ESG Performance, Firm Value, and Market Risk in Maritime and Fishery Firms: Panel Evidence from Korea

Environmental, social, and governance (ESG) ratings aggregate heterogeneous corporate activities whose valuation and risk associations may vary by industry and dimension. This study examines a balanced panel of 556 non-financial KOSPI-listed firms in Korea from 2012 to 2025 (7784 firm-year observations), partitioned into 24 maritime and fishery firms (336 observations) and 532 non-focal comparison firms (7448 observations). Firm value is measured by Tobin’s Q and market risk by the annual standard deviation of daily stock returns. Separate firm and year fixed-effects regressions describe within-group associations, while pooled sector-by-ESG interaction models formally test slope differences. In the focal sample, the overall ESG, social, and governance scores are negatively associated with firm value, whereas in the joint risk model, the environmental pillar is positively associated with volatility and the social pillar is negatively associated. Formal interaction tests indicate a significant sector difference for the environmental-value association and for the environmental and social risk associations; joint tests reject the null that the E-S-G sector-interaction terms are jointly zero for both outcomes (p = 0.037 for value and p < 0.001 for risk). The sector differences are more stable for market risk than for firm value: environmental and social risk interactions remain statistically detectable under richer and more flexible pooled specifications, whereas the joint value interaction weakens when nuisance slopes are allowed to vary by sector. Leave-one-firm-out and leave-one-subsector-out diagnostics preserve the main environmentally positive and socially negative risk signs, although statistical strength varies with subsector composition. Wild Cluster Bootstrap checks further support the environmental and social risk patterns, while lagged and post-2022 analyses narrow the temporal and valuation claims. Detailed-component results are treated as hypothesis-generating and evaluated using false-discovery-rate adjustment. The results support a differentiated, sector-sensitive interpretation of ESG ratings but remain associational rather than causal.