Buying rent-stabilized apartment buildings in New York City after the Housing Stability and Tenant Protection Act (HSTPA) of 2019 takes a different playbook from the one that drove the 2010–2018 value-add wave. Vacancy bonuses are gone. Individual Apartment Improvement (IAI) rent increases are capped. Major Capital Improvement (MCI) passthroughs are cut back. Preferential rents are mostly locked in. Rent-stabilized buildings still work for investors who underwrite realistically, use the right capital structure, and are patient operators. This guide is the playbook as it stands in 2026.
Why HSTPA changed the math (and why old comps lie)
The Housing Stability and Tenant Protection Act of 2019 took apart every major source of upside behind the 2010–2018 rent-stabilized trade. High-rent vacancy decontrol: eliminated. High-rent high-income decontrol: eliminated. IAI increases on apartment renovations were capped at small dollar amounts amortized over long periods. MCI building-wide improvements were capped and given a sunset. Preferential rents, meaning the gap between the legal regulated rent and the rent actually in the lease, were largely locked in.
Investors who underwrite rent-stabilized buildings today off 2015–2018 comps overpay, every time. The asset class still yields. That yield comes from in-place cash flow bought at a defensible basis, and no longer from gaming the regulations.
IAI and MCI: what they actually deliver in 2026
Individual Apartment Improvements (IAIs) and Major Capital Improvements (MCIs) are still the two main ways to raise stabilized rents beyond the annual Rent Guidelines Board (RGB) increase. Both have been cut back hard, and both still have real economic value when you underwrite them correctly.
IAI mechanics
Under HSTPA, an owner can raise the legal regulated rent on a vacant or occupied stabilized unit by a formula tied to the cost of qualifying improvements, capped at $15,000 of qualifying work over a 15-year period. The monthly increase is the lesser of the formula amount or a hard cap, currently $89 (under-35-unit buildings) or $83 (35+ unit buildings). That is a small fraction of the upside owners had before HSTPA.
Disciplined IAI underwriting starts with three questions. Which units are actually vacant or likely to turn? What do qualifying improvements really cost in this submarket? And where will the post-IAI legal rent land against the preferential or contract rent? An IAI that never reaches collectible rent is an accounting entry, nothing more.
MCI mechanics
Major Capital Improvements (building-wide capex such as boilers, roofs, facades, and elevators) still produce rent passthroughs to stabilized tenants, under tighter HSTPA rules: a 2% annual cap on the resulting rent increase, 12-year amortization in most cases, and a sunset on the increase after 30 years. MCI underwriting has to show the gap between gross capex spend and net rent recovered, and in many cases the cash-on-cash recovery is in single digits.
Preferential rents: the quiet value killer
A preferential rent is a rent the owner agrees to charge that is below the legal regulated rent allowed under stabilization. Before HSTPA, an owner could raise a preferential rent to the legal regulated rent at lease renewal. After HSTPA, for leases signed after June 14, 2019, the preferential rent generally becomes the new regulated baseline, and the gap to the legal rent is effectively lost.
Buyers of rent-stabilized buildings have to separate three numbers on every stabilized unit: the legal regulated rent (as registered with DHCR), the preferential rent (if there is one, per the lease), and the rent actually collected. Offering memoranda often present the gap between legal and preferential as 'upside.' Since HSTPA, on most leases, that gap can't be recovered. Counting it as upside is the most common underwriting error in stabilized acquisitions.
DHCR registration and rent history: non-negotiable diligence
Every stabilized unit in NYC has to be registered each year with the New York State Division of Housing and Community Renewal (DHCR). The registration history sets the legal regulated rent for the unit and controls in any tenant dispute. Gaps, errors, or fraudulent registrations expose the owner to overcharge claims under the four-year (and in some cases six-year) look-back rule, with treble damages and attorney's fees.
A DHCR audit before you sign is non-negotiable. Pull the full registration history for every stabilized unit and check it against the rent roll. Flag gaps, suspicious jumps, and missing registrations. Have counsel put a number on the overcharge exposure. Then either price it in or walk.
A realistic underwriting framework
- Start with in-place collectible rent. Not legal regulated rent, not preferential rent, not asking rent.
- Use a realistic RGB increase schedule for the hold period; in recent cycles the RGB has leaned toward modest 2-4% increases.
- For IAIs, count only units you realistically expect to turn, apply the post-HSTPA caps, and do not assume turnover faster than the building has historically seen.
- Load capex: Local Law 11 facade cycle, Local Law 97 emissions retrofit, boilers, elevators, roof, lead, asbestos. Most stabilized buildings carry $30K–$100K+ per unit of latent capex.
- Tax-abatement audit: J-51, 421-a, 467-m status, abatement expiry, claw-back exposure.
- Refinance assumption: agency DSCR underwriting on stabilized cash flow at exit. Do not underwrite a stabilized rent roll as if it will reach market rents.
