Personally, I think it's folly to describe it as cash in the bank. It's a deposit with the bank, and deposits are only 1-3% cash backed and the rest is backed by loans of some sort. Even a bank as big as CBA would have trouble producing $500m cash on short notice; BOQ certainly doesn't have the firepower to accomodate a $500m cash withdrawal - without another recapitalisation/bailout.