421-a apartments and rent stabilization

Many NYC rental buildings built since 1974 are rent stabilized only because the owner took a 421-a or J-51 property tax break, and accepting the benefit puts some or all of the apartments under rent stabilization. What happens when the tax break ends depends on when construction started, whether your unit is income-restricted, and whether every lease you signed carried a written deregulation notice.

Why a tax break makes an apartment stabilized

Rent stabilization usually covers buildings with six or more apartments built before 1974. Newer buildings are normally outside the system. But the 421-a and J-51 programs attach rent stabilization to the tax benefit: an owner who wants the tax break has to accept rent stabilization for some or all apartments, usually for a set period.

That gives you the same core rights as any stabilized tenant while your unit is covered:

• a renewal lease at your choice of one or two years;
• increases limited to the Rent Guidelines Board guideline (0% for leases starting October 1, 2026 through September 30, 2027);
• a lease rider explaining your rights, and, in 421-a buildings, the approximate date the benefit expires; and
• eviction only on grounds the law allows.

The versions of 421-a

421-a has been renewed and rewritten many times, so the rules depend on when construction of your building started. The two big families are 421-a(1-15), for buildings that started construction through December 31, 2015, and 421-a(16), also called Affordable New York, for buildings that started after December 31, 2015 and on or before June 15, 2022. Each 421-a building may have two kinds of units: income-restricted (“affordable”) units, which you had to income-qualify for, and market-rate units.

What happens when the 421-a benefit ends

Buildings that started construction after June 15, 2022 fall under 421-a’s replacement, the 485-x program (Affordable Neighborhoods for New Yorkers). HCR says its affordable units are permanently affordable and rent stabilized, except that in small projects of 6 to 10 units at least half the units must be permanently rent stabilized.

HCR’s example

A three-unit building got 421-a(1-15) benefits from April 1, 2014 to March 31, 2024. A tenant moved in on June 1, 2023 with a two-year lease that included the required notice and expiration date. When that lease came up on June 1, 2025, the apartment was deregulated and the owner could charge a market rent. Without the notice, the tenant would have stayed stabilized.

J-51: the rehab program

J-51 gives tax benefits to owners who rehabilitate building systems such as boilers, windows, plumbing, wiring and roofs. HCR says the benefit period often lasts about 12 years. There are two versions:

• Older buildings already stabilized (pre-1974, six or more units): the J-51 benefit doesn’t change anything. The apartments stay stabilized during and after the benefit.
• Buildings stabilized only because of J-51 (built or gut-renovated since 1974, or fewer than six units) for work completed before June 30, 2022: the same 12-point notice rule applies. With the notice in every lease, the apartment deregulates at the end of the last lease signed during the benefit period. Without it, the apartment stays stabilized until the tenant moves out.
• J-51 R (work completed on or after June 30, 2022): only certain units must be stabilized, for at least 15 years from the first benefit (or longer if HPD requires). The tenant in place at the end of that period stays stabilized until they move out.

HCR’s J-51 example: a four-unit building got J-51 benefits from January 1, 2013 through December 31, 2024. A tenant moved in March 1, 2022 and renewed March 1, 2024, and neither lease had the notice. At the March 1, 2025 renewal, the apartment stayed stabilized even though the benefit had expired.

The 2.2% surcharge during the phase-out

In some 421-a(1-15) buildings with benefits of 10 or more years, the owner can add a yearly 2.2% surcharge to certain units while the tax exemption phases down, if the tenant signed a “2.2% lease rider” offered by the owner. The surcharge is not allowed on 421-a(16) units or on many income-restricted units. If you see a 2.2% line on your renewal, check that you signed that rider and that your unit type is eligible.

How to check your building

1. 1

   Look up the building on Roofy

   Search the address on Roofy’s building lookup. The building page shows the year built, number of units and whether the building appears in rent-stabilization records. A building built after 1974 that appears there may be stabilized because of a tax benefit.
2. 2

   Check NYC Department of Finance records

   DOF’s 421a Partial Tax Exemption page publishes yearly lists of properties receiving 421-a, by borough, block and lot, as PDF and Excel files, plus a combined data file. Search for your building’s address or BBL in the current year’s list.
3. 3

   Find the construction start date

   HPD says the building’s 421-a certificate of eligibility, filed with DOF, lists the construction commencement date. That date decides which row of the table above applies.
4. 4

   Find out if your unit is income-restricted

   If you had to show household income to get the apartment, it is likely a 421-a affordable unit. HCR’s annual rent registration also identifies these units: request your rent history.
5. 5

   Read every lease rider

   Look for the 12-point deregulation notice and the approximate expiration date in your first lease and every renewal.
6. 6

   Estimate the timeline

   Use the 421-a and J-51 expiry calculator to see when the benefit ends and how the building’s taxes change.

If something looks wrong

• DOF shows a 421-a benefit, but you don’t have a rent-stabilized lease: HPD asks tenants to contact its Compliance & Enforcement unit. General 421-a questions go to [email protected].
• You think the owner deregulated you illegally or your riders are wrong: file a complaint with HCR’s Office of Rent Administration. See rent overcharge complaints.
• You are facing eviction: HPD points tenants to the Mayor’s Office to Protect Tenants, and many tenants qualify for a free lawyer through Right to Counsel.

Your apartment can also be stabilized for more than one reason, for example an older building that also received J-51. This guide is general information, not legal advice; HPD and HCR both say to check the specific law and your leases, and to consult a lawyer for your situation.