9 August 2007

Service Announcement

Trading, Infolect and CDS

Amendments to dynamic tick size bands in operation

- Advance Notification

The purpose of this Service Announcement is to inform you that there will be amendments to the dynamic price format code (“tick size”) schedules applied to nine trading segments. Dynamic tick refers to the automatic price sensitive system that determines the level of granularity that can be used according to the price of the incoming order or quote.

Service Announcement Live N32/07 was issued on 11 May 2007 and set out the dynamic tick bands that have been in operation since 18 June 2007, following the introduction of TradElect™.

As a result of recent market feedback the following changes are going to be made:

  • a new schedule will be introduced for quote driven US Dollar (USD), Euro (EUR) and GB Pounds (GBP) securities. Please note that GB Pence (GBX) securities will not be amended.
  • the existing International Order Book and International Bulletin Board security schedules will be revised.

Quote driven changes

Below is the new table for trading segments SEAQ, SEQ1, SEQ2, AIM, AIMI, AIM3, IRSQ, IRSU for currencies GBP / USD / EUR. Changes are indicated in blue.

Range / Price Format Code / Price Format Description / Price Format Value
Less than 1(changed from 10) / Z / One ten thousandth / 0.0001
More than 1 less than 100 (new band) / J / Hundredths / 0.01
100 or more (changed from 10) / Q / Quarters / 0.25

International Order Book and International Bulletin Board changes

Below is the revised table for trading segmentsIOB, IOBU, ITBB, ITBU for all current trading currencies (GBX / GBP / USD / EUR / AUD /CAD / DKK / HKD / INR / JPY / MYR / NOK / ZAR / ZWD ). Again changes are indicated in blue.

Range / Price Format Code / Price Format Description / Price Format Value
Less than1
(changed from 5) / L / One four-hundredth / 0.0025
1– 49.99
(changed from 5) / J / One hundredth / 0.01
50 – 99.9 / X / One tenth / 0.10
100 - 499.75 / Q / Quarters / 0.25
500 – 999.5
(new band) / H / Halves / 0.5
More than 1000
(new band) / W / Wholes / 1

Proposed schedule for introduction

CDS Tuesday 28August 2007

TradElect™ Monday 3 September 2007

Full Dynamic schedule

Appendix 1 sets out the full revised dynamic tick schedule as it applies to all trading segments.

Administration

Customer Development Service (CDS)

Customers are advised to subscribe to the CDS Service Channels S04, S08 and S12 for either the Reference Data Changes service on Friday 24August 2007or the Full Reference Data Download Service on Tuesday 28August 2007.

TradElect™

Customers are advised to subscribe to the CDS Service Channels S04, S08 and S12 for either the Reference Data Changes serviceon Friday 31August 2007 or the Full Reference Data Download Service on Monday 3 September 2007.

Additional Information

Should you have any general queries about this announcement, please contact your primary account manager at the Exchange.

Alternatively if the enquiry is regulatory or technical please use the telephone numbers set out below:

  • Market Supervision: +44 (0)20 7797 3666 - option 1
  • Technical Information:+44 (0)20 7797 3939.

An archive of previously issued announcements is available in the “Technical Library” section of the Exchange's corporate website

(

Service Announcement (Live)58/07

Page 1 of 3

London Stock Exchange plc Registered in EnglandWales No 2075721