Really, high-frequency trading is the most common sort of trading? That is absolutely astonishing. Do you think that says anything about how much stock (by valuation) is invested long-term?
Even if, say, 95% of stock is held in long-term investments, high-frequency trades will dominate the metric "% of trades executed", since high-frequency trading holds the stock for less than 1/20th of the time long-term trading does.
Suppose num_long shares of stock are held in long-term investments, as a permanent feature of the economy. Suppose further that the average duration of a particular long-term investment is two years. Then every two years, num_long trades will occur under the banner of "long-term investing".
Suppose num_hft shares of stock are held in HFT investments, and that the average duration of an HFT investment is one day. Then every two years, 730.5 * num_hft trades will occur under the banner of "high-frequency trading".
But who cares what the % of trades are? They don't get more weight as a stakeholder because they are trading a lot. In fact they have absolutely none, but that doesn't diminish the control held by the 95%.
