The takeaway
Biomarin Pharmaceutical Inc shows a pronounced seasonal pattern over 10 years of data — strongest in November (+6.0%) and softest in October (−3.5%).
Right now
In July, the stock has risen 60% of years, averaging +1.6%, roughly 0.5 pts behind the S&P 500.
The full picture
Biomarin Pharmaceutical Inc's most dependable month has been November, higher in 8 of 10 years; October has been its least reliable, up just 20% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Win rate % | ||||||||||||
| Median return % | ||||||||||||
| 2025 | ||||||||||||
| 2024 | ||||||||||||
| 2023 | ||||||||||||
| 2022 | ||||||||||||
| 2021 | ||||||||||||
| 2020 | ||||||||||||
| 2019 | ||||||||||||
| 2018 | ||||||||||||
| 2017 | ||||||||||||
| 2016 |
Month by month
The stock's clearest edge over the S&P 500 lands in November (+3.7 pts); it has trailed the market most in September (−5.7 pts).
“vs S&P” is Biomarin Pharmaceutical Inc’s average for a month minus the S&P 500’s average for that same month — isolating Biomarin Pharmaceutical Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, November has closed higher 80% of the time versus 80% across the last 10 years — the pattern is holding.
Figures are the typical (median) November return and how often it rose — the last 5 years versus the last 10(the heatmap’s default window). This verdict stays anchored to that 10-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
Strip the year back and a single month does the heavy lifting: November, up in 8 of 10 Novembers while the other eleven tend to blur together.
Its average (+6.0%) and median (+5.9%) land within a hair of each other — the tell of steady, year-after-year gains rather than one outlier doing the work. It is among its calmest months, too, its returns swinging least from year to year (a 4.9% spread), and even its worst November in 10 years lost only 1.5% — the gentlest downside anywhere on its calendar. Crucially, the gain is the stock's own rather than a rising tide's: November has cleared the S&P 500 by +3.7 points above the index. That consistency sets it apart from the field, where the average stock manages November only about 62% of the time.
A few other months pull their weight: April, June, and July have also closed higher more often than not. The weaker half of the year is plainer: October has been the soft spot — the weakest of 7 months that average a loss (−3.5%), and the edge isn't year-round — the stock has trailed the S&P 500 in September, October, and March. Its roughest month on record was a −36.1% August in 2020 — a reminder of how hard even a seasonal name can fall.
Reassuringly, the tendency has held its shape: the recent five years still track the years behind them.
The takeaway is less about when to buy than what to expect: November aside, the stock's months offer little reliable tilt.
Short answers on the stock's best month (November), its worst (October), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2016 its best month (November, +6.0%) has run well ahead of its worst (October, −3.5%) — the heatmap above shows how steady that gap has been year to year.
November has been the strongest, averaging +6.0% and closing higher in 8 of 10 years since 2016.
It's the weakest, averaging −3.5% — historically a soft spot, though it still varies from year to year.
Explore
These names have the strongest July track records on record — a starting point for comparison.
Before you trade