[sgent]

You have to have a social security number so citizen, current or former resident or work visa holder.

[robocat]

Not former. From https://www.treasurydirect.gov/indiv/research/indepth/ibonds...

  Yes, if you have a Social Security Number and meet any one of these three conditions:
  - United States citizen, whether you live in the U.S. or abroad
  - United States resident
  - Civilian employee of the United States, no matter where you live