[SCHEDULE 13D/A] Sage Therapeutics, Inc SEC Filing

Rhea-AI Filing Summary

Biogen Inc. and subsidiary Biogen MA Inc. have fully divested their stake in Sage Therapeutics (SAGE). Amendment No. 2 to their Schedule 13D reports that the companies owned 6,241,473 common shares—9.941 % of Sage’s 62,784,397 outstanding shares—on 28 Jul 2025. On 29 Jul 2025 they sold every share in a single block trade at $8.53 per share, reducing ownership to 0 %. Because of this sale, the filers now hold no voting or dispositive power over Sage stock and formally ceased to be beneficial owners of more than 5 % on 29 Jul 2025. The amendment updates prior Schedule 13D filings dated 10 Jan 2024 and 21 Jul 2025 and contains no additional transactions, legal proceedings or contingent arrangements.

Positive

• None.

Negative

• Biogen sold its entire 9.941 % stake in SAGE at $8.53 per share, leaving Sage without a major strategic shareholder.
• Reporting persons now own 0 % of outstanding shares, removing potential voting support and future capital backing.

Insights

Equity Analyst

TL;DR: Biogen’s 10 % exit removes a strategic holder, likely pressuring SAGE shares and sentiment.

Biogen’s disposal of 6.24 million shares eliminates a near-10 % position acquired less than two years ago, signalling a decisive break with Sage. While the filing cites no motives, the complete sale at $8.53 suggests limited confidence in near-term value creation and removes a potential source of follow-on capital. The market may interpret the move as a negative read-through for Sage’s pipeline collaborations and future financing flexibility.

Corporate Governance Specialist

TL;DR: Loss of >5 % holder shifts SAGE’s ownership base; governance influence fades.

By falling below the 5 % threshold, Biogen relinquishes Schedule 13D reporting duties and any leverage it held in shareholder matters. Sage’s institutional ownership profile becomes more fragmented, potentially increasing volatility around strategic decisions and proxy votes. No standstill or other restrictive covenants are disclosed, so Biogen retains freedom to re-enter or remain absent.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 2)

Sage Therapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

78667J108

(CUSIP Number)

Wendell Taylor, Secretary
Biogen Inc., 225 Binney Street
Cambridge, MA, 02142
(617) 679-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

07/30/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 78667J108

1

Name of reporting person

Biogen Inc.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP No. 78667J108

1

Name of reporting person

Biogen MA Inc.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

MASSACHUSETTS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: Sage Therapeutics, Inc.
(c)	Address of Issuer's Principal Executive Offices: 55 Cambridge Parkway, Cambridge, MASSACHUSETTS , 02142.
Item 1 Comment: The following constitutes Amendment No. 2 to the Schedule 13D filed by the undersigned ("Amendment No. 2") on January 10, 2024, as amended by Amendment No. 1 on July 21, 2025. This Amendment No. 2 amends the Schedule 13D as specifically set forth herein.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5 is hereby amended and restated in its entirety as follows: As of July 28, 2025, the aggregate number of shares of Common Stock beneficially owned by the Reporting Persons was 6,241,473.00 shares, representing 9.941% of the 62,784,397 issued and outstanding shares of Common Stock of the Issuer as of July 23, 2025 (as disclosed in the Issuer's most recent quarterly report on Form 10-Q filed on July 30, 2025). On July 29, 2025, the Reporting Persons sold all of their shares of Common Stock at a price per share of $8.53 in a block trade. As of the date of this filing, the Reporting Persons beneficially own no shares of Common Stock, representing 0.00% of the issued and outstanding shares of Common Stock. As of the date of this filing, the Reporting Persons have no powers to vote, or to direct the vote of, or to dispose, or to direct the disposition of, shares of Common Stock.
(b)	Item 5(a) of this Schedule 13D is incorporated by reference into this Item 5(b).
(c)	Item 5(a) of this Schedule 13D is incorporated by reference into this Item 5(c).
(d)	Not applicable.
(e)	On July 29, 2025, the Reporting Persons ceased to be the beneficial owners of more than five percent of Common Stock.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Biogen Inc.

Signature:	/s/ Michael Dambach
Name/Title:	Michael Dambach / Treasurer
Date:	07/30/2025

Biogen MA Inc.

Signature:	/s/ Michael Dambach
Name/Title:	Michael Dambach / Treasurer
Date:	07/30/2025

FAQ

How many Sage Therapeutics (SAGE) shares did Biogen sell?

Biogen sold 6,241,473 Sage common shares.

At what price did Biogen exit its position in SAGE?

The shares were sold in a block trade at $8.53 per share.

What is Biogen’s current ownership percentage in Sage Therapeutics after the sale?

Biogen now owns 0 % of Sage’s outstanding common stock.

When did Biogen cease to be a 5 % beneficial owner of SAGE?

Biogen fell below the 5 % threshold on 29 Jul 2025.

Does Biogen retain any voting or dispositive power over SAGE shares?

No. The filing states Biogen has no voting or dispositive power over Sage common stock.