I just realized that my employer has not been withholding FICA taxes from my paycheck for almost 7 years. They withhold state and federal income taxes, but they have not withhold FICA. It is worth noting I am a W2 employee. So this is not an issue where my employer accidentally classified me as independent contractor. I get a W2 each year. So, boxes 1, 2, 16 and 17 in my W2 have numbers in it, but boxes 3, 4, 5, 6 and 7 are blank. I logged into ssa.gov and my statement shows zero in “Earnings taxes for social security” for many years. I discovered this lack of FICA and have informed my employer. My employer agrees this was a mistake and that I should be paying FICA and they will start deducting FICA going forward. But they are still figuring out how to solve this problem of unpaid FICA. Based on this multi year oversight, I do not trust that my employer/HR/payroll knows what it is doing. As this is a mistake that has been happening for almost 7 years, the amount of money owed to the government is a lot.
Will I need to pay all of these 7 years of unpaid FICA either to my employer or the government this year?
Is my employer allowed to reduce my paycheck to payback all of these 7 years of unpaid FICA?
While there are some professions that do not pay FICA taxes, it seems that your employer has confirmed that there should be FICA taxes withheld and that you are not exempt.
If you employer made a mistake on your W2, it is your employers responsibility to file a correction. They would need to correct it was far back as the error occurred. And yes, they would be allowed to recoup your share of the FICA depending on your state.
I found this article that is very close to you situation with some additional resources listed: Employer Failed to Withhold FICA