銀行與第三方支付：貨幣搜尋模型之應用

隨著電子商務與智慧型手機應用的發展，源自於擔保交易的第三方支付發展迅猛，成熟的第三方支付逐漸把服務拓展到借貸體系，形成一個龐大的信用中介系統。為此，本文通過建立一個貨幣搜尋模型，在存在銀行中介，貨幣與信用並存的市場上引入這種新型中介系統，討論了引入無抵押借貸體系非現金支付的第三方支付系統與有抵押借貸體系現金支付的銀行系統，探求由第三方支付系統所提供的這種新型信用支付如何影響交易與社會福利，不同金融中介之間的信息共享是否也能夠改善交易，以及貨幣政策對於這兩個系統的影響。我們的分析結果顯示：引入第三方支付系統能增加交易量，提高總體經濟福利；由於用作抵押品貸款的實質資產因成為抵押品的機率降低，資產價格略有下降。此外，輕微的通貨膨脹率促使有較高經濟福利的借貸限制均衡得以存在，當進入第三方支付系統機率提高到一定程度時，通貨膨脹率的提高將會增加交易量與經濟福利；任何一個系統的買家議價能力的提高，都會通過提高貨幣實質價值推動兩個市場的借貸與交易，增進整個經濟福利。

關鍵字

銀行；第三方支付；貨幣；借貸；資產價格；貨幣搜尋模型

並列摘要

With the development of e-commerce and smart mobile phone applications, third-party payment originating from secured transactions has developed rapidly, and mature third-party payment has gradually expanded the service to the credit fields, forming a huge intermediary system.Hence, by establishing a monetary search model, this paper introduces this new type of intermediary system. It discusses the third-party payment system with non-cash payment in exclusion mechanism and the bank system with cash payment in collateral mechanism, and explores how this new means of credit payment provided by the third-party payment system affects transactions and social welfare,whether information sharing among different financial intermediaries can improve transactions, and the impact of monetary policy on the two systems. Our analysis results show that the introduction of third-party payment system can increase transaction and welfare, while the real asset prices have a slight decline due to the lower probability of becoming collateral. In addition, the existence of money equilibrium with credit which has higher economic welfare requires some inflation, and the increase of inflation rate will raise transaction and welfare when the probabilily of entering the third-party payment system up to some degree; the improvement of the bargaining power of buyers in any system will promote trading and welfare of the two markets by raising the real value of money .