MDSecSize (FIX tag 1179)

QtyFIX 5.0 SP2

MDSecSize (tag 1179) is a Qty field defined in FIX 5.0 SP2. It appears in 2 message types, always optionally.

At a glance

Tag
1179
Name
MDSecSize
Datatype
Qty (float)
Dialects
FIX 5.0 SP2
Messages
2

What the specification says

A part of the MDEntrySize(271) that represents secondary interest as specified by MDSecSizeType(1178).

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

A real message using tag 1179

MarketDataSnapshotFullRefresh · FIX 5.0 SP2
TagFieldWire valueMeaning
8BeginStringFIXT.1.1
9BodyLength122
35MsgTypeWMarketDataSnapshotFullRefresh
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
268NoMDEntries1 entry1repeating group
269MDEntryType0Bid
1177NoOfSecSizes2 entries2repeating group
1178MDSecSizeType1Customer
1179MDSecSize1000000
1178MDSecSizeType1Customer
1179MDSecSize1000000
10CheckSum239
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 1179 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
MarketDataIncrementalRefreshXOptionalinside MDIncGrp › SecSizesGrp
MarketDataSnapshotFullRefreshWOptionalinside MDFullGrp › SecSizesGrp

Wire format

A decimal quantity. Fractional quantities are legal, which is why this is a float family rather than an integer. @boarteam/fix parses the value as a number and reports parse/invalid-float when it does not lex as one; the raw string is kept so precision and trailing zeros are never lost.

Read tag 1179 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);const field = message.fields[1179];field?.name;   // "MDSecSize"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a number

Other Qty 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