NEW YORK (AP) — A monthslong calm on Wall Street is breaking on Friday, and U.S. stocks are falling after President Donald Trump threatened to crank tariffs much higher on China.

The S&P 500 sank 1.5% and was on track for its worst loss since Aug. 1. The Dow Jones Industrial Average dropped 526 points, or 1.1%, after earlier tumbling as many as 597 points. The Nasdaq composite was down 2%, as of 12:15 p.m. Eastern time.

Stocks had been heading for a slight gain in the morning, until Trump took to his social media platform and said he’s considering “a massive increase of tariffs” on Chinese imports. He’s