Thanks for your input — you’re absolutely right that Massachusetts calculates a tentative tax on all income and then prorates it using the MA-sourced income divided by federal AGI, via Schedule R/NR.
However, in my case, that proration ratio is 0 ÷ $343,415, because I’m a Florida resident, never physically worked in Massachusetts, and all my income is sourced outside MA — including capital gains, which were entirely from investments with no MA nexus. As a result, my MA taxable income is zero, and my final tax due is also zero, as confirmed by the MA DOR guidance on nonresident returns.
This aligns with MA Form 1-NR/PY instructions (p. 24) which state:
“If you did not have any Massachusetts income, your Massachusetts taxable income will be zero, and no tax is due. If Massachusetts tax was withheld, you should file to claim a refund.”
I appreciate your engagement — these nonresident sourcing rules are tricky even when the software gets them wrong (as TurboTax initially did in my case).
