The 421-a Expiration Wave
The tax calendar is becoming a comparable.
An estimated 54,390 condominium and co-operative apartments in 3,610 buildings sit at properties reaching first full taxation from fiscal years 2023 through 2040. The expiration wave is already underway, it arrives in two distinct phases, and the resale record suggests that buyers may begin responding before the benefit finally ends.
By Corey Cohen, Principal of The Roebling Team at Compass and publisher of The Roebling Index
September 2026
- The wave is large and already underway. Recorded 421-a benefit periods at 3,610 condominium and co-operative buildings, containing an estimated 54,390 apartments, reached or are scheduled to reach first full taxation during FY2023–FY2040.
- It arrives in two waves. Approximately half of the affected apartments fall in FY2023–FY2030. A second wave builds after FY2032 and peaks in FY2035.
- The exposure is geographically uneven. Brooklyn and Queens carry most of the buildings. Manhattan’s exposure is concentrated in fewer, considerably larger properties.
- The resale record contains a pricing signal. Two descriptive comparisons show weaker performance among properties at or near expiration. They do not establish causation, but the differences are large enough to matter in valuation and negotiation.
The practical conclusion is straightforward: the expiration year belongs in a valuation alongside square footage, maintenance or common charges, reserve condition and the building’s capital plan.
An apartment and a tax calendar
421-a reduced the property tax attributable to qualifying new residential construction for a fixed period. Depending on the program and property, the benefit ran for a stated term and often phased down before the property became fully taxable.
That created a second clock inside every transaction. The closing price reflected the apartment, but the monthly carrying cost also reflected where the property sat on its benefit schedule. Two otherwise similar apartments were not economically identical if one had twelve years of benefit remaining and the other had two.
The expiration wave is the point at which that clock becomes visible. Buyers begin underwriting the later tax bill before it appears. Sellers confront a shorter remaining benefit. Boards must explain a change that is scheduled rather than unexpected.
Condominium and co-operative are Department of Finance property classifications, not statements of occupancy. Condominiums may be investor-owned and rented; co-operative residents own shares and a proprietary lease. The apartment count in this analysis is an estimate at the property-group level, not an occupancy census.
The clock is striking in two waves
The first wave runs at roughly 4,000 condominium and co-operative apartments a year through FY2028. FY2029–FY2032 form a brief trough. The second wave then rises sharply, reaching 6,322 apartments in FY2035.
| First fully taxable period | Condominium and co-operative apartments |
|---|---|
| FY2023–FY2030 | 26,770 |
| FY2031–FY2040 | 27,620 |
| Total | 54,390 |
This is not one event and it is not one kind of building. The calendar extends from small outer-borough condominiums to large Manhattan towers, with materially different consequences across submarkets.
Brooklyn and Queens carry the buildings. Manhattan carries the concentration.
| Borough | Buildings | Apartments |
|---|---|---|
| Brooklyn | 2,350 | 25,868 |
| Queens | 639 | 13,760 |
| Manhattan | 208 | 12,604 |
| Bronx | 350 | 1,902 |
| Staten Island | 63 | 256 |
| Total | 3,610 | 54,390 |
Brooklyn accounts for 2,350 affected buildings and almost half of the condominium and co-operative apartments in the cohort. Queens adds another 639 buildings. Much of that exposure is distributed across smaller properties in entry-price markets including Flushing, Sheepshead Bay, Gravesend and Woodside.
Manhattan presents the inverse pattern: only 208 buildings, but 12,604 apartments. Its exposure is concentrated in a smaller number of large towers, so the significance is less about building count than the capital value and transaction volume contained inside each property.
The same monthly tax increase also carries different weight across submarkets. In a lower-price apartment, it can represent a larger share of total carrying cost and buyer affordability. In a high-value tower, the percentage may be smaller while the absolute value at risk is larger.
The last tax bill is not the first market signal
Most benefit schedules do not move from fully exempt to fully taxable in a single step. They phase down over time, allowing buyers to respond to the terminal cost before the first fully taxable year.
The Oro at 306 Gold Street provides a recorded example. Department of Finance data show a FY2011 benefit start and a 15-year term, making FY2026 the first fully taxable year. The applicable schedule reduces the exemption from 100 percent to 80, 60, 40 and 20 percent during FY2022–FY2025 before it reaches zero.
