More than 13K rent-stabilized units in NYC are sitting empty for multiple years, report finds
gothamist.com
A city Independent Budget Office report examines vacancy data from the state’s housing agency amid concerns of "warehousing."

Why? Because apparently they need some more incentive to keep units occupied. Also, even though a property might be vacant, there’s still imputed rental income there. Its owner is just receiving it in the form of enjoying the unit for himself instead of receiving an actual rent check from a tenant. That imputed rent ought to be taxed like any other income.