PRISM: Prompt-Refined In-Context System Modeling for Financial Retrieval

Chun Chet Ng, Jia Yu Lim, Zhen Hao Chu, Yixi Zhou, Low Wei Zeng


Abstract
Deploying LLMs for financial information retrieval demands accuracy, cost efficiency, and reproducibility, yet most approaches require expensive fine-tuning. PRISM is a training-free framework that composes three deployable modules (prompt engineering, in-context learning, and a candidate refinement module) with a boundary-condition study of multi-agent coordination for financial document retrieval. On FiQA-2018, stacked reranking and k-reciprocal encoding raise Recall@100 from 0.7783 to 0.8326. On FinAgentBench, a Cohere-refined top-50 pool yields a higher observed end-to-end NDCG@5, below this evaluation’s minimum detectable effect, while cutting per-query cost by about 35%. Added complexity does not always pay off: k-reciprocal encoding stops helping once the upstream stage is already high-recall, and multi-agent coordination is not a default for fine-grained chunk ranking. Matched pairs that hold prompt, model, and exemplars fixed lose 0.0702 and 0.0681 combined NDCG@5 to their single-path controls, and the whole gap sits at the chunk stage. We release an expert-annotated FinAgentBench evaluation set, together with a label-robustness sweep over 16 alternative ground-truth constructions, restoring a reproducible evaluation path after the original evaluator went offline. Without fine-tuning, PRISM placed third on the official FinAgentBench private leaderboard (leaderboard basis, NDCG@5 0.71181), reaches NDCG@10 0.6197 on FiQA-2018, and 98% accuracy on FinanceBench. We report per-query latency, token, and dollar accounting across roughly 40 configurations, present the quality–cost–latency Pareto frontier, and introduce FACET, a transparent SLA-specific scalarization for choosing among non-dominated configurations. Code and dataset are released at https://bit.ly/prism-ailens.
Anthology ID:
2026.emnlp-industry.99
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
1674–1737
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.99/
DOI:
Bibkey:
Cite (ACL):
Chun Chet Ng, Jia Yu Lim, Zhen Hao Chu, Yixi Zhou, and Low Wei Zeng. 2026. PRISM: Prompt-Refined In-Context System Modeling for Financial Retrieval. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 1674–1737, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
PRISM: Prompt-Refined In-Context System Modeling for Financial Retrieval (Ng et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.99.pdf