’Tis the season for holly, cards — and predictions. As the tumultuous year that is 2025 draws to a close, a well-worn ritual is under way: pundits are issuing solemn forecasts for 2026 on inflation, geopolitics, stock markets and more. 

Now, however, there is a new twist: amateurs are jumping into this game too. One particularly striking trend in America is an explosion in the online prediction markets, including sites such as Kalshi and Polymarket, that let anyone place bets on the future.

Indeed over the past two years, activity on these platforms has risen 130-fold, from less than $100mn a month in early 2024 to more than $13bn. Yes, really. And this seems set to continue: the Citizens Financial Group predicts a fivefold increase in prediction companies’ revenues between now and 2030.