TradingSessionSubID (FIX tag 625)

StringFIX 4.4

TradingSessionSubID (tag 625) is a String field defined in FIX 4.4. It appears in 51 message types, always optionally.

At a glance

Tag: 625
Name: TradingSessionSubID
Datatype: String
Dialects: FIX 4.4
Messages: 51

What the specification says

Optional market assigned sub identifier for a trading session. Usage is determined by market or counterparties. Used by US based futures markets to identify exchange specific execution time bracket codes as required by US market regulations.

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

A real message using tag 625

NewOrderSingle · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	165
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
386	NoTradingSessions2 entries	2	repeating group
336	TradingSessionID	REGULAR
625	TradingSessionSubID	EXAMPLE
336	TradingSessionID	REGULAR
625	TradingSessionSubID	EXAMPLE
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	176

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 625 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	Requiredness	Where in the message
Advertisement	7	Optional	directly on the message body
AllocationInstruction	J	Optional	directly on the message body
AllocationReport	AS	Optional	directly on the message body
BidRequest	k	Optional	inside the BidCompReqGrp component
BidResponse	l	Optional	inside the BidCompRspGrp component
CollateralAssignment	AY	Optional	directly on the message body
CollateralInquiry	BB	Optional	directly on the message body
CollateralInquiryAck	BG	Optional	directly on the message body
CollateralReport	BA	Optional	directly on the message body
CollateralRequest	AX	Optional	directly on the message body
CrossOrderCancelReplaceRequest	t	Optional	inside the TrdgSesGrp component
DerivativeSecurityList	AA	Optional	inside the RelSymDerivSecGrp component
DerivativeSecurityListRequest	z	Optional	directly on the message body
ExecutionReport	8	Optional	directly on the message body
MarketDataIncrementalRefresh	X	Optional	inside the MDIncGrp component
MarketDataRequest	V	Optional	inside the TrdgSesGrp component
MarketDataSnapshotFullRefresh	W	Optional	inside the MDFullGrp component
MassQuote	i	Optional	inside QuotSetGrp › QuotEntryGrp
MassQuoteAcknowledgement	b	Optional	inside QuotSetAckGrp › QuotEntryAckGrp
MultilegOrderCancelReplace	AC	Optional	inside the TrdgSesGrp component
NewOrderCross	s	Optional	inside the TrdgSesGrp component
NewOrderList	E	Optional	inside ListOrdGrp › TrdgSesGrp
NewOrderMultileg	AB	Optional	inside the TrdgSesGrp component
NewOrderSingle	D	Optional	inside the TrdgSesGrp component
OrderCancelReplaceRequest	G	Optional	inside the TrdgSesGrp component
OrderMassCancelReport	r	Optional	directly on the message body
OrderMassCancelRequest	q	Optional	directly on the message body
OrderMassStatusRequest	AF	Optional	directly on the message body
PositionMaintenanceReport	AM	Optional	inside the TrdgSesGrp component
PositionMaintenanceRequest	AL	Optional	inside the TrdgSesGrp component
Quote	S	Optional	directly on the message body
QuoteCancel	Z	Optional	directly on the message body
QuoteRequest	R	Optional	inside the QuotReqGrp component
QuoteRequestReject	AG	Optional	inside the QuotReqRjctGrp component
QuoteResponse	AJ	Optional	directly on the message body
QuoteStatusReport	AI	Optional	directly on the message body
QuoteStatusRequest	a	Optional	directly on the message body
RFQRequest	AH	Optional	inside the RFQReqGrp component
RequestForPositions	AN	Optional	inside the TrdgSesGrp component
SecurityDefinition	d	Optional	directly on the message body
SecurityDefinitionRequest	c	Optional	directly on the message body
SecurityList	y	Optional	inside the SecListGrp component
SecurityListRequest	x	Optional	directly on the message body
SecurityStatus	f	Optional	directly on the message body
SecurityStatusRequest	e	Optional	directly on the message body
SecurityTypeRequest	v	Optional	directly on the message body
SecurityTypes	w	Optional	directly on the message body
TradeCaptureReport	AE	Optional	inside the TrdCapRptSideGrp component
TradeCaptureReportRequest	AD	Optional	directly on the message body
TradingSessionStatus	h	Optional	directly on the message body
TradingSessionStatusRequest	g	Optional	directly on the message body

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 625 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[625];field?.name;   // "TradingSessionSubID"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