Observatory · observe first
Biogen
BIIB · United States · Biotechnology · matched S&P 500 member. Follow its market-weight contribution.
Historical time machine
Historical observation
20182026
Universe weight
0.040%
12M weight contribution
-0.032 pp
3M weight contribution
-0.003 pp
12M price return
-35.4%
Share of matched S&P 500 members
Monthly observations through Aug 2025
Company price index
A separate dimension from market allocation
Historical observations
Most recent 24 observations at or before the selected month
| Month | Market cap | Universe weight | 12M weight change | 12M return | Above 6M weight average |
|---|---|---|---|---|---|
| Aug 2025 | $19.4bn | 0.040% | -0.032 pp | -35.4% | No |
| Jul 2025 | $18.8bn | 0.040% | -0.016 pp | -40.0% | No |
| Jun 2025 | $18.4bn | 0.040% | -0.024 pp | -45.8% | No |
| May 2025 | $19.0bn | 0.043% | -0.020 pp | -42.3% | No |
| Apr 2025 | $17.7bn | 0.043% | -0.048 pp | -43.6% | No |
| Mar 2025 | $20.0bn | 0.048% | -0.039 pp | -36.5% | No |
| Feb 2025 | $20.6bn | 0.046% | -0.044 pp | -35.3% | No |
| Jan 2025 | $21.0bn | 0.047% | -0.060 pp | -41.6% | No |
| Dec 2024 | $22.3bn | 0.051% | -0.061 pp | -40.9% | No |
| Nov 2024 | $23.4bn | 0.052% | -0.054 pp | -31.4% | No |
| Oct 2024 | $25.4bn | 0.060% | -0.057 pp | -26.7% | No |
| Sep 2024 | $28.2bn | 0.066% | -0.059 pp | -24.6% | No |
| Aug 2024 | $29.8bn | 0.072% | -0.051 pp | -23.4% | Yes |
| Jul 2024 | $31.0bn | 0.056% | -0.030 pp | -21.1% | No |
| Jun 2024 | $33.8bn | 0.063% | -0.032 pp | -18.6% | No |
| May 2024 | $32.8bn | 0.063% | -0.043 pp | -24.1% | No |
| Apr 2024 | $31.3bn | 0.091% | -0.058 pp | -29.4% | No |
| Mar 2024 | $31.3bn | 0.087% | -0.050 pp | -22.4% | No |
| Feb 2024 | $31.5bn | 0.090% | -0.047 pp | -19.6% | No |
| Jan 2024 | $35.7bn | 0.106% | -0.037 pp | -15.2% | No |
| Dec 2023 | $37.5bn | 0.112% | -0.032 pp | -6.6% | Yes |
| Nov 2023 | $33.9bn | 0.106% | -0.043 pp | -23.3% | No |
| Oct 2023 | $34.4bn | 0.117% | -0.028 pp | -16.2% | Yes |
| Sep 2023 | $37.2bn | 0.124% | -0.028 pp | -3.7% | Yes |
Its weight is estimated market cap divided by the total estimated market cap of matched S&P 500 members for the month. This is not an official float-adjusted S&P index weight.