&gt;What you haven&#x27;t made clear is why you believe you&#x27;re actually arguing with anyone here. I am 100% certain, because I&#x27;ve had the conversation with him multiple times, that &#x27;kasey_junk agrees with you that there is such a thing as malignant electronic trading.<p>I was arguing that sub-second algorithmic trading cannot be credited with substantially reducing spreads in the early 00s.<p>kasey_junk linked to an article that claimed that.<p>It&#x27;s a defense of HFT that&#x27;s rolled out so often that it&#x27;s practically become a cliche.