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.Line 1: Enter the name, address, and Tax Identification Number (TIN) of the other party (either the purchaser or seller). Both the purchaser and seller are required to file Form. 8594. (2). Each party, Seller and Purchaser, shall use the Allocated Amounts on IRS Form 8594. Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity.