Is not the SEC aware of these mysterious "USDTs?" I still don't really get what they are or how they come to be, and furthermore how they are used to manipul

Is not the SEC aware of these mysterious "USDTs?" I still don't really get what they are or how they come to be, and furthermore how they are used to manipulate price. It's like a guarantee that there is a cash representation right? Also, most federally-backed banks have but a fraction of all balances on hand.