Supakkoon Chairit

Type of the article: Research Article

Abstract
Thai retail stock investors face competing pressures from sustainability criteria, behavioral bias, and volatility typical of an emerging market. The study examines relationships among sustainable investment, heuristic bias, and financial literacy in predicting investment decisions, and tests risk perception as a mediator and investment horizon as a moderator. A primary survey was administered from August 1 to August 31, 2025, using self-administered questionnaires. Data from 580 retail investors across six Thai regions were analyzed in SmartPLS 4.0 using 5,000 bootstrap resamples. The results indicate that heuristic bias (β = 0.428, p < 0.001) and financial literacy (β = 0.401, p < 0.001) emerged as the strongest predictors of risk perception, and sustainable investment also had a positive effect with a smaller magnitude (β = 0.145, p < 0.001). Risk perception had a positive effect on investment decisions (β = 0.439, p < 0.001) and mediated all three predictors, with the largest indirect effect observed for heuristic bias (indirect β = 0.188, p < 0.001). Investment horizon strengthened the association between sustainable investment and investment decision (β = 0.417, p < 0.001). The results confirm policy attention to financial education and bias-awareness initiatives and support efforts to encourage longer holding periods among retail investors. Market stakeholders can also improve the quality of environmental, social, and governance disclosures and promote practical risk-assessment frameworks to enable retail investors to translate sustainability information into more informed investment decisions.