The Federal Reserve on Wednesday put the dollar, which usually falls in December, on a downward trajectory nL1N1YP0EF.
The threat of a U.S. government shutdown and lower bond yields on the back of concerns of slowing economic growth also weigh on the dollar nL3N1YQ35W.
Those factors fuelled EUR/USD's biggest one-day rise of December on Thursday, according to prices on the EBS, which closed within the thick daily cloud which currently spans the 1.1389-1.1516 region.
EUR/USD's upside bias grows, the expectation is for eventual gains above the cloud top, as EUR/USD traders remain poorly positioned.
IMM data for the week ending Dec.
11 showed a futures market short an equivalent EUR/USD cash position of 7.0 billion euros, down from 7.6 billion the previous week, but EBS flow data since Dec.
11 shows many of the euro shorts may have been re-established.
Those worried about EUR/USD's upside risk can allay their fears by taking out insurance, by buying a two-week 1.1430 call option for a cost of 60 pips.
Profit potential is unlimited, if spot rises above the 1.1490 break-even point before the January 4 expiry.