Marco Bardoscia, Gerardo Ferrara and Nicholas Vause
Participants in derivative markets collect collateral from their counterparties to help secure claims against them should they default. This practice has become more widespread since the 2007-08 financial crisis, making derivative markets safer. However, it increases potential ‘margin calls’ for counterparties to top up their collateral. If future calls exceed available liquid assets, counterparties would have to borrow. Could money markets meet this extra demand? In a recent paper, we simulate stress-scenario margin calls for many of the largest derivative-market participants and see if they could meet them – including because of payments from upstream counterparties – without borrowing. We compare the sum of any shortfalls with daily cash borrowing in international money markets.
Sterling money markets are a critical part of the plumbing of the UK financial system. They act as the main conduit for short-term borrowing and lending between banks, and a whole range of other institutions, financial and non-financial. And the ebb and flow of activity in sterling money markets is also crucial to the Bank of England as the first stage in the transmission mechanism of monetary policy, linking changes in the Bank’s policy rate – Bank Rate – to activity and prices in the wider economy. So when things go wrong in this market, as they did during the financial crisis, the effects reach into every part of the UK economy and, given the significant role of international banks in London, beyond. So what happened in the autumn of 2008, and why?
Over the last twenty years, the BOE has carried out a number of reforms to its operational framework which have been partly intended to reduce money market volatility. My analysis suggests that these have been successful. Overnight volatility fell by around 90% since the early 2000s and much of this can be explained by the BOE’s reforms. But I find little evidence that this affected the volatility of term rates, which are more important than overnight rates for monetary policy transmission. Therefore, central banks might consider giving less priority to money market volatility when designing their future operating frameworks.