What must nonresident aliens do on a Form W-4?

Nonresident aliens have specific requirements when completing Form W-4 to ensure proper withholding for federal income tax purposes.

Checking "Single" on line 3 is necessary because nonresident aliens are effectively treated as single taxpayers for withholding purposes, regardless of their actual marital status. This is important for determining the correct withholding rate.

Claiming only one withholding allowance on line 5 is another requirement. Nonresident aliens generally can only claim a single allowance because they do not benefit from the same deductions and credits as resident aliens or U.S. citizens. This is aligned with the IRS guidelines on withholding allowances for nonresident aliens.

Writing "NRA" (Nonresident Alien) above the dotted line in line 6 is a crucial step specifically for nonresident aliens. This notation alerts the employer to apply the appropriate tax withholding rules that apply to nonresident aliens, ensuring compliance with federal tax regulations.

Since all the actions listed are required for nonresident aliens on the Form W-4 to accurately reflect their tax status and withholding needs, the comprehensive answer encompasses all of these requirements.