We study the practice of influencer marketing in oligopoly markets and its effect on market efficiency. In our model, each consumer is influenced by choices of a subset of other consumers. Firms gather information on consumers’ influence and price discriminate using this information. In equilibrium, firms charge premia/subsidize below-/ above-average-influential consumers; the premia/discounts depend on the strength of network effects and on how much information firms have on consumers’ influence. Influencer marketing leads to inefficient consumer-product matches. Firms’ investments in information are strategic complements, leading to a race for information acquisition that erodes welfare and firms’ profits but increases consumer surplus. (JEL D11, D21, D43, D83, D85, L13, M31)