In December 2010, the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010 reduced the employee social security tax rate to 4.2% for 2011 and left the employer tax rate at 6.2%.
Employees will continue to pay 4.2% in social security tax during the first two months of 2012. This means that employees will pay 4.2% on wages paid in January and February 2012 up to the $110,100 wage base.
The late enactment is making it difficult for many employers to correctly calculate social security tax withholding for the first payrolls of 2012. Therefore, the IRS is asking employers to update their payroll systems as soon as possible, but not later than January 31, 2012. For any social security tax over withheld during January because of the rate change, employers should make an adjustment in employees’ pay as soon as possible, but not later than March 31, 2012. Please review [IR-2011-124, 12-23-11; www.irs.gov/newsroom/article/0,,id=251650,00.html].