Renaissance? What is that...?
Founded by Jim Simons, the "Father" of quantitative research. The firm is famous for their significant year-over-year returns and notorious for only hiring PhDs from mathematics/physics/computer science.
There is an interesting book on how Jim Simons created the company and built his team of academics from the ground up, "The Man Who Solved the Market"
I don't understand why I was downvoted? I don't think there was enough context for anyone (who's not in the field) to know what you meant, and I thought it would be useful for people like myself to get clued in.