Institutional net value declined by $340.8 million despite more buyers than sellers, indicating large sell orders. Insider 90-day net selling totaled $665,664 vs $585 in buys, net shares -3,405.

Confirmation

Continued insider selling or further institutional net outflow would reinforce the bearish view.

Invalidation Risk

A sudden insider buying spree or a reversal in institutional net value to positive would invalidate this stance.

AI-assisted, sourced from public SEC 13F filings, covering historical data only. Should not be the sole basis for any trade.

Insider Trading (Form 4)

90d confidence

unique buyers

$585

buy value

data as of 2026-07-17

12-Month Buy/Sell Activity

Mar 25

Sep 25

BuySell

Action	Insider	Title	Date	Value
Buy	Murphy Nicole	Head of Pharm Ops and Tech	2026-02-12	$585
Sell	Singhal Priya	Head of Development	2026-02-09	$532K
Sell	Singhal Priya	Head of Development	2026-02-02	$134K
Sell	Singhal Priya	Head of Development	2025-09-02	$69K
Sell	Izzar Rachid	Head of Global Product Strat.	2025-07-08	$300K
Sell	Singhal Priya	Head of Development	2025-05-19	$481K
Buy	DORSA CAROLINE	Director	2025-05-02	$152K
Sell	SHERWIN STEPHEN A	Director	2025-03-07	$1.31M

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Form 144 Pre-Sale Notices

No Form 144 planned sale filings in the last 90 days

Beneficial Ownership (13D/13G)

No Schedule 13D/13G filings for this ticker

Material Events (8-K)

Filings (14d)

Data as of 2026-07-01

2026-07-01

Biogen expects significant charges in the second and third quarters of 2026 related to acquired in-process research and development and milestone payments. The company anticipates a $164 million pre-tax charge in Q2, reducing EPS by $0.95, and a charge between $290 million and $320 million in Q3, reducing EPS by $1.75 to $1.95. These are preliminary estimates and subject to the completion of financial closing procedures.

View Full Filing (SEC EDGAR)

View all Form 8-K filings

FAQ

Who are the top institutional investors holding BIOGEN INC (BIIB)?

Major stakeholders currently include BlackRock, Inc. ($2.9B), Primecap Management Co/ca/ ($2.7B), FMR LLC ($2.3B). Based on the latest 13F filings, there are a total of 1010 tracked investment funds and institutions maintaining positions in BIIB.

What is the overall institutional sentiment toward BIIB recently?

Institutional sentiment appears Bearish (Net Selling). During the most recent reporting quarter, the stock experienced a net outflow of $340.8M, driven by 512 managers accumulating shares while 409 reduced their exposure.

Which institutions have been selling or reducing their BIIB positions?

In the latest period, 301 funds trimmed their holdings, and 108 managers completely exited their positions. The aggregate reported sell value was $11.4B.

Are there any notable investors adding BIIB to their portfolios?

Yes, buying activity remains notable. 112 institutions opened new positions in {ticker}, and 400 existing holders added to their shares. The total reported buy value for the quarter amounted to $13.4B.