I do research in empirical corporate finance, corporate governance, sustainable finance, and machine learning.
I am a recipient of the 2021 Lamfalussy Research Fellowship from the European Central Bank (ECB) as well as a Research Affiliate at the Centre for Economic Policy Research (CEPR). I have also received the 2022 Rising Star Award from the International Corporate Governance Network (ICGN).
I worked as an Assistant Professor of Finance at the Frankfurt School of Finance & Management from August 2020 to July 2022 and in August 2022, I joined the University of Bern. Since 2022, I have been a Visiting Professor at the Frankfurt School of Finance & Management.
Invited expert to the European Commission (DG FISMA) on ESG ratings, contributing to Regulation (EU) 2024/3005 on the transparency and integrity of ESG rating activities.
with Rüdiger Fahlenbrach, René M. Stulz, and Jérôme Taillard
Journal of Financial Economics, Vol. 140, Issue 3, pp. 699–725, 2021
Using more than 50,000 firm-years from 1988 to 2015, we show that the empirical relation between a firm’s Tobin’s q and managerial ownership is systematically negative. When we restrict our sample to larger firms as in the prior literature, our findings are consistent with the literature, showing that there is an increasing and concave relation between q and managerial ownership. We show that these seemingly contradictory results are explained by cumulative past performance and liquidity. Better performing firms have more liquid equity, which enables insiders to more easily sell shares after the IPO, and they also have a higher Tobin’s q.
The explosion in ESG research has led to a strong reliance on ESG rating providers. We document widespread changes to the historical ratings of a key rating provider, Refinitiv ESG (formerly ASSET4). Depending on whether the original or rewritten data are used, ESG-based classifications of firms into ESG quantiles and tests that relate ESG scores to returns change. While there is a positive link between ESG scores and firms’ stock market performance in the rewritten data, we fail to observe such a relationship in the initial data. The ESG data rewriting is an ongoing rather than a one-off phenomenon.
I study the quality of the governance pillar of environmental, social, and corporate governance (ESG) ratings. Since 2018, ESG integration strategies, many of which rely on ESG ratings, have dominated the ESG investing sphere. I examine the governance ratings’ ability to provide useful information to shareholders. My results not only suggest rather limited success in predicting relevant firm outcomes (such as financial-statement restatements, governance incidents, class action lawsuits, operating performance, firm value, stock returns, and credit ratings), but in the case of most raters, I identify multiple instances of counterintuitive results, that is, with the opposite direction of the effect.
Selected talks
Finance Research Seminar, University of Bern (December 2024)
Asia-Pacific Corporate Finance Online Workshop (ACFOW, March 2025)
Sustainable Finance Brown-Bag Seminar, University of Hamburg (March 2025)
Grant: Slovak National Bank · €20,000Featured: ICGN Policy Newsletter (March 2026)
We investigate whether individuals correctly interpret corporate sustainability disclosures using a pre-registered survey experiment. We provide novel evidence that individuals can meaningfully differentiate emissions of firms along a greenness scale, even though their assessments exhibit a central tendency bias. This leads to overestimation of greenness among browner firms and underestimation among greener firms, with the bias disproportionately stronger for greener firms. We observe this bias even among finance professionals and sustainability experts. As a result, firms' financial incentives to invest in emissions reductions may be attenuated. However, we also demonstrate that some disclosure design features improve individuals' differentiation ability.
This paper presents the first large-scale empirical analysis of the pledging phenomenon among U.S. CEOs. Between 2007 and 2016, 7.6% of publicly listed U.S. firms disclosed that their CEOs had pledged company stock as collateral for a loan. On average, CEOs pledge 38% of their shares. The mean loan value is an economically sizeable $65 million. CEOs use the funds to either double down (6.0%), hedge their ownership (3.5%), or to obtain liquidity while maintaining ownership (90.5%). My event study results reveal that stock market participants view pledging as value-enhancing, but perceive significant pledging as value-destroying. Similarly, I find no evidence of its negative shareholder value consequences, except for CEOs who engage in significant pledging.
