(1) In general This section shall be applied with respect to a United States shareholder of the controlled foreign corporation separately with respect to each foreign country in which the controlled foreign corporation conducts any trade or business. (2) Special rules (A) In general For purposes of making country-by-country determinations under this section and sections 904 and 960 with respect to net CFC tested income for a taxable year pursuant to paragraph (1)— (i) taxes paid or accrued to a foreign country by the controlled foreign corporation shall be assigned to that country, and (ii) earnings to which such taxes relate shall be treated as income assigned to the country to which those tax payments are made. (B) Earnings assigned to two or more countries If the same earnings are assigned to two or more countries under subparagraph (A), for purposes of paragraph (1) such earnings and the taxes related thereto shall be treated as assigned to the country with the highest statutory corporate tax rate. (3) Earnings not subject to tax If earnings are not subject to tax by any country, then with respect to those earnings paragraph (1) shall not apply. (4) Regulations The Secretary shall prescribe such regulations as may be necessary or appropriate to carry out this subsection, including the time period in which foreign earnings and the associated foreign taxes are assigned to a country. . (c) Effective date The amendments made by this section shall apply with respect to taxable years of controlled foreign corporations beginning after December 31, 2018, and to taxable years of United States shareholders in which or with which such taxable years of foreign corporations end. 3. Study and report on restructuring international tax laws (a) Study The Chief of Staff of the Joint Committee on Taxation shall study options for the reform of laws related to the taxation of income from international sources, including the provisions of sections 59A, 250, and 951A of the Internal Revenue Code of 1986. Such study include an