Latest period
149M
YoY change
+0.5%
5Y CAGR
-1.9%
Peak year (FY1998)
946M
Latest annual
147M
Shares Outstanding history chart for Biogen (BIIB) from 2016 to 2025
Latest: 147M
Shares Outstanding growth chart for Biogen (BIIB) from 2016 to 2025
Latest: +0.5%
Shares Outstanding history table for Biogen (BIIB) from 1985 to 2025
| FY2025 | 147M | +0.5% | +800K | ||
| FY2024 | 146M | +0.2% | +300K | ||
| FY2023 | 146M | -0.3% | -400K | ||
| FY2022 | 146M | -2.4% | -3.6M | ||
| FY2021 | 150M | -7.3% | -11.7M | ||
| FY2020 | 161M | -13.9% | -26.1M | ||
| FY2019 | 187M | -8.7% | -17.9M | ||
| FY2018 | 205M | -3.6% | -7.7M | ||
| FY2017 | 213M | -2.7% | -5.8M | ||
| FY2016 | 219M | -5.4% | -12.4M | ||
| FY2015 | 231M | -2.5% | -5.98M | ||
| FY2014 | 237M | -0.5% | -1.13M | ||
| FY2013 | 238M | -0.6% | -1.43M | ||
| FY2012 | 240M | -2.2% | -5.29M | ||
| FY2011 | 245M | -3.9% | -9.83M | ||
| FY2010 | 255M | -12.0% | -34.6M | ||
| FY2009 | 289M | -1.9% | -5.51M | ||
| FY2008 | 295M | -7.9% | -25.2M | ||
| FY2007 | 320M | -7.3% | -25.1M | ||
| FY2006 | 345M | -0.3% | -882K | ||
| FY2005 | 346M | +0.8% | +2.69M | ||
| FY2004 | 343M | +2.9% | +9.78M | ||
| FY2003 | 334M | -16.3% | -65.1M | ||
| FY2002 | 399M | 0.0% | 0 | ||
| FY2001 | 399M | -14.0% | -65.1M | ||
| FY2000 | 464M | -2.0% | -9.56M | ||
| FY1999 | 473M | -49.9% | -472M | ||
| FY1998 | 946M | +2.0% | +18.9M | ||
| FY1997 | 927M | +0.4% | +3.81M | ||
| FY1996 | 923M | +30.9% | +218M | ||
| FY1995 | 705M | -13.6% | -111M | ||
| FY1994 | 816M | +0.7% | +6M | ||
| FY1993 | 810M | -4.8% | -41.1M | ||
| FY1992 | 851M | +26.1% | +176M | ||
| FY1991 | 675M | +25.0% | +135M | ||
| FY1990 | 540M | +38.5% | +150M | ||
| FY1989 | 390M | +62.5% | +150M | ||
| FY1988 | 240M | -54.0% | -282M | ||
| FY1987 | 522M | +11.0% | +51.5M | ||
| FY1986 | 470M | +6.6% | +29.2M | ||
| FY1985 | 441M | — | — |
- FY2025147M+0.5%
- FY2024146M+0.2%
- FY2023146M-0.3%
- FY2022146M-2.4%
- FY2021150M-7.3%
- FY2020161M-13.9%
- FY2019187M-8.7%
- FY2018205M-3.6%
- FY2017213M-2.7%
- FY2016219M-5.4%
- FY2015231M-2.5%
- FY2014237M-0.5%
- FY2013238M-0.6%
- FY2012240M-2.2%
- FY2011245M-3.9%
- FY2010255M-12.0%
- FY2009289M-1.9%
- FY2008295M-7.9%
- FY2007320M-7.3%
- FY2006345M-0.3%
- FY2005346M+0.8%
- FY2004343M+2.9%
- FY2003334M-16.3%
- FY2002399M0.0%
- FY2001399M-14.0%
- FY2000464M-2.0%
- FY1999473M-49.9%
- FY1998946M+2.0%
- FY1997927M+0.4%
- FY1996923M+30.9%
- FY1995705M-13.6%
- FY1994816M+0.7%
- FY1993810M-4.8%
- FY1992851M+26.1%
- FY1991675M+25.0%
- FY1990540M+38.5%
- FY1989390M+62.5%
- FY1988240M-54.0%
- FY1987522M+11.0%
- FY1986470M+6.6%
- FY1985441M—
Shares Outstanding values are taken from Biogen's reported income statements (quarterly 10-Q and annual 10-K filings with the U.S. Securities and Exchange Commission). Each row shows the period end date and the filing date. YoY compares each figure to the same period one year earlier. Amounts are in USD as filed.
About Shares Outstanding at Biogen (BIIB)
According to Biogen's latest reported financial statements, the company's latest reported diluted shares outstanding is 149M. 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 .
2025's annual diluted shares outstanding for Biogen (BIIB) came in at 147M – 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 946M in 1998 to 147M in 2025, a 84.5% drawdown.
The highest annual diluted shares outstanding of 946M was reported in 1998. The lowest in the available history was 146M in 2023.
Biogen Shares Outstanding by Year
Biogen Shares Outstanding 2025: 147M
Biogen posted diluted shares outstanding of 147M in 2025, edged up 0.5% from 2024.
Biogen Shares Outstanding 2024: 146M
In 2024, Biogen reported diluted shares outstanding of 146M, edged up 0.2% from 2023.
Biogen Shares Outstanding 2023: 146M
Biogen diluted shares outstanding in 2023 was 146M, edged down 0.3% below 2022. This figure represents the lowest annual value in the available history.
Biogen Shares Outstanding 2022: 146M
2022's diluted shares outstanding for Biogen came in at 146M, edged down 2.4% below 2021.
Biogen Shares Outstanding 2021: 150M
Biogen diluted shares outstanding in 2021 was 150M.
See more financial history for Biogen (BIIB).
Sector peers by Shares Outstanding
Healthcare peers of Biogen (BIIB), ranked by their latest diluted shares outstanding
Frequently asked questions
Biogen (BIIB) Key Financials
Charts, filings, and peer comparison for every metric
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Deep-dives across the income statement, cash flow, capital return, and valuation
How this company returns cash to shareholders — buybacks, dividends, and stock splits.