Luck of the Irish? Analysis of last 25 years show stocks turn green on St Patrick’s Day

Investors may have the luck of the Irish on their side this St Patrick’s Day. New analysis by trading and investing platform IG shows that 17 March has historically delivered stronger-than-average returns for equities.

Analysis of market data since 2000 shows that the S&P 500 has delivered an average gain of around 1% on St Patrick’s Day itself, a massive 33-fold increase on the average daily gain of 0.03%. The rally often follows a softer period for markets, with the five trading sessions leading up to 17 March posting an average return of -0.08%.

The pattern is also visible in the UK. Over the same period, the FTSE 100 has averaged a gain of 0.35% on St Patrick’s Day - compared to an average daily gain of 0.02% - despite falling -0.74% on average in the week beforehand.

While the positive pattern may appear coincidental, markets have long shown seasonal quirks around holidays - a so-called “holiday effect”- where stock returns around festive periods tend to outperform typical trading days. This may partly reflect improved investor sentiment and optimism on these days, which can encourage risk-taking and boost equities. Lower trading volumes during holiday periods may also amplify moves, meaning even modest buying can push markets higher than usual.

In total, markets have been open on 18 St Patrick’s Days since the year 2000, giving investors nearly two decades of market data to analyse.

Chris Beauchamp, Chief Market Analyst at IG, said: “Investors often talk about the ‘luck of the Irish’, and the data suggests markets like to share in the celebration. While the days leading up to St Patrick’s Day have tended to be a little gloomy, the 17th itself has historically brought a welcome splash of green to trading screens.

“Of course, investors shouldn’t rely on calendar effects alone when making decisions. But these patterns show how sentiment can shift quickly - and occasionally markets seem to find a bit of luck right when investors might need it.”

For long-term investors, the findings reinforce a broader point: short-term volatility is common, but markets have historically shown a strong ability to recover quickly, even within the space of a few trading sessions.

Table: Average market performance around St Patrick’s Day (since 2000)

Source: Bloomberg. Data since 2000. Markets open on 18 St Patrick’s Days during the period. Past performance does not guarantee future results.

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About IG Group

IG Group (LSEG:IGG) provides online trading platforms and educational resources to empower ambitious clients around the globe. Headquartered in the UK, IG Group is a FTSE 250 company that offers clients access to c.19,000 financial markets worldwide.

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