ExecInst (FIX tag 18)

At a glance

Tag

18

Name

ExecInst

Datatype

MultipleValueString (String)

Dialects

FIX 4.4 and FIX 4.2

Messages

11

Valid values

40

What the specification says

Instructions for order handling on exchange trading floor. If more than one instruction is applicable to an order, this field can contain multiple instructions separated by space.

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

A real message using tag 18

Valid values

A value outside this list is not a parse error — the message still decodes — but validate() reports it as validate/value-not-in-enum.

Where tag 18 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.

Wire format

Several values in one field, separated by spaces. Decoders return an array. @boarteam/fix splits the value on its delimiter and returns an array of strings.

Read tag 18 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 execInst = message.fields[18]?.raw;// e.g. "1" — Not held​// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(18)  ?.enumValues?.find((e) => e.value === execInst)  ?.description;

Other MultipleValueString fields

• 276QuoteCondition
• 277TradeCondition
• 286OpenCloseSettlFlag
• 291FinancialStatus
• 292CorporateAction
• 529OrderRestrictions
• 546Scope