BIIBBiogen Inc. Common Stock

CSNasdaq (XNAS)·USD

Identity

Security key: 12528
Ticker: BIIB
Type: CS — Common Stock
Exchange: Nasdaq(XNAS)
Venue group: NASDAQ
Operating MIC: XNAS
Market: stocks
Locale: us
Currency: USD
Listed: 1991-09-17
Round lot: 100
Active: Yes
Last seen in a load: 2026-08-14 20:49
Vendor updated: 2026-08-13 06:09
Ticker root / suffix: BIIB

Detail

Enriched 2026-08-14 20:47

Market cap: $30,861,377,562.26
Shares outstanding (class): 147,753,998
Shares outstanding (weighted): 147,753,998
SIC: 2836 BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
Employees: 7,500
Location: CAMBRIDGE, MA
Homepage: https://www.biogen.com
Description: Biogen is an established biopharmaceutical company focused on treatments for neurodegenerative and rare diseases. Its declining multiple sclerosis franchise is its largest revenue generator and contributed 40% of total revenue in 2025. Biogen also generates significant revenue from its CD20 collaboration agreements with Roche (19% of total in 2025), which includes oncology drugs Rituxan and Gazyva and multiple sclerosis drug Ocrevus. Biogen's newer franchises include Spinraza (spinal muscular atrophy, with partner Ionis), Leqembi (Alzheimer's disease, collabroation revenue from its partner Eisai), Skyclarys (Friedreich's ataxia, Reata), Zurzuvae (postpartum depression, Sage), and Qalsody (amyotrophic lateral sclerosis, Ionis).

Market cap and share counts drift.

Funds holding this security

395 funds · 401 positions · $8.72B reported value, as of 2026-03-31

All holders →

Fund	Ticker	Position value	% of fund	Balance	Match
VANGUARD PRIMECAP FUND VANGUARD CHESTER FUNDS	—	$1.53B	2.12%	8,359,880 NS	FIGI
VANGUARD TOTAL STOCK MARKET INDEX FUND VANGUARD INDEX FUNDS	VTI	$853.39M	0.04%	4,654,936 NS	FIGI
VANGUARD 500 INDEX FUND VANGUARD INDEX FUNDS	VOO	$683.93M	0.05%	3,730,577 NS	FIGI
Fidelity Contrafund Fidelity Contrafund	—	$599.40M	0.38%	3,269,520 NS	FIGI
VANGUARD MID-CAP INDEX FUND VANGUARD INDEX FUNDS	VO	$581.05M	0.29%	3,169,409 NS	FIGI
VANGUARD CAPITAL OPPORTUNITY FUND VANGUARD HORIZON FUNDS	—	$427.63M	1.74%	2,332,567 NS	FIGI
iShares Core S&P 500 ETF iShares Trust	IVV	$346.13M	0.05%	1,888,033 NS	FIGI
N/A —	—	$314.74M	0.05%	1,716,790 NS	FIGI
VANGUARD VALUE INDEX FUND VANGUARD INDEX FUNDS	VTV	$248.89M	0.11%	1,357,618 NS	FIGI
VANGUARD PRIMECAP CORE FUND VANGUARD FENWAY FUNDS	—	$241.43M	1.78%	1,316,936 NS	FIGI
iShares Biotechnology ETF iShares Trust	IBB	$200.02M	2.46%	1,091,046 NS	FIGI
State Street(R) Health Care Select Sector SPDR(… SELECT SECTOR SPDR TRUST	XLV	$195.79M	0.51%	1,067,952 NS	FIGI
VANGUARD MID-CAP VALUE INDEX FUND VANGUARD INDEX FUNDS	VOE	$174.90M	0.50%	954,017 NS	FIGI
VANGUARD INSTITUTIONAL INDEX FUND VANGUARD INSTITUTIONAL INDEX FUNDS	—	$151.68M	0.05%	827,362 NS	FIGI
Disciplined Value Mid Cap Fund John Hancock Funds III	—	$143.29M	0.65%	781,583 NS	FIGI

How positions resolve to the securities master. FIGI_COMPOSITE is exact identifier equality — both sides got the FIGI from Bloomberg. TICKER is a narrow fallback used only where the master row carries no FIGI at all (2,389 rows do not, disproportionately Irish-domiciled US listings like LIN and ACN). Roughly 22% of all positions resolve to the master.

Funds holding this security

Identifiers

master.security_identifier

TICKERBIIB
FIGI_COMPOSITEBBG000C17X76
FIGI_SHARE_CLASSBBG001S67826
CIK0000875045
ISINUS09062X1037
Resolved through OpenFIGI from a holdings ISIN, not supplied by the securities vendor.

Identifiers

Classification

classification.v_security_classification

Asset class: Equity
Sector: Health Care
Industry: Biotechnology
Source: LLMunreviewed
Self-reported confidence: 0.95
Model: deepseek
Rationale: Biogen is a biotechnology company focused on neurological diseases, fitting the healthcare sector and biotechnology industry.

Classifications are unreviewed model output. All 5,771 assignments carry source = LLM and is_reviewed = false. Confidence is the model’s own estimate and is not calibrated — it clustered at 0.90–0.98 across the whole first pass, including rows that later proved wrong. Use it to order a review queue, not as a probability. Two share classes of one issuer can disagree.

Classification

Fund data

Not linked to a fund series.

Either this is not a fund, or it is one the SEC share-class snapshot cannot reach — commodity trusts and notes have no series ID at all.