A flat tax of 30 percent was imposed on U.S. source capital gains in the hands of nonresident alien individuals physically present in the United States for 183 days or more during the taxable year. (money.stackexchange.com)
This document contains final and temporary regulations regarding withholding of tax on certain U.S. source income paid to foreign persons, information reporting and backup withholding with respect to payments made to certain U.S. persons, and portfolio interest paid to nonresident alien individuals and foreign corporations. (law.cornell.edu)
These regulations are related to withholding of tax on certain U.S. source income paid to foreign persons, information reporting and backup withholding with respect to payments made to certain U.S. persons, and portfolio interest paid to nonresident alien individuals and foreign corporations. (law.cornell.edu)