1. Market Data Optimisation 2009 (MDO) Phase II 14 May 2009 A consultation

2. 2 MDO 2009 Phase II - Introduction Following the success of Market Data Optimisation 2009, the Group is initiating on a second phase of the project, which aims to deliver further enhancements and a more diverse distribution of instruments across channels. The existing structure of both London and Milan channels will be further refined to allow an increase in the simulatenous publication of messages across a wider range of multicast channels, as well as deliver a number of optimisations driven directly by customer feedback. MDO Phase II will deliver the following benefits: Improvements in the parallel distribution of real time messages – an increased number of channels for UK and Borsa data Streamlined processing path from TradElect to Infolect Optimised channel configurations, ensuring a consistent delivery approach across all markets and services – see slide 3 for more details

3. 3 MDO 2009 Phase II - Scope Key scope items of MDO Phase II are: Additional load balancing of instruments across both London and Milan channels Reduction in idle poll interval from 15 to 5 seconds, Transfer of all Covered Warrants market data messages (some ‘added value’ and ‘trade reports’ message types) to appropriate Covered Warrants Service/Performance Channels, Rename of Px3 channels to Px2 to mirror Service Channel structure, Decommissioning of the following legacy Level 1 Plus messages: — 5AB Return Measures — 5MV Market Share Top 5 — 5AF Alpha/Betas — 5AP Average Cumulative Volumes, Decommissioning of the 5UP Uncrossing Price message from the Level 2 channels. Target go-live date: September 2009

4. 4 UK Markets: Additional Load Balancing Impact Channel Structure - Existing S/PaxSETS: FTSE 100 > 1% S/PbxSETS: FTSE 100 < 1% S/PcxSETS: FTSE 250 1 S/PdxSETS: FTSE 250 2 S/PexETFs, ETCs & Specialists S/PfxSETS, SETSqx, SEAQ, IRS & Misc. S/PgxReserved for future use S/PhxReserved for future use S/PixReserved for future use S/PjxReserved for future use Channel Structure Post MDO Phase II S/PaxUK Instruments - Group 1 S/PbxUK Instruments – Group 2 S/PcxUK Instruments – Group 3 S/PdxUK Instruments – Group 4 S/PexUK Instruments – Group 5 S/PfxUK Instruments – Group 6 S/PgxUK Instruments – Group 7 S/PhxUK Instruments – Group 8 S/PixUK Instruments – Group 9 S/PjxUK Instruments – Group 10 S/PkxUK Instruments – Group 11 S/PlxUK Instruments – Group 12 S/PmxReserved for future use S/PnxReserved for future use S/PoxReserved for future use S/PpxReserved for future use S/PqxReserved for future use S/PrxReserved for future use The existing range of UK channels will be further distributed across 12 channels for each Level of data. Instruments within this product set will be balanced evenly across all of the channels. The Exchange will publish a list detailing which instruments will be sent on each channel. As and when instruments move channels, a revised list will be available. These changes will affect all data channels – see slide 4. The same approach will be adopted for the current and future Borsa Italiana data channels – see slide 6.

5. 5 UK Markets: Additional Load Balancing Impact(2) The remaining channels will have their Service Codes and multicast IP addresses updated to be contiguous. Channel Structure Post MDO Phase II (Cont‘d) S/P03 UK Reference Data S/P04 International Level 1 S/P05 International Level 2 S/P06 International Reference Data S/P07 European Level 1 S/P08 European Level 2 S/P09 European Reference Data S/P10 Covered Warrants Level 1 S/P11 Covered Warrants Level 2 S/P12 Market Status Indicators S/P13 Market Reference Data S/P14 RNS News S/P15 DOL (Full) S/P16 DOL Changes

6. 6 Borsa Markets: Additional Load Balancing Impact Structure Post Affari Phase II D01Italian - Level 1 D02Reserved for future use D03Italian - Level 2 Depth D04Italian Reference Data D05Market Status Indicators (Borsa) D06Market Reference Data D07SEDEX – Level 1 D08SEDEX – Level 2 Depth D09SEDEX Reference Data D10MOT – Level 1 D11MOT – Level 2 Depth D12MOT Reference Data D13ETF Plus – Level 1 D14ETF Plus - Level 2 Depth D15ETF Plus Reference Data Structure Post MDO Phase II D01MTA & Expandi Instruments – Level 1 – Group 1D22SEDEX Reference Data D02MTA & Expandi Instruments – Level 1 – Group 2D23MOT Instruments – Level 1 – Group 1 D03MTA & Expandi Instruments – Level 1 – Group 3D24MOT Instruments – Level 1 – Group 2 D04Reserved for future useD25Reserved for future use D05Reserved for future useD26Reserved for future use D06Reserved for future useD27MOT Instruments – Level 2 – Group 1 D07MTA & Expandi Instruments – Level 2 – Group 1D28MOT Instruments – Level 2 – Group 2 D08MTA & Expandi Instruments – Level 2 – Group 2D29Reserved for future use D09MTA & Expandi Instruments – Level 2 – Group 3D30Reserved for future use D10Reserved for future useD31MOT Reference Data D11Reserved for future useD32ETF Plus Instruments – Level 1 – Group 1 D12Reserved for future useD33ETF Plus Instruments – Level 1 – Group 2 D13MTA & Expandi Instruments Reference DataD34Reserved for future use D14SEDEX Instruments – Level 1 – Group 1D35Reserved for future use D15SEDEX Instruments – Level 1 – Group 2D36ETF Plus Instruments – Level 2 – Group 1 D16Reserved for future useD37ETF Plus Instruments – Level 2 – Group 2 D17Reserved for future useD38Reserved for future use D18SEDEX Instruments – Level 2 – Group 1D39Reserved for future use D19SEDEX Instruments – Level 2 – Group 2D40ETF Plus Instruments Reference Data D20Reserved for future useD41Market Status Indicators (Borsa) D21Reserved for future useD42Market Reference Data

7. 7 We welcome your feedback on the proposed changes. If you have any questions or comments please send them to us via your Technical Account Manager, or by emailing: infolect@londonstockexchange.com infolect@londonstockexchange.com Feedback