ESMA published in October 2015 "Guidelines on Alternative Performance Measures". The guidelines are applicable for all listed companies and companies drawing up prospectuses when they report alternative performance measures in financial reports and prospectuses. The guidelines came into force on 3 July 2016. The Financial Supervisory Authority of Norway is responsible for monitoring the compliance with the guidelines in the Norwegian market.
In this regard ESMA has published a Q&A regarding the guidelines. The 6 New Q&A can be found on ESMA's webpage under the following link