US investigators joined an investigation into Mirror Trading International, seen as 2020’s biggest cryptocurrency scam, to help liquidators of the South African scheme recover the assets of out-of-pocket investors. Fin24 reports that the collapse of MTI, which in November said it had 260,000 members around the world and 23,000 Bitcoin worth about $885 million (or about N$13 billion) shone a spotlight on the safety of South Africa’s booming cryptocurrency market. Its overseers have asked a South African court to declare the operation unlawful and the nation’s financial regulator has called it a Ponzi scheme.