Central banks in the developing world have lost $81 billion of emergency reserves through capital outflows and currency market interventions since early May, even before the recent renewal of turmoil in emerging markets.
The figure, which excludes China, is equal to roughly 2 per cent of all developing country central bank reserves, according to Morgan Stanley analysts, who compiled the data from central bank filings for May, June and July.
However some countries have suffered more precipitous drops. Indonesia has lost 13.6 per cent of its central bank reserves between the end of April and the end of July, Turkey 12.7 per cent and Ukraine burned through almost 10 per cent. India, another country that has seen its currency pummeled in recent months, has shed almost 5.5 per cent of its reserves.
"It's a real regime change compared to what we have been used to for the past decade," said James Lord, a Morgan Stanley strategist. "We saw huge reserve accumulation as emerging markets tried to stem currency appreciation, but now we're seeing the exact opposite."
Central bank reserves are held to act as a safety buffer against turmoil, and are on average still far larger than during past emerging market crises. But the pace of of the drops have spooked some investors and analysts.
Many central banks are likely to have suffered further reserve depletion in August, as the turbulence caused by the US Federal Reserve's plans to end its monetary stimulus has resumed, and compounded concerns over slowing economic growth in emerging markets.
Analysts at Bank of America point out that interventions may in fact be counter-productive, as central banks are forced to sell US Treasuries to buy their own currency. This pushes up Treasury yields, both increasing the turmoil in emerging markets and lessening the value of their remaining Treasury reserves.
Asset managers and analysts predict that central banks will soon have to give up supporting their currencies directly and take more decisive steps to stanch the money flowing out of their economies.
"If they keep intervening they will keep burning through reserves," said Michael Wang, a strategist at Amiya Capital, an emerging markets-focused hedge fund. "Central banks are probably waking up to the realization that that's not sustainable."
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Some central banks have already begun to raise interest rates to buttress their currencies, most recently Turkey earlier this week. But more rate rises are expected in the coming months, despite the sluggish growth environment.
Citi downgraded its growth forecasts for emerging markets again this week, to 4.6 per cent this year and 5 per cent in 2014. The US bank's economists pointed out that excluding China and the oil-rich Gulf states, the current account balance of emerging markets as a whole has deteriorated from a 2.3 per cent surplus in 2006 to a 0.8 per cent deficit this year – the biggest shortfall since 1998, the last time the developing world was gripped by crisis.
"Ultimately most of the countries with large current account deficits will have to hike rates by more if they want to better protect their currencies," Mr Lord said.
Some central banks are still accumulating foreign currency, however. Lithuania, Poland, Israel, Latvia and Colombia all saw their reserves grow by at least 1 per cent between May and July, according to Morgan Stanley's figures. Others, such as Brazil and Russia, still have ample foreign reserves despite propping up their currencies.