What is a company TIN?
A company Tax identification Number (or “TIN") is a number assigned to you for the purpose of administering company taxes and VAT. It is most often allocated by the tax authorities within your country - as opposed to your company registration number, which is issues by the company registry.
The actual word used to identify this number varies between countries. If your are unsure of what your company TIN number is then please see the resources below.
TIN / VAT number outside of the US. (Extensive Wikipedia article covering TIN number)
TIN Number in the United States (IRS Website)