Fawaz Al Hasawi and the Al Hasawi family took over at Forest in the summer of 2012
Nottingham Forest have been ordered to pay former owner Fawaz Al-Hasawi £4.2m after losing a legal fight relating to the sale of the club.
Evangelos Marinakis took over in May 2017, with debts of £40m owed to Forest's former parent company and an ex-director written off in the sale.
The club said the dispute relates to "detailed accounting evidence and the interpretation" of the purchase.
Forest say they may seek clarification and appeal against the decision.
In his High Court ruling on Friday, Judge Stuart Isaacs QC said Al-Hasawi, who was part of a family consortium which bought the Reds in 2012, "invested heavily" in the club's training ground, academy and match day facilities at the stadium.
Forest, managed by former Republic of Ireland boss Martin O'Neill, finished the 2018-19 season - the second under the ownership of Marinakis - ninth in the Championship table and eight points adrift of the play-off spots.
The Reds said the payment will have "no bearing on the long-term position of the club or its ability to operate".