Withholding agent doesn't know the tax residency. In general, if a withholding agent cannot reliably associate a payment with valid documentation (e.g. Form.The Tax Department is streamlining withholding tax and wage reporting forms and Web File applications. Chapter 2 discusses the withholding of income, social security, and Medicare taxes from the pay of U.S. citizens and resident aliens. Do you need a 1099 for international contractors? Your guide for understanding how to hire and pay independent contractors around the world. Employers are only required to withhold the LST on a payroll period basis for those payroll periods in which the taxpayer is employed. Must not be included in a composite return, but should separately pay estimated taxes as an individual using.