Green bonds are seen as a key instrument to unlock climate finance. While their volume has grown steadily in recent years, the impact of the ‘green’ label on the bond market is poorly understood. Here, we investigate the differences between the yield term structures of green and conventional bonds in the US municipal bond market. We show that, although returns on conventional bonds are on average higher than for green bonds, the differences can largely be explained by the fundamental properties of the bonds. Historically, green bonds have been penalized on the municipal market, being traded at lower prices and higher yields than expected by their credit profiles. In recent years, however, the credit quality of municipal green bonds has increased and the premium turned positive. Green bonds are thus becoming an increasingly attractive investment, with scope to bridge the climate finance gap for mitigation and adaptation.

绿色债券被视为释放气候​​资金的关键工具。尽管近年来它们的数量稳定增长，但人们对“绿色”标签对债券市场的影响知之甚少。在这里，我们研究了美国市政债券市场中绿色债券与传统债券的收益期限结构之间的差异。我们表明，尽管常规债券的收益平均高于绿色债券，但差异在很大程度上可以由债券的基本性质来解释。从历史上看，绿色债券在市政市场上受到惩罚，其价格和收益率高于其信用状况所预期的价格。然而，近年来，市政绿色债券的信用质量有所提高，溢价也转为正数。因此，绿色债券正成为越来越具有吸引力的投资，