# Changing of CompID

**URL:** <https://forum.fixtrading.org/t/changing-of-compid/3815>\
**Category:** General Q&A\
**Tags:** xid\_167105, general-qa, imported\
**Created:** [March 22, 2000, 5:18am UTC](https://forum.fixtrading.org/t/changing-of-compid/3815 "2000-03-22T05:18:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![blan\_x](https://avatars.discourse-cdn.com/v4/letter/b/2acd7d/32.png) [@blan\_x](https://forum.fixtrading.org/u/blan_x)\
**Post date:** [March 22, 2000, 5:18am UTC](https://forum.fixtrading.org/t/changing-of-compid/3815/1 "2000-03-22T05:18:00Z")

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Imported from previous forum

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**Author:** ![blan\_x](https://avatars.discourse-cdn.com/v4/letter/b/2acd7d/32.png) [@blan\_x](https://forum.fixtrading.org/u/blan_x)\
**Post date:** [March 22, 2000, 5:18am UTC](https://forum.fixtrading.org/t/changing-of-compid/3815/2 "2000-03-22T05:18:00Z")

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Hi, All!

Does anybody of FIX committe members (or anybody else, but in this case with referencing to FIX standard document) can answer for folowing question:

- Is it possible to change SenderCompID and/or TargetCompID during estabilished FIX session?

Thanks anyway.

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**Author:** ![fplpo\_x](https://avatars.discourse-cdn.com/v4/letter/f/7ab992/32.png) [@fplpo\_x](https://forum.fixtrading.org/u/fplpo_x)\
**Post date:** [March 23, 2000, 8:54pm UTC](https://forum.fixtrading.org/t/changing-of-compid/3815/3 "2000-03-23T20:54:00Z")

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[original email was from Ryan Pierce - [rpierce@taltrade.com](mailto:rpierce@taltrade.com) ]  
\> Does anybody of FIX committe members (or anybody else, but in this case with referencing to FIX standard document) can answer for folowing question:  
\> - Is it possible to change SenderCompID and/or TargetCompID during estabilished FIX session?

I’m not sure if this is directly addressed by the spec, but all standard business practices that I’ve seen indicate that no, SenderCompID and TargetCompID DO NOT change during the session.

Fields such as SenderSubID and TargetSubID as well as DeliverToCompID and OnBehalfOfCompID and their related SubID fields DO change during a session.

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**Author:** ![lindawoods11\_x](https://avatars.discourse-cdn.com/v4/letter/l/b3f665/32.png) [@lindawoods11\_x](https://forum.fixtrading.org/u/lindawoods11_x)\
**Post date:** [May 8, 2000, 5:04pm UTC](https://forum.fixtrading.org/t/changing-of-compid/3815/4 "2000-05-08T17:04:00Z")

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Under the section Session Protocol - Standard Message Header there are examples of how the SenderCompID, TargetCompID, OnBehalfOfCompID and OnBehalfOfCompID DO change during a single FIX session between multiple firms.

\> \> Does anybody of FIX committe members (or anybody else, but in this case with referencing to FIX standard document) can answer for folowing question:  
\> \> - Is it possible to change SenderCompID and/or TargetCompID during estabilished FIX session?  
\>  
\> I’m not sure if this is directly addressed by the spec, but all standard business practices that I’ve seen indicate that no, SenderCompID and TargetCompID DO NOT change during the session.  
\>  
\> Fields such as SenderSubID and TargetSubID as well as DeliverToCompID and OnBehalfOfCompID and their related SubID fields DO change during a session.  
\>  
\>