Form 8594 must also be filed if the purchaser or seller is amending an original or a previously filed supplemental Form. 8594 because of an increase or decrease.Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity. Today's goal is to help you understand the importance of IRS Tax Form 8594 in preparing for sale of your business to a third party… Enter your name and taxpayer identification number (TIN) at the top of the form. Then check the box for Purchaser or Seller. A taxable asset purchase allows the buyer to "step up," or increase, the tax basis of the acquired assets to reflect the purchase price. For a list of forms and schedules available in ATX, please click on federal forms or select a state.