Self-Trade Prevention

2020-04-01

Self-Trade Prevention
Introduction
This document explains the functionality of and access to the optional self-trade prevention featureof Japannext PTS trading services. It describes trading service's configuration and usage ofapplication messages relevant to self-trade prevention.
Order entry protocol specifications are available from our website: http://en.japannext.co.jp/library.
For further information and inquiries please send an email to: ito@japannext.co.jp.

Overview
The self-trade prevention feature is intended to prevent orders with the same Market Participant
Identifier (MPID) from executing against one another. Trading venues make use of various
mechanisms to avoid self-trading. The mechanisms supported at Japannext PTS are:•Cancel newest•

Cancel oldest•

Decrement

Orders which are canceled or replaced due to self-trade prevention will be flagged with a protocol
specific reason.

Service Configuration
Self-trade prevention at Japannext PTS is configured on a per MPID basis and is available for allorder entry protocols. An MPID is an unique numeric identifier assigned by Japannext to the client.
Clients should specify an assigned MPID on entry of orders which should be subjected to self-trade
prevention. It is possible to use different MPIDs on a single order entry port.
To obtain an MPID clients must submit an application to Japannext. Additional MPIDs can berequested. An order entry port must be configured with the MPIDs intended to be used.

Functionality
Cancel Newest
Whenever an incoming order would execute against a resting order with the same MPID, theremaining balance of the incoming order will be canceled back to its owner.
Example:An order with MPID A enters to buy 1200 shares at a price of 100.1.
Match Incoming
Step Buy Order
Balance

Matching Sell
OrdersOrder

Action

MPID

1

1200

100@100

B

Executed 100 shares

21100

200@100.1 C

Executed 200 sharesSelf-Trade Prevention
Match Incoming
Step Buy Order
Balance
3900

Matching Sell
OrdersOrder
200@100.1

2020-04-01
ActionMPID
A

500@100.1 D

Canceled back 900 shares to buy order owner
200 shares remain on sell side
500 shares remain on sell side

Cancel Oldest
Whenever an incoming order would execute against a resting order with the same MPID, theremaining balance of the resting order will be canceled back to its owner. Attempted entry of theincoming order will then be resumed.
Example:An order with MPID A enters to buy 1200 shares at a price of 100.1.
Match Incoming
Step Buy Order
Balance

Matching Sell
OrdersOrder

Action

MPID

1

1200

100@100

B

Executed 100 shares

21100

200@100.1 C

Executed 200 shares

3900

200@100.1

Canceled back 200 shares to sell order owner

4900

500@100.1 D

5400

A

Executed 500 shares
Remaining 400 shares posted on buy sideDecrement
Whenever an incoming order would execute against a resting order with the same MPID, if bothorders are of the same size then they both will be canceled back to their owners, otherwise thesmaller order will be canceled back and the larger order decremented by the size of the smallerorder. Attempted entry of the incoming order will then be resumed.
Example:An order with MPID A enters to buy 1200 shares at a price of 100.1.
Match Incoming
Step Buy Order
Balance

Matching Sell
OrdersOrder

Action

MPID

1

1200

100@100

B

Executed 100 shares

21100

200@100.1 C

Executed 200 shares

3900

200@100.1

Canceled back 200 shares to sell order owner
Decremented 200 shares from buy order4700

500@100.1 D

5200A

Executed 500 shares
Remaining 200 shares posted on buy sideSelf-Trade Prevention

2020-04-01

Usage
OUCH Order Entry
Clients should set the Firm field of the Enter Order Message to an issued MPID. The specified
value will be reported in the Accepted Message.
In case of self-trade prevention, a Canceled Message with the Reason field set to M (Order expired
during match) will be sent to the order owner. Optionally clients may apply to instead receive anAIQ Canceled Message with specifics of the prevented trade.
If the specified MPID is not permitted on the port, a Rejected Message with the Reason field set toL (MPID not allowed for this port) will be sent.

FIX Order Entry
Clients should set the ClientID (109) field of the New Order Single message to an issued MPID.
The specified value will be reported in the Execution Report – Order Accepted message.
In case of self-trade prevention, an Execution Report – Order Canceled or Order Replaced message
with the ExecRestatementReason (378) field set to 100 (Trade prevention) will be sent to the orderowner.
If the specified MPID is not permitted on the port, an Execution Report – Order Rejected message
with the OrdRejReason (103) field set to 99 (Other) will be sent.

FIX Drop Copy
Copies of Execution Report – Order Canceled and Order Replaced messages due to self-trade
prevention will be reported downstream with the ExecRestatementReason (378) field set to 100(Trade prevention).