APY, or Annual Percentage Yield, tells you the return you will receive on a deposit over a one-year period based on the interest rate and interest compounding frequency. Interest Rate is the annualized rate applied to the principal balance of the account each day in order to determine the amount of interest that has accrued on that day’s principal balance. Annual Percentage Yield (APY) reflects the effect of compounding frequency (Savings accounts are compounded daily) on the interest rate over a 365-day period, or (366-days in the event of a leap year).