Cross-listed companies leverage dual or multiple listings to access diversified capital markets, expand their investor base, and optimize risk allocation. Despite sharing identical ownership rights, A-shares and H-shares of the same firm persistently exhibit significant price disparities, a phenomenon termed “H-share discounts”. Prior studies attribute this anomaly to cross-market regulatory divergence, information asymmetry, heterogeneous investor structures, and liquidity gaps. This paper pioneers an investigation into whether sustainable information assurance—a mechanism to enhance disclosure credibility—can mitigate the information asymmetry between A-share and H-share investors.

Focusing on A+H dual-listed firms from 2017 to 2022, this paper employs a two-way fixed effects model to empirically test the hypothesis that sustainable information assurance reduces H-share discounts. The results demonstrate that the assurance significantly narrows the price gap, with the effect magnified under three conditions: Assurance providers are accounting firms with professional auditing expertise; assurance scope is verified explicitly; and a higher proportion of environmental or industry-specific material indicators are assured. Heterogeneity analysis further reveals a stronger effect in firms characterized by higher ESG rating divergence, more green innovation, higher green expenses, and lower internal and external governance levels.

Theoretically, this paper extends the literature on the economic consequences of sustainable information assurance by identifying its role in harmonizing cross-market pricing efficiency through information asymmetry reduction. Practically, it provides actionable insights for regulators to make sustainable information assurance standards or policies, urges listed firms to adopt high-quality assurance practices, and informs global investors about assurance’s signaling value in assessing cross-listed equity risks and returns.