It's not a tax, it's the price of immediacy. You can either work your orders yourself (which doesn't in the least require speed), or you can pay a concession. I

It's not a tax, it's the price of immediacy. You can either work your orders yourself (which doesn't in the least require speed), or you can pay a concession. It has always been this way and always will. HFT has made that concession the lowest it has ever been for the vast majority of market participants.