PartySubID (FIX tag 523)

StringFIX 4.4FIX 5.0 SP2

PartySubID (tag 523) is a String field defined in FIX 4.4 and FIX 5.0 SP2. It appears in 44 message types, always optionally.

At a glance

Tag: 523
Name: PartySubID
Datatype: String
Dialects: FIX 4.4 and FIX 5.0 SP2
Messages: 44

What the specification says

Sub-identifier (e.g. Clearing Account for PartyRole (452)=Clearing Firm, Locate ID # for PartyRole=Locate/Lending Firm, etc). Not required when using PartyID (448), PartyIDSource (447), and PartyRole.

Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.

A real message using tag 523

NewOrderSingle · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	159
35	MsgType	D	Order – Single
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
11	ClOrdID	ORD-10042
453	NoPartyIDs1 entry	1	repeating group
448	PartyID	EXAMPLE
802	NoPartySubIDs2 entries	2	repeating group
523	PartySubID	EXAMPLE
523	PartySubID	EXAMPLE
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	195

Edit and decode it yourself

Shown with | separators for readability. On the wire FIX uses SOH (0x01), an invisible control byte — and because BodyLength and CheckSum are computed over the actual bytes, the two forms have different checksums. Both are valid and both decode here.

Open in the full decoder →

Generated from the FIX 4.4 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 523 appears

Requiredness is a property of the message, not of the field: the same tag can be optional in one message and conditionally required in another.

