Many multiagent systems rely on collective decision-making among self-interested agents, which raises deep questions about coalition formation and stability. We study social choice with endogenous, outcome-contingent transfers, where agents voluntarily form contracts that redistribute utility depending on the collective decision, allowing fully strategic, incentive-aligned coalition formation. We show that under consensus rules, individually rational strong Nash equilibria (IR-SNE) always exist, implementing welfare-maximizing outcomes with feasible transfers, and provide a simple, efficient algorithm to construct them. For more general anonymous, monotonic, and resolute rules, we identify necessary conditions for profitable deviations, sharply limiting destabilizing coalitions. By bridging cooperative and noncooperative perspectives, our approach shows that transferable utility can achieve core-like stability, restoring efficiency and budget balance even where classical impossibility results apply. Overall, this framework offers a practical and robust way to coordinate large-scale strategic multiagent systems.

翻译：许多多智能体系统依赖于自利智能体之间的集体决策，这引发了关于联盟形成与稳定性的深层问题。我们研究具有内生性、结果依存的转移机制的社会选择问题，其中智能体自愿形成根据集体决策结果重新分配效用的契约，从而实现完全策略性、激励相容的联盟形成。我们证明在共识规则下，个体理性的强纳什均衡（IR-SNE）始终存在，能够通过可行的转移实现福利最大化结果，并给出一种简单高效的构建算法。对于更一般的匿名、单调且确定性的规则，我们界定了有利可图的偏离所需必要条件，从而严格限制了破坏稳定的联盟形成。通过融合合作与非合作博弈视角，我们的方法表明可转移效用能够实现类核心稳定性，即使在经典不可能性定理适用的场景中也能恢复效率与预算平衡。总体而言，该框架为协调大规模策略性多智能体系统提供了一种实用且稳健的途径。