Research


Research Focus: Financial Stability and Digital Currencies

Bastien’s research explores how digital currencies and financial innovation are transforming financial systems. His work focuses on the implications of central bank digital currencies (CBDCs), stablecoins, and cryptocurrencies for financial stability, market functioning, and regulation. Combining finance with data-driven methods, he studies how these new forms of money interact with traditional financial institutions and risk channels.

  1. Financial Stability and Digital Currencies: He examines how CBDCs, stablecoins, and crypto-assets influence liquidity, financial intermediation, and systemic risk, with particular attention to the links between digital asset markets and the broader financial system.
  2. Crypto-asset Markets and Investment: His research studies pricing, risk, and investor behavior in cryptocurrency markets, and the role digital assets can play in portfolio allocation and risk management.
  3. Asset Pricing and High-Frequency Data: He uses high-frequency and alternative data to better understand return dynamics and short-term predictors, particularly in fast-moving digital asset markets.

Overall, his research aims to better understand how digital currencies are reshaping monetary and financial systems, and to provide insights that are relevant for both policymakers and market participants.


Publications

A Cleaning Framework for Cryptocurrency Data: Toward Investable Cryptocurrency Universes, Journal of Alternative Investments, forthcoming 2026 (with J.-M. Maeso and V. Milhau)
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We develop a reproducible three-step protocol to clean daily cryptocurrency data from CoinMarketCap (CMC), one of the most used data providers in academic research. The procedure targets three recurring anomalies that distort market-level indicators: (i) extreme market-cap spikes, (ii) one-day and multi-day dips in Bitcoin dominance, and (iii) abnormal trading volumes. Using more than 28,000 cryptocurrencies from 2014–2024, we show that the method modifies only a small subset of data while improving the reliability of key market indicators. We do not adjust prices or returns, preserving actual trading conditions. As an application, we construct dynamic investable universes using cleaned data and realistic constraints based on market capitalization and volume. This exercise shows that cleaning and filtering jointly produce more reliable universes, reducing spurious extremes and making them suitable for empirical asset pricing research and portfolio construction.


Do risk preferences drive momentum in cryptocurrencies?, Finance Research Letters, 73, 106531, 2025 (with J. Proelss and D. Schweizer).
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The cryptocurrency market operates continuously, leading to frequent price fluctuations and information dissemination. This can hinder investors from reacting promptly to market changes, a phenomenon attributed to investors' limited attention. Research in traditional markets shows that the limited attention bias allows successful implementation of momentum strategies. However, past research on cryptocurrency markets finds mixed results. To resolve the puzzle, we utilize a survivorship bias-free dataset while accounting for variations in market capitalization and trading volume. This differentiation is crucial given young and tech affine retail investors' inclination toward smaller-capitalized cryptocurrencies, due to their higher risk tolerance and limited attention. More risk averse investors such as institutional investors, in contrast, focus more on top cryptocurrencies. In line with expectations, we find effective momentum strategies among larger-capitalized cryptocurrencies.


Research Papers

Clustered Network Connectedness: A New Measurement Framework, with Application to Global Equity Markets, mimeo, February 2025 (with F.X. Diebold and K. Yilmaz).

Network connections, both across and within markets, are central in countless economic contexts. In recent decades, a large literature has developed and applied flexible methods for measuring network connectedness and its evolution, based on variance decompositions from vector autoregressions (VARs), as in Diebold and Yilmaz (2014). Those VARs are, however, typically identified using full orthogonalization (Sims, 1980), or no orthogonalization (Koop, Pesaran, and Potter, 1996; Pesaran and Shin, 1998), which, although useful, are special and extreme cases of a more general framework that we develop in this paper. In particular, we allow network nodes to be connected in "clusters", such as asset classes, industries, regions, etc., where shocks are orthogonal across clusters (Sims style orthogonalized identification) but correlated within clusters (Koop-Pesaran-Potter-Shin style generalized identification), so that the ordering of network nodes is relevant across clusters but irrelevant within clusters. After developing the clustered connectedness framework, we apply it in a detailed empirical exploration of sixteen country equity markets spanning three global regions.


Asymmetries at the core of short-term return predictability, mimeo, January 2025 (with J. Breckenfelder and R. Tédongap).

