I’m well aware of how banks work. See my second to last sentence in which I describe how the price of storing money in a bank is set and why it can be negative.

I’m well aware of how banks work. See my second to last sentence in which I describe how the price of storing money in a bank is set and why it can be negative. Banks are definitely storing money. They’re just not storing physical currency. They mostly store money in various financial instruments such as loans, which provides them with some revenue. If that revenue is sufficiently high, they can make all their money this way and set a negative price for their money storage services. But there’s no natural law that says the revenue potential must be that high.