US taxpayers are required report all their world wide income. Being a shareholder of any business domestic or foreign living in the US or abroad does not subject anyone to pay a US Income tax regular or increased. The US tax is an INCOME tax so the criteria is not ownership but was there any income as a result of the income, i.e. dividends etc. and if foreign tax was paid on that income then the Foreign Tax Credit can be used.

Individual Americans abroad, who are shareholders in their small business corporations, are now subject to at least triple taxation on their active business income! Read this article: www.taxconnections.com/taxblog/seriously-now-whos-gilti-senators-wyden-and-brown-attempt-to-reinforce-the-punishment-of-gilti-americans-abroad/