Market Domain Data (MDD)

What is the market participant process?

The identity of market participants needs to be accurately known and managed for the gas industry to run efficiently.

As Central Data Service Provider (CDSP), we manage and maintain a list of all the identities of gas market participants. We call this the market participant process.

We store all names and ‘short codes’ in a document called the Market Domain Data (MDD) Market Participant identity list.

It’s our job to:

• verify and maintain the identities of all participants in the gas market
• enable participants to insert, change or delete their identities
• provide the MDD Market Participant identity list to people and organisations who need it

Who is it for?

You need to be included on the MDD Market Participant identity list if your organisation:

• is licenced
• needs to adhere to a gas industry code

And if you do these roles in the gas industry:

• Transporter – including Transmission Network Operators, Distribution Network Operators and Independent Gas Transporters
• Shipper
• Trader
• Supplier
• Meter Asset Manager (also known as Metering Equipment Managers in the Retail Energy Code and CSS messages)
• Meter Asset Provider
• Automated Meter Reading Service Provider (ASP)
• Smart Metering System Operator (SMSO)

What is the list used for?

It’s used to easily and accurately identify market participants in industry messages. This includes those processed by the Central Switching Service (CSS).

How to get your identity on the list

Once you have completed the market entry process you will be added to the next release of the MDD Market Participants list.

The Market Participant Identity Verification Approach document shows the rules we follow when validating your market entry application.

Our Join/exit the gas market webpage has more information.

How to change your listing?

You can apply to change, delete or create an end-date for your entry. Complete this form: Market Participant Change Process Form and email it to: xoserve.customer.lifecycle.team@xoserve.com.

MDD Market Participant identity list release schedule

This document shows the dates for when new lists are published: Market Participant ID Change Release Schedule 2025

MDD Market Participant list

Download the latest version of the MDD Market Participant list.

Archived MDD Market Participant lists

Below is an archive of previous MDD Market Participant list documents.