http://premarketinfo.com/2012/12/11...of-everything-that-is-wrong-with-our-markets/ A Five Minute Example of HFT Shenanigans I was trying to buy 500 shares of a preferred stock this morning, Principal Financial Group Inc. series B (NYSEFG-B). It is such a challenge to trade any type of illiquid issue as the execution of orders is nearly impossible in this HFT world. Here is the sequence of events. At 09:39:08, the stock is offered on EDGX at $26.29. I place an order to lift the offer. The shares trade but I get filled on zero shares. Knowing that my bid will cause a bunch of HFT programs to penny-jump me (step ahead of my order by a penny - which they immediately do), I cancel the order. The HFT penny jumper cancels their order as well. At 09:39:29, the stock is offered on EDGX again at $26.32. I place an order to lift the offer. The stock trades at the exact same second. Again, I get filled on zero shares. I cancel the order. At 09:39:41, the stock is offered on PCSE at $26.29. I place an order to lift the offer. The stock trades at the exact same second again, but I get filled on zero shares. I cancel the order. At 09:39:50, I place a hidden order to buy the stock at $26.32. Five second later the stock prints in front of me at $26.33 (Obviously these hidden orders arenât as hidden as they should be). I leave the hidden order to buy at $26.32. At 09:40:05, the stock prints right through my hidden order on another exchange at $26.30. So despite my bid being higher at $26.32, thanks to the fragmentation in the market, I get filled on zero shares again (and the seller gets a worse price!) At 09:40:20, the stock prints through my hidden order again at $26.30. Again, no execution for me. Frustrated, I cancel my order. A few seconds later, at 09:40:36 a couple of HFT programs battle out for the top of the order queue, and the bid changes rapidly, as you can see below: At 09:40:40, the HFT programs go to battle again fighting for the best bid. This battle continues for the next few minutes. In fact, during one period of time from 09:44:53 â 09:46:35 (a total of just over a minute and a half), the best bid changes over 800 times, as these two HFT algorithms battle to be at the top of the queue. At 10:07:14, I finally lift an offer and pay up to $26.35. The HFT firm scalps their few cents from me, and all the games are over. Some serious issues are highlighted in these few minutes of activity: 1) Inability for market participants to access a quote. 2) Excessive quote pollution as HFT algorithms battle each other. 3) Market fragmentation can lead to inferior execution. 4) HFT penny jumping can discourage market liquidity. The bottom line is that all of these issues discourage participants from trading illiquid securities â making these securities even more illiquid.