That schedule is not the apartment’s tax bill. The actual amount depends on assessed value, the taxable share of the property and whether the individual owner qualifies for a separate co-op/condo abatement. The underwriting question is therefore not simply what the apartment pays today. It is the full path from the current bill to the first fully taxable year.
If future taxes matter, prices should move before taxes do
Administrative records establish the scale and timing of the wave. Transactions address the harder question: whether the approaching end of the benefit is visible in price.
No public dataset can isolate a tax schedule from building quality, interest rates, neighborhood supply, renovation and seller circumstances. The evidence must therefore be read as association, not proof of cause. This analysis uses two comparisons at different resolutions.
The market-wide comparison
The first test covers 37,029 recorded condominium sales across 841 tax blocks. It compares the two ends of the benefit calendar:
- 142 blocks where benefits end by FY2028;
- 237 blocks where benefits run to FY2032 or later; and
- 462 intermediate or mixed-calendar blocks that are not part of the comparison.
From 2016–2019 to 2024–2025, the median price on the near-expiration blocks increased 7.8 percent, compared with 13.2 percent on the long-runway blocks. The difference was 5.4 percentage points.
The pattern also appeared within most of the neighborhoods where both calendar groups could be compared. Eleven of seventeen same-neighborhood comparisons moved in the predicted direction. In Williamsburg North, for example, the near-expiration blocks appreciated 25.0 percent, compared with 34.6 percent for blocks whose benefits ran to FY2032 or later: a 9.6-point difference.
This comparison is broad but coarse. Tax blocks contain sales from buildings without 421-a, and the two groups can differ in vintage, product mix, condition and buyer profile. It narrows the comparison; it does not make it causal.
The same-apartment comparison
The second test follows 43 repeat-sale pairs in three Manhattan condominium buildings. Each pair begins with an arms-length, non-sponsor purchase two to twelve years before the building’s first fully taxable year and ends with a resale on or after it.
The median apartment changed by −2.8 percent in nominal terms. Over each pair’s matching holding period, the Manhattan condominium market rose by a median 31.4 percent. Subtracting the corresponding market movement from each apartment’s result produced a median market-adjusted gap of −26.0 percent. Forty-one of the 43 pairs trailed the market benchmark.
Following the same apartment controls for many characteristics that weaken a broader comparison, but it does not reveal renovation, condition or the circumstances of either sale. The panel is also small and concentrated in three buildings. The result is a pricing signal, not a universal discount.
What the record supports
Properties at or near expiration underperformed their selected comparison groups at both the market and apartment level. The analysis does not isolate the tax schedule from every other influence on price. It does show that the expiration calendar is associated with differences large enough to matter in valuation and negotiation.
The correct use of the research is not to apply the same discount everywhere. It is to ask three questions building by building:
- How much benefit remains?
- What will full taxation cost?
- Has the current asking price already absorbed that future expense?
For an owner, the first fully taxable year belongs in the discussion before choosing a sale date or asking price. For a buyer, the terminal bill matters more than the bill printed on the listing. When comparing apartments, both should be normalized to their projected fully taxable monthly cost. Co-op and condominium boards should communicate the schedule and its assumptions clearly, while recognizing that unit-level taxes and eligibility for a separate abatement can vary by owner.
The broader 421-a record
The ownership analysis is one view of a larger citywide record. Across all tenures, recorded benefit schedules at 4,769 buildings and an estimated 66,313 apartments end during FY2023–FY2030. Another 4,575 buildings and an estimated 93,940 apartments follow during FY2031–FY2040.
A separate rent-stabilization screen identifies approximately 40,700 rental apartments in 2,634 buildings that may be exposed during FY2023–FY2030. That figure is a screening estimate, not a deregulation forecast. Required lease notices, affordability restrictions and other regulatory agreements can preserve stabilization after a tax benefit ends. The rental screen is not additive to the ownership count because mixed condominium declarations can appear in both analytical views.
Method and sources.
