Only if you have plans to move to the U.S and become an individual taxpayer.If you plan to continue in your country and pay taxes over capital gains in there, you as an individual are only subject to this kind of taxation in your country. If you plan to move to U.S. you should fill the 83b election. In case you dont have an SSN or ITIN, you should fill it with awaiting ITIN in the ITIN field.