P2P借贷行业网络外部性测度研究

针对P2P借贷行业，应用归属曲线证明了其网络外部性的存在性，进而从供需理论入手构建了P2P借贷行业的网络外部性测度模型.收集中国50家P2P借贷平台2015年6月至2016年5月的月度运营数据，应用面板OLS，DOLS对其网络外部性进行测度.研究结果表明:在中国P2P借贷行业中，借款人数量和贷款人数量间存在着长期稳定的均衡关系；P2P借贷行业存在着正向的贷方网络外部性，外部性强度约为0.1，并未体现出明显的借方网络外部性.进一步通过Granger因果检验发现P2P借贷行业中存在由贷款人数量增长带动借款人数量增长的单向因果关系，因此，从外部性角度，P2P平台实施对贷款人补贴的策略是理性的. 

Measuring Network Externality in P2P Lending Industry

The attachment curve was used to examine the existence of network externality in P2P lending industry and a model based on supply and demand theory was proposed to measure it. Operational data of 50 domestic P2P lending platforms from June 2015 to May 2016 were collected. With these data, ordinary least square (OLS) regression and dynamic ordinary least square (DOLS) regression were used to measure their network externality. The results show that, there exists a long-term and stable relationship between the number of lenders and that of borrowers; P2P lending industry exhibits positive network externality around 0.1 at the lending side and does not show obvious network externality at the borrowing side. Further Granger Causality Test finds that the growth in the number of lenders is useful in forecasting the growth in the number of borrowers. Therefore, from the perspective of network externality, giving allowance to lenders is a reasonable strategy for P2P lending platforms.