SteuerLLM: Local specialized large language model for German tax law analysis

Fuente: arXiv
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Main Authors: Wind, Sebastian, Sopa, Jeta, Schmid, Laurin, Jackl, Quirin, Kiefer, Sebastian, Wu, Fei, Mayr, Martin, Köstler, Harald, Wellein, Gerhard, Maier, Andreas, Arasteh, Soroosh Tayebi
Format: Preprint
Published: 2026
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author Wind, Sebastian
Sopa, Jeta
Schmid, Laurin
Jackl, Quirin
Kiefer, Sebastian
Wu, Fei
Mayr, Martin
Köstler, Harald
Wellein, Gerhard
Maier, Andreas
Arasteh, Soroosh Tayebi
author_facet Wind, Sebastian
Sopa, Jeta
Schmid, Laurin
Jackl, Quirin
Kiefer, Sebastian
Wu, Fei
Mayr, Martin
Köstler, Harald
Wellein, Gerhard
Maier, Andreas
Arasteh, Soroosh Tayebi
contents Large language models (LLMs) demonstrate strong general reasoning and language understanding, yet their performance degrades in domains governed by strict formal rules, precise terminology, and legally binding structure. Tax law exemplifies these challenges, as correct answers require exact statutory citation, structured legal argumentation, and numerical accuracy under rigid grading schemes. We algorithmically generate SteuerEx, the first open benchmark derived from authentic German university tax law examinations. SteuerEx comprises 115 expert-validated examination questions spanning six core tax law domains and multiple academic levels, and employs a statement-level, partial-credit evaluation framework that closely mirrors real examination practice. We further present SteuerLLM, a domain-adapted LLM for German tax law trained on a large-scale synthetic dataset generated from authentic examination material using a controlled retrieval-augmented pipeline. SteuerLLM (28B parameters) consistently outperforms general-purpose instruction-tuned models of comparable size and, in several cases, substantially larger systems, demonstrating that domain-specific data and architectural adaptation are more decisive than parameter scale for performance on realistic legal reasoning tasks. All benchmark data, training datasets, model weights, and evaluation code are released openly to support reproducible research in domain-specific legal artificial intelligence. A web-based demo of SteuerLLM is available at https://steuerllm.i5.ai.fau.de.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11081
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SteuerLLM: Local specialized large language model for German tax law analysis
Wind, Sebastian
Sopa, Jeta
Schmid, Laurin
Jackl, Quirin
Kiefer, Sebastian
Wu, Fei
Mayr, Martin
Köstler, Harald
Wellein, Gerhard
Maier, Andreas
Arasteh, Soroosh Tayebi
Computation and Language
Artificial Intelligence
Machine Learning
Large language models (LLMs) demonstrate strong general reasoning and language understanding, yet their performance degrades in domains governed by strict formal rules, precise terminology, and legally binding structure. Tax law exemplifies these challenges, as correct answers require exact statutory citation, structured legal argumentation, and numerical accuracy under rigid grading schemes. We algorithmically generate SteuerEx, the first open benchmark derived from authentic German university tax law examinations. SteuerEx comprises 115 expert-validated examination questions spanning six core tax law domains and multiple academic levels, and employs a statement-level, partial-credit evaluation framework that closely mirrors real examination practice. We further present SteuerLLM, a domain-adapted LLM for German tax law trained on a large-scale synthetic dataset generated from authentic examination material using a controlled retrieval-augmented pipeline. SteuerLLM (28B parameters) consistently outperforms general-purpose instruction-tuned models of comparable size and, in several cases, substantially larger systems, demonstrating that domain-specific data and architectural adaptation are more decisive than parameter scale for performance on realistic legal reasoning tasks. All benchmark data, training datasets, model weights, and evaluation code are released openly to support reproducible research in domain-specific legal artificial intelligence. A web-based demo of SteuerLLM is available at https://steuerllm.i5.ai.fau.de.
title SteuerLLM: Local specialized large language model for German tax law analysis
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2602.11081