For 2012, the maximum taxable earnings amount for Social Security (OASDI) taxes is $110,100. There is no limit on taxable earnings for Medicare’s Hospital Insurance (HI) taxes. The Social Security tax rate for employees is 4.2 percent and is set to expire December 31, 2012. The Social Security tax rate for employers is 6.2 percent and is set to expire December 31, 2012. The Medicare tax rate is 1.45 percent for employees and employers and also set to expire December 31, 2012. Social Security’s Old-Age, Survivors, and Disability Insurance (OASDI) program and Medicare’s Hospital Insurance (HI) program are financed primarily by employment taxes. Tax rates are set by law (sections 1401, 3101, and 3111 of the Internal Revenue Code) and apply to earnings up to a maximum amount for OASDI. Note: In 2013, the social security wage base will increase to $113,700. For other 2013 tax rates, please refer to the HR Support Center alerts se ction or consult with a CPA.