We propose a method for measuring the systemic importance of interconnected banks. In order to capture contributions to system-wide risk, our measure accounts fully for the extent to which a bank (i) propagates shocks across the system and (ii) is vulnerable to propagated shocks. An empirical implementation of this measure and a popular alternative reveals that interconnectedness is a key driver of systemic importance. However, since the two measures reflect the impact of interbank borrowing and lending on system-wide risk differently, they can disagree substantially about the systemic importance of individual banks.

Funding liquidity risk has played a key role in all historical banking crises. Nevertheless, a measure for funding liquidity risk based on publicly available data remains so far elusive. We address this gap by showing that aggressive bidding at central bank auctions reveals funding liquidity risk. We can extract an insurance premium from banks’ bids which we propose as a measure of funding liquidity risk. Using a unique data set consisting of all bids in all auctions for the main refinancing operation conducted at the ECB between June 2005 and October 2008 we find that funding liquidity risk is typically stable and low, with occasional spikes especially around key events during the recent crisis. We also document downward spirals between funding liquidity risk and market liquidity. As measurement without clear definitions is impossible, we initially provide definitions of funding liquidity and funding liquidity risk.