Mortgage rates' rise has led to wide gap with US bond yields

LOS ANGELES (AP) — Economists are baffled by a wider-than-usual divergence between long-term mortgage rates and the yield on the benchmark U.S. government bond that is driving a sharp rise in borrowing costs and helping to torpedo the U.S. housing market this year.

The gap, or spread, between the 10-year Treasury yield and the average rate on a 30-year mortgage widened this year as inflation hit the highest level in decades and the Fed began raising interest rates and taking other steps aimed at taming surging prices.

This spread has historically averaged around 170 basis points a month, but between March and October it averaged about 240 basis points, according to Federal Reserve data. In October, the spread widened to 292 points, the biggest monthly gap since August 1986.

“The spread between the 10-year Treasury and the mortgage rate is exceptionally wide, abnormal,” Lawrence Yun, chief economist for the National Association of Realtors said last week. “If we had a narrowing, or say, a normal spread condition, today’s mortgage rate could be 5.7%.”

Mike Fratantoni, chief economist at the Mortgage Bankers Association, agreed: “One of the more puzzling aspects of the current environment has been the extremely wide spread of mortgage rates relative to Treasury rates."

Rates for 30-year mortgages usually track the moves in the 10-year Treasury yield, which lenders use as a guide to pricing loans. Investors’ expectations for future inflation, global demand for U.S. Treasurys and what the Federal Reserve does with interest rates can also influence the cost of borrowing for a home.

In the first week of January, when the 10-year Treasury yield averaged 1.77% and the rate on a 30-year mortgage averaged 3.22%, the spread was 145 basis points.

In the months that followed, as...