N.Y. Comp. Codes R. & Regs. tit. 9, § 2505.7 – Subletting; assignment.

(a) Housing accommodations subject to these regulations may be sublet in accordance with the provisions, and subject to the limitations, of section 226-b of the Real Property Law provided the additional provisions of this section are complied with and provided further that the prime tenant can establish that at all times he has maintained the housing accommodation as his primary residence and intends to occupy it as such at the expiration of the sublease.
(b) The rental charged to the subtenant shall not exceed the legal regulated rent plus a 10-percent surcharge payable to the prime tenant if the housing accommodation is sublet with the prime tenant's furniture. Where a prime tenant violates the provisions of this subdivision, the subtenant shall be entitled to damages as provided in section 2506.1 of this Title.
(c) The tenant may not sublet a housing accommodation for more than a total of two years, including the term of the proposed sublease, out of the four-year period preceding the termination date of the proposed sublease, but this provision shall not apply to any sublease commencing prior to July 1, 1983. The term of a proposed sublease may, if lawful under this section, extend beyond the term of the prime tenant's lease, and a landlord may not refuse consent to a sublease solely because it extends beyond such term. A sublease which so extends shall be subject to the prime tenant's right to a renewal lease.
(d) The prime tenant, rather than the subtenant, retains the right to (1) a renewal lease, whether or not the term of the sublease extends beyond the term of the prime tenant's lease; and (2) the rights and status of a tenant in occupancy with respect to conversion to condominium or cooperative ownership.
(e) An owner may terminate the tenancy of a tenant who sublets or assigns contrary to the terms of this section, but no action or proceeding based upon the nonprimary residence of a tenant may be commenced prior to the expiration date of his lease.
(f) Upon the consent of an owner to an assignment, regardless of whether or not the lease is a renewal lease, the legal regulated rent payable to the owner effective upon the date of such assignment may be increased by:
1. (1) the increase provided for in section 2502.7 of this Title; and
2. (2) which may be further increased by the vacancy allowance, if any, provided in the rent guidelines board order in effect at the time of the commencement date of the lease.
  Such increases shall remain part of the legal regulated rent for any subsequent renewal lease.