Regarding Expat Americans being subject to U.S. Taxes, the gentleman above is sort of correct. As an American citizen, you always have to file but if you actually reside outside of the U.S., you may be eligible for the foreign earned income exclusion (first $84,000 of foreign earned income is excluded from taxation for overseas residents). In addition, if you are residing in a country that taxes your income, you may be eligible for a credit for foreign taxes paid if that country has a tax treaty with the United States. I'm not sure if Hong Kong has a tax agreement with the U.S. or not but as with anything else concerning U.S. tax law, it can get complicated and it might be worth your while to research the issue to see exactly how you would be impacted by the various scenarios that you are researching.