And he found that the prices of both the South Korean and the Japanese ETFs were being driven by a single trader at a German bank. Every few days, the German bank trader had a bunch of buy orders to execute, in both South Korea and Japan. He’d make his South Korean purchases before calling it a day, passing the Japan orders off to his Asian colleagues to handle when they awakened in Tokyo. The Jane Street trader could now happily see the pop in the South Korean ETF and buy the Japanese ETF until the German died, retired, or figured out how much his laziness was costing him.
