Shares in telecoms firm Ericsson fell more than 12% after its boss said it may have paid off Islamic State (IS) in Iraq to access key transport routes.
Chief executive Borje Ekholm told a Swedish newspaper an internal probe started in 2019 had found serious failings by staff and contractors.
Money was paid to access areas in Iraq that were controlled by IS, he told Dagens Industri.
He said the probe could not "determine the final recipients" of the money.
Mr Ekholm's comments came after a statement from the telecom equipment maker on Tuesday which admitted "serious breaches of compliance rules and the company's code of business ethics" regarding Ericsson employees, vendors and suppliers in Iraq between 2011 and 2019.
It said the internal probe, which had not been disclosed until now, had revealed "evidence of corruption-related misconduct".
It found Ericsson used alternative transport routes - sometimes controlled by terror groups such as Islamic State - as a way to avoid Iraqi customs.
The revelations have come into the public eye because of questions being put to the company by Swedish media and the International Consortium of Investigative Journalists
Ericsson said "several" staff members had left the company following the probe, even though it could not determine if Ericsson staff directly were involved in the suspect payments.