Merging Continual Pretraining Models for Domain-Specialized LLMs: A Case Study in Finance

Fuente: arXiv
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Auteurs principaux: Ueda, Kentaro, Portet, François, Suwa, Hirohiko, Yasumoto, Keiichi
Format: Preprint
Publié: 2025
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author Ueda, Kentaro
Portet, François
Suwa, Hirohiko
Yasumoto, Keiichi
author_facet Ueda, Kentaro
Portet, François
Suwa, Hirohiko
Yasumoto, Keiichi
contents While LLMs excel at general tasks, they struggle in specialized domains like finance, requiring diverse skills in domain knowledge, mathematical reasoning, and multilingual processing. Merging domain-specific Continual Pre-training (CPT) "experts" offers a practical alternative to costly and unstable multi-skill training. However, unlike established Supervised Fine-Tuning (SFT) model-based merging, CPT model merging remains largely unexplored. We address this gap by creating financial LLMs from experts in finance, math, and Japanese. We propose a three-stage evaluation focusing on knowledge recovery, complementarity, and emergence, and assess three merging methods (Task Arithmetic, TIES, and DARE-TIES) on a comprehensive financial benchmark curated from 18 tasks across 8 established datasets. Results show that merging an expert with its base model recovers general knowledge lost during CPT, while merging experts improves performance and can yield emergent cross-domain skills. Among the methods, Task Arithmetic performs strongly but is hyperparameter-sensitive, whereas TIES is more robust. Our findings also suggest that while model similarity correlates with merging success, emergent skills depend on more complex factors. This work presents the first foundational analysis of CPT model merging, establishing a principled framework and providing clear guidance for building multi-skill LLMs from existing assets.
format Preprint
id arxiv_https___arxiv_org_abs_2511_02451
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Merging Continual Pretraining Models for Domain-Specialized LLMs: A Case Study in Finance
Ueda, Kentaro
Portet, François
Suwa, Hirohiko
Yasumoto, Keiichi
Computation and Language
While LLMs excel at general tasks, they struggle in specialized domains like finance, requiring diverse skills in domain knowledge, mathematical reasoning, and multilingual processing. Merging domain-specific Continual Pre-training (CPT) "experts" offers a practical alternative to costly and unstable multi-skill training. However, unlike established Supervised Fine-Tuning (SFT) model-based merging, CPT model merging remains largely unexplored. We address this gap by creating financial LLMs from experts in finance, math, and Japanese. We propose a three-stage evaluation focusing on knowledge recovery, complementarity, and emergence, and assess three merging methods (Task Arithmetic, TIES, and DARE-TIES) on a comprehensive financial benchmark curated from 18 tasks across 8 established datasets. Results show that merging an expert with its base model recovers general knowledge lost during CPT, while merging experts improves performance and can yield emergent cross-domain skills. Among the methods, Task Arithmetic performs strongly but is hyperparameter-sensitive, whereas TIES is more robust. Our findings also suggest that while model similarity correlates with merging success, emergent skills depend on more complex factors. This work presents the first foundational analysis of CPT model merging, establishing a principled framework and providing clear guidance for building multi-skill LLMs from existing assets.
title Merging Continual Pretraining Models for Domain-Specialized LLMs: A Case Study in Finance
topic Computation and Language
url https://arxiv.org/abs/2511.02451