DKReason (FIX tag 127)

charFIX 4.4FIX 4.2FIX 5.0 SP2

DKReason (tag 127) is a char field defined in FIX 4.4, FIX 4.2 and FIX 5.0 SP2. It appears in 1 message type and is required in 1 of them. It is an enumerated field with 7 defined values.

At a glance

Tag: 127
Name: DKReason
Datatype: char
Dialects: FIX 4.4, FIX 4.2 and FIX 5.0 SP2
Messages: 1
Valid values: 7

What the specification says

FIX 4.4

Reason for execution rejection

FIX 4.2

Reason for execution rejection.

FIX 5.0 SP2

Reason for execution rejection.

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

A real message using tag 127

DontKnowTrade · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	101
35	MsgType	Q	Don’t Know Trade (DK)
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
37	OrderID	ORD-10042
17	ExecID	EXEC-88117
127	DKReason	A	Unknown symbol
54	Side	1	Buy
10	CheckSum	155

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	Dialects
A	Unknown symbol	UNKNOWN_SYMBOL / UnknownSymbol	FIX 4.4, FIX 4.2, FIX 5.0 SP2
B	Wrong side	WRONG_SIDE / WrongSide	FIX 4.4, FIX 4.2, FIX 5.0 SP2
C	Quantity exceeds order	QUANTITY_EXCEEDS_ORDER / QuantityExceedsOrder	FIX 4.4, FIX 4.2, FIX 5.0 SP2
D	No matching order	NO_MATCHING_ORDER / NoMatchingOrder	FIX 4.4, FIX 4.2, FIX 5.0 SP2
E	Price exceeds limit	PRICE_EXCEEDS_LIMIT / PriceExceedsLimit	FIX 4.4, FIX 4.2, FIX 5.0 SP2
F	Calculation difference	CALCULATION_DIFFERENCE	FIX 4.4, FIX 5.0 SP2
Z	Other	OTHER / Other	FIX 4.4, FIX 4.2, FIX 5.0 SP2

Where tag 127 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
DontKnowTrade	Q	Required	Required	Required	directly on the message body
ExecutionAcknowledgement	BN	—	—	Optional	directly on the message body

Wire format

A single character. Most char fields are enumerated, so the value is one of a fixed set rather than arbitrary text. @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 127 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 dKReason = message.fields[127]?.raw;// e.g. "A" — Unknown symbol// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(127)  ?.enumValues?.find((e) => e.value === dKReason)  ?.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