Who is require to withhold? • Withholding Agent.The eligible Foreign National must complete IRS Form 8233 and the Tax Treaty Affidavit. In most cases, the University is required to withhold federal taxes from payments made to or on behalf of foreign nationals in NRA status. The IRS uses Form W-8BEN to track the income that non-US citizens and foreign businesses generate while contracting with American companies. To elect an Arizona withholding percentage, an employee must complete Arizona Form A-4, and submit it to their employer. Let me give you a high-level answer since there are many factors that determine whether or not you need to pay taxes in the US. If services are performed in the US, income is USsourced. However, even without tax withholding, tax reporting may still be necessary.