@inbook{65310,
abstract = {{Trust between client and consultant is perhaps the most important asset in con-sulting, as this is a highly intangible knowledge-intensive business that concerns is-sues of outstanding strategic and operational importance for the customers. Cli-ents who have not worked with a particular consultancy face considerable risk when they place an order while lacking reliable information about the service quality they can expect. There is a strong link between trust and reputation, as the positive reputation of a consultancy can act as a substitute for a new client’s missing individual experience with the provider, fostering trust in the service quali-ty. Thus, creating, maintaining, and demonstrating a good reputation is of signifi-cant importance for consultancies in a very competitive industry.
To facilitate trustworthy signals, we design and implement a novel reputation mechanism that carries a monetary weight stored on a blockchain network as an immutable, decentralized, and transparent ledger. Based on an implementation in the Ethereum network and subsequent evaluation, we conclude that the reputation mechanism can contribute to leveling information asymmetry and reducing risk while increasing reputation and trust. The mechanism lends itself to being used in other business-to-business scenarios that suffer from similar information asymmetries.}},
author = {{Hemmrich, Simon and Nissen, Volker}},
booktitle = {{ Advanced Studies in Consulting Research and Digitalization – A Scientific Update on the Digital Transformation of the Consulting Industry. Springer.}},
editor = {{Nissen, Volker}},
keywords = {{Reputation Systems, Consulting, Design Science Invention, Incentive, Blockchain, Monetary ratings, building trust, reduce information asymmetry consulting, B2B reputation system, consulting risk reduction, supplier evaluation system}},
title = {{{A blockchain-based reputation system for consulting}}},
year = {{2026}},
}
@techreport{49873,
abstract = {{This study analyzes the impact of tax complexity on the location of tax employees and tax risk. Using a hand-collected dataset of more than 7,500 tax employees from 348 European-listed multinationals, we identify two types of firm-level costs associated with tax complexity—tax employees, and tax risk. We find that firms locate more tax employees in countries with greater tax complexity. This association is particularly pronounced for complexity in tax procedures. We also find that multinationals operating in countries with high tax complexity are associated with higher tax risk. The incremental tax risk vanishes for firms that locate more tax employees in countries with highly complex tax procedures, while we find no risk reduction from additional tax employees in countries with complex tax rules. Our results reveal that multinationals eliminate 25 percent of overall tax complexity-related tax risk through targeted location of tax employees.}},
author = {{Giese, Henning and Koch, Reinald and Sureth-Sloane, Caren}},
keywords = {{tax complexity, tax complexity cost, tax department, tax employees, tax risk}},
title = {{{Where to Locate Tax Employees? The Role of Tax Complexity and Tax Risk Implications}}},
doi = {{10.2139/ssrn.4888151}},
year = {{2024}},
}
@article{48063,
abstract = {{Brainwaves have demonstrated to be unique enough across individuals to be useful as biometrics. They also provide promising advantages over traditional means of authentication, such as resistance to external observability, revocability, and intrinsic liveness detection. However, most of the research so far has been conducted with expensive, bulky, medical-grade helmets, which offer limited applicability for everyday usage. With the aim to bring brainwave authentication and its benefits closer to real world deployment, we investigate brain biometrics with consumer devices. We conduct a comprehensive measurement experiment and user study that compare five authentication tasks on a user sample up to 10 times larger than those from previous studies, introducing three novel techniques based on cognitive semantic processing. Furthermore, we apply our analysis on high-quality open brainwave data obtained with a medical-grade headset, to assess the differences. We investigate both the performance, security, and usability of the different options and use this evidence to elicit design and research recommendations. Our results show that it is possible to achieve Equal Error Rates as low as 7.2% (a reduction between 68–72% with respect to existing approaches) based on brain responses to images with current inexpensive technology. We show that the common practice of testing authentication systems only with known attacker data is unrealistic and may lead to overly optimistic evaluations. With regard to adoption, users call for simpler devices, faster authentication, and better privacy.
