[samatman]

Either fractional reserve banking itself is ridiculous, or a 0% net balance is the right number.

If withdrawals get out ahead of collections on debts held by the bank, FISA can (will) step in and make the withdrawing parties whole. The bank now owes FISA and can repay at leisure. This works even if the bank experiences a run, FISA has a bottomless wallet.

If credit issued exceeds 100% of "held" assets, that's clearly fraudulent, it will never work out. But compelling banks to hold some arbitrary amount of the leverage is pointless.

The bank is of course in trouble if defaults exceed the interest on loans, but that was already the case. A 0% balance surfaces this problem faster, and again, FISA pays out, acquires the outstanding debts in lieu of full repayment, and the bank goes bankrupt. No big deal.