# How to complete Tax form Mod.21-RFI



## ivorystraws (13 Jan 2009)

Hi,

I'd just like to get some advise/experiences tax form about witholding tax!? I have invoiced a company based in Portugal and they want me to complete a tax form - Mod 21. I don't understand why or what the reason for this is since I have invoiced other companies in other European companies who did not require this.

Can anyone shed some light on this please?


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## abilca (14 Jan 2009)

Hi back,

That's because different coutries have different treaties.  Portugal is one of the countries that requires a MOD 21 to be compleated and signed by you or your company.  Also, if you are from the US, the MOD 21 needs to be authenticated by the Internal Revenue.  Also, keep in mind that treaties change constantly so you can always ask the IRS about it.


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## ivorystraws (14 Jan 2009)

Thanks Abilca! It's just that I've never encountered it before. So once I complete the form, I should be totally exempt from Portuguese withholding tax? i.e. Does Ireland have an agreement with Portugal for the Avoidance of Double Taxation.


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