The takeaway
Rhythm Pharmaceuticals Inc shows a pronounced seasonal pattern over 9 years of data — strongest in November (+10.7%) and softest in September (−6.2%).
Right now
In July, the stock has risen 50% of years, averaging +24.9%, about +22.8 pts better than the S&P 500.
The full picture
Rhythm Pharmaceuticals Inc's most dependable month has been November, higher in 7 of 9 years; September has been its least reliable, up just 13% of the time.
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Month by month
The stock's clearest edge over the S&P 500 lands in July (+22.8 pts); it has trailed the market most in March (−9.7 pts).
“vs S&P” is Rhythm Pharmaceuticals Inc’s average for a month minus the S&P 500’s average for that same month — isolating Rhythm Pharmaceuticals Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, November has closed higher 60% of the time versus 78% across the last 9 years — the pattern is weakening.
Figures are the typical (median) November return and how often it rose — the last 5 years versus the last 9(the heatmap’s default window). This verdict stays anchored to that 9-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 — November. It has closed higher in 7 of 9 Novembers, a concentration the rest of the calendar can't touch.
Read it with one caveat: the average (+10.7%) runs well ahead of the median (+3.5%), so a handful of outsized years — not steady strength — do much of the lifting. That reliability comes with real swings, mind — even November ranges by 20.8% 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 — November has outpaced the S&P 500 by +8.4 points on average. Few peers keep such company in November — the typical stock clears it just 62% of the time.
Only August comes anywhere near it for reliability. On the other side of the ledger, September has been the soft spot — the weakest of 6 months that average a loss (−6.2%), and the edge isn't year-round — the stock has trailed the S&P 500 in March, May, and January. Its roughest month on record was a −46.9% April in 2022 — a reminder of how hard even a seasonal name can fall.
The pattern has softened of late, November's last five years slipping below its longer-run record.
For a stock this dependable in November, the sharper question is the rest of the year — outside its strong stretch, the calendar gives far less to lean on. With a short 9-year record and returns that swing hard year to year, the signal is best held loosely.
Short answers on the stock's best month (November), its worst (September), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2017 its best month (November, +10.7%) has run well ahead of its worst (September, −6.2%) — the heatmap above shows how steady that gap has been year to year.
November has been the strongest, averaging +10.7% and closing higher in 7 of 9 years since 2017.
It's the weakest, averaging −6.2% — 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.
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