}},
author = {{Arias-Cabarcos, Patricia and Fallahi, Matin and Habrich, Thilo and Schulze, Karen and Becker, Christian and Strufe, Thorsten}},
issn = {{2471-2566}},
journal = {{ACM Transactions on Privacy and Security}},
keywords = {{Safety, Risk, Reliability and Quality, General Computer Science}},
number = {{3}},
pages = {{1--36}},
publisher = {{Association for Computing Machinery (ACM)}},
title = {{{Performance and Usability Evaluation of Brainwave Authentication Techniques with Consumer Devices}}},
doi = {{10.1145/3579356}},
volume = {{26}},
year = {{2023}},
}
@article{48058,
author = {{Winkel, Fabian and Deuse-Kleinsteuber, Johannes and Böcker, Joachim}},
issn = {{0018-9529}},
journal = {{IEEE Transactions on Reliability}},
keywords = {{Electrical and Electronic Engineering, Safety, Risk, Reliability and Quality}},
pages = {{1--14}},
publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}},
title = {{{Run-to-Failure Relay Dataset for Predictive Maintenance Research With Machine Learning}}},
doi = {{10.1109/tr.2023.3255786}},
year = {{2023}},
}
@article{49309,
abstract = {{I study the effect of heterogeneous beliefs about asset prices on the long-term behavior of financial markets. Starting from the ideas of Abreu and Brunnermeier (Citation2003), a two-dimensional system of differential equations is developed. The first dynamic variable is the asset price growth rate. The second dynamic variable is the number of investors who believe that asset prices are abnormally high. In a phase plane analysis, I find both stable and unstable equilibria, depending on the spread of information and the response to other agents’ beliefs. If individuals try to increase their returns while perceiving more overpricing, these equilibria can be spirals or even approach limit cycles. Although I intend to study general price patterns, abnormally high asset prices can be caused by financial bubbles. In this model, bubbles can emerge and deflate both in cycles or directly, or they can grow until they burst. Further, I analyze market behavior after a central bank increases the interest rate. This can lead to new stable equilibria, but the emergence and bursting of bubbles cannot be prevented.}},
author = {{Burs, Carina}},
issn = {{2332-2039}},
journal = {{Cogent Economics & Finance}},
keywords = {{asset pricing, subjective information, stability conditions, monetary policy, risk aversion}},
number = {{2}},
publisher = {{Informa UK Limited}},
title = {{{A model of cycles and bubbles under heterogeneous beliefs in financial markets}}},
doi = {{10.1080/23322039.2023.2272485}},
volume = {{11}},
year = {{2023}},
}
@inproceedings{49785,
abstract = {{Reputation is indispensable for online business since it supports customers in their buying decisions and
allows sellers to justify premium prices. While IS research has investigated reputation systems mainly
as review systems on online platforms for business-to-consumer (B2C) transactions, no proper solutions
have been developed for business-to-business (B2B) transactions yet. We use blockchain technology to
propose a new class of reputation systems that apply ratings as voluntary bonus payments: Before a
transaction is performed, customers commit to pay a bonus that is granted if a service provider has
performed a service properly. As opposed to rival reputation systems that build on cumulated ratings
or reviews, our system enables monetized reputation mechanisms that are inextricably linked with online
transactions. We expect this system class to provide more trustworthy ratings, which might reduce
agency costs and serve quality providers to establish a reputation towards new customers, building on
second-order trust.}},
author = {{Hemmrich, Simon}},
booktitle = {{Proceedings of 31st European Conference on Information Systems (ECIS 2023)}},
keywords = {{Trust, Risk, Reputation System, Blockchain Technology, Business Reputation System.}},
location = {{Kristiansand}},
title = {{{Business Reputation Systems based on Blockchain Technology—A Risky Advance}}},
year = {{2023}},
}
@article{31844,
abstract = {{Encrypting data before sending it to the cloud ensures data confidentiality but requires the cloud to compute on encrypted data. Trusted execution environments, such as Intel SGX enclaves, promise to provide a secure environment in which data can be decrypted and then processed. However, vulnerabilities in the executed program give attackers ample opportunities to execute arbitrary code inside the enclave. This code can modify the dataflow of the program and leak secrets via SGX side channels. Fully homomorphic encryption would be an alternative to compute on encrypted data without data leaks. However, due to its high computational complexity, its applicability to general-purpose computing remains limited. Researchers have made several proposals for transforming programs to perform encrypted computations on less powerful encryption schemes. Yet current approaches do not support programs making control-flow decisions based on encrypted data.
