The examination of accounting anomalies of Fama & French three factor model at the firm level by hierarchical Bayesian and standard Markov chain Monte Carlo simulation

Anomaly is deviation from common rules. In finance; it can be defined as a pattern in the average of stock returns that is not consistent with the prevailing asset pricing models literature. For anomaly investigation, two common methods are used: portfolio approach and individual firm approach. The aim of this study is to examine accounting anomalies of Fama and French three-factor model at the individual firm level due to the weaknesses of the portfolio approach. The sample consists of 1150 firm – year (13800 firm-month) observations in Tehran Stock Exchange in the period of 2008-2017. Bayesian approach and standard Markov chain Monte Carlo simulation have been used to test hypotheses. The results of the research show that size, book value to market value, profitability, asset growth, working capital accrual items, investments, net stock issuance and external financing, cannot be interpreted as anomaly for Fama and French three factors model when the test is at the individual firm level.