Lotte Group's chairman, Shin Dong-bin, who is serving 30 months in jail after being convicted in a corruption scandal, more than doubled his stake in Tokyo-based Lotte Holdings Co., Yonhap News Agency reported Feb. 22.

Shin increased his stake from 1.38% to 4% and became the largest individual shareholder in the company, the news agency reported, citing a recent regulatory filing from the company.

The move to increase his stake could be an attempt by Shin to secure managerial control over Lotte Holdings after he resigned as chairman of Lotte Holdings on Feb. 21, according to the Yonhap report. The board of Lotte Holdings subsequently approved Shin's resignation Feb. 21, the report said.

A Lotte official told Yonhap News Agency that the share purchase is a private matter and declined to confirm the time, purpose and source of the purchase.

Shin was sentenced to prison in early February on bribery charges in connection with a corruption scandal that eventually led to the impeachment and trial of former South Korean President Park Geun-hye.