📄 Abstract
Abstract: 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.
Key Contributions
This paper pioneers the exploration of merging Continual Pre-training (CPT) models for creating domain-specialized LLMs, specifically in finance. It proposes a novel three-stage evaluation framework and assesses existing merging techniques (Task Arithmetic, TIES, DARE-TIES), demonstrating that merging CPT experts can recover lost general knowledge and yield emergent cross-domain skills, offering a practical alternative to multi-skill training.
Business Value
Enables the creation of highly capable, domain-specific LLMs for finance more efficiently, reducing training costs and improving performance on specialized tasks.