Sole proprietors may want to obtain an EIN in order to avoid using their Social Security number for business purposes. Banks usually insist on providing EIN details for opening a bank account in the name of your business. Sometimes, your investors and vendors may also ask for your EIN.

You may need a copy of the EIN letter from the IRS on various occasions to confirm your tax ID to your bankers, financers, and vendors. The IRS issues this letter in Form CP 575 within eight (8) to ten (10) weeks of assigning you an Employer Identification Number (EIN). If you lose or misplace the original confirmation letter, you can request the IRS for a verification letter, which would for all purposes, substitute the original letter or certificate.