LegPrice (FIX tag 566)

PriceFIX 4.4

LegPrice (tag 566) is a Price field defined in FIX 4.4. It appears in 5 message types, always optionally.

At a glance

Tag: 566
Name: LegPrice
Datatype: Price (float)
Dialects: FIX 4.4
Messages: 5

What the specification says

Price for leg of a multileg See Price (44) field for description

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

A real message using tag 566

ExecutionReport · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	187
35	MsgType	8	Execution Report
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
37	OrderID	ORD-10042
17	ExecID	EXEC-88117
150	ExecType	0	New
39	OrdStatus	0	New
54	Side	1	Buy
151	LeavesQty	0
14	CumQty	1000000
6	AvgPx	1.09215
555	NoLegs2 entries	2	repeating group
600	LegSymbol	EXAMPLE
566	LegPrice	1.09210
600	LegSymbol	EXAMPLE
566	LegPrice	1.09210
10	CheckSum	101

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 566 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
ExecutionReport	8	Optional	inside the InstrmtLegExecGrp component
MultilegOrderCancelReplace	AC	Optional	inside the LegOrdGrp component
NewOrderMultileg	AB	Optional	inside the LegOrdGrp component
TradeCaptureReport	AE	Optional	inside the TrdInstrmtLegGrp component
TradeCaptureReportAck	AR	Optional	inside the TrdInstrmtLegGrp component

Wire format

A decimal price. Precision is a venue convention, not a protocol rule, so compare the raw string when exactness matters. @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 566 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[566];field?.name;   // "LegPrice"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