禮券發行對消費者福利以及雙占零售商定價與折扣行為之影響

Abstract

本研究主要在探討零售商發行禮券對於消費者福利與零售商的商品定價策略以及折扣行為的影響。我們建立一個單期的賽局模型，假設雙占零售商各自擁有不同數量的忠誠顧客以及面對一群視兩家零售商完全同質的游移顧客。在僅有一家零售商單獨發行禮券而且游移顧客不會購買禮券這個條件下，研究發現禮券對商品市場的影響取決於發行者與銷售量的多寡。當忠誠顧客較少的零售商發行禮券為非熱銷狀況，將可能降低零售商之間的折扣競爭，除了屬於發行者的忠誠顧客福利不變，其餘購買商品的消費者福利下降；當忠誠顧客較多的零售商發行禮券為非熱銷狀況，將可能提高零售商之間的折扣競爭，所有購買商品的消費者福利上升。當忠誠顧客較多的零售商發行禮券為熱銷狀況，將可能提高零售商之間的競爭，所有購買商品的消費者福利上升，但是在熱銷超過一個門檻，屬於非發行者的忠誠顧客福利反而可能比禮券發行之前還要低。當市場上出現禮券非熱銷狀況，發行者必定為忠誠顧客較少的零售商。零售商的禮券銷量門檻絕不會隨游移顧客增加而上升；忠誠顧客較少的零售商之禮券銷量門檻絕不會隨自己忠誠顧客增加而下降；絕不會隨對手之忠誠顧客增加而改變；忠誠顧客較多的零售商之禮券銷量門檻隨自己的忠誠顧客增加而上升；絕不會隨對手之忠誠顧客增加而上升。

We analyze the impact of giftcard issuance on consumer welfare and retailers’ price dealing behavior by building a one-period game-theoretic model in which duopolistic retailers with different loyal bases are also faced with a group of switchers who regard the two retailers’ products as perfect substitutes. We focus on the case where exactly one retailer may issue a giftcard and only its loyal customers may want to purchase it. Our results show that the impact of giftcard issuance depends on the identity of the issuing retailer and the sales volume of giftcards. We obtain the following results. First, if the giftcard-issuing retailer has a smaller loyal base than its rival and if the giftcard issuance generates a low sales volume, then giftcard issuance helps mitigate competition between that retailers, and in that case all consumers that do not purchase the giftcard are worse off, except the loyals of the issuing retailer, whose welfare remains the same. Second, if the giftcard-issuing retailer has a larger loyal base than its rival and if the giftcard issuance generates a low sales volume, then giftcard issuance may intensify competition between that retailers, and in that case all consumers that do not purchase the giftcard are better off. Third, if the giftcard-issuing retailer has a larger loyal base than its rival and if the giftcard issuance generates a high sales volume, then again giftcard issuance may intensify competition between that retailers, and in this case all consumers that do not purchase the giftcard are better off, except the loyals of the non-issuing retailer, whose welfare may become lower. Fourth, a low giftcard sales volume indicates that the issuing retailer must have a smaller loyal base than the non-issuing retailer. Fifth, a retailer is willing to issue a giftcard only when it expects the giftcard sales volume to exceed a lower bound. The larger the size of the switchers the larger that lower bound is required to be. Sixth, the required lower bound for the giftcard sales volume is weakly increasing in the size of the issuing retailer’s loyal base. Finally the required lower bound for the giftcard sales volume is independent of the size of the non-issuing retailer’s loyal base in the case where the issuing retailer has a smaller loyal base than the non-issuing retailer, but in the opposite case, the required lower bound for the giftcard sales volume is weakly decreasing in the size of the non-issuing retailer’s loyal base.