Sign up for our COVID-19 newsletter to stay up-to-date on the latest coronavirus news throughout New York Billionaire investor James Simons, of Long Island, is stepping down as chairman at the Setauket-based Renaissance Technologies but will remain on the board of the $60 billion hedge fund he founded nearly 40 years ago. Simons told investors late in 2020 — a year of mixed returns for the firm — that he would be handing the reins as board chairman to Peter Brown, who has been running the company as sole CEO since 2017.