고객에서 공급자로의 ESG 파급효과: 교섭력의 조절효과

This study examines how environmental, social, and governance (ESG) practices of major customer firms diffuse to their upstream suppliers and identifies the conditions under which this spillover strengthens or weakens. While prior work has documented positive ESG transmission within supply chains, limited attention has been paid to supplier-side bargaining power as a determining mechanism. Using a panel dataset of 2,567 customer-supplier dyads among North American firms from 2003 to 2019, we combine the Compustat Customer Segment file with MSCI KLD ESG ratings and compute a net ESG score based on seven strength and concern dimensions. To ensure temporal direction, all independent variables are lagged by one year. The empirical results confirm a positive and significant spillover: higher ESG performance of major customers leads to improved ESG outcomes for suppliers. Moreover, this effect becomes stronger when customer dependence is high, as reflected by concentrated revenue ties. In contrast, the spillover weakens when suppliers possess greater bargaining power, operationalized as higher market share or financial liquidity. These findings reveal that ESG diffusion is conditional rather than automatic, shaped by asymmetric power structures in supply chain relationships. This study contributes by clarifying when customer-driven sustainability governance becomes effective and offers implications for policymakers and firms designing supplier monitoring, disclosure standards, and incentive mechanisms to promote ESG adoption across supply networks.