Trump sent the U.S. stock market on a jagged round trip after saying he had “talked about the concept of firing” the head of the Federal Reserve.

Dow Jones futures fell slightly overnight, along with S&P 500 futures and Nasdaq futures. United AirlinesUAL reported mixed results late Wednesday. NvidiaNVDA chipmaker Taiwan SemiconductorTSM ...

The trading action Wednesday hinted at how Wall Street would react if Trump actually removed Powell — a prospect that ...