Why do I have to get a Social Security Number to file a U.S. income tax return (USCs)?

U.S. citizens who meet certain income thresholds (currently about US$10,000 for individuals not filing married-jointly; and about US$20,000 for individuals filing married-jointly) who reside outside the U.S. have no choice but to obtain a SSN in order to file tax returns under U.S. law.  See the specific income thresholds for who is required by law to file a U.S. tax return, here.

As explained in a previous post, under U.S. tax jargon a “taxpayer identification number” (TIN) is a broad definition and includes all of the following, which are TINs –

1. U.S. Social Security Number (“SSN”) in the case of certain individuals (USCs, LPRs and those who have permission to work in the U.S. under a particular visa);
2. “Individual Taxpayer Identification Numbers” (ITIN) in the case of other individuals who are not USCs or LPRs and not otherwise eligible for a SSN (another post will explain how ITINs are obtained);
3. Employer identification numbers (EINs) for certain entities, such as corporations, partnerships and trusts.

Most importantly, the regulations specifically require a U.S. citizen to obtain a SSN to use it as the “taxpayer identifying number.”  The relevant regulations provides that

(A) Except as otherwise provided in paragraph (a)(1)(ii)(B) and (D) of this section, and § 301.6109-3, an individual required to furnish a taxpayer identifying number must use a social security number. 

The exceptions referred to above where a SSN is not required in these regulations are principally for individuals who are not U.S. citizens and not eligible to obtain a SSN.  See, Social Security Numbers for Noncitizens as published by the Social Security Administration (“SSA”).  Any U.S. citizen is eligible for obtaining a SSN.  For information regarding applying for a SSN, see the SSA website.

Ironically, it can be very difficult (nearly impossible in some cases) for USCs who have spent most (if not all) of their lives outside the U.S.; considering the methods of proof required by the SSA when the Application For a Social Security Card (Form SS-5-FS) is submitted.

Once a SSN is obtained, the USC is required to complete IRS Form W-9 vis-a-vis third parties providing them proof of their status and SSN.

More will be discussed in later posts about how to get a SSN overseas from a U.S. Embassy and some Consulate offices.  Also, see, The Catch 22 of Opening a Bank Account in Your Own Country – for USCs and LPRs.