Should instant and offline channels share the same price? Retailers' pricing strategies under platform coupon mechanisms

Purpose This paper examines how platform-issued coupons influence retailers' pricing strategies across instant and offline channels in a platform-based retail system. It aims to identify optimal pricing and coupon mechanisms that balance platform coordination efficiency, retailer profitability, and consumer welfare under varying delivery times and commission rates. Design/methodology/approach We develop a game-theoretic model involving a platform, a retailer, and consumers to characterize strategic interactions in an instant retail system. The model incorporates consumer delivery-time sensitivity, delivery lead time, and commission rates to derive equilibrium prices, coupon levels, and profit outcomes under both uniform and differentiated pricing strategies. We further compare firms' decisions and market outcomes under different coupon issuance mechanisms and channel structures. Findings The results show that differentiated pricing improves platform and retailer profits when delivery time is long or commissions are high by enabling flexible cross-channel demand reallocation. In contrast, uniform pricing benefits consumers in low-commission environments by narrowing inter-channel price gaps and mitigating excessive competition. Expanding coupon coverage from single- to dual- and multi-channel mechanisms enhances overall welfare and competitiveness but increases the platform's subsidy burden. Originality/value This study integrates coupon mechanisms with pricing strategies in instant retail and develops a unified analytical framework to examine how delivery time and commission rates shape cross-channel interactions. It provides actionable insights for platforms and retailers on designing efficient and sustainable multichannel coordination policies.