N.Y. Comp. Codes R. & Regs. tit. 9 § 2523.1
Every owner of housing accommodations previously subject to the City Rent Law and thereafter rented to a tenant on or after April 1, 1984, shall within 90 days after the commencement of the first tenancy subject to the RSL, give notice in writing by certified mail to the tenant of each such housing accommodation on a form prescribed by the DHCR for that purpose, reciting the initial legal regulated rent for the housing accommodation and the tenant's right to file an application for adjustment of the initial legal regulated rent within 90 days of the certified mailing to the tenant of the notice pursuant to section 2522.3 of this Title. Compliance with section 2528.2 of this Title shall also be considered compliance with this section.
N.Y. Comp. Codes R. & Regs. Tit. 9 § 2523.1