A liquidity risk index as a regulatory tool for systemically important banks? An empirical assessment across two financial crises

We provide an assessment of the IMF suggestion, based on Severo (2012), to use an index of systemic liquidity risk (SLRI) that could help to estimate a Pigouvian tax on large banks for the externality on the international banking system out of their risk exposure. To this end we compute a parsimonious and fully documented SLRI and investigate its statistical significance in explaining level and variability of stock returns for a group of large international banks during the subprime financial and the Eurozone sovereign debt crises. The empirical investigation consistently fails to detect, within and across the two crises, a core group among the systemically important banks listed by the Financial Stability Board and thus supports a sceptical assessment of the proposal.