Per IRS instructions for Form 8959 must be filed if:
- Your Medicare wages and tips on any single Form W-2 (box 5) are greater than $200,000.
- Your RRTA compensation on any single Form W-2 (box 14) is greater than $200,000.
- Your total Medicare wages and tips plus your self-employment income, if any (including the Medicare wages and tips and self-employment income of your spouse, if married filing jointly), are greater than the threshold amount for your filing status in the Threshold Amounts for Additional Medicare Tax chart.
- Your total RRTA compensation and tips (Form W-2, box 14) (including the RRTA compensation and tips of your spouse, if married filing jointly) is greater than the threshold amount for your filing status in the Threshold Amounts for Additional Medicare Tax chart.
- Your Medicare wages include your wages and tips from Form W-2, box 5; your tips from Form 4137, line 6; and your wages from Form 8919, line 6.
- Your self-employment income includes amounts from Schedule SE (Form 1040), Part I, line 6. But negative amounts shouldn't be considered for purposes of Form 8959.
If none of these situations apply and if you are married make sure that when you entered your income you allocated it to the correct person. Sometimes if you allocated all forms to the same person, the additional tax will kick in.