I searched the forums and read that if you have filed a W8-BEN form you are exempt from capital gains taxes in the US. Some of those posters were Australians who stated that they pay no withholding tax for capital gains in the US. But I did a bit research and found this Tax Treaty document from the IRS which details the tax considerations for all treaty countries. If you flip to page 33 you can see that Australia has a 30% capital gains tax...? http://www.irs.gov/pub/irs-pdf/p901.pdf Can anyone shed some light on this issue for me? Does that mean that your broker (say, IB) will withhold 30% of all Capital Gains and send that to the US treasury? Or am I understanding something wrong? Thanks for your help.