Which form must be completed to apply for an employer identification number (EIN)?

To apply for an employer identification number (EIN), the appropriate form to complete is Form SS-4. This form is specifically designed by the Internal Revenue Service (IRS) for businesses and entities that wish to obtain an EIN, which is necessary for various tax-related functions. The form collects essential information about the entity applying for the EIN, including its legal structure, reason for applying, and the identity of the principal officer or owner.

The other forms listed serve different purposes. Form W-2 is used by employers to report wages paid to employees and the taxes withheld. Form 1040 is the individual income tax return that taxpayers file to report their annual income and taxes owed. Form 1099 is used to report various types of income other than wages, salaries, and tips, such as independent contractor earnings. Thus, none of these other forms would be appropriate for applying for an EIN.