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NoInstrAttrib (FIX tag 870)

NumInGroupFIX 4.4group counter

NoInstrAttrib (tag 870) is a NumInGroup field defined in FIX 4.4. 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
870
Name
NoInstrAttrib
Datatype
NumInGroup (int)
Dialects
FIX 4.4
Messages
11

What the specification says

Number of repeating InstrAttribType entries.

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

A real message using tag 870

AllocationInstruction · FIX 4.4
TagFieldWire valueMeaning
8BeginStringFIX.4.4
9BodyLength147
35MsgTypeJAllocation Instruction
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
70AllocIDEXAMPLE
71AllocTransType0New
626AllocType1Calculated (includes MiscFees and NetMoney)
857AllocNoOrdersType0Not specified
54Side1Buy
870NoInstrAttrib2 entries2repeating group
871InstrAttribType1Flat (securities pay interest on a current basis but are traded without interest)
871InstrAttribType1Flat (securities pay interest on a current basis but are traded without interest)
53Quantity1000000
6AvgPx1.09215
75TradeDate20240101
10CheckSum165
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 870 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
AllocationInstructionJOptionalinside InstrumentExtension › AttrbGrp
AllocationReportASOptionalinside InstrumentExtension › AttrbGrp
ConfirmationAKOptionalinside InstrumentExtension › AttrbGrp
DerivativeSecurityListAAOptionalinside RelSymDerivSecGrp › InstrumentExtension › AttrbGrp
SecurityDefinitiondOptionalinside InstrumentExtension › AttrbGrp
SecurityDefinitionRequestcOptionalinside InstrumentExtension › AttrbGrp
SecurityListyOptionalinside SecListGrp › InstrumentExtension › AttrbGrp
SecurityListRequestxOptionalinside InstrumentExtension › AttrbGrp
SecurityStatusfOptionalinside InstrumentExtension › AttrbGrp
SecurityStatusRequesteOptionalinside InstrumentExtension › AttrbGrp
TradeCaptureReportRequestADOptionalinside InstrumentExtension › AttrbGrp

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 870 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);​// NoInstrAttrib is a group counter, so the entries live on message.groups —// NOT on message.fields. message.fields[870] is undefined.const entries = message.groups[870] ?? [];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-fix44
Try the decoderSource on GitHub