Landlords late to register tens of thousands of rent-stabilized apartments with New York state’s affordable housing agency could soon face a $500 fine for each month they’re tardy under a new law signed by Gov. Kathy Hochul.

The law could apply to owners of at least 46,000 apartments who failed to register their units by the end of the state’s most recent registration year, according to a report issued Tuesday by the state Division of Homes and Community Renewal’s Office of Rent Administration.

Jay Martin, executive director of the landlord trade group Community Housing Improvement Program, said the new fines would most likely hit property owners with smaller portfolios who handle their own bookkeeping and filing.

“We’re concerned on their behalf,” he said. “But people are going to file on time.”

Previously, owners who failed to register their apartments could not legally charge new price increases approved annually by the New York City Rent Guidelines Board.

Tenant advocates say the additional fines are important for penalizing owners who cheat the system by lifting units out of rent regulation or try to deceive tenants unaware their rents are supposed to be legally capped.

“If people go to see if their apartments are rent-regulated and they’re not registered, then if someone is uneducated [on the issue] they assume it’s not,” said Legal Aid Society attorney Ellen Davidson.

The newly released report shows registered units dropped from just under 945,000 during the 2022 state fiscal year to 898,789 in fiscal year 2023, which ran from April 1, 2022 to March 31, 2023.

The dramatic decrease doesn’t mean those units went market-rate, nor that landlords are cheating rent regulations or keeping apartments off the market; it could be largely attributed to late filers. HCR said it now has registration paperwork for about 933,000 units and the number will likely rise.

Recent reports show owners typically fail to register tens of thousands of apartments on time every year. Last year’s report reflected a similar decrease of about 46,000 registered units, but most of them have been added to the updated total in this year’s report.

Still, thousands of apartments remain unaccounted for. Some units age out of rent regulations once certain property tax abatements end, while others are illegally deregulated.

The annual registration tally allows tenants to check the status of their apartments to help determine if they are being over-charged on rent.

NYC’s most recent housing survey counted just over 1 million rent-stabilized units in the five boroughs. The state’s Office of Rent Administration also tracks registrations in Westchester, Rockland and Nassau counties.

Brooklyn accounted for the largest decrease in registered units, with about 17,500 fewer as of March 31, 2023 than in the previous year, the new report shows. There were about 10,500 fewer registrations in the Bronx and around 10,000 fewer in Manhattan.

While some tenant advocates say the new fines will enable the state to better enforce compliance, Cea Weaver, an organizer with the statewide Housing Justice for All Coalition, says enforcement has historically lagged.

Relatively few tenants make complaints, and when they do, HCR has struggled to respond in a timely manner — though the agency has processed a rising number of overcharge claims and conducted more investigations over the past two years, per the report.

“There needs to be better enforcement of rent registration laws,” Weaver said. “Enforcement is basically a joke.”