X-consumers are the extremely frequent (top 2–3%) users who typically consume 25% of a product category. This article shows how to use fuzzy-set qualitative comparative analysis (QCA) to provide “causal recipes” sufficient for profiling X-consumers accurately. The study extends Dik Twedt’s “heavy-half” product users for building theory and strategies to nurture or control X-behavior. The study here applies QCA to offer configurations that are sufficient in identifying “whales” and “jumbo shrimps” among X-casino gamblers. The findings support the principle that not all X-consumers are alike. The theory and method are applicable for identifying the degree of consistency and coverage of alternative X-consumers among users of all product-service category and brands.