You might be surprised by the answer and by the ethics rules that apply. I explain the relevant U.S. rules here.
First, you need to know where to look.
THE USPTO HAS ETHICS RULES AND DISCIPLINES ATTORNEYS WHO VIOLATE THEM.
Many attorneys (that includes many U.S.-licensed attorneys) aren’t aware that the USPTO (a) has ethics rules and (b) disciplines attorneys who violate them. Many American attorneys focus primarily on the Rules of Professional Conduct applicable in the state(s) where they are licensed. But by statute, any attorney practicing before the USPTO is subject to the USPTO Rules of Professional Conduct (see 37 C.F.R. §§ 11.101 et. seq.) and to the disciplinary jurisdiction of the USPTO (see 37 C.F.R. § 11.19(a)). You can read the Rules here.
These rules are enforced by the USPTO Office of Enrollment and Discipline (OED). Sanctions can be severe and include suspension from practice as an attorney before the USPTO. You can find full-text copies of the disciplinary decisions of the OED here.
Another important source of guidance is the Official Gazette. From time to time, the Commissioner for Patents and Trademarks publishes ethics-related “Notices” in the Official Gazette. The 2 Notices most relevant to this topic are here and here.
You can access other Official Gazette Notices here.
So when you comb through all this guidance, what does it say about these international relationships? As far as the USPTO is concerned:
THE CLIENT IS THE TRADEMARK APPLICANT/OWNER, NOT THE FOREIGN ASSOCIATE.
If Juan (an attorney licensed outside the U.S.) contacts Mary (a U.S.-licensed attorney) to file a trademark application for Juan’s client, Fankle, Inc. (also domiciled outside the U.S.), is Mary’s client Juan or Fankle, Inc.? Under U.S. ethics rules, it’s the trademark applicant/owner (Fankle, Inc.), NOT the foreign associate (Juan).
The USPTO was very clear about this in its 1988 Notice:
"In some instances, practitioners deal with a corporate liaison or foreign agent. Such arrangements do not automatically change the person whom practitioner represents, e.g., the inventor or trademark owner. The fact that a U.S. practitioner receives instructions from the inventor or trademark owner through a foreign attorney or agent does not change the fact that the client is still the inventor or trademark owner rather than the foreign attorney or agent." (emphasis supplied)
Significantly for U.S.-licensed counsel, this means the duties they owe to clients flow through to the trademark applicant/owner.
This information was posted on January 6, 2021 and was accurate as of the date of writing. However, the law changes frequently, and readers should not rely solely on general online information but instead should consult a licensed attorney by asking questions about their specific issues when they need legal advice.