German banker Christian Olearius is on trial for participating in a multibillion-euro tax fraud conspiracy involving local and global banks and hundreds of individuals.

The loophole that allowed trading between 2005 and 2012 is closed, but courts are still investigating to recover an estimated 10 billion euros ($10.66 billion) from government coffers.

Olearius denies misconduct but did not testify.

The case has political overtones, as German Chancellor Olaf Scholz has denied intervening in Warburg’s tax situation.