Stocks in the United States ended the day sharply lower, a sign that investors might have growing concern over the turmoil in Washington.
• The Standard & Poor’s 500-stock index ended down 1.8 percent.
• The Dow Jones industrial average also fell by 1.8 percent. The index lost more than 370 points, its biggest one-day decline since President Trump was elected.
• The dollar was weaker against other major currencies.
And Wall Street’s fear gauge is up. After hitting historic lows, the Chicago Board Options Exchange volatility index, or VIX, spiked more than 35 percent on Wednesday, although the index remains well below its historical average.
The turnabout was surprising because of a long period of complacency that preceded it.
Among the reasons for the sudden skittishness:
Concerns that the president’s tax and regulation agenda may be delayed
New revelations about Mr. Trump’s sharing of sensitive information with Russian diplomats, and his reported suggestion that former F.B.I. director James B. Comey drop his investigation into former national security adviser Michael T. Flynn are raising fears that Mr. Trump’s agenda of lower taxes and lighter regulation could be harder to enact.
Underlying weakness in the economy
While strong tech stocks have been inflating the major indexes in recent months, some key companies for the American economy — especially retailers and carmakers — are facing real struggles.