5.8
In fractional-reserve banking, banks hold a portion of their deposits as reserves and lend the rest.
Recall the hypothetical economy where Bank A lent $90 out of its $100 deposits. Bank B keeps nine dollars as reserves and lends out eighty-one dollars of new loans.
This process of lending and redepositing continues across multiple banks.
In our example, the reserve-deposit ratio is ten percent.
The formula to calculate the change in the total money supply is:
Initial change in reserves × (1 / reserve-deposit ratio). The initial change in reserves represents a new injection of reserves into the banking system.
In this case, the initial change in reserves is $100, and the reserve-deposit ratio is ten percent. So, the change in the total money supply is $1,000. The expression, 1 divided by the reserve-deposit ratio, is known as the simple money multiplier. It tells us the maximum amount the money supply can increase for each dollar of new reserves.
Fractional-reserve banking is a system in which banks are required to hold only a portion of their deposits as reserves, while the rest can be loaned…
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