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DiscretionInst (FIX tag 388)

charFIX 4.4FIX 4.2

DiscretionInst (tag 388) is a char field defined in FIX 4.4 and FIX 4.2. It appears in 8 message types, always optionally. It is an enumerated field with 7 defined values.

At a glance

Tag
388
Name
DiscretionInst
Datatype
char
Dialects
FIX 4.4 and FIX 4.2
Messages
8
Valid values
7

What the specification says

FIX 4.4

Code to identify the price a DiscretionOffsetValue (389) is related to and should be mathematically added to

FIX 4.2

Code to identify the price a DiscretionOffset is related to and should be mathematically added to.

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

A real message using tag 388

NewOrderSingle · FIX 4.4
TagFieldWire valueMeaning
8BeginStringFIX.4.4
9BodyLength117
35MsgTypeDOrder – Single
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
11ClOrdIDORD-10042
54Side1Buy
60TransactTime20240101-12:00:00.000
40OrdType1Market
388DiscretionInst0Related to displayed price
10CheckSum007
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.

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.

ValueMeaningSymbolic nameDialects
0Related to displayed priceRELATED_TO_DISPLAYED_PRICE / RelatedToDisplayedPriceFIX 4.4, FIX 4.2
1Related to market priceRELATED_TO_MARKET_PRICE / RelatedToMarketPriceFIX 4.4, FIX 4.2
2Related to primary priceRELATED_TO_PRIMARY_PRICE / RelatedToPrimaryPriceFIX 4.4, FIX 4.2
3Related to local primary priceRELATED_TO_LOCAL_PRIMARY_PRICE / RelatedToLocalPrimaryPriceFIX 4.4, FIX 4.2
4Related to midpoint priceRELATED_TO_MIDPOINT_PRICE / RelatedToMidpointPriceFIX 4.4, FIX 4.2
5Related to last trade priceRELATED_TO_LAST_TRADE_PRICE / RelatedToLastTradePriceFIX 4.4, FIX 4.2
6Related to VWAPRELATED_TO_VWAPFIX 4.4

Where tag 388 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.

MessageMsgTypeFIX 4.4FIX 4.2Where in the message
CrossOrderCancelReplaceRequesttOptional—inside the DiscretionInstructions component
ExecutionReport8OptionalOptionalinside the DiscretionInstructions component
MultilegOrderCancelReplaceACOptional—inside the DiscretionInstructions component
NewOrderCrosssOptional—inside the DiscretionInstructions component
NewOrderListEOptionalOptionalinside ListOrdGrp › DiscretionInstructions
NewOrderMultilegABOptional—inside the DiscretionInstructions component
NewOrderSingleDOptionalOptionalinside the DiscretionInstructions component
OrderCancelReplaceRequestGOptionalOptionalinside the DiscretionInstructions component

Wire format

A single character. Most char fields are enumerated, so the value is one of a fixed set rather than arbitrary text. @boarteam/fix keeps the value as a string and, for enumerated fields, reports validate/value-not-in-enum when it is not a defined value.

Read tag 388 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 discretionInst = message.fields[388]?.raw;// e.g. "0" — Related to displayed price​// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(388)  ?.enumValues?.find((e) => e.value === discretionInst)  ?.description;

Other char 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
Try the decoderSource on GitHub