An anonymous reader writes: Barclays, one of the biggest banking and financial services firms in the world, has sold its business on the floor of the New York Stock Exchange to Global Trading Systems. This is significant because it marks a transition between human-based trading and high-speed trading. Now, humans on the NYSE floor have more of a supervisory role, making sure the automated systems don't go haywire. Barclays has been around for hundreds of years; GTS was founded in 2006. "There used to be dozens of specialist firms, as designated market makers were once known, at the NYSE floor. But profits from trading U.S. stocks dwindled, making it difficult to serve as market makers without automation. Although GTS, Virtu, IMC and KCG employ human traders at the floor, their businesses are driven by some of the industry's most sophisticated computer systems."