The difference is that individual investors will often hold on to their shares for months or years, rendering the trading tax insignificant.<p>The tax is targeting (very) short-term professional traders, selling and buying back shares multiple times a day (or per second, in some cases). This type of trading adds little value to the useful allocation of capital, and imposes a &#x27;tax&#x27; on other traders.<p>To me, that sounds like as good a thing to tax as any. Besides, I&#x27;d guess that implementation of such a tax would be relatively straightforward, as far as taxes go.