Form 8959 Additional Medicare Tax

Several clients have asked me this year, “What is this tax from Form 8959 on my 1040.” And I spend several minutes on the phone or writing a letter to the client explaining the form, the tax, and how it is calculated. The tax is Additional Medicare Tax authorized under the American Care Act (ObamaCare) and is assessed on all income subject to Medicare tax; wages, tips, self-employment income, basically all earned income. Passive income (interest and dividends) is not subject to this tax. Non-cash wages; i.e. fringe benefits, are subject to this tax. Example, taxpayers who receive the use of a vehicle for work and are taxed on the personal use of the vehicle (reported on their W-2). The personal use is subject to this tax if total gross income exceeds the threshold.

An individual is liable for Additional Medicare Tax when the individual’s wages, compensation, or self-employment income (together with that of his or her spouse if filing a joint return) exceed the threshold amount for the individual’s filing status:

Filing Status


Married Filing Jointly (MFJ)


Married Filing Separately (MFS)




Head of Household(with qualifying person)


Qualifying Widow(er) with dependent child



There are no exceptions for resident aliens or U.S. Citizens living abroad, they are subject to the tax even if over sea’s income is excluded from income tax.

Employers must withhold the tax from wages when an individual in their employ has earned income in excess of $200,000 in a calendar year without considering the individuals filing status or wages paid by another employer. And individuals who are self-employed or are employed by two or more employers and whose wages will not exceed the threshold from anyone employer but in total will exceed the threshold; should make estimated tax payments for the Additional Medicare Tax. The threshold amount for this purpose is $200,000. However the taxpayer cannot request the employer withhold additional funds specifically for this tax. But the employee may request additional withholding for income taxes which will be available on Form 1040 to apply to the tax there.

The additional tax is included in the total Medicare tax withheld from the employee’s wages for reporting purposes and is included in the Medicare number of Box 6 on the W-2.

The tax rate is 0.9% (.009) on income in excess of the threshold so for a couple filing MFJ with gross taxable income of $300,000 the tax 0.9% of $50,000 or $450.00. An individual filing single with gross income of $300,000 the tax is $900.

Calculating the tax is a three step process:

1.)    Calculate Additional Medicare Tax on any wages in excess of the applicable threshold for the filing status, without regard to whether any tax was withheld.

2.)    Reduce the applicable threshold for the filing status by the total amount of Medicare wages received, but not below zero.

3.)    Calculate Additional Medicare Tax on any self-employment income in excess of the reduced threshold.

An example is a single filer (C), has $130,000 in wages and $145,000 in self-employment income. C’s wages are not in excess of the $200,000 threshold for single filers, so C is not liable for Additional Medicare Tax on these wages. Before calculating the Additional Medicare Tax on self-employment income, the $200,000 threshold for single filers is reduced by C’s $130,000 in wages, resulting in a reduced self-employment income threshold of $70,000. C is liable to pay Additional Medicare Tax on $75,000 of self-employment income ($145,000 in self-employment income minus the reduced threshold of $70,000).

The method is the same for other filing statuses with the threshold increasing or decreasing depending on the filing status as shown in the above table.

The additional tax withheld is included in box 6 of the W-2; Medicare tax withheld and is added to the income tax withholding amount from box 2 of the W-2 when reported on Form 1040. The tax is calculated again using total income on Form 8959. The tax amount is shown on Form 1040 under the Taxes section increasing the filer’s tax liability and the tax paid through withholding paying the tax.

I end with this is a tax intended to fund Medicare services and ObamaCare with a tax on high income filers and is a separate tax on previously taxed income; essentially double taxation of income. A rare occurrence in American taxation as it has been policy to avoid double taxation. Will this tax be rescinded under the changes proposed by the Trump administration has yet to be seen? Typically taxes once enacted stay even when the purpose they were enacted for have long since past.

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