To protect yourself from potential tax liability when you buy, sell, or discontinue a business, you must obtain a Certificate of Tax Clearance from the Arizona State Board of Equalization. If you buy a business, you must adjust the purchase price by the amount due on the existing business. Be sure to cancel your account and return the Seller’s Permit when you discontinue business to avoid further tax liability from future owners, your entire deposit or any unused portion will be returned.