Green bonds: Catalyst or constraint for corporate green investment efficiency?

Green bonds have emerged as a critical external financing channel for corporate green investments. However, focusing solely on the scale of investment without considering efficiency provides an incomplete understanding of the role of such bonds. This paper investigates the impact of green bonds on green investment efficiency (GIE) using the DEA-Malmquist model, incorporating undesirable outputs. It also explores the influencing factors and mechanisms underlying this relationship. The key findings include the following: (1) Green bonds enhance GIE primarily through improved technical efficiency rather than technological progress. The scale of green bonds has an inverted U-shape relationship with GIE. (2) The effect is more pronounced in firms with low agency costs, firms with limited government subsidies, state-owned enterprises, and firms in heavily polluting industries. (3) Green bonds contribute to GIE by bridging the gaps in internal green governance and amplifying external pressures, such as media attention. (4) A lag effect is observed, with benefits for pollution reduction and the efficiency of green technological innovation manifesting over time. These findings provide valuable insights into the role of green bonds, offering a dual perspective on their economic and environmental impacts while guiding policies and practices for sustainable corporate development.