The Man Group has identified the employee arrested on Wednesday on suspicion of insider trading.
Carl Esprey, a portfolio manager at GLG Partners, was among three men taken into custody for questioning by the Financial Services Authority and then released. He has been suspended.
Esprey has been a portfolio manager at GLG since 2008, two years before it was acquired by Man. His FSA registration became inactive on Wednesday. Prior to joining GLG, he worked at mining company BHP Billiton's corporate finance department.
Esprey, 33, was the youngest man arrested Wednesday. The others have still not been identified, and are 37 and 39 years old.
Man said yesterday that it is cooperating with the FSA investigation and that the probe is into Esprey's actions "as a private individual and not as an employee of Man or GLG."