A Factor-model Approach for Correlation Scenarios and Correlation Stress Testing
Natalie Packham, Fabian Wöbbeking
Journal of Banking and Finance,
April
2019
Abstract
In 2012, JPMorgan accumulated a USD 6.2 billion loss on a credit derivatives portfolio, the so-called “London Whale”, partly as a consequence of de-correlations of non-perfectly correlated positions that were supposed to hedge each other. Motivated by this case, we devise a factor model for correlations that allows for scenario-based stress testing of correlations. We derive a number of analytical results related to a portfolio of homogeneous assets. Using the concept of Mahalanobis distance, we show how to identify adverse scenarios of correlation risk. In addition, we demonstrate how correlation and volatility stress tests can be combined. As an example, we apply the factor-model approach to the “London Whale” portfolio and determine the value-at-risk impact from correlation changes. Since our findings are particularly relevant for large portfolios, where even small correlation changes can have a large impact, a further application would be to stress test portfolios of central counterparties, which are of systemically relevant size.
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Innovation Cooperation in East and West Germany: A Study on the Regional and Technological Impact
Uwe Cantner, Alexander Giebler, Jutta Günther, Maria Kristalova, Andreas Meder
International Journal of Computational Economics and Econometrics,
3/4
2018
Abstract
In this paper, we investigate the impact of regional and technological innovation systems on innovation cooperation. We develop an indicator applicable to regions, which demonstrates the relative regional impact on innovation cooperation. Applying this method to German patent data, we find that regional differences in the degree of innovation cooperation do not only depend on the technology structure of a region but also on specific regional effects. High-tech oriented regions, whether east or west, are not automatically highly cooperative regions. East German regions have experienced a dynamic development of innovation cooperation since re-unification in 1990. Their cooperation intensity remains higher than in West German regions.
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IWH-Präsident: Silicon Valley Bank in Deutschland?
Reint E. Gropp
Einzelveröffentlichungen,
2023
Abstract
Nach dem Zusammenbruch der zahlungsunfähigen US-amerikanischen Silicon Valley Bank zieht Reint Gropp, Präsident des Leibniz-Instituts für Wirtschaftsforschung Halle (IWH), drei Lehren für die europäische Bankenaufsicht.
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The Impact of Government Procurement Composition on Private R&D Activities
Viktor Slavtchev, Simon Wiederhold
Abstract
This paper addresses the question of whether government procurement can work as a de facto innovation policy tool. We develop an endogenous growth model with quality-improving in-novation that incorporates industries with heterogeneous innovation sizes. Government demand in high-tech industries increases the market size in these industries and, with it, the incentives for private firms to invest in R&D. At the economy-wide level, the additional R&D induced in high-tech industries outweighs the R&D foregone in all remaining industries. The implications of the model are empirically tested using a unique data set that includes federal procurement in U.S. states. We find evidence that a shift in the composition of government purchases toward high-tech industries indeed stimulates privately funded company R&D.
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Aktuelle Trends: Wirtschaftswachstum und sinkende CO2-Emissionen schließen sich nicht aus
Reint E. Gropp
Wirtschaft im Wandel,
Nr. 1,
2023
Abstract
Erneuerbare Energiequellen und energiesparender technischer Fortschritt ermöglichen es, den CO2-Ausstoß einer Volkswirtschaft bei steigendem Bruttoinlandsprodukt zu senken. Um die Klimaziele zu erreichen, müssen diese Anstrengungen aber noch deutlich verstärkt werden
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Aggregate Dynamics with Sectoral Price Stickiness Heterogeneity and Aggregate Real Shocks
Alessandro Flamini, Iftekhar Hasan
Journal of Money, Credit and Banking,
im Erscheinen
Abstract
This paper investigates the relationship between heterogeneity in sectoral price stickiness and the response of the economy to aggregate real shocks. We show that sectoral heterogeneity reduces inflation persistence for a constant average duration of price spells, and that inflation persistence can fall despite duration increases associated with increases in heterogeneity. We also find that sectoral heterogeneity reduces the persistence and volatility of interest rate and output gap for a constant price spells duration, while the qualitative impact on inflation volatility tends to be positive. A relevant policy implication is that neglecting price stickiness heterogeneity can impair the economic dynamics assessment.
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Uncovering Disaggregated Oil Market Dynamics: A Full-Information Approach to Granular Instrumental Variables
Christiane Baumeister, James D. Hamilton
Working Paper,
2023
Abstract
The world price of oil is determined by the interactions of multiple producers and consumers who face different constraints and shocks. We show how this feature of the oil market can be used to estimate local and global elasticities of supply and demand and provide a rich set of testable restrictions. We develop a novel approach to estimation based on full-information maximum likelihood that generalizes the insights from granular instrumental variables. We conclude that the supply responses of Saudi Arabia and adjustments of inventories have historically played a key role in stabilizing the price of oil. We illustrate how our structural model can be used to analyze how individual producers and consumers would dynamically adapt to a geopolitical event such as a major disruption in the supply of oil from Russia.
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Risky Oil: It's All in the Tails
Christiane Baumeister, Florian Huber, Massimiliano Marcellino
NBER Working Paper,
Nr. 32524,
2024
Abstract
The substantial fluctuations in oil prices in the wake of the COVID-19 pandemic and the Russian invasion of Ukraine have highlighted the importance of tail events in the global market for crude oil which call for careful risk assessment. In this paper we focus on forecasting tail risks in the oil market by setting up a general empirical framework that allows for flexible predictive distributions of oil prices that can depart from normality. This model, based on Bayesian additive regression trees, remains agnostic on the functional form of the conditional mean relations and assumes that the shocks are driven by a stochastic volatility model. We show that our nonparametric approach improves in terms of tail forecasts upon three competing models: quantile regressions commonly used for studying tail events, the Bayesian VAR with stochastic volatility, and the simple random walk. We illustrate the practical relevance of our new approach by tracking the evolution of predictive densities during three recent economic and geopolitical crisis episodes, by developing consumer and producer distress indices that signal the build-up of upside and downside price risk, and by conducting a risk scenario analysis for 2024.
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Non-Standard Errors
Albert J. Menkveld, Anna Dreber, Felix Holzmeister, Juergen Huber, Magnus Johannesson, Markus Kirchner, Sebastian Neusüss, Michael Razen, Utz Weitzel, et al.
Abstract
In statistics, samples are drawn from a population in a datagenerating process (DGP). Standard errors measure the uncertainty in sample estimates of population parameters. In science, evidence is generated to test hypotheses in an evidencegenerating process (EGP). We claim that EGP variation across researchers adds uncertainty: non-standard errors. To study them, we let 164 teams test six hypotheses on the same sample. We find that non-standard errors are sizeable, on par with standard errors. Their size (i) co-varies only weakly with team merits, reproducibility, or peer rating, (ii) declines significantly after peer-feedback, and (iii) is underestimated by participants.
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