Uncovering Representation Bias for Investment Decisions in Open-Source Large Language Models

Fuente: arXiv
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Auteurs principaux: Dimino, Fabrizio, Saxena, Krati, Sarmah, Bhaskarjit, Pasquali, Stefano
Format: Preprint
Publié: 2025
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author Dimino, Fabrizio
Saxena, Krati
Sarmah, Bhaskarjit
Pasquali, Stefano
author_facet Dimino, Fabrizio
Saxena, Krati
Sarmah, Bhaskarjit
Pasquali, Stefano
contents Large Language Models are increasingly adopted in financial applications to support investment workflows. However, prior studies have seldom examined how these models reflect biases related to firm size, sector, or financial characteristics, which can significantly impact decision-making. This paper addresses this gap by focusing on representation bias in open-source Qwen models. We propose a balanced round-robin prompting method over approximately 150 U.S. equities, applying constrained decoding and token-logit aggregation to derive firm-level confidence scores across financial contexts. Using statistical tests and variance analysis, we find that firm size and valuation consistently increase model confidence, while risk factors tend to decrease it. Confidence varies significantly across sectors, with the Technology sector showing the greatest variability. When models are prompted for specific financial categories, their confidence rankings best align with fundamental data, moderately with technical signals, and least with growth indicators. These results highlight representation bias in Qwen models and motivate sector-aware calibration and category-conditioned evaluation protocols for safe and fair financial LLM deployment.
format Preprint
id arxiv_https___arxiv_org_abs_2510_05702
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Uncovering Representation Bias for Investment Decisions in Open-Source Large Language Models
Dimino, Fabrizio
Saxena, Krati
Sarmah, Bhaskarjit
Pasquali, Stefano
Computational Finance
Artificial Intelligence
Large Language Models are increasingly adopted in financial applications to support investment workflows. However, prior studies have seldom examined how these models reflect biases related to firm size, sector, or financial characteristics, which can significantly impact decision-making. This paper addresses this gap by focusing on representation bias in open-source Qwen models. We propose a balanced round-robin prompting method over approximately 150 U.S. equities, applying constrained decoding and token-logit aggregation to derive firm-level confidence scores across financial contexts. Using statistical tests and variance analysis, we find that firm size and valuation consistently increase model confidence, while risk factors tend to decrease it. Confidence varies significantly across sectors, with the Technology sector showing the greatest variability. When models are prompted for specific financial categories, their confidence rankings best align with fundamental data, moderately with technical signals, and least with growth indicators. These results highlight representation bias in Qwen models and motivate sector-aware calibration and category-conditioned evaluation protocols for safe and fair financial LLM deployment.
title Uncovering Representation Bias for Investment Decisions in Open-Source Large Language Models
topic Computational Finance
Artificial Intelligence
url https://arxiv.org/abs/2510.05702