Scholars often conflate the concepts of pooling (how states make collective decisions) and delegation (authorizing an international body to act) in examining the authority of intergovernmental organizations (IGOs). We clarify the difference by showing how states “soft pool” decision-making through informal intergovernmental organizations (IIGOs) without creating legal obligations or delegating authority. IIGOs such as the G-groups are growing in prevalence and importance because soft pooling allows states to make collective decisions that are politically binding in nonlegal ways. We examine organizational characteristics of IIGOs that allow states to minimize sovereignty costs while cooperating through soft pooling – including the use of consensus to express shared expectations through declarations and memoranda of understanding and administrative structures such as rotating chairs to avoid delegating to an independent secretariat. We review these understudied organizational alternatives, explaining how soft pooling makes IIGOs authoritative even as states retain sovereignty.