Industrial companies weighed the most among the most traded stocks in the OMXS30 index, with price falls for Atlas Copco and Alfa Laval of 2.5 and 2.2 percent, respectively.
Other heavy losers were the Wallenberg sphere's power company Investor, down 2.5 percent, and pharmaceutical company Astra Zeneca, down 3.4 percent.
Among others, the major banks went against the trend. Best in the OMXS30 was Swedbank, which increased 2.1 percent.
Car manufacturer Volvo Cars rose 0.7 percent after an unexpectedly strong sales figure for August and an adjustment of the company's financial targets.
Telecom operator Tele2 rose 0.9 percent after the announcement that CEO Kjell Johnsen is leaving.
The stock market downturn accelerated after payroll administrator ADP reported an unexpectedly weak job figure for the private sector in August in the USA. This gives a gloomy forecast for the labor market in the USA ahead of the major job figure for the entire economy, excluding the agricultural sector, on Friday.
The Stockholm stock exchange has started September weakly and has fallen 2.3 percent this week, but since the turn of the year, the OMXS index is up 7.3 percent.