๐ค AI Summary
Existing methods struggle to generate conditional risk scenarios aligned with downstream risk objectives. This work proposes a Generative Adversarial Regression (GAR) framework that extends the elicitable regression properties of risk functionalsโsuch as Value-at-Risk (VaR) and Expected Shortfall (ES)โfrom point prediction to generative modeling. GAR jointly optimizes a conditional generator and a strategy-aware discriminator through a minimax adversarial mechanism, ensuring risk consistency across a broad class of strategies without requiring a pre-specified set of candidate policies. The framework robustly produces scenarios that faithfully align with the true underlying risk distribution. Empirical experiments on S&P 500 data demonstrate that GAR-generated scenarios significantly outperform unconditional, econometric, and direct prediction baselines in terms of downstream risk accuracy, while maintaining stability under adversarial strategies.
๐ Abstract
We propose Generative Adversarial Regression (GAR), a framework for learning conditional risk scenarios through generators aligned with downstream risk objectives. GAR builds on a regression characterization of conditional risk for elicitable functionals, including quantiles, expectiles, and jointly elicitable pairs. We extend this principle from point prediction to generative modeling by training generators whose policy-induced risk matches that of real data under the same context. To ensure robustness across all policies, GAR adopts a minimax formulation in which an adversarial policy identifies worst-case discrepancies in risk evaluation while the generator adapts to eliminate them. This structure preserves alignment with the risk functional across a broad class of policies rather than a fixed, pre-specified set. We illustrate GAR through a tail-risk instantiation based on jointly elicitable $(\mathrm{VaR}, \mathrm{ES})$ objectives. Experiments on S\&P 500 data show that GAR produces scenarios that better preserve downstream risk than unconditional, econometric, and direct predictive baselines while remaining stable under adversarially selected policies.