The new rate of 18 per cent, which will come into effect from 6 April 2008, is forecast to benefit 80,000 investors in 2008.
Darling added that 90 per cent of investors will continue to pay CGT at the low rate of 10 per cent.
Calling for "a competitive and simplified tax regime", Darling will reduce corporation tax to 28 per cent in the year beginning 6 April 2008.
He also revealed a pared down taxation structure for smaller firms, with a corresponding 60 per cent increase in the funding available through the small firms loans guaratee, to be implemented over the course of the next year.
