It is the share of an individual consumer's expenditures in an industry or retail sector that is spent at one company.
Whereas market share describes the percentage of all customers that patronize a company relative to the industry total, the patronage concentration ratio describes the percentage of one customer's patronage going to a company, relative to that person's spending in the industry.
That is, market share is the aggregate or macro version of the patronage concentration ratio.
In particular, patronage concentration involves trading off economic resources against product assortment, and spatial and temporal benefits.
It has been shown that patronage decisions are associated with consumer characteristics that are suggestive of heterogeneous cost–benefit tradeoffs and opportunity costs of time.