What does that mean? You think someone is physically wheelbarrowing something around between banks when you make a transfer? The banks settle up at the end of day and the net amount moved between banks is far smaller than the total transferred. What do they settle up in? Another layer of electronic funds you don't have access to.
If even the smart people on HN can't understand this it's little wonder the finance industry has such a stranglehold on society. The banks just run a ledger. That's all they are doing. But it's a ledger they control and they are allowed to create new money in it. In fact 97% of money is created by the banks when they issue loans.
It's a fundamentally different model to the antiquated "banks lend out your deposits" one.