N.J. Stat. § 54:16-2: Imposition of tax

With the exception of license fees, real estate and personal property taxes and taxes under the reciprocal provisions of section 17:32-12 of the title Corporations and Institutions for Finance and Insurance, every insurer organized, admitted or licensed to transact the business of marine insurance in this state shall, with respect to all marine insurances written within this state, be taxed only on that proportion of the total underwriting profit of such insurer from such marine insurances written within the United States, which the gross premiums of the insurer from such insurance written within this state bear to the gross premiums of such insurers from such insurance written within the United States.