StartCash (FIX tag 921)

AmtFIX 4.4

StartCash (tag 921) is an Amt field defined in FIX 4.4. It appears in 10 message types, always optionally.

At a glance

Tag: 921
Name: StartCash
Datatype: Amt (float)
Dialects: FIX 4.4
Messages: 10

What the specification says

Starting dirty cash consideration of a financing deal, i.e. paid to the seller on the Start Date.

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

A real message using tag 921

ExecutionReport · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	147
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
151	LeavesQty	0
14	CumQty	1000000
6	AvgPx	1.09215
921	StartCash	125000.00
10	CheckSum	174

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 921 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	Requiredness	Where in the message
AllocationInstruction	J	Optional	directly on the message body
AllocationReport	AS	Optional	directly on the message body
CollateralAssignment	AY	Optional	directly on the message body
CollateralInquiry	BB	Optional	directly on the message body
CollateralReport	BA	Optional	directly on the message body
CollateralRequest	AX	Optional	directly on the message body
CollateralResponse	AZ	Optional	directly on the message body
Confirmation	AK	Optional	directly on the message body
ExecutionReport	8	Optional	directly on the message body
TradeCaptureReport	AE	Optional	inside the TrdCapRptSideGrp component

Wire format

A decimal monetary amount, in the currency named by the message's currency field. @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 921 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);const field = message.fields[921];field?.name;   // "StartCash"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a number

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