Outbound Messages#

Note on Terminology: This page uses official OUCH 5.0 terminology (exchange perspective). In this documentation, “Outbound Messages” means Exchange → Client. For client-perspective terminology (Egress/Ingress), see Terminology Glossary.

Outbound messages are sent from the OUCH host to the participant. They are sequenced and use guaranteed-delivery transport.

System Event Message (Type S)#

System Event — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘S’

System Event message type

Timestamp

1

8

Timestamp

Nanoseconds since midnight

Event Code

9

1

Alpha

S = Start of Day, E = End of Day

Order Accepted (Type A)#

Acknowledges receipt and acceptance of an Enter Order message.

Order Accepted — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘A’

Accepted message

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

UserRefNum of the accepted order

Side

13

1

Alpha

As entered

Quantity

14

4

Integer

Shares accepted

Symbol

18

8

Alpha

Stock symbol

Price

26

8

Price

Accepted price (may differ from entered)

Time In Force

34

1

Alpha

Accepted TIF

Display

35

1

Alpha

Y/N/A/Z

Order Reference Num

36

8

Numeric

NASDAQ-assigned day-unique identifier

Capacity

44

1

Alpha

A, P, R, O

Intermarket Sweep Elig

45

1

Alpha

Y/N

CrossType

46

1

Alpha

N/O/C/H/S/R/E/A

Order State

47

1

Alpha

L = Live, D = Dead

ClOrdID

48

14

Alpha

Customer order ID

Appendage Length

62

2

Integer

Length of optional fields

Optional Appendage

64

var

TagValue

See Note 1

Notes for Order Accepted#

  • Note 1 (Optional Appendage): Optional fields include: Firm, MinQty, CustomerType, MaxFloor, PriceType, PegOffset, DiscretionPrice, DiscretionPriceType, DiscretionPegOffset, PostOnly, RandomReserves, Route, ExpireTime, TradeNow, HandleInst, BBO Weight Indicator, GroupID, SharesLocated, UserRefIdx.

Order Replaced (Type U)#

Acknowledges a successful Replace Order request.

Order Replaced — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘U’

Replaced message

Timestamp

1

8

Timestamp

Nanoseconds since midnight

OrigUserRefNum

9

4

Numeric

UserRefNum of the original order

UserRefNum

13

4

Numeric

UserRefNum of the replacement order

Side

17

1

Alpha

As entered

Quantity

18

4

Integer

Shares outstanding after replace

Symbol

22

8

Alpha

Stock symbol

Price

30

8

Price

Accepted price

Time In Force

38

1

Alpha

Accepted TIF

Display

39

1

Alpha

Y/N/A/Z

Order Reference Num

40

8

Numeric

New NASDAQ order reference number

Capacity

48

1

Alpha

A/P/R/O

Intermarket Sweep Elig

49

1

Alpha

Y/N

CrossType

50

1

Alpha

N/O/C/H/S/R/E/A

Order State

51

1

Alpha

L = Live, D = Dead

ClOrdID

52

14

Alpha

Replacement customer ID

Appendage Length

66

2

Integer

Length of optional appendage

Optional Appendage

68

var

TagValue

See Note 1

Notes for Order Replaced#

  • Note 1 (Optional Appendage): Supported options: Firm, MinQty, MaxFloor, PriceType, PostOnly, ExpireTime, TradeNow, HandleInst, BBO Weight Indicator, UserRefIdx.

Order Canceled (Type C)#

Indicates an order was partially or fully canceled.

Order Canceled — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘C’

Order Canceled

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

UserRefNum of the order being canceled

Quantity

13

4

Numeric

Shares decremented (incremental)

Reason

17

1

Alpha

Cancel reason (see Appendix B)

Appendage Length

18

2

Integer

Optional

Optional Appendage

20

var

TagValue

See Note 1

Notes for Order Canceled#

  • Note 1 (Optional Appendage): Supported option: UserRefIdx.

AIQ Canceled (Type D)#

Indicates shares were canceled due to Automatic Internalization / Self-Match Prevention (SMP) rules.

AIQ Canceled — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘D’

AIQ Canceled

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Order affected

Decrement Shares

13

4

Numeric

Shares canceled (incremental)

Reason

17

1

Alpha

Always ‘Q’ for SMP

Quantity Prevented Trading

18

4

Integer

Shares that would have executed without SMP

Execution Price

22

8

Price

Price trade would have occurred at

Liquidity Flag

30

1

Alpha

See Appendix D

AIQ Strategy

31

1

Alpha

AIQ mode

Appendage Length

32

2

Integer

Optional

Optional Appendage

34

var

TagValue

Only UserRefIdx

Order Executed (Type E)#

Indicates an order execution (partial or full).

