15-year mortgage rate falls below 4 percent

Fixed mortgage rates tumbled this week and the 15-year mortgage rate dipped below 4 percent for the first time in three months. Rates followed the yield on U.S. Treasury bonds, which fell on worries that the crisis in Japan could slow economic growth.

Freddie Mac said Tuesday the average rate on the 15-year fixed mortgage, a popular refinance option, dropped to 3.97 percent from 4.15 percent. The last time the rate was below 4 percent was in mid-December. It reached 3.57 percent in November, the lowest level on records dating back to 1991.

The average rate on the 30-year fixed mortgage fell to 4.76 percent from 4.88 percent the previous week. It hit a 40-year low of 4.17 percent in November.

Mortgage rates tend to track the yield on the 10-year Treasury note. Those yields have tumbled as investors sought safer investments.

Low mortgage rates haven't been enough to jumpstart the housing market. Home construction last month plunged to its lowest level in almost two years, while building permits, an indicator of future housing activity, sank to a five-decade low, the government said this week.

Homebuilders remain pessimistic about the outlook for housing. High unemployment, a record number of foreclosures and tough credit standards have kept many people from buying homes. And most economists don't expect home values to bottom out until midyear, another factor dissuading potential homebuyers.

To calculate average mortgage rates, Freddie Mac collects rates from lenders across the country on Monday through Wednesday of each week. Rates often fluctuate significantly, even within a single day.

The average rate on a five-year adjustable-rate mortgage fell to 3.57 percent from 3.73 percent. The five-year hit 3.25 percent last month, the lowest rate on records dating back to January 2005.

The average rate on one-year adjustable-rate home loans slipped to 3.17 percent from 3.21 percent. That is the lowest level in a year for the one-year ARM rate.

The rates do not include add-on fees, known as points. One point is equal to 1 percent of the total loan amount. The average fee for the 30-year fixed loan and 15-year fixed loan in Freddie Mac's survey was 0.7 point. The average fee for the five-year ARM and the 1-year ARM was 0.6 point.