Transparency is a vital element for ensuring effective third party access and overall functioning of a competitive internal gas market. Regulation (EC) No 715/2009 includes a number of transparency requirements, going beyond those foreseen in the previous legislation. ACER is now examining the level of compliance of TSOs against these gas transparency requirements. An inquiry was opened since November 2011, with the cooperation of National Regulatory Authorities (NRAs) through the Gas Regional Initiative, and TSOs were asked to provide their own assessment of their level of compliance through Excel questionnaires. But in some cases, the assessment had to be carried out by NRAs. Ideally, the assessment of the level of compliance with transparency requirements should be checked and validated by NRAs as well as stakeholders. This is why, responses to the TSO questionnaires have been submitted to public consultation with stakeholders from the North-West and South gas Regions . In order to complete the public consultation process, ACER launched on 31 July a public consultation on Transparency in Gas Markets and is seeking stakeholder views on the TSO responses to the transparency questionnaire from the remaining countries, i.e. those which are not included in the North West and South gas Regions. A public workshop on Transparency in Gas Markets will be held in ACER premises in Ljubljana on 13 September 2012, in order to allow TSOs, NRAs and other stakeholders to express their views and provide their feedback to ACER before the final results are presented in the 22nd Madrid Forum in October 2012. TSOs, NRAs and stakeholders from all Member States, including the North West and South regions, are welcome to participate.