If you read further down, it seems to show that the banking system as a whole can expand $100 into $1000 with a 10% reserve requirement: "Reserve requirements

If you read further down, it seems to show that the banking system as a whole can expand $100 into $1000 with a 10% reserve requirement: "Reserve requirements affect the potential of the banking system to create transaction deposits. If the reserve requirement is 10%, for example, a bank that receives a $100 deposit may lend out $90 of that deposit. If the borrower then writes a check to someone who deposits the $90, the bank receiving that deposit can lend out $81. As the process continues, the banking system can expand the change in excess reserves of $90 into a maximum of $1,000 of money ($100+$90+81+$72.90+...=$1,000), e.g.$100/0.10=$1,000." - from http://en.wikipedia.org/wiki/Reserve_requirement http://en.wikipedia.org/wiki/Reserve_requirement