Before revision:  We characterize capital adequacy tests that satisfy surplus and num\'{e invariance, establish an intimate link between these requirements, and highlight an inherent tension between the ability to meet them and the desire to give credit for diversification.
After revision:  We characterize capital adequacy tests that satisfy surplus and num\'eraire invariance, establish an intimate link between these requirements, and highlight an inherent tension between the ability to meet them and the desire to give credit for diversification.