Mortgage interest rates dipped slightly this week, according to two rate surveys. Freddie Mac’s (FRE) weekly survey reported the average rate for a 30-year fixed-rate mortgage (FRM) was 5.07% with an average 0.7 point for the week ending Sept. 10, down 1bp from the previous week’s average of 5.08%. Last year, Freddie Mac reported the average rate was 5.93%. A separate survey of major US banks and thrifts, conducted by Bankrate.com, reported the average interest rate for a 30-year FRM also dropped 1bp, to 5.4% with an average 0.34 point. One year ago, Bankrate.com reported the average rate was 6.15%. Freddie Mac reported the average rate for a 15-year FRM was 4.50% with an average 0.7 point, down 4bps from a week ago when it was 4.54%. Bankrate.com said the average interest rate for a 15-year FRM was 4.75%, an increase of 1bp from last week. Interest rates on adjustable-rate mortgages (ARMs) also decreased this week. Freddie Mac said the average rate for a five-year Treasury-indexed hybrid ARM was 4.51% with an average 0.5 point, down from 4.59% last week. The one-year ARM rate was 4.64% with an average 0.6 point, down from 4.62% last week. Bankrate.com said the rate for a five-year ARM was 4.89%, down 5bps from last week. Low rates have encouraged mortgage applications to increase, Freddie Mac vice president and chief economist Frank Nothaft said. Prospective borrower interest, particularly among first-time homebuyers seeking to take advantage of the federal tax credit, brought the Federal Reserve to indicate in its latest Beige Book that economic activity may be stabilizing. Write to Austin Kilgore.