Attention Oligopoly

We model digital platforms as attention brokers that have proprietary information about their users’ product preferences and sell targeted ad space to retail industries. Retail producers—incumbents or entrants—compete for access this bottleneck. discuss when increased concentration among results in a tightening of the bottleneck, leading higher prices, fewer ads being sold entrants, lower consumer welfare The effect is characterized terms patterns individual usage across platforms. A merger assessment relies on aggregate platform alone can be highly biased. (JEL D43, D83, G34, L81, L86, M37)