The yen reached a post-World War II high versus the US dollar, gaining for a second week and spurring speculation that the Bank of Japan will move to weaken the currency as concern that global growth is faltering fuels demand for refuge.
The euro had the biggest weekly increase against the US dollar in a month.
The US dollar dropped against the yen amid speculation that US Federal Reserve Chairman Ben Bernanke may say next week that added measures may be needed to support the economy. The Swiss franc fell on bets that the central bank would move to weaken it.
“There seems to be more pressure for safety than anything else,” said Fabian Eliasson, head of US currency sales at Mizuho Financial Group Inc in New York. “With all these uncertainties, there’s going to be pressure on the downside for dollar-yen.”
The Japanese currency appreciated 0.2 percent to ￥76.55 per US dollar in New York, from ￥76.71 on Aug. 12, touching a postwar high of ￥75.95 on Friday.
The euro rose 1.1 percent to US$1.4397, from US$1.4248, and gained 0.8 percent to ￥110.20, from ￥109.30. The franc fell 0.9 percent to SF0.785 per US dollar and dropped 2 percent to SF1.1303 per euro.
The pound gained 0.7 percent against the euro this week to ￡0.8697. Britain’s currency rose 1.6 percent versus the US dollar to US$1.6542.
Sterling has strengthened 1.2 percent in the past week against a basket of nine other developed-market currencies.