The concept of market concentration is expressed as the number of distrubutions of buyers and sellers in the product market. There is a negative relationship between market concentration and the number of companies. As the degree of concentration increases, competition level decreases. There are many methods used to measure the level of concentration in the market. In this paper, the competition level in the internet search engines is invistaged for Turkey during 2009-2015 using an analysis of various concentration methods. The results from this study, “N firm concentration ratio index is over %90. This shows that, markets have very high level concentration and competition very low. Herfindahl – Hirschman concentration index between 4000 and 10000 value for receiving, markets very high concentration and monopoly market. Entropy Indeks, Hall Tideman Indeks, Comprehensive Concentration Indeks have same result with Herfindahl – Hirschman concentration index and N firm concentration ratio.

Market concentration, search engines, concentration ratio index.