Do I need to report taxes to the U.S. Internal Revenue Service?

If a valid W-8 BEN is filed for the account, the Internal Revenue Service only withholds a small amount of tax on dividends received. The rate varies from country to country but it does not exceed 30%. 

Investors are responsible to report any capital gains or capital losses to your local tax authorities. However, a separate tax return is not required to be filed in the United States. A Form 1042 is mailed to you during tax season.