A New York judge has ruled that billionaire art dealer David Nahmad may owe millions of dollars in additional compensation to the heirs of the rightful owner of a Nazi-looted Amedeo Modigliani painting.

The decision comes just weeks after the court ordered Nahmad to return Seated Man with a Cane, concluding that the artwork had been unlawfully taken during the Nazi era.

In a ruling issued on Tuesday, Justice Joel M. Cohen said New York law requires the payment of prejudgment interest in cases involving the wrongful deprivation of property. This means the heirs may receive compensation not only for the return of the painting but also for the years they were unable to possess it.

The exact amount of compensation has not yet been determined.

The court has scheduled an evidentiary hearing in September to establish the painting’s current value. That valuation will play a key role in calculating the amount of prejudgment interest and the total financial award.

The case is one of several high-profile legal disputes involving artworks looted during the Nazi era, highlighting ongoing efforts to return cultural property to the descendants of its original owners decades after World War II.

The upcoming hearing is expected to determine the final financial implications of the ruling for both Nahmad and the heirs.