Integration of GRI standards in the sustainability reporting of Borussia Dortmund: a longitudinal RAG analysis

Purpose This study examines how the public sustainability reporting of Borussia Dortmund GmbH & Co. KGaA (BVB), a listed German professional football club, can be assessed through a Global Reporting Initiative (GRI)-oriented retrieval-augmented generation (RAG) workflow. The paper has a dual, case-specific purpose: to describe longitudinal disclosure patterns in BVB reports and to evaluate the methodological usefulness and boundaries of RAG-assisted report analysis. Design/methodology/approach The study uses a longitudinal single-case design based on eight public BVB sustainability reports covering the 2016/17 to 2023/24 reporting periods. Public PDF reports were converted into machine-readable text, segmented into overlapping chunks, embedded, retrieved through a Facebook AI Similarity Search (FAISS) vector store and analysed with standardised prompts aligned with the eight GRI reporting principles. Ratings were interpreted as RAG-derived evidence scores and manually cross-checked against retrieved report passages. Findings The RAG-derived scores indicate moderate and fluctuating evidence for GRI-oriented reporting quality rather than a monotonic improvement. Accuracy, balance, timeliness, and verifiability mostly receive medium-to-high scores, while completeness, sustainability context, and the clarity of later reporting remain more uneven. The results should not be read as legal compliance findings or assurance-type verification, but rather as a usable framework to semi-automate information extraction from sustainability reports of professional sport organisations. Research limitations/implications The study is limited to one club, public textual report content, and one RAG configuration. It demonstrates how RAG can structure disclosure review, but also shows that expert judgement remains necessary. Practical implications The paper provides a transparent workflow and concrete reporting recommendations for clubs preparing more traceable, comparable, and standard-oriented sustainability disclosures. Social implications Sustainability has become one of the most dominant issues shaping the strategic orientation of sport organizations in the twenty-first century. Professional football clubs, as globally visible and economically powerful entities, are increasingly expected to demonstrate environmental, social, and governance (ESG) responsibility. Their influence extends beyond sporting performance, reaching fans, communities, sponsors, and policymakers. Consequently, stakeholders now demand transparent reporting of sustainability commitments. Emerging regulatory governance further transforms sustainability from a voluntary communication practice into a key component of organizational legitimacy. Originality/value The study connects sport sustainability reporting, GRI-based reporting principles and RAG-assisted document analysis in a longitudinal football case.