10  BIS central bankers’ speeches  the relatively early stages of exploring the utility of different approaches to measuring both these variables, and we do not have a single well-established metric for either variable today. As already noted in my discussion of systemic risk surcharges, the quantification of a “systemic loss given default” seems particularly challenging. A second issue is time contingency.
Consider an acquisition that, in calm times, seems pretty clearly to increase the systemic footprint of an already large, interconnected acquiring institution without having a material positive effect on the resilience of that firm during a stress period. That starkly stated circumstance would seem a prototypical case in which a conclusion of an adverse effect on financial stability would be reached.