In a recent episode, the ever-brilliant Planet Money podcast looked at the arcane world of high-frequency trading. The usual clarity of exposition was further enhanced by something of a Mule theme. It seems that Planet Money host Chana Joffe-Walt is, like me, a Tom Waits enthusiast and she found a way to fuse “Whats He Building in There?” from the Mule Variations album with the otherwise non-musical subject of the podcast. An inspired choice.
So, what is high-frequency trading? Here is how Planet Money describes it.
In high-frequency trading, people program computers to buy and sell stocks in quick succession under certain, pre-defined circumstances. The idea is to profit from fleeting changes in the price of a stock.
This type of trading is made possible by the increased use of electronic trading platforms for financial markets around the world and is a special case of so-called “algorithmic trading” (or “algos”). It has been estimated that as much as 75% of the trades on the New York stock exchange were generated by algos and perhaps 50% on some European markets.
High-frequency trading has been generating some controversy in recent years:
High-frequency traders often confound other investors by issuing and then canceling orders almost simultaneously. Loopholes in market rules give high-speed investors an early glance at how others are trading. And their computers can essentially bully slower investors into giving up profits — and then disappear before anyone even knows they were there.
Critics of high-frequency trading argue that it is a form of front-running, a practice which is illegal in most jurisdictions. The counter-argument in defence of the algos is that it increases the efficiency of the market. As Steve Rubinow of NYSE Euronext explains to Planet Money:
Every innovation of this type makes the market more efficient. … The faster we trade, and the more people you have trading, any aberrations that exist in the market are taken out of the market really really quickly, which makes for a fairer market for all participants … Those prices are about as fair as they could be.
Efficient markets are a good thing and I have used a similar argument here on the blog to defend short-selling. Nevertheless, there has always been something about high-frequency trading that makes me uneasy. In an interview with Edge, Emanuel Derman seems to put the finger on the source of this unease:
Also, people who benefit from it tend to over-accentuate the need for efficiency. Everybody who makes money out of something to do with trading tends to say, oh, we’re got to do this because it makes the market more efficient. But a lot of the people who provide this so-called liquidity and efficiency are not there when you really need it. It’s only liquidity when the world is running smoothly. When the world is running roughly, they can withdraw their liquidity. There is no terrible need to be allowed to trade large amounts in fractions of a second. It’s kind of a self-serving argument. Maybe a tax on trading to insert some friction isn’t a bad idea, just as long term capital gains are taxed lower than short term gains.
Derman started working as a “quant” in financial market around 25 years ago and had a long stint at Goldman Sachs. His response is not likely to be one of knee-jerk suspicion, but rather the considered voice of experience.
Joffe-Wolt’s reinterpretation of Waits conjured up an atmosphere of mystery and fear when exploring NYSE Euronext’s new data centre. Perhaps a bit of fear of high-frequency trading is healthy.
Image Source: Discogs