posted by sam .
How do you calculate market share?
please will somebody help me
You need sales data from different companies for a specific product, from all producers. Let's say it is automobiles sold in the USA.
To get Ford's market share, divide the total sales of cars and trucks by Ford and its subsidiaries (Mercury; Lincoln) by the total revenue from car and truck sales in the USA by ALL companies. The answer will be a fraction like 15%.
You could also compute market share using data on the number of units sold, instead of dollar amount, but the answer would be about the same. In the case of manufactured products, the data could come from either retailers or producers.