Dan Georgescu and Nicholas J. Higham
Correlation matrices arise in many applications to model the dependence between variables. Where there is incomplete or missing information for the variables, this may lead to missing values in the correlation matrix itself, and the problem of how to complete the matrix. We show that some of these practical problems can be solved explicitly, via simple formulae, and we explain how to use mathematical tools to solve the more general problem where explicit solutions may not exist. “Simple” is, of course, a relative term, and the underlying matrix algebra and optimization necessarily makes this article more mathematically sophisticated than the typical Bank Underground post.
Graeme Douglas, Nicholas Vause and Joseph Noss
Risky asset prices plummeted following the collapse of Lehman Brothers in 2008. Whilst driven partly by deteriorations in fundamental news, these falls were amplified by ‘flighty’ investors that sold at the first signs of trouble. Conventional wisdom dictates that life insurers, with their long-term investment horizons, are better placed than most to ‘lean against the wind’ by looking through short-term fluctuations in asset prices. They could thereby stabilise prices when others are selling. But the structure of regulations can greatly influence insurers’ investment incentives. Using our model of insurers’ asset allocations, we find that new ‘Solvency II’ regulations reduce UK life insurers’ willingness to act as the white knights of financial markets, particularly in the face of falling interest rates.
Jon Frost and Julia Giese.
A seismic shift is occurring in the European financial system. Since 2008, the aggregate size of bank balance sheets in the EU is essentially flat, while market-based financing has nearly doubled. This shift presents challenges for macroprudential policy, which has a mandate for the stability of the financial system as a whole, but is still focused mostly on banks. As such, macroprudential policymakers are focusing increasing attention on potential systemic risks beyond the banking sector. Drawing from a European Systemic Risk Board (ESRB) strategy paper which we helped write along with five others, we take a step back and set out a policy strategy to address risks to financial stability wherever they arise in the financial system.
David Elliott, Chris Jackson, Marek Raczko and Matt Roberts-Sklar.
Oil prices have fallen by more than 50% since mid-2014. For much of this period, financial market measures of both short-term and longer-term inflation expectations appear to have mirrored moves in oil prices, particularly in the US and euro area. But how strong is the relationship between oil prices and financial market inflation expectations, and what should we make of it?
Dan Georgescu & Manuel Sales.
Capital requirements for financial institutions are typically calculated using a statistical model and a risk measure such as VaR, whereas stress tests designed by regulators and risk managers are often based on subjective scenarios with no associated probability level. The stress test cannot therefore be easily linked to the capital measure. Taking insurance as an example, we show how to establish the link using intuitive tools which (i) respect the stress test designer’s intuition about causal direction, (ii) can be calibrated to pre-determined parameters such as correlations between risks, and (iii) can be easily communicated to and challenged by non-technical audiences.
Neha Jain, James O’Reilly & Nicholas Silk
In 2020 Google plans to launch a self-driving car which has already driven nearly one million miles without causing an accident; it doesn’t get tired and irritable, swerve into lamp posts or require a driving test. The in-built chauffeur comes in the form of a rotating LIDAR laser taking 1.3 million recordings per second, and it’s a better driver than you. By eliminating the element of human blunders, driverless cars are forecast to reduce motor accidents by up to 90% in the US according to McKinsey. That might imply a substantial impact on the insurance industry, with liability potentially shifting to car manufacturers. Such developments would pose challenging questions for the PRA in regulating UK insurance firms.