N.Y. Comp. Codes R. & Regs. tit. 9 § 2503.9
Every landlord of housing accommodations subject to this Chapter, for which the initial legal regulated rent includes payments reserved under a tax escalation clause in the lease or other rental agreement shall whenever there is a reduction in the amounts of increases in the real property taxes which were previously in effect, on or before July 31, 1976 or within 60 days after notice of such reduction and receipt of rebates from the taxing authority, whichever is later, give notice in writing by certified mail to the tenant of each such housing accommodation on a form provided by the division for that purpose, reciting the redetermined initial legal regulated rent for the housing accommodation, and the amount of the payments previously included in the initial legal regulated rent, which are excluded therefrom based upon the reduction of real property tax increases, and that all refunds of excess rent paid since the local effective date will be made in cash to the tenant or as a credit against future rents over a period not in excess of six months. In the event the initial legal regulated rent has been adjusted by the applicable Rent Guidelines Board rate in a one-, two- or three-year lease, the legal regulated rent provided in such lease.
N.Y. Comp. Codes R. & Regs. Tit. 9 § 2503.9