In the EU at least there's directive 94/19/EC[1] which I believe stipulates that deposit-guarantee schemes have to be in place in all EU countries that protect customers from losing their money in the event that a bank goes bankrupt or withholds their money. Is there something similar in the US?
[1]: https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL...