Employers use IRS Form W-2, Wage and Tax Statement, to report an employee's earnings and withholdings to the Internal Revenue Service, Social Security Administration and state and local taxing authorities. Employers are required to file a W-2 form for every employee who earns $600 or more during the calendar year or from whom Medicare, Social Security or income taxes have been withheld from gross income earned during the calendar year.
Purpose and Use of Control Numbers
Control numbers are unique numbers assigned by an employer or its payroll department to identify individual W-2 Wage and Tax Statements. Employers may, but are not required to, use Box D to list an employee's control number. Many times Box D is left blank. It is okay if you receive a W-2 with a blank Box D. Box D is for the employer's convenience only.