Owners of homes at the bottom of the market are trapped underwater on their mortgages even as the real estate market continues to recover, according to the fourth quarter Negative Equity Report from Zillow Group (Z).

That’s because low-end homes – the most likely to be upside-down – are losing value.

This seems to contradict the findings of CoreLogic (CLGX), which recently said in its most recent report that nationwide, borrower equity increased year over year by $656 billion in 4Q14. The CoreLogic analysis also indicates approximately 172,000 U.S. homes slipped into negative equity in the fourth quarter of 2014 from the third quarter 2014, increasing the total number of mortgaged residential properties with negative equity to 5.4 million, or 10.8% of all mortgaged properties.

This compares to 5.2 million homes, or 10.4%, that were reported with negative equity in third quarter 2014, a quarter-over-quarter increase of 3.3%. Compared to 6.6 million homes, or 13.4%, reported for Q4 2013, the number of underwater homes has decreased year over year by 1.2 million or 18.9%.

Zillow, however, found that while foreclosures, short sales and rapidly rising home values freed nearly half of those homeowners, but now that trend has reversed in many metros. Three years into the recovery, home values overall continued to recover while owners of the lowest-valued homes – those most likely to be stuck in negative equity – were left behind.

“Higher negative equity rates have become the new normal,” said Zillow Chief Economist Stan Humphries. “We’ve long been expecting the negative equity rate to fall more slowly as home value growth also slows, and unfortunately that’s exactly what we’re seeing. Compounding the problem is the fact that negative equity is decidedly not an equal opportunity predator, and looms larger over the bottom 10% of homes, where homeowners are least prepared to withstand the assault.”

In the fourth quarter of 2014, the negative equity rate worsened in 21 of the top 50 U.S. markets.

Nationally, home values rose around 6% in 2014.

Less valuable homes are much more likely to be underwater.

For example, in Atlanta, 49% of homes in the bottom-third of home values are in negative equity, compared to 11% of mortgaged homes in the highest valued third.

Nationally, 16.9% of all homes with a mortgage are in negative equity, and that is expected to fall to 15.4% by the end of 2015. Among large metros, Virginia Beach (28.3%), Jacksonville (27.0%), Las Vegas (26.4%), and Atlanta (26.1%) had the highest rates of negative equity.