PurposeThis study examines the association between internal corporate governance mechanisms (i.e. board of directors and audit committee) and the information value of bank earnings. The authors comparatively assess this association across different bank types, Islamic versus conventional banks. The authors also investigate the mediating effect of Shariah governance.Design/methodology/approachThe authors utilize a unique and an international sample of 723 bank-year observations representing 100 listed banks from 16 countries during the period 2007–2015. The authors investigate the characteristics of the board of directors and audit committee (i.e. size and independence) and employ three core analyses for earnings informativeness (i.e. earnings persistence, cash flow predictability and reliability of loan loss provisions). Additional analyses address Shariah supervisory boards’ (SSBs’) size, financial expertise and multiple outside directorships. The authors use the random-effect Generalised Least Squares (GLS) estimation technique and provide several robustness checks and sensitivities.FindingsThe authors find that, on average, having large and independent boards (and audit committees) increases the informativeness of reported earnings for banks. Conditional on bank type, our results report strong evidence for differential effects across the two alternative banking systems. In Islamic banks, large and independent board of directors (and audit committees) is positively associated with all measures of information value. There is insignificant evidence for conventional banks. However, SSBs show no significant effect on the reported earnings’ informativeness.Originality/valueThis is the first study, to the best of our knowledge, that empirically and comparatively assesses the information value of reported earnings in association with effective internal governance while recognizing the institutional characteristics of different bank types. The authors offer new insights to policymakers, investors and other stakeholders located within countries operating on a dual banking system. The results could help regulators to improve their rules/guidance related to double-layer governance and financial reporting quality.