Foreign broker-dealers are required to be registered under Section 15 of the Securities Exchange Act of 1934 (the “Exchange Act”) unless they are exempt under the Foreign Broker-Dealer Exemption (Rule 15a-6).
Every broker dealer which physically operates in the US must register with the SEC even if their business is directed only to foreign investors outside of the boundaries of the United States.
Every foreign broker dealer that attempts to market securities to any person in the United States must also register with the SEC. This marketing includes the use of the internet, including blogs, websites, and emails to offer securities to US citizens, residents or companies.
Further information on what foreign broker dealers can do to remain exempt under the Foreign Broker-Dealer Exemption is shown in this post by Matheau J. W. Stout, Securities Lawyer.