Influence of equity structure in China’s high-tech manufacturing industry on enterprise value under epidemic shocks

The COVID-19 pandemic represented a profound exogenous shock to global economic systems, posing substantial challenges to corporate governance frameworks and value creation—particularly within technology-intensive industries. This study investigates the relationship between equity concentration and corporate value in China’s high-tech manufacturing sector from 2019 to 2023, with particular attention to the mediating role of R&D investment. Drawing on a balanced panel dataset comprising 642 listed firms, we employ fixed-effects regression models complemented by instrumental variable (IV) estimation to rigorously address endogeneity concerns. Empirical results indicate that, after accounting for endogeneity, equity concentration exerts a significantly larger negative effect on firm value (IV estimate: β= −13.105, p < 0.01) than conventional OLS estimates suggest—indicating that standard OLS estimates are subject to pronounced downward bias. Although traditional mediation analysis points to a partial mediating role for R&D investment—explaining 18–23% of the total effect—instrumental variable–based mediation tests yield statistically insignificant indirect effects, underscoring the sensitivity of this channel to endogeneity correction. Notably, the detrimental impact of equity concentration on firm value was markedly attenuated during the pandemic period. Moreover, substantial industry-level heterogeneity emerges: the negative association is most pronounced in capital-intensive subsectors, including aerospace and electronic equipment manufacturing. These findings enrich theoretical understanding of how corporate governance mechanisms interface with innovation dynamics under extreme external shocks. They also yield nuanced practical implications: policymakers and corporate leaders should explicitly account for industry-specific attributes and macroeconomic contexts when designing and optimizing ownership structures—since the effectiveness of governance mechanisms is highly contingent upon prevailing environmental conditions.