THE RISE of political polling and subsequent crackdowns on sports gambling drove political betting markets in America underground after the second world war. They remained in the shadows until last month, when a federal court cleared Kalshi, a betting exchange, to offer political bets to Americans. More than $400m has since been wagered on the site. The sums bet globally on other prediction sites reportedly tot up to several billion dollars. How did the speculators fare in America’s election?