How much did BIIB move each index today?
S&P 500: BIIB moved +0.27% and contributed +0.0 points of the index's +0.8-point move, ranking #247 of 503 members by contribution to the move.
XLV: BIIB moved +0.27% and contributed +0.00 points against the index's −1.71-point move, offsetting 0% of it, ranking #40 of 59 members by contribution to the move.
XBI: BIIB moved +0.27% and contributed +0.00 points against the index's −0.72-point move, offsetting 1% of it, ranking #106 of 147 members by contribution to the move.
BIIB closed the 2026-08-25 session at 220.77; that day's move sits in the 74th percentile of its own past year. The stock is 0.4% below its 52-week closing high and +25.4% for the year so far.
BIIB in the S&P 500 beyond today
| window | BIIB return | points contributed | index move | rank |
|---|---|---|---|---|
| 1 week | +3.87% | +0.1 pts | −14.5 pts | #376 of 503 |
| 1 month | +10.31% | +0.3 pts | +264.1 pts | #144 of 503 |
| quarter to date | +2.18% | +0.1 pts | +177.9 pts | #258 of 503 |
| year to date | +25.44% | +0.7 pts | +831.8 pts | #165 of 503 |
Who moved with and against BIIB today?
On BIIB's side of the S&P 500 tape: AAPL (+6.1 pts), MSFT (+3.8 pts), META (+1.5 pts). Pulling the other way: NVDA (−8.6 pts), LLY (−4.1 pts), GOOGL (−3.4 pts).
Every member's contribution, top to bottom, is on the index dashboards; the day's story is in the market-close note. Machine-readable figures for this stock: /api/stock/BIIB, free to cite with attribution.