Order Executed — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘E’

Order Executed

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Order executed

Quantity

13

4

Numeric

Shares executed (incremental)

Price

17

8

Price

Execution price

Liquidity Flag

25

1

Alpha

See Appendix D

Match Number

26

8

Numeric

Unique trade match identifier

Appendage Length

34

2

Numeric

Optional

Optional Appendage

36

var

TagValue

Only UserRefIdx

Broken Trade (Type B)#

Indicates a previously reported execution was nullified.

Broken Trade — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘B’

Broken Trade

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Order whose execution was broken

Match Number

13

8

Numeric

Match number that is being broken

Reason

21

1

Alpha

Reason code

ClOrdID

22

14

Alpha

Customer identifier

Appendage Length

36

2

Integer

Optional

Optional Appendage

38

var

TagValue

Only UserRefIdx

Rejected (Type J)#

Indicates an order (Enter or Replace) was rejected.

Rejected — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘J’

Rejected

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Order being rejected

Reason

13

2

Numeric

Reject reason (see Appendix C)

ClOrdID

15

14

Alpha

Customer ID

Appendage Length

29

2

Integer

Optional

Optional Appendage

31

var

TagValue

Only UserRefIdx

Cancel Pending (Type P)#

Indicates a cancel request cannot be honored yet for a cross order during late period.

Cancel Pending — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘P’

Cancel Pending

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Affected order

Appendage Length

13

2

Integer

Optional

Optional Appendage

15

var

TagValue

Only UserRefIdx

Cancel Reject (Type I)#

Occurs when a partial cancel for a cross order during late period cannot be honored.

Cancel Reject — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘I’

Cancel Reject

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Affected order

Appendage Length

13

2

Integer

Optional

Optional Appendage

15

var

TagValue

Only UserRefIdx

Order Priority Update (Type T)#

Indicates NASDAQ changed an order’s priority.

Order Priority Update — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘T’

Order Priority Update

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Affected order

Price

13

8

Price

Updated limit price

Display

21

1

Alpha

New display flag

Order Reference Num

22

8

Numeric

New NASDAQ-assigned order ref number

Appendage Length

30

2

Integer

Optional

Optional Appendage

32

var

TagValue

Only UserRefIdx

Order Modified (Type M)#

Sent in response to a Modify Order request.

Order Modified — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘M’

Order Modified

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Modified order

Side

13

1

Alpha

Updated side

Quantity

14

4

Numeric

Outstanding shares

Appendage Length

18

2

Integer

Optional

Optional Appendage

20

var

TagValue

Allowed: UserRefIdx, SharesLocated, LocateBroker

Order Restated (Type R)#

Indicates NASDAQ modified an order for internal order-management reasons.

Order Restated — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘R’

Order Restated

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

Order being restated

Reason

13

1

Alpha

R = refresh display, P = update displayed price

Appendage Length

14

2

Integer

Optional

Optional Appendage

16

var

TagValue

See Note 1

Notes for Order Restated#

  • Note 1 (Optional Appendage): Supported fields: Display Quantity, Display Price, SecondaryOrdRefNum, UserRefIdx.

Mass Cancel Response (Type X)#

Acknowledges a valid Mass Cancel Request. All fields from the inbound request are echoed.

Mass Cancel Response — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘X’

Mass Cancel Response

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

UserRefNum from inbound request

Firm

13

4

Alpha

All caps; order-entry firm

Symbol

17

8

Alpha

Optional, space-filled

Appendage Length

25

2

Integer

Optional fields length

Optional Appendage

27

var

TagValue

Options: Side, Group ID, UserRefIdx

Disable Order Entry Response (Type G)#

Acknowledges a Disable Order Entry Request.

Disable Order Entry Response — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘G’

Disable Order Entry Response

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

UserRefNum from inbound message

Firm

13

4

Alpha

All caps

Appendage Length

17

2

Integer

Optional

Optional Appendage

19

var

TagValue

Only UserRefIdx

Enable Order Entry Response (Type K)#

Acknowledges an Enable Order Entry Request.

Enable Order Entry Response — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘K’

Enable Order Entry Response

Timestamp

1

8

Timestamp

Nanoseconds since midnight

UserRefNum

9

4

Numeric

UserRefNum from inbound request

Firm

13

4

Alpha

All caps

Appendage Length

17

2

Integer

Optional

Optional Appendage

19

var

TagValue

Only UserRefIdx

Account Query Response (Type Q)#

Response to an Account Query Request. Indicates the next usable UserRefNum.

Account Query Response — Field Specification#

Name

Offset

Length

Type

Notes

Type

0

1

‘Q’

Account Query Response

Timestamp

1

8

Timestamp

Nanoseconds since midnight

NextUserRefNum

9

4

Numeric

Next available UserRefNum

Appendage Length

13

2

Integer

Optional

Optional Appendage

15

var

TagValue

Only UserRefIdx