The takeaway
Upstream Bio, Inc. shows a pronounced seasonal pattern over 2 years of data — strongest in October (+42.3%) and softest in January (−33.9%).
Right now
In July, the stock has risen 100% of years, averaging +41.9%, about +39.7 pts better than the S&P 500.
The full picture
Upstream Bio, Inc.'s most dependable month has been October, higher in 2 of 2 years; January has been its least reliable, up just 0% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Win rate % | ||||||||||||
| Median return % | ||||||||||||
| 2025 | ||||||||||||
| 2024 | — | — | — | — | — | — | — | — | — |
Month by month
The stock's clearest edge over the S&P 500 lands in October (+41.3 pts); it has trailed the market most in January (−33.7 pts).
“vs S&P” is Upstream Bio, Inc.’s average for a month minus the S&P 500’s average for that same month — isolating Upstream Bio, Inc.’s own seasonal edge from broad market drift.
Reality check
Not enough recent October history to say whether the pattern still holds.
Figures are the typical (median) October return and how often it rose — the last 2 years versus the last 2(the heatmap’s default window). This verdict stays anchored to that 2-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: October, up in all 2 Octobers while the other eleven tend to blur together.
Its average (+42.3%) and median (+42.3%) land within a hair of each other — the tell of steady, year-after-year gains rather than one outlier doing the work. Crucially, the gain is the stock's own rather than a rising tide's: October has cleared the S&P 500 by +41.3 points above the index. That consistency sets it apart from the field, where the average stock manages October only about 53% of the time.
A few other months pull their weight: April, May, and June have also closed higher more often than not. At the other end of the calendar, January has been the soft spot — the weakest of 5 months that average a loss (−33.9%), and the edge isn't year-round — the stock has trailed the S&P 500 in January, February, and March. Its roughest month on record was a −33.9% January in 2025 — a reminder of how hard even a seasonal name can fall.
The takeaway is less about when to buy than what to expect: October aside, the stock's months offer little reliable tilt. With a short 2-year record, the signal is best held loosely.
Short answers on the stock's best month (October), its worst (January), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2024 its best month (October, +42.3%) has run well ahead of its worst (January, −33.9%) — the heatmap above shows how steady that gap has been year to year.
October has been the strongest, averaging +42.3% and closing higher in all 2 years on record since 2024.
It's the weakest, averaging −33.9% — 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