Too Connected to Fail? Inferring Network Ties from Price Co-movements
Jakob Bosma, Michael Koetter, Michael Wedow
Journal of Business and Economic Statistics,
Nr. 1,
2019
Abstract
We use extreme value theory methods to infer conventionally unobservable connections between financial institutions from joint extreme movements in credit default swap spreads and equity returns. Estimated pairwise co-crash probabilities identify significant connections among up to 186 financial institutions prior to the crisis of 2007/2008. Financial institutions that were very central prior to the crisis were more likely to be bailed out during the crisis or receive the status of systemically important institutions. This result remains intact also after controlling for indicators of too-big-to-fail concerns, systemic, systematic, and idiosyncratic risks. Both credit default swap (CDS)-based and equity-based connections are significant predictors of bailouts. Supplementary materials for this article are available online.
Artikel Lesen
The Importance of Estimation Uncertainty in a Multi-Rating Class Loan Portfolio
Henry Dannenberg
IWH Discussion Papers,
Nr. 11,
2011
Abstract
This article seeks to make an assessment of estimation uncertainty in a multi-rating class loan portfolio. Relationships are established between estimation uncertainty and parameters such as probability of default, intra- and inter-rating class correlation, degree of inhomogeneity, number of rating classes used, number of debtors and number of historical periods used for parameter estimations. In addition, by using an exemplary portfolio based on Moody’s ratings, it becomes clear that estimation uncertainty does indeed have an effect on interest rates.
Artikel Lesen
Berücksichtigung von Schätzunsicherheit bei der Kreditrisikobewertung: Vergleich des Value at Risk der Verlustverteilung des Kreditrisikos bei Verwendung von Bootstrapping und einem asymptotischen Ansatz
Henry Dannenberg
IWH Discussion Papers,
Nr. 3,
2009
Abstract
Bei der Kreditrisikobewertung müssen die Parameter Ausfallwahrscheinlichkeit und
-korrelation geschätzt werden. Diese Schätzung erfolgt unter Unsicherheit. In der Literatur werden asymptotische Konfidenzregionen diskutiert, um diese Unsicherheit bei der simultanen Schätzung beider Parameter zu bewerten. Diese Regionen setzen allerdings eine sehr lange Datenhistorie für eine genaue Bewertung voraus. Als Alternative bietet sich bei kurzen Datenhistorien Bootstrapping an. Diese Methode ist allerdings deutlich rechenintensiver. Im vorliegenden Beitrag wird untersucht, ab welcher Anzahl historisch verfügbarer Perioden Bootstrapping und eine Wald-Konfidenzregion zu einer vergleichbaren Bewertung des Kreditrisikos gelangen. Die hier genutzten Methoden führen zu ähnlichen Ergebnissen, wenn über 100 historische Perioden zur Verfügung stehen.
Artikel Lesen
Economies of Scope in European Railways: An Efficiency Analysis
Christian Growitsch, Heike Wetzel
IWH Discussion Papers,
Nr. 5,
2006
Abstract
In the course of railway reforms in the end of the last century, national European governments, as well the EU Commission, decided to open markets and to separate railway networks from train operations. Vertically integrated railway companies – companies owning a network and providing transport services – argue that such a separation of infrastructure and operations would diminish the advantages of vertical integration and would therefore not be suitable to raise economic welfare. In this paper, we conduct a pan-European analysis to investigate the performance of European railways with a particular focus on economies of vertical integration. We test the hypothesis that integrated railways realise economies of joint production and, thus, produce railway services on a higher level of efficiency. To determine whether joint or separate production is more efficient we apply a Data Envelopment Analysis super-efficiency bootstrapping model which relates the efficiency for integrated production to a virtual reference set consisting of the separated production technology. Our findings are that in a majority of European Railway companies exist economies of scope.
Artikel Lesen
