President Donald Trump said he'll announce his nominee to chair the Federal Reserve on Friday morning - and prediction markets have turned sharply toward a former Fed governor for the post.

It's now Kevin Warsh who's taking the lead in both Polymarket and Kalshi, just hours after Wall Street veteran Rick Rieder was seen getting the nod for the critical job.

"I'll be announcing the Fed chair tomorrow morning," Trump said in Washington at the premiere for "Melania," a documentary film about the first lady.

Rieder, chief investment officer of global fixed income at BlackRock $(BLK)$, was the favorite earlier today, ahead of three other finalists for Fed chair, including Warsh. The others are Kevin Hassett, who heads the White House National Economic Council; and Christopher Waller, a Trump-appointed Fed governor.

Trump had earlier promised an announcement next week, speaking at a cabinet meeting at which he also reiterated his longstanding criticism of the current chair, Jerome Powell.

On Polymarket, Warsh's chances of being named Fed chair were at 87%, with Rieder dropping to just 8%. Kalshi put Warsh at 86%.

Trump's comments came a day after the Fed held interest rates steady in a range between 3.5% and 3.75%.

The president has frequently called for rate cuts, and said in a social-media post Thursday morning that there was "absolutely no reason to keep them so high."

Earlier this year, analysts at Evercore ISI said that Warsh, as Fed chair, "would be more or less as dovish as Hassett" through the end of this year, meaning in support of lower interest rates, but that he would be more likely to step away from that stance in 2027 or 2028 if the economy got too hot.

Rieder has supported bringing rates down to 3%. "The Fed has got to get the rate down to 3% - I think that is closer to equilibrium," he said in a recent CNBC interview.