We introduce the concept of
dataflow authentication
(DFAuth) to enable such programs. DFAuth prevents an adversary from arbitrarily deviating from the dataflow of a program. Our technique hence offers protections against the side-channel attacks described previously. We implemented two flavors of DFAuth, a Java bytecode-to-bytecode compiler, and an SGX enclave running a small and program-independent trusted code base. We applied DFAuth to a neural network performing machine learning on sensitive medical data and a smart charging scheduler for electric vehicles. Our transformation yields a neural network with encrypted weights, which can be evaluated on encrypted inputs in
\( 12.55 \,\mathrm{m}\mathrm{s} \)
. Our protected scheduler is capable of updating the encrypted charging plan in approximately 1.06 seconds.
}},
author = {{Fischer, Andreas and Fuhry, Benny and Kußmaul, Jörn and Janneck, Jonas and Kerschbaum, Florian and Bodden, Eric}},
issn = {{2471-2566}},
journal = {{ACM Transactions on Privacy and Security}},
keywords = {{Safety, Risk, Reliability and Quality, General Computer Science}},
number = {{3}},
pages = {{1--36}},
publisher = {{Association for Computing Machinery (ACM)}},
title = {{{Computation on Encrypted Data Using Dataflow Authentication}}},
doi = {{10.1145/3513005}},
volume = {{25}},
year = {{2022}},
}
@article{35992,
abstract = {{In this paper new semiparametric generalized autoregressive conditional heteroscedasticity (GARCH) models with long memory are introduced. A multiplicative decomposition of the volatility into a conditional component and an unconditional component is assumed. The estimation of the latter is carried out by means of a data-driven local polynomial smoother. According to the revised recommendations by the Basel Committee on Banking Supervision to measure market risk in the banks’ trading books, these new semiparametric GARCH models are applied to obtain rolling one-step ahead forecasts for the value-at-risk and expected shortfall (ES) for market risk assets. Standard regulatory traffic-light tests and a newly introduced traffic-light test for the ES are carried out for all models. In addition, model performance is assessed via a recently introduced model selection criterion. The practical relevance of our proposal is demonstrated by a comparative study. Our results indicate that semiparametric long-memory GARCH models are a meaningful substitute for their conventional, parametric counterparts. }},
author = {{Letmathe, Sebastian and Feng, Yuanhua and Uhde, André}},
journal = {{Journal of Risk}},
keywords = {{long memory, generalized autoregressive conditional heteroscedasticity (GARCH) models, value-at-risk (VaR), expected shortfall (ES), traffic-light test, backtesting}},
number = {{2}},
title = {{{Semiparametric GARCH models with long memory applied to Value at Risk and Expected Shortfall}}},
volume = {{25}},
year = {{2022}},
}
@article{29317,
abstract = {{In this paper new semiparametric GARCH models with long memory are in- troduced. The estimation of the nonparametric scale function is carried out by an adapted version of the SEMIFAR algorithm (Beran et al., 2002). Recurring on the revised recommendations by the Basel Committee to measure market risk in the banks' trading books (Basel Committee on Banking Supervision, 2013), the semi- parametric GARCH models are applied to obtain rolling one-step ahead forecasts for the Value at Risk (VaR) and Expected Shortfall (ES) for market risk assets. In addition, standard regulatory traffic light tests (Basel Committee on Banking Supervision, 1996) and a newly introduced traffic light test for the ES are carried out for all models. The practical relevance of our proposal is demonstrated by a comparative study. Our results indicate that semiparametric long memory GARCH models are an attractive alternative to their conventional, parametric counterparts.}},
author = {{Letmathe, Sebastian and Feng, Yuanhua and Uhde, André}},
journal = {{Journal of Risk}},
keywords = {{Semiparametric, long memory, GARCH models, forecasting, Value at Risk, Expected Shortfall, traffic light test, Basel Committee on Banking Supervision}},
title = {{{Semiparametric GARCH models with long memory applied to Value at Risk and Expected Shortfall}}},
doi = {{10.21314/JOR.2022.044}},
year = {{2022}},
}
@article{5163,
abstract = {{Employing a unique hand-collected sample of 956 credit risk securitization transactions issued by 64 stock-listed
European banks across the EU-13 plus Switzerland over the period from 1997 to 2010, this paper empirically analyzes
the impact of securitization on the issuing banks’ effective tax rates. Our analysis reveals that banks may reduce their
