The takeaway
Amprius Technologies Inc. shows a pronounced seasonal pattern over 4 years of data — strongest in September (+12.2%) and softest in February (−12.6%).
Right now
In July, the stock has risen 67% of years, averaging +27.2%, about +25.1 pts better than the S&P 500.
The full picture
Amprius Technologies Inc.'s most dependable month has been September, higher in 3 of 4 years; February has been its least reliable, up just 33% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Win rate % | ||||||||||||
| Median return % | ||||||||||||
| 2025 | ||||||||||||
| 2024 | ||||||||||||
| 2023 | ||||||||||||
| 2022 | — | — | — | — | — | — | — | — |
Month by month
The stock's clearest edge over the S&P 500 lands in July (+25.1 pts); it has trailed the market most in April (−12.9 pts).
“vs S&P” is Amprius Technologies Inc.’s average for a month minus the S&P 500’s average for that same month — isolating Amprius Technologies Inc.’s own seasonal edge from broad market drift.
Reality check
Over the last 4 years, September has closed higher 75% of the time versus 75% across the last 4 years — the pattern is holding.
Figures are the typical (median) September return and how often it rose — the last 4 years versus the last 4(the heatmap’s default window). This verdict stays anchored to that 4-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
The seasonal story is really one month's story — September. It has closed higher in 3 of 4 Septembers, a concentration the rest of the calendar can't touch.
Read it with one caveat: the average (+12.2%) runs well ahead of the median (+6.5%), so a handful of outsized years — not steady strength — do much of the lifting. That reliability comes with real swings, mind — even September ranges by 19.6% from year to year, so any single year can land far from the average. Better still, that strength is the stock's own and not just a buoyant market — September has outpaced the S&P 500 by +12.4 points on average. It is the more striking for the company it keeps — September is a losing month for most of the market, where barely 39% of names gain ground.
It doesn't stand entirely alone — January, March, and July have leaned firm as well, if less emphatically. On the other side of the ledger, February has been the soft spot — the weakest of 5 months that average a loss (−12.6%), and the edge isn't year-round — the stock has trailed the S&P 500 in April, February, and August. Its roughest month on record was a −38.0% October in 2023 — a reminder of how hard even a seasonal name can fall.
For a stock this dependable in September, the sharper question is the rest of the year — outside its strong stretch, the calendar gives far less to lean on. With a short 4-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 (February), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2022 its best month (September, +12.2%) has run well ahead of its worst (February, −12.6%) — the heatmap above shows how steady that gap has been year to year.
September has been the strongest, averaging +12.2% and closing higher in 3 of 4 years since 2022.
It's the weakest, averaging −12.6% — 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