2013 Additional Medicare Tax
In 2013, the IRS added an Additional Medicare Tax which an employer must withhold from wages it pays to an individual in excess of $200,000 in a calendar year, without regard to the individual's filing status or wages paid by another employer.
An individual may owe more than the amount withheld by the employer, depending on the individual's filing status, wages, compensation, and self-employment income. In that case, the individual should make estimated tax payments and/or request additional income tax withholding using Form W-4, Employee's Withholding Allowance Certificate.
If an individual owes less than the amount withheld by the employer, the employee will claim credit for any withheld Additional Medicare Tax against the total tax liability shown on their individual income tax return (Form 1040).
For more information, please visit the IRS website at the link below:
Questions and Answers for the Additional Medicare Tax