Publication Date

9-2-2024

Document Type

Article

Organizational Units

Daniels College of Business, Reiman School of Finance

Keywords

Machine learning, Out-of-sample predictability, Pooling, Ensembles, Return predictability

Abstract

We evaluate US market return predictability using a novel data set of several hundred ag- gregated firm-level characteristics. We apply LASSO, Elastic Net, Random Forest, Neural Net, Extreme Gradient Boosting, and Light Gradient Boosting Machine methods and find these models experience large prediction errors that lead to forecast failures. However, winsorizing and pooling machine learning model forecasts provides consistent out-of-sample predictability. To assess robustness, we apply machine learning methods to high-dimensional data for Canada, China, Germany and the UK as well as the Goyal-Welch data. All machine learning models we consider, except for the ensemble pooled methods, fail to significantly predict returns across our samples, highlighting the importance of pooling, evaluating additional economies, and the fragility of individual machine learning methods. Our results shed light on the sparsity versus density debate as the degree of sparsity and variable importance evolves over time.

Copyright Date

9-11-2024

Copyright Statement / License for Reuse

Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.

Rights Holder

Erik Mekelburg and Jack Strauss

Provenance

Received from Elsevier

File Format

application/pdf

Language

English (eng)

Extent

25 pgs

File Size

3.26 MB

Publication Statement

Copyright is held by the Authors. User is responsible for all copyright compliance. This article was originally published as

Mekelburg, E., & Strauss, J. (2024). Pooling and Winsorizing Machine Learning Forecasts to Predict Stock Returns with High-Dimensional Data. Journal of Empirical Finance, 79, 101538. https://doi.org/10.1016/j.jempfin.2024.101538

Publication Title

Journal of Empirical Finance

Volume

79

First Page

101538

ISSN

0927-5398



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