Big Banks Trust First Republic With Their Money

Banking is a confidence trick. You put money in the bank today because you are confident you can take it out tomorrow; to you, a dollar that you have deposited in the bank is just as good — just as much money — as a dollar bill in your wallet. If you show up at the ATM at any time of day or night, you expect it to give you your dollars. But the bank doesn’t just put your dollars in a box and wait for you to take them out; the bank uses its depositors’ money to make loans or buy bonds, and just keeps a little bit around for people who need cash. If everyone asked for their money back tomorrow, the bank wouldn’t have it. But everyone is confident that, if they ask for their money back tomorrow, the bank will have it. So they mostly don’t ask for it, so when they do, the bank does have it. The widespread belief that banks have the money is what makes it true.

This is obvious stuff.1 Also obvious, and famous, is that it is an unstable equilibrium. If people stop believing it, it stops being true. If everyone stops believing in a bank, they will all rush to get their money out, and the bank won’t have it, and their lack of belief will be retrospectively justified. Whereas if they had kept believing, their belief would also have been justified.