From Sustainability Disclosure to Accounting Connectivity: Evidence from the First ESRS Reports of Portuguese Listed Companies

This study examines accounting connectivity between FY2024 sustainability statements prepared under the European Sustainability Reporting Standards (ESRS) and corresponding IFRS financial statements. Using the full eligible population of 22 Portuguese companies listed on the Euronext Lisbon regulated market, it develops and applies a 26-item Accounting Connectivity Index (ACI) across four dimensions: Referential, Quantitative, Methodological, and Accounting Consequence Connectivity. The analysis combines structured content analysis with qualitative assessment of sustainability-to-accounting pathways. ACI scores range from 17.1 to 94.8, with a population mean of 57.1. Quantitative Connectivity is the strongest and most widespread dimension, largely reflecting traceable relationships between EU Taxonomy metrics and financial-statement amounts. Accounting Consequence Connectivity, by contrast, is concentrated in seven companies. The results show that quantitative traceability does not necessarily imply substantive accounting connectivity and support a distinction between disclosure connectivity and integration into accounting assumptions, estimates, measurement, and financial-statement outcomes. Connectivity pathways also differ across sectoral and accounting contexts. The findings remain stable under alternative population definitions, item specifications, and weighting approaches. The study contributes a replicable, sector-neutral framework for evaluating the nature and depth of connectivity between sustainability and financial reporting.