N.Y. Comp. Codes R. & Regs. tit. 3, § 83.5
(a) Shared appreciation agreements may provide that the mortgagor shall share, in accordance with section 83.6 of this Part, in any appreciation in the value of the residential property with the holder in the event of a sale or transfer of the residential property or any interest therein, whether by deed, contract for deed or otherwise; including the following cases:
(b) The following cases do not necessitate a sharing, nor do they extinguish a holder’s claim to a share of the appreciation in value upon a subsequent sale or transfer:
(c) The following cases do not prevent a holder from sharing in any appreciation; rather, each entitles the holder to collect the aggregate principal balance, including the principal reduction and interest thereon, calculated at the modified note rate from the date of the shared appreciation agreement to the date of consummation of the transaction: