WHEN MUST THIS FORM BE FILED? It should be filed when you own a foreign mutual fund (not sold in the US securities market) or you own a foreign corporation that as a major portion of its activities invests in foreign equities, foreign mutual funds and other foreign investments. This form does not need to be filed is you merely own actual foreign stock certificates, or shares in a foreign corporation that does not produce passive investment income.
Form 8621 is filed annually with your personal tax return. A separate Form must be filed for each separate foreign mutual that you own. If the foreign mutual fund is held in your US stock brokerage account, you do not need to file this form. See The Form 8621 here. Though it appears simple, this form is difficult to complete correctly. Let us know if you need help.