This paper examines the causal effects of ESG (Environment, Social, and Governance) rating and the usage of sustainable finance (i.e. green bond issuance) on firm productivity and innovation, using Korean data. It is thought ESG activities and green bond issuance may serve to signal the firm’s ability and subsequently attract further inward investment and resources to enhance its performance. In a similar vein, start-up value has been found to be correlated with various forms of potential signaling devices. Using KoPDP (Korea Patent Data Project) database, as well as the ESG ratings provided by Korea Corporate Governance Service (KCGS) and Bloomberg Green’s data on green bond issuance. This study will explore the role of ESG (both individual and overall) ratings and green bond issuance on firm-level innovation activities.