Lynne Sladky, Associated Press
In this Wednesday, Sept. 24, 2014 photo, developer Michael Capponi, left, photographs a waterfront property he renovated, during a viewing for brokers, in Miami Beach, Fla. The property is listing for $5,900,000, has 5,600 square feet, with seven bedrooms and seven and one half bathrooms. Freddie Mac, the mortgage company, releases weekly mortgage rates on Thursday, Oct. 2, 2014.

WASHINGTON — A key long-term U.S. mortgage rate dipped this week, the second drop after a large increase two weeks ago.

Mortgage company Freddie Mac says the nationwide average for a 30-year loan slipped to 4.19 percent from 4.20 percent last week. The average for a 15-year mortgage, a popular choice for people who are refinancing, was unchanged at 3.36 percent.

The 30-year rate is down from 4.53 percent at the start of the year. Rates have fallen even though the Federal Reserve has been trimming its monthly bond purchases, which are intended to keep long-term borrowing rates low. The purchases are set to end next month.

Mortgage rates often follow the yield on the 10-year Treasury note. The 10-year traded at 2.41 percent Thursday morning, down sharply from 2.57 percent a week earlier.