N.Y. RPT Law § 581-A

§ 581-a. Assessment of residential real property. Notwithstanding any\nother provision of law, the assessed valuation of real property used for\nresidential rental purposes where at least twenty percent of the\nresidential units are subject to an agreement with a municipality, the\nstate, the federal government, or an instrumentality thereof, which\nagreement restricts occupancy of those units to tenants who qualify in\naccordance with an income test, shall be determined using the income\napproach as applied to the actual net operating income, after deducting\nfor reserves required by any federal, state or municipal programs. For\nthe purposes of this section "net operating income" shall mean the\nactual or anticipated net income that remains after all operating\nexpenses are deducted from effective gross income, but before mortgage\ndebt service and book depreciation are deducted. The assessed valuation\nof real property used for such residential rental purposes shall be\ndetermined using the actual net operating income, and shall not include\nfederal, state or municipal income tax credits, subsidized mortgage\nfinancing, or project grants, where such subsidies are used to offset\nthe project development cost in order to provide for lower initial rents\nas determined by regulations promulgated by the division of housing and\ncommunity renewal.\n