Consumers and firms often need to employ agents, for example to give professional advice that the principal needs in order to make a good decision. The problem is that there may be asymmetric information and the agent may not act in the principal’s best interests. For example, you may go to an estate agent to buy a home, precisely because you do not know much about the local housing market. But the agent may conceal information about a property, without your realising, and may do so in order to achieve a speedy sale. In a firm, the principals may be the shareholders, who employ the management to run the business, or the management, where the agents are the employees lower down the ladder. The agents may choose to run the business in a way that takes little effort, where the shareholders would prefer an energetic search for profit. The latter may be unable to get the information needed to show that this is happening.