N.Y. Comp. Codes R. & Regs. tit. 20 § 296.2
General City Law, § 8-A of § 25-m; Administrative Code of the City of New York, § 11-1909
The amount of New York City earnings tax on nonresidents of such city to be deducted and withheld by an employer from wages subject to such earnings tax must be determined in accordance with one of the following withholding methods:
Method VI-Wage Bracket Table Method
Method VII-Exact Calculation Method
Method VIII-Annualized Tax Method
In case of special situations, however, an employer may apply to the department for permission to use another method. The wage bracket table method, the exact calculation method and the annualized tax method are obtainable in booklet form (Publication WT-100) from the Taxpayer Assistance Bureau of the New York State Department of Taxation and Finance, or from any New York State district tax office. Instructions for withholding, payment and reporting of the New York City earnings tax on nonresidents are also available in Publication WT-100.
N.Y. Comp. Codes R. & Regs. Tit. 20 § 296.2