IOIQty (FIX tag 27)

StringFIX 4.4FIX 4.2

IOIQty (tag 27) is a String field defined in FIX 4.4 and FIX 4.2. It appears in 1 message type and is required in 1 of them. It is an enumerated field with 3 defined values. FIX 4.2 calls this field IOIShares; the tag number is unchanged, so the two are the same field on the wire.

Also known as IOIShares

FIX 4.2 calls tag 27 IOIShares. It is the same field on the wire — only the name changed — so a message encoded by either side interoperates.

At a glance

Tag: 27
Name: IOIQty
Datatype: String
Dialects: FIX 4.4 and FIX 4.2
Messages: 1
Valid values: 3

What the specification says

FIX 4.4

Quantity (e.g. number of shares) in numeric form or relative size.

FIX 4.2

Number of shares in numeric or relative size.

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

A real message using tag 27

IOI · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	89
35	MsgType	6	Indication of Interest
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
23	IOIID	EXAMPLE
28	IOITransType	N	New
54	Side	1	Buy
27	IOIQty	S	Small
10	CheckSum	051

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
S	Small	SMALL / Small
M	Medium	MEDIUM / Medium
L	Large	LARGE / Large

Where tag 27 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	Where in the message
IOI	6	Required	Required	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 27 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 iOIQty = message.fields[27]?.raw;// e.g. "S" — Small// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(27)  ?.enumValues?.find((e) => e.value === iOIQty)  ?.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