The Banking system normally only keeps a few billion in actual cash on hand. The rest is lent to other banks for short term, overnight needs.
Due to the panic banks are hording cash and not lending it out to others. As of last week it was approx $90 Billion. That is why the Fed put in $180 billion in intrabank liguidity last week. It was done to give banks confidence that they didn’t have to horde money.
