A Tale of Two Networks: Common Ownership and Product Market Rivalry
研究了1995至2021年美国共同所有权上升的福利影响，构建包含所有权重叠和产品市场竞争两个网络的寡头博弈模型，发现共同所有权导致福利损失，消费者剩余向生产者转移。
Abstract We study the welfare implications of the rise of common ownership in the U.S. from 1995 to 2021. We build a general equilibrium model with a hedonic demand system in which firms compete in a network game of oligopoly. Firms are connected through two large networks: the first reflects ownership overlap, the second product market rivalry. In our model, common ownership of competing firms induces unilateral incentives to soften competition and the magnitude of the common ownership effect depends on how much the two networks overlap. We estimate our model for the universe of U.S. public corporations using a combination of firm financials, investor holdings, and text-based product similarity data. We perform counterfactual calculations to evaluate how the efficiency and the distributional impact of common ownership have evolved over time. Under the assumption that firms maximise a share-weighted average of their shareholders’ income, we find that the welfare cost of common ownership, measured as the ratio of deadweight loss to total surplus, has increased about ninefold between 1995 and 2021. Under alternative assumptions about corporate governance, the deadweight loss of common ownership ranges between 3.5 and 13.2% of total surplus in 2021. The rise of common ownership has also led to a significant reallocation of surplus from consumers to producers.