Aliens who must file a tax return but are not eligible for a social security number should request which form from the IRS?

The correct form for aliens who must file a tax return but are not eligible for a Social Security number is the W-7 form. This form is specifically used to apply for an Individual Taxpayer Identification Number (ITIN), which is necessary for individuals who need to file a U.S. tax return but do not qualify for a Social Security number.

The W-7 is crucial because it allows these individuals to fulfill their tax obligations without a Social Security number, enabling the IRS to process their tax returns appropriately. Having an ITIN helps to ensure compliance with U.S. tax laws, as individuals can report income and claim any eligible tax benefits or refunds.

In contrast, the W-9 form is utilized by U.S. persons and businesses to provide a taxpayer identification number to parties that will report certain types of income. The SS-5 form is used to apply for a Social Security card and is not applicable for tax filing purposes without the issuance of a Social Security number. The SS-9 form is not a standard IRS form and does not apply in this context. Thus, the W-7 is the appropriate choice for aliens in this situation.