Banks can also offer [[certificates of deposit]] where the money is tied up for a set length of time earning a set interest rate. Generally speaking, the longer the period of time the money is tied up, the greater the interest rate it will earn. | Banks can also offer [[certificates of deposit]] where the money is tied up for a set length of time earning a set interest rate. Generally speaking, the longer the period of time the money is tied up, the greater the interest rate it will earn. |