This paper introduces the Swiss Leading Decision Summarization (SLDS) dataset, a new multilingual legal summarization dataset containing 18,000 decisions of the Swiss Federal Court of Justice (German, French, and Italian). To reduce the time-consuming nature of legal research, we focus on automated decision summaries (headnotes). Using the SLDS dataset, we fine-tune and evaluate three mT5 variants and proprietary models for German headnote generation. The evaluation results demonstrate that while the proprietary models perform well in both zero-shot and one-shot settings, fine-tuned smaller models are also competitive. The dataset is made publicly available, and we anticipate that this will facilitate research in multilingual legal summarization and the development of supporting technologies for legal professionals.