Should platforms be allowed to charge ad valorem fees?
研究平台收取与交易价格挂钩的从价费用的福利影响，发现禁止此类费用通常会降低福利，基于亚马逊市场和Visa借记卡数据的校准模型也支持这一结论。
Many platforms that facilitate transactions between buyers and sellers charge ad valorem fees in which fees depend on the transaction price set by sellers. Given these platforms do not incur significant costs that vary with transaction prices, their use of ad valorem fees has been questioned. In this paper, using a model that connects ad valorem fees to third‐degree price discrimination, we evaluate the welfare consequences of banning such fees. We find the use of ad valorem fees generally increases welfare, including for calibrated versions of the model based on data from Amazon's marketplace and Visa's signature debit cards.