http://www.itinagent.com | Is there a way IRS may know about my foreign shareholding if I don’t file Form 5471?
Though in the past it has been difficult to secure ownership information on Foreign corporations, in the future it will become easier. The IRS is actively involved in securing more information of US citizens finances overseas, and will only increase its efforts in the future. There are many US-Foreign Country tax treaties which do provide for complete cooperation between the two nations with respect to the exchange of tax information on citizens domiciled in each.
If you own part or all of a Foreign corporation, and have not filed form 5471, you should start filing it immediately to avoid the $10,000 penalty.