Actually if you think about the balance sheet for banks "too much money" is a problem for them because deposits are liabilities not assets. The money belongs to

Actually if you think about the balance sheet for banks "too much money" is a problem for them because deposits are liabilities not assets. The money belongs to customers not the bank. The bank must pay back the customers on demand. That said, I think historically many banks can easily avoid the "too much money" problem by setting the interest they pay on deposits to be low, and maybe even negative.