The main US stock barometer posted its steepest sell-off since October as volatility came roaring back amid mounting anxiety over US government policy.
The S&P 500 index dropped 1.2 per cent to 2,344, the Dow Jones Industrial Average fell 1.1 per cent to 20,668 and the Nasdaq Composite slumped 1.8 per cent to 5,793.8.
The bout of bearishness snapped a streak of 109 days in which the S&P 500 did not close lower by more than 1 per cent.
Investors have become more skittish over US government policy as the Trump administration faces a tougher time than some had expected in attempting to pass legislation that repeals the Obamacare reform.
The administration has said it intends to act on healthcare before it can turn to initiatives that businesses are eagerly awaiting, including a reduction in the corporate tax rate and an infrastructure spending programme.
The S&P 500 financial sector was the worst performer by a wide margin, shedding 2.9 per cent. Banks faced particularly strong pressure, tumbling 3.9 per cent in the biggest rout since the days following the Brexit vote in June.
Other economically sensitive shares also notched solid losses, with technology and industrial stocks each sliding 1.5 per cent.
Small-cap stocks, seen as proxies for investor sentiment on the economy, also fell sharply. The Russell 200 index skidded 2.7 per cent, surrendering its gains for 2017.
Meanwhile, investors rotated into havens. The utilities sector, which is favoured in times of strife because of its consistent dividends, jumped 1.4 per cent.
Treasury prices were also in the black, sending yields lower. The yield on the 10-year dipped by 4.9 basis points to 2.4229 per cent.
Get alerts on Markets when a new story is published