When FanDuel and CME Group launched their joint-venture prediction market app in December, CME Group president Lynne Fitzpatrick specifically touted how the product would “enable a new generation of users to express their views” on sports, among other topics.

CME didn’t express any public misgivings about sports being included in FanDuel Predicts, even though sports wasn’t part of the partnership’s initial plan shared in August.

The vibes have changed dramatically, and without explanation, since then.

On CME’s earnings call Wednesday, CEO Terry Duffy criticized prediction market wagers related to sports events and suggested it is problematic for companies to use affiliated market makers on exchanges in which they have a financial interest. Those remarks came despite CME’s continued participation in facilitating sports wagers.

Duffy’s comments came less than 24 hours after the Commodity Futures Trading Commission (CFTC), the federal agency that oversees prediction markets, certified three wager types proposed by CME: bets on tennis tournaments, golf tournaments and college football games.

“A lot of these prediction markets on sports are gambling, and I think that that is going to find its way to the Supreme Court, and that is not something that we want to be a part of participating in right now,” Duffy told analysts on Wednesday. “A lot of these contracts are susceptible to manipulation when they list some of these small parlays and things of that nature, and those are not markets. Those are gambling.”

Fitzpatrick, who will succeed Duffy as CEO next year, added that CME wants “to be very careful” about sports event contracts.

CME has previously self-certified parlays—or “combos” in CFTC parlance. On Tuesday, more than 99% of the notional volume on its prediction market exchange came from sports betting.

Duffy also took aim at the concept of affiliated market makers, a setup where a company with a stake in a prediction market has a trading arm that enters bets against customers. Not only does FanDuel act as an affiliated market maker for prediction markets, but it has also boasted that market making is a revenue opportunity.

Affiliated trading arms are popular in the industry but have inspired concerns over conflicts of interest. “If it is participation in the markets in and of itself,” Duffy said, “I think that lends to certain credibility issues for that entity.”

“What has always excited us about our FanDuel partnership is the opportunity to get our financial markets in front of their [12 million] registered U.S. users,” CME said in a statement. “We also offer some sports products that meet regulatory standards as event contracts. Today, Terry referenced the sports-related contracts—like individual performance, combos and parlays—that sportsbooks and prediction market apps offer, but CME Group does not.”

FanDuel declined to immediately comment.

CME contributed $10.2 million in cash upfront for a 51% stake in FanDuel Prediction Markets Holdings LLC, according to SEC filings, but Wednesday’s earnings call was not the first sign of disconnect between CME and FanDuel.

Last month, Duffy compared the rise of prediction markets and other new CFTC-regulated products to what he saw in 2007, just before the U.S. plunged into financial crisis. While CME actively processes prediction market bets, it sued the CFTC for allowing Kalshi to offer perpetual futures, a different type of market that has no expiration date and encourages people to bet with borrowed money.

“The housing market has been supplanted by the speculation market, including predictions and everything else, and this could be a disaster waiting to happen,” Duffy said at the Piper Sandler Global Exchange & Fintech Conference.

The FanDuel Predicts app created through the FanDuel-CME venture recently began brokering bets through Crypto.com-owned Nadex in addition to CME Group’s exchange.

Earlier this year, FanDuel applied with the National Futures Association, where all exchange brokers must register, to be able to broker prediction market trades without CME’s involvement, theoretically from an entirely separate app. FanDuel hasn’t specified its intentions with that application.

CME expressed caution over the move.

“It’s important to note the difference between an application and a launch,” Fitzpatrick said on CME’s first-quarter earnings call earlier this year. “This actually doesn’t signify any change in our relationship or the partnership going forward. As Terry mentioned, and as you would expect, there are some contractual restrictions in terms of operating alternative venues during our partnership.”