# 19.243 Application for employer identification number.(a) *Use Form SS-4.* The proprietor must obtain an employer identification number (EIN) by filing an application with the Internal Revenue Service (IRS) on Form SS-4. Form SS-4 is available from Internal Revenue Service Centers, from IRS District Directors, the IRS Web site at *https://www.irs.gov,* or from TTB's National Revenue Center. The proprietor may file this form with IRS by mail, telephone, or fax by following the instructions on the form.(b) *Time limit.* If the proprietor has not already received, or applied for, an EIN at the time that the first return on form TTB F 5000.24, Excise Tax Return, is filed, the proprietor must file such application for an EIN not later than seven days from the date of filing the TTB F 5000.24.(c) *One EIN only.* Each proprietor must obtain and use only one EIN, regardless of the number of places of business for which the proprietor is required to file a tax return under this subpart.(26 U.S.C. 6109)[T.D. TTB-92, 76 FR 9090, Feb. 16, 2011, as amended by T.D. TTB-196, 89 FR 87939, Nov. 6, 2024]