Simple Truths about High Frequency Trading

The interest in High Frequency Trading, of HFT for short, comes from how it combines finance, technology and secrecy. The press around the subject has increased dramatically as Michael Lewis has been promoting his new book on the topic, Flash Boys.  A chapter appeared in the NYTimes that is well worth the read. Discussions around the issue made CNBC's daytime market coverage look very similar to Fox News (because of the yelling and screaming, not because of any right wing agenda).  In the midst of this uproar, the high frequency trading firm Virtu has delayed their IPO.

Michael Lewis is a good author, but he likes to tell narrative stories with good guys and bad guys. And as Tyler Cowen once said, "As a simple rule of thumb, just imagine every time you’re telling a good vs. evil story, you’re basically lowering your IQ by ten points or more."  So without getting into some of the more esoteric details, what's really going on?

1. The market has always needed intermediaries, the people who help connect buyers and sellers when they don't want to buy and sell at exactly the same time. These intermediaries need to make money. Without some money being paid to liquidity providers there will be no liquidity.

2. As floor traders have been replaced by computers running algorithms, spreads have narrowed. Investors spend significantly less money getting into and out of positions compared to 10 or 15 years ago.

3. HFT firms attempt to front run large traders. Any market intermediary needs to try to get out of the way of big buyers after the shares they have offered to buy or sell have been taken because if they didn't they would go out of business very quickly. But HFT set ups allow them to pretend there is are more shares available to be bought or sold in the market than there actually is which can be quite frustrating for those trying to execute large trades.

4. Googling "backing away" shows that intermediaries have been causing issues well before they consisted of the population labelled as "high frequency traders".

5. The ones losing the most money from high frequency traders are those attempting to trade large amounts of stock on the market. These are institutions such as mutual funds, pension funds and hedge funds.

6. While the situation remains annoying to institutions, HFT volumes and profits have actually been falling over the past few years. 

Wall Street rips people off all the time, but there seems to be more of an outrage when the people making money are outsiders and the people losing money are closer to being insiders. 

HFT firms have been the best customers of many of the exchanges - they pay high fees to get their servers situated next to the exchange and provide large amounts of volume to the exchange. In an effort to increase their profits from HFT traders many of the exchanges have implemented some trading rules that benefit HFTs at the expense of other traders on the exchange. Michael Lewis's story explains how some large institutional traders have figured out how they are being taken advantage of and are turning to people such as the IEX Group (The "good guys" in his book) in order to trade without having to worry about people gaming the system. 

Exchanges are going to have to reevaluate their own systems and make them more favorable to institutions that engage in relatively simplistic trading if they want to be profitable in the long run. (Part of this also involves setting up incentives for market makers which reduce the probability of future flash crashes, but that's a much more complicated subject).

If you are a retail investor, the hubbub over HFT shouldn't matter that much to you. You are getting better execution than you ever did under a system managed by human market makers. HFT traders are small parasites that have outcompeted bigger parasites. Overall they've been a net benefit to the ecosystem.  

And it is worth keeping in mind that the impact of HFT firms is small compared to other financial players. The only surprising thing about revelations that many large banks have been manipulating numbers they trade in both the interest rate and foreign exchange markets is that they finally got caught. And the additional 0.1% market impact that HFT firms might cause on large trades is very small when compared to the 5.1% average commission that Real Estate brokers take in on every transaction they make.  The HFT story is smaller than it looks.