Uncertainty-Adjusted Sorting for Asset Pricing with Machine Learning
Yan Liu, Ye Luo, Zigan Wang, Xiaowei Zhang
TL;DR
This paper addresses how predictive uncertainty can be incorporated into ML-based asset pricing. It introduces uncertainty-adjusted sorting, which uses asset-specific prediction bounds around point forecasts to form long and short portfolios, rather than relying on point predictions alone. The approach is model-agnostic and derived from cross-validated residuals pooled at the asset level, enabling robust performance gains—especially for flexible models—through volatility reduction and improved ranking stability. Empirically on five decades of U.S. equity data, the method improves Sharpe ratios, remains effective under transaction costs, and its benefits hinge on correctly aligning uncertainty with individual assets and market states, rather than on aggregate volatility timing. The findings suggest predictive uncertainty is economically meaningful and should be integrated into cross-sectional portfolio decisions to enhance risk-adjusted performance in ML-driven asset pricing.
Abstract
Machine learning is central to empirical asset pricing, but portfolio construction still relies on point predictions and largely ignores asset-specific estimation uncertainty. We propose a simple change: sort assets using uncertainty-adjusted prediction bounds instead of point predictions alone. Across a broad set of ML models and a U.S. equity panel, this approach improves portfolio performance relative to point-prediction sorting. These gains persist even when bounds are built from partial or misspecified uncertainty information. They arise mainly from reduced volatility and are strongest for flexible machine learning models. Identification and robustness exercises show that these improvements are driven by asset-level rather than time or aggregate predictive uncertainty.
