Vector-Quantized Discrete Latent Factors Meet Financial Priors: Dynamic Cross-Sectional Stock Ranking Prediction for Portfolio Construction

TL;DR

This paper introduces PRISM-VQ, a novel dynamic factor model that combines financial priors, vector quantization, and mixture-of-experts to improve stock return prediction and portfolio construction.

Contribution

It presents a new framework integrating expert priors with vector-quantized latent factors and a structure-conditioned mixture-of-experts for better market modeling.

Findings

Improved cross-sectional return prediction on CSI 300 and S&P 500.

Enhanced portfolio performance over strong baselines.

Preserved interpretability of the model.

Abstract

Predicting cross-sectional stock returns is challenging due to low signal-to-noise ratios and evolving market regimes. Classical factor models offer interpretability but limited flexibility, while deep learning models achieve strong performance yet often underutilize financial priors. We address this gap with PRISM-VQ (PRior-Informed Stock Model with Vector Quantization), a dynamic factor framework that integrates expert prior factors, vector-quantized discrete latent factors learned from cross-sectional structure, and a structure-conditioned Mixture-of-Experts to generate time-varying factor loadings. Vector quantization acts as an information bottleneck that suppresses noise while capturing robust market structure, with discrete codes serving both as latent factors and as routing signals for temporal expert specialization. Experiments on CSI 300 and S&P 500 show consistent improvements in cross-sectional return prediction and portfolio performance over strong baselines while preserving interpretability. Our code is available at https://github.com/finxlab/PRISM-VQ.