Abstract: Compared with offline shopping, the uncertainty of product about quality and attribute, and the lack of the sense of use are the disadvantages of online shopping, which makes more and more online retailers provide money-back guarantee (MBG) to raise consumers’ purchasing confidence. Simultaneously, in order to cope with increasingly fierce market competition, online retailers often adopt “value increasing” promotion to stimulate sales. In fact, well-experienced speculative consumers will choose to purchase an additional add-on item to enjoy price discounts when their purchase amount is below the full reduction threshold. After successful payment, they may return the additional add-on item, which causes huge resources allocation pressure and return losses for online retailers. On the other hand, in order to improve the promotion effect, retailers may implement different product diversification strategies (such as selling complementary products) to enhance customer experience and meet the needs of different consumers. Existing research shows that due to complementary characteristics of complementary products, consumers can achieve greater benefits by using complementary products simultaneously. Therefore, how should retailers who sell incompletely complementary products, price when faced with the speculative consumers’ add-on items return behavior? Could the elasticity of complementarity between products alleviate the impact brought by speculative consumers? And how does MBG affect consumer the purchasing behavior and retailer’s profits?
Existing research on promotional returns primarily focuses on the impact of consumer’s strategic waiting behavior on firm’s decision-making, with little attention given to consumers’ speculative behavior. And this behavior is a new phenomenon caused by retailers adopting “value increasing” promotion and allowing MBG together. In addition, in the study of incompletely complementary products, most of the literature usually analyzes its impact on the optimal bundling sales strategy of enterprises based on deterministic complementarity elasticity, ignoring the measure of complementarity and its analysis of the phenomenon of add-on items return in the online bundled sales model.
Based on this, we attempt to analyze the problem of “value increasing” promotion pricing for retailers selling imperfect complementary products, considering a shopping scenario consisting of one retailer and two types of consumers (speculative consumer and ordinary consumers, respectively). Among them, speculative consumers are informed consumers who can enjoy price promotion by pretending to purchase an additional add-on item and return it after successful payment. Ordinary consumers are those who are uninformed and will notpretend to make an additional add-on item purchase to get price discounts and then ask for a refund. They make purchase decisions based on the degree of complementarity between two products. To address the above problem, we first provide a method for retailers to measure the degree of complementarity between products. Then, we construct a game model considering the speculative consumers’ add-on items return behavior, and explore the impact of promotional pricing strategies that differentiate the degree of complementarity between products and MBG on retailer equilibrium decisions. Finally, by comparing the existence and absence of complementary elasticity between incomplete complementary products under the provision of MBG, the mechanism of the impact of complementary degree on the speculative consumers’ add-on items return behavior is analyzed.
Our results show that: (1)The promotion price in the case of complementary elasticity between two products decreases with an increase in complementary degree, and it may be lower than the promotion price in the case of no complementary elasticity. (2)MBG will affect consumers’ product purchase willingness, which is more favorable for product demand with complementary elasticity, and MBG will also drive-up promotional prices. (3)However, from the perspective of maximizing profits, online retailers may provide MBG only when the proportion of speculative consumers is small enough. (4)Finally, by comparing the profits of imperfect complementary products with and without complementary elasticity in the mode with MBG, we find that the complementary elasticity of imperfect complementary products can alleviate partly the negative impact of speculation consumer add-on items return behavior.

Key words: speculative consumers, “value increasing” promotion, add-on items return behavior, complementarity elasticity, imperfect complementary products

摘要： 基于销售不完全互补产品的零售商存在的满减促销定价问题,考虑到市场中存在投机型消费者的凑单退货行为,建立单周期销售决策模型,分析产品之间互补程度差异化的促销定价策略以及退款保证对零售商均衡决策的影响。研究表明:产品之间具有互补弹性情形下促销价格随着互补程度的增大而减小,且其并不总是高于无互补弹性情形下的促销价格。退款保证会推升产品的促销价格,同时该模式下最优促销价格受到消费者凑单退货行为的影响。从利润最大化的角度,网络零售商只有在投机型消费者比例足够小时,才可能提供退款保证。最后,通过比较提供退款保证下不完全互补产品之间有无互补弹性对零售商利润的影响,发现产品之间的互补弹性能减弱由投机型消费者凑单退货行为造成的消极作用。

关键词: 投机型消费者, 满减促销, 凑单退货行为, 互补弹性, 不完全互补产品