The rate spread calculator generates the spread between the Annual Percentage Rate (APR) and a survey-based estimate of APRs currently offered on prime mortgage loans of a comparable type utilizing the “Average Prime Offer Rates” fixed or adjustable table, action taken, amortization type, lock-in date, APR, fixed term (loan maturity) or variable term (initial fixed-rate period), and lien status. Rate spread is a calculated field and is NOT simply the APR on the loan application.
A batch rate spread calculator is also available to allow institutions to calculate the rate spread on multiple Loan Application Registers (LARs).
 Do not use the rate spread calculator to calculate the HOEPA status; they are two different fields which require two different calculations. See Help for more details.
 If the loan application date is before October 1, 2009 and the action taken date is before January 1, 2010, use the old calculator.
 APORs are calculated using data from a combination of Freddie Mac's Primary Mortgage Market Survey® and other data. As of January 1, 2016, Freddie Mac no longer publishes (PMMS) results for the 1 - year ARM product. For details about the sources used since then, see the table of mortgage rate survery data.