Between 2000 and 2003 Aberdeen used an employee benefit trust (EBT) to pay senior directors, with around £31m thought to have been free of income tax and national insurance.
In a Scottish Court of Session hearing, HMRC won an appeal that tax and national insurance of £7m should have been paid on bonuses which were later converted into shares.
The rules over EBTs were changed in 2003 to make them illegal, however the appeal was based on whether the structure was appropriate prior to this point.