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Correlation Scenarios and Correlation Stress Testing
Natalie Packham, Fabian Wöbbeking
Journal of Economic Behavior and Organization,
January
2023
Abstract
We develop a general approach for stress testing correlations of financial asset portfolios. The correlation matrix of asset returns is specified in a parametric form, where correlations are represented as a function of risk factors, such as country and industry factors. A sparse factor structure linking assets and risk factors is built using Bayesian variable selection methods. Regular calibration yields a joint distribution of economically meaningful stress scenarios of the factors. As such, the method also lends itself as a reverse stress testing framework: using the Mahalanobis distance or Highest Density Regions (HDR) on the joint risk factor distribution allows to infer worst-case correlation scenarios. We give examples of stress tests on a large portfolio of European and North American stocks.
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Structural Interpretation of Vector Autoregressions with Incomplete Identification: Revisiting the Role of Oil Supply and Demand Shocks
Christiane Baumeister, James D. Hamilton
American Economic Review,
No. 5,
2019
Abstract
Traditional approaches to structural vector autoregressions (VARs) can be viewed as special cases of Bayesian inference arising from very strong prior beliefs. These methods can be generalized with a less restrictive formulation that incorporates uncertainty about the identifying assumptions themselves. We use this approach to revisit the importance of shocks to oil supply and demand. Supply disruptions turn out to be a bigger factor in historical oil price movements and inventory accumulation a smaller factor than implied by earlier estimates. Supply shocks lead to a reduction in global economic activity after a significant lag, whereas shocks to oil demand do not.
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18.12.2018 • 22/2018
IWH leads large scale EU research project on productivity
Is productivity growth slowing in industrialised countries? And if so, why? From the start of 2019, the Halle Institute for Economic Research (IWH) will be addressing these questions as the coordinator of a new EU project. Economists and statistics experts from nine European partners will collaborate on the three-year project, entitled MICROPROD. With a total budget of just under three million euros, it is the IWH’s largest EU project to date.
Steffen Müller
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13.12.2018 • 21/2018
Economic activity in the world and in Germany is losing momentum
In the second half of 2018, the upturn of the German economy has stalled. Production of the automotive industry declined because of delays in switching production to WLTP compliant cars. Irrespectively of this, the German export business has been weakening since the beginning of the year, since the global economy, burdened by the political uncertainties surrounding trade conflicts, the impending Brexit and the conflict over the Italian budget, was unable to keep up with the high momentum of 2017. “It is to be expected that the less benign external environment will not only dampen exports, but will also impact on companies’ investment and hiring decisions”, says Oliver Holtemöller, head of the Department Macroeconomics and vice president at Halle Institute for Economic Research (IWH). Gross domestic product is expected to increase by 1.5% in 2018 and by 1.4% in 2019, which is roughly equal to the growth rate of economic capacity in Germany.
Oliver Holtemöller
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Inference in Structural Vector Autoregressions when the Identifying Assumptions are not Fully Believed: Re-evaluating the Role of Monetary Policy in Economic Fluctuations
Christiane Baumeister, James D. Hamilton
Journal of Monetary Economics,
2018
Abstract
Point estimates and error bands for SVARs that are set identified are only justified if the researcher is persuaded that some parameter values are a priori more plausible than others. When such prior information exists, traditional approaches can be generalized to allow for doubts about the identifying assumptions. We use information about both structural coefficients and impacts of shocks and propose a new asymmetric t-distribution for incorporating information about signs in a nondogmatic way. We apply these methods to a three-variable macroeconomic model and conclude that monetary policy shocks are not the major driver of output, inflation, or interest rates.
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Tail-risk Protection Trading Strategies
Natalie Packham, Jochen Papenbrock, Peter Schwendner, Fabian Wöbbeking
Quantitative Finance,
No. 5,
2017
Abstract
Starting from well-known empirical stylized facts of financial time series, we develop dynamic portfolio protection trading strategies based on econometric methods. As a criterion for riskiness, we consider the evolution of the value-at-risk spread from a GARCH model with normal innovations relative to a GARCH model with generalized innovations. These generalized innovations may for example follow a Student t, a generalized hyperbolic, an alpha-stable or a Generalized Pareto distribution (GPD). Our results indicate that the GPD distribution provides the strongest signals for avoiding tail risks. This is not surprising as the GPD distribution arises as a limit of tail behaviour in extreme value theory and therefore is especially suited to deal with tail risks. Out-of-sample backtests on 11 years of DAX futures data, indicate that the dynamic tail-risk protection strategy effectively reduces the tail risk while outperforming traditional portfolio protection strategies. The results are further validated by calculating the statistical significance of the results obtained using bootstrap methods. A number of robustness tests including application to other assets further underline the effectiveness of the strategy. Finally, by empirically testing for second-order stochastic dominance, we find that risk averse investors would be willing to pay a positive premium to move from a static buy-and-hold investment in the DAX future to the tail-risk protection strategy.
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Should We Trust in Leading Indicators? Evidence from the Recent Recession
Katja Drechsel, Rolf Scheufele
Abstract
The paper analyzes leading indicators for GDP and industrial production in Germany. We focus on the performance of single and pooled leading indicators during the pre-crisis and crisis period using various weighting schemes. Pairwise and joint significant tests are used to evaluate single indicator as well as forecast combination methods. In addition, we use an end-of-sample instability test to investigate the stability of forecasting models during the recent financial crisis. We find in general that only a small number of single indicator models were performing well before the crisis. Pooling can substantially increase the reliability of leading indicator forecasts. During the crisis the relative performance of many leading indicator models increased. At short horizons, survey indicators perform best, while at longer horizons financial indicators, such as term spreads and risk spreads, improve relative to the benchmark.
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Keeping the Bubble Alive! The Effects of Urban Renewal and Demolition Subsidies in the East German Housing Market
Dominik Weiß
IWH Discussion Papers,
No. 11,
2009
Abstract
German urban renewal programs are favoring the cities in the Eastern part since the re-unification in 1990. This was accompanied additionally by attractive tax incentives, designed as an accelerated declining balance method of depreciation for housing investments during the late 1990s. The accumulated needs for comfortable housing after 40 years of a disastrous housing policy of the GDR era were generally accepted as justification for the subvention policy. But various subsidies and tax incentives caused a construction boom, false allocations, and a price bubble in Eastern Germany. After recognizing that the expansion of housing supply was not in line with the demographic development and that high vacancy rates were jeopardizing housing companies and their financial backers, policy changed in 2001. Up to now, the government provides demolition grants to reduce the vast oversupply. By means of a real option approach, it is ex-plained how different available forms of subsidies and economic incentives for landlords lift real estate values. The option value representing growth expectations and opportunities is calculated as an observable market value less an estimated fundamental value. Empirical results disclose higher option premiums for cities in Eastern Germany and a strong correlation of the option premium with urban renewal spending.
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