NoTradingSessions (FIX tag 386)

NumInGroupFIX 4.4FIX 4.2group counter

NoTradingSessions (tag 386) is a NumInGroup field defined in FIX 4.4 and FIX 4.2. It appears in 11 message types, always optionally. Its datatype is NumInGroup, which makes it a repeating-group counter: its value is the number of entries that follow, not a quantity in its own right.

At a glance

Tag: 386
Name: NoTradingSessions
Datatype: NumInGroup (int)
Dialects: FIX 4.4 and FIX 4.2
Messages: 11

What the specification says

FIX 4.4

Number of TradingSessionIDs (336) in repeating group.

FIX 4.2

Number of TradingSessionIDs in repeating group.

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

A real message using tag 386

OrderCancelReplaceRequest · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	154
35	MsgType	G	Order Cancel/Replace Request
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
41	OrigClOrdID	ORD-10041
11	ClOrdID	ORD-10042
386	NoTradingSessions2 entries	2	repeating group
336	TradingSessionID	REGULAR
336	TradingSessionID	REGULAR
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	142

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.

Where tag 386 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
CrossOrderCancelReplaceRequest	t	Optional	—	inside the TrdgSesGrp component
MarketDataRequest	V	Optional	—	inside the TrdgSesGrp component
MultilegOrderCancelReplace	AC	Optional	—	inside the TrdgSesGrp component
NewOrderCross	s	Optional	—	inside the TrdgSesGrp component
NewOrderList	E	Optional	Optional	inside ListOrdGrp › TrdgSesGrp
NewOrderMultileg	AB	Optional	—	inside the TrdgSesGrp component
NewOrderSingle	D	Optional	Optional	inside the TrdgSesGrp component
OrderCancelReplaceRequest	G	Optional	Optional	inside the TrdgSesGrp component
PositionMaintenanceReport	AM	Optional	—	inside the TrdgSesGrp component
PositionMaintenanceRequest	AL	Optional	—	inside the TrdgSesGrp component
RequestForPositions	AN	Optional	—	inside the TrdgSesGrp component

Wire format

The number of entries in the repeating group that follows. The next field on the wire is the group's delimiter tag. @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 386 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);// NoTradingSessions is a group counter, so the entries live on message.groups —// NOT on message.fields. message.fields[386] is undefined.const entries = message.groups[386] ?? [];for (const entry of entries) {  // entry.fields is keyed by tag; entry.groups holds nested groups}

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