Additive and Multiplicative Uncertainty Revisited: What Explains the Contrasting Biases?

above the certainty level while for additive uncertainty the price should be lower than the certainty level. This note gives an intuitive explanation for the result after first presenting a parsimonious review of the two models. We also discuss which, if either, of the two models is more realistic. Received December 14, 2001; revised version received July 16, 2002 Published online: April 30, 2003 We thank referees for helpful comments. Ciaran Driver would like to acknowledge the research facilities from ANU, Canberra for their help in writing this paper.     

Market Liquidity and Trading Activity

Previous studies of liquidity span short time periods and focus on the individual security. In contrast, we study aggregate market spreads, depths, and trading activity for U.S. equities over an extended time sample. Daily changes in market averages of liquidity and trading activity are highly volatile and negatively serially dependent. Liquidity plummets significantly in down markets. Recent market volatility induces a decrease in trading activity and spreads. There are strong day-of-the-week effects; Fridays accompany a significant decrease in trading activity and liquidity, while Tuesdays display the opposite pattern. Long- and short-term interest rates influence liquidity. Depth and trading activity increase just prior to major macroeconomic announcements.     

Pricing Options on an Asset with Bernoulli Jump-Diffusion Returns

The price movements of certain assets can be modeled by stochastic processes that combine continuous diffusion with discrete jumps. This paper compares values of options on assets with no jumps, jumps of fixed size, and jumps drawn from a lognormal distribution. It is shown that not only the magnitude but also the direction of the mispricing of the Black-Scholes model relative to jump models can vary with the distribution family of the jump component. This paper also discusses a methodology for the numerical valuation, via a backward induction algorithm, of American options on a jump-diffusion asset whose early exercise may be profitable. These cannot, in general, be accurately priced using analytic models. The procedure has the further advantage of being easily adaptable to nonanalytic, empirical distributions of period returns and to nonstationarity in the underlying diffusion process.     

The effects of mergers on price and output: Two case studies from the airline industry

The literature on industrial organization contains very little direct evidence on the effects of actual mergers. This study estimates the effects of two recent airline mergers approved by the Department of Transportation over the objection of the Department of Justice. The merger of TWA and Ozark appears to have caused a slight increase in fares and a far greater reduction in service on city pairs out of St Louis. The merger of Northwest and Republic appears to have caused a significant increase in fares and a significant reduction in overall service on city pairs out of Minneapolis-St Paul.     

iTV: A major opportunity for financial services,or not?

Interactive television has arrived, thanks to substantial technology investments that have been made by Sky and others. It is growing in importance as innovative interactive applications are developed for broadcast programmes (eg the BBCi service and Big Brother), and for advertising — and will develop further when broadband deployment gets to critical mass. Readers should not expect a television-variant of the world wide web, however. This was tried during 2000–2002 in the form of web look-alike, interactive ‘walled garden’ sites, and failed to attract critical mass footfall. The model has evolved and now revolves around interactive content synchronised with broadcast, which offers financial services companies an interesting new way to increase awareness and to differentiate the service presentation. Furthermore, over the next ten years, broadband is expected to usher in a new era of personalised television — in which specialised broadcasts (such as personal pensions advice programmes) can be made available on demand. The observations in this paper are mainly drawn from the UK, where digital television penetration is high; the lessons can be applied more broadly, however, and are relevant to any organisation thinking of promoting its service through entertainment channels.     

Theological ethics and business ethics

Philosophers have constituted business ethics as a field by providing a systematic overview that interrelates its problems and concepts and that supplies the basis for building on attained results. Is there a properly theological task in business ethics? The religious/theological literature on business ethics falls into four classes: (1) the application of religious morality to business practices; (2) the use of encyclical teachings about capitalism; (3) the interpretation of business relations in agapa-istic terms; and (4) the critique of business from a liberation theological point of view. Theologians have not adequately addressed the questions of whether there are particular theological tasks in the field as they define it, and whether, if they define it, the theological definition is different from the philosophical.     

Global economy gathering strength

Encouraged by a highly expansionary economic policy, the global economy is enjoying a rapid upturn. Utilisation of capacity is high in many sectors, particularly in the growth centres of the USA and East Asia, where China leads the field. With inflationary risks on the increase, most countries are now shifting the focus of economic policy. Fiscal policy in particular can be expected to provide little in the way of further stimulus. In addition, there has been a turnaround in interest rates in many countries. Yet how quickly can the monetary reins be tightened without jeopardising growth or endangering price stability?     

New ways of achieving debt sustainability beyond the enhanced HIPC Initiative

In 1996 the Heavily Indebted Poor Countries (HIPC) Initiative was launched by the Bretton Woods institutions to reduce the external debt burden of low-income countries (LICs) to sustainable levels in a reasonably short period of time because debt constitutes an obstacle to sustainable economic growth and poverty reduction. In some HIPCs, however, debt sustainability has been in danger despite debt relief under the HIPC Initiative. Debt relief is a necessary but not a sufficient condition for development. It can do no more than play a catalytic role. The question, then, is how to achieve debt sustainability beyond the HIPC Initiative.