Market-makers often describe a rough-and-tumble trading venue as a “shark tank” – a place where hyper-evolved predators circle, waiting to take a chunk out of a dealer’s profits.

The analogy can be pushed a bit further, too. Sharks have a famously keen sense of smell, and some of the predators dwelling in modern venues work by detecting bank algorithms and anticipating their behaviour – forcing the price away from the bank and gobbling up its spread. Dealers know these dead-eyed automatons as