(a) Allocation of entire net income. The portion of entire net income of a taxpayer to be allocated within the state shall be the amount determined by multiplying such income by the income allocation percentage determined by:

1. (1) ascertaining the percentage which the taxpayer's New York premiums for the taxable year bear to the taxpayer's total premiums for the taxable year, and multiplying such percentage by nine,
2. (2) ascertaining the percentage which total wages, salaries, personal service compensation and commissions for the taxable year of employees, agents and representatives of the taxpayer within New York bear to the total wages, salaries, personal service compensation and commissions for the taxable year of all the taxpayer's employees, agents and representatives, and
3. (3) adding the amounts determined under paragraphs one and two and dividing the sum by ten.

(2) For purposes of paragraph one of subdivision (a), "New York premiums" shall be determined as follows:

1. (A) For all premiums other than premiums described in subparagraph (B) or (C) of this paragraph, "New York premiums" means that portion of total premiums written, procured or received on property or risks located or resident in New York and shall also include premiums written, procured or received in this state on business which cannot be specifically assigned as located or resident in any other state or states, other than premiums described in subdivision (b) of section fifteen hundred twelve. Provided however, in the case of special risk premiums, "New York premiums" shall include only those premiums written, procured or received in this state on property or risks located or resident in this state.
2. (B) For premiums on reinsurance, "New York premiums" shall be determined as provided in subparagraph (A) of this paragraph except that where the location or residence of the property or risk covered by the reinsurance cannot be ascertained, "New York premiums" shall mean the portion of premiums for reinsurance determined by multiplying the amount of premiums from reinsurance ceded by each company to the taxpayer by the percentage determined under paragraph one of subdivision (a) of this section for each such ceding company for the preceding taxable year.
3. (C) For premiums from marine insurance, "New York premiums" means (i) that portion of premiums from such marine insurance as are written, procured or received on property or risks located or resident in this state and, (ii) to the extent not otherwise includible in "New York premiums" under clause (i) hereof, the premiums for such marine insurance written within this state on property or risks which cannot be specifically assigned as located or resident in any other state or country, provided however, in the case of special risk premiums, "New York premiums" shall include only those premiums written, procured or received in this state on property or risks located or resident in this state. For purposes of this subparagraph, marine insurance means insurance written, procured or received upon hulls, freights or disbursements, or upon goods, wares, merchandise and all other personal property and interests therein, in the course of exportation from, importation into any country, or transportation coastwise, including transportation by land or water from point of origin to final destination in respect to, appertaining to, or in connection with, any and all risks or perils of navigation, transit or transportation, and while being prepared for, and while awaiting shipment, and during any delays, storage, transshipment or reshipment incident thereto, including war risks and marine builder's risks.

(d) If it shall appear to the tax commission that the income allocation percentage determined as hereinabove provided does not properly reflect the activity, business or income of a taxpayer within the state, the tax commission shall be authorized, in its discretion, to adjust it by:

1. (1) excluding one or more factors therein;
2. (2) including one or more other factors therein, such as expenses, purchases, receipts other than premiums, real property or tangible personal property;
3. (3) or any other similar or different method calculated to effect a fair and proper allocation of the income and capital reasonably attributable to the state. The tax commission from time to time shall publish all rulings of general public interest with respect to any application of the provisions of this subdivision.