In response to the United Nations' 2015 SDGs, Taiwan required in 2017 that companies with capital over NT$5 billion prepare CSR reports on Environmental, Social, and Governance (ESG) issues. This study analyzes the operational performance of 16 Taiwanese financial holding companies from 2016 to 2020 using Data Envelopment Analysis (DEA). Results show that companies perform better in economic and social aspects than in environmental ones, indicating room for improvement in sustainability practices. Applying advanced models, the study finds SinoPac, Taiwan, and Hua Nan Financial Holdings as the most efficient, while Yuanta, Jih Sun, and E. Sun are the least efficient. A truncated regression model reveals a significant negative relationship between operational scale, return on assets, and non-performing loan ratio with performance. Based on these findings, the study offers strategic recommendations for enhancing operational efficiency, particularly in environmental practices.