May 8, 2025. As white smoke rose from the Sistine Chapel, signaling the election of a new pope, some are rubbing their hands in delight. Online, thousands had bet on who would succeed Pope Francis, with $40 million wagered in total. Many lost, but some pocketed up to $60,000 for correctly predicting the winner, Robert Francis Prevost, now Leo XIV.

This somewhat cynical business is that of Kalshi and Polymarket. Both American start-ups, these rivals share the same ambition: to surpass sports betting and allow people to bet on world affairs, from presidential elections to the outcome of a war, court decisions and the severity of a natural disaster.

To achieve this, they use a unique method: instead of setting odds like traditional bookmakers, their teams monitor current events and community proposals to launch new markets, taking a commission on each dollar bet. In April 2025 alone, nearly 7,000 markets were opened on Polymarket. Among the most popular were, of course, the new pope, but also the probability of Israel launching a new major military operation in Gaza, the number of posts by Elon Musk on X, the Eurovision winner and the winner of the presidential election in Romania (nearly $200 million in bets).

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