N.Y. Comp. Codes R. & Regs. tit. 20 § 269.4
Tax Law, § 7 of § 1340(c); Codes and Ordinances of the City of Yonkers, § 92-104
Every employer required to deduct and withhold City of Yonkers earnings tax on nonresidents, pursuant to section 7 of the Model Local Law contained in section 1340(c) of the Tax Law and section 92-104 of the Codes and Ordinances of the City of Yonkers (see section 269.1 of this Part), shall file an employer's return and with such return pay over to the Department of Taxation and Finance the amount of the City of Yonkers earnings tax so required to be deducted and withheld. An employer's return of City of Yonkers earnings tax withheld must be filed in the same manner as is provided for in Part 174 of this Title. However, in determining the threshold for filing such employer's return and making payment of City of Yonkers earnings tax withheld, the amount of City of Yonkers earnings tax required to be deducted and withheld shall be aggregated with the amounts of New York State personal income tax, City of New York personal income tax on residents, City of New York earnings tax on nonresidents and City of Yonkers income tax surcharge on residents required to be deducted and withheld, and the total of all such withheld amounts determines the manner and timing of filing such employer's returns and making payment of such withheld amounts.
N.Y. Comp. Codes R. & Regs. Tit. 20 § 269.4