The average interest rate on a 30-year fixed-rate mortgage was 4.46% in October, a drop of 12 basis points from September when the rate was 4.58%, according to the Federal Housing Finance Agency. The FHFA calculates the average monthly rates for more than 4,252 loans closed by 31 lenders between Oct. 25 and Oct. 29. On those transactions, the interest rate is determined 30 to 45 days before the loan is closed. The FHFA’s index for the average rate on the purchase of previously owned homes fell 6 bps to 4.49% for the month, another new low since 1980 when mortgage rates were as high as 15%. The average interest rate on a 15-year fixed-rate mortgage decreased substantially, down 33 bps to 4.24%. The contract rate on the composite of all mortgage loans, both adjustable-rate mortgages and FRMs, fell to 4.44% from 4.52% the month before. Write to Christine Ricciardi.