President Donald Trump is pushing stocks to sink again on Friday, this time after threatening 50% tariffs on the European Union that could begin in a little more than a week. The S&P 500 was down 0.9% in early trading and on track for its worst week in the last seven.

Wall Street slumped under the weight of pressure from the bond market, where Treasury yields climbed on worries about the U.S. government's spiraling debt and other concerns.