[fl0ps]

Not a finance guy but I think that would literally be the opposite of how banks work. They have to lend out customers money in various forms, including giving that money to other customers in the form of loans, loaning it in huge chunks to companies for larger percentage rates than they give customers who keep their money in said bank, and so forth. Not sure how a bank that kept every customers money on hand all the time would work.

[lmm]

A "narrow bank" could work, but the Fed currently denies them banking licenses, since (presumably) the social function of banks lending out deposits is considered useful.

[ericd]

Well, there are banks that charge you money to hold onto your cash for you.