Man Group faces a potential $155m payment after a London judge found two of its subsidiaries liable in a corruption case involving Kuwait's state pension fund, sending its shares down as much as 5.9%, according to a report by Bloomberg.

The ruling follows a year-long civil trial into allegations that Fahad al Rajaan, the former director general of Kuwait's Public Institution for Social Security (PIFSS), received illicit payments from financial institutions seeking investment mandates. The wider scheme allegedly diverted approximately $1bn from the pension fund over several decades.

Judge Richard Jacobs found that two former Man Group employees were aware that an intermediary was paying bribes to al Rajaan, making two of the firm's subsidiaries liable alongside other defendants. The court indicated that PIFSS could recover approximately $155m from Man Group, although the final amount remains subject to a further hearing in November and adjustments relating to settlements reached with other parties.

The proceedings also examined an internal compliance review conducted during the tenure of current chief executive Robyn Grew as global head of compliance. The judge criticised the review for confirmation bias after it cleared the individuals involved and allowed the relationship with the intermediary to continue, although Grew herself was not directly criticised.

Former Man Group Middle East head Antoine Massad was also found personally liable, with the judge concluding that he knowingly participated in the bribery arrangements. Former chairman Lord Stanley Fink provided evidence supporting Massad's character, but the court rejected Massad's account of events.

Man Group disputed the ruling, describing the case as a legacy matter relating to a contract terminated more than 30 years ago. The firm said the findings did not reflect its business practices and confirmed that it was evaluating its options, including a potential appeal.