This page contains information about data sources and limitations for SOI's Foreign Recipients of U.S. Income Study. Please visit Foreign Recipients of U.S. Income Statistics to access articles and tables from the study. Payers (or their authorized withholding agents) of most U.S.-source income to foreign persons must withhold tax in accordance with the Internal Revenue Code Section 1441. Form 1042-S, Foreign Persons' U.S.-Source Income Subject to Withholding, is filed by the payer to report this income and the U.S. tax withheld. Often a financial institution acts as the payer's withholding agent. The SOI statistics were tabulated by calendar year, using all Forms 1042S filed with the Internal Revenue Service. The data reflect the income that was paid and U.S. tax that was withheld for the particular tax year. Because all Forms 1042S were used for the statistics, the data are not subject to sampling error. However, the data are subject to nonsampling error, including data entry and taxpayer reporting errors. Although the data were subjected to tests for certain basic mathematical relationships, including the calculation of the correct tax withheld, the possibility of error can not be completely eliminated.