More Chinese homeowners have opted to leave houses empty rather than sell, a symptom of a cooling housing market that once buoyed China’s impressive growth.

China’s home vacancy rate was 22.4 percent last year, up from 20.6 percent in 2011, according to a survey from China’s Southwestern University of Finance and Economics. Builders who sought their fortune in a housing boom are now concerned about inventories, and these empty homes are more vulnerable to a cooling market.

“Vacant homes are more likely to cause losses and push owners into negative equity once home prices fall,” said Gan Li, head of the China Household Finance Survey and Research Centre, to the South China Morning Post.

Both analysts and investors are concerned about uninhabited apartments in so many Chinese cities, a result of the authorities’ desire for fast growth fueled by easy credit. In the past few years the home market has been a popular investment, but lately prices have stagnated as China’s authorities allowed investment in other sectors, the Wall Street Journal reports.

Roughly 49 million sold residential homes in China are sitting empty, and more than $674.33 billion worth of Chinese mortgage loans are outstanding. Some homes are left vacant by people who own many, while other owners simply moved to other cities and didn’t sell as the housing market corrects itself.

Chinese home prices will likely fall 5 percent this year, after an 11.5 percent increase in 2013, predicted analysts from Standard & Poor’s.

“Prices are likely to continue to slide because of large inventory in some markets,” their analysts wrote in a report, according to Bloomberg.

“Many small unrated developers will feel the heat the most because their sales and financing capabilities are substantially weaker than their larger peers.”

The report’s researchers surveyed households in 262 counties in 29 provinces.