CrossPrioritization (FIX tag 550)

intFIX 4.4

CrossPrioritization (tag 550) is an int field defined in FIX 4.4. It appears in 3 message types and is required in 3 of them. It is an enumerated field with 3 defined values.

At a glance

Tag: 550
Name: CrossPrioritization
Datatype: int
Dialects: FIX 4.4
Messages: 3
Valid values: 3

What the specification says

Indicates if one side or the other of a cross order should be prioritized. The definition of prioritization is left to the market. In some markets prioritization means which side of the cross order is applied to the market first. In other markets – prioritization may mean that the prioritized side is fully executed (sometimes referred to as the side being protected).

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

A real message using tag 550

CrossOrderCancelRequest · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	161
35	MsgType	u	Cross Order Cancel Request
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
548	CrossID	EXAMPLE
551	OrigCrossID	EXAMPLE
549	CrossType	1	Cross Trade which is executed completely or not. Both sides are treated in the same manner. This is equivalent to an All or None.
550	CrossPrioritization	0	None
552	NoSides1 entry	1	repeating group
54	Side	1	Buy
41	OrigClOrdID	ORD-10041
11	ClOrdID	ORD-10042
60	TransactTime	20240101-12:00:00.000
10	CheckSum	242

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	None	NONE
1	Buy side is prioritized	BUY_SIDE_IS_PRIORITIZED
2	Sell side is prioritized	SELL_SIDE_IS_PRIORITIZED

Where tag 550 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
CrossOrderCancelReplaceRequest	t	Required	directly on the message body
CrossOrderCancelRequest	u	Required	directly on the message body
NewOrderCross	s	Required	directly on the message body

Wire format

A whole number, optionally signed. Leading zeros are legal on the wire and are preserved in the raw value. @boarteam/fix parses the value as a number and reports parse/invalid-int when it does not lex as one; the raw string is kept either way.

Read tag 550 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 crossPrioritization = message.fields[550]?.raw;// e.g. "0" — None// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(550)  ?.enumValues?.find((e) => e.value === crossPrioritization)  ?.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