Since 1 March 2021, certification bodies and their respective auditors require formal authorisation in order to carry out the company audits of the requirements of the government-run certification label Green Button.

The suitability of the certification bodies and their auditors is checked in a two-stage procedure. Auditors receive further training on the topics of due diligence and the Green Button auditing process through an intensive and comprehensive training programme.

A new member since March 2021 is the assurance provider Hohenstein.
Another new member since May 2021 is the certification body Ceres.