New York City had 88,830 vacant rent-stabilized apartments in 2021, according to figures from the city's Department of Housing Preservation and Development, nearly 30,000 more than previously disclosed figures from New York state, The City reports.

The city has approximately 1 million rent-stabilized units, according to HPD data, meaning that almost 1 in 10 rent-stabilized apartments was vacant last year.

HPD’s total tally includes almost 43,000 units that the agency’s report considers “unavailable,” Chief Research Officer Lyz Gaumer told The City, in addition to tens of thousands designated as “available for rent” by the Census Bureau. She added the figures are “a very conservative estimate of the entire warehoused apartment universe.”

The total number includes apartments on the market, in addition to livable apartments that landlords are keeping off the market, Gaumer said.

The state’s numbers are based on information reported by property owners, which makes them less accurate than the city figures because HPD’s data collection includes phone calls and apartment visits made by Census Bureau representatives, HPD spokesperson Jeremy House told The City.

Between January 2020 and the following January, the state’s figures showed the number of vacant rent-stabilized apartments doubled to more than 61,000, The City previously reported. Landlords also registered tens of thousands fewer rent-stabilized units in 2021, potentially evading rent law enforcement and resulting in 95,000 rent-stabilized apartments lost after 2019.

New York requires the city to collect census data every three years to determine how many apartments are vacant. If the vacancy rate is less than 5%, the city has a “rent emergency” as defined by state law, meaning that rent stabilization laws must remain in place.

Jay Martin, executive director of landlord lobbying group Community Housing Improvement Program, previously told Bisnow that the 2019 tenant protection laws made renovations too expensive for small landlords, rendering apartments uninhabitable and inappropriate for rent.

Speaking to The City, Martin said HPD's numbers "should send off alarm bells to lawmakers that something is wrong and needs to be fixed immediately to get these units back online.”

Tenants in rent-stabilized buildings throughout NYC allege that landlords deliberately leave apartments vacant in an attempt to persuade the remaining tenants to leave.

Under some circumstances, a vacant rent-stabilized building can become deregulated, allowing landlords to charge new tenants market-rate rents. There have also been reports of landlords combining two vacant rent-stabilized units to make a larger market-rate unit and dodge the laws.

Landlord groups, including CHIP, have sued the state over the 2019 laws, claiming they violate a clause in the Fifth Amendment over illegal taking of property. Those groups are hoping the Supreme Court and its 6-3 conservative majority take up the case and overturn the new rules, potentially dealing a windfall to owners who have kept units vacant in the interm.