PurposeRecent research finds that the effect of corporate social responsibility (CSR) information, especially when CSR is not related to core business activities (immaterial CSR issues), on investment decisions will be eliminated when it is explicitly assessed. As CSR expectations from investors appear to be different across specific cultures and countries (Van der Laan Smith et al., 2010), we aim to investigate (1) the effect of CSR materiality on investors' willingness to invest and (2) how the explicit assessment of CSR information moderates the effect of explicit assessment and CSR materiality on investment judgment by professional investors in Thailand.Design/methodology/approachA 2 × 2 between-subject experiment was conducted based on 136 professional investors.FindingsOverall, the results suggest that an investor's willingness to invest is greater when CSR is material than when CSR is immaterial. In addition, the assessment of willingness to invest in a firm's stock is not affected by the presence or absence of explicit assessment of the material CSR. However, the results suggest that when CSR issues are immaterial, explicit assessment significantly removes the effect of CSR performance on the investor's investment judgment. Consistent with the findings from Guiral et al. (2019), professional investors seem to process CSR information in a similar way as nonprofessional investors.Practical implicationsThe findings suggest that material CSR information has a significant impact on the investment decisions of professional investors. This is consistent with the materiality guidance provided by the Sustainability Accounting Standard Board (SASB) as helpful in improving the value of CSR information for investors. These results should be of interest to both business people and regulators because, despite differences in the cultural and audit environment, the results confirm that professional investors in Thailand use CSR information in an experimental setting, thereby providing some evidence of value creation from CSR activities and nonfinancial disclosures.Originality/valueWhile recent experimental research has primarily examined how nonprofessional investors evaluate CSR information in Western countries, this study extends the literature by focusing on professional investors in emerging capital markets and how they use CSR information in their investment decisions (Coram et al., 2009). The study also addresses the call for research on differences in CSR reporting and practices in different cultures and countries (Van der Laan Smith et al., 2010; Coram et al., 2009) to provide insights into how professional investors in Thailand use CSR information to formulate investment judgments.