Shares Outstanding for Biogen (BIIB)
According to Biogen's latest reported financial statements, the company's latest reported diluted shares outstanding is 146.70M. Diluted weighted-average shares outstanding is the share count used to compute per-share metrics like EPS. Buybacks lower it; new issuance, stock-based compensation, and convertible securities raise it. Multiply by the stock price for market capitalization.
Headline figure above is from the reporting period ending (reported ). Chart and table below cover the full reported history back to .
BIIB
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Latest period
146.70M
YoY change
+0.5%
5Y CAGR
-1.9%
Peak year (1998)
945.52M
Latest annual
146.70M
Shares Outstanding history chart for Biogen (BIIB) from 1985 to 2025
Shares Outstanding history table for Biogen (BIIB) from 1985 to 2025
| Fiscal year | Period ended | Reported | Shares Outstanding | YoY |
|---|---|---|---|---|
| 2025 | 146.70M | +0.5% | ||
| 2024 | 145.90M | +0.2% | ||
| 2023 | 145.60M | -0.3% | ||
| 2022 | 146.00M | -2.4% | ||
| 2021 | 149.60M | -7.3% | ||
| 2020 | 161.30M | -13.9% | ||
| 2019 | 187.40M | -8.7% | ||
| 2018 | 205.30M | -3.6% | ||
| 2017 | 213.00M | -2.7% | ||
| 2016 | 218.80M | -5.4% | ||
| 2015 | 231.20M | -2.5% | ||
| 2014 | 237.18M | -0.5% | ||
| 2013 | 238.31M | -0.6% | ||
| 2012 | 239.74M | -2.2% | ||
| 2011 | 245.03M | -3.9% | ||
| 2010 | 254.87M | -12.0% | ||
| 2009 | 289.48M | -1.9% | ||
| 2008 | 294.98M | -7.9% | ||
| 2007 | 320.17M | -7.3% | ||
| 2006 | 345.28M | -0.3% | ||
| 2005 | 346.16M | +0.8% | ||
| 2004 | 343.48M | +2.9% | ||
| 2003 | 333.70M | -16.3% | ||
| 2002 | 398.75M | 0.0% | ||
| 2001 | 398.75M | -14.0% | ||
| 2000 | 463.81M | -2.0% | ||
| 1999 | 473.36M | -49.9% | ||
| 1998 | 945.52M | +2.0% | ||
| 1997 | 926.67M | +0.4% | ||
| 1996 | 922.86M | +30.9% | ||
| 1995 | 705.00M | -13.6% | ||
| 1994 | 816.00M | +0.7% | ||
| 1993 | 810.00M | -4.8% | ||
| 1992 | 851.11M | +26.1% | ||
| 1991 | 675.00M | +25.0% | ||
| 1990 | 540.00M | +38.5% | ||
| 1989 | 390.00M | +62.5% | ||
| 1988 | 240.00M | -54.0% | ||
| 1987 | 521.54M | +11.0% | ||
| 1986 | 470.00M | +6.6% | ||
| 1985 | 440.77M | — |
Shares Outstanding values are taken from Biogen's reported income statements (10-Q quarterly and 10-K annual filings with the U.S. Securities and Exchange Commission). Each row shows the period end date and the date the filing was reported; YoY compares each figure to the same period one year earlier. Amounts are in USD as filed.
Analysis
2025's annual diluted shares outstanding for Biogen (BIIB) came in at 146.70M – edged up 0.5% year-over-year.
Biogen diluted shares outstanding compound annual growth for the 2020–2025 (5 years) window is -1.9%, sustaining 2 straight years of year-over-year growth.
Biogen diluted shares outstanding plunged from 945.52M in 1998 to 146.70M in 2025, a 84.5% drawdown.
The highest annual diluted shares outstanding of 945.52M was reported in 1998. The lowest in the available history was 145.60M in 2023.
Within Healthcare, Biogen (BIIB) ranks 9th among 8 peers we track. The peer median for diluted shares outstanding is 1.34B.
Biogen Shares Outstanding by Year
Biogen Shares Outstanding 2025: 146.70M
Biogen diluted shares outstanding in 2025 was 146.70M, edged up 0.5% from 2024.
Biogen Shares Outstanding 2024: 145.90M
Biogen diluted shares outstanding in 2024 was 145.90M, edged up 0.2% from 2023.
Biogen Shares Outstanding 2023: 145.60M
Biogen diluted shares outstanding in 2023 was 145.60M, edged down 0.3% below 2022. This figure represents the lowest annual value in the available history.
Biogen Shares Outstanding 2022: 146.00M
Biogen diluted shares outstanding in 2022 was 146.00M, edged down 2.4% below 2021.
Biogen Shares Outstanding 2021: 149.60M
Biogen diluted shares outstanding in 2021 was 149.60M.
See more financial history for Biogen (BIIB).
Sector peers — Shares Outstanding
Companies in the same sector as Biogen, ranked by their latest diluted shares outstanding.
| Company | Shares Outstanding | Sector |
|---|---|---|
| Novo Nordisk A/S (NVO) | 4.45B | Healthcare |
| Merck & Co., Inc. (MRK) | 2.51B | Healthcare |
| Johnson & Johnson (JNJ) | 2.43B | Healthcare |
| AbbVie Inc. (ABBV) | 1.77B | Healthcare |
| UnitedHealth Group Incorporated (UNH) | 910.00M | Healthcare |
| Eli Lilly and Company (LLY) | 898.00M | Healthcare |
| AstraZeneca PLC (AZN) | 781.00M | Healthcare |
| Amgen Inc. (AMGN) | 542.00M | Healthcare |
Frequently asked questions
What is Biogen's diluted shares outstanding?
- Latest reported diluted shares outstanding for Biogen (BIIB) is 146.70M (period ending December 31, 2025).
How has Biogen diluted shares outstanding changed year-over-year?
- Biogen (BIIB) diluted shares outstanding changed +0.5% year-over-year on the latest annual filing.
What is the long-term growth rate of Biogen diluted shares outstanding?
- Biogen (BIIB) diluted shares outstanding compound annual growth rate is -1.9% over the most recent 5 years available.
When did Biogen diluted shares outstanding hit its highest annual value?
- Biogen diluted shares outstanding reached its highest annual value of 945.52M in 1998.
What was Biogen diluted shares outstanding in 2024?
- Biogen (BIIB) diluted shares outstanding in 2024 was 145.90M.
What was Biogen diluted shares outstanding in 2025?
- Biogen (BIIB) diluted shares outstanding in 2025 was 146.70M.
Metrics overview
Pick a metric for charts, filings, and peers — each row shows the latest TTM or annual value with year-over-year change.
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