In simple terms, a sole proprietorship refers to a business which is not incorporated and which has only one owner.
When a sole proprietor has an employer identification number (EIN), it would seem to be common sense that the proprietor would put that EIN on the Schedule C for the proprietorship. Not so fast -- especially of the sole proprietorship is a single-member LLC taxed as a sole proprietorship.
Question: I am a co-owner in a partnership. The partnership has an EIN. We have now decided to form an LLC but will continue to be taxed as a partnership. Do we need a new EIN for the LLC? Answer: No, you can keep your existing EIN.