Consider a non-US citizen who is married to a US citizen. The non-US citizen is not a US resident for income tax purposes, but the couple have elected under section 6013(g) of the Internal Revenue Code for the non-US citizen to be treated as a resident, to enable the couple to file a joint tax return.
The non-US citizen now wishes to open a bank account in a country other than the US. The bank asks whether she is a US citizen or permanent resident, and it asks questions about how much time she spends in the US. (All of her time spent in the US, however, was in G-4 status, so it does not count for the purpose of the substantial presence test.) It does not ask whether she has filed US income tax forms nor whether she is a tax resident for any other reason.
Is the bank required to treat her as a US person? The research I've done suggests that it is not, because the 6013(g) election applies only to chapters 1 and 24 of the Internal Revenue Code, while FATCA is in chapter 4. However, some things I've seen suggest a different interpretation, namely that the election to be treated as a US resident for the purpose of income taxation means that the person is a "US person" for the purpose of FATCA.
Which interpretation is correct?