9 NYCRR § 2521.1 — Initial legal regulated rents for housing accommodations (Rent Stabilization Code, via Cornell LII)

(i)
maintenance or carrying charges, common charges, or rent in effect immediately
prior to such conveyance;

(ii) any
minimum standard rent established by either HPD or DHCR as the respective
supervising agency of an HDFC that was in effect immediately prior to such
conveyance, even if such minimum standard rents had not been implemented for
the specific building or housing accommodation; or

(iii) the rent specifically set by HPD or
DHCR as the respective supervising agency of an HDFC where such HDFC or a
successor HDFC continues to own the building.

(m)

(1)
Where an owner combines two or more vacant housing accommodations or combines a
vacant housing accommodation with an occupied rent regulated accommodation,
such initial rent for such new housing accommodation shall be the combined
legal rent for both previous housing accommodations, subject to any applicable
guidelines increase and any other increases authorized by this Title including
any individual apartment improvement increases applicable for both housing
accommodations. If an owner combines a rent regulated accommodation with an
apartment not subject to rent regulation, the resulting apartment shall be
subject to the rent stabilization law. If an owner increases the area of an
apartment not subject to the rent stabilization law by adding space that was
previously part of a rent regulated apartment, each apartment shall be subject
to the rent stabilization law.