Federal Reserve Chairman Kevin Warsh signaled the central bank may not be done fighting inflation, a stance that boosted bond yields and led to choppy trading in stocks.

Short-term Treasury yields moved higher as his comments at the Kansas City Fed's annual conference in Jackson Hole, Wyo., this morning were taken as a sign that interest rates could rise soon. The 2-year Treasury yield recently traded at 4.35%, up from about 4.23% before the speech in a move that would be its biggest one-day increase since June.

The S&P 500 initially rose after Warsh's speech, then turned lower. The dollar rose, moving higher with bond yields, while gold prices fell.

Traders had been hopeful that Warsh, more tight-lipped than his predecessors, would offer a read on the economy and reassure markets that the central bank remains ready to raise interest rates if needed.

The Nasdaq composite and chip stocks fell after Marvell Technology's earnings disappointed investors. Though the semiconductor company lifted its guidance and reported higher revenue and profit, shares sank 10%, the latest sign of the high bar investors have set for AI-linked companies.

Oil prices are retreating, with Brent crude futures trading at about $88 a barrel.