ARBITRAGE BOUNDS FOR PRICES OF WEIGHTED VARIANCE SWAPS

We develop a theory of robust pricing and hedging of a weighted variance swap given market prices for a finite number of co‐maturing put options. We assume the put option prices do not admit arbitrage and deduce no‐arbitrage bounds on the weighted variance swap along with super‐ and sub‐replicating strategies that enforce them. We find that market quotes for variance swaps are surprisingly close to the model‐free lower bounds we determine. We solve the problem by transforming it into an analogous question for a European option with a convex payoff. The lower bound becomes a problem in semi‐infinite linear programming which we solve in detail. The upper bound is explicit. We work in a model‐independent and probability‐free setup. In particular, we use and extend Föllmer's pathwise stochastic calculus. Appropriate notions of arbitrage and admissibility are introduced. This allows us to establish the usual hedging relation between the variance swap and the “log contract” and similar connections for weighted variance swaps. Our results take the form of a FTAP: we show that the absence of (weak) arbitrage is equivalent to the existence of a classical model which reproduces the observed prices via risk‐neutral expectations of discounted payoffs.     

1917–2017: The Geopolitical Legacy of the Russian Revolution

The essays collected in this forum discuss the geopolitical legacy of the Russian Revolution of 1917, one of the most momentous political events of the twentieth century. From a range of different academic disciplines and perspectives, the authors consider how the profound transformations in society and politics were refracted through space and geography, and how enduring these refractions proved to be. The authors focus on three themes that have been dominant in Russian affairs over the past century: 1)the problem of center-periphery relations, 2)the civilizational dynamics of Russia’s self-identification in relation to Europe and to Asia, and 3)the geopolitics of national identity.     

Comparative randomized inverse sampling

According to previous literature, we define randomized inverse sampling for comparing two treatments with respect to a binary response as the sampling that stops when a total fixed number of successes, irrespective of the treatments, are observed. We have obtained elsewhere the asymptotic distributions for the counting variables involved and have shown them to be equivalent to the corresponding asymptotic distributions for multinomial sampling. In this paper, we start deriving the same basic results using different techniques, and we then show how they give rise to genuinely novel procedures when translated into finite sample approximations. As the main example, a novel confidence interval for the logarithm of the odds ratio of two success probabilities can be constructed in the case of comparative randomized inverse sampling. Some advantages over the standard multinomial sampling in terms of coverage probabilities are visible when no adjustment for cells with zero counts is applied; otherwise, the two sampling schemes appear to be fairly equivalent. This is a reassurance that under certain circumstances, inverse sampling can be safely chosen over more traditional sampling schemes.     

Urban Warfare Ecology: A Study of Water Supply in Basrah

This article assesses the impact of armed conflict on the drinking water service of Basrah from 1978 to 2013 through an ‘urban warfare ecology’ lens in order to draw out the implications for relief programming and relevance to urban studies. It interprets an extensive range of unpublished literature through a frame that incorporates the accumulation of direct and indirect impacts upon the hardware, consumables and people upon which urban services rely. The analysis attributes a step‐wise decline in service quality to the lack of water treatment chemicals, lack of spare parts, and, primarily, an extended ‘brain‐drain’ of qualified water service staff. The service is found to have been vulnerable to dependence upon foreign parts and people, ‘vicious cycles’ of impact, and the politics of aid and of reconstruction. It follows that practitioners and donors eschew ideas of relief–rehabilitation–development (RRD) for an appreciation of the needs particular to complex urban warfare biospheres, where armed conflict and sanctions permeate all aspects of service provision through altered biological and social processes. The urban warfare ecology lens is found to be a useful complement to ‘infrastructural warfare’ research, suggesting the study of protracted armed conflict upon all aspects of urban life be both deepened technically and broadened to other cases.     

Achievements and gaps in tef productivity improvement practices in the marginal areas of Northern Ethiopia: implications for future research directions

Tef is the most important crop in Ethiopia and is well-adapted to growing environments, but grain yields are low. The government is therefore promoting the adoption of improved varieties, inorganic fertilizers and new planting techniques. This study gathered information on the use of new agronomic practices and barriers to their adoption through a semi-structured questionnaire administered to 60 farmers or respondents from each of 4 districts of Tigray region in northern Ethiopia viz Laelay-Maichew, Medebay-Zana, Ahferom and Alamata. Data were coded and analysed using SPSS software. Except for animal feed and crop rotation, there were significant differences between districts in the relative importance of several criteria for different uses. Improved varieties were used by the majority of respondents in all districts and fertilizers in all except Alamata where severe moisture stress dictated the choice of variety and reduced fertilizer application. Weed control was mainly by hand except in Alamata where chemical control was common because of the predominance of broad-leaved weeds. Transplanting maximized the yield of tef, but a cost–benefit analysis showed that row sowing was more profitable. The study concluded that new varieties better adapted to the likelihood of reduced rainfall and that respond efficiently to fertilizer inputs need to be developed. Until suitable technologies are available, high labour costs would in part dictate some agronomic practices, even if this led to lower yields.     

Creating an Environment for Economic Growth: Creativity,Entrepreneurship or Human Capital?

Scholars and policymakers interested in the growth and prosperity of regions have long recognized that talent and knowledge are fundamental. Yet the question is what types of talent are needed in a growing twenty‐first‐century economy: human capital, creativity and innovation, or entrepreneurship? The latter we define broadly to include any type of risk taking, and not only radical innovation. The literature does not clearly point to one factor as being the most essential. This study assesses this question separately for rural and urban United States (US) counties. We find that human capital––measured by educational attainment––is considerably more conducive to employment growth than the share of creative occupations. Likewise, the share of small and medium businesses is also very conducive to local growth, although this does not apply to the self‐employment share. Rural and urban areas experience similar patterns, although the magnitude thereof tends to be larger for urban counties, whereas high‐technology employment share has had a positive effect in rural areas. Policy conclusions suggest that enhancing small business development and increasing educational attainment are the two strategies that are most likely to succeed.     

Methods for delivering complex social services: exploring adaptive management and regulation in the Australian National Disability Insurance Scheme

In the wake of new public management, and with the emergence of new public governance, a number of challenges remain unsolved in the field of public service governance and management. In this paper, we use the example of the Australian National Disability Insurance Scheme to show how we might deal with the design and implementation of a public service reform within the context of new public governance. We argue that governments need to develop greater openness to risk and policy experimentation during implementation. We therefore propose an adaptive system architecture that could support such risk taking.     

Cross‐border mergers and acquisitions: The role of private equity firms

Research summary: We show that private equity ownership (“PE backing”) of the acquirer is a signal of deal quality in cross‐border takeovers. As such, PE‐backed acquirers experience higher announcement returns in cross‐border takeovers, but only if targets are in poor information environments. We show that PE backing is a positive market signal because of PE firms' experience and networks that result from prior deals in target countries. We document that the market correctly anticipates that operating performance of PE‐backed acquirers increases as a result of cross‐border mergers and acquisitions (M&A). Managerial summary: We study cross‐border acquisitions by acquirers that are partially owned by private equity firms (“PE backing”). Cross‐border acquisitions are challenging as acquirers often have little information about targets. We document that investors react positively to cross‐border deals of PE‐backed acquirers—their stock prices increase upon deal announcements. However, this is only the case if targets are in countries with poor information environments. This is because PE backing allows acquirers to access PE firms' deal experience and networks. This makes it easier to identify and evaluate good targets, making it more (less) likely that a deal eventually creates (destroys) value. Consistent with this, we find that earnings of PE‐backed acquirers increase after buying targets in poor information environments. Copyright © 2016 John Wiley & Sons, Ltd.