Beyond the Sharpe ratio: An application of the Aumann–Serrano index to performance measurement

We propose a performance measure that generalizes the Sharpe ratio. The new performance measure is monotone with respect to stochastic dominance and consistently accounts for mean, variance and higher moments of the return distribution. It is equivalent to the Sharpe ratio if returns are normally distributed. Moreover, the two performance measures are asymptotically equivalent as the underlying distributions converge to the normal distribution. We suggest a parametric and a non-parametric estimator for the new performance measure and provide an empirical illustration using mutual funds and hedge funds data.     

Progressive taxes and firm births

Tax reform proposals in the spirit of the “flat tax” model typically aim to reduce three parameters: the average tax burden, the progressivity of the tax schedule, and the complexity of the tax code. We explore the implications of changes in these parameters for entrepreneurial activity, measured by counts of firm births. The Swiss fiscal system offers sufficient intra-national variation in tax codes to allow us to estimate such effects with considerable precision. We find that high average taxes and complicated tax codes depress firm birth rates, while tax progressivity per se promotes firm births. The latter result supports the existence of an insurance effect from progressive corporate income taxes for risk-averse entrepreneurs. However, implied elasticities with respect to the level and complexity of corporate taxes are an order of magnitude larger than elasticities with respect to the progressivity of tax schedules.     

Risk management strategies - before Hominization and after

Selected examples, ranging from birds to pastoralistic nomads and subsisting peasants, indicate that the higher animals adopt foraging strategies similar to individual decision makers in economies without market (subsistence economies): in contrast to actors in (ideal neoclassical) market economies, maximizing expected utility, they operate in such way as to optimize long-term survival of genetically related groups. This can be seen as a strategy of (maximum) ruin avoidance, played by 'selfish genes'. In the sense of conjectural history the parallelism between risk behaviour of animals and early men may be regarded as the continued existence of principles of natural evolution beyond hominization up to the historical emergence of complex societies where pursuit of surplus production replaced ruin avoidance as the primary orientation in the older subsistence economies.     

Emerging risk of autoignition and fire in underground coal storage

The risk and prevention of autoignition in underground coal storage facilities are reviewed in the light of the recent incidents of smouldering fires. Also, the opportunities are considered on the efficiency of the alternatives to prevent and extinguish closed-space fires. The complexities in avoiding and extinguishing underground fires are highlighted in the case example, describing the observations and outcome of a smouldering coal fire in the storage. The principles of self-heating and most critical factors in spontaneous combustion such as the condition and quality of coal are fairly well known, but usually only provide partial help in fire prevention. The documented cases and the case example suggest that nitrogen injection can be useful for extinguishing controllable fires. Three-phase foams and oxygen-displacing exhaust gases appear preferable against uncontrolled fires, particularly if access to the fire area is limited or impossible. Otherwise, efficient fire extinction during power plant operation can be challenging, as any air ingress tends to feed the fire and results in losses of the extinguishing agent and the heating value of coal. Methods and indicators for detecting and predicting the ignition are discussed, and improvements are suggested to enhance the storage and plant availability.     

Experience and the unexpected: risk and mitigation issues for operating underground storage silos for coal-fired power plant

Observed autoignition events and extinguishing the resulting smouldering fires in an underground storage system of a coal-fired power plant have provided insight into the array of contributing variables, and some experience on quantifying the risk with alternative scenarios of event initiation, progress and potential mitigation. Although the first attempts to quantify the risk suggest high sensitivity to the sequence of action taken after fire alarm, and no similar storage sites really exist, some recommended preventive, corrective and other mitigating activities can be at least partly defined and improved by using the cumulative experience and parallel efforts in other closed or underground storage sites. However, there are also so-called black (or at least grey) swans: unexpected events for which the facility may be poorly prepared for. In the case of the underground storage silos, such an event was experienced when incoming cold coal during a harsh winter season froze the sewer system that normally protects the stored coal from seepage water. With blocked normal bypass, the seepage water found its way to the coal silos and created large clumps of icy coal that blocked the coal conveyors. Although freezing weather is not unusual at high-latitude power plants, the common methods to combat freezing of coal are mainly useful for open storage sites and above-ground transport. Options for mitigation are discussed, as well as the event chain leading to an event that had never previously occurred. The case is discussed from the point of view of options to prepare for rare or unforeseen events.     

Default contagion and systemic risk in loan guarantee networks

This paper studies systemic risk in the Chinese debt market stemming from inter‐corporate loan guarantees using field data from Zhejiang Province. We apply a weighted and directed network model to analyse the implications for default contagion and systemic risk under different stress testing scenarios. The empirical results indicate that the topology of the loan guarantee network is close to a ‘scale‐free’ structure, which is known to be robust against accidental failures but vulnerable to coordinated attacks. Hence, the network is able to cope with idiosyncratic shocks resulting from single company failures, but can easily suffer from more widespread contagion if a group of systemically important companies are hit by a targeted shock. We further demonstrate that within our sample of small and medium‐sized enterprise (SME) companies, increasing leverage reduces network stability and exacerbates the effects of contagion. More lenient bank lending policies increase the survival rate of sample companies and thereby reduce the losses from default contagion.     

Import-Price Uncertainty, Production Decisions, and Relative Factor Shares

The effects of import-price uncertainty on factor income in Switzerland are estimated. The production-theory approach is used to derive the import demand function from an expected utility maximization problem, treating imports as an input to the technology. The model is also used to test for risk aversion and to assess the impact of uncertainty on the volume of imports and gross output. Evidence is found that, for most years, labor has been relatively more vulnerable to uncertainty than has capital.