US stocks were mixed Thursday after a rough session the day before, as investors eyed potential progress on trade talks and President Trump lashed out at Fed Chair Jerome Powell after his stark picture of the economy under tariffs.

The Dow Jones Industrial Average (^DJI) fell 1.7%, or over 600 points. The benchmark S&P 500 (^GSPC) fell 0.3%, and the tech-heavy Nasdaq Composite (^IXIC) erased earlier gains to fall 0.7% after Wednesday's tech-led sell-off.

Shares of UnitedHealth (UNH) tanked as much as 19% in early trading, dragging the Dow lower, after the health insurer cut its full-year profit forecast. UnitedHealth is the largest Dow component by weight.

Stocks slid on Wednesday as Powell, speaking in Chicago, issued his starkest warning yet on how tariffs could affect the US economy. The Fed chair said the central bank would likely face a "challenging scenario" considering he expects the levies to exacerbate inflation and slow economic growth.

Read more: The latest on Trump's tariffs

Powell also threw cold water on hopes the central bank would imminently slash interest rates as tariffs roll in, saying Fed officials will "wait for greater clarity" on Trump's trade policy.

Before and after Powell spoke, Nvidia (NVDA) shares tanked on news that the chip giant would face new curbs from the US government on sales to China. Shares were flat on Thursday.

Wall Street's corporate focus will turn to Netflix's (NFLX) quarterly earnings report, which is set for release after the bell. With Big Tech unsettled by Trump's tariffs, the streaming giant has emerged as a rare bright spot among the group, and investors hold high hopes for its results. 

Meanwhile, TSMC (TSM) reported a 60% surge in first quarter net profit on Thursday, topping forecasts as booming demand for chips used in AI applications drove strong growth at the world’s largest contract chipmaker.