Average fixed-mortgage rates in the U.S. fell in the latest week, according to mortgage-finance company Freddie Mac (FMCC).

Freddie Mac Deputy Chief Economist Len Kiefer said Thursday that the drop in fixed mortgage rates followed a decline in 10-year Treasury yields.

For the week ended Thursday, the 30-year fixed-rate mortgage rate averaged 3.69%, compared with 3.78% a week earlier and 4.4% a year earlier. Rates on 15-year fixed-rate mortgages averaged 2.97%, compared with 3.06% the previous week and 3.42% a year earlier.

Five-year Treasury-indexed hybrid adjustable-rate mortgages, or ARMs, on average, were at 2.92%, compared with 2.97% the previous week and 3.1% a year earlier. One-year Treasury-indexed ARM rates on average were at 2.46%, unchanged from last week and up from 2.44% a year ago.

Write to Chelsey Dulaney at chelsey.dulaney@wsj.com

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