Local shares slid last Friday, leading the NZX 50 to its second weekly decline as investors favoured safe-haven assets such as bonds and gold ahead of this week's referendum.
A Mail on Sunday poll in Britain - the first conducted after Cox's murder - puts the "remain" bloc at 45 per cent while 42 per cent endorsed leaving the EU.
A Sunday Times poll, a third of which was conducted before the Cox attack, put the "remain" camp on 44 per cent and "leave" on 43 per cent. The results of the referendum are expected on Friday night, New Zealand time.
The head of private wealth research at Craigs Investment Partners, Mark Lister, said the "Brexit" vote was the biggest event financial markets had seen in a while.
"Markets are right to be nervous. A Brexit would certainly hurt the UK, dent sentiment in the already fragile Eurozone and provide another worry to add to an already crowded list," Lister said yesterday.
"If I had to put money on it, my guess would be that the UK will choose to stay, but not by much. That would spell a modest relief rally, particularly for those share and currency markets that have been sold off the most. If they do go, the moves we have seen during the last few weeks will continue, but with more vigour."
Hamilton Hindin Greene sharebroker Grant Williamson said local investors should count on stockmarket volatility this week, which he expected to grow in intensity in the leadup to the vote.
"Obviously [the vote] will impact all equities markets. Investors will be trying to position themselves accordingly, probably looking to reduce a bit of risk. There will be continued volatility on markets as we get closer to Friday our time."
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Liquid stocks were more likely to be exposed, Williamson said.
"Fletcher Building, Spark, those are the type of stocks that will show most volatility."
The Kiwi dollar was buying US70.49c on Friday evening and 49.11 pence as the pound strengthened.
Westpac senior market strategist Imre Speizer did not think people would be placing heavy bets that would swing markets one way or the other before the vote.
"The big moves are going to be in response to the outcome," Speizer said.
"If they vote to leave, I think the Kiwi would easily punch through 50 [pence]. Conversely if they stay, you should see it move back to easily 46 [pence], maybe lower.
"If they left you'd see all the high-risk markets being sold and the safe-haven markets being bought. So that would hurt the Kiwi quite hard, the Kiwi currency on its own is a risky currency ... you'll get a lot of US dollar buying. People will be piling into Treasury bonds, putting their money into the safety of US dollars and you get the likes of the Aussie and Kiwi being sold heavily."
- Additional reporting agencies
