The takeaway
Vistra Corp. shows a pronounced seasonal pattern over 10 years of data — strongest in September (+7.0%) and softest in February (−2.8%).
Right now
In July, the stock has risen 44% of years, averaging +0.6%, roughly 1.5 pts behind the S&P 500.
The full picture
Vistra Corp.'s most dependable month has been September, higher in 7 of 9 years; February has been its least reliable, up just 33% of the time.
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| 2016 | — | — | — | — | — | — | — | — | — |
Month by month
The stock's clearest edge over the S&P 500 lands in September (+7.1 pts); it has trailed the market most in February (−2.6 pts).
“vs S&P” is Vistra Corp.’s average for a month minus the S&P 500’s average for that same month — isolating Vistra Corp.’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, September has closed higher 60% of the time versus 78% across the last 10 years — the pattern is weakening.
Figures are the typical (median) September 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
Dependability is the through-line here. September stands out, higher in 7 of 9 Septembers, but it heads a clutch of months that pull the year reliably upward.
Its average (+7.0%) and median (+5.0%) land within a hair of each other — the tell of steady, year-after-year gains rather than one outlier doing the work. That reliability comes with real swings, mind — even September ranges by 19.2% 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 +7.1 points above the index. It bucks the broad tape, besides: September lifts just 39% of stocks across the market.
The strength clusters rather than stands alone — August–October forms a firm stretch that carries much of the year. On the other side of the ledger, February has been the soft spot — the only month to average an outright loss (−2.8%), and the edge isn't year-round — the stock has trailed the S&P 500 in February and July. Its roughest month on record was a −20.7% February in 2025 — 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.
Short answers on the stock's best month (September), its worst (February), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2016 its best month (September, +7.0%) has run well ahead of its worst (February, −2.8%) — the heatmap above shows how steady that gap has been year to year.
September has been the strongest, averaging +7.0% and closing higher in 7 of 9 years since 2016.
It's the weakest, averaging −2.8% — 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