Some prediction market platforms have received warnings from the U.S. Commodity Futures Trading Commission (CFTC) not to use U.S.-style gambling odds, The Block reported on Aug. 7, citing Bloomberg News.

The move comes as the CFTC seeks to assert jurisdiction over sports betting.

Bloomberg said the CFTC sent letters to regulated entities urging them to comply with the law and avoid "deceptive" practices in listings, advertising and solicitations, citing the letters obtained by Bloomberg. U.S.-style odds, also known as moneyline odds, use plus or minus signs to show how much a bettor would win on a $100 bet.

Prediction markets, by contrast, show probability directly as a cents price. That price can be converted into U.S.-style odds with a simple calculation: below 50 cents it becomes plus odds, and above 50 cents it becomes minus odds.

The CFTC cited research in the letters saying the U.S.-style betting format encourages risky bets in sports betting, Bloomberg reported.

A Kalshi spokesperson said in an emailed statement that, as a federally regulated exchange, it follows CFTC guidance and will comply by the deadline set in the letter. Polymarket and the CFTC did not respond to requests for comment.