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...

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...

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...

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).

Pricing and hedging of long-term interest rate sensitive products require to extrapolate the term structure beyond observable maturities. For the resulting limiting term structure we show two results by postulating no arbitrage in a bond market with infinitely increasing maturities: long...

Turbo-Certificates are one of the most popular structured equity products for private investors in Germany. They can be regarded as special forms of barrier options. The relation between the barrier level and the strike price is especially important for the design of these products. By using a...

The fluctuation of stock prices is modelled as a sequence of temporary equilibria on a financial market with different types of agents. We summarize joint work with M. Schweizer on the class of Ornstein-Uhlenbeck processes in a random environment which appears in the diffusion limit. Moreover,...