DKReason (FIX tag 127)

charFIX 4.4FIX 4.2

DKReason (tag 127) is a char 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 7 defined values.

At a glance

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

What the specification says

FIX 4.4

Reason for execution rejection

FIX 4.2

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

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	Where in the message
DontKnowTrade	Q	Required	Required	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