Green bonds — debt taken on to finance projects with environmental benefits — hit a record last month with $50 billion issued, as more and more companies and governments turn to the instruments.

Adidas, French electricity firm EDF and telecoms firm Orange, along with the nations of Germany, Egypt and Sweden all issued green bonds in September, helping the volume jump by five times from August.

The value of green bonds issued so far this year climbed to more than $176 billion, a 26-percent increase from the same period in 2019.

The total includes instruments that meet the principles set out by the International Capital Market Association, the professional association that unites the global bond market and information compiled by Bloomberg.

The ICMA defines green bonds as those which finance renewable energy, energy efficiency, biodiversity, pollution reduction and other similar projects.

But as ECB executive board member Isabel Schnabel recently pointed out, green bonds remain a small fraction of the overall debt market, accounting for just five percent last year.

The September boom in green bonds is due in part to the fact that many operations were postponed earlier in the year due to the coronavirus pandemic. The volume of green bonds issued in the first half of 2020 dipped compared to the same period in 2019.

“This month, the volume of corporate green debt was more important than the volume of state green debt,” said Jovita Razauskaite, an expert on green bonds at asset manager NN Investment Partners.

The arrival of a major sovereign emitter has energised the market, with Germany making its first issue. The placement of 6.5 billion euros in September is to be followed by another of 5.0 billion before the end of the year.

“We expect a more diversified issuer base,” said Razauskaite.

“In particular,