Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity. 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. This comprehensive guide on IRS Form 8621 delves into PFICs, filing requirements, penalties, and more. I Within 30 days following the Effective Time, BUYER will deliver to SELLER an IRS Form 8594 prepared in a manner consistent with the Tax Allocation. Learn how to file form 8594 and when to file.