By Mark Thoma
All opinions expressed are his own.
The financial transactions tax is back in the news today. According to reports, French President Nicolas Sarkozy and German Chancellor Angela Merkel will propose a financial transactions tax in September.
Is this a good idea? It would certainly provide needed revenue to cash strapped governments, but at what cost? Governments must raise revenue somehow, but is this the best way to get the cash they need? Some taxes have a large distortionary effect on economic activity -- with a financial transactions tax, the worry is that investment activity will be curtailed-- and others have a much smaller effect. Some taxes can even make markets work better, e.g. taxes that force firms to internalize pollution costs and other externalities improves the decisions firms make. From society's point of view, they are more, not less efficient. Thus, in designing a tax system, we should look for taxes that provide the most revenue at the least cost.
So is a financial transactions tax a highly distortionary, costly tax? The answer is no. The tax would discourage short-term speculative activity, but much of this activity provides little social value. It pushes money around among winners and losers, and traders like it for that reason, but if this activity is discouraged through taxation it would have little effect on long-term investment decisions by firms. For example, one thing this would discourage is high frequency computer trading to exploit minute differences in prices. Does it really matter for long-term investment if these differences persist for a few seconds or minutes more?