Good question!  I don&#x27;t have an answer to that.  I do know that the markets survived just fine before the HFT companies came along, and now that they&#x27;re here, I don&#x27;t see society as a whole any better off for their presence.<p>Maybe, without just saying &quot;they provide liquidity&quot; and leaving it at that, you can explain how the post-HFT world is better for anyone but the HFT companies?