Inadequate funding levels are a major impediment to effective global biodiversity conservation and are likely associated with recent failures to meet United Nations biodiversity targets. Some countries are more severely underfunded than others and therefore represent urgent financial priorities. Now a MacArthur-supported study published in the Proceedings of the National Academy of the Sciences identifies countries where funding is below expected levels. The 40 most severely underfunded countries contain nearly one-third of all threatened mammals. It also finds that small funding increases could achieve big improvements in global conservation.