The Federal Reserve‘s plan to reinvest principal payments on some bonds into mortgage-backed securities is already contributing to the nation’s record low mortgage interest rates, Bankrate said Thursday. Bankrate said the Federal Open Market Committee seems to be taking direct aim at mortgage rates by shifting $400 billion from short-term holdings into long-term government bonds. The program, which begins Oct. 3 and runs through June, will involve longer-term Treasury securities with remaining maturities of six years to 30 years, and will be financed through the sale of shorter-term Treasurys with maturities of three years or less. “This program should put downward pressure on longer-term interest rates and help make broader financial conditions more accommodative,” the FOMC said in a statement following its two-day meeting. Analysts also said anemic economic growth and European debt fears are keeping investors on the sidelines. Rates are unlikely to increase until mortgage refinancing and purchasing activity picks up, Bankrate said. “In order to get the most economic impact out of low mortgage rates, the pool of prospective refinancers needs to be expanded. Deeply upside-down homeowners, those with second liens or mortgage insurance, and lender concerns about buyback liability are all formidable impediments to refinancing,” according to the firm, which aggregates rate data from across the country. The Freddie Mac primary mortgage market survey showed the average rate for a 30-year, fixed-rate mortgage remained unchanged this week at 4.09%, while the 15-year, fixed rate dropped one basis point to a new record low of 3.29%. Meanwhile, the five-year, Treasury-indexed hybrid adjustable-rate mortgage averaged 3.02%, up from 2.99% last week and down from 3.54% a year ago. The one-year, Treasury-indexed ARM averaged 2.82% this week, up from 2.81% a week earlier and down from 3.46% last year. “A sluggish economy and investor concerns over the European debt markets left mortgage rates largely unchanged this week,” said Frank Nothaft, vice president and chief economist for Freddie Mac. “Manufacturing activity in both the New York and Philadelphia regions contracted in September,” he said. “Moreover, the Federal Reserve board reported that households lost nearly $150 billion in net worth in the second quarter, representing the first quarterly decline in a year.” Bankrate data show the 30-year FRM at record lows for the fifth consecutive week. The average rate for a traditional mortgage fell to 4.29%, from 4.32% last week, while the 15-year FRM declined to 3.42% from 3.44%. In addition, the 5/1 ARM decreased to 3.05% from 3.07% last week. Write to Kerri Panchuk.