At a rate of 9.46 kronor to the dollar, the Swedish krona has fallen 2.59 percent this year, according to the Bloomberg news agency's weekly dollar index.
It is the worst of all the so-called G10 currencies - the most traded and liquid currencies in the world.
Other G10 currencies struggling against the dollar include the Japanese yen, down 2.3 percent, and the Danish krone, down 1.98 percent.
The other end of the scale is topped by the Norwegian krone, which has risen 6.74 percent this year. The Australian dollar has also performed strongly, up 5.62 percent.
Last year, it was the Swedish krona that strengthened against the US dollar week after week.
