You may be right about Swissquote.
I went to their website and probed their account-opening procedure.
Before I got started, I encountered this page (click the image to enlarge it):
I continued to the application pages, filling in personal data, including: Nationality - United States, and my residence address in the United States. Swissquote accepted this portion of the application. So far, so good.
I stopped short of giving Swissquote my tax I.D. information. Having refused to provide that information, I was not able to continue.
Before deleting all the information I had already filled in, and exiting the site, I took a screen-shot of this "Declaration" (as before, click the image to make it more readable):
It's interesting that Swissquote makes a point of saying:
(1) that they do not advertise in the U.S. market, and they do not solicit U.S. clients, but
(2) if you are a U.S. client of Swissquote, they will hand all your information over to the IRS