@gb1 wrote:
Unique situation -- one has a higher income, other has lower income.
There's nothing unique about that. It's quite common. But having different levels of income is usually a reason to file jointly. You have to try it both ways and see which works out better, but you have to look at your overall total tax, not just whether you pay NIIT. Filing separately usually results in higher tax. It could increase your tax in other ways by more than you save by avoiding NIIT. And remember that if you file separately you have to either both itemize deductions or both take the standard deduction. You're not allowed to itemize on one return and take the standard deduction on the other.
If you are in a community property state, the difference in incomes might get erased by the community property rules.
