Real-estate website Zillow Inc. (Z) said its real-time rate on 30-year fixed-rate mortgages fell in the latest week, recording the biggest weekly decline since January.

The 30-year fixed-mortgage rate on Zillow's Mortgage Marketplace, which tracks mortgages on the company's website, decreased to 3.96% in the latest week, down from 4.08% a week earlier.

"Mortgage rates stayed below 4% for much of last week on news of a potential European Central Bank plan to implement a stimulus program similar to the Federal Reserve's that has kept rates low in the U.S.," said Erin Lantz, vice president of mortgages at Zillow. "We expect rates to remain flat in this holiday-shortened week, as any bright spots in domestic economic data will likely be overshadowed by concerns about the European economy."

Zillow said the rate for a 15-year fixed home loan was 3.04%, compared with 3.15% the previous week. The rate for a 5-1 adjustable-rate mortgage was 2.81%, compared with 2.92%. A 5-1 ARM has an initial rate that applies for the first five years of the loan and then adjusts annually.

Zillow's real-time mortgage rates are based on thousands of custom mortgage quotes submitted daily to anonymous borrowers through the company's website.