McDonald's Corp. is studying selling a stake in its loss-making Japan unit to a "strategic investor," as the world's largest fast-food chain reviews its global ownership strategies.

"We're exploring the sale of a portion of our ownership in McDonald's Japan if we identify a strategic investor who could help advance Japan's turnaround efforts and unlock our growth potential," said Chief Financial Officer Kevin Ozan, speaking on a conference call Monday.

McDonald's is seeking to sell as much as 33 percent of outstanding shares in the Japan unit and has met potential buyers including trading houses and investment funds, the Nikkei Shimbun newspaper reported in December.

Several funds including Bain Capital LLC and Permira likely have submitted bids, at levels significantly below what McDonald's is seeking, Nikkei reported last week without citation.

"We're in the early stages of the process and taking a thoughtful approach," said Ozan. The Japanese unit will continue to have a "franchisor, franchisee relationship" with Oak Brook, Illinois-based McDonald's "whatever may transpire with our ownership," he said.

McDonald's Japan has posted quarterly losses since mid-2014, as the chain struggled to win back customers turned off by a China food supplier scandal and incidents of foreign objects found in its food. It reported on Jan. 8 that same-store sales in December rose 8.8 percent as the Japanese chain introduced lower price items and limited-time offerings.

Comparable sales at McDonald's Japan rose 1.6 percent in the fourth quarter, helped in part by easier comparisons following the supplier scandal in July 2014, and as the unit executes a "revitalization plan" to strengthen the brand's appeal to customers, McDonald's CEO Steve Easterbrook said on Monday's conference call.