成屋履約保證與不動產仲介市場——訊號顯示理論的解說與應用

Signaling Theory, Existing-Housing Contract Warranties and Real Estate Brokerage Market

本文從訊息經濟學中訊號顯示理論（signalling）的概念來分析成屋履約保證的經濟意義。由於不動產仲介市場為一訊息不完全市場，為了減低市場訊息不對稱的問題，業者可透過保證（warranties）的方式，告知買方有關產品或勞務的品質，提供在交易之後某段時間內之品質瑕疵的擔保，買方或許較能確信業者不太可能對有問題的產品（勞務努力的結果）還提出保證，如此較願確信它是一品質佳的產品（勞務）。這種長期所建立的商業信用（credible），亦就是所謂訊息顯示的作用。實際上，成屋履約保證可能就具有這種功能，成屋履約保證不見得真能夠“保證”交易沒有問題，但是其可能傳達給消費者“選擇具有推出成屋履約保證的業者其糾紛將較少”這項訊息，以吸引消費者。應用訊號模型分析，我們可以得到，在分離均衡（separating equilibrium）之下，在買方有一主觀機率認為提出成屋履約保證的公司為好的公司之機率為一的情況下，如果仲介業為類型g（提出保證之成本較低）則此仲介業將會選擇採用成屋履約保證，如果他是為類型b仲介業（提出保證之成本較高），則將會選擇不採用成屋履約保證。在混合均衡（pooling equilibrium）之下，如果仲介業不管其為何種類型都傳遞相同的訊號，及得到相同的佣金，則這信號必定是不提供任何保證。 This paper applied signaling concept to analyze the economic meaning of existing-housing contract warranties. In order to decrease the problem of asymmetric information, brokerage firm can offer the method of warranties to inform the buyers the quality of product or service. The buyer may believe that brokerage firm cannot impossibly offer the warranties to the defects in product(outcomes of effort ), so he would believe certainly the quality of product(service) to be better. This is credible in a long run, so called signaling. Perhaps, the existing-housing contract warranties existed the function of the signaling to transmit information to consumers. The existing-housing contract warranties can't guarantee no problems to the transaction process, but it may inform to the consumers' that brokerage firm offering the warranties will possibly reduce the problems in the transaction process.' Applying the signaling theory, we can get lots of conclusions. In separating equilibrium, if brokerage firm is lower to the cost of warranties, then he will offer the warranties. If brokerage firm is higher to the cost of warranties, then he will not do. In pooling equilibrium, the brokerage firms , any types or costs of warranties, all transmit the same signal and attain the same commissions, then this signal must be no any warranties.