An individual’s purchasing power represents their ability to acquire goods and services based on their disposable income, expressed in constant euros. Laurent Bertrandrias and Alexandre Lapeyre emphasize that purchasing power is intrinsically linked to the exercise of freedom. While a person can technically buy a certain quantity of goods with their wealth, there is no guarantee that they will fully utilize it. Thus, any decrease or stagnation in income combined with an increase in prices can be perceived as a restriction of individual freedom. This is why major retailers place so much emphasis on purchasing power, positioning it at the heart of their communication strategy.

In the field of competitive analysis, the European Commission defines purchasing power as the ability of one or more buyers, based on their economic weight in the relevant market, to negotiate favorable purchasing terms with their suppliers. This concept is of paramount importance in assessing competition, as influential buyers can influence the pricing policies of dominant sellers, thereby establishing a balance of power in the relevant market. However, it is crucial to note that purchasing power does not always lead to positive outcomes. For example, when a powerful buyer faces weaker sellers, the consequences can be worse than if the buyer lacked such power. The effects of a buyer’s purchasing power also depend on their ability to influence the downstream market in terms of sales.