Citadel has accused Marshall Wace of stonewalling by failing to comply with a court order to produce documents related to the recruitment of former Citadel portfolio manager Daniel Shatz. A New York judge ruled in June that Citadel could subpoena records from the British hedge fund group as part of an arbitration dispute with Shatz, who alleges he was denied deferred compensation from Ken Griffin’s firm. Citadel claims Shatz stole confidential information before his 2024 move to Marshall Wace to serve as global credit head.

The dispute highlights intense competition for talent among major hedge funds and the legal battles that often follow high-profile departures. Both firms are known for aggressive protection of intellectual property and compensation structures. The arbitration proceedings continue as Citadel seeks to enforce the subpoena and obtain evidence supporting its trade secret allegations.