The over-payment would be entered on the applicable line of Form 1040 and, assuming the employee did not owe any other Federal taxes, would be refunded to the employee. The employers who each paid $4,340 will not get a refund, since they are not aware that the employee overpaid in aggregate for the year. The government keeps the $818.40 overage. Even if the employers become aware of the overpayment, there is no method to claim the overpayment. Several occupations are exempted from the current cap with a far lower cap, such as food service employees and domestic help employees. For the year 2014, the cap was $6,500 in wages. Since 1998, the SSWB has been: (*) The maximum employee share in 2011 is reduced to $4,485.60, but the maximum employer share remains at $6,621.60. The maximum employee share in 2012 is reduced to $4,624.20, but the maximum employer share remains at $6,826.20. Effectively, this was a 4.2% rate charged to the employee, and 6.2% rate to the employer. This resulted in an approximately 40/60 split but reduced the total contribution. See here for a complete historical list of the Social Security Wage Base. (**) Since 1990, the employer & employee share has usually been 6.2% each for a 50/50 split of the 12.4% combined total. The changes shown below applied In 2011 and 2012 when the rates were temporarily lowered to 4.2% for the employee (but remained at 6.2% for the employer). In 2013, the employee rate returns to 6.2% for a 50/50 split with the employer and a higher Maximum Contribution. For self-employed people, the 2013 guidance from SSA indicates the full rate OASDI is 12.4% for 2013. See footnote a. at 2013 SSA.gov link. Returning to the traditional 6.2% OASDI employee share for 2013 effectively reduces take home pay by 2% and increases the maximum OASDI contribution by the same amount, returning it to traditional levels. The dip in the maximum OASDI contributions for 2011 and 2012 causes the 2013 rate to appear as a spike, when in fact it is a return to the levels imposed in the years 1990 through 2010. Note that although self-employed individuals pay 12.4%, this is mitigated two ways. First, half of the amount of the tax is reduced from salary before figuring the tax (you don't pay Social Security tax on the tax your employer pays for you.)