Market Codes

This page contains the latest versions of the market codes, alongside guidance documents on industry processes, changes to the codes and consultations.

Governing the Market

The codes that govern the non-household retail market are the Market Arrangements Code (MAC) and the Wholesale Retail Code (WRC). The MAC is a non-statutory code established by licence conditions set out by Ofwat. The WRC is a statutory code forming the agreement entered into by wholesalers with those retailers they are providing services to.

The codes and any changes to them are approved by Ofwat and maintained by MOSL. If you have any queries on the market codes, please contact codechange@mosl.co.uk.

Key documentation

The Market Codes Structural Outline sets out the structure of the Market Codes framework, made up of the Market Codes and their associated documents. This document is owned by the Strategic Panel and is reviewed by the Strategic Panel as required.

The Baseline Statement lists the current versions of all market codes framework documents along with training, guidance, and policy documents. It includes their current version, updates, change process and ownership. The Baseline Statement is owned by MOSL and updated with each release of the Market Codes or supporting documents.

Market Codes

Name

1.0 Market Arrangements Code

Version
Effective from date

16th February 2024

18th December 2023

22nd May 2023

3rd March 2023

1st March 2022

14th January 2022

17th November 2021

5th November 2021

22nd September 2021

1st September 2021

14th May 2021

1st February 2021

28th January 2021

13th November 2020

6th November 2020

7th October 2020

9th September 2020

1st September 2020

28th August 2020

1st August 2020

1st July 2020

1st June 2020

8th April 2020

1st April 2020

23rd March 2020

1st January 2020

20th September 2019

23rd August 2019

26th July 2019

1st April 2019

29th March 2019

31st July 2018

30th March 2018

16th March 2018

1st December 2017

15th September 2017

17th July 2017

1st April 2017

Name

2.0 Schedule 1 Terms and Conditions of a Wholesale Contract

Version
Effective from date

22nd September 2021

1st April 2017

Name

2.1 Schedule 1 Part 1 Objectives, Principles and Definitions

Version
Effective from date

18th December 2023

27th October 2023

20th June 2023

29th November 2022

2nd August 2022

1st March 2022

5th November 2021

22nd September 2021

1st September 2021

26th January 2021

13th November 2020

6th November 2020

23rd October 2020

9th September 2020

28th August 2020

1st August 2020

15th May 2020

1st May 2020

1st April 2020

1st April 2020

7th November 2019

30th September 2019

26th July 2019

29th March 2019

31st January 2019

31st July 2018

3rd July 2017

1st April 2017

Name

2.2 Schedule 1 Part 2 Business Terms

Version
Effective from date

16th February 2024

7th April 2023

26th August 2022

2nd August 2022

5th November 2021

22nd September 2021

1st September 2021

14th May 2021

13th November 2020

6th November 2020

23rd October 2020

5th August 2020

1st August 2020

1st May 2020

16th April 2020

1st April 2020

30th March 2020

14th February 2020

30th September 2019

29th March 2019

28th February 2019

31st January 2019

31st July 2018

23rd April 2018

30th March 2018

14th July 2017

1st April 2017

Name

2.3 Schedule 1 Part 3 Operational Terms

Version
Effective from date

12th December 2023

27th September 2023

20th June 2023

29th November 2022

2nd August 2022

31st May 2022

2nd February 2022

22nd September 2021

1st September 2021

14th May 2021

9th September 2020

28th August 2020

15th May 2020

8th April 2020

1st April 2020

26th July 2019

1st April 2019

28th September 2018

3rd March 2018

1st December 2017

3rd July 2017

1st April 2017

Name

2.4 Schedule 1 Part 4 Market Terms

Version
Effective from date

18th December 2023

29th November 2022

26th August 2022

1st March 2022

22nd September 2021

14th May 2021

26th January 2021

13th November 2020

6th November 2020

9th September 2020

1st April 2020

14th February 2020

28th February 2019

3rd December 2018

28th September 2018

31st August 2018

18th May 2018

1st April 2017

Name

Annex E - process diagrams

Version
Effective from date

1st April 2017

Name

CSD 0001 - Market Entry Assurance and Market Re-assurance

Version
Effective from date

29th November 2022

5th November 2021

22nd September 2021

12th March 2018

1st April 2017

Name

CSD 0002 - Market Performance Framework

Version
Effective from date

18th January 2024

18th December 2023

12th December 2023

27th September 2023

20th June 2023

29th November 2022

2nd August 2022

31st May 2022

2nd February 2022

22nd September 2021

14th May 2021

15th February 2021

9th September 2020

1st August 2020

1st July 2020

1st June 2020

1st April 2020

23rd March 2020

1st November 2019

26th July 2019

1st April 2019

18th May 2018

29th March 2018

3rd March 2018

1st April 2017

Name

CSD 0003 - Volume Transfer and Volume Data Update

Version
Effective from date

2nd February 2022

22nd September 2021

1st April 2017

Name

CSD 0004 - Interim Supply Process

Version
Effective from date

27th October 2023

2nd February 2022

22nd September 2021

9th September 2020

1st April 2017

Name

CSD 0005 - Direction to Supply Allocation Process

Version
Effective from date

1st April 2017

Name

CSD 0006 - Trading Party Administration and Notification Processes

Version
Effective from date

20th June 2023

22nd September 2021

9th September 2020

3rd December 2018

26th October 2017

1st April 2017

Name

CSD 0007 - Business Continuity Management

Version
Effective from date

22nd September 2021

28th August 2020

29th March 2019

3rd December 2018

1st April 2017

Name

CSD 0101 - Registration: New Supply Points

Version
Effective from date

20th June 2023

14th May 2021

15th May 2020

26th October 2018

18th May 2018

29th March 2018

2nd October 2017

1st April 2017

Name

CSD 0102 - Registration: Transfers

Version
Effective from date

2nd February 2022

22nd September 2021

14th May 2021

15th February 2021

9th September 2020

7th November 2019

29th March 2019

26th October 2018

1st April 2017

Name

CSD 0103 - Registration: Cancellations and Erroneous Transfers

Version
Effective from date

20th June 2023

2nd February 2022

22nd September 2021

1st April 2017

Name

CSD 0104 - Maintain SPID Data

Version
Effective from date

29th November 2022

23rd October 2020

1st August 2020

30th March 2020

26th July 2019

17th May 2019

26th October 2018

2nd October 2017

1st April 2017

Name

CSD 0105 - Error Rectification and Retrospective Amendments

Version
Effective from date

19th July 2022

14th May 2021

7th November 2019

17th May 2019

29th March 2019

28th September 2018

2nd October 2017

1st April 2017

Name

CSD 0106 - Non-Market Meters

Version
Effective from date

1st April 2017

Name

CSD 0201 - Settlement Timetable and Reporting

Version
Effective from date

14th February 2020

31st August 2018

1st December 2017

1st April 2017

Name

CSD 0203 - Meter Read Submission: Validation

Version
Effective from date

12th May 2023

14th May 2021

15th February 2021

28th September 2018

1st April 2017

Name

CSD 0206 - Trade Effluent Processes

Version
Effective from date

29th November 2022

6th November 2020

26th July 2019

28th September 2018

1st April 2017

Name

CSD 0207 - Charge Calculation, Allocation and Aggregation

Version
Effective from date

29th November 2022

15th February 2021

14th February 2020

29th March 2019

1st April 2017

Name

CSD 0208 - Creation and update of Wholesaler Tariff Data

Version
Effective from date

17th May 2019

1st April 2017