Is it infringement if some steps of a method patent are performed outside U.S. territory?

Hi,

Disclaimer: this isn't legal advice, but only a sharing of general public information.
This is a question regarding high risk that requires an attorney to analyze and advice you specifically about. In general, knowing about a patent and willfully infringing can result in treble damage awards.

Moreover, divided infringement is complicated and the Supreme Court and Federal Circuit just recently decided a case, Akamai v. Limelight, on this issue. The majority opinion held that direct infringement liability of a method claim under 35 U.S.C. §271(a) exists when all of the steps of the claim are performed by or attributed to a single entity (i.e., single entity rule). The actions of one party are attributed to another party under a theory of vicarious liability so as to impose direct infringement liability in at least three different situations, namely, principal-agent relationships, contractual arrangements, and joint ventures. The idea is that if a principal is directing another to contribute to the infringement, then liability can attach.
As you can see from the general information, what you're asking can't be answered on this forum and it requires seeking specific legal advice.

Hope this helps!
Mary