Complex sentence: Levin has been in and around the S&P 500 futures pit at the CME for 21 years, where he started as a runner for Lind-Waldock in 1989.
Split into simpler sentences: Levin has been in and around the S&P 500 futures pit at the CME for 21 years. He started there as a runner for Lind-Waldock in 1989.