In this paper, we consider the market for video games, where some firms are active in both, the market for video games hardware and software. It is puzzling that hardware can be easily made compatible with duplicated (i.e. pirated) software. We ask, whether there exist strategic reasons...

This note points out the differences between conducting several projects within one big firm (common ownership) and conducting each project within an independent firm (separate ownership).

The Benefit and Cost of Winner Picking: Redistribution Vs Incentives |AB| A multi-divisional firm can engage in "winner-picking" to redistribute scarce funds efficiently across divisions. But there is a conflict between rewarding winners (investing) and producing resources internally to reward...

Within the Internal Ratings-Based (IRB) approach of Basel II it is assumed that idiosyncratic risk has been fully diversi?ed away. The impact of undiversi?ed idiosyncratic risk on portfolio Value-at-Risk can be quanti?ed via a granularity adjustment (GA). We provide an analytic formula for the...

We show that the saddle-point approximation method to quantify the impact of undiversi?ed idiosyncratic risk in a credit portfolio is inappropriate in the presence of double default effects. Speci?cally, we prove that there does not exist an equivalent formula to the granularity adjustment, that...

In 2005 the Internal Ratings Based (IRB) approach of `Basel II' was enhanced by a `treatment of double default effects' to account for credit risk mitigation techniques such as ordinary guarantees or credit derivatives. This paper reveals several severe problems of this approach and presents a...

In the standard CAPM with a riskless asset we prove existence of equilibria without assuming concavity of the investor's utility functions. Moreover, we give a uniqueness result using assumptions on the risk aversion of investors.

This paper proposes a new explanation for the smile and skewness effects in implied volatilities. Starting from a microeconomic equilibrium approach, we develop a diffusion model for stock prices explicitly incorporating the technical demand induced by hedging strategies. This leads to a...

We provide three characterizations of the minimal martingale measure P associated to a given d- dimensional semimartingale X. In each case, P is shown to be the unique solution of an optimization problem where one minimizes a certain functional over a suitable class of signed local martingale...

Easley / Kiefer / O'Hara / Paperman (1996) (EKOP) have proposed an empirical methodology that allows to estimate the probability of informed trading and that has subsequently been used to address a wide range of issues in market microstructure. The data needed for estimation is the number of...