Wow that's amazing I heard something like that before but never really looked into it. In the uk you are taxed the same no matter when you buy or sell. I should seriously think about moving my shares to a US brokerage and moving to the states for a year just to get the lower tax rate.
Well, for now the long term capital gains rate for those in the top tax bracket is 20%. But there's also a net investment income tax of 3.8% for high income earners that was included in the Affordable Care Act (aka ObamaCare). Then, depending on the state, there is state level taxation of capital gains.