Marshall Wace has accused rival hedge fund Citadel of making excessively broad and burdensome demands for documents as the two firms continue to clash over the recruitment of former Citadel portfolio manager Daniel Shatz, according to a report by Bloomberg.

In a filing with a New York court on Tuesday, Marshall Wace argued that Citadel is seeking unnecessarily extensive searches using terms that are “highly common”, while declining to engage in what Marshall Wace described as meaningful discussions about narrowing the scope of its requests.

The dispute stems from an arbitration case between Citadel and Shatz, who joined Marshall Wace in 2024 as the firm’s global head of credit. Shatz alleges that Citadel withheld an eight-figure deferred compensation award after his departure, claiming the decision was retaliation for concerns he had raised about potential securities violations.

Citadel, however, maintains that Shatz breached his employment agreement by taking confidential information before leaving the firm and has sought access to communications and other records held by Marshall Wace as part of the dispute.

A New York judge ruled in June that Citadel could subpoena Marshall Wace records relevant to the arbitration. The ruling followed an effort by Marshall Wace to block the subpoenas, with the firm arguing that Citadel was using the discovery process to harass a competitor.

The court determined that much of the information sought by Citadel was relevant, including communications between Shatz and Marshall Wace concerning the construction of a new credit team.

The latest filing follows a further application by Citadel earlier this month accusing Marshall Wace of failing to comply with the court's order. Citadel also asked the court to clarify that Marshall Wace executives Anthony Clake and Alan Hofmeyr fall within the scope of the subpoenas and sought to broaden the search terms used to identify potentially relevant documents.

Marshall Wace has rejected those requests as “premature, unnecessary and unwarranted”, arguing that they are diverting resources from the existing discovery process.

A Citadel spokesperson said the firm expects Marshall Wace to comply with the court's order and produce the requested emails.

Marshall Wace said in Tuesday's filing that its document production should be completed shortly and that it intends to “fully comply” with the court's order.

Citadel has previously alleged that Marshall Wace has spent months delaying access to evidence, while Marshall Wace has disputed that characterisation and objected to the breadth of the searches being demanded.