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.Who Must File Form 8594? Both the seller and purchaser of a group of assets that make up a trade or business need to file Form 8594. 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. Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity. The Tax Court held that the taxpayer was required to take the assumption of the liability into income despite no corresponding deduction to the taxpayer.