How Often to Sample a Continuous-Time Process in the Presence of Market Microstructure Noise

In theory, the sum of squares of log returns sampled at highfrequency estimates their variance. When market microstructurenoise is present but unaccounted for, however, we show thatthe optimal sampling frequency is finite and derives its closed-formexpression. But even with optimal sampling, using say 5-minreturns when transactions are recorded every second, a vastamount of data is discarded, in contradiction to basic statisticalprinciples. We demonstrate that modeling the noise and usingall the data is a better solution, even if one misspecifiesthe noise distribution. So the answer is: sample as often aspossible.     

A HPC based cloud model for real-time energy optimisation

Recent research has emphasised that an increasing number of enterprises need computation environments for executing HPC (High Performance Computing) applications. Rather than paying the cost of ownership and possess physical, fixed capacity clusters, enterprises can reserve or rent resources for undertaking the required tasks. With the emergence of new computation paradigms such as cloud computing it has become possible to solve a wider range of problems due to their capability to handle and process massive amounts of data. On the other hand, given the pressing regulatory requirement to reduce the carbon footprint of our built environment, significant researching efforts have been recently directed towards simulation-based building energy optimisation with the overall objective of reducing energy consumption. Energy optimisation in buildings represents a class of problems that requires significant computation resources and generally is a time consuming process especially when undertaken with building simulation software, such as EnergyPlus. In this paper we present how a HPC based cloud model can be efficiently used for running and deploying EnergyPlus simulation-based optimisation in order to fulfil a number of objectives related to energy consumption. We describe and evaluate the establishment of such an application-based environment, and consider a cost perspective to determine the efficiency over several cases we explore. This study identifies the following contributions: (i) a comprehensive examination of issues relevant to the HPC community, including performance, cost, user perspectives and range of user activities, (ii) a comparison of two different execution environments such as HTCondor and CometCloud and determine their effectiveness in supporting simulation-based optimisation and (iii) a detailed performance analysis to locate the limiting factors of these execution environments.     

Maximum likelihood estimation of stochastic volatility models

We develop and implement a method for maximum likelihood estimation in closed-form of stochastic volatility models. Using Monte Carlo simulations, we compare a full likelihood procedure, where an option price is inverted into the unobservable volatility state, to an approximate likelihood procedure where the volatility state is replaced by proxies based on the implied volatility of a short-dated at-the-money option. The approximation results in a small loss of accuracy relative to the standard errors due to sampling noise. We apply this method to market prices of index options for several stochastic volatility models, and compare the characteristics of the estimated models. The evidence for a general CEV model, which nests both the affine Heston model and a GARCH model, suggests that the elasticity of variance of volatility lies between that assumed by the two nested models.     

Political Connections and Leverage: Firm‐level Evidence from Pakistan

This study investigates the impact of political connections on corporate financing decisions using a sample of listed Pakistani firms over the period 2002–2010. We find a positive and significant link between long‐term debt and political connections, which reflects greater access to credit. Such preferential treatment escalates with the strength of the connected politician. Furthermore, positive effects of political connections are seen to be stronger for large firms and those affiliated with business groups. Copyright © 2014 John Wiley & Sons, Ltd.     

Theoretical motives of corporate cash holdings and political connections: firms level evidence from a developing economy

In this paper, we revisit the theoretical motives of corporate cash holdings while concentrating on the effect of political connections. In particular, we postulate two competing hypotheses for the effects that political connections can have on cash holdings: ‘substitution effect hypothesis’ and ‘complementary effect hypothesis’. Using the data on Pakistani firms over the period 2002–2010, we find that connected firms hold significantly larger cash reserves than their non-connected counterparts, thus confirming the ‘complementary hypothesis’, which suggests that agency problems lead connected firms to accumulate large amount of cash. Further, this effect is found to be more pronounced in dictatorial as opposed to democratic regimes indicating the presence of higher degrees of political patronage in that period. Finally, we also find differences in the complementary effect based on firm characteristics. Our results suggest that the firm size and leverage have increasing effects on the cash holdings of connected firms, contrary to the mainstream literature standpoint.     

An empirical investigation of asset pricing models under divergent lending and borrowing rates

Asset pricing theory implies that the estimate of the zero-beta rate should fall between divergent lending and borrowing rates. This paper proposes a formal test of this restriction using the difference between the prime loan rate and the 1-month Treasury bill rate as a proxy for the difference between borrowing and lending rates. Based on simulations, this paper shows that in the ordinary least squares case, the Fama and MacBeth (J Pol Econ 81:607–636, 1973) t-statistic has high power against a general alternative, which is not true of the Shanken (Rev Financ Stud 5:1–33, 1992) and Kan et al. (J Financ doi:10.1111/jofi.12035, 2013) t-statistics. In the generalized least squares case, all three t-statistics have high power. The empirical investigation highlights that only the intertemporal capital asset pricing model reasonably prices the zero-beta portfolio. Other models, such as the Fama and French (J Financ Econ 33:3–56, 1993) model, do not assign the correct value to the zero-beta rate.     

Inventory inaccuracies in the wholesale supply chain

The inventory level shown in the Information System contrary to popular belief and assumptions in most academic papers and in spite of the considerable amounts invested in information technology, is often inaccurate. The inventory inaccuracy occurs when the inventory shown in the Information System is not in agreement with the actually available inventory. In this paper, we first describe the major factors generating inventory inaccuracy. Then, we provide situations permitting to manage an inventory system subject to errors. We provide a general framework permitting to model the inventory inaccuracy issue. In particular, we link the inaccuracy issue with the well known random yield problem. The shown link permits us to derive the optimal ordering policy of an inventory framework where demand satisfaction is done based on the inventory records (which are subject to inaccuracies). We also propose an analysis permitting to show the added value of an advanced identification system such as the RFID technology.     

Corporate cash holdings and dividend payments: evidence from simultaneous analysis

This study explores the simultaneous relationship between corporate cash holdings and dividend policy using a large sample of around 400 non‐financial firms for the period from 1991 to 2008. The results show that cash holdings are affected by dividends, leverage, growth, size, risk, profitability, and working capital ratio. Dividend policy is affected by cash, leverage, growth, size, risk, and profit. When controlling for simultaneity, dividend payments do not appear to significantly affect cash holdings, nor do cash holdings affect dividend policy. The empirical analysis suggests that simultaneity is crucial in analyzing corporate cash holdings and dividend policy. Copyright © 2011 John Wiley & Sons, Ltd.     

CEO chairman controversy: evidence from the post financial crisis period

Review of Quantitative Finance and Accounting - Regulators generally discourage bank CEOs also holding the role of board Chairman, as this governance structure can hinder independent...     

Political connections and corporate performance: Evidence from Pakistan

This study seeks to understand how political connections affect firm performance. Using a hand‐collected dataset of Pakistani firms from 2008–2014, our firm fixed effects and Heckman two‐stage regression results show that connected firms outperform those without political ties. Moreover, we show channels through which political benefits are realized in terms of greater access to debt, lower financing costs and lower tax rates. These benefits are found to be particularly large when firms are connected to politicians who held political positions most recently and firms connected through their owners. Finally, we do not find evidence for differences in political favours across regulated and unregulated industries.