statements and pro forma financial information are no longer required and references to those materials were removed.

Why does Biogen say the Apellis acquisition is not a significant acquisition?

Biogen determined the Apellis merger does not meet the definition of a “significant” acquisition under Regulation S-X. Because it falls below those regulatory thresholds, Biogen is not required to provide separate Apellis financial statements or related pro forma financial information in this report.

Does Biogen still plan to file pro forma financial information for the Apellis deal?

No. Biogen initially expected to provide pro forma financial information for the Apellis merger in a later amendment. After further analysis, it concluded those pro forma figures are not required and has removed references to any future pro forma filing.

What happens to the rest of Biogen’s original disclosure on the Apellis merger?

Biogen states that, aside from removing references to Apellis financial statements and pro forma information, all other disclosures from the original report remain unchanged. The amendment is limited to clarifying that the financial statement requirements under Item 9.01 do not apply.

Which specific SEC reporting items does Biogen now mark as not applicable?

Biogen indicates that Item 9.01(a), covering financial statements of businesses acquired, and Item 9.01(b), covering pro forma financial information, are not applicable. This reflects its conclusion that the Apellis acquisition is not significant under the applicable SEC accounting rules.

Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL SCHEMA FILE 2.9 KB
• EX-101 XBRL LABEL FILE 34.1 KB
• EX-101 XBRL PRESENTATION FILE 22.2 KB