U.S. mortgage rates rose this week for a third week in a row, lifted by investors' expectations for faster economic growth, which has pushed up borrowing costs.

Mortgage giant Freddie Mac said Thursday that the rate on 30-year, fixed-rate mortgages rose to 4.15 percent this week from 4.04 percent. That is the highest since March. The rate on 15-year fixed-rate mortgages, which is popular with homeowners who are refinancing, rose to 3.62 percent, also the third straight increase.

Signs of faster economic growth have also lifted concerns that inflation may quicken and the Federal Reserve will raise short-term interest rates more quickly to keep price increases in check. That has driven up the yield on the 10-year Treasury note. Mortgage rates track the yield on the 10-year.

The rate on five-year adjustable-rate mortgages climbed to 3.52 percent this week, after a flat reading of 3.46 percent last week.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country between Monday and Wednesday each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates.

The fee on 30-year mortgages slipped to 0.5 point from 0.6 point last week. The fee on 15-year mortgages was unchanged 0.5 percent. And the fee on five-year adjustable home loans moved up to 0.4 percent from 0.3 point.