The founder of a failed Singapore oil trading company will be sentenced Monday for cheating banking giant HSBC out of millions of dollars in one of the country's most serious cases of fraud.

Lim Oon Kuin, better known as O.K. Lim, was convicted in May in the case that dented the city-state's reputation as a top Asian oil trading hub.

His firm, Hin Leong Trading, was among Asia's biggest oil trading companies before its sudden and dramatic collapse in 2020.

State Courts Judge Toh Han Li was due to sentence Lim at 2:30pm (0630GMT) Monday.

State prosecutors are seeking a 20-year jail term for the octogenarian businessman, saying "this is one of the most serious cases of trade financing fraud that has ever been prosecuted in Singapore".

The defence is seeking seven years imprisonment, playing down the harm caused by Lim's offences and citing his age and poor health.

The businessman faced a total of 130 criminal charges involving hundreds of millions of dollars, but prosecutors tried and convicted him on just three -- two of cheating HSBC, and a third of encouraging a Hin Leong executive to forge documents.

Prosecutors said he tricked HSBC into disbursing nearly $112 million by telling the bank that his firm had entered into oil sales contracts with two companies.

The transactions were, in fact, "complete fabrications, concocted on the accused's directions", prosecutors said, adding that his actions "tarnished Singapore's hard-earned reputation as Asia's leading oil trading hub".

'Unprecedented turmoil'

Lim built Hin Leong from a single delivery truck shortly before Singapore became independent in 1965.

It grew into a major supplier of fuel used by ships, and its rise in some ways mirrored Singapore's growth from a gritty port to an affluent financial hub.

The firm played a key role in helping the city-state become the world's top ship refuelling port, observers say, and it expanded into ship chartering and management with a subsidiary that has a fleet of more than 150 vessels.

But it came crashing down in 2020 when the coronavirus pandemic plunged oil markets into unprecedented turmoil, exposing Hin Leong's financial troubles, and Lim sought court protection from creditors.

In a bombshell affidavit seen by AFP in 2020, Lim revealed the oil trader had "in truth... not been making profits in the last few years" -- despite having officially reported a healthy balance sheet in 2019.

He admitted that the firm he founded after emigrating from China had hidden $800 million in losses over the years, while it also owed almost $4 billion to banks.

Lim took responsibility for ordering the company not to report the losses and confessed it had sold off inventories that were supposed to backstop loans.