Message	MsgType	FIX 4.4	FIX 5.0 SP2	Where in the message
AdjustedPositionReport	BL	—	Optional	inside Parties › PtysSubGrp
AllocationInstruction	J	Optional	Optional	inside Parties › PtysSubGrp
AllocationInstructionAck	P	Optional	Optional	inside Parties › PtysSubGrp
AllocationInstructionAlert	BM	—	Optional	inside Parties › PtysSubGrp
AllocationReport	AS	Optional	Optional	inside Parties › PtysSubGrp
AllocationReportAck	AT	Optional	Optional	inside Parties › PtysSubGrp
ApplicationMessageRequest	BW	—	Optional	inside Parties › PtysSubGrp
ApplicationMessageRequestAck	BX	—	Optional	inside Parties › PtysSubGrp
AssignmentReport	AW	Optional	Optional	inside Parties › PtysSubGrp
CollateralAssignment	AY	Optional	Optional	inside Parties › PtysSubGrp
CollateralInquiry	BB	Optional	Optional	inside Parties › PtysSubGrp
CollateralInquiryAck	BG	Optional	Optional	inside Parties › PtysSubGrp
CollateralReport	BA	Optional	Optional	inside Parties › PtysSubGrp
CollateralRequest	AX	Optional	Optional	inside Parties › PtysSubGrp
CollateralResponse	AZ	Optional	Optional	inside Parties › PtysSubGrp
Confirmation	AK	Optional	Optional	inside Parties › PtysSubGrp
ContraryIntentionReport	BO	—	Optional	inside Parties › PtysSubGrp
CrossOrderCancelReplaceRequest	t	Optional	Optional	inside SideCrossOrdModGrp › Parties › PtysSubGrp
CrossOrderCancelRequest	u	Optional	Optional	inside SideCrossOrdCxlGrp › Parties › PtysSubGrp
ExecutionReport	8	Optional	Optional	inside Parties › PtysSubGrp
IOI	6	—	Optional	inside Parties › PtysSubGrp
ListCancelRequest	K	—	Optional	inside Parties › PtysSubGrp
MarketDataIncrementalRefresh	X	—	Optional	inside MDIncGrp › Parties › PtysSubGrp
MarketDataRequest	V	—	Optional	inside Parties › PtysSubGrp
MarketDataRequestReject	Y	—	Optional	inside Parties › PtysSubGrp
MarketDataSnapshotFullRefresh	W	—	Optional	inside MDFullGrp › Parties › PtysSubGrp
MassQuote	i	Optional	Optional	inside Parties › PtysSubGrp
MassQuoteAcknowledgement	b	Optional	Optional	inside Parties › PtysSubGrp
MultilegOrderCancelReplace	AC	Optional	Optional	inside Parties › PtysSubGrp
NewOrderCross	s	Optional	Optional	inside SideCrossOrdModGrp › Parties › PtysSubGrp
NewOrderList	E	Optional	Optional	inside ListOrdGrp › Parties › PtysSubGrp
NewOrderMultileg	AB	Optional	Optional	inside Parties › PtysSubGrp
NewOrderSingle	D	Optional	Optional	inside Parties › PtysSubGrp
OrderCancelReplaceRequest	G	Optional	Optional	inside Parties › PtysSubGrp
OrderCancelRequest	F	Optional	Optional	inside Parties › PtysSubGrp
OrderMassActionReport	BZ	—	Optional	inside Parties › PtysSubGrp
OrderMassActionRequest	CA	—	Optional	inside Parties › PtysSubGrp
OrderMassCancelReport	r	—	Optional	inside Parties › PtysSubGrp
OrderMassCancelRequest	q	—	Optional	inside Parties › PtysSubGrp
OrderMassStatusRequest	AF	Optional	Optional	inside Parties › PtysSubGrp
OrderStatusRequest	H	Optional	Optional	inside Parties › PtysSubGrp
PositionMaintenanceReport	AM	Optional	Optional	inside Parties › PtysSubGrp
PositionMaintenanceRequest	AL	Optional	Optional	inside Parties › PtysSubGrp
PositionReport	AP	Optional	Optional	inside Parties › PtysSubGrp
Quote	S	Optional	Optional	inside Parties › PtysSubGrp
QuoteCancel	Z	Optional	Optional	inside Parties › PtysSubGrp
QuoteRequest	R	Optional	Optional	inside QuotReqGrp › Parties › PtysSubGrp
QuoteRequestReject	AG	Optional	Optional	inside QuotReqRjctGrp › Parties › PtysSubGrp
QuoteResponse	AJ	Optional	Optional	inside Parties › PtysSubGrp
QuoteStatusReport	AI	Optional	Optional	inside Parties › PtysSubGrp
QuoteStatusRequest	a	Optional	Optional	inside Parties › PtysSubGrp
RFQRequest	AH	—	Optional	inside Parties › PtysSubGrp
RegistrationInstructions	o	Optional	Optional	inside Parties › PtysSubGrp
RegistrationInstructionsResponse	p	Optional	Optional	inside Parties › PtysSubGrp
RequestForPositions	AN	Optional	Optional	inside Parties › PtysSubGrp
RequestForPositionsAck	AO	Optional	Optional	inside Parties › PtysSubGrp
SettlementInstructionRequest	AV	Optional	Optional	inside Parties › PtysSubGrp
SettlementInstructions	T	Optional	Optional	inside SettlInstGrp › Parties › PtysSubGrp
SettlementObligationReport	BQ	—	Optional	inside SettlObligationInstructions › Parties › PtysSubGrp
StreamAssignmentReport	CD	—	Optional	inside StrmAsgnRptGrp › Parties › PtysSubGrp
StreamAssignmentRequest	CC	—	Optional	inside StrmAsgnReqGrp › Parties › PtysSubGrp
TradeCaptureReport	AE	Optional	Optional	inside TrdCapRptSideGrp › Parties › PtysSubGrp
TradeCaptureReportAck	AR	—	Optional	inside TrdCapRptAckSideGrp › Parties › PtysSubGrp
TradeCaptureReportRequest	AD	Optional	Optional	inside Parties › PtysSubGrp

Wire format

Free-form text. Any byte except the SOH separator is legal, so values are not trimmed or case-folded on the wire. @boarteam/fix keeps the value as a string; format rules are checked by validate(), which reports validate/invalid-value rather than throwing.

Read tag 523 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix44";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const field = message.fields[523];field?.name;   // "PartySubID"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a string

Decode this in your own code

The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.

npm i @boarteam/fix @boarteam/fix-dict-fix44

Try the decoder Source on GitHub