That is what they DO!!
that is what the prime rate pertains to
He mentioned it like it was charity, something the do out of the goodness of their hearts.
It is called the "reserve requirement" set by the "reserve ratio"
http://en.wikipedia.org/wiki/Reserve_requirementThe reserve requirement (or required reserve ratio) is a bank regulation that sets the minimum reserves each bank must hold to customer deposits and notes. These reserves are designed to satisfy withdrawal demands, and would normally be in the form of fiat currency stored in a bank vault (vault cash), or with a central bank.
The reserve ratio is sometimes used as a tool in the monetary policy, influencing the country's economy, borrowing, and interest rates.<2> Western central banks rarely alter the reserve requirements because it would cause immediate liquidity problems for banks with low excess reserves; they prefer to use open market operations to implement their monetary policy. The People's Bank of China does use changes in reserve requirements as an inflation-fighting tool,<3> and raised the reserve requirement nine times in 2007. As of 2006 the required reserve ratio in the United States was 10% on transaction deposits (component of money supply "M1"), and zero on time deposits and all other deposits.