The counts are derived from New York City Department of Finance Property Exemption Detail records for assessment-roll years 2021–2027. Earlier rolls are necessary because properties can disappear from later records after a benefit ends. Applicable 421-a exemption codes and their construction variants were retained; unrelated programs including 421-b, 421-g, J-51, 467-m and 485-x were excluded. Within each roll year, the latest assessment period was retained for each lot and code.
Condominium unit lots were consolidated by Department of Finance condominium declaration number; non-condominium property was grouped by borough-block-lot. Expiration is the recorded benefit-start year plus the stated term, expressed as the first fully taxable fiscal year. Building counts use Department of City Planning PLUTO NumBldgs. Apartment counts draw from PLUTO residential units, individually lotted residential condominium classes and qualifying co-operative records. Four materially mixed declarations use a residual estimate. The result is a property-level estimate rather than a component-exact census.
No six-unit minimum was imposed. Qualifying smaller properties were retained when historical Department of Finance records carried an applicable older-program 421-a code. A separate current-BIN check was used as a building-level sensitivity test; PLUTO NumBldgs remains the published measure.
The pricing database was updated through September 10, 2026. The block and repeat-sale tests are descriptive rather than causal and do not control for every difference in unit mix, renovation, seller motivation or building condition.
The property-level records behind the rental-stabilization screen and the wider-cohort figures are published as a source workbook, including the counting bases, the multi-schedule exclusions and the audit tabs.
Suggested attribution: Roebling Index analysis of New York City Department of Finance and Department of City Planning records.
For an explanation of the program itself and the documents a buyer should request, read The 421-a Tax Abatement: What It Is and What Happens When It Expires.
The 421-a Expiration Wave, Edition 1.0 (PDF, 15 pages)
Charts, the year-by-year calendar and the full technical note.
Source workbook (Excel, 700 KB)
The property-level records behind the rental-stabilization screen and the wider-cohort figures, with the counting bases and audit tabs. Published so the counts can be checked rather than taken on trust.
Corey Cohen is a Manhattan residential broker and publisher of The Roebling Index, a building-level research platform developed from more than 580,000 recorded transactions across Manhattan, Brooklyn and Queens. The Roebling Research Library includes more than 3,001 public building profiles, developed from a broader research warehouse covering recorded transactions across more than 57,000 buildings. Each profile carries building, neighborhood and corridor pricing research designed for actual transaction decisions.
The research underwrites The Roebling Team’s brokerage practice: pricing, negotiation and diligence for buyers and sellers of Manhattan co-operatives and condominiums, with coverage centered on the Upper East Side, Upper West Side, Tribeca, and the Park Avenue, Fifth Avenue and Central Park West corridors.
The counts in this article are derived from New York City Department of Finance and Department of City Planning records; they are not published city statistics. This material is for research purposes and is not legal, tax or investment advice.
Working the question on a specific apartment.
The research is a calendar and a signal. Turning it into a number for one apartment takes three steps: what it is worth, what it will cost to hold once the benefit ends, and what the sale side of that looks like.
The Roebling Valuation
The report's conclusion is that the expiration year belongs in a valuation. This is the valuation, built from recorded sales rather than an automated estimate.
True Monthly Carrying Cost Calculator
Normalises two apartments to their projected fully taxable monthly cost — the comparison the report argues buyers should be making.
NYC Pied-à-Terre Tax Calculator
A second tax schedule now running against the same carrying cost, for an apartment that is not the owner's primary residence.
Seller Closing Cost Calculator
For an owner weighing a sale date against a remaining benefit, the other side of the arithmetic.
Buildings in the library with a recorded 421-a benefit
Each profile carries the building’s recorded benefit term and its first fully taxable year alongside its sales history. These six are a sample; 146 profiled buildings carry a 421-a record.
- 35 Hudson Yards20-year benefit · FY2040
- One Manhattan Square20-year benefit · FY2040
- One West End20-year benefit · FY2040
- The Kent, 200 East 95th Street20-year benefit · FY2040
- The Edge, South TowerWilliamsburg, 25-year benefit · FY2037
- The Greenpoint, 21 India Street25-year benefit · FY2045
What does this mean for a specific building?
The research says the expiration year belongs in a valuation. The useful version of that is building-specific: how much benefit remains, what full taxation will cost, and whether the asking price has already absorbed it. That is the analysis we run for clients on a named address.
