[Competition among trading platforms has considerably reduced trading fees in stock markets. We show that this evolution is not necessarily beneficial to investors. Although they increase gains from trade when a trade happens, lower trading costs can induce investors to post limit orders with a smaller execution probability. In this case, gains from trade are realized less frequently and investors can be worse off. Our model has testable implications for the effects of trading fees and their breakdown between liquidity suppliers and liquidity demanders on limit order fill rates and bid-ask spreads.]

Abstract Both in the USA and in the Euro area, bank supervision is the joint responsibility of local and central supervisors. I study a model in which local supervisors do not internalize as many externalities as a central supervisor. Local supervisors are more lenient, but banks also have weaker incentives to hide information from them. These two forces can make a joint supervisory architecture optimal, with more weight put on centralized supervision when cross-border externalities are larger. Conversely, more centralized supervision endogenously encourages banks to integrate more cross-border. Due to this complementarity, the economy can be trapped in a suboptimal equilibrium with either too little or too much central supervision, when a superior equilibrium would be achievable.

Abstract We study “Algorithmic Market Makers” (AMs) that use Q-learning algorithms to set prices for a risky asset. We find that while AMs successfully adapt to adverse selection, they struggle to learn competitive pricing strategies. This failure is driven by limited experimentation and noisy feedback regarding the profitability of undercutting a competitor. Consequently, an increase in AMs’ profit volatility tends to result in less competitive market outcomes. These features leave identifiable patterns: for example, AMs earn higher rents in the absence of adverse selection, and their bid-ask spreads respond asymmetrically to symmetric shocks to their costs.

Competition among trading platforms has considerably reduced trading fees in stock markets. We show that this evolution is not necessarily beneficial to investors. Although they increase gains from trade when a trade happens, lower trading costs can induce investors to post limit orders with a smaller execution probability. In this case, gains from trade are realized less frequently and investors can be worse off. Our model has testable implications for the effects of trading fees and their breakdown between liquidity suppliers and liquidity demanders on limit order fill rates and bid-ask spreads.

We propose a framework to study regulatory complexity, based on concepts from computer science. We distinguish different dimensions of complexity, classify existing measures, develop new ones, compute them on three examples — Basel I, the Dodd–Frank Act, and the European Banking Authority’s reporting rules — and test them using experiments and a survey on compliance costs. We highlight two measures that capture complexity beyond the length of a regulation. We propose a quantitative approach to the policy trade-off between regulatory complexity and precision.

Abstract How do resolution frameworks affect the private restructuring of distressed banks? We model a bank’s shareholders and creditors negotiating a restructuring, under two frictions: asymmetric information about asset quality and externalities on the government. High-quality banks signal themselves by delaying the negotiation, which is socially inefficient. Public policies can improve welfare if they reduce the signaling motive or increase the negotiation surplus. Stricter bail-in rules make debt more information sensitive and increase delays. The bank chooses a capital structure with too little renegotiable debt, giving a new rationale, for example, for Total Loss Absorbing Capacity requirements.

ABSTRACT We use the introduction of a financial transaction tax (FTT) in France in 2012 to test competing theories on its impact. We find no support for the idea that an FTT improves market quality by affecting the composition of trading volume. Instead, our results are in line with the hypothesis that a lower trading volume reduces liquidity and in turn market quality. Consistent with theories of asset pricing under transaction costs, we document a shift in security holdings from short‐term to long‐term investors. Finally, we find that moderate aggregate effects on market quality can mask large adjustments made by individual agents.

ABSTRACT We propose a new model of trading in over‐the‐counter markets. Dealers accumulate inventories by trading with end‐investors and trade among each other to reduce their inventory holding costs. Core dealers use a more efficient trading technology than peripheral dealers, who are heterogeneously connected to core dealers and trade with each other bilaterally. Connectedness affects prices and allocations if and only if the peripheral dealers' aggregate inventory position differs from zero. Price dispersion increases in the size of this position. The model generates new predictions about the effects of dealers' connectedness and dealers' aggregate inventories on prices.

Abstract We review the extensive literature on systemic risk and connect it to the current regulatory debate. While we take stock of the achievements of this rapidly growing field, we identify a gap between two main approaches. The first one studies different sources of systemic risk in isolation, uses confidential data, and inspires targeted but complex regulatory tools. The second approach uses market data to produce global measures which are not directly connected to any particular theory, but could support a more efficient regulation. Bridging this gap will require encompassing theoretical models and improved data disclosure.

Abstract Supervision of multinational banks (MNBs) by national supervisors suffers from coordination failures. We show that supranational supervision solves this problem and decreases the public costs of an MNB’s failure, taking its organizational structure as given. However, the MNB strategically adjusts its structure to supranational supervision. It converts its subsidiary into a branch (or vice versa) to reduce supervisory monitoring. We identify the cases in which this endogenous reaction leads to unintended consequences, such as higher public costs and lower welfare. Current reforms should consider that MNBs adapt their organizational structures to changes in supervision. Received January 9, 2017; editorial decision September 15, 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.