stabblerpie

>This also seemed to me an example of the opportunism of HFT, where the HFT shaves the spread by a penny or two during calm markets, but withdraws (and exacerbates issues) during volatile and troubled markets, which seems to me the point in time at which liquidity provision is most valuable.

HFTs thrive in volatile markets. not calm markets. Those HFT firms that stayed in the market during the flash crash made a killing.

>Any HFT who hunts for a sure thing isn't making any money - there are far more 51% gain, 49% loss opportunities than there are sure things.

There may be far more 51/49 opportunities. However, saying that HFTs hunting for sure things isn't making money is far from true.

I worked for a UHFT firm that had a winning percentage of more than 95% of the time. The 5% losers had VERY small losses too. All arbitrage trading. Not market making like everyone seems to be focused on in here.