Beyond the need to boast: Cost concealment incentives and exit in Cournot oligopoly

► A dominant firm's disclosure strategy may differ from that of accommodating firms. ► A dominant Cournot oligopolist may conceal its cost if this can exclude competitors. ► Information sharing may make consumers better off on average if it avoids exclusion. ► Introducing a dominant firm can reverse effects of information sharing on consumers. ► Also strategic disclosure choices may yield information concealment to induce exit.