In the real estate business, a buyer agent refers to an agent or broker that represents the buyer in a transaction. This can include buyer agents from traditional listing firms, as well as buyer agents from EBA (Exclusive Buyer Agent) firms, which represent the interests of the buyer in all transactions. http://portal.hud.gov/hudportal/documents/huddoc?id=DOC_12164.pdf
Also See EBA, or Exclusive Buyer Agent.