Arbitrage. Buy something cheap on one exchange and sell it higher on a different exchange. The trader with the lowest latency gets a big chunk of the market jus

Arbitrage. Buy something cheap on one exchange and sell it higher on a different exchange. The trader with the lowest latency gets a big chunk of the market just by being fast. You get even more if the algorithm has any ability at all to predict the future. The average profit per transaction will be small, but you get 10 million opportunities a day to repeat it.