By Julie Schlosser

(FORTUNE Magazine) – New York City Founded 1999

Richard Korhammer thinks of himself as a cable provider to Wall Street. He's not dishing up HBO or Cinemax, though; the 38-year-old engineer is working to bring together the nation's electronic exchanges (from Nasdaq to Archipelago) under one box. When Korhammer, who got his start working for Steve Jobs at Next, began consulting for investment banks in his mid-20s, he realized the key strength of the financial markets--efficiency--was lacking in the electronic-trading world. "People purchasing Nasdaq-listed stocks were not able to get the best prices, because they had to use different systems that weren't linked well," he says. He and his partners came up with aggregation software and founded Lava. The company survived 9/11--it was located in the North Tower and everyone managed to escape unharmed --and has gone on to thrive. Some 100 customers, including 15 major investment banks, go through Lava's system to make trades, and the company handles 15% of Nasdaq's traffic. Next month Lava will add foreign-exchange trades to its portfolio. --J.S.