An asset purchase agreement (APA) is a written legal document that formalizes purchasing a business or substantial commercial asset. 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.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. Parties and Recitals. An asset purchase agreement (APA) is a legally binding agreement used when a company wishes to buy or sell specific assets of another business. This guide will break down the ins and outs of asset purchase agreements for multiple owners, making this complex legal topic more digestible and actionable.