Average fixed mortgage rates in the U.S. eased for a fifth straight week, with the 30-year fixed rate reaching the lowest level since late October, according to mortgage-finance company Freddie Mac (FMCC).

The latest decline in fixed mortgage rates came amid reports that existing home sales are up 1.3% but not as much as expected, Freddie Mac Chief Economist Frank Nothaft said in a statement Thursday. However, new home sales rose 6.4% in April, which followed an upward revision for the previous two months.

For the week ended Thursday, the 30-year fixed-rate mortgage averaged 4.12%, compared with 4.14% a week earlier and 3.81% a year earlier. Rates on 15-year fixed-rate mortgages averaged 3.21%, compared with 3.25% the previous week and 2.98% a year earlier.

Five-year Treasury-indexed hybrid adjustable-rate mortgages, or ARMs, on average, was at 2.96%, unchanged from the previous week and up from 2.66% a year earlier. One-year Treasury-indexed ARM rates on average were 2.41%, compared with 2.43% the previous week and 2.54% a year earlier.

Write to Tess Stynes at tess.stynes@wsj.com

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