" as a NRA, if you are not required to pay tax on the gain, I wouldn't beleive that a loss will get you a benefit. "
That's exactly how I thought too. However, notice that an NRA is potentially (depending on the country of current residency) subject to taxes on the capital gains where they are tax resident for the year under consideration. So, in this example, the NRA would have been subject to taxes in 2023 on the capital gains (if there were any, besides the losses) in their country of tax residency. But then, because the NRA became tax resident in the US in 2025, should the losses sustained in 2023 just disappear into void? I think the NRA is a victim of the situation here. Maybe if the NRA moves back to their home country or the country they were tax resident while incurring the losses in a future year, say 2028, they could readjust the potential capital gains in that year against these 2023 losses.
