Working Paper No. 597
By David Murphy, Michalis Vasios and Nicholas Vause
The requirement to post initial margin on derivatives transactions is a key feature of the post-crisis reforms of the OTC derivatives markets. Initial margin requirements are usually determined by risk-based models. These models typically require increased margin in stressed conditions: they are procyclical. This procyclicality causes a liquidity burden on market participants which sometimes falls when they are least able to bear it. In this paper we study a variety of tools which have been proposed to mitigate the procyclicality of initial margin requirements. Three of these tools are proposed in European regulation; the other two are new proposals which offer attractive procyclicality mitigation features. The behaviour of all five tools is studied in a simulation framework. We examine the extent to which each tool mitigates procyclicality, and at what cost in demanding unnecessary margin compared to a benchmark unmitigated model. Our findings indicate that all of the tools are useful in mitigating procyclicality to some extent, but that the optimal calibration of each tool in a particular situation depends on the relative weights placed by the modeller on the objectives of minimizing procyclicality on the one hand and minimizing undesirable overmargining in periods of low volatility on the other. This suggests that it may be appropriate to consider moving from tools-based procyclicality regulation to one based on the desired outcomes.
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