LegAllocQty (FIX tag 673)

QtyFIX 4.4

LegAllocQty (tag 673) is a Qty field defined in FIX 4.4. It appears in 2 message types, always optionally.

At a glance

Tag: 673
Name: LegAllocQty
Datatype: Qty (float)
Dialects: FIX 4.4
Messages: 2

What the specification says

Leg allocation quantity. See AllocQty (80) for description and valid values.

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

A real message using tag 673

NewOrderMultileg · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	184
35	MsgType	AB	New Order - Multileg
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
11	ClOrdID	ORD-10042
54	Side	1	Buy
555	NoLegs1 entry	1	repeating group
600	LegSymbol	EXAMPLE
670	NoLegAllocs2 entries	2	repeating group
671	LegAllocAccount	EXAMPLE
673	LegAllocQty	1000000
671	LegAllocAccount	EXAMPLE
673	LegAllocQty	1000000
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	098

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 673 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
MultilegOrderCancelReplace	AC	Optional	inside LegOrdGrp › LegPreAllocGrp
NewOrderMultileg	AB	Optional	inside LegOrdGrp › LegPreAllocGrp

Wire format

A decimal quantity. Fractional quantities are legal, which is why this is a float family rather than an integer. @boarteam/fix parses the value as a number and reports parse/invalid-float when it does not lex as one; the raw string is kept so precision and trailing zeros are never lost.

Read tag 673 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[673];field?.name;   // "LegAllocQty"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