It is very common to receive a request for your EIN. Because the EIN is associated with your business and not with your personal records, it is fine to provide it. You may need to provide it to your bank to open a business account. You will also have to provide it to businesses who request it because they will need to report payments made to you to the IRS. You should be careful with the number, but you don't have to keep it secret.

Justin, There are occassionally time where you will be required to use your EIN number to prove that you are a representative of your business. While identity theft of EINs is not as common as SSNs, it can still happen so it's important to be vigiliant about safeguarding your ID. I would be suspiscious if this company is phishing for unsolicited information about your business. If you do not have a business need to interact this with this company and they are contacting you out of the blue, I would caution against providing them with any information about your company. On the other hand, if this company will be having financial interactions with you (say if they are a supplier for your business) then there is likely a legitimate business need for them to inquire about your EIN.

Can you provide the company with a copy of your business registration with your state or county? That information is public record and many states have it on their web sites. You can easily print a copy to give to the company. If they require an EIN, then, as Nicole mentioned, be sure the request is legitimate.

We've been asked for W-9's before, which simply proves that you're paying taxes correctly on the orders which you're taking. It a pretty normal request to receive if you're working with a larger organization, but I'd frankly be suspect if it's another really small outfit and you haven't had any sales with them as of yet.