You are required to report all sales of businesses to the Illinois Department of Revenue. Disclosure of this information is REQUIRED.A sale of assets may be partial or complete. To sell a business in Illinois, you'll need various legal documents, including a bill of sale, asset purchase agreement, and non-disclosure agreements. When selling your business, you'll need to decide between an asset sale or a stock sale. It's important to understand how asset sales work. Use Form 4797 to report: The sale or exchange of property. The involuntary conversion of property and capital assets. The seller should be ready to provide detailed information about the business's assets, liabilities, revenues, costs, and customer base, among other things. If you need additional information, you may call our Chicago office weekdays between a.m.