(Bloomberg) -- New York City and Chicago are home to some of the most vulnerable housing markets in the U.S., where the pandemic continues to threaten homeowners and the broader economy.

Of the 50 most at-risk counties across the country, those two metropolitan areas each had eight, while there were seven throughout California in the final three months of 2021, according to real estate data firm Attom Data Solutions. The Philadelphia area and Delaware also had a cluster of vulnerable counties, Attom said.

The markets represent areas where housing is unaffordable for average workers, higher levels of foreclosures and larger portions of homeowners who are underwater on their mortgages, which means one’s mortgage balance exceeds the estimated property value. Home valuations have surged during the pandemic, and more recently, mortgage rates are on the rise as well.

“The virus remains a potent threat to the broader economy and the housing market,” said Todd Teta, chief product officer at Attom. “No immediate warning signs hang over any one part of the country, but pockets are more vulnerable to the market taking a turn for the worse.”

Of the 10 most at-risk counties -- including New Jersey’s Sussex, Passaic and Essex -- Attom found that on average, one spends between 32% and 45% of their income on housing. The median home price of the top 10 ranged from $212,001 to $480,000.

In Sussex in particular -- ranked the most vulnerable -- one of every 709 homes is in foreclosure. By that measure, only Cuyahoga County near Cleveland, Ohio, Saint Clair County near St. Louis and New Jersey’s Camden County are worse.

Outside of California, housing in the West had the highest concentration of markets considered least vulnerable to pandemic-related damage.

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