Some commodities and options exchanges already have fee ranges of that order of magnitude.  They can get away with it because the leverage of the derivatives means the spread is bigger than that.<p>On the equities side, if you went to a dollar per trade it would be priced into the spread one way or the other.  My suspicion would be with decreased liquidity due to participants moving to derivatives that allow for ownership in fractional components of large transactions that make the tax more bearable.<p>Either that, or you wouldn&#x27;t have market makers and the equities market would grind to a halt and things like index funds, etfs, etc would no longer be economically viable.