“It’s not a stablecoin, it’s a high-risk offshore hedge fund,” said John Betts, who ran a bank in Puerto Rico Tether used. “Even their own banking partners don’t know the extent of their holdings, or if they exist.”

https://www.bloomberg.com/news/features/2021-10-07/crypto-mystery-where-s-the-69-billion-backing-the-stablecoin-tether?sref=EcccZSTc