The Impact of the Tobin Tax in a Heterogeneous Agent Model of the Foreign Exchange Market

We explore possible effects of a Tobin tax on exchange rate dynamics in a heterogeneous agent model. To assess the impact of the Tobin tax in this framework, we extend the model of De Grauwe and Grimaldi (Eur Econ Rev 50(1):1–33, 2006) by including transaction costs and perform numerical simulations. Motivated by the importance of the market microstructure, we choose to model the market as being cleared by a Walrasian auctioneer. This setting could more closely resemble the twolayered structure of foreign exchanges at daily frequency than a price impact function, which is often adopted in similar studies. We find that the Tobin tax can deliver a moderate reduction of return volatility and kurtosis. In addition, simulations indicate that the Tobin tax reduces the degree ofmispricing in the time series, which is primarily achieved by eliminating long-lasting deviations from fundamental value.