Employers and other organizations must obtain an employer identification number (EIN) to identify themselves for tax administration purposes, such as starting a new business, withholding taxes on wages, or creating a trust. Entities apply for an EIN by filing IRS Form SS-4. Page two of the form advises whether an applicant needs an EIN.
Other entities that need an EIN include corporations, partnerships, estates, trusts, state or local governments, and churches and other nonprofit organizations. Unincorporated entities (sole proprietorships) that establish a retirement plan or that file certain tax forms will also need an EIN for filing the relevant forms.
The IRS does not charge for obtaining an EIN and has sought to simplify the application process. Taxpayers may apply by mail, by fax, or online. International applicants may also apply by phone. In all cases, if the IRS determines that the applicant needs an EIN, the IRS will issue the EIN and transmit it to the taxpayer in the same manner as the application was made.
Applications by mail generally take four weeks, the IRS indicates, once the SS-4 is properly and completely filled out. Entities located in the U.S. or a U.S. territory can apply online. For online applications, the IRS validates the information and issues the EIN immediately. The IRS notes that the principal officer or other relevant party must have a valid taxpayer identification number, such as a Social Security Number, to use the online application process. The IRS will respond to a completed fax application within four business days, if the applicant provides a fax number.
Filing without EIN
The IRS states that it will only issue one EIN per day per responsible party, regardless of the means of applying. If the taxpayer needs to file a return but lacks an EIN because of this limitation, the IRS advises that the taxpayer should attach a completed Form SS-4 to the completed and signed tax return. The IRS will assign an EIN and then process the return.