N.Y. YTS Law § 15-109

§ 15-109. Combined filings.\n A. Notwithstanding anything to the contrary herein contained, the New\nYork State Tax Commission, with respect to the City of Yonkers income\ntax surcharge, may require the filing of any or all of the following:\n (1) A combined return which, in addition to the return provided for in\n§ 15-102, may also include any of the returns required to be filed by a\nresident individual of New York State pursuant to the provisions of §\n651 of the New York State Tax Law and which may be required to be filed\nby such individual pursuant to Article X of this chapter imposing a\nnonresidents' earnings tax, any local law enacted pursuant to Article\n2-E of the General City Law or Article 30 of the New York State Tax Law.\n (2) A combined employer's return which, in addition to the employer's\nreturn provided for by said Article X of this chapter, may also include\nany of the employer's returns required to be filed by the same employer\npursuant to the provisions of § 674 of the New York State Tax Law and\nrequired to be filed by such employer pursuant to Article X of this\nchapter imposing a nonresident earning tax, or any local law enacted\npursuant to Article 2-E of the General City Law, or Article 30 of the\nNew York State Tax Law.\n B. Where a combined return or employer's return is required, the State\nTax Commission may also require the payment to it of a single amount\nwhich shall equal the total of the amounts (total taxes less any credits\nor refunds) which would have been required to be paid with the returns\nor employer's returns pursuant to the provisions of Article 22 of the\nNew York State Tax Law, and the provisions of this article or Article X\nof this chapter imposing a nonresident earnings tax, or any local law\nenacted pursuant to authority granted in Article 2-E of the General City\nLaw.\n