The dollar was on the defensive after a collapse in hopes of a further rise in U.S. interest rates this year drove its biggest daily fall.
The yen rose on Wednesday as weaker stock markets in Europe spurred investors to buy safe haven assets.
Short-sellers have Singapore stocks in their sights as the market struggles to find its footing as a smaller exchange hit hard by the commodity rout.
The U.S. dollar fell against the euro and yen on Tuesday after a drop in oil prices suggested U.S. inflation would stay low.
The U.S. dollar fell against a basket of major currencies on the view that the Fed would not be able to hike interest rates as quickly as forecast.
The dollar rose sharply on Friday, hitting a six-week high versus the yen.
The dollar hit a one-week low against the euro on Thursday after a plunge in U.S. durable goods orders.
Commodity-linked major currencies including the Australian and New Zealand dollars surged on Thursday as oil traded back above $33 a barrel.
The safe-haven yen and the low-yielding euro halted their rise on Tuesday, as stock markets and oil prices recovered.
The dollar edged down on Monday as renewed selling on oil markets drove investors into currencies often deemed less risky investments.
The dollar firmed Friday, boosted by expectations of monetary easing by in Europe and Japan, and by strong U.S. housing data.
The dollar turned negative against the euro on Thursday, reversing a morning rally.
The dollar fell to a more than one-year low against the Japanese yen as crude oil prices dropped near 13-year lows.
The economy of tiny Singapore is taking a big hit from China's slowdown just as the city-state is struggling with a homegrown demographic squeeze.
The dollar posted modest gains on Tuesday, as investor risk appetite improved on the back of rising oil prices and the expectation of further stimulus in China.
A recovery in stock markets helped the dollar gain ground against Europe's current safe havens of choice, the euro and the Swiss franc.
The dollar tumbled to a near five-month low against the yen and a 2-1/2-week trough versus the euro on Friday.
The dollar rose on Thursday, bolstered by gains in the U.S. stock market and a rebound in oil prices.
The euro regained its footing against the U.S. dollar as risk appetite soured anew late in the afternoon.
The dollar rose for a third straight session as gains on Wall Street and calmer financial markets enhanced risk appetite.