David Merino, the alleged mastermind behind Spain's largest cryptocurrency Ponzi scheme, FX Winning, has been arrested in Dubai. The scheme, which defrauded over €460 million from approximately 15,000 investors, promised high returns on forex and cryptocurrency investments. Despite officially leaving the company in 2021, Merino continued to operate the scam, which spanned 30 countries. Spanish authorities now have 15 to 40 days to submit extradition documents to the UAE. The scheme is also under investigation in the US and Mexico, with the US DEA estimating the scam's involvement at $100 billion. Merino has denied handling funds, blaming other team members, while the Spanish National Securities Market Commission has warned since 2021 that FX Winning was unauthorized to offer investment services.