Company · Ownership research

BIOGEN INC. BIIB

CIK 0000875045 · CUSIP 09062X103

Insider tradingInitial holdingsInstitutional holders

Quarter-end disclosures, not live holdings.

4 CUSIPs are reported under this ticker. This page covers the one most managers report; the others are not merged in.
This page lists the top 20 of 910 rows by value; the complete set is available through the API.

Top 20 institutions

Weight means this stock's share of the manager's own portfolio.

By reported value
#ManagerValueManager weightChange vs priorSource

Showing 20 / 910 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions
910
Cancelled or null records excluded
Disclosed shares
131,320,539
Not deduplicated across managers
Disclosed value
$18.47B
Not market cap or free float

Reporting institutions by quarter

Counts also change with data coverage and reporting entities; they do not measure net buying. Distinct managers with a live stock row in this CUSIP; totals may include overlapping filings and are not a share of the company.

BIOGEN INC. · Q3 2025

Explore all 910 reporting institutions.

This page includes 20 of 910 reporting institutions. Sign in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and get the complete set through the Akkru API.

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The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. This page lists 20 of 910 reporting institutions; totals use the complete disclosed data.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP.

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{"cusip":"09062X103","quarter":"2025Q3","type":"positions","page_size":100}

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Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.