what amount is subject to additional medicare tax withholding?
2016 Social Security and Medicare Tax Withholding Rates and Limits. 1  For 2016, the maximum limit on earnings for withholding of Social Security (Old-Age, Survivors, and Disability Insurance) Tax remains $118,500.00. 2  There is no limit on the amount of earnings subject to Medicare (Hospital Insurance) Tax. The Medicare Tax Rate applies to all taxable wages and remains at 1.45 percent with the exception of an âadditional Medicare Taxâ assessed against all taxable wages paid in excess of the applicable threshold (see Note).