All unrealized capital gains are also taxed upon giving up citizenship. Furthermore, one still pays U.S. Estate taxes on what one has left upon death, no matter

All unrealized capital gains are also taxed upon giving up citizenship. Furthermore, one still pays U.S. Estate taxes on what one has left upon death, no matter how many years in the past one gave up his or her citizenship. Currently, Federal estate tax is 40% (there is also state estate tax up to 20%). You also are not allowed to spend too much time back in the US once you have relinquished citizenship without triggering US income taxes again.