Biogen (BIIB) Seasonality
Recurring seasonal patterns for BIIB — the calendar windows where Biogen has historically tended to rise or fall, with the win rate (how often it repeated) and average return for each, based on the last 10 years of price history.
BIIB seasonality at a glance
Over the last 10 years, BIIB's strongest seasonal window has been Jul 29 – Aug 8: it ended higher in 9 of 10 years (90% win rate) with an average return of +2.75% across a 10-day hold. On the weak side, BIIB has historically declined between Feb 21 – Mar 23, falling in 9 of 10 years (average -7.80%).
In total, our analysis finds 665 recurring seasonal windows for Biogen — 337 bullish and 328 bearish. The next high-win-rate window, Jul 29 – Aug 8, opens in 2 days. These figures describe historical behaviour only — not a forecast.
BIIB's upcoming & recent seasonal patterns
Holding period:10-day20-day30-dayOrdered by season — windows opening soon first, plus a couple of recently completed high-performers. Holding-period colors help you compare durations at a glance.
| Status | Seasonal window | Hold | Avg return | Win rate | This year |
|---|---|---|---|---|---|
| Completedended 18d ago | Jun 19 – Jul 9 | 20d | +3.55% | 80% | +1.19% |
| Completedended 22d ago | Jun 25 – Jul 5 | 10d | +1.19% | 80% | +7.01% |
| Active20d left | Jul 27 – Aug 16 | 20d | +1.79% | 80% | — |
| Upcomingin 2d | Jul 29 – Aug 8 | 10d | +2.75% | 90% | — |
| Upcomingin 3d | Jul 30 – Aug 9 | 10d | +2.85% | 80% | — |
| Upcomingin 12d | Aug 8 – Aug 18 | 10d | -1.41% | 80% | — |
| Upcomingin 12d | Aug 8 – Sep 7 | 30d | -1.70% | 80% | — |
Win rate = how often the pattern repeated in the same direction. Average return = the mean move across all analysed years. Past performance does not guarantee future results.
Explore BIIB seasonality in full
See the seasonal curve chart, filter by win rate and return, and track upcoming windows — free during beta.
BIIB seasonality FAQ
What has historically been the best month to buy BIIB stock?
Based on the last 10 years of price data, BIIB's strongest seasonal window starts in July: Jul 29 to Aug 8, which ended higher in 9 of 10 years (90% win rate) with an average return of +2.75%. Past seasonal patterns do not guarantee future performance.
What is BIIB's strongest seasonal pattern?
BIIB's highest-win-rate pattern in our data is the Jul 29 – Aug 8 window (10-day hold): up in 9 of the last 10 years with an average move of +2.75%.
When has BIIB historically performed worst?
BIIB's weakest recurring window has been Feb 21 to Mar 23, declining in 9 of 10 years with an average return of -7.80%.
How reliable are BIIB's seasonal patterns?
Each BIIB pattern is scored by its historical win rate — the share of the last 10 years it repeated in the same direction. BIIB currently shows 665 recurring windows (337 bullish, 328 bearish). Seasonality describes historical tendencies only; it is not a prediction, and past performance does not guarantee future results.
What is BIIB stock seasonality?
Stock seasonality is the tendency of a stock to perform in a similar way during the same period each year. By analysing Biogen's price history across many years, SeasonalityX identifies recurring calendar windows — exact start and end dates — where BIIB has repeatedly risen (bullish) or fallen (bearish). Each pattern is scored by its win rate and average return so you can judge how reliable and how strong it has been.
Seasonality is one input among many — it works best alongside your own research and risk management. Learn more in our guide to seasonal analysis and the tutorials.