AFAIK there are no FDIC insured stable coins - there's apparently USDF[1] which is being promoted by FDIC insured banks but the coins themselves aren't subject to FDIC insuring and could quite possibly either bankrupt the backing entity or be abandoned in the case of a bank run.

Which stablecoins were you talking about?

1. https://www.coindesk.com/markets/2022/01/13/fdic-still-uncle...