South Korea's LOTTE Corp. said it changed the preferred bidder for unit Lotte Card Co. Ltd. from private equity investor Hahn & Co. to another South Korean private equity firm MBK Partners.

The company said in a May 21 regulatory filing that the exclusive negotiation period with Hahn & Co. expired May 13 without an agreement. The company's board approved the change May 21.

Lotte Corp., the holding company of the Lotte business group, has until October to divest Lotte Card and stay in compliance with South Korean holding company rules. It currently owns 93.78% of Lotte Card.

The company did not reveal its reason for the change, but Yonhap News Agency cited an unrelated criminal complaint against Hahn & Co.'s CEO and disapproval from the trade union of Lotte Card as among the likely reasons.

Under South Korean law, any potential acquirer of a controlling stake should have a clean criminal record.

The company has chosen MBK Partners and its consortium partner Woori Bank to meet the tight deadline, the news agency said, citing a Lotte Corp. official.