Full versus quasi MLE for ARMA-GARCH models with infinitely divisible innovations

We compare the backtesting performance of ARMA-GARCH models with the most common types of infinitely divisible innovations, fit with both full maximum likelihood estimation (MLE) and quasi maximum likelihood estimation (QMLE). The innovation types considered are the Gaussian, Student’s t, α-stable, classical tempered stable (CTS), normal tempered stable (NTS) and generalized hyperbolic (GH) distributions. In calm periods of decreasing volatility, MLE and QMLE produce near identical performance in forecasting value-at-risk (VaR) and conditional value-at-risk (CVaR). In more volatile periods, QMLE can actually produce superior performance for CTS, NTS and α-stable innovations. While the t-ARMA-GARCH model has the fewest number of VaR violations, rejections by the Kupeic and Berkowitz tests suggest excessively large forecasted losses. The α-stable, CTS and NTS innovations compare favourably, with the latter two also allowing for option pricing under a single market model.     

Potential user factors driving adoption of IPTV. What are customers expecting from IPTV?

Internet Protocol Television (IPTV), the convergence services of television and Internet, is being rapidly developed around the world. The advent of digital technologies has changed the convergence market dramatically with the wide diffusion of the convergent services. Using the Technology Acceptance Model as a conceptual framework and method of logistic regression, this research analyzes the demand for IPTV by drawing data from 452 consumers. Individuals' responses to questions about whether they accept IPTV are collected and combined with observations of their socio-economic status and intrinsic/extrinsic factors modified from the Technology Acceptance Model. Results of logistic regression show two variables (intrinsic and extrinsic factors) that seem to explain what influences consumer behavior towards adopting IPTV. Overall, the logistic regression model explains over 50% of the variance in the IPTV adoption. The variances shed light on the multi-open platform environment that IPTV will forge.     

Income inequality and economic growth

Despite the extensive existing literature on income inequality and economic growth, there remains considerable disagreement on the effect of inequality on economic growth. Existing literatures find either a positive or a negative relationship. In this paper, we attempt to theoretically examine that relationship with a stochastic optimal growth model. We make the disagreement clear within a single model. We conclude (i) that both are possible – that is, higher inequality can retard growth in the early stage of economic development, and can encourage growth in a near steady state, (ii) that income redistribution by high income tax does not always reduce income inequality. Income inequality can be reduced by higher income tax in a near steady state, but it cannot be reduced in the early stage of economic development, and (iii) that two government polices – rapid economic growth and low income inequality – can be achieved by low income tax in the early stage of economic development, but both cannot be achieved simultaneously in a near steady state.     

Urban Sensing by Crowdsourcing: Analysing Urban Trip behaviour in Zurich

The research on which this essay is based sought to provide a deeper understanding of live urban activities. The main idea was to obtain in‐depth trip information by integrating sensing technology with crowdsourcing‐based methods. Location and acceleration sensors embedded in smartphones can deliver useful trip information. Research had previously been conducted to find an accurate data analysis algorithm for high‐level data mining, an efficient sensing method for power saving. As a proof of concept, this essay presents a case study of Zurich that successfully implemented previous research achievements in the real environment. It established that urban travel behaviour can, in fact, be collected by sensors embedded in mobile devices, and that the data thus obtained can be used to measure the characteristics of trip behaviour in cities by means of an advanced classifying algorithm and analysis. The strength of this research is its pioneering role in clearing the ground for future urban data collection methods and planning strategies. Specifically, this study could provide answers to the following key questions: How can crowdsourcing be applied to the collection of urban transportation data? What kinds of information can be extracted from the crowdsourced mobile sensing platform? What kinds of knowledge, within the transportation domain, can be derived from the above?     

Liquidity and Twin Crises

This paper proposes a simple analytical framework for understanding 'twin crises'– i.e. crises where a currency crisis and banking crisis occur simultaneously and reinforce each other. The distinguishing feature of such crises is the spill‐over effects across financial institutions through collateral constraints, declines in market values of assets, currency mismatches on the balance sheet and the endogenous amplification of financial distress through asset sales. We explore the role of liquidity and the role of monetary policy in such crises. In particular, a central question is whether raising interest rates in the face of a twin crisis is the appropriate policy response. Raising interest rates has two countervailing effects. Holding the domestic currency becomes more attractive (other things being equal), but the value of the domestic banking system falls due to the fall in asset prices. When assets are marked to market, there is a potential for endogenously generated financial distress that leads to a collapse of asset prices, as well as the exchange rate. It is thus possible that raising interest rates can have the perverse effect of exacerbating both the currency crisis and the banking crisis.     

The rationality and efficacy of decisions under uncertainty and the value of an experiment

Summary A decision maker faces a known prior distribution over payoff relevant states. We compare the expected utility of this individual under two scenarios. In the first, the decision maker makes a choice without further information. In the second, the decision maker has access to an experiment before choosing an action. However, the decision maker does not know the true joint distribution over states and messages. The value of the experiment as measured by the difference in the two utility levels can be negative as well as positive. We give a condition which is necessary and sufficient for the experiment to be valuable in our sense, for any decision problem.An earlier version of this paper was circulated under the title Noisy Bayes Updating and the Value of Information. We have gained from the comments of Stephen Coate, John Geanakoplos, Larry Samuelson, Timothy Van Zandt and seminar participants at Harvard Business School, Princeton, Boston University, the international conference on game theory at Stony Brook 1992 and the Winter meeting of the Econometric Society at Anaheim 1993. The first author received support for this project from NSF grant #SES-9308515 and a University of Pennsylvania Research Foundation Grant.     

Impacts of household loan regulation on financial stability: evidence from Korea

The paper examines whether banking regulations and monetary policy contributed to controlling the fragility of household debt in Korea. The results show that housing loan regulations such as debt to income regulation contributed to a lower household debt delinquency ratio. Lowering the target interest rate provided additional stabilisation of the delinquency ratio. It is recommended that the government adopt an appropriate mix of regulation and monetary policy to control household financial fragility. The financial supervisory services need to be involved in managing debt to income regulation and minimising financial instability and financial market distortions. Further, the monetary authority has to adopt a more effective position in controlling the real lending interest rate and the delinquency ratio of household loans. Such a policy mix will improve effectiveness in controlling financial fragility, especially at a time of financial crisis.     

Efficiency of the Banking Industry Structure in Korea*

This paper analyzes whether the efficiency of the Korean banking industry has improved since the bank restructuring in 1997, and whether a bank with high efficiency has a larger market share. This paper uses an efficient structure hypothesis model to examine the relationship between the banks' efficiencies and their profitability. The data envelopment analysis method is applied to measure the efficiency and profitability of the banking industry in order to minimize possible bias due to the inflow of public funds for the bank consolidation. The two‐step Heckman selection method is used to correct for survivorship bias in the model. The derived result indicates that banks with higher efficiencies tend to record higher profit. Moreover, higher pure technological efficiency and scale efficiency have a positive effect on a bank's market share and concentration.     

Risk management with interdependent choice

Risks faced by traders from price movements are sometimes magnifiedby the actions of other traders. Risk-management systems whichneglect this feature may give a seriously misleading pictureof the true risks. The hazards arising from this potential blindspotare at their most dangerous when the prevailing conventionalwisdom lulls traders into a false sense of security on the attractivenessof a trading position. The efforts of one trader to reversehis trade makes more acute the need to follow suit on the partof others. For markets dominated by traders with short timehorizons, such interdependence leads to exaggerated price movements.Estimates of 'value at risk' which recognize such interdependenceof actions can diverge substantially from those given by conventionaltechniques.