Quote from PlusMinus:
This will not only hurt active traders (individuals), but hedge funds, which happen to heavily trade for pension fund clients. The problem with this tax, like almost all taxes, is that the consequences are impossible to predict.
Hedge funds can always trade swaps and skip the tax. Basically what they do in the UK. Feed off the market maker exemption. And if there is no market maker exemption, watch the US market to lose share to Hong Kong -- and I mean a massive relisting of companies.