Traders See Profits Evaporate in Minutes as Trump Convulses Bets

The early days of Donald Trump’s trade war have been marked by a flurry of advances and retreats, forcing traders to adapt by increasingly making bets that are more conservative than usual or easily reversed.

“The market is trying to predict and trade off a very unpredictable situation and person,” said Antony Foster, the London-based head of Group-of-10 spot trading at Nomura International Plc, who has taken to running smaller positions on currencies. “You could look like a hero one minute, only for the situation to turn on a sixpence and you look like a zero the next.”

As ...