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title: Security Definition Request <c> message – FIX 4.4 – FIX Dictionary – Onix Solutions
description: Security Definition Request <c> message – FIX 4.4 – FIX Dictionary – Onix Solutions
---

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# Security Definition Request <c> message – FIX 4.4 – FIX Dictionary

| Messages by MsgType \| Messages by Name \| Fields by Tag \| Fields by Name \| FIX 4.4 \| Home FIX 4.4 : Security Definition Request <c> message Structure \| Related Messages Description The Security Definition Request <c> message is used for the following: Request a specific Security to be traded with the second party. The request security can be defined as a multileg security made up of one or more instrument legs. Subscription for security status can be optionally specified by including the SubscriptionRequestType <263> field on the message. See Appendix I: Security Definition, Security Status, and Trading Session Message Scenarios Structure Tag Field Name Req'd Comments <MessageHeader> Y MsgType <35> = c 320 SecurityReqID Y 321 SecurityRequestType Y Component Block - <Instrument> N Insert here the set of "<Instrument>" (symbology) fields of the requested Security Component Block - <InstrumentExtension> N Insert here the set of "<InstrumentExtension>" fields 711 NoUnderlyings N Number of underlyings => Component Block - <UnderlyingInstrument> N Must be provided if Number of underlyings > 0 15 Currency N 58 Text N Comment, instructions, or other identifying information. 354 EncodedTextLen N Must be set if EncodedText <355> field is specified and must immediately precede it. 355 EncodedText N Encoded (non-ASCII characters) representation of the Text <58> field in the encoded format specified via the MessageEncoding <347> field. 336 TradingSessionID N Optional Trading Session Identifier to specify a particular trading session for which you want to obtain a list of securities that are tradeable. 625 TradingSessionSubID N 555 NoLegs N Number of legs that make up the Security => Component Block - <InstrumentLeg> N Insert here the set of "<InstrumentLeg>" (leg-specific symbology) fields Required if NoLegs <555> > 0. 827 ExpirationCycle N 263 SubscriptionRequestType N Subscribe or unsubscribe for security status to security specified in request. <MessageTrailer> Y   Related Messages Security Definition <d> Security Status <f> |
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