Closely Competing Firms and Price Adjustment: Some Findings from an Online Marketplace*
利用日本比价网站上零售商每秒更新的价格数据，研究发现当产品均价快速下降时，价格调整频率和幅度都会增加；价格调整频率存在正自相关，而幅度则没有，表明零售商定价更符合状态依赖而非时间依赖。
Abstract We investigate retailers' price‐setting behavior using a unique dataset containing by‐the‐second records of prices offered by closely competing retailers on a major Japanese price‐comparison website. First, we find that, when the average price of a product across retailers falls rapidly, the frequency of price adjustments increases, and the size of price adjustments becomes larger. Second, we find positive autocorrelation in the frequency of price adjustments, implying that there tends to be clustering where price adjustments occur in succession. In contrast, there is no such autocorrelation in the size of price adjustments. These two findings indicate that the behavior of competing retailers is characterized by state‐dependent pricing rather than time‐dependent pricing.