Hi i need to calcualte whats called a herfindahl index. It is calculated by squaring the market share of each firm competing in a market and then summing the. The evolution of the sectoral concentration in portugal. The herfindahl index also known as herfindahlhirschman index, hhi, or sometimes hhiscore is a measure of the size of firms in relation to the industry and an indicator of the amount of competition among them. The herfindahl hirschman index hhi is a commonly accepted measure of market concentration. Professor hildebrandt works through an example showing how to calculate the herfindahlhirschman index and explaining what the hhi tells us about a markets competitiveness. This video shows how to calculate the hhi using several examples. This meaures how concentrated the ownership of a company is. The hhi belongs to a family of indices that also includes the rosenbluth index and the entropy index jacquemin. The term hhi means the herfindahlhirschman index, a commonly accepted measure of market concentration.
The herfindahlhirschman index hhi is a commonly accepted measure of market concentration. A mathematical analysis of the hirfindahlhirschman index. Pdf hirschmanherfindahl index determination under incomplete. For example, suppose i have a firm with 10 shareholders, each holding the following percentage the total usually adds up to less than 100% as some are missing. The hhi is calculated by squaring the market share of each firm competing in the market and then summing the resulting numbers. Assim chamado a partir do nome dos economistas orris c. Title calculate and visualize the herfindahlhirschman index. A evolucao da concentracao sectorial em portugal entre 1995 e 2006. Pdf a evolucao da concentracao sectorial em portugal entre 1995.
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