The takeaway
Mirum Pharmaceuticals Inc shows a pronounced seasonal pattern over 7 years of data — strongest in August (+11.6%) and softest in October (−10.9%).
Right now
In July, the stock has risen 86% of years, averaging +6.7%, about +4.5 pts better than the S&P 500.
The full picture
Mirum Pharmaceuticals Inc's most dependable month has been August, higher in 6 of 7 years; October has been its least reliable, up just 14% 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 December (+28.9 pts); it has trailed the market most in October (−12.0 pts).
“vs S&P” is Mirum Pharmaceuticals Inc’s average for a month minus the S&P 500’s average for that same month — isolating Mirum Pharmaceuticals Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, August has closed higher 100% of the time versus 86% across the last 7 years — the pattern is strengthening.
Figures are the typical (median) August 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
Dependability is the through-line here. August stands out, higher in 6 of 7 Augusts, but it heads a clutch of months that pull the year reliably upward.
A typical August brings +8.1%, a shade under the +11.6% average. That reliability comes with real swings, mind — even August ranges by 13.9% 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: August has cleared the S&P 500 by +11.3 points above the index. That consistency sets it apart from the field, where the average stock manages August only about 52% of the time.
The strength clusters rather than stands alone — June–August forms a firm stretch that carries much of the year. On the other side of the ledger, October has been the soft spot — the weakest of 3 months that average a loss (−10.9%), and the edge isn't year-round — the stock has trailed the S&P 500 in October, May, and March. Its roughest month on record was a −33.9% January in 2020 — a reminder of how hard even a seasonal name can fall.
August has now closed higher 6 years running. If anything it has sharpened recently — the last five Augusts run ahead of the earlier years.
The takeaway is less about when to buy than what to expect: August 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 (August), its worst (October), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2019 its best month (August, +11.6%) has run well ahead of its worst (October, −10.9%) — the heatmap above shows how steady that gap has been year to year.
August has been the strongest, averaging +11.6% and closing higher in 6 of 7 years since 2019.
It's the weakest, averaging −10.9% — 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