The strategic role of environmental, social, and governance (ESG) activities in firm performance has recently drawn increasing attention. In particular, the dynamics of ESG management in family-owned firms have become a crucial factor in increasing firm value. Using novel data from Korea, a suitable context for our analysis, we focus on the interplay between ESG investment and family ownership. Our results reveal that ESG activities can mitigate the agency problems inherent in family ownership, but their careful management is essential for maximizing firm value. We introduce the concept of the marginal effect of ESG, decompose its factors, and identify a critical threshold of family ownership that is instrumental for increasing firm value through ESG activities. Depending on a firm’s position relative to this threshold, we recommend strategies to increase or reduce ESG investment, showing that the timing of such investment or disinvestment in ESG activities emerges as a key strategic consideration. Our findings provide practical insights for family-owned firms to make informed decisions on ESG investment, thereby contributing not only to their own sustainability but also the long-term vitality of ESG activities.

环境、社会和治理（ESG）活动在公司绩效中的战略作用最近引起了越来越多的关注。尤其是家族企业的ESG管理动态已成为提升企业价值的关键因素。我们使用来自韩国的新数据（适合我们的分析背景），重点关注 ESG 投资与家族所有权之间的相互作用。我们的结果表明，ESG 活动可以缓解家族所有权固有的代理问题，但其谨慎管理对于实现公司价值最大化至关重要。我们引入了 ESG 边际效应的概念，分解了其因素，并确定了家族所有权的关键阈值，该阈值有助于通过 ESG 活动增加公司价值。根据公司相对于该阈值的地位，我们建议增加或减少 ESG 投资的策略，表明对 ESG 活动进行此类投资或撤资的时机已成为关键的战略考虑因素。我们的研究结果为家族企业在 ESG 投资方面做出明智的决策提供了实用的见解，从而不仅有助于其自身的可持续发展，而且有助于 ESG 活动的长期活力。