NEW YORK, June 26 (Reuters) - U.S.-based hedge fund Bridgewater Associates said on Monday it had appointed Margo Cook, currently an outside director and former president of Nuveen Advisory Services, as co-chair of the firm's operating board.

Cook will join Mike McGavick as a board co-chair, the hedge fund said in a statement. Bridgewater's operating board is responsible for overseeing the firm.

Ray Dalio, the billionaire investor who built Bridgewater into one of the world's biggest hedge funds, last year transferred control of the firm to the operating board.

Cook, who has more than 30 years of experience in the asset management industry, joined Bridgewater as an independent board member in July 2021.

Before that, she spent more than 11 years at Nuveen, where she was the president responsible for $1 trillion in assets. She also previously worked at Bear Stearns Asset Management and BNY Mellon. (Reporting by Carolina Mandl in New York; Editing by Leslie Adler and Jamie Freed)