The euro shot up more than two cents against the dollar Friday after a summit of eurozone leaders in Brussels agreed on stronger actions to reverse the spiralling crisis.
At 2100 GMT the euro traded at $1.2654, up from $1.2442 late Thursday.
The deal squeezed out of tough talks between the eurozone's biggest powers early Friday was the catalyst for the jump.
They agreed to use emergency funds to support ailing banks directly and to ease pressure on governments' debt burdens through bond purchases; and to inject 120 billion euros ($150 billion) of stimulus money into the suffering euro area economy.
"The low expectations in place the past few days surrounding the eurozone summit were tossed aside with ease on Friday, as new measures proposed prompted a massive short-covering rally in the euro," said Christopher Vecchio of Daily FX.
US bond yields jumped as investors moved into riskier currencies; Spain and Italy bond yields dropped sharply.
"The summit is a clear success. It goes very clearly in the right direction because at last it puts in place efficient tools in the long term," Natixis bank bond strategist Rene Defossez said.
The yen headed lower as the appetite for risk grew. The euro bought 101.02 yen, compared to 98.85 yen Thursday. The dollar was at 79.83 yen, up from 79.45.
The British pound rose to $1.5707 from $1.5515. The dollar fell to 0.9489 Swiss francs from 0.9650.