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.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. Question about the form itself, and accounting for an assumed liabilitie. According to section 1060 of the Internal Revenue Code, the IRS requires that you fill out and file Form 8594 when you're buying or selling a business.