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. Learn how to file form 8594 and when to file. 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. Awards shall be made under such regu lations as the said Secretaries shall severally prescribe and such regulations shall, insofar as practicable, be of uni.