A French state prosecutor has demanded that rogue trader Jérôme Kerviel serve five years in prison as an “example and a deterrent”, rebutting the former banker’s appeal against his 2010 conviction for losses he racked up at Société Générale on uncovered trades.

After his trial, Kerviel was sentenced to three years, with two further years suspended, and ordered to pay damages of €4.9 billion, matching the cost to the French bank of unwinding the €50 billion of trading bets he made in three futures markets in 2008.

Dominique Gaillardot, leading the state’s case against Kerviel’s appeal, told a Paris court that the ex-trader should serve the maximum term for his acts, describing him as “perverse and a manipulator”.

On Monday, SocGen’s lawyers had demanded that the appeal court also confirm the original award of damages against Kerviel, who has remained at liberty pending his appeal.

The appeal hearing is due to end today, with a verdict not expected to be delivered for some months yet.– Copyright The Financial Times Limited 2012