Gijsbert Zwart

Competition for traders and risk

The financial crisis has been attributed partly to perverse incentives for traders at banks and has led policy makers to propose regulation of banks’ remuneration packages. We explain why poor incentives for traders cannot be fully resolved by only regulating the bank’s top executives, and why direct intervention in trader compensation is called for. We present a model with both trader moral hazard and adverse selection on trader abilities. We demonstrate that as competition on the labor market for traders intensifies, banks optimally offer top traders contracts inducing them to take more risk, even if banks fully internalize the costs of negative outcomes. In this way, banks can reduce the surplus they have to offer to lower ability traders. In addition, we find that increasing banks’ capital requirements does not unambiguously lead to reduced risk-taking by their top traders.

Competition Leverage: How the Demand Side Affects Optimal Risk Adjustment

We study optimal risk adjustment in imperfectly competitive health insurance markets when high-risk consumers are less likely to switch insurer than low-risk consumers. First, we find that insurers still have an incentive to select even if risk adjustment perfectly corrects for cost differences among consumers. Consequently, the outcome is not efficient even if cost differences are fully compensated. To achieve first best, risk adjustment should overcompensate for serving high-risk agents to take into account the difference in mark-ups among the two types. Second, the difference in switching behavior creates a trade off between efficiency and consumer welfare. Reducing the difference in risk adjustment subsidies to high and low types increases consumer welfare by leveraging competition from the elastic low-risk market to the less elastic high-risk market. Finally, mandatory pooling can increase consumer surplus even further, at the cost of efficiency.

Optimal Regulation of Lumpy Investments

When a monopolist has discretion over the timing of infrastructure investments, regulation of post-investment prices interferes with incentivizing socially optimal investment timing. In a model of regulated lumpy investment under uncertainty, we study regulation when the regulator can condition price caps on investment timing. We analyse optimal regulation when there is asymmetric information on investment costs and regulation has to respect a budget constraint. We show that optimal regulation involves a price cap that decreases as a function of the monopolists chosen investment time.

Selective Contracting and Foreclosure in Health Care Markets

We analyze exclusive contracts between health care providers and insurers in a model where some consumers choose to stay uninsured. In case of a monopoly insurer, exclusion of a provider changes the distribution of consumers who choose not to insure. Although the foreclosed care provider remains active in the market for the non-insured, we show that exclusion leads to anti-competitive effects on this non-insured market. As a consequence exclusion can raise industry profits, and then occurs in equilibrium. Under competitive insurance markets, the anticompetitive exclusive equilibrium survives. Uninsured consumers, however, are now not better off without exclusion. Competition among insurers raises prices in equilibria without exclusion, as a result of a horizontal analogue to the double marginalization effect. Instead, under competitive insurance markets exclusion is desirable as long as no provider is excluded by all insurers.

Optimal regulation of network expansion

We model the regulation of irreversible capacity expansion by a firm with private information about capacity costs, where investments are financed from the firms cash flows and demand is stochastic. The optimal mechanism is implemented by a revenue tax that increases with the price cap. If the asymmetric information has large support, then the optimal mechanism consists of a laissez†faire regime for low†cost firms. That is, the firms price cap corresponds to that of an unregulated monopolist, and it is not taxed. This “maximal distortion at the top†is necessary to provide information rents, as direct subsidies are not feasible.

Community Rating in Health Insurance: Trade-Off Between Coverage and Selection

We analyze the role of community rating in the optimal design of a risk adjustment scheme in competitive health insurance markets when insurers have better information on their customers’ risk profiles than the sponsor of health insurance. The sponsor offers insurers a menu of risk adjustment schemes to elicit this information. The optimal scheme includes a voluntary reinsurance option. Additionally, the scheme should sometimes be complemented by a community rating requirement. The resulting inefficient coverage of low-cost types lowers the sponsor’s cost of separating different insurer types. This allows the sponsor to redistribute more rents from low-cost to high-cost consumers.

Optimal Procurement and Investment in New Technologies under Uncertainty

We study a buyers optimal investment strategy for new technologies when costs evolve stochastically and are private information to the suppliers. In a continuous time setting, we show how the asymmetric information on the stochastic variables leads to delays in investment compared to the real option benchmark. We also suggest a payment structure that implements the buyers optimal investment timing as a Vickrey-type auction.

Inside Liquidity in Competitive Markets

In CPB Discussion Paper 209 we study incentives of financial intermediaries to reserve liquidity given that they can rely on the interbank market for their liquidity needs. Intermediaries can partially pledge their assets to each other, but not to the rest of the economy. Therefore liquidity provision is endogenous. We show that if the probability of a crisis is large or if assets are slightly pledgeable, then all intermediaries reserve liquidity. However, if the probability of a crisis is small or if assets are highly pledgeable, then intermediaries segregate ex ante: some reserve no liquidity, others reserve to the maximum and become liquidity providers. This segregation arises, because in the latter case the crisis short-term rate exceeds the returns on long-term investments, while at the same time higher liquidity holdings also increase survival probability. Together, these two effects result in increasing marginal returns to liquidity in the crisis state, and, consequently, segregation ex ante. In either equilibrium, aggregate liquidity is too small if assets are not fully pledgeable. Minimum liquidity requirements only improve welfare in the symmetric equilibrium. Marginally lowering the interest rate causes a marginal crowding-out of private liquidity with public liquidity in the symmetric equilibrium, but a full crowding-out in the asymmetric equilibrium.

Competition for Access: Spectrum Rights and Downstream Access in Wireless Telecommunications

We analyse downstream access and capacity choice in the market for wireless telecommunications, where spectrum rights are owned by vertically integrated duopolists and may be traded. In the market for wireless telecommunications, radio spectrum is an essential input. Prior to network construction, the incumbents may offer contracts for capacity to an entrant, granting service-based access on the network they will construct. Alternatively, when spectrum trading is allowed, they may sell part of their license, allowing the entrant to build its own network and enter as an infrastructure player. We find that in this Cournot setting, access is generally provided, as incumbents compete to appropriate the profits of serving a differentiated market through the entrant. Although selling spectrum rights instead of network capacity leads to a loss of economies of scale in infrastructure construction, infrastructure-based entry may dominate as a result of a strategic effect. By delegating capacity choice to the entrant, the access providing incumbent can commit to compete more aggressively, causing its rival incumbent to reduce capacity. A lower aggregate capacity will increase prices and thereby profits.