Finance

Discrete mathematics

Actuarial science

Dynamic risk measure

Subadditivity

Risk management

Mathematics

Financial economics

Mathematical optimization

Quantile

Pareto principle

Coherent risk measure

Econometrics

Economics

Programming language

Arrow

Portfolio

Computer science

Risk measure

Value at risk

Expected shortfall

Operations Research

We address the problem of risk sharing among agents using a two-parameter class of quantile-based risk measures, the so-called range-value-at-risk (RVaR), as their preferences. The family of RVaR includes the value-at-risk (VaR) and the expected shortfall (ES), the two popular and competing regulatory risk measures, as special cases. We first establish an inequality for RVaR-based risk aggregation, showing that RVaR satisfies a special form of subadditivity. Then, the Pareto-optimal risk sharing problem is solved through explicit construction. To study risk sharing in a competitive market, an Arrow–Debreu equilibrium is established for some simple yet natural settings. Furthermore, we investigate the problem of model uncertainty in risk sharing and show that, in general, a robust optimal allocation exists if and only if none of the underlying risk measures is a VaR. Practical implications of our main results for risk management and policy makers are discussed, and several novel advantages of ES over VaR from the perspective of a regulator are thereby revealed. The e-companion is available at https://doi.org/10.1287/opre.2017.1716 .

Quantile-Based Risk Sharing