We propose a novel approach to improve short-term equity return predictability by analyzing truncated high-frequency return distributions. We segment returns into core and tail components, focusing on core and tail asymmetries — differences between `typical' or `extreme' upside and downside variances. Our empirical findings show that these predictors achieve an in-sample adjusted R^2 of about 7% and an out-of-sample R^2 exceeding 3% for one-month-ahead market return forecasts, outperforming traditional predictors such as valuation ratios and the variance risk premium. It is the core asymmetry, rather than the tail asymmetry that drives the predictive power.


Decrypting Crypto-assets: Introduction to an Emerging Asset Class, mimeo, August 2024

Crypto-assets constitute a large and heterogenous asset class. Only a minority of crypto-assets qualify as crypto-currencies, while the large majority provide services that go beyond Bitcoin’s peer-to-peer payment system pioneered by Nakamoto (2008). This paper introduces a comprehensive taxonomy spanning crypto-currencies, service crypto-assets, smart-contract platforms, distributed applications and tokenized assets (including both fungible and non-fungible tokens). To illustrate stylized facts and capture various risks of the cross-section of crypto-assets this paper relies on a novel dataset covering more than 14,000 crypto-assets.


Is Bitcoin Fragility Systematically Related to Global Uncertainty ?, mimeo, January 2026 (with M. Chiabane and G.Giménez Roche)
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We propose a novel measure of Bitcoin fragility based on the asymmetric behavior of extreme returns within a parametric jump-diffusion framework. Fragility is defined as the relative dominance of crash-driven over boom-driven tail risk and admits a direct economic interpretation in terms of the existence of moments of gross and inverted returns. Unlike event-based approaches that focus on identifying individual jumps or decomposing realized volatility, our framework treats jumps as structural components shaping tail behavior and emphasizes moment dominance rather than jump timing or transmission. Using daily Bitcoin returns from 2013 to 2024 and rolling-window estimation, we document substantial time variation in fragility and examine its association with global uncertainty and volatility indicators. The empirical analysis is deliberately reduced-form and does not aim at causal identification or forecasting. We find that economic policy uncertainty is positively associated with Bitcoin fragility, while equity market volatility is negatively associated. These relationships operate primarily through changes in jump intensities rather than jump probabilities, indicating that macro-financial uncertainty affects the severity of extreme outcomes more than their frequency. Overall, our results characterize Bitcoin as a fragile speculative asset whose downside tail dominance varies systematically with global financial conditions, highlighting a distinct dimension of tail risk complementary to existing volatility- and dependence-based measures.



Conferences, Seminars and Panels

2025 Junior Worskshop, Society for Nonlinear Dynamics and Econometrics
MacroFor Seminar Series, International Institute of Forecasting
Finance Seminar Series, Zayed University, Dubaï, UAE
WG Risk Seminar Series, ESSEC Business Scholl, Paris, France
2024 International Conference in Banking and Financial Studies, Catania, Italy
Cryptocurrency Research Conference, Dubaï, UAE
International Symposium of Forecasting, Dijon, France
Forecasting Financial Markets, Rennes, France
2023 Finance Seminar, SKEMA Business School, Paris, France
Cryptocurrency Research Conference, Monaco, Monaco
Digital, Innovation, Financing and Entrepreneurship Conference, Montreal, Canada
Forecasting Financial Markets, University of Rennes, Rennes, France
Cross Country Perspectives in Finance Conference, Paphos, Cyprus*
2022 Finance Seminar, Concordia University, Montreal, Canada
Panelist at Décryptons les cryptos, FrenchTec, Montreal, Canada
Cardiff FinTech Conference, Cardiff University, Cardiff, UK
Future of Finance, Suzhou University, Suzhou, China
FinTech Workshop, Inseec Research Center, Lyon, France
2021 Panelist at Cryptocurrency and Fund Performance, CAIA, Geneva, Switzerland
2020 Finance Seminar, NEOMA Business School, Paris, France
Finance Seminar, Boston University, Boston, USA
2019 Paris December Finance Meeting, Paris, France
Finance Seminar, ESSEC Business School, Paris, France
Finance Seminar, Bank of Canada, Ottawa, Canada
CEMA Annual Meeting, Carnegie Mellon University, Pittsburgh, USA
Asset and Risk Management, Amundi, Paris, France
Finance PhD Workshop, Université Paris-Dauphine, Paris, France
Fintech Adoption and Economic Behavior, EM Strasbourg, Strasbourg, France
2018 Finance Seminar, ESSEC Business Scholl, Paris, France
Computational and Financial Econometrics, University of Pisa, Pisa, Italy
FinTech and Crypto-Finance, NEOMA Business School, Paris, France

* presented by a coauthor