I guess we have to agree to disagree. Unless all countries agree to a world-wide transaction tax, it will fail as investors will simply move their funds to markets that do not have this tax. Ask the country of Sweden how their transaction tax worked. Not only did they fail to raise revenue, most of their prior volume left for London which had a much less onerous transaction tax than Sweden.
I find it interesting that people like to criticize speculators and high frequency traders the second the market starts going down. Why was there no criticism of speculators and high frequency traders in late March 2009 through the rest of 2009 when the market took off?