This article will discuss the law applicable to lease-options and lease-purchases including the overlap with the law of executory contracts. 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.Parties and Recitals. 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. An asset purchase agreement is a written legal instrument that formalizes the purchase of a business or significant business asset.