Are you sure you pay 50% in tax on the profits? A quick google suggests that 50% of the profits counts as income, which is then taxed at your income rate. 50*50 = 25% in the top bracket.
In the US long-term cap gains is 0%, 15%, or 20% - not far off from 25%.
In the US long-term cap gains is 0%, 15%, or 20% - not far off from 25%.