It can be expressed as a company's sales revenue (from that market) divided by the total sales revenue available in that market. It can also be expressed as a company's unit sales volume (in a market) divided by the total volume of units sold in that market.
Market share is one of the most common objectives used in business. (Other objectives include return on investment (ROI), return on assets (ROA), and target rate of profit). The main advantage of using market share is that it abstracts from industry wide macroenvironmental variables such as the state of the economy, or changes in tax policy.
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