(a) Notwithstanding any provisions of State law, regulation or interpretation to the contrary, this Part constitutes the exclusive authority for banks, trust companies, savings banks, savings and loan associations, credit unions, persons and entities engaging in the business described in section 590, article 12-D of the Banking Law (other than federally licensed branches and agencies of foreign banking corporations, national banks, Federal savings banks, Federal savings and loan associations, Federal credit unions and their subsidiaries which are exempt from licensing as mortgage bankers) and branches or agencies of foreign banking corporations licensed pursuant to article II of the Banking Law (“lender”) to make, sell, purchase or participate in mortgage loans in a principal amount of less than $250,000 other than fixed-rate, equal payment, self-amortizing loans. For purposes of this Part, the term mortgage loan is limited to the types of loans described in section 82.2(a) of this Part. Such institutions may make, sell, purchase or participate in the types of mortgage loans described in this Part, provided all such loans are made in accordance with the provisions of this Part. Such loans shall be repayable either in biweekly or in monthly installments. The authorization for graduated payment mortgage loans contained in this Part is made pursuant to the superintendent’s authority under section 6-f of the Banking Law, any other provisions of State law to the contrary notwithstanding. Mortgage loans in the principal amount of $250,000 or more, which would otherwise not be subject to this Part, may be structured to provide for negative amortization, if the lender adheres to the provisions of sections 82.5 and 82.6 of this Part.

(b) Nothing in this Part authorizes a mortgage loan which contains a demand feature or a mortgage loan which is structured either as a price level adjusted mortgage (PLAM) or a shared appreciation mortgage (SAM). Further, a balloon mortgage loan, a pledge-account mortgage loan and a growing equity mortgage loan may not be structured to provide for negative amortization.