The Market Rules consist of the latest approved SEMOpx Rules, Operating Procedures and any approved Modifications which have not yet been incorporated into the main body of the Rules or the Operating Procedures.
Modifications process
Any change to the SEMOpx Rules and Operating Procedures are required to go through a Modification Process that is governed by and set out in the SEMO Exchange Committee Procedures.
Modifications in Effect on the Baseline
It is important to note that a Modification may become effective before the published draft of the Code is amended to include the Modification.
| Mod ID | Title | Mod Status | Stage | Section Affected | Effective Date | Publication Date |
|---|---|---|---|---|---|---|
| SPX_01_25 | SDAC 60Min Harmonised Reference Price | SEMOpx Decision: Approved | Active | Operating Procedure Appendix A | 30/09/2025 | |
| SPX_04_24 | Housekeeping Modification Proposal related to 30 min MTU | SEMOpx Decision: Approved | Active | Operating Procedure Appendix A, Operating Procedure Section A, Operating Procedure Section B, Operating Procedure Section C | 30/09/2025 | |
| SPX_03_24 | Multiple Auction Trading System (MATS) Implementation | RA Decision: Approved (Not Vetoed) | Active | Operating Procedure Appendix A, Operating Procedure Glossary, Operating Procedure Section A, Operating Procedure Section B, Operating Procedure Section C, Rules Glossary | 28/08/2025 | |
| SPX_01_24 | 30 Minute MTU Implementation in the Day-Ahead Market | SEMOpx Decision: Approved | Active | Operating Procedure Appendix A | 30/09/2025 |
SPX_01_25 SDAC 60Min Harmonised Reference Price.pdf
SEMOpxOperatingProceduresLegalDrafting-SPX_04_24.docx