It's unlikely that some sort of local or national emergency would cause a bank run, but it is possible given the surprising low cash reserves banks are required to maintain. (treesfullofmoney.com)
Let's assume we have a fractional reserve banking system in which banks face a 10 percent reserve requirement. (alt-m.org)
It's the way in which you can turn the fractional reserve banking system in your favor. (insuranceandestates.com)