: Current mailing address for the worker. Wages and Tax Withholdings (Boxes 1–10)
: The federal tax ID assigned to the employer.
The 2012 Form W-2, Wage and Tax Statement, follows a standardized text structure for identifying information, income boxes, and statutory codes. For that tax year, the Social Security wage base was capped at . Identifying Information (Boxes a–f)
: Optional internal tracking number used by some employers.