invented". Once a discovery is made, it continues to exist for good or ill. Some of the Los Alamos scientists behind the development of the first atomic bomb were appalled at what they had created. A few decided the new weapon was so geopolitically destabilizing they passed its secrets to the Russians. By frustrating American military dominance, these scientists brought about nuclear power parity which has prevented it ever being used again after Japan had been blasted to the peace table by the devastating detonations over Hiroshima and Nagasaki. The same is true of high frequency trading. This trading scheme combines powerful algorithms with state-of-the-art fiber optic communications to allow computers within milliseconds to identify and take advantage of price disparities in different markets and make a profitable arbitrage trade. The popular picture of trading floors is still of people in brightly colored jackets bawling and hollering at each other in special pits. How anyone understood anything anyone else was bellowing was always a mystery, as were the elaborate hand signals traders made to their colleagues hanging onto at least two phones in the booths just outside the trading pit. Since 2007, most of this "open outcry" trading has been disappearing from exchanges around the world. The buying and selling moved to traders pushing buttons in front of computer screens. But the continued existence of the human factor meant that anyone who could find a way to react faster to a juicy trading opportunity was going to clean up. And so it proved. High frequency trading (HFT) arrived in 2009. A group of investors spent $300 million laying a 1,331 kilometer fiber optic link between exchanges in Chicago and New York. For $300,000 a month, up to 200 trading firms could have hyper-fast access that shaved all-important milliseconds off orders carried by the normal communications companies. Computer algorithms in each city could trade with each other in the blink of an eye, vacuuming up arbitrage opportunities which the link's builder, Spread Networks, claimed amounted to $25 billion a year. A decade on and HFT systems have only got faster and smarter. They have also become ever more expensive. As the controversial US general George Patton once said, "Battles are won by those who get there fastest with the mostest". In might have been imagined that in America, with its reverence for free markets, HFT pioneers would have been regarded as heroes while those parts of the markets that failed to keep up were regarded with no more than a shrug. But this is not proving to be the case. It costs a fortune to stay in the HFT game and a growing number of investors are balking at the price. What this has meant is that fewer of them are choosing to commit funds to markets where HFT reigns supreme. This has served to reduce liquidity, the key element to well-functioning trading. Without sufficient investors, prices can be distorted and markets cannot efficiently match investors with opportunity. So some markets are introducing "speed bumps" which slow down by a crucial millisecond or two the speed at which trades can be executed. The HFT community is of course crying foul. And anyway, it hard to see how this awesome technology can be "un-invented".
