Evidence · Brand growth

Light vs heavy buyers: what the research shows

Most of a brand's buyers buy it rarely. The heaviest 20% of buyers usually account for around half of a brand's sales rather than 80%, and many of them buy less the next year. Buyers who purchase a brand once a year or less supply about a third of its volume over five years. Concentration can be higher in retail spending, so the exact share depends on the setting, but the light-buyer majority is consistent.

Definition

Light buyers purchase a brand or category infrequently in a given period; heavy buyers purchase it often. In repeat-purchase markets purchase rates vary widely between people, so any brand's buyer base is dominated by light buyers, while a smaller group of heavy buyers also buys competing brands. The Pareto or 80/20 rule is the popular claim that the top fifth of customers produces most sales.

What the research finds

Most buyers are light buyers

Because purchase rates differ widely across consumers, a brand's buyers in any period are mostly occasional. Across more than 850 brands in almost 60 categories, people who bought a brand once a year or less made up about 62% of its buyers over five years.^[1]^[2]

Ultra-light buyers add up

Although each of these ultra-light buyers buys very rarely, together they accounted for roughly 32% of purchase occasions and about 31% of a brand's sales volume and value over five years.^[2]

Closer to 60/20 than 80/20

For brands, the heaviest 20% of buyers generally contribute not much more than half of sales. About half of one year's heavy buyers fall out of the top 20% the next year, while light and non-buyers contribute more than before. This evidence is presented in a working paper that updates earlier work by the same authors.^[3]

Concentration depends on the setting

In more than 550 million transactions at an East Asian department store chain, the top 20% of spenders produced 71% of revenue, but the stability of that group from year to year ranged from 11% to 74% across departments. Across U.S. households from 2009 to 2024, the top 20% accounted for about half of category spending, a stable pattern; packaged goods did not represent spending inequality in other categories, and a 10/40 ratio is proposed as a complementary measure.^[4]^[5]

Growth depends on reaching light and non-buyers

Since heavy buyers are few, shared with competitors and prone to buying less the following year, brand growth has to come largely from light buyers and non-buyers. This conclusion is argued mainly in a book and a working paper from the same research group.^[6]^[3]

How strong is the evidence?

That light buyers dominate a brand's customer base follows from well-established models of repeat buying and has been measured across hundreds of brands. The exact Pareto share depends on the period, how buyers are ranked, brand size and category, and retail and whole-category data show higher concentration than brand-level packaged-goods data. Heavy and light are relative labels, so comparisons across categories need care. The case that growth must come from light buyers, and the 60/20 figure, are argued mainly by one research group in a book and a working paper; independent studies confirm the light-buyer majority but find concentration varies by setting.

Claims tested against the evidence

Do loyalty programs change buying behaviour? Contradicted by the evidence

References

Gerald J. Goodhardt, Andrew S. C. Ehrenberg, Christopher Chatfield (1984). The Dirichlet: A Comprehensive Model of Buying Behaviour. Journal of the Royal Statistical Society. Series A (General).
Afsana Hossain, Zachary William Anesbury, Carl Driesener, Giang Trinh (2023). Valuing the Contribution of Ultra-Light Buyers. Journal of Consumer Behaviour.
Byron Sharp, Jenni Romaniuk, Charles Graham (2019). Marketing’s 60/20 Pareto Law. SSRN Electronic Journal.
Arry Tanusondjaja, Jenni Romaniuk, Magda Nenycz‐Thiel, Mototaka Sakashita, Vijay Viswanathan (2022). Examining Pareto Law across department store shoppers. International Journal of Market Research.
Barak Libai, Michael Haenlein, Sarah Gelper (2026). Is the Pareto a principle? A longitudinal exploration of inequality in category-level consumer spending. International Journal of Research in Marketing.
Byron Sharp (2010). How Brands Grow: What Marketers Don't Know. Oxford University Press.

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