tax expense through securitization via a direct and indirect channel suggesting that tax avoidance may be a further
motive for banks to engage in the securitization business. These baseline findings remain robust under various
robustness checks, especially when implementing structural equation models and controlling for a reverse causality
between the banks’ tax burden and their incentive to securitize. Finally, various sensitivity analyses provide further
important results and implications for tax policies, banking regulation and the ongoing process of revitalizing the
European securitization market.}},
author = {{Uhde, André}},
journal = {{The Quarterly Review of Economics and Finance}},
keywords = {{Securitization, Credit risk transfer, Effective tax rates, European banking}},
pages = {{411--421}},
title = {{{Tax avoidance through securitization}}},
doi = {{10.1016/j.qref.2020.07.008}},
volume = {{79}},
year = {{2021}},
}
@techreport{36060,
abstract = {{Merging a sample of 492 merger and acquisition (M&A) announcements from 284 acquiring firms across Europe and North America with data from 5-year single-name credit default swaps (CDSs) written on stock-listed acquiring firms between 2005 and 2018, the paper at hand empirically analyzes the CDS investors’ risk perceptions of M&A announcements using event study methodologies. As a baseline result, we provide evidence for significantly positive cumulative average abnormal CDS spread changes for both, European and North American acquirers suggesting that CDS investors perceive an increase in the acquiring firms’ credit risk exposures due to M&A announcements. Our baseline finding holds under several robustness checks, especially when controlling for the robustness of the empirical design. Moreover, results from a large variety of sensitivity analyses reveal a number of deal and firm characteristics that may explain why CDS investors from our sample expect an increase in the acquirers’ credit risk exposures due to forthcoming M&A transactions. }},
author = {{Hippert, Benjamin and Uhde, André}},
keywords = {{credit default swaps, risk perception of CDS investors, mergers and acquisitions, event study}},
title = {{{CDS Investors’ Risk Perceptions of M&A Announcements}}},
year = {{2021}},
}
@techreport{29316,
abstract = {{Employing a unique and hand-collected dataset of securitization transactions by European banks, this paper analyzes the relationship between true sale loan securitization and the issuing banks’ non-performing loans to total assets ratios (NPLRs). We provide evidence for an NPLR-reducing effect during the boom phase of securitizations suggesting that banks (partly) securitized NPLs as the most risky junior tranche. In contrast, we find the reverse effect during the crises period indicating that issuing banks demonstrated `skin in the game'. A variety of sensitivity analyses provides further important implications for the vital debate on reducing NPL exposures and regulating securitization markets.}},
author = {{Hippert, Benjamin and Uhde, André and Wengerek, Sascha Tobias}},
keywords = {{European Banking, Non-performing Loans, Risk Allocation, Securitization}},
title = {{{Risk allocation through securitization - Evidence from non-performing loans}}},
year = {{2021}},
}
@techreport{37136,
abstract = {{This study examines the relation between voluntary audit and the cost of debt in private firms. We use a sample of 4,058 small private firms operating in the period 2006‐2017 that are not subject to mandatory audits. Firms decide for a voluntary audit of financial statements either because the economic setting in which they operate effectively forces them to do so (e.g., ownership complexity, export‐oriented supply chain, subsidiary status) or because firm fundamentals and/or financial reporting practices limit their access to financial debt, both reflected in earnings quality. We use these factors to model the decision for voluntary audit. In the outcome analyses, we find robust evidence that voluntary audits are associated with higher, rather than lower, interest rate by up to 3.0 percentage points. This effect is present regardless of the perceived audit quality (Big‐4 vs. non‐Big‐4), but is stronger for non‐Big‐4 audits where auditees have a stronger position relative to auditors. Audited firms’ earnings are less informative about future operating performance relative to unaudited counterparts. We conclude that voluntary audits facilitate access to financial debt for firms with higher risk that may otherwise have no access to this form of financing. The price paid is reflected in higher interest rates charged to firms with voluntary audits – firms with higher information and/or fundamental risk.}},
