Complete Part III and file a new Form 8594 for each year that an increase or decrease in consideration occurs. Enter your name and taxpayer identification number (TIN) at the top of the form.Then check the box for Purchaser or Seller. Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity. Learn how to file form 8594 and when to file. The seller and the buyer each use Form 8594 to allocate the assets among seven asset categories. Allocation is based on the fair market value. How to fill out Form 8594?