Here Are The Tax ID Number(s) & Other Registrations Required When Starting a Business All Businesses need a Business Tax ID Registration & an Assumed Business Name If you are a retailer or wholesaler, you will need a State Sales Tax ID Number , & a Business Tax ID Registration . If you hire workers, you will need a Federal Tax Id Number (EIN) & EIN Employer Identification Number , & a Business Tax ID Registration . Corporations and LLCs need a Federal Tax Id Number (EIN) & a Business Tax ID Registration . Partners need a Federal Tax Id Number (EIN) a Assumed Business Name & a Business Tax ID Registration . Sole Owner/Proprietors may get and use a Federal Tax Id Number (EIN) as a Business Tax ID Number & a Business Tax ID Registration .Instead of filing an Assumed Business Name, you can incorporate or form an LLC & You will not need an Assumed Business Name