Over the past decade or so there has been debate over the introduction of a Tobin tax to forex. This would be a tax added to every fx deal that would essentially make prop trading unfeasible and its aim is to stop the banks trading fx and supposedly wrecking economies etc. It has never been adopted for many reasons two of which are that some country is always bound to not apply the tax to attract business and the banks would trade fx futures where there is no actual delivery of the currency and call the trade something else.
