Impact of In-Session Price Increases in the Cart on Consumer Behavior: Evidence from an Online Marketplace
(A2026-133795)

AUTHORS

Domenico Fabrizi, Catolica-Lisbon; Serkan Mehder, University of Colorado Boulder; OVUNC YILMAZ, University of Colorado Boulder/Assistant Professor; Jiankun Sun, Imperial College London; Zifeng Zhao, Notre Dame

ABSTRACT

Price increases during shopping sessions are increasingly common in online platforms, yet little is known about their profitability and their effects on customer behavior. We study a leading European online pharmaceutical marketplace where fulfillment constraints require that each order be sourced from a single pharmacy, which can trigger in-session price increases once users have started building their carts. We exploit a large-scale randomized field experiment that assigns new users to a Price Increase Group—who always see updated cart prices— or to a No Price Increase Group—where the platform absorbs price increases and keeps prices fixed. We show how users react to price increases in terms of conversion rate, checkout value, and retention. Our results reveal when the platform can display price increases without severely harming sales and when absorbing them is likely to be more profitable in the long run.