Introduction: Growing scholarly interest in the governance–risk nexus has yet to produce consensus on whether voluntary social disclosure meaningfully reduces firm-level risk, particularly in emerging markets where ownership structures differ markedly from Western contexts. This study examines whether corporate social disclosure reduces firm risk in Saudi Arabia and whether concentrated ownership moderates this relationship.

Methods: Using a balanced panel of 86 non-financial firms listed on the Tadawul over 2019–2024 (N = 516 firm-year observations), we constructed a 48-item Social Disclosure Index hand-collected from annual reports and aligned with GRI standards and Saudi CMA guidelines. Firm risk was captured through annualised stock return volatility, systematic risk (beta), and idiosyncratic volatility. Fixed-effects regressions with cluster-robust standard errors address within-firm heterogeneity, while Two-Step System GMM estimation accounts for potential endogeneity of disclosure decisions.

Results: Greater social disclosure is associated with significantly lower total and idiosyncratic risk, with weaker but directionally consistent effects on systematic risk. Ownership concentration attenuates this risk-reducing benefit: the interaction between disclosure and block-holding is positive and significant, and the disclosure effect becomes statistically indistinguishable from zero only at approximately 93% ownership concentration. Subsample analyses show that the disclosure–risk association is substantially stronger among firms with below-median ownership concentration.

Conclusions: The findings demonstrate that the risk-reduction benefits of corporate social disclosure are conditional on ownership structure. In highly concentrated environments, disclosure becomes less effective, providing evidence that transparency outcomes are fundamentally governance-contingent in emerging markets.