These seemingly identical measures actually differ in important ways. One of them is the degree to which regulators wish to be transparent about what their concerns are: the nature of the vulnerability may not be fully disclosed in case a).
Another is the impact on market perceptions: compared with their foreign peers, domestic banks would look relatively better capitalised in cases a) and b), while they would be perceived as relatively undercapitalised in c). The euro-area configuration, with the ECB-SSM in a position to top up national measures, goes in the direction of assuaging political economy concerns of this kind.