An octogenarian oil trader has been given a 17-and-a-half-year jail sentence in Singapore for defrauding HSBC, in a long-running case that sent shockwaves through the city-state’s commodity trading sector.

Lim Oon Kuin, known as OK Lim and once one of Singapore’s richest men, was sentenced on Monday after being convicted in May of “cheating” HSBC and abetting forgery. The 82-year-old founder of Hin Leong Trading was accused of encouraging a company executive to forge documents that tricked the bank into disbursing nearly $112mn.

Judge Toh Han Li of Singapore’s State Courts said the length of Lim’s sentence was designed to act as a “deterrent”. Prosecutors had sought a jail term of up to 20 years; Lim’s defence lawyer Davinder Singh argued for seven years, given his age and poor health. Lim attended court hearings in a wheelchair.