Verifying employee Social Security numbers
We recommend that you verify your employees' Social Security numbers (SSNs) with the Social Security Administration (SSA) before you create your W-2 forms. If you submit incorrect names and SSNs on your W-2 forms, the SSA may fine your company or reject your file completely. SSN verification is a free service available from the SSA.
Before you verify Social Security numbers with the SSA, you must have a Requester ID Code from the SSA. See Appendix C: Government resources.