An asset purchase agreement is the legal document that will govern the transfer of ownership of a business's assets from the seller to the buyer. An asset purchase agreement (APA) is a written legal document that formalizes purchasing a business or substantial commercial asset.Parties and Recitals. An Asset Purchase Agreement is a legally binding contract between a buyer and a seller that details the terms and conditions of the sale of a business's assets. Before you buy an existing business, find out if the business owes any Texas taxes. An asset sale is a type of business transaction in which a buyer purchases all, or part of, a selling business' assets. An APA, or Asset Purchase Agreement, is a contract in which a buyer and seller agree to the transfer of ownership for an asset at an agreed price. When you purchase or sell an asset, you must retitle all property in the new owner's name. This includes leases and equipment titles.