A W-3 form is a tax form used by employers to report combined employee income to the Internal Revenue Service (IRS) and the Social Security Administration. It is also known as the Transmittal of Wage and Tax Statements form. Employers who send out more than one Form W-2 to employees must complete and send this form to summarize their total salary payment and withholding amounts. Employers who send out a single Form W-2 do not need a separate form to tally the total amounts, as they’re displayed on their single employee’s Form W-2. Every employer required to file a Form W-2 must file Form W-3. The form reports the total employee wages, taxable wages, and taxes withheld throughout the year. The W-3 form is sent to the Social Security Administration (SSA) for proper filing. Employers must file both W-2 and W-3 forms with the Social Security Administration by January 31 of every year.