Just transaction tax everything, in an inversely scaled amount to the time between you buying/selling that same kind of item.
So if you buy, buy, buy, wait a month, then sell, sell, sell, you don't pay much/any transaction tax.
But if you buy, sell, buy, sell, buy, sell, you get transaction taxed to extinction.
Now make it so you publish your sell price for a whole hour, before you finalize trades for it.
Now make it so that you cancel too many sell orders, compared to those that made it to the end of the hour but may (or may not) not have receive any buying offers, you get a charge applied.
Now make it so that the all buyers making offers get a pro-rata split of the shares being sold.
Now increase transaction taxes when the number of shares in the selling order is lower than the number of buyers. An exercise for the sell to predict how large in volume the sell order needs to be to not get penalized here.
All this to take the money out of the transaction part, and place it back into the, I'm holding this stock, so I'm taking a risk the business will do well in the future, compared to holding cash.
So the next question, who gets to spend the transaction taxes and on what ? Government coffers, as the people effectively permit this activity to go on under the protection of the state. Other suggestions ?