Japanese drugmaker Daiichi Sankyo Co, which bought control of Ranbaxy Laboratories in 2008, said it believes unnamed former shareholders of the company hid information regarding US regulatory probes into Ranbaxy.
Last week, Ranbaxy pleaded guilty to felony charges related to drug safety and agreed to pay $500 million in civil and criminal fines under a settlement with the US Department of Justice.
"Daiichi Sankyo believes that certain former shareholders of Ranbaxy concealed and misrepresented critical information concerning the US DOJ and FDA investigations," the Japanese company said in a statement on its website, referring to the US Department of Justice and the Food and Drug Administration.
"Daiichi Sankyo is currently pursuing its available legal remedies and cannot comment further on the subject at this time," the statement said.
The Japanese company did not identify the shareholders.
Daiichi Sankyo, Japan's No. 3 drugmaker, bought a 63.9% stake in Ranbaxy for $4.2 billion in 2008. It bought shares from the controlling shareholder group, led by brothers Malvinder Singh and Shivinder Singh, as well as through a tender offer and an issue of new shares.
Reuters could not immediately reach the Singh brothers for comment after business hours on Wednesday through two of their companies. A mobile phone for Malvinder Singh, who was Ranbaxy's chairman and chief executive at the time of the sale, was unanswered.
"Daiichi Sankyo continues to support Ranbaxy in its efforts to address and correct the conduct of the past which led to the investigations by the US Department of Justice and the US Food and Drug Administration. These efforts include significant changes to Ranbaxy's management, culture, operations and compliance," the company said.