If an employer fails to provide the current-year Form W-2 by January 31, the employee should contact the employer or payer, according to the Internal Revenue Service. If the form is not provided by February 14, call the IRS at 800-829-1040 for assistance.
The IRS can attempt to contact an employer on behalf of an employee. The IRS explains, that If the W-2 is not provided in time to file a tax return, the taxpayer can use Form 4852 as a substitute W-2. Income and tax withholding are entered on this form. According to Bankrate, estimates with an explanation of how they were determined may be acceptable, if the W-2 is not provided. If the W-2 is provided late, and shows different amounts than those estimated, an amended tax return, Form 1040X, can be filed.
The 4852 cannot be filed before February 15 even if the employer is bankrupt or out of business. If the missing W-2 is for a prior year, the taxpayer can request a "Wage and Income Transcript" online at the IRS website. The IRS makes this information available free of charge, for up to ten years. It is not a complete W-2. The taxpayer can request a copy of a prior W-2 by using tax Form 4506. The Social Security Administration can also provide a copy of the W-2 to resolve SSA-related discrepancies.