New York Codes, Rules and Regulations
Title 20 - DEPARTMENT OF TAXATION AND FINANCE
Chapter II - Income Taxes and Estate Taxes
Subchapter F - New York City Earnings Tax On Nonresidents
Part 297 - Combined Returns, Single Payments Returns And Payments Of Tax
Section 297.2 - Payment of a single amount to the department

General City Law, § 14 of § 25-m; Administrative Code of the City of New York, § 11-1915(2)

Where a combined return or combined employer's return is required and with respect to the payment of estimated tax, the commissioner may require (including by means of forms and instructions) the payment of a single amount, which amount shall be the total of all the amounts required to be paid under the provisions of article 22 of the Tax Law relating to New York State personal income tax, article 30 of the Tax Law and chapter 17 of title 11 of the Administrative Code of the City of New York relating to City of New York personal income tax on residents, article 2-E of the General City Law and chapter 19 of title 11 of the Administrative Code of the City of New York relating to City of New York earnings tax on nonresidents, article 30-A of the Tax Law and article IX of the Codes and Ordinances of the City of Yonkers relating to City of Yonkers income tax surcharge on residents, and article 30-B of the Tax Law and article X of the Codes and Ordinances of the City of Yonkers relating to City of Yonkers earnings tax on nonresidents.