You (or the purchaser or transferee) must complete Form CBS-1, Notice of Sale, Purchase, or Transfer of Business Assets. This is a sample asset purchase agreement, for the sale of the seller companies' corporate assets to a buyer company.However, you can sign an asset purchase agreement with a buyer to sell all your sole proprietorship's assets. To sell a business in Illinois, you'll need various legal documents, including a bill of sale, asset purchase agreement, and non-disclosure agreements. Buying or selling company assets? Use this Asset Purchase Agreement to finalize the terms of the transaction.