The currency forecast to perform the worst in emerging markets this year is the one benefiting most from the rush to boost returns in the wake of the UK's Brexit vote. The rand has strengthened 4.9% against the dollar since the day before the UK voted to leave the EU on June 23 - the most among 31 major and developing-nation currencies and bringing gains this year to 11%, trailing only Brazil's real and the Japanese yen.But analysts warn that the currency might give up those gains through the rest of the year - though it is showing few signs of doing so right now.The odds seem to be stacked against the rand. The economy contracted in the first quarter and South Africa might soon have its credit rating cut to junk.Yesterday's local government elections probably also added to the country's political risk.But, for now, nothing is deterring the wall of money seeking returns as developed-nation policymakers keep interest rates low to stimulate their economies."Investors are not paying attention to underlying fundamentals or risks, but just diving head first into the pursuit of returns," said Peter Rosenstreich, head of strategy at Swissquote Bank in Switzerland."It's whitewashing a lot of emerging-market sins."Reduced bets for US rate increases and prospects for more stimulus in Europe, the UK and Asia are spurring demand for higher-yielding assets.Foreign investors bought a net R9.1-billion of South African bonds last month, bringing inflows this year to R50.2-billion, compared with R13-billion in the same period last year, helping to prop up the currency.South Africa's central bank has raised its key interest rate twice this year to 7%, offering attractive returns for investors who borrow dollars to buy higher-yielding currencies.The rand returned 6.7% for carry-trade investors last month, more than double that of the next-best currency, the South Korean won."The rand is one of the most liquid currencies and one of the highest yielders. Such a combination makes it very attractive in the low-yield environment," said Piotr Matys, a strategist at Rabobank in London."South Africa is still a relatively attractive investment, largely because the rest of the world is so unattractive," said Nigel Rendell, a senior emerging-markets analyst at Medley. ..