Boosting Firm Value: Sustainability Report and Good Corporate Governance Moderated by Firm Size

Abstract

Background: Firm value has become a central concern in capital market studies, as it reflects investor confidence and long-term corporate sustainability. Prior empirical evidence on the effects of sustainability reporting (SR) and good corporate governance (GCG) on firm value remains inconclusive, warranting further investigation, particularly with respect to potential moderating factors such as firm size proxied by market capitalization. Objective: This study aims to integrate sustainability reporting and good corporate governance variables that influence firm value by using firm size as a moderating variable. Methods: This research employed a quantitative methodology utilizing a purposive sampling strategy. The participants in the study comprised 62 manufacturing firms listed on the Indonesia Stock Exchange from 2021 to 2024. A cumulative total of 248 data observations were examined using SPSS software. Results: The findings of the study reveal that sustainability reporting (β = 2.981, p < 0.01), the presence of an independent board of commissioners (β = 4.275, p < 0.01), and the audit committee (β = 1.004, p < 0.01) each have a significant positive direct impact on firm value. Additionally, firm size plays a significant moderating role in the relationship between sustainability reporting and firm value (interaction β = 0.389, p < 0.05) as well as between the independent board of commissioners and firm value (interaction β = 0.421, p < 0.05). However, firm size does not moderate the relationship between audit committees and firm value (interaction β = −0.051, p > 0.05). These conclusions are drawn from a sample of 62 manufacturing firms listed on the Indonesia Stock Exchange (IDX) from 2021 to 2024, resulting in 248 company-year observations. Conclusion: Future research could explore other moderating variables such as profitability or apply the model in a cross-industry or cross-country context to test the robustness of these findings.