The takeaway
Jazz Pharmaceuticals PLC shows a slight seasonal lean over 10 years of data — strongest in March (+0.8%) and softest in May (−1.4%).
Right now
In July, the stock has risen 40% of years, averaging +0.7%, roughly 1.4 pts behind the S&P 500.
The full picture
Jazz Pharmaceuticals PLC's most dependable month has been March, higher in 7 of 10 years; May has been its least reliable, up just 30% of the time.
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Month by month
The stock's clearest edge over the S&P 500 lands in January (+0.9 pts); it has trailed the market most in October (−2.2 pts).
“vs S&P” is Jazz Pharmaceuticals PLC’s average for a month minus the S&P 500’s average for that same month — isolating Jazz Pharmaceuticals PLC’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, March has closed higher 60% of the time versus 70% across the last 10 years — the pattern is weakening.
Figures are the typical (median) March 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
Strip the year back and a single month does the heavy lifting: March, up in 7 of 10 Marches while the other eleven tend to blur together.
Its average (+0.8%) and median (+3.5%) 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 March ranges by 9.5% from year to year, so any single year can land far from the average. Set against the S&P 500, mind, March is close to a wash — the gain mirrors the market more than it beats it. That consistency sets it apart from the field, where the average stock manages March only about 56% of the time.
A few other months pull their weight: January, June, and December have also closed higher more often than not. On the other side of the ledger, May has been the soft spot — the weakest of 4 months that average a loss (−1.4%), and the edge isn't year-round — the stock has trailed the S&P 500 in October, May, and September. Its roughest month on record was a −22.8% August in 2021 — a reminder of how hard even a seasonal name can fall.
The pattern has softened of late, March's last five years slipping below its longer-run record.
The takeaway is less about when to buy than what to expect: March aside, the stock's months offer little reliable tilt.
Short answers on the stock's best month (March), its worst (May), and whether it really trades seasonally.
Only mildly. The stock's months are fairly even — March is the firmest (+0.8%) and May the softest (−1.4%), a narrow spread that points to weak seasonality rather than a strong calendar effect.
March has been the strongest, averaging +0.8% and closing higher in 7 of 10 years since 2016.
It's the weakest, averaging −1.4% — 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