To get a SS number you would have to start an immigration process that can be long and costly. Getting an ITIN, although it takes time is probably the easiest and the IRS does not charge for it. Per the IRS Form W7 Instructions, you may need an ITIN if you’re a:
- Nonresident alien claiming a tax treaty benefit
- Nonresident alien filing a U.S. federal tax return
- Resident alien filing a U.S. federal tax return
- Dependent or spouse of a U.S. citizen/resident alien
- Nonresident alien student, professor or researcher filing a U.S. federal tax return or claiming an exception
- Dependent or spouse of a nonresident alien U.S. visa holder
Instructions for Form W-7
