The Pre-2019 Toolkit

Before HSTPA, owners of rent-stabilized buildings had several tools that made it economically viable to invest in aging units:

  • Individual Apartment Improvements (IAI). Owners could raise the legal rent on a specific unit to recoup the cost of renovations made to that apartment, typically upon vacancy.
  • Major Capital Improvements (MCI). Building-wide capital work — new roofs, boilers, windows — could be passed through to all stabilized tenants as a rent increase.
  • The vacancy bonus. Rents could be increased by a set percentage each time a unit turned over to a new tenant.
  • High-rent/high-income deregulation. Units that reached a certain rent threshold could exit rent stabilization entirely and move to market rate.

Together, these tools created a clear "upside story": a long-held, below-market unit could be renovated on turnover, and the cost of that renovation could realistically be recovered through legal rent increases over a reasonable period.

What HSTPA Changed

The 2019 HSTPA reforms narrowed or eliminated nearly every one of these tools:

  • IAI increases are now capped very low — both in the dollar amount that can be passed through per month and in how frequently they can be applied over a unit's life.
  • MCI increases are capped at a modest annual percentage and now sunset after a period of years rather than remaining permanently in place.
  • The vacancy bonus was eliminated entirely — a unit no longer gets an automatic rent increase simply because a new tenant moves in.
  • Vacancy and high-rent deregulation were eliminated. A stabilized unit, once vacated, generally stays stabilized indefinitely — there is no longer a path for it to exit the system through rent level alone.

For a deeper look at how these changes affect a building's overall valuation methodology, our companion guide on how rent stabilization affects overall building value covers that broader picture. This article focuses specifically on what happens at the individual unit level.

Why the Math No Longer Works

Consider a unit that has been under the same tenancy for many years, with rent held well below what a gut renovation would justify at market rate. Before 2019, an owner could vacate, renovate, and recover the cost through an IAI increase and the vacancy bonus, then continue collecting a higher legal rent going forward. Today, the IAI cap alone often means the achievable rent increase is a small fraction of what a genuine gut renovation costs — and because the vacancy bonus is gone and the unit stays stabilized permanently, there's no realistic mechanism to ever fully recover a significant renovation investment.

Many owners now find that a long-held, deeply below-market stabilized unit simply cannot be renovated at a legal rent that justifies the expense — the math that used to work in 2015 or 2018 often no longer works at all.

The Practical Effect: Vacant Units That Stay Vacant

The direct consequence is one that's become increasingly common across the city's older rent-stabilized stock: units sit vacant, sometimes for extended periods, because renovating them at a loss doesn't make financial sense, and re-leasing them without renovation isn't always feasible or code-compliant. A handful of vacant, un-renovated units in an otherwise occupied building can meaningfully drag down that building's overall net operating income and, in turn, its value — even though every other unit may be performing normally.

What This Means for Owners

If your building includes stabilized units that have been vacant for a while, or units where a needed renovation clearly won't pencil out under current IAI and MCI caps, it's worth having an honest conversation about what those units are actually contributing — or costing — the property today. This is exactly the kind of nuance that a generic, comp-based estimate tends to miss, and that a proper valuation should account for directly.

Some owners respond by holding vacant units off the market entirely rather than re-leasing at a rent that doesn't reflect the unit's condition. Others do minimal, code-compliant work rather than a full renovation, accepting a lower rent in exchange for keeping the unit occupied and generating some income. Neither approach is inherently right — the better choice depends on the specific unit, the building's overall financial picture, and the owner's plans for the property.

Get an Accurate Picture of Your Building's Value

Many owners are surprised by how much unit-level stabilization economics affect an overall sale price — in both directions. An accurate valuation looks at your building unit by unit, factoring in which apartments are performing, which are constrained by HSTPA's caps, and what that means for a buyer's underwriting.