Why Are Americans Not Included in the Panama Papers?

http://www.nbcnews.com/storyline/panama-papers/why-are-americans-not-included-panama-papers-n551081

There are numerous other firms, large and small, American and foreign, that help wealthy clients set up offshore shell corporations -- which isn't of itself illegal, as long as the clients aren't trying to hide criminal proceeds or dodge tax collectors, experts said. Mossack Fonseca co-founder Ramon Fonseca has said that his firm broke no laws, and that it wasn't responsible for how the corporations were used.
"This firm is one of thousands in the world and there are hundreds or thousands just like it in the U.S.," said Ana Owens, a tax and budget advocate at U.S. Public Interest Research Group (PIRG), a federation of state-level consumer advocacy organizations. "If a company in the U.S. can do the exact thing for you as this company in Panama, then you might as well do it right here in the U.S. And its perfectly legal, which is the issue."

 See also the USA Today article, which mentions a few U.S. names that have turned up.