Why a Brexit could hurt emerging markets—and beyond

Brexit breeds uncertainty

Much has been said about how a U.K. exit from the EU could hurt the British economy. But the bigger point confronting investors may be what it does to the rest of the world.

If there's one near-definite result that experts can safely predict around a Brexit, it's this: A U.K. vote to leave the EU would increase the amount of uncertainty in markets. Since no concrete precedent exists for a Brexit or anything like it, market-watchers are predicting a global flight to safer assets. And that, in turn, would likely include an investor pullback from the world's emerging economies.

"We believe there is significant room for downside in the event of a leave vote," Yianos Kontopoulos, strategist at UBS, wrote to clients Wednesday.

In terms of which emerging markets, economic research consultancy Capital Economics says the nations likely to be hardest hit are those with the highest current account deficit as a percentage of GDP. Names that fit the bill include Colombia, South Africa, Peru and Turkey, which run deficits in excess of 4 percent of GDP.

"These are the economies that are most reliant on external financing and capital outside of their country for spending. Any acceleration in foreign outflows could really hurt these countries," Capital Economics said. Others that could take a hit include Mexico, Argentina and Brazil, all of which run a deficit of more than 2 percent of GDP.

Simon Quijano-Evans, the head of emerging-market research at Commerzbank, agrees.

Latin America "is next in line with regard to export exposure to the EU, while the whole of [emerging markets] and particularly the more open economies of Asia would be hit by secondary effects from any negative spillover a Brexit scenario would have on global growth," Quijano-Evans said.

It doesn't end with emerging economies

A Brexit could have profound implications for U.K. businesses, and by extension countries that do business with those U.K.-based enterprises. Emerging-market fund managers say the worst-case scenario is an economic recession in Britain, which would result in a dramatic decline in how much the U.K. trades with its partners.

"Most economies are still recovering from the financial crisis, and spillovers from the vote could be destabilizing," wrote Fergus McCormick, head of sovereign ratings at credit analysis firm DBRS.

Brexit blues or boom?

Capital Economics pointed out that a number of Eastern European nations are heavily reliant on the U.K. for exports. For Slovakia, Czech Republic and Hungary, exports to the U.K. made up roughly 4 to 5 percent of GDP in 2015.

Commerzbank in London downgraded the bonds of Hungary this week on the anticipation of Brexit.

It's still anyone's guess as to which parts of the market will be dramatically impacted given the lack of clarity around what happens after. Political strategists are estimating that the actual process of separating from the EU, should it come to that, could take up to two years.

Over the past six days, opinion polls suggest that the remain camp has been gaining momentum. However, many Londoners who have spoken to CNBC in recent days still give a sense that the vote could go either way.

"Anyone living in the U.K. will have been asked so many times in the past months about their views on the possible outcome of Thursday's referendum — the only answer one can give is we just don't know until the day after," said Quijano-Evans.