The article by Hyun-Jung Nam, Mehmet Huseyin Bilgin, and Doojin Ryu explores the strategic role of environmental, social, and governance (ESG) activities in enhancing firm value, particularly in family-owned firms. Using data from Korea, the authors investigate the interplay between ESG investment and family ownership. Their findings indicate that ESG activities can mitigate agency problems inherent in family ownership but require careful management to maximize firm value. The study introduces the concept of the marginal effect of ESG, decomposes its factors, and identifies a critical threshold of family ownership that is crucial for increasing firm value through ESG activities. Depending on a firm's position relative to this threshold, the authors recommend strategies for increasing or reducing ESG investment, emphasizing the timing of such investments as a key strategic consideration. The research provides practical insights for family-owned firms to make informed decisions about ESG investment, contributing to both their sustainability and the long-term vitality of ESG activities.The article by Hyun-Jung Nam, Mehmet Huseyin Bilgin, and Doojin Ryu explores the strategic role of environmental, social, and governance (ESG) activities in enhancing firm value, particularly in family-owned firms. Using data from Korea, the authors investigate the interplay between ESG investment and family ownership. Their findings indicate that ESG activities can mitigate agency problems inherent in family ownership but require careful management to maximize firm value. The study introduces the concept of the marginal effect of ESG, decomposes its factors, and identifies a critical threshold of family ownership that is crucial for increasing firm value through ESG activities. Depending on a firm's position relative to this threshold, the authors recommend strategies for increasing or reducing ESG investment, emphasizing the timing of such investments as a key strategic consideration. The research provides practical insights for family-owned firms to make informed decisions about ESG investment, contributing to both their sustainability and the long-term vitality of ESG activities.