The average mortgage rate for conventional mortgages remained unchanged in May, according to the latest monthly rate report by the Federal Housing Finance Agency (FHFA). In its report (download here), the FHFA said the average interest rate for a conventional, 30-year fixed-rate purchase mortgage with a principal of $417,000 or less was 5.12% in May, even from last month's report. As seen in the chart above, rates are nearly level with the November 2009 average. The average rate for 15-year fixed-rate purchase mortgages of $417,000 or less was 4.58%, up from 4.52% in April. The average rate for all mortgage types — fixed- and adjustable-rate — was 4.99% in May, down from 5.02% in April. The effective rate, which includes the amortization of initial fees and charges, was 5.1% in May, down from 5.12% in April. The rates are calculated from the FHFA's monthly interest rate survey (MIRS) of purchase mortgages. It reflects loans that closed from May 24-31. Typically, interest rates are determined 30 to 45 days prior to closing, so the survey reports market rates in mid-to-late April. FHFA said initial fees and charges were 0.72% of loan balances in May, up from .063% in April. The share of no-point purchase mortgages was 42% in May, down from 45% in April. The average term for loans was 27.5 years in May down from 27.6 years in April. The average loan to value ratio was 74.1% in May, down 0.2% from 74.3% in April. The average mortgage principal was $218,600 in May, down $200 from $212,800 in April. In a separate report, the FHFA said the average contract mortgage rate for the purchase of previously occupied homes by combined lenders was 4.99% based on loans that closed in May, down from 5.02% in April. This rate is commonly used as an index in ARM contracts. Write to Austin Kilgore.