EncodedUnderlyingSecurityDescLen (FIX tag 364)

LengthFIX 4.4FIX 4.2FIX 5.0 SP2

EncodedUnderlyingSecurityDescLen (tag 364) is a Length field defined in FIX 4.4, FIX 4.2 and FIX 5.0 SP2. It appears in 59 message types, always optionally.

At a glance

Tag: 364
Name: EncodedUnderlyingSecurityDescLen
Datatype: Length (int)
Dialects: FIX 4.4, FIX 4.2 and FIX 5.0 SP2
Messages: 59

What the specification says

FIX 4.4

Byte length of encoded (non-ASCII characters) EncodedUnderlyingSecurityDesc (365) field.

FIX 4.2

Byte length of encoded (non-ASCII characters) EncodedUnderlyingSecurityDesc field.

FIX 5.0 SP2

Byte length of encoded (non-ASCII characters) EncodedUnderlyingSecurityDesc (365) field.

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

A real message using tag 364

NewOrderSingle · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	153
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
711	NoUnderlyings2 entries	2	repeating group
311	UnderlyingSymbol	EXAMPLE
364	EncodedUnderlyingSecurityDescLen	7
311	UnderlyingSymbol	EXAMPLE
364	EncodedUnderlyingSecurityDescLen	7
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	225

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 364 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 4.2	FIX 5.0 SP2	Where in the message
Advertisement	7	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
AllocationInstruction	J	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
AllocationInstructionAlert	BM	—	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
AllocationReport	AS	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
AssignmentReport	AW	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CollateralAssignment	AY	Conditional	—	Optional	inside UndInstrmtCollGrp › UnderlyingInstrument
CollateralInquiry	BB	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CollateralInquiryAck	BG	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CollateralReport	BA	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CollateralRequest	AX	Conditional	—	Optional	inside UndInstrmtCollGrp › UnderlyingInstrument
CollateralResponse	AZ	Conditional	—	Optional	inside UndInstrmtCollGrp › UnderlyingInstrument
Confirmation	AK	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
ContraryIntentionReport	BO	—	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CrossOrderCancelReplaceRequest	t	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
CrossOrderCancelRequest	u	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
DerivativeSecurityList	AA	Conditional	—	Optional	inside the UnderlyingInstrument component
DerivativeSecurityListRequest	z	Conditional	—	Optional	inside the UnderlyingInstrument component
DerivativeSecurityListUpdateReport	BR	—	—	Optional	inside the UnderlyingInstrument component
DontKnowTrade	Q	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
Email	C	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
ExecutionAcknowledgement	BN	—	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
ExecutionReport	8	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
IOI	6	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
ListStrikePrice	m	Conditional	—	Optional	inside UndInstrmtStrkPxGrp › UnderlyingInstrument
MarketDataIncrementalRefresh	X	Conditional	—	Optional	inside MDIncGrp › UndInstrmtGrp › UnderlyingInstrument
MarketDataRequest	V	Conditional	—	Optional	inside InstrmtMDReqGrp › UndInstrmtGrp › UnderlyingInstrument
MarketDataSnapshotFullRefresh	W	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
MassQuote	i	Conditional	Optional	Optional	inside QuotSetGrp › UnderlyingInstrument
MassQuoteAcknowledgement	b	Conditional	Optional	Optional	inside QuotSetAckGrp › UnderlyingInstrument
MultilegOrderCancelReplace	AC	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
NewOrderCross	s	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
NewOrderList	E	Conditional	—	Optional	inside ListOrdGrp › UndInstrmtGrp › UnderlyingInstrument
NewOrderMultileg	AB	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
NewOrderSingle	D	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
News	B	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
OrderCancelReplaceRequest	G	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
OrderCancelRequest	F	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
OrderMassActionReport	BZ	—	—	Optional	inside the UnderlyingInstrument component
OrderMassActionRequest	CA	—	—	Optional	inside the UnderlyingInstrument component
OrderMassCancelReport	r	Conditional	—	Optional	inside the UnderlyingInstrument component
OrderMassCancelRequest	q	Conditional	—	Optional	inside the UnderlyingInstrument component
OrderMassStatusRequest	AF	Conditional	—	Optional	inside the UnderlyingInstrument component
OrderStatusRequest	H	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
PositionMaintenanceReport	AM	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
PositionMaintenanceRequest	AL	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
PositionReport	AP	Conditional	—	Optional	inside PosUndInstrmtGrp › UnderlyingInstrument
Quote	S	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
QuoteCancel	Z	Conditional	—	Optional	inside QuotCxlEntriesGrp › UndInstrmtGrp › UnderlyingInstrument
QuoteRequest	R	Conditional	—	Optional	inside QuotReqGrp › UndInstrmtGrp › UnderlyingInstrument
QuoteRequestReject	AG	Conditional	—	Optional	inside QuotReqRjctGrp › UndInstrmtGrp › UnderlyingInstrument
QuoteResponse	AJ	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
QuoteStatusReport	AI	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
QuoteStatusRequest	a	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
RFQRequest	AH	Conditional	—	Optional	inside RFQReqGrp › UndInstrmtGrp › UnderlyingInstrument
RequestForPositions	AN	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
RequestForPositionsAck	AO	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityDefinition	d	Conditional	Optional	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityDefinitionRequest	c	Conditional	Optional	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityDefinitionUpdateReport	BP	—	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityList	y	Conditional	—	Optional	inside SecListGrp › UndInstrmtGrp › UnderlyingInstrument
SecurityListRequest	x	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityListUpdateReport	BK	—	—	Optional	inside SecLstUpdRelSymGrp › UndInstrmtGrp › UnderlyingInstrument
SecurityStatus	f	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
SecurityStatusRequest	e	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
TradeCaptureReport	AE	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
TradeCaptureReportAck	AR	—	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
TradeCaptureReportRequest	AD	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument
TradeCaptureReportRequestAck	AQ	Conditional	—	Optional	inside UndInstrmtGrp › UnderlyingInstrument

Wire format

A byte count for the length-prefixed field that follows it. Count bytes, not characters — a multi-byte UTF-8 value makes the two differ. @boarteam/fix parses the value as a number and reports parse/invalid-int when it does not lex as one; the raw string is kept either way.

Read tag 364 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[364];field?.name;   // "EncodedUnderlyingSecurityDescLen"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a number

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