In 2019 the European Union (EU) Climate Benchmarks Regulation established a set of standardized emission reduction criteria for financial benchmarks. This study examines the risk-adjusted performance of equity exchange-traded funds (ETFs) tracking EU Climate Transition Benchmarks (CTBs) and EU Paris-Aligned Benchmarks (PABs). Our findings reveal that, after the implementation of the regulation, equity CTB ETFs have exhibited no significant risk-adjusted performance difference compared to their non-sustainable twin ETFs. Conversely, equity PAB ETFs, which adhere to more stringent environmental standards, have underperformed their non-sustainable counterparts. Our results suggest that stringent emission reduction objectives have a negative effect on investors’ returns.