In the days of fighting sail, the ship’s main armament typically consisted of rows of cannons lined up on each side of the ship. These cannons fired through ports in the side of the hull and were mounted on wheels so that they could be pointed and able to recoil when fired. Normally, they were constrained by heavy ropes. But from time to time one or more would get loose. Each cannon could weigh as much as three tons and would then roll around the gun deck as the ship pitched and rolled, crushing anything or anybody in its way. The gundeck would be crowded most of the time – each gun on a large ship had a crew of 14 men who not only worked but ate and slept near their gun. Needless to say, a loose cannon could do much more damage than any broadside from an enemy ship.
In the market, the black boxes or “algos” are the equivalent of the loose cannons of yore. They are out of control and roll around in herds, as many of them share similarly programmed rules. You can watch the “herding” in the stock market by watching the “Tick” as it moves to extremes in both directions – that’s the herd. You hear about “flash crashes” – that’s a herd of algos running over some security or asset class. They pose a huge danger to the financial system, and need to be reined in. The mistake that the regulators make is to only consider them as single entities, without comprehending the emergent phenomena arising from unintentional herding behavior.
Financial Reality 