SINGAPORE (Reuters) - Singapore prosecutors on Monday filed 13 additional charges against a local businessman in relation to a scheme that allegedly raised more than S$1 billion ($746 million) from investors to fund bogus nickel trades. Authorities in the city state have implicated Ng Yu Zhi, a former managing director of trading companies Envy Global Trading (EGT) and an inactive firm, Envy Asset Management, in the fraud scandal, one of the biggest in Singapore. According to the charge-sheets, prosecutors allege that Ng cheated nine individuals and three corporate entities of about $63.6 million in connection with EGT’s non-existent forward nickel contracts. They also allege he committed “criminal breach of trust by dishonestly misappropriating” a sum of at least S$201.2 million between August 2020 and February 2021 while being the director of EGT. The number of charges against Ng now stands at 31. The scheme purportedly raised about S$1.5 billion from nearly 1,000 investors, with about S$731 million of this later withdrawn by investors, according to interim judicial managers at accounting firm KPMG. Authorities have previously said at least S$1 billion was raised in the scheme, which ensnared the likes of lawyers and fund managers. Ng and his lawyer did not immediately respond to requests for comment. Ng has not previously made any public comment on the charges and has been removed from his role as managing director of EGT. If convicted, Ng faces a jail term of up to seven years on each of the fraudulent trading charges, while cheating is punishable with up to 10 years per count. Criminal breach of trust carries a punishment of imprisonment of up to 20 years. ($1 = 1.3436 Singapore dollars) Reporting by Aradhana Aravindan in Singapore and Mai Nguyen in Hanoi; Editing by Ed Davies Our Standards: The Thomson Reuters Trust Principles.