NEW YORK (AFP, BLOOMBERG) - Wall Street stocks were mixed at the open Wednesday following Donald Trump's shock win in the US presidential election, as hopes of a pro-business agenda offset effects of higher uncertainty.

Turbulence in financial markets calmed after a knee-jerk selloff in stocks and rally in haven assets as investors reassessed the effects of Mr Trump's surprise victory.

Stock futures had initially plunged as results suggested the unpredictable Mr Trump was on his way to a defeat of Democrat Hillary Clinton, who had been viewed as a steady hand.

Two minutes into trading the Dow Jones Industrial Average was up 0.5 per cent at 18,423.79, while the Nasdaq Composite Index lost 0.1 percent to 5,189.33.

The S&P 500 Index rose as a surge in health-care shares offset losses in consumer and technology companies. Thirty-year Treasuries sank on wagers the Republican will boost spending, while shorter-dated notes rallied amid reduced bets on a Federal Reserve hike.

Mexico's peso plummeted on prospects the economic integration with the U.S. will unravel. Gold had one of the heaviest trading days ever, and the yen jumped on haven demand. Copper soared on the outlook for more infrastructure projects.

"It's an amazingly impressive recovery off the lows for risk assets," said Craig Collins, managing director of rates trading at Bank of Montreal in London. "It's very surprising given the feel the session had to start with, that it was a massive risk-off flight to quality bid. Now the early losses are getting erased and it looks like it could go unchanged on the day by the time the US gets in."

A Trump victory had been portrayed by analysts as having the potential to unhinge markets banking on a continuation of policies that coincided with the second-longest bull market in S&P 500 history. Going into the vote, most polls showed Democratic candidate Hillary Clinton ahead.

Mr Trump has pledged to clamp down on immigration to the U.S. and renegotiate free-trade agreements with countries including Mexico. In his victory speech, he pledged to focus on rebuilding U.S. infrastructure.

US stocks fluctuated as speculation Trump will pursue business-friendly policies offset some of the broader uncertainty surrounding his ascent.

Health-care shares surged as investors unwound bets that a win by Clinton would bring intense regulatory scrutiny. An ETF tracking biotech shares in the Nasdaq Composite Index rallied almost 10 per cent. Equity investors sent equity futures tumbling overnight as it became clear Trump would pull off a historic upset.

The Stoxx Europe 600 Index rose 0.6 per cent, after earlier dropping as much as 2.4 per cent. The MSCI Emerging Markets Index slid 2.4 per cent, paring losses of as much as 3.3 per cent after Mr Trump, giving his victory speech, sought reconciliation and cooperation with his political opponents. Benchmark gauges in Brazil, China and South Korea fell at least 2 per cent.