Market share is the percentage of a market (defined in terms of either units or revenue) accounted for by a specific entity. In a survey of nearly 200 senior marketing managers, 67 percent responded that they found the "dollar market share" metric very useful, while 61% found "unit market share" very useful.

Marketers need to be able to translate sales targets into market share because this will demonstrate whether forecasts are to be attained by growing with the market or by capturing share from competitors. The latter will almost always be more difficult to achieve. Market share is closely monitored for signs of change in the competitive landscape, and it frequently drives strategic or tactical action.

Increasing market share is one of the most important objectives of business

Business

A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...

. The main advantage of using market share as a measure of business performance is that it is less dependent upon macroenvironmental variables

Environmental scanning

Environmental scanning is one component of the global environmental analysis. Environmental monitoring, environmental forecasting and environmental assessment complete the global environmental analysis. Environmental scanning refers to the macro environment.The global environment refers to the...

 such as the state of the economy or changes in tax policy

Tax policy

Tax policy is the government's approach to taxation, both from the practical and normative side of the question.-Philosophy:Policymakers debate the nature of the tax structure they plan to implement and how they might affect individuals and businesses .The reason for such foitution effect]],...

. However, increasing market share may be dangerous for makers of fungible

Fungibility

Fungibility is the property of a good or a commodity whose individual units are capable of mutual substitution, such as crude oil, wheat, precious metals or currencies...

 hazardous products, particularly products sold into the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 market, where they may be subject to market share liability

Market share liability

Market share liability is a legal doctrine unique to the law of the United States that allows plaintiffs injured by fungible products to apportion liability among the manufacturers according to their share of the market for the injurious product.-Origins:...

.

Purpose

Market share is a key indicator of market competitiveness—that is, how well a firm is doing against its competitors. This metric, supplemented by changes in sales revenue, helps managers evaluate both primary and selective demand in their market. That is, it enables them to judge not only total market growth or decline but also trends in customers’ selections among competitors. Generally, sales growth resulting from primary demand (total market growth) is less costly and more profitable than that achieved by capturing share from competitors. Conversely, losses in market share can signal serious long-term problems that require strategic adjustments. Firms with market shares below a certain level may not be viable. Similarly, within a firm’s product line, market share trends for individual products are considered early indicators of future opportunities or problems.

It is generally necessary to commission market research

Market research

Market research is any organized effort to gather information about markets or customers. It is a very important component of business strategy...

 (generally desk/secondary research

Secondary research

Secondary research involves the summary, collation and/or synthesis of existing research rather than primary research, where data is collected from, for example, research subjects or experiments....

) to determine. Sometimes, though, one can use primary research

Primary research

Primary research consists in research to collect original primary data. It is often undertaken after the researcher has gained some insight into the issue by collecting secondary data...

to estimate the total market size and a company's market share.

Construction

Market share: The percentage of a market accounted for by a specific entity.

Unit market share: The units sold by a particular company as a percentage of total market sales, measured in the same units.

Unit market share (%) = 100 * Unit sales (#) / Total Market Unit Sales (#)

This formula, of course, can be rearranged to derive either unit sales or total market unit sales from the other two variables, as illustrated in the following:

Unit sales (#) = Unit market share (%) * Total Market Unit Sales (#) / 100

Total Market Unit Sales (#) = 100 * Unit sales (#) / Unit market share (%)

Revenue market share: Revenue market share differs from unit market share in that it reflects the prices at which goods are sold. In fact, a relatively simple way to calculate relative price is to divide revenue market share by unit market share.

Revenue market share (%) = 100 * Sales Revenue ($) / Total Market Sales Revenue($)

As with the unit market share, this equation for revenue market share can be rearranged to calculate either sales revenue or total market sales revenue from the other two variables.

Methodologies

Although market share is probably the single most important marketing metric, there is no generally acknowledged best method for calculating it. This is unfortunate, as different methods may yield not only different computations of market share at a given moment, but also widely divergent trends over time. The reasons for these disparities include variations in the lenses through which share is viewed (units versus dollars), where in the channel the measurements are taken (shipments from manufacturers versus consumer purchases), market definition (scope of the competitive universe) and measurement error.