Indexes of market concentration: ambiguous informational content

Abstract. The paper deals with the evidences of ambiguity of communication between market structure (distribution of market shares – competences of its subjects) and quantitative estimates of unevenness of these distributions at application of methods of competences concentration index assessment (market shares) of their subjects. The most known subjects are decile and quintile coefficients, Lorenz-Jeanie's method (Jeanie's index) and Herfindahl-Hirschman index: absolutely different distributions of competences can be character-ized by the same value of index.