Former oil tycoon Oon Kuin Lim has appealed his 17.5-year prison sentence in a series of legal battles stemming from the high-profile demise of Singapore commodity trading business, Hin Leong Trading Pte. Ltd.

Lim, better known as O.K. Lim, was convicted last week on three charges of cheating and abetting forgery against banking giant Hongkong Shanghai Banking Corporation (HSBC), with his bail of $4 million having been extended. The trial was one of Singapore’s largest reported fraudulent trading cases.