The multiplier effect is the relationship between the reserves in a bank and the money supply. The level of prices and the value of money 2.Calculate the money supply, the currency deposit ratio, the excess reserve ratio, and the money multiplier. b. The money multiplier determines the limit of how much money a bank can create. The multiplier effect refers to the proportional amount of increase, or decrease, in final income that results from an injection, or withdrawal, of capital.