Soros warns of Brexit threat to pound
Writing in the Guardian, he said sterling would "decline precipitously" if the Leave camp wins Thursday's vote.
He made a fortune betting against the pound on Black Wednesday in 1992, when Britain left the ERM, and said Brexit would cause even bigger disruption.
But Vote Leave said the UK would be more prosperous outside the EU.
"The EU is costly, bureaucratic and blind to the impact it has had on people's wages and soaring energy bills," said Vote Leave chief executive Matthew Elliott, who accused Mr Soros of wanting to give more power to Brussels.
Mr Soros said in his article that leaving the EU would see sterling fall by at least 15%, and possibly more than 20%, to below $1.15 from its current level of around $1.46.
"The value of the pound would decline precipitously," he writes. "It would also have an immediate and dramatic impact on financial markets, investment, prices and jobs.
"I would expect this devaluation to be bigger and also more disruptive than the 15% devaluation that occurred in September 1992, when I was fortunate enough to make a substantial profit for my hedge fund investors.
"British voters are now grossly underestimating the true costs of Brexit. Too many believe that a vote to leave the EU will have no effect on their personal financial position. This is wishful thinking."
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