Dynamic portfolio selection under range value-at-risk with logarithmic returns

By Hui Mi, Yuzhe Pan, Zuo Quan Xu

Rating

1776
Battle Count: 50

Relevance

8/10
Highly relevant for quantitative portfolio managers using tail-risk measures. It provides explicit strategies for RVaR, bridging the gap between VaR and ES, and highlights non-monotonic effects of risk parameters on leverage.

Implementation Complexity

7/10
Requires solving for convex envelopes and handling piecewise-defined optimal wealth functions. Closed-form solutions are provided for constant coefficients, but general implementation requires numerical inversion of distribution functions and careful handling of the two geometric scenarios.

Reproducibility

3/5
The paper provides full analytical derivations, closed-form solutions for constant coefficients, and specific numerical parameters (Black-Scholes market, r=0.05, sigma=0.15, theta=0.4). However, no public code repository is linked in the text.

Abstract

This paper studies continuous-time portfolio selection under Range Value-at-Risk (RVaR), with both portfolio performance and risk evaluated in terms of logarithmic returns. We formulate a mean–RVaR problem in a continuous-time financial market and reduce the dynamic optimization to a static quantile problem. Using quantile representation, Lagrangian optimization, and convexification, we characterize the optimal terminal wealth through the convex envelope of an RVaR-specific transformed weighting function. The RVaR-specific convex envelope exhibits two distinct geometric configurations. Under Scenario 1, the terminal wealth has a VaR-type structure: the minimum-RVaR payoff is digital-option-like, whereas for 0<λ<1 it consists of two growth-optimal regions separated by a constant-payoff region. Under Scenario 2, the convex envelope is determined either by a supporting line connecting an interior contact point to the endpoint or by a common supporting line with two interior contact points, leading to a richer multi-region payoff structure. We further show that the RVaR solutions reduce to their VaR and Expected Shortfall (ES) counterparts as β\downarrowα and α=0, respectively. Under constant investment opportunities, we also derive closed-form wealth processes and replicating portfolio strategies. Numerical results show that the effects of (α,β,λ) on risky-asset exposure are nonlinear and generally non-monotone. In particular, when α>0, pure minimum-RVaR optimization may assign zero terminal wealth in sufficiently bad states because the extreme quantile region [0,α) is excluded from the RVaR criterion. These results clarify how interval-based quantile risk control shapes state-dependent portfolio payoffs and connects RVaR with its VaR and ES limiting cases.

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