This chapter provides an in-depth analysis of the insurance guarantee and its usefulness as a legal and economic instrument for securing risks arising in waste management. Given the absence of a uniform regulatory framework, it undertakes a doctrinal inquiry into the legal nature of the insurance guarantee, taking into account divergent legal cultures and the historical evolution of guarantee instruments. A central issue is its classification within contract law, including whether it should be treated as a distinct type of guarantee contract, and how it relates to other guarantee-based mechanisms. The chapter also examines the structural dimension of the insurance guarantee, in particular whether it should be conceptualised as a tripartite legal relationship and how such a construction differs from comparable tripartite arrangements (notably insurance in favour of a third party). To identify the features that define the insurance guarantee, the analysis systematically compares it with institutions serving analogous security functions—especially suretyship, security deposits, bank guarantees, and the insurance contract—each reflecting a different allocation of protection, cost, and functional suitability. In light of the dissertation’s broader aims, the chapter isolates those differences that are decisive when waste holders use these instruments to satisfy financial security requirements imposed by environmental authorities. On this basis, it evaluates the functional value of the insurance guarantee in waste management and delineates the conditions under which it may constitute an effective and economically justified alternative to other forms of financial security.