author = {{Ichev, Riste and Koren, Jernej and Kosi, Urska and Sitar Sustar, Katarina and Valentincic, Aljosa}},
keywords = {{private firms, voluntary audit, cost of debt, self‐selection bias, risk}},
title = {{{Cost of Debt for Private Firms Revisited: Voluntary Audits as a Reflection of Risk}}},
year = {{2021}},
}
@article{17522,
abstract = {{Employing a unique hand-collected sample of 956 credit risk securitization transactions issued by 64 stock-listed European banks across the EU-13 plus Switzerland over the period from 1997 to 2010, this paper empirically analyzes the impact of securitization on the issuing banks’ effective tax rates. Our analysis reveals that banks may reduce their tax expense through securitization via a direct and indirect channel suggesting that tax avoidance may be a further motive for banks to engage in the securitization business. These baseline findings remain robust under various robustness checks, especially when implementing structural equation models and controlling for a reverse causality between the banks’ tax burden and their incentive to securitize. Finally, various sensitivity analyses provide further important results and implications for tax policies, banking regulation and the ongoing process of revitalizing the European securitization market.}},
author = {{Uhde, André}},
issn = {{1062-9769}},
journal = {{The Quarterly Review of Economics and Finance}},
keywords = {{Securitization, Credit risk transfer, Effective tax rates, European banking}},
title = {{{Tax avoidance through securitization}}},
doi = {{10.1016/j.qref.2020.07.008}},
year = {{2020}},
}
@article{17401,
abstract = {{Employing a unique hand-collected sample of 956 credit risk securitization transactions issued by 64 stock-listed European banks across the EU-13 plus Switzerland over the period from 1997 to 2010, this paper empirically analyzes the impact of securitization on the issuing banks’ effective tax rates. Our analysis reveals that banks may reduce their tax expense through securitization via a direct and indirect channel suggesting that tax avoidance may be a further motive for banks to engage in the securitization business. These baseline findings remain robust under various robustness checks, especially when implementing structural equation models and controlling for a reverse causality between the banks’ tax burden and their incentive to securitize. Finally, various sensitivity analyses provide further important results and implications for tax policies, banking regulation and the ongoing process of revitalizing the European securitization market.}},
author = {{Uhde, André}},
journal = {{The Quarterly Review of Economics and Finance}},
keywords = {{Securitization, credit risk transfer, effective tax rates, European banking}},
title = {{{Tax avoidance through securitization}}},
year = {{2020}},
}
@techreport{46541,
abstract = {{Theoretical papers show that optimal prevention decisions in the sense of selfprotection (i.e., primary prevention) depend not only on the level of (second-order) risk aversion but also on higher-order risk preferences such as prudence (third-order risk aversion). We study empirically whether these theoretical results hold and whether prudent individuals show less preventive (self-protection) effort than non-prudent individuals. We use a unique dataset that combines data on higher-order risk preferences and various measures of observed real-world prevention behavior. We find that prudent individuals indeed invest less in self-protection as measured by influenza vaccination. This result is driven by high risk individuals such as individuals >60 years of age or chronically ill. We do not find a clear empirical relationship between riskpreferences and prevention in the sense of self-insurance (i.e. secondary prevention). Neither risk aversion nor prudence is related to cancer screenings such as mammograms, Pap smears or X-rays of the lung.}},
author = {{Mayrhofer, Thomas and Schmitz, Hendrik}},
keywords = {{prudence, risk preferences, prevention, vaccination, screening}},
publisher = {{RWI - Leibniz-Institut für Wirtschaftsforschung, Ruhr-University Bochum, TU Dortmund University, University of Duisburg-Essen}},
title = {{{Prudence and prevention: Empirical evidence}}},
volume = {{863}},
year = {{2020}},
}
@techreport{13146,
abstract = {{Employing a sample of 492 merger and acquisition (M&A) announcements from 284 acquirers across North America and Europe between 2005 and 2018, this study analyzes the impact of M&A announcements on an acquirers abnormal CDS spread changes. We find that spreads from CDS which are written on acquirers increase by 310 bps during a symmetric five-day event window suggesting that investors expect an increase in the acquirers credit risk exposure due to M&As. Next to this baseline finding, we conduct a large variety of sensitivity analyses to gain more insight into the driving factors of the rising risk perception of CDS investors due to M&A announcements.}},
