According to recent reports, U.S. Treasury Secretary Steven Mnuchin has asked Puerto Rico's government to prepare a proposal for the end of the IRS' acceptance of a foreign tax credit (FTC) for Puerto Rico's excise tax. The 4% excise tax was introduced by Puerto Rico under Act 154 in order to tax purchases by multinational companies from their CFCs in Puerto Rico because, under tax agreements with the island’s government, nearly all the income earned by CFCs of primarily U.S. multinationals i…