This paper provides the first systematic evidence on the incidence, magnitude, and consequences of margin-call-induced sales by U.S. CEOs. Using a comprehensive hand-collected sample of CEOs who pledge company stock as collateral, I identify margin-call sales following stock price declines and study their implications for CEO incentives and firm policies. I find that 14.8% of pledging CEOs experience margin-call sales, reducing CEO ownership by 31.2% on average and 22.0% at the median. Yet 87.8% of firms do not restrict pledging afterward, and compensation contracts change little. I find no evidence of reduced investment; founder CEOs increase R&D following margin calls.
with Michael Ryf, Larissa Schäfer and Sascha Steffen
Grant: 2021 Lamfalussy Research Fellowship, ECB · €10,000
A methodology change of an ESG rating provider introduces plausibly exogenous variation in firms’ ESG ratings, which allows us to study their effect on the cost of debt of U.S. firms. We find that loans spreads of downgraded ESG-rated firms in the secondary corporate loan market increase by about 10% compared to non-downgraded ESG-rated firms and compared to before the rating downgrade. ESG rating downgrades do not increase fundamental default risk of the firm but the premium charged by lenders above the spread for default risk. We find that the effect is stronger for firms that are more financially constrained and firms that are more exposed to ESG and, particularly, climate risk concerns. Importantly, we find that also loan spreads of private (unrated) firms in industries especially affected by ESG rating downgrades increased after the methodology change.
In 2020, ESG integration surpassed exclusionary screening-based strategies and became the largest sustainable investment strategy globally. Despite their numerous flaws, ESG ratings continue to shape the investment process. We therefore provide an overview of the most common issues that researchers and practitioners should be aware of when working with ESG ratings. The issues we identify pertain to ISS ESG, MSCI ESG, Sustainalytics ESG, S&P ESG, and Refinitiv ESG ratings, among others.
See Presentations for a comprehensive list of talks.
Teaching
Teaching
My teaching focuses on AI and machine learning, risk management, ESG and sustainable finance, and corporate finance, combining analytical rigor with real-world applications to equip students with practical, future-oriented skills.
Data Analytics and Machine Learning in Finance
Frankfurt School of Finance & Management · since 2021
Course lecturerMasterEnglish
This course is aimed at students who would like to apply machine learning (ML) to real-life problems in finance. It covers both the theoretical and the practical aspects of the most common ML algorithms, and shows how to critically evaluate different models and select the most suitable one. Applications include sentiment analysis, text parsing, and credit default prediction, as well as creating structured data from unstructured data and accessing data sets via API.
ESG Investing and Sustainable Finance
University of Bern · 2022–2026
Course lecturerBachelorEnglish
This course is aimed at students who would like to learn more about the world of environmental, social and governance (ESG) investing and sustainable finance. It provides an overview of the most relevant aspects of ESG and sustainable investing which are presented in a way that should nurture critical thinking.
Risk Management
University of Bern · 2022–2026
Course lecturerMasterEnglish
This course provides the core knowledge for financial risk managers. It provides a strong foundation for understanding how financial risks are identified, measured, and controlled in today’s complex markets. It covers key themes in risk management, including credit, market, interest rate, and operational risks, as well as the regulation of financial institutions and emerging topics such as ESG.
Managerial Finance
EPFL · 2018–2020
Teaching assistantEMBAEnglish
Course textbook: Corporate Finance by Jonathan B. Berk and Peter DeMarzo.
Introduction to Finance
EPFL · 2016–2020
Teaching assistantMasterEnglish
Course textbook: Corporate Finance by Jonathan B. Berk and Peter DeMarzo.
Grundlagen der Betriebswirtschaftslehre
Fundamentals of Business Administration · LMU · 2011–2012
Teaching assistantBachelorGerman
Course textbook: Einführung in die Betriebswirtschaftslehre by Werner Neus.
Presentations and discussions
Conference and seminar presentations, discussions, and talks delivered
Best Paper Award, 2022 Cornell University ESG Investing Research ConferenceWinner · USD 10,000
2022
Best Paper Award, ECGI 2022 Corporate Governance SymposiumJohn L. Weinberg/IRRCi Research Award, Weinberg Center at the University of Delaware · USD 10,000
2021
Lamfalussy Fellowship, European Central BankEUR 10,000
2015
Swiss Finance Institute PhD Program ScholarshipLéman campus · CHF 30,000
Teaching awards
2019
Best teaching assistant of the Master in Financial Engineering (MFE) sectionGraduating MFE class of 2019
2018
College of Management of Technology (CDM) award for outstanding teaching
Professional awards
2022
Rising Star AwardInternational Corporate Governance Network (ICGN)
2022
Women of the Future: 50 Rising Stars in ESGSelected
Professional certificates
2026
Risk and AI Certificate (RAI)Global Association of Risk Professionals (GARP)
2022
CFA Institute Certificate in ESG InvestingCFA Institute
2019
Chartered Financial Analyst® (CFA)CFA Institute
2013
Professional Risk Manager (PRM™)Professional Risk Managers’ International Association (PRMIA)
