MIT201 – GUIDE TO THE TRADING SYSTEM

MIT201 – GUIDE TO THE TRADING SYSTEM

1.0 Introduction
London Stock Exchange is committed to continually enhancing its markets. UK cash equity markets migrated to 
MillenniumIT’s multi-asset class, ultra-low latency platform, Millennium Exchange, on 14 February 2011.
Since that time we have continued to improve performance and launched new services such as Sponsored 
Access, providing non-members a direct technical connection to our order books under the trading codes of a 
sponsoring member firm and the Closing Price Crossing Session.
There have also been enhancements to the Request for Quote functionality which is now available for equities, 
exchange traded products (ETPs) and deposit receipts, traded on the SETS, ETPs – Euroclear Bank Settlement 
and International Order Book (IOB) trading services. This continues to be supported by pre-trade risk controls that 
are available for single connection trading customers. These have been specifically designed to help General 
Clearing Members facilitate smaller order book users, who in the past were unable to obtain cost effective access.
1.1 Purpose
The purpose of this document is to provide participants with:
A business overview of the Millennium Exchange trading system and the TRADEcho off-book trade reporting and 
SI quoting service
A high level, technical overview of the following areas:
• Customer facing trading interfaces to Millennium Exchange trading system (both FIX 5.0 and Native)
• Customer connectivity to TRADEcho
• Disaster recovery
Generic operation of the Trading Services provided by Millennium Exchange:
The detailed operation of each Trading Service is governed by the specific configuration of Millennium Exchange 
TRADEcho, which is summarised in the Millennium Exchange & TRADEcho Business Parameters Document 
(Business Parameters document). Both this document and the Business Parameters document should be read in 
conjunction with the Rules of the London Stock Exchange.
Technical details of the information system and the approach to customer testing are covered in the Technical 
Parameters document as well as the associated Technical Specifications and Release notes.
1.2 Relevant London Stock Exchange communication channels
Rules of the London Stock Exchange
The full current Rules of the London Stock Exchange in force can be found at:
www.londonstockexchange.com/resources/trade-resources?tab=rules-and-regulations
Changes to the Rules of the London Stock Exchange and other key regulatory announcements are made 
by London Stock Exchange notices.
Stock Exchange notices
To sign up to email notification of future London Stock Exchange notices and view the library of previous 
ones please see: www.londonstockexchange.com/resources/london-stock-exchange-notices?tab=2021
Service announcements
Live service changes and other trading and information product news is notified by service 
announcements. To be added to the service announcement distribution list, please email: 
msu@lseg.com.
To view the library of previous service announcements please see:
www.londonstockexchange.com/products-and-services/technical-library/service-announcements/serviceannouncements.htm

Live Service Portal
The current system status of London Stock Exchange’s services are displayed on its Live Service Portal. 
This is the mechanism for London Stock Exchange communicating any market intervention actions it 
takes as a result of a service interruption. Participants can register to receive both SMS text and email 
notification of status changes of the portal, which can be found at: http://liveservice.lseg.com
Trading Services webpage
More details of London Stock Exchange’s trading systems, including where the latest versions of this 
document and the Business Parameters document can be found:
www.londonstockexchange.com/tradingservices
Trading database tools
To help you keep your trading database synchronised on a real-time basis, you may wish to subscribe to either 
the Datasync Email Service or the Datasync Daily Tradable Instrument Report (DTI). To find out more please 
see:
www.lseg.com/areas-expertise/post-trade-services/matching-and-reconciliation/unavista-solutions/unavistadata-solutions/datasync
You can also subscribe to Corporate Action information at:
www.lseg.com/areas-expertise/post-trade-services/matching-and-reconciliation/unavista-solutions/unavistadata-solutions/corporate-actions
For both services please contact:
• STX: 33009
• Telephone: +44 (0)20 7797 3009
• Email: unavistadatasolutions@lseg.com
Member Portal
The Member Portal enables members to manage their member profile and technical configuration via a single 
online interface:
• Member information: company details and regulatory authorisation
• Market management: trading service access, identifiers, clearing and settlement configuration 
(London Stock Exchange)
• Technical configuration: configuration for production trading systems
• Compliance information: compliance contacts and registered persons for order deletion
• User management: manage user access and permissions
• Third-party clearing and settlement providers will also be able to use the Member Portal to support 
member trading configuration set-up
• Market making registrations
Visit: www.lseg.com/markets-products-and-services/our-markets/markets-membership/member-portal
1.3 Readership
This document outlines the Trading Services available on Millennium Exchange and TRADEcho. When read in 
conjunction with the message specifications it is intended that these documents provide the information that 
participants require to develop to these services.
This document is particularly relevant to trading, compliance and technical staff within London Stock Exchange’s 
member firms and software providers.

MIT201 – GUIDE TO THE TRADING SYSTEM