MassCancelResponse (FIX tag 531)

charFIX 4.4

MassCancelResponse (tag 531) is a char field defined in FIX 4.4. It appears in 1 message type and is required in 1 of them. It is an enumerated field with 8 defined values.

At a glance

Tag: 531
Name: MassCancelResponse
Datatype: char
Dialects: FIX 4.4
Messages: 1
Valid values: 8

What the specification says

Specifies the action taken by counterparty order handling system as a result of the Order Mass Cancel Request

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

A real message using tag 531

OrderMassCancelReport · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	88
35	MsgType	r	Order Mass Cancel Report
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
37	OrderID	ORD-10042
530	MassCancelRequestType	1	Cancel orders for a security
531	MassCancelResponse	0	Cancel Request Rejected -- See MassCancelRejectReason (532)
10	CheckSum	182

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
0	Cancel Request Rejected -- See MassCancelRejectReason (532)	CANCEL_REQUEST_REJECTED
1	Cancel orders for a security	CANCEL_ORDERS_FOR_A_SECURITY
2	Cancel orders for an Underlying security	CANCEL_ORDERS_FOR_AN_UNDERLYING_SECURITY
3	Cancel orders for a Product	CANCEL_ORDERS_FOR_A_PRODUCT
4	Cancel orders for a CFICode	CANCEL_ORDERS_FOR_A_CFICODE
5	Cancel orders for a SecurityType	CANCEL_ORDERS_FOR_A_SECURITYTYPE
6	Cancel orders for a trading session	CANCEL_ORDERS_FOR_A_TRADING_SESSION
7	Cancel all orders	CANCEL_ALL_ORDERS

Where tag 531 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
OrderMassCancelReport	r	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 531 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 massCancelResponse = message.fields[531]?.raw;// e.g. "0" — Cancel Request Rejected -- See MassCancelRejectReason (532)// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(531)  ?.enumValues?.find((e) => e.value === massCancelResponse)  ?.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