A French appeals court overturned a 2016 labor court decision against Société Générale SA and ruled that the bank was justified in firing rogue trader Jérôme Kerviel, Reuters reported Dec. 19.

The appeals court found no irregularities with SocGen's dismissal of Kerviel — whose unauthorized equity derivative trades cost the lender €4.9 billion in 2008 — and canceled the €455,000 amount that the French bank was ordered to pay him by the labor court in June 2016.

Kerviel maintains his former managers at SocGen knew the full extent of his €50 billion trading positions, which the French bank rejects. A Versailles court in September 2016 ruled that Kerviel was "partly responsible" for the losses and that SocGen failed to properly supervise him.

The former trader was imprisoned for a few months in 2014 before being granted an early release and has unsuccessfully tried to reverse the conviction since then. Kerviel's lawyer said his client is considering taking the case to France's highest appeals court, the newswire added.