"Brexit was so unexpected that it very much caught everyone off-guard. This election, markets were possibly a little bit more on edge given we've already had one Brexit this year. I think it's taken less to spook markets this time around, but we are still seeing some very big moves like we did on June 24 when the UK decided to leave the EU."
S&P 500 futures are down the most since Brexit while the Mexican Peso has dropped the most the most since 2008.
Shane Solly, portfolio manager and analyst at Harbour Asset Management, said a number of leading stocks had been "poleaxed" as the voting showed a swing towards a victory for Trump.
"There is a high level of uncertainty and we are not done yet," he said.
"The swing towards Trump has caught a lot of markets out. The strong showing by the Republicans has certainly riled the markets."
The S&P 500 futures were down 5.2 per cent as at 5:30pm, said Stephen Bennie from Castlepoint Funds. According to CNBC NASDAQ and S&P 500 have halted futures trading for the time being.
US S&P stock futures plunged by 5 per cent or "limit down" - the maximum decline permitted before trading curbs kick in.
That points to Wall Street's S&P 500 market opening more than 5 per cent overnight.
"We're in a sort of Brexit times two situation. Ultimately the markets recovered reasonably well from Brexit," Bennie said.
"This is potentially bigger and it will be a little bit longer before it becomes clear what is going to be the impact of having Trump as US president,"
Among the bigger New Zealand stocks to be sold off were Fletcher Building, down 37c or 3.75 per cent at $9.50, Spark down 14c (3.9 per cent) at $3.43, Fisher and Paykel Healthcare down 40c ( 4.4 per cent) at $8.60 and Xero down $1.05 (5.8 per cent) at $16.95. While analysts said the market had suffered heavily, they pointed out that the market had been extremely buoyant over the last year, and that the selling had returned the NZX-50 index back to June levels.
Shortly after 3.30pm the NZX50 was down 3.54 per cent after being in positive territory since the market opened this morning.
The ASX200 across the ditch was down 3.6 per cent at the same time. One broker compared the afternoon to the shock of the Brexit referendum.
Investors are unloading shares as prospects for a Trump presidency appear to be rising. Dow futures have tumbled 3.5 per cent or 643.00 points to 17,647.00 and S&P 500 futures are down 4.1 per cent or 86.50 points at 2,049.00.
The markets are foreseeing a Donald Trump win, a Westpac market expert says.
The US Presidential race appears still too close to call, but Westpac senior markets strategist Imre Speizer said about 3.25pm that the markets had become volatile in the last hour.
"Up until the last one hour markets were opining that Clinton was looking like getting the win and that's swung around to thinking Trump's going to get the win," he said.
The best indicator of this was the Mexican Peso currency against the US dollar.
"Over the last hour that one has really swung around and has weakened considerably against the US dollar," he said.
"In addition, other good indicators are things like US Treasury yields, which were rising over the last half a day and from the last hour ago they plunged about 15 basis points, which is a lot."
He added that the US Dollar-Yen rate had plunged, as had the Australian-US and Kiwi-US.
ThinkMarkets, a London-based brokerage, has already called the whole race for Trump according to Bloomberg.
The Mexican Peso has risen from 18.2 to 20.1 to the US dollar.
S&P 500 futures were down 3.8 per cent at around 3:30pm, said Stephen Bennie from Castlepoint Funds.
"I think the markets are becoming a bit concerned about a Trump victory," Bennie said.
The market has fallen straight back to the same level as before the FBI cleared Hillary Clinton of any criminal wrongdoing over her personal use of an email server.
The markets are treating a Trump victory as a live possibility, Bennie said.
Mark Lister, of Craigs Investment Partners, said markets were "more than nervous".
"Since you've seen Trump pick up a couple of states and some of the polls in crucial battle ground states go his way, markets have very quickly woken up to the fact that this is going to be a lot closer than they might have thought," he said.
"Markets remember the Brexit situation very clearly where they all got caught wrong-footed, were too complacent and things got messy for a few investors."
He said it was "eerily similar" to what happened during the Brexit vote earlier this year.
"But there's still a lot of states to be counted," he said.
JB Were strategist Bernard Doyle said the results so far were much closer than the market would have liked.
"We're not pretending to try and judge the outcome yet but I think the way the market's behaving, certainly the risk of Trump winning is getting baked-in to at least a coin flip, based on some of the stuff we're watching, even possibly stronger odds than that."
He said US stock futures were down 4 per cent, the New Zealand market was down about 3 per cent and US bonds have rallied about 10 basis points - "classic flight to safety-type of behaviour".
"I guess the only thing that's surprising me a little bit is that the Kiwi dollar's been pretty reasonably resilient. "