&gt; they never seem to answer the question of why someone who is not an HFT firm would want to trade on an exchange that caters to high frequency traders.<p>There are network effects in trading: people go to transact where everyone else is transacting. Because HFT is allowed on the most popular venues, the economic thing to do is hold your nose and trade there too. This is true even if HFT somehow makes the venues &quot;worse&quot; (which it doesn&#x27;t).