A simple prudential-effort foundation for the financial trilemma
用一个简单的审慎努力模型，为金融三难困境提供了唯一均衡基础，说明当金融一体化与国家政策自主性都很高时，国家监管者提供的审慎努力不足，无法实现最优稳定，从而需要超国家审慎安排。
The “financial trilemma” asserts that deep financial integration, purely national financial policies and financial stability cannot simultaneously be achieved. Existing formalisations employing ex post burden-sharing games imply the trilemma result hinges on equilibrium selection. We develop a minimal ex ante prudential-effort model where financial integration amplifies cross-border crisis risk and national regulators internalise only part of global losses. The unique symmetric Nash equilibrium underprovides prudential effort and cannot deliver first-best stability when both integration and national policy autonomy are high. That provides a unique-equilibrium foundation for the financial trilemma and clarifies when supranational prudential arrangements are needed.