Double Jeopardy Beyond FMCG: Empirical Regularities and Strategic Implications in the E-Commerce Sector

Abstract: The double jeopardy (DJ) law—one of marketing’s strongest empirical patterns—shows that smaller brands have both fewer buyers and slightly lower loyalty, with market share driven mainly by penetration. Originally observed in FMCG markets and other consumer and b2b goods, this pattern also appears in digital commerce. Examining online fashion retail platforms and their product categories, the paper shows that differences in market share are explained primarily by how many buyers each site or category attracts, not by higher repeat rates. Even in environments with low switching costs and algorithmic personalization, consumer behavior follows the same probabilistic, exposure-driven structure found in traditional markets: growth comes from acquiring more customers rather than increasing loyalty among existing ones. This highlights the universality of the DJ law and the central role of visibility in shaping repeat buying. For e-commerce managers, the strategic implication is clear—focus on expanding buyer penetration through marketing, recommendations, and category management, as loyalty naturally follows increased exposure. Keywords: Double Jeopardy, E-commerce, Ehrenberg