One of the defining trends in markets this decade has been the extraordinary growth in global central banks' foreign exchange reserves.

Much of this money was channelled into western bond markets, helping to keep global interest rates lower than they would otherwise have been, fuelling investor confidence and boosting risk appetite and asset prices.

Now, however, the trend of rising reserve accumulation appears to be peaking, amid increasing signs of a global slowdown. This, analysts say, could add further fuel to the dollar's recent sharp rise. “This is a major shift in the markets,” says Bilal Hafeez, global head of FX strategy at Deutsche Bank. “Central banks are drawing down their reserves.”