From Chordia et al. (2014), in the recent period of increased liquidity, the majority of US stock market returns anomalies have attenuated. However, as Thailand is a retail-based stock market, the stock market returns anomalies might not attenuate in the period of increased liquidity.
In this paper, I use data from SET and mai markets from 2005 to 2019 to conduct time series regression to test the hypothesis. My finding is, first, apart from momentum returns anomalies in the mai market, the size, value, and momentum returns anomalies still exist in Thai stock markets. Second, most of the returns anomaly (4 out of 6) in Thai stock markets are not statistically attenuate over time. Finally, the results from the time series regression suggest that the increase in liquidity does not attenuate the returns anomalies in the Thai stock markets. In addition, I run panel regressions (both fixed and random effects estimations) to check the robustness, and the results are similar to time series regression. The conclusion remains that the increase in liquidity does not attenuate the returns anomalies in the Thai stock markets.