In this video, Professor Larru explores the significant role of high-frequency trading (HFT) in modern financial markets. He explains that HFT uses computers to execute trades at extremely high speeds, accounting for a substantial portion of trading activity in both equity and US markets. Professor Larru delves into various HFT strategies, such as market making, algorithmic execution, and statistical arbitrage, highlighting how these strategies enhance market efficiency but can also be predatory.