Regulators Probe Kalshi 'Mention Markets' After Trump Bet Flap

Federal regulators have opened a review of so-called "mention markets" on prediction platforms, where bettors wager millions of dollars on whether a public figure will say a specific word, according to two people with direct knowledge of the probe who spoke to NPR anonymously because they were not authorized to discuss it publicly.

In response, Kalshi, the largest U.S. prediction market, has pulled all mention markets tied to sports "until further notice" while the Commodity Futures Trading Commission conducts its inquiry, one of the people said. Sports betting on the site typically involves game outcomes, but wagering on whether a sportscaster will say words like "MVP" or "redshirt" had grown increasingly popular. Sports wagers make up more than 80% of the billions traded weekly on Kalshi, so removing mention markets will significantly shrink that category. Kalshi is still allowing bets on what people say at political events, earnings calls and television newscasts.

The scrutiny follows a high-profile incident that reached the White House. Last month, regulators revealed that President Trump's longtime teleprompter operator had used Kalshi to profit from correctly betting on words the president would or would not utter during public appearances. Kalshi said its internal surveillance flagged the suspiciously well-timed bets and reported them to federal authorities.

"These mention markets are not popular across the political aisle," said the second person familiar with the probe, who requested anonymity to discuss internal CFTC deliberations. "They are potentially very easy to manipulate, so the CFTC is taking a hard look at whether some of them make sense."

Spokespeople for Kalshi and the CFTC declined to comment. Polymarket, Kalshi's main competitor, offers mention markets only on its overseas site, which the CFTC does not regulate; its U.S. service does not list them.

Most prediction markets are "self-certified," meaning operators can launch a market by filing paperwork asserting it complies with rules governing a type of financial derivative called a swap — including a requirement that the market not be "readily susceptible to manipulation." Regulators and Kalshi's own lawyers increasingly worry some mention markets run afoul of that principle.

Inside Kalshi, employees have debated the usefulness of mention markets, with co-founder Luana Lopes Lara championing them as a way to draw new users beyond sports bettors, according to a former Kalshi employee. The markets have also produced odd outcomes: during the World Cup final broadcast on Fox, a sportscaster mistook Matt Damon for Brad Pitt, and Kalshi's market settled on Pitt attending per its rules — even though he was not there. Bettors who wagered Pitt was absent collectively lost $287,866, according to Kalshi data.