On the OMXS30 list of the most traded stocks, Ericsson fell the most, down 6.3 percent.
This follows an analysis by investment bank ABG Sundal Collier that U.S. chipmaker Nvidia is developing a chip for 6G mobile networks that could eventually compete with Sweden's Ericsson and Finland's Nokia.
Nokia fell 6.8 percent.
Boliden also struggled, down 4.3 percent after major bank Goldman Sachs gave the mining group a sell recommendation.
At the close in Stockholm, the exchanges in Frankfurt and London had fallen, while Paris had risen. In New York, all three major indexes were down.
The price of oil fell 3.5 percent during the day. A barrel of North Sea oil cost $91.
