Against a financial transactions tax

Maria Coelho, job market candidate at UC Berkeley, studied this topic and came up with this:

This paper analyzes the effect of the introduction of financial transaction taxes in equity markets in France and Italy in 2012 and 2013, respectively, on asset returns, trading volume and market volatility. Using two natural experiments in a difference-in-differences design, I identify bounds on elasticity estimates for three categories of avoidance channels: real substitution away from taxed assets, retiming (anticipation of transaction realizations and portfolio lock-in), and tax arbitrage (cross-platform and financial instrument shifting). I find large responses on all margins, that account for significantly lower revenues than projected. By far the strongest behavioral response comes from high-frequency trading lock-in on regulated exchanges, with a high tax elasticity of this type of turnover in the order of -9. The results shed light on overlooked features of optimal FTT design, suggesting they may be poor instruments for both revenue-raising and Pigouvian objectives.

The paper is called “Dodging Robin Hood.”  This is consistent with earlier findings on Sweden’s transactions tax, and that proposal continues to be one of the more overrated ideas in American Progressive political discourse.