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. Further, the parties should agree to file a supplemental Form 8594 to reflect any such increase or decrease. Line 4: Enter the fair market value for each asset class and specify the portion of the total sales price allocated to that class. Learn how to file form 8594 and when to file. Local business tax categories cover various types of businesses and the associated cost of receipt for each.