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. Form 8594 is an Internal Revenue Service (IRS) form that provides a structured way to allocate the purchase price of a business among different asset classes. Learn how to file form 8594 and when to file. The tax professional who comes into contact with such a situation should consider the need to file Form 8594, or to revise the valuation of specific assets.