OddLot (FIX tag 575)

BooleanFIX 4.4

OddLot (tag 575) is a Boolean field defined in FIX 4.4. It appears in 1 message type, always optionally. It is an enumerated field with 2 defined values.

At a glance

Tag: 575
Name: OddLot
Datatype: Boolean (char)
Dialects: FIX 4.4
Messages: 1
Valid values: 2

What the specification says

This trade is to be treated as an odd lot

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

A real message using tag 575

TradeCaptureReport · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	195
35	MsgType	AE	Trade Capture Report
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
571	TradeReportID	EXAMPLE
570	PreviouslyReported	N	not reported to counterparty
32	LastQty	1000000
31	LastPx	1.09210
75	TradeDate	20240101
60	TransactTime	20240101-12:00:00.000
552	NoSides2 entries	2	repeating group
54	Side	1	Buy
37	OrderID	ORD-10042
575	OddLot	N	treat as round lot
54	Side	1	Buy
37	OrderID	ORD-10042
575	OddLot	N	treat as round lot
10	CheckSum	150

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.

Valid values

A value outside this list is not a parse error — the message still decodes — but validate() reports it as validate/value-not-in-enum.

Value	Meaning	Symbolic name
Y	treat as odd lot	YES
N	treat as round lot	NO

Where tag 575 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
TradeCaptureReport	AE	Optional	inside the TrdCapRptSideGrp component

Wire format

Y or N. Not 1/0, and not true/false. @boarteam/fix keeps the value as a string and, for enumerated fields, reports validate/value-not-in-enum when it is not a defined value.

Read tag 575 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 oddLot = message.fields[575]?.raw;// e.g. "Y" — treat as odd lot// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(575)  ?.enumValues?.find((e) => e.value === oddLot)  ?.description;

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