The number of underwater borrowers continues to fall, but that was about the only good news Zillow  had to report in its latest look at negative equity.
The company released Tuesday its Negative Equity Report  for the first quarter, revealing an estimated 9.7 million homeowners continue to owe more on their mortgage than their home is worth. That number, down from about 9.8 million in Q4 2013, represents about 18.8 percent of mortgage-paying Americans, according to Zillow.
Conservative estimates from the company call for a negative equity rate of 17 percent by this time next year as home value growth moderates.
While the continuing downward trend in underwater rates is a welcome sign of improvement in the housing sector, the company notes that the "effective" negative equity rate, which includes homeowners with 20 percent or less equity in their homes, remains elevated at more than one in three.
"The unfortunate reality is that housing markets look to be swimming with underwater borrowers for years to come," said Zillow's chief economist, Dr. Stan Humphries.
With so many borrowers lacking enough equity to comfortably sell their homes and afford a down payment on a new one, Humphries expects inventory to remain choked, driving home values higher and making affordability a greater concern.
What's more, Zillow found that homes priced in the bottom third of home values nationwide have a greater negative equity rate, with 30.2 percent of that population currently underwater compared to 18.1 percent of those in the middle tier and just 10.7 percent in the top tier.
For those underwater borrowers who happen to be in the lower tier of home values, listing their home will remain difficult without engaging in a short sale or bringing cash to the closing table—another contributor to the supply shortage and a major obstacle for buyers in search of starter homes.
"It's hard to overstate just how much of a drag on the housing market negative equity really is, especially at the lower end of the market, which represents those homes typically most affordable for first-time buyers," Humphries said.