Investment Technology Group, Inc.
A financial technology and brokerage firm that builds electronic systems for big institutional investors — pension funds, mutual funds, and hedge funds — to trade large blocks of stock. Its signature product was POSIT, one of the industry's first anonymous "dark pool" matching systems, which quietly paired up buyers and sellers so a huge order wouldn't move the market against them. Founded in 1987 as a division of the investment bank Jefferies, it went on to run as an independent public company before being folded into Virtu Financial in 2019.