MOSL manages changes to the Market Arrangements Code (MAC) and Wholesale Retail Code (WRC) on behalf of the non-household market. Changes can be proposed by any industry participant and MOSL supports proposers to design and develop proposals prior to Panel review and Ofwat determination whether to implement the proposal. This page provides information on current changes, how to engage with the change process and how to propose new changes.

MOSL prepares a change report for the Panel each month describing the progress of each change proposal and the anticipated implementation programme.  The current change report can be downloaded from the link on the right.  Previous reports can be downloaded in the Panel papers.

MOSL may consult on behalf of the Panel to gather evidence on the need for and impact of a change proposal. Input from market participants and customers is welcomed and live consultations can be accessed through the link on the right.

If you wish to raise a change please follow the link on the right which provides templates and contact details to submit changes.

The Change Register below shows all proposals that have been formally submitted to change the Market Arrangements Code (prefixed CPM) or Wholesale Retail Code (prefixed CPW). Please use the filter and sort functions to navigate past and current changes and click on a change to view the documents associated with it.

Change Register

Reference Title Status Implementation date
CPW083 Vacancy Incentive Scheme Implemented 15/05/2020
CPW084 Introducing a Retailer Measure of Experience (R-MeX). Implemented 01/04/2020
CPW087 Ability for Wholesalers to add meter reads Implemented 06/11/2020
CPW089 T101 Adding Billing Address fields Implemented 14/05/2021
CPW091 Temporary Changes to Vacancy Implemented 30/03/2020
CPW092/CPM029 Unified Disputes Process and Committee Implemented 13/11/2020
CPW093 Payment deferral interim measures Implemented 30/03/2020
CPW094 Temporary Change to Disconnections Implemented 08/04/2020
CPW095 Urgent: Maintain Credit Requirements Implemented 16/04/2020
CPW096 Urgent: Payment Deferral Medium Term Implemented 01/05/2020
CPW099 Clarify the responsibilities of Trading Parties during a planned event Implemented 14/05/2021
CPW101/CPM031 Unwinding Temporary Covid-19 Arrangements in the Business Retail Market Implemented 01/08/2020
CPW102/CPM030 Gender Neutrality in the Market Codes Implemented 06/11/2020
CPW103/CPM032 Interim Supply Process Amendments Implemented 09/09/2020
CPW104 Housekeeping changes to facilitate the Performance Regime introduced in April 2020 Implemented 15/02/2021

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