How popular is soccer? Popular enough to bring financial markets to a halt, it seems. A new paper (pdf) from the European Central Bank finds that during the 2010 World Cup, the number of stock trades plunged an average of 45 percent in countries whose teams were playing at the time. (A goal caused a further 5 percent drop.) “We conclude,” write Michael Ehrmann and David-Jan Jansen, “that stock markets were following developments on the soccer pitch rather than in the trading pit.”

Don’t even think about making that trade. (Lefteris Pitarakis/AP)

What’s more, unlike the drops in activity typically seen during lunch hours, markets in soccer-playing countries diverged significantly from global markets during games, suggesting there really was a marked shift in attention. (And let’s not even get into what happens when a country loses a match — previous research has found that losing a big international soccer match can put a dent in a country’s stock market.)

At the moment, a few Democrats in the U.S. and countries like France and Germany have proposed a financial transaction tax to, in part, tamp down on market volatility. But if that doesn’t pan out, there’s always the option of simply holding more World Cups…

(Hat tip to the WSJ’s Brian Blackstone.)