Before 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 raire.
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 . The second objective leads to requiring consistency of capital adequacy tests across jurisdictions. Of particular importance in this respect are capital adequacy tests that remain invariant under a change of num\'{eraire.