The takeaway
Korro Bio, Inc. shows a pronounced seasonal pattern over 7 years of data — strongest in July (+20.5%) and softest in February (−29.4%).
Right now
In July, the stock has risen 67% of years, averaging +20.5%, about +18.4 pts better than the S&P 500.
The full picture
Korro Bio, Inc.'s most dependable month has been July, higher in 4 of 6 years; February 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 November (+24.4 pts); it has trailed the market most in February (−29.1 pts).
“vs S&P” is Korro Bio, Inc.’s average for a month minus the S&P 500’s average for that same month — isolating Korro Bio, Inc.’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, July has closed higher 80% of the time versus 67% across the last 7 years — the pattern is strengthening.
Figures are the typical (median) July 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
There's a real but measured seasonal tilt here, toward July — the firmest corner of the calendar, higher in 4 of 6 Julys.
The strength looks broad-based rather than freakish: its average (+20.5%) and median (+27.1%) sit close together, so no single blow-out year is flattering the figure. Few months are steadier: July's returns vary by just 22.2% year to year, and even its worst July in 7 years lost only 9.9% — the gentlest downside anywhere on its calendar. Better still, that strength is the stock's own and not just a buoyant market — July has outpaced the S&P 500 by +18.4 points on average. Some of that is a strong month market-wide, mind — July rises for about 61% of stocks — so the tendency is real if not unique.
It doesn't stand entirely alone — January and June have leaned firm as well, if less emphatically. At the other end of the calendar, February has been the soft spot — the weakest of 4 months that average a loss (−29.4%), and the edge isn't year-round — the stock has trailed the S&P 500 in February, March, and May. Its roughest month on record was a −84.5% November in 2025 — a reminder of how hard even a seasonal name can fall.
If anything it has sharpened recently — the last five Julys run ahead of the earlier years.
Treat it as a tendency rather than a rule — seasonality describes the past, not a promise. 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 (July), its worst (February), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2019 its best month (July, +20.5%) has run well ahead of its worst (February, −29.4%) — the heatmap above shows how steady that gap has been year to year.
July has been the strongest, averaging +20.5% and closing higher in 4 of 6 years since 2019.
It's the weakest, averaging −29.4% — 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