Online bettors spent over $40 million gambling on the identity of the next pope—one winner made $52,000 on a longshot

Many people tried to predict who the new pope would be, even putting money on it. Few expected him to be an American from Chicago.

Bettors poured more than $40 million into the most recent papal conclave, on just two prediction market platforms: over $30 million on Polymarket, according to its website, and over $10.6 million on Kalshi, says a company spokesperson.

Going into the conclave, the new Pope Leo XIV — formerly Cardinal Robert Prevost — had odds of less than 1%, according to Kalshi's website. Of the over 33,000 conclave trades placed on Kalshi, just 416 trades totaling to nearly $450,000 were placed on Prevost, the spokesperson says.

The highest payout on the platform was $52,641 on a $526 bet, adds the spokesperson. The identity of that bettor could not be confirmed by CNBC Make It.

The conclave was "a major draw, roughly comparable to a big sporting event," says the Kalshi spokesperson. Notably, $10.6 million on that platform pales in comparison to the amount spent on the most recent U.S. presidential election: $132 million, the company told MarketWatch in November.

Prediction markets operate similarly to futures, where users buy and sell contracts that pay out based on the outcome of a future event. They drew scrutiny and debate during the U.S. presidential election last year, over their potential to be used for manipulation and misinformation, and concerns about their regulatory status.

Large traders could potentially use such platforms to influence voter turnout on election day, Cantrell Dumas, director of derivatives policy for the advocacy group Better Markets, told CNBC on October 15.

Currently, Kalshi users can bet on a variety of events, from when the video game Grand Theft Auto VI will be released to what White House press secretary Karoline Leavitt will say during her next briefing.

Polymarket users can bet on similar outcomes, though U.S. users are currently barred from using the platform due to Commodities Futures Trading Commission regulations.

Like with all forms of betting, wagering on prediction markets can be a slippery slope. Financial experts typically recommend that you only bet what you can afford to lose, and to avoid repeatedly doubling down after a loss.

The biggest mistake to avoid: not setting a budget for yourself, Pikeville, North Carolina-based certified financial planner Jonathan Greeson told CNBC Make It on March 20.

"Your betting money should be included in your entertainment budget," Greeson says. "Like with investing, we should never bet more than we are willing to lose."

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