Why would banks borrow at the Fed's discount window, anyway? The Federal Reserve also requires that banks have a certain amount of cash on hand each night, known as the reserve requirement. To maintain bank solvency, the Fed does not want banks to loan 100% of their money. However, the Fed realizes that sometimes banks loan out too much that day. Therefore, it allows them to borrow from the discount window to make sure they have enough for their reserve requirement.

