Complex sentence: He then went on to work at the Westport, Connecticut-based hedge fund Bridgewater Associates where he met his future GiveWell co-founder Elie Hassenfeld.
Split into simpler sentences: He then went on to work at the Westport, Connecticut-based hedge fund Bridgewater Associates. At Bridgewater Associates, Karnofsky met his future GiveWell co-founder Elie Hassenfeld.