As sustainability reporting becomes more prevalent, ESG assurance—third-party verification of ESG disclosures—has been suggested in the literature as a possible way for firms to signal their commitment to sustainability; however, whether it truly reflects genuine dedication or merely symbolic behavior remains uncertain. This study examines whether ESG assurance signals true commitment by assessing the alignment between assured items and ESG materiality. Using hand-collected data from STOXX Europe 600 firms (2017–2022) and the SASB Materiality Map, we classify assured items as material or immaterial and construct two indicators: the Material Assurance Ratio and the Immaterial Assurance Ratio. We analyze their relationships with green patenting, environmental performance, institutional investor behavior, and analyst forecast accuracy. Firms with higher material assurance ratios show stronger sustainability outcomes—more green and CO2-related patents, lower resource use, and greater institutional investor trust. In contrast, higher immaterial assurance ratios are linked to weaker sustainability performance and reduced appeal to socially responsible investors. While ESG assurance improves analyst forecast accuracy overall, markets have yet to fully consider assurance content. These findings emphasize that assurance on material ESG issues signals genuine sustainability commitment, whereas immaterial assurance may reflect symbolic actions—highlighting the need for improved standards and investor awareness.