author = {{Hippert, Benjamin}},
keywords = {{credit default swaps, risk perception of CDS investors, mergers and acquisitions, event study}},
title = {{{The relationship between announcements of complete mergers and acquisitions and acquirers' abnormal CDS spread changes}}},
year = {{2019}},
}
@article{10279,
abstract = {{Are cryptocurrency traders driven by a desire to invest in a new asset class to diversify their portfolio or are they merely seeking to increase their levels of risk? To answer this question, we use individual-level brokerage data and study their behavior in stock trading around the time they engage in their first cryptocurrency trade. We find that when engaging in cryptocurrency trading investors simultaneously increase their risk-seeking behavior in stock trading as they increase their trading intensity and use of leverage. The increase in risk-seeking in stocks is particularly pronounced when volatility in cryptocurrency returns is low, suggesting that their overall behavior is driven by excitement-seeking. }},
author = {{Pelster, Matthias and Breitmayer, Bastian and Hasso, Tim}},
issn = {{0165-1765}},
journal = {{Economics Letters}},
keywords = {{cryptocurrencies, bitcoin, investor, risk-seeking}},
pages = {{98--100}},
title = {{{Are cryptocurrency traders pioneers or just risk-seekers? evidence from brokerage accounts}}},
doi = {{10.1016/j.econlet.2019.06.013}},
volume = {{182}},
year = {{2019}},
}
@article{4562,
abstract = {{Employing main and sector-specific investment-grade CDS indices from the North American and European CDS market and performing mean-variance out-of-sample analyses for conservative and aggressive investors over the period from 2006 to 2014, this paper analyzes portfolio benefits of adding corporate CDS indices to a traditional financial portfolio consisting of stock and sovereign bond indices. As a baseline result, we initially find an increase in portfolio (downside) risk-diversification when adding CDS indices, which is observed irrespective of both CDS markets, investor-types and different sub-periods, including the global financial crisis and European sovereign debt crisis. In addition, the analysis reveals higher portfolio excess returns and performance in CDS index portfolios, however, these effects clearly differ between markets, investor-types and sub-periods. Overall, portfolio benefits of adding CDS indices mainly result from the fact that institutional investors replace sovereign bond indices rather than stock indices by CDS indices due to better risk-return characteristics. Our baseline findings remain robust under a variety of robustness checks. Results from sensitivity analyses provide further important implications for institutional investors with a strategic focus on a long-term conservative portfolio management.}},
author = {{Hippert, Benjamin and Uhde, André and Wengerek, Sascha Tobias}},
journal = {{Review of Derivatives Research }},
keywords = {{Corporate credit default swap indices, Mean-variance asset allocation, Out-of-sample portfolio optimization, Portfolio risk-diversification, Portfolio performance evaluation}},
number = {{2}},
pages = {{203--259}},
title = {{{Portfolio Benefits of Adding Corporate Credit Default Swap Indices: Evidence from North America and Europe}}},
doi = {{https://doi.org/10.1007/s11147-018-9148-8}},
volume = {{22}},
year = {{2019}},
}
@techreport{15392,
abstract = {{Employing a sample of 492 merger and acquisition (M&A) announcements from
284 acquirers across North America and Europe between 2005 and 2018, this study
analyzes the impact of M&A announcements on an acquirers abnormal CDS spread
changes. We nd that spreads from CDS which are written on acquirers increase
by 310 bps during a symmetric ve-day event window suggesting that investors
expect an increase in the acquirers credit risk exposure due to M&As. Next to
this baseline nding, we conduct a large variety of sensitivity analyses to gain more
insight into the driving factors of the rising risk perception of CDS investors due to
M&A announcements.}},
author = {{Uhde, André and Hippert, Benjamin}},
keywords = {{credit default swaps, risk perception of CDS investors, mergers and acquisitions, event study}},
title = {{{The relationship between announcements of complete mergers and acquisitions and acquirers' abnormal CDS-Spread changes}}},
year = {{2019}},
}