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
CPW107 Covid-19 Temporary Vacancy exemptions for Credit Support Implemented 23/10/2020
CPW108 Agreement to Unplanned Settlement Runs Implemented 26/01/2021
CPW111 Housekeeping change to align the codes with CMOS Implemented 14/05/2021
CPW112 Clarifications to CSD 0102 and CSD 0105 Implemented 14/05/2021
CPW113 Housekeeping Changes to Correct Typographical Errors and Enhance Standardisation Implemented 14/05/2021
CPW114/CPM037 Housekeeping Changes to Correct Typographical Errors and Enhance Standardisation Implemented 14/05/2021
ICP/WRC003 Alignment with Exit Regulations Implemented 02/10/2017
ICP/WRC036 Data Format Updates Implemented 02/10/2017
ICP/WRC048 Tariff Table Updates Implemented 02/10/2017
ICP/WRC051 Performance Charge Alignment with ISA Implemented 02/10/2017
ICP/WRC053 SPID Pairing Updates Implemented 02/10/2017
ICP/WRC055 Trade Effluent Updates - SVAM Subtract and Calculated Discharge Frequency Implemented 02/10/2017
ICP/WRC059 Settlement Updates Implemented 02/10/2017
CPM001 Change Proposal Form Update Implemented 03/07/2017
CPM003 Revised MIMP Committee Composition Implemented 01/12/2017

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