The Financial Market Authority in Holland has halted trading in shares of Swedish carmaker Saab's parent company until further notice.
The FMA gave no reason for halting trading in Swedish Automobile.
Shares in the troubled company were down 19% before trading was halted.
The fall followed a report in a Swedish newspaper that the company had hit further problems.
Saab entered Swedish bankruptcy protection in September. It is seeking new funding.
Production has been suspended at Saab's main plant in Trollhattan, Sweden, since April. Employees have not been paid since last month.