Following a probe in November 2020 by the
Commercial Affairs Department (CAD) into suspicious activities carried out by his two companies, Ng was arrested on 16 February 2021. On 22 March 2021, he was charged with cheating and "being a party to fraudulent trading". He posted S$1.5 million bail and remained under 24-hour monitoring. The following month, he was charged with forging bank documents. In July 2021, his bail was raised to S$4 million. According to the prosecution, as part of an alleged
Ponzi scheme that stretched from October 2017 till February 2021, Ng courted investors for funds to purchase
nickel metal from a company called Poseidon Nickel at a discounted price. The nickel would be resold for a profit to BNP Paribas Commodity Futures or Raffemet; Ng allegedly guaranteed his investors three-month profits averaging 15 per cent. About S$1.5 billion was invested in the alleged scam, with S$731 million returned to investors, and around S$1 billion owed to them. Ng's alleged scam reportedly ensnared some 300 victims; if convicted, Ng would have had executed the largest investment fraud in the history of Singapore. During his trial, one witness testified that two investors in his alleged Ponzi scheme "had died directly or indirectly because of pressure from this case." ==Personal life==