The Bloomberg Barclays MSCI Green Bond Index was again voted best index, with one investor judge praising its role in helping "maintain the integrity of the market".

Another judge described it as: "Best in class, combining the leading fixed income work of Bloomberg/Barclays as index provider, and the leading environmental, social and governance index provider, in MSCI".

In a market in which there is no universally agreed definition of green, investors appreciate the index's clear criteria for green bond selection, combined with monitoring until a bond's proceeds have been fully dispersed, or for the life of the bond, whichever comes first.

For example, the index excludes large hydropower projects that do not meet its sustainability criteria – a project must achieve a score of more than three in its Hydropower Sustainability Assessment Protocol, or commit to meet eight IFC performance standards. It believes projects that fail to meet these criteria are likely to trigger negative environmental and social externalities.

Its green buildings criteria require a green certification or a demonstration of energy efficiency top performance. 

From the index's launch in 2014 to the end of 2017, some 13% of self-labelled green bonds which met size and currency criteria were excluded because they did not meet the green bond criteria. The most common grounds for exclusion related to the bond's use of proceeds.

For example, in 2017 it excluded a controversial green bond from Spanish oil & gas firm Repsol, the proceeds of which were to be used to improve the efficiency of its operations, making more than a million tonnes of carbon dioxide savings. Yet it failed to demonstrate enough evidence of meeting the index's energy efficiency criteria.

Another exclusion was Indian renewables firm Greenko, which failed to provide adequate information about its processes for developing hydropower projects.

BlackRock, in March 2017, launched a green bond fund tracking the Bloomberg Barclays MSCI Global Green Bond Index.  Meanwhile, MSCI said the index is often used as a "reference benchmark", with green bond issuers clarifying that they are aligned with its criteria in their roadshow presentations.