According to an HFMWeek source close to Ken Griffin's firm, people of all levels joined in sales and trading along with investment banking roles.

The influx of new staff comes as high-profile names at the organisation depart. Todd Kaplan, the head of its investment banking business, and Stuart Kaperst, a managing director of Citadel's investment bank, both departed the firm this month after less than a year. Meanwhile, late last year, Rohit D'Souza, who was hired as CEO of Citadel Securities, and Peter Santoro, who ran the institutional trading business, also left the firm.

According to reports, one of the most recent hires for Citadel Securities is Art de Pena, who joined this month from Royal Bank of Scotland as a managing director in loan sales for the hedge fund's credit business.

Although Citadel Investment Group is pushing to expand its investment banking business, it has also made hires in other divisions. Most recently, Jake Walthour joined this month as head of US distribution for Citadel Asset Management. Walthour co-founded Aksia, a New York-based investment consulting firm.