The system switches to a low-liquidity equilibrium. These liquidity droughts were perhaps the defining feature of the financial crisis during 2007 and 2008. In the model, the likelihood of such systemic liquidity crises depends critically on two key structural characteristics of the financial system – the two c’s: concentration and complexity. The greater the concentration within the financial system, the greater the potential for systemic collapse as larger banks spread a disproportionate amount of financial pain around a densely networked financial system. A greater degree of system complexity has a similar effect, creating more channels for contagion and heightening banks’ incentives to hoard liquidity when the weather worsens. The two c’s are very much features of today’s financial system. On the face of it, that bodes ill for future systemic crises. So what role might policy play in avoiding those crises? The model provides a test-bed to consider a range of policy options, including for haircuts policy. An illustrative policy experiment, based on a simulation of the model in which haircuts spike sharply, is shown in Chart 1. Up the vertical axis is a measure of the probability of a systemic liquidity crisis. Along the horizontal axis is the initial size of the haircut on secured financing transactions. The three lines trace three policy options. Consider first the “baseline” path without policy intervention. Provided haircuts remain high come rain or shine – in the example, above around 20% – the probability of a liquidity crisis remains very low.
Transparency enhances the effectiveness of monetary policy by helping to guide the expectations of economic agents and bring them into line with policy objectives and actions. For these reasons, the ECB has striven to be as transparent as possible, communicating clearly, and by a variety of means, its policy objective, its strategy, its assessment of the economic situation, and its view of the outlook for price stability and associated risks. There is no doubt, however, that communication is a challenging task. I can assure you that we at the ECB – in light of the mandate that was assigned to us by the Maastricht Treaty and the trust and credibility we have earned from more than 313 million citizens – take this challenge very seriously. *** Chairman, Governors, Professors, dear friends, I have on behalf of the Executive Board and Governing Council of the ECB to thank all of you for having accepted our invitation and for having contributed so actively to the discussions. The ECB considers important to permanently guard against complacency and to remain open to criticisms and suggestions, to take regularly stock of the advances of academic research. I thank you for your attention. 2  BIS Review 110/2006