Even if a consultant isn't going to have employees, they may need an EIN (employer identification number). The EIN is a nine-digit number issued by the IRS and used for tax and reporting purposes. Most banks and other financial institutions require an EIN before opening business accounts. After that, you may need to take additional steps, such as obtaining an employer identification number (EIN), obtaining the necessary licenses and permits for your company, and opening a business bank account to keep your personal funds separate from those of the company.
The IRS rules on EIN requirements are not directly related to whether you are a consultant or not.