With 20 games left to play in this season, Juve were third in Serie A, 10 points adrift of leaders Napoli.
The points deduction would push them down into mid-table, outside the spots for European competition.
The ruling is tougher than a nine-point deduction a soccer prosecutor had requested earlier on Friday during a hearing looking at the way Juventus, Italy's most successful club, and a number of other teams dealt with player exchange deals.
The court also ruled that former Juventus chairman Andrea Agnelli be banned from holding office in Italian soccer for 24 months.
It also decided on a 30-month ban for Juve's former sports director, Fabio Paratici, now managing director of football at Tottenham.
Juventus have denied wrongdoing and said their accounting was in line with industry standards.
