An asset purchase agreement (APA) is a written legal document that formalizes purchasing a business or substantial commercial asset. 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.Purchasing A Business Or Business Assets. An asset purchase contract defines the assets and liabilities to be sold when one company purchases another. When a client is considering purchasing all or some assets of another company, we work with them to get an understanding of what it is they are buying. 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. All liabilities and obligations arising out of operation of the Business or the use or ownership of the Acquired Assets from and after the Effective Time. Before you buy an existing business, find out if the business owes any Texas taxes.