Abstract: In e-commerce promotion activities, the platform usually uses price discount as a promotional tool, and merchants participating in the price promotion must sell goods in accordance with the price discount released by the platform. It is difficult for low price discount to attract consumers, and the insufficient number of consumers can not attract more merchants to participate in promotional activities. Although the higher price discount attracts more consumers, because the price discount released by the platform is often borne by the merchants, the excessive price discount will affect the profits of the merchants participating in the price promotion, and reduce the willingness of the merchants to participate in the price promotion. In price promotion activities, how to determine reasonable discount pricing to attract merchants and consumers to participate in price promotion activities is an important issue for platform operation. In platform price promotion, the pricing behavior of merchants directly affects the actual purchase price of consumers, thus affecting the demand for the goods and profits of both parties. In addition, the platform profits not only come from the transaction fees of merchants, but also from the advertising investment of merchants. Therefore, the consideration of merchant pricing and advertising investment in the price discount decision of the platform has an important effect on the promotion activities.
   Based on the game theory and optimization theory, this paper studies the e-commerce market of one e-commerce platform, one merchant and many consumers from the perspective of platform discount pricing decision of price promotion activities, and builds the price promotion game model of platform and merchant. Through comparative analysis, the paper studies platform discount pricing, commodity pricing and advertising investment strategies during price promotion activities.
   We find that when the platform offers more incentives, the actual transaction price of the goods is lower, and merchants get less income. At this time, the merchants’ advertising investment is correspondingly lower. When the preferential power of the platform is reduced, the transaction price of the goods will increase, and merchants will increase the advertising investment. When the platform offers less, merchants will attract consumers by reducing prices, and the level of advertising investment will remain unchanged. Moreover, the optimal price discount coefficient of the platform is not that the lower the better, on the contrary, the optimal price discount coefficient of the platform is to maintain a high level. Although the price discount coefficient of the platform is low, it can obtain more transaction share, but the reduction of advertising investment of merchants makes the platform’s income low. When the price discount coefficient of the platform is high, merchants will find that the optimal actual transaction price on the demand curve of the commodity is lower than the price after the price discount, and merchants will achieve the optimal actual transaction price by reducing the price. In this case, the actual transaction price of merchants is high and the transaction volume is reduced, but the advertising investment of merchants increases, resulting in the final revenue of the platform.
   From the perspective of platform discount pricing of price promotion activities, this paper considers the impact of merchants’ pricing and advertising investment decisions on platform revenue, and provides theoretical support for improving the transaction efficiency of e-commerce market.

Key words: two-sided market, e-platform, advertising investment, price discount

摘要： 本文考虑了商家定价和广告投资决策行为,构建了电商平台价格折扣决策模型,研究了价格促销活动中平台最优价格折扣决策和商家定价和广告投资决策。研究表明,商品消费者效用越高平台最优价格折扣系数越大,商品单位成本越高平台最优价格折扣系数越大。平台促销收益随消费者数量、商品的消费者效用增加而增加;随平台交易费率和广告费用系数增加呈先增加后保持不变的趋势。价格折扣系数较低时,商家保持正常销售时期的价格不变,广告投资水平随价格折扣系数降低而降低;价格折扣系数较高时,商家最优定价随价格折扣系数降低而提高,广告投资水平不变。

关键词: 双边市场, 电商平台, 广告投资, 价格折扣