The proportion of a market taken by one producer. Market share can be measured in terms of volume of sales, for example company X sold 40% of the automobiles sold last month in the uk market. Or it can be measured as the value of sales, for example company X sold 30% of the total value of all automobiles sold in the uk market last month. Or it could be measured in terms of output by volume or value. For example, company X could have produced 50% of all the automobiles made in the uk even though its uk market share was 30% because it exported automobiles to other markets while some automobiles sold in the uk were produced in other countries.