A Tax ID Number, or Employer Identification Number, is a nine digit number used by the Internal Revenue Service for tax purposes. Corporations are required to get a TIN from the IRS to uniquely identify their business. If you purchase a corporation, you would likely not be required to get a new TIN.
A TIN, or EIN, is a number assigned to businesses and organizations by the IRS. Corporations use the number to file tax returns and to communicate with other government bodies. For example, if the corporation is a public entity, the corporation uses its TIN to file required documents with the Securities and Exchange Commission. TINs are used to get government contracts, open business bank accounts and apply for business licenses. The form of the EIN is xx-xxxxxxx.
When You Need a New TIN
When you purchase a corporation, you are required to get a new TIN if any of the following circumstances apply to the corporation at the time of purchase: the corporation has received a new charter from the Secretary of State; the corporation was created as a result of a statutory merger; the corporation is a subsidiary of a parent corporation; or if you change the corporation to a sole proprietorship or a partnership.
When You Don't Need a New TIN
You won't need to get a new TIN for your corporation if you are a division of a corporation or if you use an existing EIN for a surviving corporation after a corporate merger. If you change the location of the corporation or change the company name, you wouldn't be required to get a new EIN because the structure of the company remains unchanged. You can also change the tax status of a corporation to an S corp without getting a new TIN.
How to Get a TIN
If you need to get a new TIN as a result of your purchase, the IRS offers an online form which will give you an instant EIN. The online EIN Assistant (see Resources) is the IRS's preferred TIN application method. The interview style form guides you through the application process in about 20 minutes and provides you with your EIN at the end of the process. You'll be able to save a PDF with your number or print out a copy of the form.