PrevClosePx (FIX tag 140)

PriceFIX 4.4FIX 4.2

PrevClosePx (tag 140) is a Price field defined in FIX 4.4 and FIX 4.2. It appears in 10 message types, always optionally.

At a glance

Tag: 140
Name: PrevClosePx
Datatype: Price (float)
Dialects: FIX 4.4 and FIX 4.2
Messages: 10

What the specification says

Previous closing price of security.

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

A real message using tag 140

NewOrderSingle · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	123
35	MsgType	D	Order – Single
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
11	ClOrdID	ORD-10042
140	PrevClosePx	1.09210
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	033

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 140 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
CrossOrderCancelReplaceRequest	t	Optional	—	directly on the message body
ListStrikePrice	m	Optional	Optional	inside the UndInstrmtStrkPxGrp component
MultilegOrderCancelReplace	AC	Optional	—	directly on the message body
NewOrderCross	s	Optional	—	directly on the message body
NewOrderList	E	Optional	Optional	inside the ListOrdGrp component
NewOrderMultileg	AB	Optional	—	directly on the message body
NewOrderSingle	D	Optional	Optional	directly on the message body
QuoteRequest	R	Optional	Optional	inside the QuotReqGrp component
QuoteRequestReject	AG	Optional	—	inside the QuotReqRjctGrp component
RFQRequest	AH	Optional	—	inside the RFQReqGrp component

Wire format

A decimal price. Precision is a venue convention, not a protocol rule, so compare the raw string when exactness matters. @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 140 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[140];field?.name;   // "PrevClosePx"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