CHINESE President Xi Jinping's mantra that homes should be for living in is falling on deaf ears, with tens of millions of apartments and houses standing empty across the country.
Soon-to-be-published research will show that roughly 22 per cent of China's urban housing stock is unoccupied, according to Gan Li, an academic who ran the main nationwide study. That adds up to more than 50 million empty homes, he said.
The nightmare scenario for policy makers is that owners of unoccupied dwellings rush to sell if cracks start appearing in the property market, causing prices to spiral.
The latest data, from a survey in 2017, also suggests Beijing's efforts to curb property speculation - considered by leaders a key threat to financial and social stability - are coming up short.
"There's no other single country with such a high vacancy rate," said Professor Gan of Chengdu's Southwestern University of Finance and Economics. "Should any crack emerge in the property market, the homes to be offloaded will hit China like a flood."
One solution that the government could use is property or vacancy taxes to try to counter the issue, but neither appears imminent and some researchers, including Prof Gan, say what actually counts as vacant could be tricky to determine.
Thousands of researchers fanned out across 363 counties last year as part of the China Household Finance Survey, which Prof Gan runs at the university.
The vacancy rate, which excludes homes yet to be sold by developers, was little changed from a 2013 reading of 22.4 per cent, he said, adding that he was finalising the data for its release. The 2013 study showed 49 million vacant homes, and Prof Gan puts that number now at "definitely more than 50 million units".
Housing speculation has bedevilled China's leaders for years, as some cities and provinces tightened buying restrictions only to see money flooding into other areas.
Rampant price gains also mean millions of people are shut out from the market, exacerbating inequality.
Mr Xi had said in October last year that "houses are built to be inhabited, not for speculation".
Holiday homes and the empty dwellings of migrants seeking work elsewhere account for some of the deserted properties, but purchases for investment are a key factor keeping the vacancy rate high, according to Prof Gan.
That's despite curbs across the country meant to discourage buying of multiple dwellings.
There's an economic cost to vacancies too because they're a drag on supply, which puts upward pressure on prices and crowds young buyers out of the market, according to Kaiji Chen, who co-authored a Federal Reserve Bank of St Louis working paper called "The Great Housing Boom of China".
Prof Gan believes the government plans to do its own, larger survey in the next year or two.
Alternative sources for estimates include State Grid Corp electricity data, which former senior official Chen Xiwen cited this year for a 13 per cent vacancy level in medium-to-large cities.
Last month, Qiu Baoxing, a former vice housing minister, said the rate is 10 to 20 per cent in Beijing, exceeding levels in countries with vacancy taxes.
One example of a vacant home is a villa on the outskirts of Shanghai that 27-year-old Natalie Feng's parents bought for her. The two-storey residence was meant to be a weekend escape for the family of three. In reality, it's empty most of the time, and Ms Feng says it's too much trouble to rent it out. "For every weekend we spend there, we need to drive for an hour first, and clean up for half a day," she explained.
She joked that she sometimes wishes her parents hadn't bought it for her in the first place. That's because any apartment she buys now would count as a second home, which means she'd have to make a bigger down payment. BLOOMBERG