A 5% U.S. mortgage rate is seen as tipping point to unlock supply

U.S. homeowners are nearly twice as willing to sell if their mortgage rate is 5% or higher, but just one in five mortgaged homes meet that criteria.

For those who have a mortgage rate of at least 5%, 38% said they're planning on selling their homes, according to a quarterly survey by Zillow. Just 21% of holders with rates below that dividing line said the same.

Existing-home sales have fallen almost every month since the start of last year as higher mortgage rates disincentivize owners from moving. Prospective buyers have sought out new construction instead since inventory on the resale market is so low.

About 80% of mortgage holders reported having a rate of less than 5%, and about 90% have a rate of less than 6%, Zillow said. Almost a third reported a rate of less than 3%.

Mortgage rates "are unlikely to return to 5% in the near future," said Orphe Divounguy, a senior economist at Zillow Home Loans. "That means many homeowners will move only for major life events, like a new baby or retirement."

Even so, nearly a quarter of homeowners are considering selling their home in the next three years or currently have their home listed for sale - significantly higher than the 15% of homeowners who said the same one year ago, Zillow said. That suggests inventory could be on the rise soon.

Of course, mortgage rates aren't the only factor that influence one's decision to move. About two-thirds said they're looking to upgrade to a nicer home while 45% cited a growing family.

The tight supply on the resale market has kept home prices elevated. Zillow's latest monthly market report finds that home values hit a record high in June, topping $350,000 for the first time nationally. And home values climbed in all of the 50 largest metro areas for a second month in a row.