Abstract: The recovery (estimation) of asset return risk-neutral densities from cross-sectional option prices rely on strong model assumptions. At the same time, model-free recovery methods exist (see, e.g., Shimko (1993), Aït-Sahalia and Lo (2000), Figlewski (2010)), but they depend on the inter-/extra-polation of implied volatilities and the Black-Scholes formula. Both the model-based methods and the model-free methods work just fine for liquid, data-rich index options, but become brittle for illiquid, noisy stock options. We develop the Economics-Aware Gaussian Process which encodes the static no-arbitrage conditions ino the learned option price curves. Using the EAGP, we construct model-free stock-level RND aggregating both information from OTM call and put options. The EAGP-based RND improves the informativeness of a variety of metrics of stock returns, including the option-implied VaR, ES and moment-based metrics.
Example of the EAGP-recovered RNDs for ticker IBM
“Bridging Structured Knowledge and Data: A Unified Framework with Finance Applications”[SSRN][arXiv] Coauthored with: Yi Cao, Zexun Chen, Lin William Cong, Guangyan Gan Presented at: FoFI (Lancaster University Management School) 2026, ABFER 2026*, 中国金融科技学术年会 CFTRC 2026*, 42nd International Conference of the French Finance Association (AFFI), 5th Annual Hong Kong Conference on FinTech and AI in Finance†, ESIF 2026†, SoFiE 2026†, EFMA 2026†, 2nd Frontiers in Finance Conference (中科大)†, 中国金融学术年会 CFRC 2026†, CES 2026 China Conference†, ESEM 2026†
Abstract: We develop Structured-Knowledge-Informed Neural Networks, a unified estimation framework that embeds theoretical, simulated, previously learned, or cross-domain insights as differentiable constraints within flexible neural function approximation. SKINNs jointly estimate neural network parameters and economically meaningful structural parameters in a single optimization problem, nesting approaches such as functional GMM, Bayesian updating, transfer learning, PINNs, and surrogate modeling. In an illustrative financial application to option pricing, SKINNs improve out-of-sample valuation and hedging performance, particularly at longer horizons and during high-volatility regimes, while recovering economically interpretable structural parameters with improved stability relative to conventional calibration. More broadly, SKINNs provide a general econometric framework for combining model-based reasoning with high-dimensional, data-driven estimation.