Research

Paper

TESTING February 23, 2026

Zero Variance Portfolio

Authors

Jinyuan Chang, Yi Ding, Zhentao Shi, Bo Zhang

Abstract

When the number of assets is larger than the sample size, the minimum variance portfolio interpolates the training data, delivering pathological zero in-sample variance. We show that if the weights of the zero variance portfolio are learned by a novel ``Ridgelet'' estimator, in a new test data this portfolio enjoys out-of-sample generalizability. It exhibits the double descent phenomenon and can achieve optimal risk in the overparametrized regime when the number of assets dominates the sample size. In contrast, a ``Ridgeless'' estimator which invokes the pseudoinverse fails in-sample interpolation and diverges away from out-of-sample optimality. Extensive simulations and empirical studies demonstrate that the Ridgelet method performs competitively in high-dimensional portfolio optimization.

Metadata

arXiv ID: 2602.19462
Provider: ARXIV
Primary Category: stat.ME
Published: 2026-02-23
Fetched: 2026-02-24 04:38

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Raw Data (Debug)
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