NoUnderlyingAmounts (FIX tag 984)

NumInGroupFIX 5.0 SP2group counter

NoUnderlyingAmounts (tag 984) is a NumInGroup field defined in FIX 5.0 SP2. It appears in 1 message type, 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
984
Name
NoUnderlyingAmounts
Datatype
NumInGroup (int)
Dialects
FIX 5.0 SP2
Messages
1

What the specification says

Total number of occurrences of Amount to pay in order to receive the underlying instrument

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

A real message using tag 984

PositionReport · FIX 5.0 SP2
TagFieldWire valueMeaning
8BeginStringFIXT.1.1
9BodyLength141
35MsgTypeAPPositionReport
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
721PosMaintRptIDEXAMPLE
715ClearingBusinessDate20240101
711NoUnderlyings1 entry1repeating group
311UnderlyingSymbolEXAMPLE
984NoUnderlyingAmounts2 entries2repeating group
985UnderlyingPayAmount125000.00
985UnderlyingPayAmount125000.00
10CheckSum003
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 5.0 SP2 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 984 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.

MessageMsgTypeRequirednessWhere in the message
PositionReportAPOptionalinside PosUndInstrmtGrp › UnderlyingAmount

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 984 in TypeScript

decode.tsts
import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix50sp2";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);// NoUnderlyingAmounts is a group counter, so the entries live on message.groups —// NOT on message.fields. message.fields[984] is undefined.const entries = message.groups[984] ?? [];for (const entry of entries) {  // entry.fields is keyed by tag; entry.groups holds nested groups}

Other NumInGroup fields

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-fix50sp2