Guillaume Vuillemey

Endogenous Derivative Networks

This paper proposes a network formation model of an OTC derivatives market where both prices and quantities are bilaterally negociated. The key feature of the framework is to endogenize the network of exposures, the gross and net notional amounts traded and the collateral delivered through initial and variation margins, as a function of idiosyncratic counterparty risk and regulatory collateral and clearing requirements. Using the framework, we investigate numerically the size of the derivatives network, the aggregate collateral demand and the pricing of the contracts under the following schemes: (i) various levels of collateralization for uncleared transactions, (ii) rehypothecation of received collateral and (iii) clearing through a central clearing party (CCP). Overall results suggest that dynamic effects due to the endogeneity of the derivative network to the collateralization and clearing requirements have sizeable consequences on both contract volumes and prices. Intermediary trading and market liquidity are reduced by higher collateralization requirements and enhanced by rehypothecation, while the potential for contagion is reduced. Not accounting for dynamic effects in current market conditions may lead to over-estimate collateral demand induced by mandatory central clearing by up to 22%.

Wholesale funding dry-ups

We empirically explore the fragility of wholesale funding of banks, using transaction‐level data on short‐term, unsecured certificates of deposit in the European market. We do not observe a market‐wide freeze during the 2008 to 2014 period. Yet, many banks suddenly experience funding dry‐ups. Dry‐ups predict, but do not cause, future deterioration in bank performance. Furthermore, during periods of market stress, banks with high future performance tend to increase reliance on wholesale funding. We therefore fail to find evidence consistent with adverse selection models of funding market freezes. Our evidence is in line with theories highlighting heterogeneity between informed and uninformed lenders.

Risk Management in Financial Institutions

We study risk management in financial institutions using data on hedging of interest rate and foreign exchange risk. We find strong evidence that institutions with higher net worth hedge more, controlling for risk exposures, both across institutions and within institutions over time. For identification, we exploit net worth shocks resulting from loan losses due to drops in house prices. Institutions that sustain such shocks reduce hedging significantly relative to otherwise similar institutions. The reduction in hedging is differentially larger among institutions with high real estate exposure. The evidence is consistent with the theory that financial constraints impede both financing and hedging.

Cross-border Interbank contagion in the European Banking Sector

This paper studies the scope for cross-border contagion in the European banking sector using true bilateral exposure data. Using a model of sequential solvency and liquidity cascades in networks, we analyze geographical patterns of loss propagation from 2008 to 2012. We study the distribution of contagion outcomes after a common shock and an exogenous bank default over simulated networks of actual long- and short-term claims. We exploit a novel and unique dataset of money market transactions estimated from TARGET2 payments data. Our results show the critical impact of the underlying network structure on the propagation of losses. An econometric analysis of the determinants of contagion shows that the position of a bank in the network and its exposure to the riskiest counterparties are significantly correlated with default outcomes, behind its own financial ratios.

The Private Production of Safe Assets

Do claims on the private sector serve the role of safe assets? We answer this question using high-frequency panel data on prices and quantities of certificates of deposit (CD) and commercial paper (CP) issued in Europe. We show that only very short-term private securities benefit from a premium for safety. We then use several sources of variation to show that the issuance of short-term CDs strongly responds to measures of safety demand. The private production of safe assets is stronger for issuers with high credit worthiness, and breaks down during episodes of market stress. We conclude that even very short-term private assets are sensitive to changes in the information environment and should not be treated as equally safe at all times.

Who Bears Interest Rate Risk

We study the allocation of interest rate risk within the European banking sector using novel data. Banks’ exposure to interest rate risk is small on aggregate, but heterogeneous in the cross-section. Contrary to conventional wisdom, net worth is increasing in interest rates for approximately half of the institutions in our sample. Cross-sectional variation in banks’ exposures is driven by cross-country differences in loan-rate fixation conventions for mortgages. Banks use derivatives to partially hedge on-balance-sheet exposures. Residual exposures imply that changes in interest rates have redistributive effects within the banking sector. Received October 31, 2017; editorial decision August 30, 2018 by Editor Philip Strahan. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

Interest Rate Risk in Banking: A Survey

This paper surveys the theoretical and empirical literature on interest rate risk in banking. Theoretically, it considers the origins of interest rate risk and its allocation. Interest rate risk is non-diversifiable and does not originate from the banking sector, but from the potential time inconsistency between future aggregate demand and supply of consumption goods. Empirically, we discuss measurement and stylized facts. Banks bear part of total interest rate risk, but also engage in risk management and risk-sharing with non-financial agents. They transfer large amounts of risk to households and firms, by writing interest rate-contingent loan and deposit contracts. We consider the determinants of the aggregate exposure to interest rate risk and the pricing of marginal units of risk. Finally, interest rate policy, both conventional and non-conventional, is discussed.

Entrepreneurial Miscalculation and Business Cycles: How Interest Rate Targeting Distorts Capital Budgeting

Abstract This article, using Austrian Business Cycle Theory, shows how entrepreneurs and business managers are vulnerable to central bank monetary policies targeting interest rates. These policies distort market signals used as inputs in widely used capital budgeting metrics. Their reliance on nominal cash flows—together with their dependence on market-based discount rates, themselves directly or indirectly influenced by central bank policy—induces entrepreneurs to misestimate the real future profitability and feasibility of investment projects. Based on distorted market signals, entrepreneurs and business managers ignite an unsustainable economic boom. The divergence between ex ante and ex post profitable investment projects is widened because of business miscalculation leading to a cluster of errors that eventually results in the bursting of an economic boom. Therefore, although the exogenous distortion of market signals is a necessary condition of a business cycle, its ignition is purely endogenous.

Frictional Unemployment with Stochastic Bubbles

Bubbles are recurrent events, which contribute to both macroeconomic and employment volatility. We introduce stochastic bubbles in the standard search-and matching model of the labor market. The economy alternates between latent and bubbly states, each being associated with a distinct solution for the market value of firms (respectively, stable or explosive). Bubbles in firm value induce distortions in hiring decisions and wages, which we explicitly characterize. Faced with bubbles, the social planner optimally deviates from the standard Hosios efficiency condition. The optimal share of workers in total surplus must be above the elasticity of hiring rates, by a small but increasing amount as the bubble expands. Finally, our specification for bubbles significantly improves the quantitative ability of the model to match U.S. data, along both real and financial dimensions.