Crises in Libya, Japan, Bahrain and Yemen did little to curb market enthusiasm Monday, with the positive mood leading foreign exchange traders to seek out riskier currency deals.
"While international developments were mixed over the weekend, financial markets are focusing for the most part on the 'good news,'" said Wells Fargo's Nick Bennenbroek.
"Risk appetites are improving as a result, and the US dollar, yen and Swiss franc are slipping on some lessening in safe-haven support."
The European single currency continued its upward progress against the greenback, changing hands at $1.4226 from $1.4176 on Friday.
The pound was at $1.6311 versus $1.6235).
"The yen is also lower again today following the coordinated FX intervention by the G7 countries on Friday," said Bennenbroek.
The dollar rose to 81.07 yen at around 2115 GMT, from 80.59 yen late in New York on Friday.
The yen soared briefly to a post-World War II high of 76.52 yen to the dollar last week, raising concerns that its over-valuation could harm Japan's attempt to rebuild after the March 11 earthquake-tsunmai disaster.
The dollar stood at 0.9047 Swiss francs (0.9006).