The takeaway
Ideaya Biosciences Inc shows a pronounced seasonal pattern over 7 years of data — strongest in September (+11.4%) and softest in March (−12.4%).
Right now
In July, the stock has risen 57% of years, averaging +2.5% — essentially in line with the S&P 500.
The full picture
Ideaya Biosciences Inc's most dependable month has been September, higher in 5 of 7 years; March has been its least reliable, up just 17% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
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| 2019 | — | — | — | — |
Month by month
The stock's clearest edge over the S&P 500 lands in May (+14.5 pts); it has trailed the market most in March (−13.4 pts).
“vs S&P” is Ideaya Biosciences Inc’s average for a month minus the S&P 500’s average for that same month — isolating Ideaya Biosciences Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, September has closed higher 60% of the time versus 71% across the last 7 years — the pattern is weakening.
Figures are the typical (median) September return and how often it rose — the last 5 years versus the last 7(the heatmap’s default window). This verdict stays anchored to that 7-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: September, up in 5 of 7 Septembers while the other eleven tend to blur together.
The headline flatters a touch — its +11.4% average sits well above the +4.1% a typical year delivers, the work of a few big Septembers. That reliability comes with real swings, mind — even September ranges by 23.3% from year to year, so any single year can land far from the average. Crucially, the gain is the stock's own rather than a rising tide's: September has cleared the S&P 500 by +11.5 points above the index. It bucks the broad tape, besides: September lifts just 39% of stocks across the market.
A few other months pull their weight: November and December have also closed higher more often than not. The weaker half of the year is plainer: March has been the soft spot — the weakest of 4 months that average a loss (−12.4%), and the edge isn't year-round — the stock has trailed the S&P 500 in March, February, and October. Its roughest month on record was a −40.8% March in 2020 — a reminder of how hard even a seasonal name can fall.
The pattern has softened of late, September's last five years slipping below its longer-run record.
The takeaway is less about when to buy than what to expect: September aside, the stock's months offer little reliable tilt. With a short 7-year record and returns that swing hard year to year, the signal is best held loosely.
Short answers on the stock's best month (September), its worst (March), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2019 its best month (September, +11.4%) has run well ahead of its worst (March, −12.4%) — the heatmap above shows how steady that gap has been year to year.
September has been the strongest, averaging +11.4% and closing higher in 5 of 7 years since 2019.
It's the weakest, averaging −12.4% — 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