Business daily Dagens Industri (DI) reported on Tuesday that CEO Martin Lundstedt bought a large number of shares on January 30th, several weeks before the offer was made. If the Volkswagen bid were to be accepted, Lundstedt would make 1.7 million kronor in profit, DI calculated.

Also finance head Jan Ytteberg bought shares on the same day to the tune of a half million profit in case of a successful German take-over. 

Due to their standing and insight into the company's affairs, Lundstedt and Ytterberg must by law report any changes to their shares portfolio to Sweden's Financial Supervisory Authority (Finansinspektionen – FI). 

"If you have insider information you cannot act based on that information regardless of whether you report the transaction to us or not," trade survey unit head Johan Allstrin told the TT news agency on Tuesday.

Any criminal probe, however, would be instigated by the Swedish police's financial crimes division.

As rumours were already swirling that Volkswagen would try to up its stake in the Södertälje-based company, some observers said they were surprised the two top managers would even ponder making such shares purchases. 

"It's remarkable that such high-level bosses dared go in and trade," net broker Avanza spokesman Claes Hemberg said about the the case. "They probably did not know about the bid, as then they wouldn't have had the courage to do so, but they should have been thinking long-term."