EIN for a sole proprietor

Not necessarily. They may use their Social Security number rather than an EIN for federal tax reporting.

A sole proprietor must, however, use an EIN if the business has any employees or maintains a qualified retirement plan.

A sole proprietor may need an EIN to open a business bank account. An EIN can also be used in place of a Social Security number by an independent contractor for purposes of Form 1099-MISC reporting.