The trade group's Refinancing Index rose 0.8 percent from the previous week, a small gain, but enough to push it to a more than three-year high.
Refinancing also reached 81 percent of the total mortgage applications, the highest that has been since January.
In the week, interest rates for 30-year, fixed-rate conforming mortgages rose from 3.74 percent to 3.75 percent with points rising from 0.43 to 0.51.
The average interest rate for 15-year fixed-rate mortgages also rose, climbing from 3.07 percent to 3.09 percent, with points rising from 0.47 from 0.49 in the week.
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