Network Risk and Key Players: A Structural Analysis of Interbank Liquidity∗ Edward Denbee Christian Julliard Ye Li Kathy Yuan June 4, 2018 Abstract We estimate the liquidity multiplier and individual banks' contribution to systemic liquidity risk in an interbank network using a structural model. Banks borrow liquid- ity from neighbours and update their valuation based on neighbours' actions. When the former (latter) motive dominates, the equilibrium exhibits strategic substitution (complementarity) of liquidity holdings, and a reduced (increased) liquidity multi- plier dampening (amplifying) shocks. Empirically, we find substantial and procyclical network-generated risks driven mostly by changes of equilibrium type rather than net- work topology. We identify the banks that generate most systemic risk and solve the planner's problem, providing guidance to macro-prudential policies. Keywords: financial networks; liquidity; interbank market; key players; systemic risk. ∗We thank the late Sudipto Bhattacharya, Yan Bodnya, Douglas Gale, Michael Grady, Charles Khan, Seymon Malamud, Farzad Saidi, Laura Veldkamp, Mark Watson, David Webb, Anne Wetherilt, Kamil Yilmaz, Peter Zimmerman, and seminar participants at the Bank of England, Cass Business School, Duisenberg School of Finance, Koc University, the LSE, Macro Finance Society annual meeting, the Stockholm School of Economics, and the WFA for helpful comments and discussions. Denbee (ed-
[email protected]) is from the Bank of England; Julliard (
[email protected]) and Yuan (
[email protected]) are from the London School of Economics, SRC, and CEPR; Li (
[email protected]) is from the Ohio State University. This research was started when Yuan was a senior Houblon-Norman Fellow at the Bank of England.