Thanks @pk, very helpful. You are correct on #1. On #2, that is how I read the second Pub 519 rule I cited in my last post, but for others reading this, I don't think the 'resident of only one country at a time' holds true in general. For example, we could have moved to a country with the same residency rules as Ireland but that does not have a DTA with the US (hence no residency tie-breakers). But back to our case, I think you are correct that we can't be residents of both the US and Ireland at the same time.
If it's of interest to you, Split Year Treatment does not affect Irish residency, only the way employment income from outside Ireland prior to moving to Ireland is treated for tax purposes. In other words, Ireland does not have a dual status as the US does. Thus, putting it all together:
- US resident for 2025 under domestic rules? Yes (dual status available).
- Irish resident for 2025 under domestic rules? Yes (dual status not available).
- Do Ireland and the US have a tax treaty with residency tie-breakers? Yes.
- Resident of which country under the tie-breakers? Ireland (given current circumstances).
- Pub 519 'Effect of Tax Treaties' rule: 'treated as a nonresident alien in figuring your U.S. income tax.'
This is where I stand at this point. Thanks for helping me through these difficult questions!
All the best.
