While waiting for a response from the IRS on how to file foreign retirement accounts, I learned from the The Isaac Brock Society that this is done with Form 3520. I’ve never seen or heard of this form before, so I looked it up on TurboTax, which states:
Form 3520 is not included in TurboTax because it is not part of your income tax return, and you do not file it with your income tax return. It is a separate return. You can download the form and instructions from the IRS web site using the links below, fill it out, and mail it to the address in the instructions.
The form looks rather complicated. When I have time, I’ll try to fill it out and then I’ll contact the IRS to see if I did it right.