Shin Dong-bin, the chairman of Lotte Group in South Korea, has been registered as the head of an investment unit in Japan that is believed to be at the apex of the conglomerate's complex ownership structure, data showed Thursday.

The documents issued by the Japanese justice ministry showed that Shin was registered as the chief executive of 10 subsidiaries of the investment unit, dubbed "L Investment Company," as of July 31.

Previously, the investment affiliate was headed by Lotte founder Shin Kyuk-ho and Takayuki Tsukuda, chief executive of Tokyo-based Lotte Holdings.

L Investment Company holds a 72.65 percent stake in Hotel Lotte, which serves as a holding company of the retail conglomerate's businesses in the country, leading to speculation that the registration was part of Dong-bin's move to cement his footing.

Lotte, the country's fifth-largest conglomerate, is embroiled in an ownership dispute involving Kyuk-ho, 93, and his two sons, Dong-joo and Dong-bin, who had each controlled the company's operations in Japan and Korea until early this year. While Dong-joo was ousted from key positions at Japanese units, Dong-bin took the helm at Japan-based Lotte Holdings, the group's holding firm.

The seemingly smooth power transition took a nasty twist late last month when Kyuk-ho and Dong-joo tried to dethrone Dong-bin from Lotte Holdings.

In turn, Dong-bin demoted his father from general chairman of Lotte Holdings to honorary chairman, claiming that his age has weakened his mental and physical capacity. (Yonhap)