q-fin.RMAug 18, 2026

Communicating Credit Risk with Large Language Models: Evaluation of Explanations from Standard and Alternative Data-Based Models

Authors: Sahab Zandi, Noah Kostesku, Christophe Mues, María Óskarsdóttir, Cristián Bravo

Organizations: Department of Statistical and Actuarial Sciences, Western University, London, Canada · Department of Computer Science, Western University, London, Canada · University of Southampton Business School, University of Southampton, Southampton, United Kingdom · Centre for Operational Research, Management Sciences and Information Systems, University of Southampton, Southampton, United Kingdom · School of Mathematical Sciences, University of Southampton, Southampton, United Kingdom · Department of Computer Science, Reykjavik University, Reykjavik, Iceland

Abstract

Credit decisioning is a high-stakes task in which model outputs must be accurate and explainable to support compliant decisions. Although modern credit risk models such as eXtreme Gradient Boosting (XGBoost) and Graph Neural Networks (GNNs) improve predictive performance, their explanations are often too technical for stakeholders creating communication gaps that can shape approvals, denials, and fairness judgments. We examine whether Large Language Models (LLMs) can serve as explanation layers that translate post-hoc explanation artefacts into stakeholder-appropriate risk narratives. Using Freddie Mac single-family loan-level data, we develop three pipelines: standard tabular (XGBoost + SHAP), and two with alternative data, a pure network-based (GNN + GNNExplainer), and a bimodal one (combining tabular and network data). We generate narratives with three LLM configurations: a small fine-tuned LLM (Gemma 3 4B), a large fine-tuned LLM (DeepSeek R1 70B), and a zero-shot commercial LLM (Gemini 2.5). Explanation quality is evaluated through automated checks across all pipelines and a human study of bimodal explanations comparing credit risk professionals and non-professionals on eight decision-relevant dimensions. We have three main findings. First, the pipeline accounts for higher variance in evidence-grounding scores than the language model, meaning that the binding constraint on explanation quality is the evidence representation, not the model used. Second, the explanation narratives reliably name the influential factors but are less reliable when stating the direction of influence, which may be consequential for adverse-action communication. Finally, professionals apply stricter evidentiary standards than non-professionals. We discuss implications for the governance of risk models, including deployment considerations and the value of domain-aligned LLMs in regulated credit settings.

Figures & tables

Appendix figures & tables11 assets

Supplementary material from the paper’s appendix.

Appendix

Explore similar work

CardsList
  1. Could Large Language Models work as Post-hoc Explainability Tools in Credit Risk Models?

    Feb 21, 2026Wenxi Geng, Dingyuan Liu, Liya Li +1Explainable Artificial IntelligenceExplainability Evaluation

  2. Accurate Ensembles, Fragile Narratives: Multi-Scale Stacking and a Fidelity Audit of LLM-Generated Explanations for Credit Risk

    Aug 8, 2026Gregorius Reynaldi Pratama, Kuo-Kun TsengFeature AttributionFaithfulness of Language Model Explanations