Multi-Seller Access Pricing for Shopping Platforms

Through charging or subsidizing shoppers, a platform participates in the pricing game played by n hosted third-party sellers, who sell different products and share profits or revenues with the platform. The platform's equilibrium access price for shoppers is determined by bilateral effects between the platform and each seller. A "sharing effect" is represented by the profit or revenue share taken from a seller. A "buzz effect" embodies a seller's ability to attract shopper traffic to the platform through adjusting her own price, as measured by the platform's cross-price elasticity with respect to the seller's price. These effects are aggregated across all sellers, and deducted from the platform's standard markup. A positive access fee is optimal if the sum of profit shares taken from sellers does not exceed 1, or if the revenue-share sum does not exceed the per-shopper cost. When either sum exceeds a higher threshold, an access subsidy emerges