A well-designed Financial Transaction Tax collected on each sale or purchase of stocks, options, and derivatives (also called a "speculation tax") would raise significant revenue and has the potential to restrain the growth of speculative and high-frequency trading in our financial markets.
A similar tax was in effect from 1914 to 1966. A 2009 joint report from the Center for Economic and Policy Research and the Political Economy Research Institute ("The Potential Revenue from Financial Transaction Taxes", Baker et al.) estimated that today such a tax could raise up to $350 billion annually.