A simple hypergraph H with vertex set X and edge set E is representable as a family of Von Neumann- Morgenstern stable sets -or VNM- if there exists an irreflexive simple digraph D with vertex set X such that each edge of H is a VNM--stable set of D. It is shown that a simple hypergraph H is VNM if and only if each edge of H is a maximal clique of the conjugation graph of H. A related algorithm that identifies finite VNM-hypergraphs is also provided.