The Dollar Carry Trade
One other reason to sell the dollar is interest rates. Why not borrow in dollars where interest rates are low and invest elsewhere where yields are high? This is what is known as the carry trade.
In the past decade, the Japanese yen and the Swiss franc were favorites for the carry trade because of their low yields. But now, the U.S. dollar presents the same opportunity due to the likelihood that rates will stay low for a long time to come.
The video below explains.
See also Is the Dollar Set to Become the New Yen? from Market Beat.