The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Alexander Monk currently works for Schroder Investment Management which has investments in green bonds and is a Member of ICMA's Green Bond Principles/Social Bond Principles. Note, Alexander Monk's work on the data collection, analysis and any results presented in the paper was completed prior to his employment with Schroder Investment Management, and the author has no current involvement with green bonds.