1. American stocks suffered their steepest daily drop in months after China said it would increase tariffs on American-made goods in response to a similar move by the White House.

The S&P 500 fell 2.4 percent, pushing its loss for the month above 4.5 percent. Investors hammered shares in trade-sensitive sectors like agriculture, semiconductors and industrials. Just weeks ago, the S&P 500 reached a record. Above, the New York Stock Exchange on Monday.

China’s move will affect the roughly $60 billion in American imports already being taxed as retaliation for Mr. Trump’s previous round of levies; those imports include beer, wine, swimsuits, shirts and liquefied natural gas.