LastMkt (FIX tag 30)
LastMkt (tag 30) is an Exchange field defined in FIX 4.4 and FIX 4.2. It appears in 6 message types, always optionally.
At a glance
- Tag
- 30
- Name
- LastMkt
- Datatype
- Exchange (String)
- Dialects
- FIX 4.4 and FIX 4.2
- Messages
- 6
What the specification says
FIX 4.4
Market of execution for last fill, or an indication of the market where an order was routed Valid values: See "Appendix 6-C"
FIX 4.2
Market of execution for last fill
Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.
A real message using tag 30
| Tag | Field | Wire value | Meaning |
|---|---|---|---|
| 8 | BeginString | FIX.4.4 | |
| 9 | BodyLength | 141 | |
| 35 | MsgType | 8 | Execution Report |
| 49 | SenderCompID | BOARTEAM | |
| 56 | TargetCompID | COUNTERPARTY | |
| 34 | MsgSeqNum | 2 | |
| 52 | SendingTime | 20240101-12:00:00.000 | |
| 37 | OrderID | ORD-10042 | |
| 17 | ExecID | EXEC-88117 | |
| 150 | ExecType | 0 | New |
| 39 | OrdStatus | 0 | New |
| 54 | Side | 1 | Buy |
| 30 | LastMkt | XNAS | |
| 151 | LeavesQty | 0 | |
| 14 | CumQty | 1000000 | |
| 6 | AvgPx | 1.09215 | |
| 10 | CheckSum | 243 |
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.
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 30 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 |
|---|---|---|---|---|
| Advertisement | 7 | Optional | Optional | directly on the message body |
| AllocationInstruction | J | Optional | Optional | directly on the message body |
| AllocationReport | AS | Optional | — | directly on the message body |
| Confirmation | AK | Optional | — | directly on the message body |
| ExecutionReport | 8 | Optional | Optional | directly on the message body |
| SettlementInstructions | T | — | Optional | directly on the message body |
| TradeCaptureReport | AE | Optional | — | directly on the message body |
Wire format
A market identifier, in practice an ISO 10383 MIC. @boarteam/fix keeps the value as a string; format rules are checked by validate(), which reports validate/invalid-value rather than throwing.
Read tag 30 in TypeScript
import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix44";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const field = message.fields[30];field?.name; // "LastMkt"field?.raw; // the verbatim wire stringfield?.value; // coerced to a stringOther Exchange 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