The cap-rate spread: where the yield actually is
In 2026, heavily rent-stabilized Manhattan buildings trade at going-in cap rates well above free-market comps in the same submarket, typically 100–300 basis points wider depending on stabilized share, capex, and tax status. For investors with patient capital and realistic operating assumptions, that spread is the yield. Don't treat it as a discount that operating improvements will close. It is permanent pay for taking on the regulatory environment.
The operators who do well here know DHCR registration inside out, have strong relationships with NYC community banks for balance-sheet loans, are willing to hold through cycles, and keep regulatory-arbitrage fantasies out of their models.
Financing rent-stabilized buildings: channels and constraints
Stabilized buildings finance differently from free-market ones. Agency lenders (Fannie Mae, Freddie Mac) underwrite a stabilized rent roll at the in-place collected rent, not at the legal regulated rent and not at preferential rent rolled forward, and they apply conservative DSCR thresholds. NYC community and savings banks have historically been the most flexible balance-sheet lenders on stabilized collateral. They know the regulatory framework well and will lend on rent-roll structures agency lenders sometimes turn down.
Bridge debt is available for value-add stabilized acquisitions, but it is expensive. Refinance risk at exit has to be underwritten against agency or balance-sheet DSCR thresholds on stabilized NOI, not on hoped-for mark-to-market rents. The buyers who execute stabilized acquisitions again and again are the ones with established NYC community-bank relationships and an operating record that lets them refinance at stabilization without trouble.
Tenant buyouts in stabilized buildings: what is allowed
Buyouts of rent-stabilized tenants are still legal, but the Tenant Protection Act and related rules now restrict them. Before offering or discussing a buyout, the owner must give the tenant a written disclosure of their rights. No solicitation can involve harassment. After a tenant declines, the owner must observe a 180-day cool-off period in which further solicitation is prohibited. Violations expose owners to harassment claims, treble damages, and in some cases criminal liability.
Buyouts can still be worth doing when an owner needs vacant possession: to reposition units to free-market under the mechanisms that remain, to resolve chronic tenant disputes, or to recover units for owner use. Disciplined owners run buyout programs with counsel involved and keep a paper trail showing they followed the disclosure and cool-off rules.
Exit strategies for stabilized buildings
Stabilized buildings have real exit options, just fewer than free-market buildings. For buy-and-hold investors, the main exit is still a refinance at stabilization, usually through an NYC community bank comfortable with rent-stabilized collateral. The second is a sale to another operator experienced with stabilized stock, at a similar cap-rate basis. Conversion or a major repositioning rarely works under current regulation. Underwrite a refinance-and-hold exit by default and count any premium exit as upside, never as the base case.
Skyline Properties brokers rent-stabilized building sales across Manhattan and Brooklyn. Robert Khodadadian's $976M+ closed-deal record includes a meaningful number of rent-stabilized buildings in the LES, Harlem, the UWS, Williamsburg, and Bushwick.
Sales to other operators do happen, especially in a favorable cap-rate environment and when the seller has already done real capex and rent-roll cleanup. A buyer pays more readily when the seller has completed the DHCR audit, the Local Law 11 facade work, a Local Law 97 baseline assessment, and rent-roll normalization, all things an experienced buyer would otherwise have to underwrite. Sellers who clean up before marketing get better prices, consistently.
Frequently asked questions
- Should I avoid rent-stabilized buildings entirely after HSTPA?
- No, but you have to underwrite them on their own terms. Many experienced NYC multifamily investors keep buying stabilized buildings because the going-in yield, properly underwritten, pays for the regulatory risk. The mistake is buying them on pre-2019 assumptions. The asset class works. The playbook has changed.
- How do I check DHCR registration history before buying?
- You can request the full registration history (DHCR Form RA-90) for any rent-stabilized unit directly from DHCR. Most experienced NYC multifamily attorneys do this routinely before the LOI or early in diligence. Skyline Properties includes a DHCR audit in every stabilized building diligence package.
- Can I still raise rents on rent-stabilized units?
- Yes, within the rules: the annual RGB increase, IAIs subject to the post-HSTPA caps and amortization, and MCIs subject to the 2% annual passthrough cap and 12-year amortization. The pre-2019 tools, the vacancy bonus and high-rent decontrol, are gone.
- What is the typical cap-rate spread between stabilized and free-market buildings?
- Heavily stabilized buildings trade roughly 100–300 basis points wider than free-market comps in the same Manhattan submarket. The exact spread depends on stabilized share, capex condition, tax-abatement status, and the capital markets. It is real, lasting compensation for the regulatory environment, and it will not correct as a temporary mispricing would.
- Are MCIs still worth pursuing?
- For capital projects the building needs anyway (boilers, roofs, facades, elevators), yes. The underwriting just has to reflect the post-HSTPA caps, the amortization, and the 30-year sunset on the rent increase. Net cash-on-cash recovery on MCIs is much lower than it was before HSTPA. Treat them as one tool for running a stabilized building; on their own they won't create much value.