The decline was broad, and of the 30 most-traded stocks on the OMXS30 list, only five rose.
The best performer was the defense group Saab, up 7.4 percent. This came after Sweden and Ukraine reached an agreement on the sale and donation of up to 36 fighter jets to Ukraine.
At the other end, software company Octave fell 4.1 percent and engineering giant Alfa Laval fell 3.3 percent.
Medical technology company Elekta fell 13.2 percent after an interim report.
After new disputes and harsh words between the US and Iran, the price of oil rose 0.7 percent. A barrel of North Sea oil costs $95.
At the close in Stockholm, the stock exchanges in Frankfurt, London and Paris were also down. In New York, two of the three major indexes were up instead.
