Japan’s Securities and Exchange Surveillance Commission (SESC) is investigating possible insider trading around the takeover by Wal-Mart of Seiyu Ltd in 2007, local media reports have said.

The US retail giant completed a tender offer to acquire total control of former Japanese subsidiary Seiyu in December 2007. However, Wal-Mart Stores is now said to be cooperating with an investigation into possible insider trading connected to the transaction, the news agency Reuters said.

“We have fully cooperated with the authorities for their investigation and will continue to do so,” said Kumie Wama, a Tokyo-based spokeswoman for Wal-Mart was quoted by Reuters saying.