Market penetration is one of the four growth strategies of the Product-Market Growth Matrix as defined by Ansoff. Market penetration occurs when a company enters/penetrates a market in which current products already exist. The best way to achieve this is by gaining competitors' customers (part of their market share). Other ways include attracting non-users of your product or convincing current clients to use more of your product/service (by advertising etc.). Ansoff developed the Product-Market Growth Matrix to help firms recognize if there was any advantage of entering a market. The other three growth strategies in the Product-Market Growth Matrix are:
"Penetration is a measure of brand or category popularity. It is defined as the number of people who buy a specific brand or a category of goods at least once in a given period, divided by the size of the relevant market population." [1]
The penetration that brands and products have can be recorded by companies such as ACNielsen and TNS who offer panel measurement services to calculate this and other consumer measures. In these cases penetration is given as a percentage of a country's households who have bought that particular brand or product at least once within a defined period of time.