ReimburseBench: Benchmarking LMMs as Full-Workflow Auditors for Financial Internal Control

Libin Zhan, Wuyou Mao, Xiang Li, Enci Zhang, Qi Yang, Shujian Zhu, Yingtian Hu, Wentao Ye, Haobo Wang, Ziman Li, Jie Zhang, Wang Dong, Jun Chen


Abstract
Expense reimbursement internal control is a high-stakes corporate finance task that combines multimodal, visually rich evidence (e.g., receipts and approval forms), firm-specific policy text, and multi-step compliance reasoning. No existing benchmark evaluates large multimodal models (LMMs) in this domain. We introduce ReimburseBench, the first benchmark targeting full-workflow multimodal audit reasoning in corporate internal control. It comprises 151 expert-constructed reimbursement workflows, each packaging an application, receipts and supporting documents, and a firm-specific policy, evaluated by a process-level rubric grounded in twelve auditing logic points. Benchmarking nine frontier and locally deployable systems, we find the strongest attains only 72.5%, and no model exceeds 47.7% on hard workflows. Beyond this aggregate score, risk-aware, process-level evaluation surfaces three structural findings: (i) a persistent gap between binary admissibility judgment and precise quantitative computation; (ii) a systematic lenient bias in monetary predictions that poses deployment risk; and (iii) a performance pattern consistent with compositional-generalization difficulties under realistic workflow load. We provide ReimburseBench as a testbed for advancing LMMs toward trustworthy financial systems. Data and code: https://github.com/ikerzhan/ReimburseBench.
Anthology ID:
2026.findings-emnlp.821
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
17403–17425
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.821/
DOI:
10.18653/2026.findings-emnlp.821
Bibkey:
Cite (ACL):
Libin Zhan, Wuyou Mao, Xiang Li, Enci Zhang, Qi Yang, Shujian Zhu, Yingtian Hu, Wentao Ye, Haobo Wang, Ziman Li, Jie Zhang, Wang Dong, and Jun Chen. 2026. ReimburseBench: Benchmarking LMMs as Full-Workflow Auditors for Financial Internal Control. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 17403–17425, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ReimburseBench: Benchmarking LMMs as Full-Workflow Auditors for Financial Internal Control (Zhan et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.821.pdf