---
title: "FIX 5.0 SP2 EP299: <RelatedInstrumentGrp> component block – FIX Dictionary – Onix Solutions"
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# <RelatedInstrumentGrp> component block

## FIX 5.0 SP2 EP299

### Description

 The RelatedInstrumentGrp is a repeating component at the same hierarchical level as the Instrument component, describing relationships and linkages between the Instrument, UnderlyingInstrument and InstrumentLeg entries. If all instances of the UnderlyingInstrument in the message are true underliers of the Instrument then the RelatedInstrumentGrp component is not needed. If any instance of the UnderlyingInstrument has a different relationship, e.g. underlier of an InstrumentLeg, stream, equity equivalent or nearest exchange-traded contract or there are multiple instances of InstrumentLeg, then an entry for every relationship should be included in this component. When the RelatedInstrumentGrp appears within a repeating group, each entry only apply to the Instrument component at the same hierarchical level.

 In messages, such as [Email <C>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_C_67.html) and [News <B>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_B_66.html), where Instrument and the InstrumentLeg are within their repeating groups, the RelatedInstrumentGrp component may be used to link legs and underliers to their appropriate base Instrument.

 For simple relationships such as identifying a "hedges for" security the entry simply defines the symbol or identifier of an externally known security. For relationships within strategies and swaps the entry refers up through one of the "related to" fields to the Instrument, InstrumentLeg, UnderlyingInstrument, stream or dividend period with which the related security has correlation. It then points down through [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) or [RelatedSymbol <1649>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) to an UnderlyingInstrument instance in the current message defining the related security. The nature of the relationship is given in [RelatedInstrumentType <1648>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1648.html).

### Structure

| Tag | Field Name | Req'd | Comments |  |
| --- | --- | --- | --- | --- |
| 1647 | [NoRelatedInstruments](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1647.html) | N |  |  |
| → | 1648 | [RelatedInstrumentType](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1648.html) | N | Conditionally required when NoRelatedInstruments > 0 |
| → | 1649 | [RelatedSymbol](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) | N | Either [RelatedSymbol <1649>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) or [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) must be specified. For [RelatedInstrumentType <1648>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1648.html)=1 ("hedges for" instrument) this would be the instrument being used to offset the option Instrument. If one of the "related to" fields is specified, this is the [UnderlyingSymbol <311>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_311.html) of an underlying instrument defining the related security in the current message. |
| → | 1650 | [RelatedSecurityID](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) | N | Either [RelatedSymbol <1649>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) or [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) must be specified. If one of the "related to" fields is specified, this is the [UnderlyingSecurityID <309>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_309.html) of an underlying instrument defining the related security in the current message. |
| → | 1651 | [RelatedSecurityIDSource](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1651.html) | N | Conditionally required when [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) is specified. |
| → | 1652 | [RelatedSecurityType](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1652.html) | N | May be omitted if [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) or [RelatedSymbol <1649>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) refers to an underlying instrument in the current message. |
| → | 1653 | [RelatedMaturityMonthYear](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1653.html) | N | May be omitted if [RelatedSecurityID <1650>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1650.html) or [RelatedSymbol <1649>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_1649.html) refers to an underlying instrument in the current message. |
| → | 2413 | [RelatedToSecurityID](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2413.html) | N | Mutually exclusive with [RelatedToStreamXIDRef <2415>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2415.html) and [RelatedToDividendPeriodXIDRef <2417>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2417.html). If correlation is with the security in Instrument component then all "related to" fields may be omitted. |
| → | 2414 | [RelatedToSecurityIDSource](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2414.html) | N | Conditionally required when [RelatedToSecurityID <2413>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2413.html) is specified. |
| → | 2415 | [RelatedToStreamXIDRef](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2415.html) | N | Mutually exclusive with [RelatedToSecurityID <2413>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2413.html) and [RelatedToDividendPeriodXIDRef <2417>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2417.html). If correlation is with the security in Instrument component then all "related to" fields may be omitted. |
| → | 2417 | [RelatedToDividendPeriodXIDRef](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2417.html) | N | Mutually exclusive with [RelatedToSecurityID <2413>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2413.html) and [RelatedToStreamXIDRef <2415>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/tagNum_2415.html). If correlation is with the security in Instrument component then all "related to" fields may be omitted. |

### Used In

- [<InstrmtGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_InstrmtGrp.html)
- [<InstrmtMDReqGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_InstrmtMDReqGrp.html)
- [<MDIncGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_MDIncGrp.html)
- [<SecListGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_SecListGrp.html)
- [<SecLstUpdRelSymGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_SecLstUpdRelSymGrp.html)
- [<SecMassStatGrp>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/compBlock_SecMassStatGrp.html)
- [IOI <6>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_6_6.html)
- [Advertisement <7>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_7_7.html)
- [TradeCaptureReport <AE>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_AE_6569.html)
- [PositionMaintenanceRequest <AL>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_AL_6576.html)
- [PositionMaintenanceReport <AM>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_AM_6577.html)
- [PositionReport <AP>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_AP_6580.html)
- [SecurityDefinitionUpdateReport <BP>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_BP_6680.html)
- [MarketDataStatisticsRequest <DO>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_DO_6879.html)
- [MarketDataStatisticsReport <DP>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_DP_6880.html)
- [MarketDataSnapshotFullRefresh <W>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_W_87.html)
- [SecurityDefinitionRequest <c>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_c_99.html)
- [SecurityDefinition <d>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_d_100.html)
- [SecurityStatusRequest <e>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_e_101.html)
- [SecurityStatus <f>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_f_102.html)
- [SecurityListRequest <x>](https://www.onixs.biz/fix-dictionary/5.0.sp2.ep299/msgType_x_120.html)

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