&gt; Most HFT strategies don&#x27;t actually do this. Buying and selling in such a short period implies a pure arbitrage, of which there are very few. The ones that do exist are generally fully exploited by the single fastest participant.<p>I assumed most were of that sort. I still fail to understand what does being one millionth of a second faster accomplish if you&#x27;re going to hold your position longer than that. It still triggers a competition for being the fastest participant that makes the transaction right after an event.<p>&gt;Why? Automated market-makers are a middle-man that temporally bridge supply and demand between &quot;real&quot; buyers and sellers. Kind of like a grocery store temporally bridges supply and demand between consumers and farmers. Kind of like a car dealer temporally bridges supply and demand between consumers and manufacturers. Kind of like... you get the idea. Why are equity markets different?<p>That&#x27;s an interesting thought. It may just be that the subject has a lot more elements that I haven&#x27;t considered yet.<p>Here&#x27;s something for you to consider and I would love to hear your POV on this. What if the regulators decided to ban all HFTs. Transactions had to rate limited by 300ms or more. In your opinion, would the markets behave any differently from now? If not, then what is being gained by all the major investments in HFT systems and platforms? If yes, then what do the markets gain?