Financial institutions have a role in harmonising economic purposes with environmental and social purposes through transmission mechanisms whereby they provide channels to promote socially and environmental desirable activities. This study explores the sustainability criteria disclosed at firm-level corporate social responsibility reports for the purpose of providing direction for financial institutions committed to enhancing their contribution to sustainability objectives. The Delphi Method and the Decision-Making Trial and Evaluation Laboratory (DEMATEL) system have been employed to systematically analyse the opinions of 15 experts regarding the operation of the seven Taiwanese financial institutions listed on the Dow Jones Sustainability Index in 2019 with respect to their capacity to effect environmental sustainability objectives. The findings reveal a high prominence level for corporate governance, law compliance, risk management, occupational safety and health, representing amongst the sustainability criteria considered. This suggests that financial institutions may benefit from focusing resources into these areas, starting with corporate governance, when considering means for enhancing their sustainability performance. The study is limited by the small number of financial institution available in Taiwan which suggests that further research could be directed towards a wider sample of financial institutions, say by international comparison, expanding the range of industries studied, or the inclusion for additional sustainability indicators. Overall, the study has shed light on Taiwan’s financial institutions’ capacity to contribute to sustainable practices which is an area has not been extensively investigated below. This study may have useful implications for financial institutions in Taiwan. We also recognise other factors which are likely to contribute to social impacts. These include human capacity building and development, information security, green procurement, green building, and climate-related financial products. This study fills the gap by providing useful insights for a better understanding of sustainable development in financial institutions by promoting sustainability practice in general. The analysis will assist decision-makers in identifying and prioritising the driving factors and thus adopting suitable strategies to strengthen sustainability performance.