摘要：Thanks to the study of 124 firms listed on the SBF 250 index, the researchers were able to identify the determinants of information asymmetry between firms' managers and investors, using panel data over the period ranging from 1999 to 2008. The results of the random effects model show that most variables are not significant. There is a problem of heteroscedasticity and a problem of autocorrelation. In this regard, the researchers have used the method of generalized least squares to overcome these problems. The results obtained, by using this method, show that the trading volume, as well as the volatility of stock returns, has a positive and significant effect on information asymmetry. The coefficient of the insiders' trading variable is high what shows the relevance of this variable in the explanation of the information asymmetry problem. However, the stock price variable has a negative effect. These results are conclusive to corroborate the thesis of variables relevance resulting from the theory of markets microstructure
