MARIAN SIMINICA, SILVIU VALENTIN CARSTINA, DANIEL CIRCIUMARU, LAVINIA NETOIU THE IMPACT OF THE MARKET CONCENTRATION RATIO ON THE PRODUCTIVITY ROMANIAN CHEMICAL INDUSTRY In this article we enlarge upon the market concentration ratio of all the companies in the chemical industry (divided into 16 areas of activity, according to the NACE code: The National Classification of Economic Activities), but also of the most important 50 companies in this sector, depending on the turnover. Throughout the paper, we deal with the correlation between the market concentration and profitability, determined by taking into consideration the net profit, ROA, ROE and the profit margin. The research results point to the existence of a weak correlation between the concentration ratio as an independent variable, and ROA and the profit margin as dependent variables. However, the correlation is direct and strong if connected to the net profit and ROE. For these two variables, there are patters of linear regression that have been brought together.