On portfolio optimization: Imposing the right constraints

We reassess the recent finding that no established portfolio strategy outperforms the naively diversified portfolio, 1/N, by developing a constrained minimum-variance portfolio strategy on a shrinkage theory based framework. Our results show that our constrained minimum-variance portfolio yields significantly lower out-of-sample variances than many established minimum-variance portfolio strategies. Further, we observe that our portfolio strategy achieves higher Sharpe ratios than 1/N, amounting to an average Sharpe ratio increase of 32.5% across our six empirical datasets. We find that our constrained minimum-variance strategy is the only strategy that achieves the goal of improving the Sharpe ratio of 1/N consistently and significantly. At the same time, our developed portfolio strategy achieves a comparatively low turnover and exhibits no excessive short interest.     

The US financial crisis,market volatility,credit risk and stock returns in the Americas

We employ the multivariate DCC-GARCH model to identify contagion from the USA to the largest developed and emerging markets in the Americas during the US financial crisis. We analyze the dynamic conditional correlations between stock market returns, changes in the general economy’s credit risk represented by the TED spread, and changes in the US market volatility represented by the CBOE Volatility Index^® (VIX). Our sample includes daily closing prices from January 1, 2002 to December 31, 2015, for the USA and stock markets in Argentina, Brazil, Canada, Chile, Colombia, Mexico, and Peru. We first identify that increases in VIX have a negative intertemporal and contemporaneous relationship with most of the stock returns, and these relationships increase significantly during the US financial crisis. We then find evidence of significant increases in contemporaneous conditional correlations between changes in the TED spread and stock returns. Increases in conditional correlations during the financial crisis are associated with financial contagion from the USA to the Americas. Our findings have policy implications and are of interest to practitioners since they illustrate that during periods of financial distress, US stock volatility and weakening credit market conditions could promote financial contagion to the Americas.

     

Algorithmic market making for options

In this article, we tackle the problem of a market maker in charge of a book of options on a single liquid underlying asset. By using an approximation of the portfolio in terms of its vega, we show that the seemingly high-dimensional stochastic optimal control problem of an option market maker is in fact tractable. More precisely, when volatility is modeled using a classical stochastic volatility model—e.g. the Heston model—the problem faced by an option market maker is characterized by a low-dimensional functional equation that can be solved numerically using a Euler scheme along with interpolation techniques, even for large portfolios. In order to illustrate our findings, numerical examples are provided.     

Wholesale most-favored-nation clauses and price discrimination with negative consumption externalities: equivalence results

Most-favored-nation (MFN) clauses in wholesale contracts have been the subject of recent controversy and renewed antitrust scrutiny. We demonstrate that a vertical environment where MFN clauses may be endogenously adopted shares equivalence properties with an environment where a final goods monopolist sells a good exhibiting negative consumption externalities directly to consumers and is faced with an exogenously imposed uniform pricing requirement. By leveraging these equivalence results, we are able to offer a new and useful framework for assessing the welfare effects of wholesale MFNs and which generates new insights.     

Redistributive effects of the shift from personal income taxes to indirect taxes: Belgium 1988–93

Between 1988 and 1993, the Belgian personal income tax system and the indirect tax system were reformed to a considerable extent. We use microsimulation models to investigate the impact of the reform on the liability progression and the redistributive effect of the combined tax system. The redistributive effect of personal income taxes decreased, notwithstanding an increase in liability progression. For indirect taxes, both the liability regressivity and the reverse redistributive effect have been enhanced. We use recently developed statistical tests to gauge the significance of the observed changes.     

The versatile role of sustainable market entrepreneurs in market transformation: An intervention framework for institutional change

This article investigates in which way sustainable entrepreneurship can generate institutional change that transforms markets towards sustainability. A transformation of models of economic organization and market structures through sustainable entrepreneurship fosters the path towards sustainability. Institutional change involves sustainable market entrepreneurs as institutional entrepreneurs that operate in an effectual manner in different market transformation phases. Sustainable market entrepreneurs while seeking entrepreneurial opportunities simultaneously shape existing market structures and market conditions in different sustainable market transformation phases thereby creating new opportunities. Accordingly, a framework that explains institutional change prompted by sustainable market entrepreneurs in market transformation phases is developed. In this framework, various interventions which encourage sustainable market entrepreneurs to co-create with the stakeholders of their choice are strategized. The provided framework enhances the understanding of the versatile role of sustainable market entrepreneurs and potentially the leverage of their actions towards institutional impact over time.     

The role of evaluation in SMMEs’ strategic decision-making on new technology adoption

ABSTRACT

The complex nature of small business operations has led to adopting IT as a tool to enhance the productivity, efficiency and growth of Small, Medium and Micro Enterprise (SMMEs). Despite the increased spend on IT, many SMMEs do not understand the importance of IT investment evaluation, which adversely impacts their technology and decision-making ability to realise benefits. The study explores the role evaluation plays in SMMEs’ decision-making to adopt the technology, and the ability to evaluate technology potentials thereof. Case studies were conducted, data collected analysed using the thematic analysis, with hermeneutics employed to derive deeper and richer meanings from the findings. SMMEs often base their decision to adopt the technology on speculative and empirical knowledge from personal judgement, communication preferences and individual experiences. Implications of TE potential may lead to the adoption of inappropriate or non-adoption of the technology, with adverse effects on business sustainability.     

Agile Stage-Gate Management (ASGM) for physical products

We present a qualitative study of Agile Stage-Gate Management (ASGM),: a hybrid new product development methodology that combines Agile and Stage-Gate Management (SGM) approaches for the coordination of new product development. When applied to software projects, Agile is expected to deliver reduced development times, improved resource utilization, and greater financial success. We examine whether ASGM practitioners realize similar outcomes in a sample of global firms developing complex electro-mechanical products (e.g., automobile components, railway propulsion systems, and medical devices). Our grounded theory approach articulates an understanding of ASGM through extensive interviews of experienced professionals. Our thematic analysis supports many expected benefits (i.e., speed to market, innovation enabling), but also does not encourage others, and reveals new pitfalls that deserve recognition (i.e., resource inefficiency). ASGM is not a panacea for all product development. Overall, physical product firms adopting this method can expect reduced development times and higher levels of innovation but will expend more resources to complete development projects, but a dichotomy exists. Physical product developers using ASGM experience a negative impact on project resource efficiency due to the need for dedicated resources, frequent product demonstrations, and duplicative management structures.