The physics of a many-particle system is determined by the correlations in its quantum state. Therefore, analyzing these correlations is the foremost task of manybody physics. Any 'a priori' constraint for the properties of the global vs. the local states-the so-called marginals-would help in order to narrow down the wealth of possible solutions for a given many-body problem, however, little is known about such constraints. We derive an equality for correlation-related quantities of any multipartite quantum system composed of finite-dimensional local parties. This relation defines a necessary condition for the compatibility of the marginal properties with those of the joint state. While the equality holds both for pure and mixed states, the pure-state version containing only entanglement measures represents a fully general monogamy relation for entanglement. These findings have interesting implications in terms of conservation laws for correlations, and also with respect to topology.Correlations between different parts of manyparticle quantum systems are manifestly different from their classical counterparts. The hallmark of the latter is that, if the global state is completely known, so are the local states, that is, the individual states of each particle. For quantum states this may be different: Even if the global state is known with certainty, there may be no information whatsoever regarding the local states such as, for example, in maximally entangled states of two d-dimensional systems [1,2].Often, different degrees of departure from the classical behavior are distinguished, namely entanglement, steerability, and nonlocality [3]. While all these correlation types are based on en-